WHITNEY LIBRARY,
HAKVARD UNIVERSITY.

THE GIFT OF
J. D. WHITNEY,

Sturyis Hooper Professor

IN THE

MUSEUM OF COMPARATIVE ZOOLOGY.

^TiA^oA.

FROM THE

MEMOIRS OF THE MUSEUM OF COMPARATIVE ZOOLOGY,

AT CAMBRIDGE, MASSACHUSETTS.

(Volume VII. No. 2.)

THE

CLIMATIC CHANGES

OF LATER GEOLOGICAL TIMES:

A DISCUSSION BASED ON OBSERVATIONS MADE IN THE
CORDILLERAS OF NORTH AMERICA.

By J. D. WHITNEY.

CAMBRIDGE:
UXIVERSITY PRESS, JOHN WILSON AND SON.

1882.

University Phess:
John Wilson and Son, Cambridge.

CONTENTS.

CHAPTER I.

THE GLACIAL AND SURFACE GEOLOGY OF THE PACIFIC COAST.

SECTIOX L
Introductory 1-23

Eeasons for publishing tliis as a separate work, 1. Its connection with the
Tohime on the Auriferous Gravels, 1. Climatic results reached in the study
of Califoruian Surface Geology, 1, 2. Similar results obtained in the Cordilleras, 2.
Nature of the proposed discussion, 2. • — General considerations as to Geological
Results produced by ice, 3-12. Definitions of terms used, 4, 5. Nature of
Moraines, G, 7. Ice not of itself an erosive agent, 8. Proofs of this, 8, 9.
Striation considered, 9, 10. Striated Surfaces, how produced without the aid of
Ice, 10. Bodies Jtfoufoiniees, and imitations of, 10. The Ground ^Moraine, 11.
Geological Agencj'of Icebergs, 11, 12 ; of the Ice-foot, 11. — The Origin of Lakes,
12-19. Orographic Lakes, 12—16. Lakes of Central Africa, 12 ; Lakes, absence
of, in South America, 1.3. Lakes of North America, l-t-lG ; of the Great Basin,
16 ; of Canada and Finland, 17, 18. — The Origin of Fiords, 19-23. Erosive
work of Water subordinate to action of Orographic Forces, 22, 23.

SECTIOX IL

Former Gl.\ciation of the Sierra Nevada, of the Pacific Coast, and of the

Cordilleras in general 23-100

Simplicity of the facts of past Glaciation in the Sierra Nevada, 23. Mistakes
which have been made in spite of this, 23 ; reasons for these, 24. — Present
distribution of Snow and Ice in the Cordilleras, 25-33. No Glaciers in the
Sierra Nevada, 25 ; reasons for this, 2.'i, 26. Snow-fall in the Sierra, 26. Dis-
tribution of Snow in the Sierra, 27. Snow and Ice on Mount Shasta, 27-30 ;
on Mount Hitter, 30; on Hood and Eainier, 30; on Mount Baker, 31; in Brit-
ish Columbia, 31, 32 ; on the Great Basin Eanges, 32 ; on the Eocky Moun-
tains, 33. — Former Glaciation of the Cordilleras, 33-100; what was known
of this at the beginning of tlie Geological Survey of California, 34. General
Synopsis of results obtaine<l by the Survey in regard to past Glaciation, 34, 35. —
Details of past Glaciation in the Sierra Nevada, 35-62. Absence of Glacial
Markings in tlic soutliern part of the State of California, 35. Curious imitations of

VI CONTENTS.

boulders in the Teraescal Range, 36. " Wstslies " de-scribeJ, 3G. Passes and roads
across the Sierra, 37. No Glaeial Markings near Mount Whitney, 38. Former
Glaciation at head of Kern River, 38; on King's River, 39, 40 ; on the San Joaquin,
41; on the Tuohunne River, 41-43. Tuolumne Canon described, 42,43; not
formed by Ice, 42, 43. The Hetch-Hetchy Valley, 43, 44. Former Glaciation at
the head of the Merced River, 44-47. Absence of signs of former Glaciation in the
Yoseniite Valley, 47-50. Former Glaciation of ea.stern side of Sierra Nevada near
head of Tuolumne, 50, 51. Moraines near Mono Lake, 50 ; perfection of, on Green
Eivev, 52, 53. Traces of former Glaciation less distinct North of the Tuolumne, 53.
Former Glaciation of the Stanislaus, 53, 54 ; at the head of the Mokelumne, 55 ;
at the head of the American River, 56-59 ; in Sierra and Plumas Counties, 59, 60.
Absence of Glacial Markings on Lassen's Peak, 61. Former Glaciers of Mount
Shasta, 61. What was known of the past Glaciation of the Cordilleras before the
California Survey was begun, 62. i'ormer Glaciation of the Great Basin Ranges, 63 ;
of the Wahsatch Range, 63 ; the Uinta Range, 63, 64 ; of the Rocky Mountains,
64-72 ; in the Upper Arkansas Valley, 64 ; in Colorado generally, 65, 66 ; in the
Middle Park, 67; around North Park, 67; about the Head of the Yellowstone,
69 ; in tlie Wind River Range, 71 ; absence of Drift in the Black Hills, 71, 72. —
Defence of the Statement published by the Geological Survey, in 1866, iu
regard to absence of Northern Drift iu the Cordilleras, 7.?-'J2. Former Glaci-
ation of Nevada and Oreguii, 74, 75 ; of Washington Territory, 76 ; of British
Coluraliia, 76-92. Hector's Results, 76, 77. G. M. Dawson's Observations on
the Fraser, 79-80. Dall's work in Alaska, 81, 82. —Glacial Geology of Van-
couver Island discussed, 82-87 ; North of Vancouver Island, 87-90. Daw-
son's Views controverted, 90-92. Non-glacial Origin of the larger Californian
Lakes, 93-95. Moraine Lakes in the Sierra, 95. Lakes at very higli altitudes,
96. Freshness of Glacial INIarkings in the Sierra, 96, 97. — Forms of Valleys
and Canous discussed, 97-99.

CHAPTER 11.

THE DESICCATION OF LATER GEOLOGICAL TIMES.

SECTION L

iNTROnrCTORY 101, 102

SECTION n.

The Drying up of the L.\kes of the Western side of the Xouth American

Continent 103-120

Great Salt Lake, 103, 104. Depression in Southern California, 104, 105. Death
Valli'v, 105. Mono Lake, 106. Mr. Gilbert's Views, 106, 107. — Discussion of
Evidence furnished by the Fortieth Parallel Survey in regard to Desiccation
in the Great Basin and Rocky Mountains, 108-119. Great Salt Lake and Lake
Bonnevillr, 109. Lake Lahontan, 109-1 10. The Great Basin Lakes, 110. Brit-
ish Columbia, 1 1 2. Former abundance of Lakes in the Cordilleras, 112. — Pre-
glacial Desiccation in the Cordilleras, 113-120. Eocene Lakes, 116. Miocene
Lakes, 117, 118. Pliocene and Post-pliocene Lakes, 118, 119. The Parks, 120.

CONTEXTS. Vll

SECTION III.

Desiccation of the Asiatic Coxtixext, axd of other Portioxs of the World 121-154

Desiccation of tlie Asiatic Continent, 121-1-tl. Areas of the Continental
Masses compared, 121, 122. Position of the Asiatic Closed-Basin Region, 122.
Important results of Desiccation in Southern Asia, and on the Mediterranean, 123-
12.5. — Desiccation in the Aralo-Caspian Basin, 124—127. Humboldt's Conclu-
sions, 12."). Major Wood'.s Investigations, 12.5-127. Dr. Neuinayr's Results, 126.
— Desiccation in Persia, 128, 129. Statements of the Anglo-Persiau Boundary
Commission, 128. Present Population of Persia, 128. Dr. r>ellew's Statements,
128, 129. Blanford's Conclusions, 129. — Desiccation in the Himalaya, 1.30,
131. H. von Schlagintweit quoted, 130. F. Drew's Statements, 130, 131. The
Author of " The Indian Alps " on the Disappearance of the Forests in the Hima-
laya, 131. — Desiccation in the Thian-Schan Range, 131. Sewerzoff quoted,

131. — Diminution of the Lakes of Central Asia, 132-134. The Han-Hai,

132. Lob Nor, 133. Richthofen quoted, 132. Prjewalsky quoted, 133. Forsyth
on Desiccation in East Turkestan, 133. Siberia once covered in large part by
Water, 134. Cotta quoted, 134. Influence of Geological Changes on Man's Wel-
fare, 135-137. — Desiccation of the Region bordering on the Mediterranean,
138-149. Nature of the Evidences of Desiccation, 137. Changes of Climate in
Arabia in Historic Times, 138, 139. Statements of Fresnel, Noel des Vergere,
ami Lady Blunt, 138, 139. Diminution of the Rivers of Mesopotamia, 139.
W. Blunt quoted, 140. C. Fraas quoted, 140. E. H. Palmer's Statement, 140.
11. F. Burton on the Changes of Climate in Midian, 140, 141. C. Fraas on the
Climate of Egypt, 141, 142. Rusegger's Views, 142. A. L. Adams quoted, 142,
143. Linger and Fallmerayer on the Climate of Greece, 143. 0. Fraas, Remarks
on the Decay of the Mediterranean Nations, 144. — Increased Dryness of the
Sahara in Historic Times, 145-149. Zittel quoted, 145. Desor's Views, 14G.
Proofs of Change of Climate in Northern Africa, 146-149. Dr. Chavanne quoted,
147-149. — ^Diminution of the Lakes of Central Africa, 149, 150. — Living-
stone's Views, 150. — Desiccation in Central Europe, 150, 151. Results ob-
tained by Berghaus and Wex, in regard to the Diminution in Volume of the
Rivers of Europe, 151. — Drying up of the Lakes of South America, 151-153.
A. Agassiz, his Investigations, 152, 153. Humboldt's Observations, 153.

CHAPTER III.

GENERAL DISCUSSION OF THE DESICCATION QUESTION.

SECTION T.
Introductory 155-164

Results obtained in regard to Desiccation in the Sierra Nevada, 155, 150; in
the Rocky Mountains, 1;)7. Manner in which the subject of Desiccation has
been heretofore treated, 159. — Desiccation generally regarded as the Result
of Cutting do^wn the Forests, 160-164. Authors quoted as favoring this

viii CONTENTS.

view, 160-163. Palissy, 160; F. Simony, 161; Ladoucette, 161; C. F. Hartt,
162; E. D. Mathews, 162; Wilson Flagg, 162; F. B. Hougb, 162; The Boston
Daily Advertiser, 163; The N. Y. Nation, 163.

SECTION II.

Is Desiccation the Eesult of Partial or Entire Eemoval of the Forests

BY the Hand of Man ? 1G4-184

Discussion of the Causes influencing the Gro-wth and Distribution of
Forests, lG.5-170. Intluence of Temjierature, 16o ; of Moisture, 165-167 ;
of the Texture of the Soil, 167-169. Peschel's Views on this subject con-
troverted, 168, 169. — Desiccation begun before Man existed, 170, 171.
The Diminution of the Lakes of tlie Cordilleras and of Central Asia begun be-
fore Tertiary Times, 170. — Supposed Influence of Forests on Rain-fall
examined, 171-182. The Countries bordering on the Mediterranean not heavily
forested in historic times, 171. Burton's Observations in the Laud of Midiau
examined, 171, 172. Illustrative example in Nevada, 172. Incorrect statements
of authors in regard to California, 172, 173. Has New England become a Desert
in conse(|uence of the rapid clearing away of its Forests during the past fifty
years? 173, 174. Has the Climate of Egypt been changed by planting Trees?
175. Has the Climate of Salt Lake Valley undergone a Change in consequence
of Cultivation? 175, 176. Discussion of the Decrease of Great Salt Lake, 176,
177 ; of Winnemucca and Pyramid Lakes, 177. Is the Prairie Eegion a Desert?
177, 178. — Influence of Forests on Climate, and their Connection with the
Welfare of the People, 178, 179. Necessity of Economizing Water in Dry
Eegions, 179. Cloud-bursts and Character of Piain-fall in Dry Countries, 179. —
Supposed Antagonism between Man and Nature discussed, 180-183. Over-
irrigation, what it means, 182. Exhaustion of the Soil by Cultivation, 183.
Man cannot dominate Nature, 183, 184.

SECTION 111.

Desiccation as a Phase of the Glacial Erocii 184-193

Discussion of the Vievr generally held by Geologists that the Phenomena
of Desiccation are simply a Phase of the Glacial Epoch, 185-192. Authors
quoted as holding this view, — H. C. Lewis, 185; N. H. Winchell, 186; S. F.
Emmons, 186 ; G. K. Gilbert, 186 ; R. D. Irving, 187 ; N. S. Shaler, 187 ; C. H.
Hitchcock, 187. Professor Dana's views, 187, 188. English authors quoted on
the same subject, — D. Mackintosh, 189 ; J. Geikie, 189. — The Views of these
Authors controverted, 190-193. Melting of the Great Glacier, 192. Diminu-
tion of the Rivers of Europe synchronous with the Rapid Decrease of tlie Gla-
ciers, 192, 193.

SECTION IV.

Examination of the Conditions favoring, or tending to diminish Precipi-
tation upon the Earth's Surface 193-204

What canses Precipitation? 193, 194. Irregularity of the Distribution of the
Rain-fall on the Earth's Surface, 194. — Conditions affecting the Amount of
Precipitation, 194—198. Precipitation in the Equatorial Regions, 190, 197. Areas

CONTENTS. IX

of Small Precipitation on eacli side of the Equatorial Belt, 197. Sub-tropical Zones
of Precipitation, 197. Regions of Constant Rain.s, 198. — Conditions affecting
the Distribution of Precipitation, 198-203. Interiors of large Continental
Masses, dr\', 199. Regions of abnormally large Precipitation, 199. Distribution
of Pain and .Snow on Mountain Panges, 200. The :Monsoon Winds, 200, 201. —
Climatic Condition of the Region east and south of the Mediterranean dis-
cussed, 201-203. Faniiiios in India (note), 201. Wojeikof on tlie Climatic
Peculiarities of the Saliara, 201, 202. Distribution of Rain and Snow in the Po-
lar Regions, 203. Conditions favoring Precipitation in the form of Snow, 204.

SECTION V.

Has the Extent of Land Surface on the Globe been, on the whole, in-
creasing WITH the Lap.se of the GEOLOGICAL Age 203-219

The Continental Masses have, with tlie Lapse of Geological time, been growing
larger, 205. Reference to the IMaps of Delesse, 206. Manner in whicli Detri-
tal Materials accumulate, 207. How tlje Continents have been built up, 207,
208. A Gain of Land tlie Xecessary Result, 208. Permanence of the Ocean
inferred from its great depth, 209. Stability of the Continents a necessary conse-
quence, 207. Mean Elevation of the Land Masses of the Globe, 209. Persist-
ence of Areas of Elevation and Depression first enunciated by Dana, 200. Geo-
logical Growth of Nortli America, 211 ; of Asia, 211. Foster and Whitney, quoted,
211. — Evidence of the Stability of the Oceanic Areas derived from the
Character of the Sea Bottom, 214-216. Investigations of Agassiz, 214.
Views of A. Geikie and W. 11. Carpenter, 215. Summary of the Evidence, 216.
— Inquiry whether the Increase of the Continental Masses is SufEcieut
Cause for the Desiccation proved to have taken place, 210-219. I'rcjbaljlc
Effects on precipitation of Changes, in the form of the Land Ma.sses, 217. Higher
temperature suggested as a cause of former Greater Precipitation, 218.

SECTION YL

Examination of the Evidences of former Changes of Temper.ature on the
Earth. Has the Solar IIadi.xtion been diminishing in Intensity dur-
ing all or any portion of the Geological Periods? 219-257

The term Geological Climates defined, 219. Tlie Glacial Epoch usually consid-
ered the only Cliiuatic Phase of importance, 220. — Investigation of Temperature
Changes during the Historic Period, 221-240. Difficulty of procuring proof of
Diminished Riiin-fall by means of Instrumental Observations, 222. Range of rain-
fall in various Regions, 222. Easier to determine the Mean Temperature than the
Meau Precipitation, 223. How far back do Records of Instrumental Observations
extend? 223, 224. When the Thermometer began to be regularly observed, 224.
Serious source of error in Thermometrical Observations not noticed until 1817,
224. Arago's investigations of the Mean Temperature at Paris, 224, 225. Loomis
and Newton's investigations of the Mean Temperature at New Haven, 225, 226.
Smithsonian Observations worked up by Schott, 226. Plantamour's investigations,
227. Dove and Quetelet cited, 227. Glaisher's Results near London examined,
227, 228. Summary, 228, 229. — Examination of Historical Records of Cli-
mate, not instrumental, 229-241. Arago's investigations examined and criticised,

X CONTENTS.

229-236. Has the Climate of Palo,stiiie remained luichangecU 231, 232. The
Culture of the Date-Palui and its relations to Climate, 232, 233. Fischer quoted,
232. Bellevv cited, 233. Liot on the Climate of China, 233. Arago on changes in
the Climate of Tuscany, 233 ; of France and England, 234, 236 ; changes supposed
by him to have taken place in North America, 23.5. Investigations of Loomis and
Newton again mentioned, 236. Change of Climate in Central Franco, 236.
Dying out of the Forests in Iceland and Lapland, 236 ; in the Alps ; in Siberia,
237. Vegetation of the Steppe working westward, 237. Name of the month of
November in various Sclavonic languages, and inferences from this, 237, 238.
Strong evidence of a Change of Climate in Greenland, 238 ; Arago cited on this
subject, and his views in part controverted, 238, 239. History of the Colonization
of Greenland (in note), 238, 239. Decay of Iceland, 239, 240. Increasing diffi-
culty of access to the North Polar regions, 240. Summary of evidence of Change
of Climate within the Historic Period, 241. — Examination of the question
■whether there has been a Change of Climate during the Geological Epochs,
241-2.57. Why the evidence must come almost exclusively from the Land, 242.
Ilesults of the investigations of Les(]uereux on the Fossil Plants of the Gravels of
the Sierra Nevada, 243 ; on the Fossil Vegetation of the Rocky Mountains, 244-
246. Proofs of former Warmer Climate in the Cordilleras, derived from the Fossil
Remains of Animals, 246, 247 ; S. H. Scudder cited, 247. Evidence afforded by
the Fossils of the Carboniferous Limestones in (irinnell Land, and North of the
Arctic Circle, 247, 248. — Investigations by Heer of the Fossil Plants of the
Arctic Regions, 248-250. Former extensive development of the Carboniferous
form.ation in high northern latitudes, 248. The Vegetation of the Cretaceous
period, 249. The Miocene plants of West Greenland, 249. Vegetation and
Climate of the Arctic Regions during the Tertiary epoch, 249, 2.50. — Saporta's
Review of the indications of Changes of Climate afforded by Fossil Vege-
tation, 251-253. Character of Climate indicated by the Plants of the Carbon-
iferous epoch, 251 ; by the Vegetation of the Cretaceous period, 251. Conclusions
with regard to the Character of the Climate in Central Europe during the Tertiary
Epoch, 251, 253. — Summary of Evidence, and General Remarks on Climate
and 'Weather, 254-257. Arago's Tables of the Times of the Freezing of the
Great Rivers of Europe and of the Occurrence of Mild and Severe Winters
commented on, 254, 255. Obscurity of the Causes of the Fluctuations of the
Weather, 256 ; they are not connected with the Sun-spot Cycle, nor regularly
recurrent, 256. The Movements of Storms can be indicated after they have
begun, but the Time of their Inception cannot be predicted, 256, 257.

SECTION VII.
Theories of the Cause of Temper.iture Changes 257-264

General Sketch of the Various Theories proposed to account for the Changes of
Temperature on the Earth, 258. Poisson's Theory, 259. Theories connected with
supposed Changes in the Position of the Earth's Axis, 259, 260. Sir W. Thom-
son's Opinion of them, 260. Changes of Climate as connected with the Cooling
of the Earth's Interior, 261. Sir VV. Thomson again cited, 261. The Diminish-
ing Heat of the Sun indicated as the probable cause of the Earth's Lessened Tem-
perature, 262, 263. Newcomb cited, 262. Sir W. Thomson cited, 26.3. Resume
of Chapter III., 204.

CONTENTS. XI

CHAPTER IV.
THE SO-CALLED "GLACIAL EPOCH" AND ITS CLIMATIC CONDITIONS.

SECTION L

Introductory 265-268

Views generally entertained with regard to the nature of the Climate of the
Glacial Epoch, 265. What is expected to be proved in this chajiter, 266. Diffi-
culties to be encountered, 266 ; these ordinarily overlooked, 266. The author's
opinion of Unifomiitarianism, 266. Order to be followed in the presentation of
the subject, 267, 268.

SECTIOX II.
Present Distribution of Sxow .vxn Ice throughout the World . . . 269-325

Present Glaciatioii of South America, 269-273. The Andes of Ecuador,
270, 271 ; Mr. Whymper's Observations noticed, 270. Snow and Ice in the Pe-
ruvian Andes, 271 ; in the Andes of Chili, 271, 272. Peculiar Climatic Condi-
tions in Chili resembling those of the Sierra Nevada, 271, 272; Darwin quoted,
272. Investigations of Pissis, 272. Snow-line and Glaciers in Tierra del Fuego,
272, 273. Small amount of Snow and Ice in Africa, 273. Glaciers of New
Zealand described, 273, 274. I'roofs of former Greater Precipitation in New
Zealand, 274. — Present Glaciation of the Asiatic Continent, 274-28.5. Im-
portance of the facts obtained on this Continent in their bearing on the present
discussion, 274. Topography of High Asia, 275. The Arabian and Iranian
Table-Lands, 275. Glaciers of the Caucasus, 276. Climatic Condition of the
Ural, 277 ; of the Pae-Choi Range, 278; of Central Asia, 278-285. The Panges
by which Central Asia is framed indicated, 278, 279 ; Distribution of Ice and
Snow.in these Ranges, 280. Climatic Conditions ot the Thibetan High Plateau,
280 ; of the Kuen-Luen Range, 281 ; of the Karakorum Range, 281 ; of the Pamir
Plateau, 281, 282 ; of the Thian-Schan Range, 282 ; of the Altai Mountains,
282 ; of the Himalaya, 284, 285. Height of the Snow-line in the Himalaya,
285. — The Glacier Regions of Earope, 285-289. The most important Glacier
Systems of the Alps mentioned, 286. Height of Snow-line in the Alps, 286.
Glaciers of the Pyrenees, 286 ; of the Scandinavian Range, 287-289. Justedal,
Fondal, and Folgefon, 288. Delicate balancing of conditions fovoring Glaciation
in the Scandinavian Range, 288, 289. — Climatic and Glacial Conditions of the
Polar Regions discussed, 289-318. Importance of these regions in connection
with the present discussion, 289, 290. — Peculiar distribution of Land and Water
in the Northern Hemisphere, 290, 291. Freezing of the Ocean and formation of
Ice on Land contrasted, 292. Present Glaciation of Spitzbergen, 292, 293 ; of
Nova Zembla, 293, 294 ; of Franz Josefs Land, 294, 295 ; of Iceland, 295,

296. Emigration from Iceland (in note), 295. — Climatic and Glacial Condi-
tions of Greenland discussed, 296-307 ; its geographical position described, 296,

297. Probible character of the Interior, 297. Explorations of the Inland Ice,
298-303. Exj.editiun of Dalager, 298 ; of Hayes, 298, 299 ; of Nordenskjold,
299 ; of Bessels, 299, 300 ; of Amund Heiland, 300, 301 ; particulars of Hellaud's

XU CONTENTS.

Observations of the Rate of Motion of tlie GlaiaiTS of Grcenlani), 301. Explora-
tions of Steenstrup and Jensen, 302, 303. E.xplorations of the eastern side of
Greenland, 303-306. Sketch of the progress of geographical discovery on the
eastern side of Greenland (in note), 303. E.\plorations of Scoresby, 304 ; of Clav-
eriug and SaViine, 304; of Graah, 304; of Payer and the officers of the " Hansa,"
304, 305. Koldewey on the absence of deep Snow and Ice on the eastern shore
of Greenland, 30-5. Probable character of the Interior discussed, 306, 307.
Absence of Ice on part of the western shtire, 307. Contrast in the (.Jlacial Char-
acter of the two sides of Kennedy Channel, 307. De liance and Feilden quoted, 307.
Nares quoted, 307, 308. Bessels on the absence of Glaciers on the west side of the
Cliannel opposite Greenland, 308. Small amount of Ice and Snow in North
America between Hudson's l!ay and the Mackenzie River, 308. Sir J. Eich-
ardson quoted, 308. Sir E. Belcher's Statements in regard to the small amount
of Snow or Ice about Northumberland Sound, 309. Middendorff and Nor-
denskjbld on the absence of (Jlaciers and the small amount of Snow in Northern
Asia, 309. Summary of results as to Snow and Ice in the North Polar ' Regions,
310. — The Climatic and Glacial Conditions of the South Polar Regions dis-
cussed, 311-318. Small amount of geographical knowledge of lands lying
within the Antarctic Circle, 311. Climate of the Islands in low Southern Lati-
tudes, 311, 312. Amount of Land in the South Polar Region, 312, 313. Re-
sume of Geographical Discoveries near the South Pole (in note), 312. Petermann's
Views in regard to the amount and insular character of the land within the An-
tarctic Circle, 313. Explorations of Sir J. C. Ross, 314-316 ; of Dumont d'LTrville,
316. Peculiar Climatic Conditions of the Antarctic Polar Region, 316-318. Ice-
fields of that Region perhaps the result of the freezing of the Ocean Surface, 318 ;
Miihry's Views on this point, 318. The Floe-bergs of the Nares Expedition (in
note), 318. Discussion of the facts presented in regard to Present Glaciation
of parts of the Earth's Surface, 311)-32.5. Preciintation in the form of Snow,
how caused, and in wliat manner distributed, 319, 320. Cold not sufficient to
produce a copious Snow-fall, 320. Tlie Glacial Epoch not necessarily a period of
intense cold, 321. Possibly there is now more Snow and Ice on the Globe tlian
ever before, 321. Glaciers and permanent Snow-Helds the appendages of Moun-
tains and high Table-lands, 322. Could Glaciers originate on level land % 322, 323.
How Snow is cduverted into Ice, 323, 324. Pressure not sufficient for this in
Nature, 324. Illustrative example from Mount Shasta, 324. Glacier Ice a mix-
ture of Ice and Water, 324, 32-5.

SECTIOX in.

PiECENT Changes in Gl.vciek Regions 325-342

Object of the inquiry stated, 325, 326. The case stated in a general way, 326.
The work of the Alpine Clubs, 327. V. Payot's record of the Oscillations of the
Mont Blanc Glaciers (in note), 327. Facts in regard to these, 328. Shrinking of
the Glaciers of the Eastern Alps, 329. The Glacier of Gebrulaz, 329. C. E.
Mathews quoted, 329. C. Dufour quoted, 330. Trutat on the Recession of
the Glaciers of the Pyrenees, 330. Abich on tlie Diminution of the Ice Masses of
the Caucasus, 331, 332. — AWhat the Oscillations of the Alpine Glaciers mean,
332, 333. Gruner's Investigations noticed, 333. Shrinking nf the Glaciers of the
Himalaya and of the Scandinavian Range, 334. Glaciers with extremely-
irregular Oscillations, 334-336. The Vernagt, 334, 335. The Glacier of Dev-

CONTEXTS. xiii

(lornk, 335. Xonlenskjold's Observatiuiis on Spitzbergen, 335, 336. — Inquiry
■whether any Meteorological Changes corresponding to the Oscillations of the
Glaciers can be detected, 336-341. Meteorological Observations in Switzerland
worked up by Plaiitamour, 33G-338. Views of M. Gruner controverted, 339.
Haun's Opinion (juoted, 339. C. Dufour on the lietreat of tlie Glaciers, 339.
Resume of Eesults reached in the present section, 340, 341. The ideas generally
entertained by Geologists in regard to the Eocession of the Glaciers during tlie past
half-century, 341. What the Author thinks about it, 341, 342.

SECTION IV.

The Former Extensiox of Snow and Ice over Eegioxs xot so covered at

THE Present Time. The so-called " Glacial Epoch " 342-387

Conditions of Past Glaciation discussed, 343, 344. Two Regions oidy where
Phenomena of Past Glaciation are of special importance, 344, 345 ; Extent of
these Regions indicated, 345. — Past Glaciation of High Asia, 346-354. Inves-
tigations of the Scldagintweit Brothers, 347, 348. Results arrived at by the India
Geological Survey, 348, 349. No evidence of a Cold Epoch in India, 349. In-
vestigations of Sewerzoflf in the Thian-Schan Range, 349, 350. Contradictory
evidence of Mousliketofl', 350. Past Glaciation of the Altai Range, 350. Cotta
and Helmerseu quoted, 350. Absence of traces of a Glacial Epoch in Cluna,
350 ; in the Ural, 351. Former greater extension of the Caucasian Glaciers, 351,

352. Abicli and Favre quoted, 351. Former greater extension of ice on Ararat,

353. Tchihatchell' on the~ absence of traces of a Glacial Epoch in Asia Minor,
353. J. D. Hooker on Moraines in the Lebanon Range, 353. Hooker's views not
sustained by Lartot, 353. 0. Fraas on Glacial Erosion in Syria, 353. Former
greater size of the Glaciers of New Zealand, 354. Absence of past as well as
present Glaciation in Africa, 354. G. Maw on traces of Glaciers in the Atlas
Range quoted, 354. Former Glaciation in South America, 355. The Glacial
Epoch on the west side of Xortli America, 355. — Former greater Extension of
the Glaciers in the Alps, 356-361. Simplicity of the facts, especially on the
south side of the Range, 356, 357. Traces of Former Glaciation less marked
towards the eastern extremity of the Range on tlie nortli side, 357. Views of
Advanced Glacialists, 357, 358. F. Stark's Map of the ancient Glaciers of South-
eastern Bavaria, 358. His Views not fully sustained by the author, 359. Diffi-
culties presented, and Zittel's Views of the same, 359. The ancient Glacier of
the Rhone, 360. Investigations of Falsan and Chantre, 360, 361. Former
Glaciation of tlio Pyrenees, 361 ; of the Vosges, 361. — The Glacial Epoch in
Scandinavia and the adjacent Countries, 362—371. Sequence of events iu
Scandinavia during the Glacial Epoch, as established by the Swedish Survey,
362-364. Extension of the Scandinavian Ice Sheet into Russia, 365-367. Mnr-
chison's Views, 365. Investigations of Grewingk in the Baltic Provinces, 365, 366 ;
of Fr. Schmidt in the same region, 366. Helmersen on the Glacial and Surface
Geology of Russia, 366, 367. Difficulties presented in regard to former extension
of the ice sheet over Russia, 367 ; similar difficulties in regard to North Germany,
Holland, and the British Islands, 367-370. Origin and character of the Diluvium
of North Germany, 368, 369. Martin's Investigations in Holland, 368, 369.
Credner's Views, 369. Opinions of A. Jentzsch, 369, 370 ; of Messrs. Peach and
Home, 370. Local Glaciers on the British Islands, 37l>. Extent of Glaciated
Area dependent on the Scandinavian Centre, 371. — Discussion of the facts

xiv CONTENTS.

presented, 371—374. The past and present Glacial Couditions of the Ural, of the
Scaudiiiavian Ran<;e, and of We.'^t Greenland compared and commented on, 371-
374. — Past Glaciation of Northeastern North America, 375—387. Complica-
tion of the Phenomena, 375. Statement of the Facts, 37C-378. Character of the
Northern Drift, 376. Topographical Features of the two sides of the Continent
compared, 376. Depressed area in central portion of Drift Region, 376, 377.
Nature and distribution of the Drift Material, 377, 378 ; area over which this is
chiefly developed, 378 ; direction in which it has been carried, 378. Indications
of former greater Rainfoll, and of Currents of Water, 379. Opinions earliest held
by heads of great American Surveys in regard to the Origin of tlio Drift, 379, 380.
Difficulty of malving out the po.sitions of the Ancient Rivers, 380. The former
presence of Ice rendered necessary by the existence of Striated Rock Surfaces, 380,

381. Character of this Striation, 381, 382. The Inland Ice of Greenland cannot be
accepted as explaining the Drift Phenomena of Northeastern America, 382. The
theory tliat the Ice of Greenland once extended over North America examined,

382. — Examiuatiou of the question of the former existence of a General or
Continental Glacier, 382-385. Professor Dana's Views, 382, 383. Facts about
Ktaadn, 383, 384. Profes.sor Hamlin's Observations (in note), 383, 384. Ex-
amination of the evidence that a Continental Glacier once passed over the White
and Adirondack Mountains, 384. Boulders and gravel not proof of former
presence of Ice, 384. Complication of the Striation in New England, 384, 385.
G. A. Wheelock quoted, in regard to the Striation on and about Monadnock, 385.
Theories of the movement of the Continental Glacier in various directions at the
same time, 385. Ideas of J. F. Carll and Professor Dana, 385. The Continental
Ice sheet extended fiir beyond tlie limits which ought, by any possibility, to be
claimed for it, 385. Geological importance of tlie Ground Moraine much exag-
gerated, 386. The presence of Ice often invoked where Water really did the
work, 386. The foots in regard to Past Glaciation in Northeastern America not
yet sufficiently studied out to justify extensive tlieorizing, 386.

SECTION V.

Pii^suMi^ AND Gexer.vl DISCUSSION 387-394

The theory of a Polar ice-cap must be abandoned, 387. The Glacial epoch a
Local Phenomenon, 387. An increase of cold would not bring about Extensive
Glaciation, 388. Views of Lecoq, 388, 389. The theory advocated by Frankland,

389. The phenomena of the Glacial epoch a magnified form of Present Conditions,
389. — Comparison of the facts observed in various regions, 389-391; the
Caucasus, 389 ; the Sierra Nevada, 390 ; the Alps, 390 ; the Scandinavian Range,

390, 391; Northeastern America, 391. — Theories of a Recurrence of 'Warm
and Cold Periods on the t-wo hemispheres discussed, 392-394. The views of
Adhemar and CroU, 392. Evidence in support of these views, 393. The author's
opinion of the value of this evidence, 393, 394. General conclusions, 394.

THE

CLIMATIC CHANGES

OF

LATER GEOLOGICAL TLMES.

THE CLIMATIC CHANGES

OF LATEU GEOLOGICAL TIMES.

CHAPTER I.

THE GLACIAL AND SURFACE GEOLOGY OF THE PACIFIC COAST.

Section I. — Introduction.

This chapter and the following one form the basis on which the present
voliitne rests. Tliey were originally intended to be included in a work en-
titled •' The Auriferous Gravels of the Sierra Nevada of California," a part of
which has been already published, while the appearance of the remaining
portion will not l)e much longer delayed.* The reason why it has been
decided to make a separate work of the glacial geology is, that the quantity
of matter was found to be unexpectedly large, so that a volume which should
contain the whole results of the investigation would be inconveniently bulky.
The gravel deposits of the Sierra Nevada do, indeed, form a special subject
of inquiry, and a single volume may most properly be devoted to their ex-
clusive consideration. Moreover, by separating the discussion of the glacial
phenomena from the description of the auriferous gravels, a wider range
could be given to the former, which coiu'se seemed, after the Avriting out
of the work for publication had been taken seriously in hand, to be most
desirable.

The study of the mode of occurrence of the formations described in the
gravel volume led the writer to form certain conclusions with regard to the
physical conditions prevailing during the epoch of their deposition.! It
seemed to him to be most clearly made out that a precipitation, greatly in
excess of that which is now taking place in the same region, was the most
important agent in bringing about the accumulation of those great masses

* That work will be cited in the present one as the "Auriferous Gr.avels," or simply as the "gravel volume."
It forms the sixth volume of the Memoirs of the Museum of Comparative Zoology,
t See t'lia[iter IV, seetious 5 and 6 of the Auriferous Gravels.

2 GLACIAL AND SURFACE GEOLOGY OF THE PACIFIC COAST.

of detrital materials whose geological peculiarities as well as whose richness
in gold has made them so interesting to scientific and practical men.
That the climate, during this period of greater rain-fixll, was wanner than it
now is, appears also to have been proved by the character of the vegetation
prevailing during deposition of the gravel.

But in the course of the investigations of the California Survey it long
ago became evident that the present epoch is one of desiccation ; or, in other
words, that there has been, during the most recent geological times, a con-
stant diminution in the quantity of the water standing and flowing upon the
surface, throughout the region of the Sierra The same condition of things
has been proved to exist in the central and eastern portion of the Cordilleras
by the Fortieth Parallel and otlicr Surveys wliicli have more recently been
extended over that region.

Again, we have to go but a short distance back in geological time whi3n
we find that a portion of the area enibrace<Ll within the field of our observa-
tions was covered by snow and ice ; so that we have offered to us, as occurring
between epochs of great precipitation and of rapidly increasing desiccation,
a period of ice extension, limited, it is true, to the higher portions of the most
elevated ranges of the Cordilleras, but still general enough to imply tlie
existence of some peculiar conditions at the time of its occurrence.

Thus, then, we find ourselves led, by the observation of phenomena
connected with the geology and physical geography of the region west of
the Roclcy Mountains, to recognize at least three well-marked stages of
climatic change; and the question which naturally presents itself in this
connection is, whether a similar succession of events can be shown to have
occurred in other regions, or generally throughout the world. If, as appears
highly probable, this is the case, then we are led to inquire whether this
sequen(!e of changes is merely a series of disconnected events, in no way
interdependent and not capable of being referred to an^^ common cause ; or
whether, on the other hand, they are all linked together, as manifestations
of one common cause, which has been acting through all geological time, and
Avhich will continue to act in the future. The inquiry thus hinted at forms
the main object of the theoretical discussion which follows the presentation
of facts occupying the first two chapters of the present volume ; and the
writer hopes that he has been able to throw some light on the cliaracter of
the climatic changes which have taken place during the later geological
times.

INTRODUCTORY. 3

The scope of this discussion makes it necessary to introduce a considerable
body of facts relating to the glacial and surface geology of regions not in-
cluded within the Cordilleras. These to^iics must, of course, be treated in a
very general way, for space would by no means permit of entering into
minute details in regard to all the countries necessarily embraced within tlie
field of so comprehensive an inquiry. To a very considerable extent the
writer's own observations will be relied on as forming the basis of facts on
which the discussion rests ; but the endeavor will be made to give due credit
for all the information obtained from other sources, and the reader will be
directed where to find such additional material as may be accessible in the
works of trustworthy authors, who have contributed matter of importance in
the line of this inquiry.

In order to the better understanding of that which follows, it will be
necessary to begin with some remarks on glaciers and ice-work in general.
The scope of these remarks will be understood by those who read this
chapter, and they will also see why what may, at first view, seem to be
elementary considerations have been introduced into the present volume.
The course here to be followed is particularly necessaiy in connection with
Californian geology, because nowhere have such wild and absurd statements
in regard to the work done by ice been published as in discussing the
geological features of the Sierra Nevada. But it is true, also, that among
geologists generall}' there has been, of late years, a decided tendency to
exaggerate the importance of the work done by ice, and to leave out of
consideration the preponderating intliience of water in connection with so-
called glacial phenomena. In the early stages of geological discussion the
action of the ocean was the all-important factor : then ice had its day ; and
it is only quite recently that rain and rivers have begun to be recognized as
being also extremely important agents in the formation, transportation, and
deposition of detrital materials. The study of the gravels of the Sierra Nevada
can hardly fail to convince the candid investigator that the work of rivers
in that i-egion has been of great geological importance. And it is confidently
believed by the writer that the following chapter will fully illustrate and
bear out the statement that, in the Sierra Nevada at least, ice has played
but an extremely subordinate part as a geological agent, although there is
no doubt that the great Californian range was once covered with grand
glaciers, but little, if at all, inferior to those which now lend such a charm,
both from a picturesque and geological point of view, to the Swiss Alps.

4 GLACIAL AND SUEFACE GEOLOGY OF THE PACIFIC COAST.

In endeavoring to give as clear an idea as possible of the character of the
geological work Avhich ice is now doing in various parts of the world, the use
of some technical terms will be necessary. Most of those commonly em-
ployed in the text-books are, no doubt, familiar to the reader; but for a
more precise understanding of the discussion which follows, it will be desir-
able to define and limit the use of certain terms of frequent occurrence, so
that these may be employed without any danger of their use leading to
erroneous ideas. The language is, it is true, deficient in words required
to express what is often needed to be said in such a way as to include no
theoretical views. Even with the aid of Latin words, the difficulty has not
been entirely gotten over.

The simple word " gravel " has been employed in the gravel volume for
the mixture of rounded pebbles and boulders with finer water-worn mate-
rials, with which the surface and hydraulic miner has to operate. As used
throughout that work, it is of the natiu-e of a miner's technical term, any
unconsolidated detrital material washed for gold being called " gravel," while
the more or less consolidated is usually distinguished as " cement." In the
present volume the term " gravel " will be used with its ordinary significa-
tion, as meaning a mass of miconsolidated detrital material, made up chiefly
of moderate-sized rounded and water-worn fragments of rock, which uuvy be
more or less mixed with sand, and according to its condition may be called
coarse or fine gravel, sandy gravel, etc.

The term " diluvium,*' formerly much used for the superficial detrital
deposits, has pretty much gone out of use, and been replaced by " drift."
When, however, it is intended in the course of this chapter to refer to
" drift," without any limiting of the meaning, or implication that it has been
transported from any distance, the word " detritus " will be used, with the
corresj)ouding adjective "detrital." By detritus is imderstood any uncon-
solidated deposit of fragmental material, be the same coarse or fine, homo-
geneous or non-homogeneous, water-worn or angular, brought from a distance
or derived from rocks close at hand. By the term "drift" will be designated
such detrital deposits as have been moved to some distance from their
original place of occurrence ; and by " northern drift " is meant the detrital
deposits of Northeastern America, which have been carried in a more or less
southerly direction over a large area of country. The term " moraine " will
be applied to such deposits as are known by their character and position to
havo been left in their present position by glaciers. Most if not all of the

INTRODUCTORY : THE GEOLOGICAL WORK OF GLACIERS. 5

detrital material of Northeastern North America is destitute of any true
morainic character. Under the idea that, notwithstanding this fact, it has
had a glacial origin, and hence must once have had a structure analogous to
that of true moraines, much of it has been designated as " modified drift " ;
by which term it is meant to be understood that its real origin has been to
a certain extent masked by the action of water.

Detrital material arranged in long linear accumulations, somewhat resem-
bling moraines, but partly stratified and differently situated with regard
to the topography of the country from I'eal moraines, are called sometimes
by the Swedish term "as" (plural asar). The Scotch word " kame " is very
closely analogous to as in its meaning, and it has been iised on this side of
the Atlantic, as well as on the other. As defined by J. Geikie, it includes
sands and gravels having a tendency to shape themselves into mounds and
winding ridges, which give a humraocky and rapidly luidulating outline to
the ground.* The peculiarities of the asar will be noticed somewhat in
detail, when describing the glacial phenomena of Scandinavia.

The finer kinds of detrital material resulting from the wearing down of
the rocky masses are variously designated, and usually by terms not liable
to misconstruction. The quartzose portion of the rocks, especially the quartz
itself, yields slowly to degradation, and is not so easily reduced to the finest
condition ; argillaceous rocks, on the other hand, readily allow themselves
to be ground into the finest powder : hence we have sands, which are usually
chiefly quartzose, and clays, or finely triturated argillaceous material. Of
course sand and clay may become mechanically mixed with each- other,
and such mixtures are easily designated. The term '' alluvium," with the
corresponding adjective " alluvial," was originally used in opposition to dilu-
vium and diluvial as implying a less turbulent origin, and as indicating the
work of the present rivers, rather than of former larger and more general
fioods. When it is desired to define the different varieties of alluvial deposit
and limit them by names, it is not found to be an easy matter, and certain
terms have become quite generally adopted, but which are not capable of
precise definition. It is not easy, for instance, to draw the line between
"soil" and "loam," nor between "loam" and "loess," the latter being a
term which has of late years come into quite genei'al use, and including, as
characteristic features of the material thus designated, fineness and uniform-
ity of texture, and absence of any well-marked lines of stratification. Loess,

* J. Geikie, The Great Ice Age, p. 228.

6 GLACIAL AND SURFACE GEOLOGY OF THE PACIFIC COAST.

then, is very nearly the equivalent of the English word loam ; perhaps the best
way to define it would be to say that loam when developed enough to become
a formation of geological importance, and not a mere surface deposit, is loess.

The chief difficulty in investigating the work of glaciers lies in the fact
that ice and water act together in almost all tliat is done in the way
of bringing about geological changes in and near the glacier. In regard
to a portion of this work it is impossible to say ice has done this, or ivatcr has
done that ; the two have acted toi!:ether in brino-ino: about the visible result.
xVnother consideration to be kept in mind is this, — that the glacier is not a
body of a certain fixed length. At the present time, and in former days,
glaciers increase and diminish in length and thickness, sometimes rapidly, at
other times slowly, and with repeated alternations of growth and diminution.
In these changes part of the previous work of the glacier is oblitei'ated, a
part obscured, and, on the whole, the difficulty of distinguishing what is
due exclusively to ice action is much increased.

The simplest function of the glacier is that of carrying detritus. The
fragments detached from the walls of the valley through which the icy mass
passes fall upon the surface of the glaciei-, and resting upon it move down-
wards until they reach its terminus. The characteristic features of the
detrital material thus carried, and to which the name of " moraine " is applied,
are its angularity, and the absence of any regularity in the way in which it
lies, eitber while on the glacier itself or after having been delivered at the
terminus. Tlie material of the lateral moraine, or the detritus accumulated at
the edges of the glacier, when dumped at the end of the route becomes the
terminal moraine. A small portion of the detritus which falls on the glacier
falls through crevices or gets otherwise entangled in the ice, and is lost to the
moraine proper; but by f;ir the larger portion reaches the end of its course
very nearly in the same angular condition, and with the same heterogeneous
character, which it had at the beginning of its journey. The form and size
of the fragments of which the moraine is made up depend, of course, on the
character of the rock formations over which the glacier moves. The pieces
of rock rolled down from above will be transported with equal facility
whether — as is sometimes the case — of enormous size, or only in the form
of mere pebbles or sand. This is the criterion by which unaltered morainic
detritus may be recognized, and by which it may be distinguished from any
detrital deposits in the formation of which water has played a part.

The character and position of the terminal moraine will vai y largely with

TNTRODUCTOEY : THE FORMATION OF MORAINES. 7

the size of the glacier itself, and will also be greatly dependent on the cir-
cnmstances of the advance and retreat of the glacial mass. If the glacier be
very wide, and the lateral moraines small in proportion to the glacier itself,
the terminal moraine will be almost exclusively limited to the two sides
of the valley at the extremity of the glacier ; if the latter be narrow and
carrying a large quantity of detrital material, the lateral moraines will
coalesce and form a single terminal one, bai'ring the valley, except where
the stream of water which must issue from the extremity of every glacier
finds its way out. If the meteorological conditions are such that the glacier
during a long period neither diminishes nor lengthens, the terminal moraine
will become very large, and will gradually accumulate so as to cover a
considerable portion of the ice itself, as is the case with some of the large
glaciers of the Himalayan ranges. If, on the otlier hand, the glacier is, on
the whole, decidedly shrinking, the terminal moraine will bo less distinctly
marked, because the detrital material is always being dumped a little farther
up the valley.

When the glacier is advancing the phenomena become somewhat com-
plicated. The ice, as it moves forward, shoves a portion of the detritus
of previous morainic accumulations before it, and rises over another portion,
which is then in a condition to be rapiflly acted on by the glacier stream,
and is soon converted into rounded Ijoulders, with the synchronous formation
of much gravel and sand of greater or less fineness.

The phenomena of the lateral and terminal moraines are quite simple as
compared with those of tlie so-called "ground moraine," — that is, the detrital
material which lies under the glacier, and over which it moves. In regard
to the importance of this material there is a great diversity of opinion.
Before discussing the nature of the ground moraine, however, it will be
necessary to say something about the glacier as an originator of detrital
material, a subject in regard to which opinions differ most widely, some
geologists looking upon glaciers as mighty erosive agents, and ascribing to
them nearly all that has been done to give the earth's surface its present
form, while others take quite an opposite view.

In regard to ordinary morainic material, there can be no doubt that the
glacier is simply the carrier, and not the originator. As to what goes on
above the sm-face of the ice there is no difficulty in getting at the facts; that
which is done under its concealing cover is mucli less satisfactorily made out.
And it must, in the first place, be called to mind that what takes place under

8 GLACIAL AND SURFACE GEOLOGY OF THE PACIFIC COAST.

the glacier is the joint result of ice and water action, and much of that which
is done under the ice by water could be done, and is so, on an immense
scale, equally well without the ice. There are, it is true, some geologists so
prejudiced in flivor of glacial erosion, if the expression may be allowed, as to
claim that all fine detrital material is the result of ice-action. Some even
go so far as to say that without glaciers we could have had no soil, an idea
which leads to the inference that the entire earth must at some former time
have been covered with ice, since there is no zone or region where deep
deposits of finely coniminuted material are not found. Indeed, the mass
of facts which oppose any such theory as this is so great, that it is not
necessary to occupy time in discussing the matter.

Ice, per se, has no erosive power. If the glacier were frozen to its bottom,
find could then be made to move, it would, no doubt, tear away the project-
ing edges of the rock masses on which it was resting; but it is a joerfectly
well established fact that glaciers are not frozen to their beds. The glacier
is snow which has been converted into ice by water, and without the latter
the former cannot come into existence. The ice being permeated with
water acts as a flexible body, taken as a whole, although in its parts it is
not. By virtue of this condition it adapts itself to the channel through
which it has to pass, bends ai'ound angular projections, rises over elevations,
turns sharp corners, narrows and widens again and again, and comports itself,
in short, just as we should expect a soft flexible body to do in passing over a
hard inflexible one. The proof of this statement is to be found in the ex-
amination of any extensive mountain chain which has been formerly jiartly
occupied by glaciers and from which they have since disappeared. No chain
offers a better chance for an investigation of this kind than does the Sierra
Nevada, as will be seen further on in this chapter. The recent shrinking of
the Alpine glaciers has laid bare large surfaces which but a few years ago
were covered with ice, and where the condition of the surface imder the
former glacier may be studied with the greatest fiicility. Nowhere, in any
such region denuded of its former icy covering, will it be found that the
glacier has had any power to cut through an obstacle so as to form a channel
with vertical, or nearly vertical sides, as water often does. The whole form
of the Alpine valleys is proof of this, for all will admit that if the ice which
once filled many of these up to a higher level than it now does had such an
erosive energy as is attributed to it by some geologists the section of those
valleys must have been quite different from what it is at present. Had ice

INTRODUCTORY : ICE NOT AX EROSIVE AGENT. 9

a peculiar erosive power, the bottom and the sides of the valleys through
which former glaciers have passed would exhibit some peculiarities of form
iudicatinu; that the work done below the level of the surface of the ice was
of a different character from that done above that level. But, in point of
fiict, on examining any valley once partly filled with ice, it will be found
that there is no such essential diffei'euce. No change of form can be ob-
served at the former line of the ice. Aside from the morainic accumulations,
there is nothing to prove the former existence of the glacier except the
smoothed, polished, or roimded surfaces of the rocks, which have no more to
do witli the general outline of the cross-section of the valley than the marks
of the cabinet-maker's sand-paper have to do with the shape and size of the
article of furniture whose surface he has gone over with that material.

Admirable instances of the difference between the erosive action of water
and that of ice may be seen in several of the valleys of the Bernina group,
in the Upper Engadine. Near Pontresina, for instance, there is a rise in the
bottom of the valley of between one and two hundred feet over which the
Morteratsch glacier once passed without eroding it away. Since the glacier
disappeared, the stream issuing from the ice, the end of which is now almost
three miles above Pontresina, has cut a gorge through the elevation in
question, which gives the stream a channel with nearly continuous grade,
and hemmed in by almost vertical walls. The same thing may be seen in
the Val de Fex, which leads down from the glacier of that name to tlie
village of Sils, a few miles soutliwest of Pontresina. It is manifest, in both
these cases, that the ice for a long time rose over an obstacle which was in
its path, without the power of removing it ; but that the water has quickly
sawn itself a passage through the same, aided by the peculiar lithological
character of the rock.

The most characteristic if not the most important work done by ice is that
which it effects on its rocky bottom by means of the detrital material which
has been carried down by water from tlie surflice of the glacier. The icy
mass moving over its bed smooths the edges of its inequalities by contiiuially
forcing fragments and particles of rock over them. Such smoothed surfaces
arc often found to be covered with fine lines or grooves, running, on the
whole, parallel with the course of the glacier. These striated surfaces, which
are so well known that they need not be described, are a peculiar result of
the movement of the glacier, and their existence is in most instances accepted
as positive proof of the former presence of ice.

10 GLACIAL AND SURFACE GEOLOGY OF THE PACIFIC COAST.

It is a mistake, however, to sujipo.se that striated surfaces cannot be pro-
ducerl by dr>j ruhhiny, or friction of surfaces against each other without the
aid of ice or water. Every mining geologist knows from his daily experience
that beautifully striated and polished surfaces have been produced in abun-
dance by the sliding of portions of the vein material against its walls, and that
this has often taken place where the amount of motion must have been very
small, the immense pressure being sufficient to bring about the result, even
when the distance over which the surfaces have moved cannot have ex-
ceeded a few inches. Excellent imitations of glacial striation are produced
by the passage of heavy vehicles with locked wheels over rock surfaces.
Pebbles also may be smoothed and striated by dry motion, provided they
are fixed in their places while the motion takes place. Where heavy rock
slides or avalanches have occurred, the bottom may occasionally be observed
to be not only striated, but even deeply grooved. It is decidedly unjustifi-
able in the geologist to presume on the former existence of ice at any epoch
or in any region from the occurrence of isolated smoothed and striated
boulders or pebbles in the rock masses. Only by careful comparison of all
the phenomena taken in their ensemble, over a considerable area of surface,
can the former presence of ice be clearly established in a region where the
present conditions are not such as themselves to throw light on the matter.
For instance, the finding of an occasional striated boulder in a conglomerate
of Devonian, Carboniferous, or Permian age would certainly not justify the
geologist in inferring that glaciers must have been in existence at the time
such rock Avas deposited.

As a consequence of long-continued crowding over the surface of the icy
mass, which carries more or less detrital material imbedded in it, the project-
ing edges of the rocky strata gradually lose their sharpness, and become
worn into those rounded forms to which the term roches moutowiees is com-
monly applied. This peculiar kind of surfiice is easily recognized by an
experienced observer. But there are certain rocks which assume forms very
closely imitating those produced by ice. Much granite, for instance, has a
concentric structure, causing it to break under the influence of ordinary
meteorological conditions into spherical forms, and to weather in masses with
rounded surfaces, very much resembling the roches moutonnecs. Want of
knowledge of those facts has led to many mistakes of this kind, especially in
the Sierra Nevada.

The conclusion to wliich the writer has arrived, after much examination

INTRODUCTORY : ICEBERGS AND THE ICE-FOOT. 11

of regions of present and former glaciation, is, that glacier ice has but little
erosive power, and that the so-called "ground moraine" is an appendage
of the glacier which is neither characteristic nor important. The present
shrinking of the Alpine glaciers shows that there has been usually but little
detrital material under them ; and this has resulted not so much from the
ice as from the water, which everywhere acts jointly with the ice in doing
its work ; indeed, the latter eifects nothing absolutely characteristic, except
the production of large areas of polished rock surfaces etched with fine
parallel striations, a result which water alone is unable to bring about.

The action of icebergs in regard to striation of rock surfixces, and more
especially the transportation of detritfil material, is a subject of interest in
this connection. From the very beginning of the discussions on these sub-
jects tiiere has been a marked amount of discrepancy of opinion in regard to
the relative importance of glaciers and icebergs as geological agents, and
as to the exact nature of the work done by each. Icebergs are born of
glaciers,* so that the connection between the two is necessarily an intimate
one, and the former may be said in their new condition to be simply floating
glaciers. That the iceberg when detached from the glacier is often heavily
loaded with detritus is a fiict well known from abundant observations, and
one which might be inferred without observation from the very nature of
the case. That these floating detritus-carriers are able to transport their
burdens to great distances, as they are moved by the winds and ocean curi^ents
into which they are borne, is also clearly imderstood. That such detritus, as
accumulated along the route of the icebergs, will have a morainic character,
— that is, will be angular and irregularly mixed, — is easily recognized. But
no true moraine will be formed by icebergs, because they are not held to one
exact course, as is the glacier enclosed between its rocky walls ; while there
must also be great irregularity in the distribution of the material left by
icebergs, because they float with irregular course, according to the varying
nature of the winds and currents, and because they are more or less rapidly
melted, according to their size and their exposure to meteorological con-
ditions which in their very nature are unstable.

The so-called "ice-foot" also acts, to a considerable extent, the part of the
glacier, lor it receives, when suitably situated, a considerable amount of
falling detritus, and when loosened by the summer's heat floats oft' and bears
this material away, iceberg fashion.

* The formation of an iceberg is familiarly known in Greenland as tlie "calving" of tlie glacier.

12 GLACIAL AND SUEFACE GEOLOGY OF THE PACIFIC COAST.

All floating masses of ice haviiiQ- fraorments of rock frozen into them are

O ij CD

able to striate and smooth the projecting surfaces of the rocks with which
they may be brought in contact. The work which they thus clo is closely
analogous with that of the true glacier ; but a comparison of all the con-
ditions of any locality where such striations occur can hardly foil — in most
cases at least — to settle the question of the nature of the agent involved.

The occurrence of work done by icebergs of course necessitates the former
presence of the ocean, since the glacier must descend to the sea-level before
it can give birth to an icebero-. That larsje bodies of fresh water mio-ht,
however, to a certain extent play the part of the ocean as floaters of ice
masses, can hardly be denied.

The abundance of lakes in certain regions which have been formerly
covered with glaciers is looked upon by some geologists as a proof of the
powerfid erosive action of ice ; and there are those who consider that all or
nearly all lakes owe their origin to this cause. This seems to the writer an
entire misconception of the nature of the work done by glacial agencies, and
in support of tliis opinion the following considerations are offered. In the
first place, however, it may be mentioned that there is one class of lakes in
resjrard to whose glacial ori2:iu there can ]je no mistake. These are the so-
called " moraine lakes," or collections of water formed behind a terminal
moraine, left on the retreat of the glacier, and barring the valley more or
less perfectly. The tendency of the streams issuing from such lakes is to
wear away the opposing detrital mass, and thus to allow the superfluous
water to escape ; hence moraine lakes usually disappear in time, after the
glacier has retreated sufficiently fiir, or disappeared altogether.

The existence of lakes depends, in most cases, on a somewhat complex set
of causes. The principal conditions influencing their formation are such as
are cormected with the orography and the climatology of the region where
they occur; but the nature of the rocks also plays an important part in their
formation. If tlie orographic conditions are favorable, and the rainfall is not
overbalanced by the evaporation, lakes will occur in greater or less abun-
dance, and of greater and smaller size, in strict accordance with the character
of the topography of the locality. Central Africa is an excellent illustration
of the rationale of the formation of large lakes in a region of excessive rain-
fall, favored by suitable orographic conditions. The number of those great
bodies of water is not yet known, nor have those which are known been
much explored ; but it is clear that within an area occupying a length of

IXTEODUCTORY : THE OCCUREEXCE OF LAKES. 13

over fifteen degrees north and south, and a nearly equal breadth east and
west, within the tropics, there are many lakes of great size, at an elevation
of 3,000 feet and over above the sea-level. The region is one of great pre-
cipitation, and the orographic structure of the continental mass is eminently
favorable to the formation of lakes, it being an elevated and comparatively
level plateau surrounded by a rim of mountains. But there is still another
reason for the existence of these great bodies of water. The rock is largely
granitic, or crystalline in texture, not taking up a large percentage of the
rainfall, but being almost impermeable. Most of these lakes are, in all prob-
ability, shallow ; and their area is known to be quite variable, their dimen-
sions changing with the season and with the succession of seasons.

Turning to equatorial South America, we find a complete contrast to the
conditions just noticed as occurring in Central Africa with regard to the
existence of lakes. Equatorial South America is drained by a large river, —
the larsrest one in the world, — and .so thoroughlv drained that there are no
important lakes at all in the whole of its basin, and but few small ones, ex-
cept such as have a "bayou" character, and are evidently formed l)y the con-
stant shifting of the channel naturally connected with the flow of a mighty
river, with immense tributaries, subject to periodical inundations, through an
almost level region. Of such lakes there are doubtless an abundance, but
they are too small to be exhibited on our ordinary geographical maps, and
their origin cannot be for a moment misunderstood. The orographic cause
of this condition of things, offering such a contrast with the lake features of
Central Africa, becomes evident on an examination of the structure of the
reo-ion. While in Africa there is a rim all around the table-land, or elevated
basin forming the interior of that continent, there is in South America no
eastern raised border ; but, on the other hand, a gradual inclination of the
surface from the crest of the Andes to the Atlantic. Besides, the rocks over
by far the larger part of the basin of the Amazons are of a kind easily retain-
ing large quantities of water, and not granitic or crystalline.

There is probably hardl_v a single geologist among those most inclined to
magnify the Avork of ice who would ascribe a glacial origin to the lakes of
Central Africa, lying as they do within the tropics ; but there are other
lacustrine districts in the temperate zones in regard to which there would be
less unanimity of opinion.

There are two especially interesting and important lake regions, besides
that of Central Africa, to whicli allusion has already been made : one of

14 GLACIAL AND SURFACE GEOLOGY OF THE PACIFIC COAST.

these is in North America, the other in Europe. The former is a region
of both great and small lakes ; the latter of small ones exclusively. The
North American lake system is the most extensive one in the world at the
present time, although it may possibly have been surpassed, at a not very
remote geological epoch, by that of Central Asia.

The geographical position of the region of country occupied by the great
system of North American lakes is pretty well known, especially in its south-
ern portion, although there is no map on which anything like the entire
number of these bodies of water is shown ; while for most, even of the largest,
at best but a rough approximation to their outlines can be given. It may be
well, therefore, to call the attention of the reader to the foct that, all along
a line stretching in a northwesterly direction from Lake Superior to the
Arctic Ocean, there are not only numerous, but almost innumerable, bodies
of water, several of which are but little, if at all, inferior in size to even the
largest of our so-called " Great Lakes." The number of lakes in this region
is quite unknown ; but a belt of country 2,000 miles long and fully 500 wide
is a labyrinth of them, and they are of all dimensions, from mere ponds to
bodies of water hundreds of miles in circumference. So too in the opposite
direction, or along the range of the Laurentian Mountains, northeasterly
from Lake Huron towards Labrador, there are unnumbered expanses of fresh
water, mostly of moderate size compared with the Great Lakes, but many of
them having a considerable area. These Canadian lakes have not yet been
accurately mapped; but more than a thousand of them had, some fifteen
years ago, been more or less explored by the Geological Survey. In fact,
tlie whole region northwest of the St. Lawrence, as fiir as Hudson's Bay,
is covered with lakes and lake-like expansions of the rivers, so that there is
free access by canoe to every part of the countiy, with occasional portages,
or " carries," around the rapids in the rivers.

In this lake region may be included a large part of Maine and the north-
ern portion of New Hampshire, as well as of Vermont and Northeastern New
York.

In striking contrast with what has been stated above, we find the region
immediately south of the Great Lakes to be one almost entirely destitute of
lakes. Everywhere, from the water-shed separating the waters fiowing into
the Susquehanna and Ohio from those running northwards, as far south as
the Gulf of Mexico, there is an almost entire absence of lakes; indeed, it
would be hardly i)Ossible to imagine a greater contrast, in this respect, be-

IXTRODUCTOKY : THE OCCUraiEXCE OF LAKES. 15

tvveen two adjacent regions of country, and it will be desirable to inquire into
the causes which have brouo-ht about this curious condition of thino-s.

The causes which have produced this extraordinary complex of lakes in
the northeastern region of North America are by no means simple. They
are partly orographic and geological, partly climatological. Ice has also
played a part in this work, although, as it appears to the writer, quite a sub-
ordinate one.

The orographic element in the work will be easily recognized from an
inspection of a good map of North America. If two parallel lines be drawn,
about 500 miles apart, one touching Georgian Bay of Luke Huron, tlie other
the southwest corner of Lake Michigan, and prolonged in a northwesterly
direction to the Arctic Ocean, the great series of lakes belonging to the sys-
tem will be found lying within the belt of country thus limited. These lines,
however, are parallel with the general trend of the adjacent portion of the
Cordilleras, showing at once the orographic character of the belt of depres-
sions. Furthermore, the direction of the axes of the larger lakes within this
area is usually at right angles to the line of trend mentioned, which fact
is another important guide to the character of the forces by which these
depressions have been produced. Again, the connection of the orographic
character of the lake belt in question with its geological position is most
marked. This great chain of lakes, as will be apparent whenever a good
geological map of the region shall have been published, lies on and in the
neighborhood of the belt separating the modern geological formations which
belong to the Rocky Mountain uplift, from the Azoic or older crystalline
schists and granites, forming the mass of the Lauren tian Range. This belt is
made up of Palaeozoic rocks, and it is in these that the large lakes are chiefly
developed. The moment that we pass from the older rocks on to the more
recent, in going westward, Ave at once leave the lacustrine region behind.
A portion of this belt is depressed beneath the sea-level even, Lake Superior,
the surface of which is 609 feet above that line, being in places over 1,000
feet in depth. This lake occupies a synclinal depression of the Palaeozoic
rocks, just along the edge of the Azoic Series.*

Lake Huron is similarly situated, its northern edge abutting against the
older crystalline rocks. In tact, all the Great Lakes, including those of
British America, from Ontario arouml the great sweep of 3,000 miles to the
Arctic Ocean, are in a similar geological position, occupying a depressed

* As long since shown liy Fostui' and Wliitiiey. See Ri'iiort ou tile Geology of Lake .Superior, Part II. ji. 117.

16 GLACIAL AND SUEFACE GEOLOGY OF THE PACIFIG COAST.

area along the base of the Azoic nucleus of Northeastern America, an area
which has not partaken of the uplift hy which the Appalachian chain has
been foi'nied, or of that much more recent one which has given rise to the
system of the Cordilleras. These lakes are all either entirely included
within the Palaeozoic, or else partly in that formation and partly in the
Azoic, and in no case do they extend into the more recent groups of strata
which are found, on going south or west from the older rocks, to overlap
these latter formations. The orographic character of these large bodies of
water is therefore the most marked feature of their occurrence, and there
is nothing about them which renders it necessary, or even possible, to refer
their origin to glacial erosion ; there is nothing in their position or the di-
rection of their axes which in any way lends countenance to the idea of
their basins having been scooped out by the action of ice.

Climatological causes act together with oi'ographic ones in the formation
and maintenance of the lakes in question. The depressions of the surface
are kept filled by the annual jirecipitation, which more than overcomes the
evaporation ; for the region is one of considerable rainfall, and of pretty
high northern latitude. The surplus water is chiefly carried off by two
mighty rivers, the St. Lawi^ence and the Mackenzie, of which rivers all the
Great Lakes — with the exception of Winnipeg and WinneiDCgosis — are
expansions.

Very different from this is the condition of things in the so-called '' Great
Basin." Here was once a region of large lakes, many in number, and some
of them little, if at all, inferior in size to the Great Lakes themselves. But
the climate has changed ; the lakes have shrunk up and nearly or quite dis-
appeared, and in most cases there is nothing left but old lake bottoms, cov-
ered with alkaline or saline deposits in the dry season, and with mud or
shallow water in the wet. No one could by any possibility assign any other
than an orographic origin to these lake-basins ; that they are not now filled
with water is due to climatological causes, to the nature of which reference
will be made further on.

That lakes of large area are essentially nothing more than portions of the
earth's surface depressed by crust movements below the genei-al level of
drainage, and kept full and running over by the excess of precipitation over
evaporation, seems to be perfectly clear ; to admit that they are the result
of erosive action would require us also to believe that large, nearly closed
seas, like Hudson's Bay and the Mediterranean, are areas of erosion ; and it

INTrxODUCTORY : THE OCCUERENCE OF LAKES. 17

would be only a logical sequence of ideas to declare the ocean itself to have
been washed out from the land, and the continental masses built up from the
material thus eroded.

The orIi>in of the smaller lakes with which certain areas of the earth's sur-
face are profusely dotted is a problem much more difficult than the one just
discussed. As already mentioned, there are two regions in which small
lakes occur in the greatest abundance. One is the country north of the St.
Lawrence, a district of both large and small bodies of water ; the other, Fin-
land. Such small lakes are almost invariably quite shallow ; it can only be
a very peculiar and highly exceptional condition of things which can produce
a very deep lake of small area. The essential facts influencing the forma-
tion of small lakes arc, a nearly level surface of the region in which they
occur, and an underlying rock formation impervious to water.

Both Finland and tiie Canada lake region are underlain by crystalline
rocks, which are almost impermeable. If we follow on the map the outlines
of the district in Northeastern America where lakes abound, we find that
these are left behind as soon as we pass out of the domain of the crystalline
or metamorphic rocks into that of stratified and permeable formations. For
instance, the contrast between the frequency of lakes in Northern Wisconsin,
a region of Azoic rocks, and the central and southern portions of the same
State, where stratified sandstones are the predominating formation, is most
striking. The peninsula of Southern Michigan, and that triangular portion
of Canada lying between Lakes Erie and Huron, offer similar contrasts when
compared with adjacent regions of impermeable rocks. Minnesota and the
adjacent Territory of Dakota also afford an excellent illustration of the limi-
tation of lakes to regions of rocks whose te.xture is impervious tc water.

That level regions of country should be more favorable to the development
of small lake basins than the flanks of mountains, is easily understood. A rapid
descent gives the streams great erosive power, and they are enabled to wear
away their beds so as to drain depressions which would othei'wise be partly
or wholly filled with water. Given a level region underlain by impervious
rocks, the precipitation being moderately in excess of the evaporation, and
it is manifest that the water must stand upon the surface over areas of
greater or less magnitude, unless there can be some reason assigned why
that surface should be absolutely level. Deposits laid down under the ocean
are more likely to be evenly distributed than those which result from fluvial
action, because the former are the result of agencies working on a grand

18 GLACIAL AND SURFACE GEOLOGY OF THE PACIFIC COAST.

scale, while the latter are more local in character. Hence, when such sub-
raarine deposits are raised above the surface, and in that elevation have been
not at all or only very slightly disturbed, the drainage of the uplifted region
will be eflfected simply by rivers, there Ijeing few depressions to be filled
with the excess of precipitation and thus to become lakes. Highly meta-
morphic rocks, on the other hand, are not only by their nature impervious
to water, but they must have been left, after passing through the various
stages of chemical change and orogi-aphic displacement, with an uneven siu'-
face, suited to give rise to collections of standing water. This result, under
suitable climatological conditions, cannot fail to take place, unless the irregu-
lar surface is afterwards subjected to some erosive agency which smooths
it over and reduces it to one uniform level. Erosion of this kind can,
however, but rarely take place, for the ordinary denuding agents are quite
as likely to deepen the previously existing depressions as to obliterate them.
A level surface may indeed be produced in such cases by the entire surface
becoming uniformly covered with detrital material ; but this can only ])e
effected by a submergence of the region beneath the sea, during a long-
period and under favorable conditions.

Keeping the above considerations in view, it will be evident why regions
like Canada and Finland are covered with a network of small lakes. The
countries in question are underlain by impermeable rocks, which have dur-
ing an immense period been subjected to subaerial erosion. The overlying
detritus is usually quite thin, and only here and there accumulated in heavy
masses. It consists largely of gravel, but has enough clayey material con-
nected with it to ffivor the formation of lakes and ponds. Water has a
tendency to accumulate in the depressions of the solid rock, and this ten-
dency is farther aided by the peculiar manner in which the eroded materials
have been scattered over the surface. The impervious character of the
imderlying rock, the thinness and irregular distributiou of the overlying
detritus, and the general uniformity of level of the region, — these are the
agencies which have given rise to the multiplicity of lakes in the countries
in question.

Thus we see why, as soon as we leave the region of crystalline rocks,
either in Northwestern Russia or Northeastern America, we leave the lakes
behind us, as already indicated. That glacial erosion is not the cause of the
sudden change in this respect, is shown clearly enough by the fact that wo
pass at once, in the midst of an area formerly covered with ice, as would be

INTRODUCTORY : ORIGIN OF FIORDS. 19

admitted by all glacialists, from a region of lalces into one totally destitute
of them, the underlying rocks having changed their character, while the
proofs of the former presence of ice remain the same.

Illustrations of the occurrence of lakes of various origin on the Pacific
Coast will be given in describing the glacial features and surface geology of
that region. Intimately related to the topic just discussed is the subject
of the formation of fiords, to which in this connection a few pages may be
devoted.

It will appear evident, from what has been said in the gravel volume in
regard to the depth and number of the canons on the west slope of the Sierra,
that if the land were submerged or the sea-level raised a few hundred feet,
not only would the Sacramento and San Joaquin Vallej' be covered with
water, but the coast-line on the eastern side of this large inland sea Avould
have an extremely irregular outline, being deeply indented in many places,
these indentations having very precipitous sides, and offering in every
respect a striking analogy with the so-called fiords of the Scandinavian
Peninsula. Looking along the present coast of the Pacific side of North
America, we find a line remarkably free from indentations until we reach
the vicinity of Vancouver Island, when we come suddenly upon a region of
deep inlets and numerous outlying islands of large and small size, very in-
completely represented, however, on our ordinary maps. Good harbors are
as abundant in this region as they are few and f;ir between to the south.
Turning our attention to other parts of the world, we find the same remark-
able difference between the coast-lines of different rey-ions. Sonth America
strikes us at once as being extremely deficient in indentations affording
good harbors, from its northern extremity almost to its southern. Africa
wants them almost entirely in every portion of its outline. This peculiar
frequency of fiords or deep indentations of the coast has been the subject
of considerable discussion; yet, as there are difficulties in regard to their
origin and mode of occurrence which have not been removed, it will per-
haps be worth while to endeavor to throw some additional light on the
subject.

The mere recapitulation of the regions of fiords and deeply indented coasts
will show at once that they are almost exclusively confined to high latitudes,
both northern and southern. That they ai'e much more extensively devel-
oped north of the equator than south, is very naturally accounted for by the
fact that there is so little land in high latitudes in the southern hemisphere.

20 GLACIAL AND SUEFACE GEOLOGY OF THE PACIFIC COAST.

Only the southern end of South America and the west side of the southern
extremity of New Zealand on that side of the equator can be included in the
list of typical fiord regions. The Atlantic coast-line of the Scandinavian
Peninsula, the west coast of Greenland, and perhaps also its east coast, — of
which little is known, owing to its inaccessibility, — the northwest coast of
North America, above Vancouver Island, — these are typical fiord regions.
In lower latitudes, the east side of the Adriatic Sea, especially its northern
portion, as well as the Grecian Peninsula, also belongs decidedly to fiord
regions, but does not exhibit these indentations on as grand a scale as the
first mentioned.

The first thing which may be noticed in regard to indented coasts is, that
they are usually coasts rising precipitously from the water, or such as are
bordered by mountains or the descending edges of high plateau regions. In
fact, a mountainous background is an essential part of a true fiord coast. A
glance at the maps will show this to be a fact. But it is not Ijy any means
every mountainous coast which abounds in fiords. For instance, the stretch
of shore line from San Francisco south for several hundred miles is bordered
by a high mountain chain, but possesses hardly a single indentation, a want
most seriously felt in its relations to commerce. The whole coast of South
America is another excellent illustration of this ; it is, however, not to be
denied that the Andes do not rise immediately from the coast, although they
may seem to do so to those looking at the ordinary small-scale maps.

The evident reason for the association of mountainous coasts with fiords is,
that these peculiar indentations represent an amount of erosive action which
can only be had in a high mountain range. Two things are required for the
erosion of these deep gorges which under suitable conditions become fiords.
These are : first, a large precipitation, or a great deal of material with which
to do the work ; and, second, a rapid fall of the surface, which gives the
power by which this material acts. All great mountain chains have their
sides deeply furrowed with steep valleys, gorges, or caiions. Let the Alps, or
the Himalayas, or any other great range, be sunk to a suitable depth beneath
the water, and the result will be that the central dominant range will project
above the surface of the water with an irregular and deeply indented coast-
line, while there will be occasional; and in some cases numerous, groups of
islands in the vicinity of such a coast. Let any one study the Norwegian
coast, for instance, and he will see at once tliat what are now fiords would
become mountain vallej's if the region were elevated so as to bi'ing the bot-

IXTRODUCTOIIY : FOIOrATIOX OF FIORDS. 21

toiu of these fiords above the surface of the water, while certain points higher
than the adjacent surface, but now deep beneath the water, woukl appear as
islands. Hence almost all fiord coasts are accompanied by outlying fx-ag-
ments of land of greater or less size, as is well illustrated on the Norwegian
coast; and also, in a higher degree, by the shores of British Columbia, from
Vancouver Island north.

In considering the nature and origin of fiords, we are led irresistibly to the
conclusion long- since enunciated by Professor Dana, namely, that fiords are
evidences of subsidence ; the regions where they occur are those whei-e a
high mountain range has become partially submerged, so that the bottoms
of the deep valleys of erosion are now occupied by the sea.

It has been claimed by some writers on this subject that the occurrence of
fiords in high latitudes is proof that the excavation and erosion which they
indicate to have taken place has been the work of ice. All that we have
observed, however, with regard to the amount of erosion which ice is capable
of effecting, leads us to infer that glaciers have had little to do with the mat-
ter ; unless it be that, to a certain extent, the filling by ice of vallej's already
formed has prevented their being afterwards occupied by the detrital ma-
terials which would necessarily accumulate in a mountain valley where the
slope was insufficient to give to running water the power to remove such
detritus, or where, from climatological changes, the amount of precipitation
has diminished, and thus the erosive action decreased, so that the gorges
could no longer be swept clean of the detritus carried down into them from
their borders of more or less precipitous rocks.

The fact that the fiords are chiefly on the western side of the continents
has been insisted on as connecting their origin with the occurrence of areas
of great precipitation, the sides of mountain ranges in the extra-tropical lati-
tudes which are exposed to the return trade-winds being likely to receive a
much greater rain and snow fell than the opposite or eastern flanks of the
same chains. The abundant precipitation in the form of rain giving rise to
the deep gorges on the mountain sides which are afterwards to be converted
into fiords by the sinking of the region, the continuance of the same increased
precipitation in the form of snow, under those changed climatic conditions
which will be explained further on, causes these precipitous valleys to be-
come filled with ice, which carries the detrital material away on its surface,
and deposits it sometimes at a great distance from its source, as the icebergs
formed from glaciers coming down to the sea on the west coast of Greenland

22 GLACIAL A^'D SUEFACE GEOLOGY OF THE PACIFIC COAST.

are now doinf on a grand scale. All the conditions required for the forma-
tion of fiords are illustrated by the phenomena displayed on the coast of the
Scandinavian Peninsula, as will be noticed further on.

The facts, then, connected with the occurrence of deeply indented coasts
and fiords are briefly as follows : A coast-line may be very irregular and
deeply indented where the adjacent land is low and level, as, for instance,
the east side of Denmark. This is simply the result of the wearing away
of the easily yielding land by the ocean. Such coasts are very different in
character from tliose of typical fiord regions. These must be connected
with high mountain ranges, and the fiords are the result of erosion of their
sides by water. Hence they occur chiefly in regions of large precipitation.
But the gorges thus eroded do not become fiords until subsidence of the
range has brought them down into such a ])Osition that the water of the ocean
can enter and partly fill the precipitous valleys which have thus been cre-
ated. Should the range remain stationary in elevation after the decline of
the period of greatest precipitation, the eroded valleys would gradually Ije-
come filled with detrital material, unless protected from this by becoming
partly filled with ice at a later period, in consequence of a change of climate,
the nature and cause of which will be explained further on.

A depression of the crust appears, for some reason not yet explained, to
have been going on during the most recent geological ages in high northern
latitudes. Hence we find that peculiar sequence of conditions necessary for
originating truly typical fiord-coasts to have occurred only in a few regions,
although approximations to these peculiar indentations are found in all lati-
tudes and in various countries.

It must be admitted, however, that erosion has not done all the work of
forming the precipitous valleys which have become converted into fiords.
The rano-es in which these grand gorges and transverse cuts occur have been
elevated by internal forces ; it is highly improbable that the great masses of
rock were brought into their final position with smooth, vmbroken surfaces.
On the contrary, the uplifted crust must, in many places at least, have been
broken, shattered, and left with the most irregular outlines. The features
of the country have thus been rough-hewn, and the work of water has been
carried on in strict subordination to that previously effected by mightier and
deeper-seated causes. Such is the opinion of the present writer, although he
is Avell aware that, as already suggested, there are other geologists who think
very differently, and who, in point of fact, consider that nearly all the sculp-

GLACIATION OF THE SIERRA NEVADA. 23

turing of the earth's surface has been done by the agency of ice. The sub-
ject will, it is thought, receive some light from what has been stated in the
gravel volume with regard to facts observed in the Sierra Nevada and
elsewhere.

Section II. — Former Gluciaimi of the Sierra Nevada, of the Pacific Coast, and

of the Cordilleras in yeneral.

Some account may now be given of the facts which have been collected
during the progress of the Geological Survey of California in reference to
the former extension of glaciers over portions of the Sierra Eange, and to
these will be added such information as is in our possession, obtained from
various sources, about the development of the ice-period in regions adjacent
to the Pacific Coast, and in the Cordilleras generally. Brief statements of
the facts observed in the Sierra Nevada have already been published in the
Geology of California, Vol. I. ; and the object at present is to put these
and more recent observations into a connected form, so as to open the way
for a discussion as to their importance, both in reference to the distribution
of surftvce detritus in the Sierra, and to the theories of former ice extension
generally.

The first fact to be noticed is the great ease with which the evidences
of former glaciation in the Sierra Nevada are obtained. There is nothing
doubtful aljout the matter; once one enters upon a formerly glaciated region
thei'e is no possibility of mistaking the origin of the phenomena presented
to view. Polished and scratched surfaces, smoothed and rounded ledges
[roches mouionnees), transported boulders, and, above all, moraines of various
kinds, are all recognized with the greatest ease by the observer, making a
combination of occurrences which no one familiar with glacier regions could
for a moment hesitate to refer to their true cause. The difficulty has been,
however, that a good deal has been published by various persons who
were quite unacquainted with glacial work, and who indeed in some cases
had not had the advantage of a previous training as observers in any depart-
ment of geology ; and these writers have brought confusion into the .subject
by referring many phenomena to the effects of ice where there was by no
means any sufficient authority for such reference. Some have even gone .so
fir as to sprinkle livino- n-laciers all over the Sierra, and others have ascribed
to ice the principal share, or even the exclusive agency, in forming and fash-

24 GLACIAL AND SURFACE GEOLOGY OF THE PACIFIC COAST.

ioning the grand peaks and domes of the Sierra. There are few parts of
the world where the dynamical agencies of ice in past times can be more
conveniently and profitably studied than in the region in question; but it is
very desirable that such study should not be entered upon with precon-
ceived theories, and that it should have been either preceded or at least
afterwards supplemented by analogous studies in other regions of present
extensive glaciation, like Switzerland or Norway. Such study on the part
of some of those who have given their opinions with the greatest fluency
in reference to supposed glacier work on the Pacific coast would perhaps
have made these writers a little more cautious in advancing their crude and
often utterly absurd theories.

The reason of the very plain and obvious nature of the former glacier
work in the SieiTa is due in large part to the very recent date of its occur-
rence ; and this fact links itself unmistakably with another important one,
namely, that the glaciation of the range is Jibsolutely and entirely in har-
mony with its present topography. The whole body of fiicts collected hy
the Geological Survey shows most clearly that there has been no essential
change in altitude of the formerly glaciated regions since the ice disap-
peared ; and, still further, that all the features of the surface — valley, gorge,
caiion, cliff, dome, ridge — remain just as they were when the climatic con-
ditions changed so as to bring about the shrinkage and final obliteration of
the once extensive ice-masses. It is even clear that the volcanic fires of the
Sierra were entirely spent before the glaciation of the range took place. In
short, the ice-pei'iod in California was the most recent of all the geological
phenomena there exhibited ; and, as will be clearly shown, it cannot be con-
sidered to have been removed by any but a very moderate amount of time
from the actual present.

In commencing a rapid review of the former distribution of glaciers on the
Sierra, we may begin by referring to the well-known fact, that the range
sinks in general elevation as we proceed northward from the culminating
region in lat. 36' 30'; southward from this the range also breaks ofT quite
abruptly. Glacial phenomena are therefore cut off altogether, to the south
of 36°, by the rapid decrease of the range in altitude, combined with constant
diminution in latitude. To the north the falling off in altitude is partly
compensated by the more northei'ly position, so that we have a belt along
the Sierra of from three to four degrees in width, where the phenomena of
ancient glaciation are chiefly displayed.

GLACIATION OF THE SIERRA NEVADA. 25

The most striking feature in this glaciated region is, that the extent of the
former glaciers Avas strictly in harmony with that of tlie elevated reo-ion
which was the field of supply for the ice-stream. A large area, at a suffi-
ciently high elevation, where the snow could collect and hecome consolidated
into ice, gave birth to a proportionately large glacier, just as now in the
Alps the Aletsch and the Corner glaciers, and the Mer de Glace, have at their
heads the largest amphitheatres, or cirques, and are consequently the longest
and best developed glaciers of the Swiss momitains.

Before proceeding to a description of the phenomena of extinct glaciation
in the Sierra Nevada, it is desirable to say something in regard to the present
distribution of snow and ice in that range, and in the Cordilleras generally.
And in the first place it may be stated that there are no glaciers at all in
the Sierra Nevada proper, and none in the Great Basin or Rocky Mountain
ranges, at least south of the parallel of 42°. With the exception of some
recent discoveries said to have been made in 1878, in the Wind River Range
(about lat. 43°), by tlie U. S. geological surveying parties, of which no
definite account seems as yet to have been published,* it may be stated that
there are no proper glaciers anywhere within the limits of the United States
(Alaska not included), except around the great isolated volcanic cones of the
Pacific Coast. There .are certainly none in the highest portions of the Sierra
Nevada or the Rocky Mountains, these most elevated regions having been
sufficiently explored to ascertain that fact. The Wind River Range and
the region adjacent to it is considerably inferior in height to the peaks and
valleys around the South Park and the upper part of the Arkansas River;
but the difference of four degrees in latitude more than counterbalances the
difference of elevation, as respects the conditions necessary for the formation
of glaciers.

The precipitation on the fianks of the Sierra Nevada is mucli larger on the
western slope than on the eastern, and it undoubtedly is considerably greater
near the summit tlian lower down on the slope. Unfortunately, statistics are
almost entirely wanting. It is well known, however, that the precipitation
is nearly all in the form of snow along the crest of the Sierra, and that it
falls in the winter months almost exclusively. Near the summit of the range
there is, in tlie sunnner, an occasional heavy thunder-storm, attended with a

* Nothing seems yet to liave been published in regard to these glaciers, beyond the statement, in the Preliminary
Report of the Field Work of the U. S. Geological and Geographical Survey for the Season of 1878, that " three
genuine glaciers were discovered ou the east base of Wind River and Fiemont Peaks." Dr. Hayden informed the
writer that the largest of these glaciei-s might be jierhaps a mile in length.

26 GLACIAL AXD SURFACE GEOLOGY OF THE PACIFIC COAST.

fall of rain, the quantity of which may in some rare instances be quite large.
Such events are not common enough to be allowed any weight as elements
in the climate. In the central portion of California snow only rarely falls in
localities lower than 2,000 or 2,500 feet above the sea-level. There are some-
times several years in succession when the portions of the Coast Ranges in
sight from the city of San Francisco, and from 3,000 to 4,000 feet in altitude,
are never whitened with snow ; and when this does occur, it is rarely for
more than a few days at a time. Yet there have been years when quite
heavy falls of snow have taken place, even in the valleys, in the immediate
vicinity of that city.

In the Sierra Nevada, although the different years are quite variable with
respect to the snow-fidl, it does not often happen that it is not large in the
higher portions of the range. In some seasons it becomes enormous, amount-
ing, as is stated on good authority, to more than sixty feet. Of course, even
in ordinary years, the accumulations of snow in the deep canons, and in other
sheltered places into which it is driven by the wind, are sometimes of great
thickness. As a general thing this snow disappears very quietly, in large
jDart by evaporation, and the rivers are not so much swollen by its melting
as would be expected. It is only when a heavy general snow-fall is suc-
ceeded by a warm rain, occurring over a wide area and extending to con-
siderable altitude, that such heavy freshets take place as that of the winter
of 1861-62, when a considei'able portion of the Sacramento Valley was
deeply flooded with water. During ordinary years the snow appears, as the
range is seen from a distance, to have pretty much disappeared by May or
June. But the crest of the Sierra is never entirely denuded of its snowy
covering, although at the end of a long and hot summer, following an un-
usually dry winter, it may seem to be so. In the sheltered nooks and deep
crevices, especially on the north side of the higher peaks, patches of consider-
able size will always be found. This is especially true for the higher portion
of the range, as far north as the north end of Lake Talioe. Beyond this, to
Lassen's Peak, where the highest passes are not much over 7,000 feet, and
the peaks between 8,000 and 0,000 in height, there is ordinarily but very little
snow left at the end of the summer. In Plumas County there were in 1866
only one or two of the highest points on which snow remained through the
entire summer, all having disappeared except a few small patches on the
northern slopes of the most elevated peaks. On Lassen's Peak, however,
quite large bodies remain permanently ; or at least have always been there

GLACIERS OX MOUNT SHASTA. 27

when this mountain, which is about 10,600 feet high, has been seen by the
Survey. These snow spots, the lowest of which hes about 2,000 feet below
the summit, have appeared of about the same size and form when seen in
different years during the summer months.

From Lassen's Peak as far as Mount Shasta there is no permanent accumula-
tion of snow ; but on the last-named grand volcanic cone, which is over 14,000
feet high, there seem to be alwaj's large bodies lasting throughout the sum-
mer, and extending down to points 6,000 or 7,000 feet below the summit.
In September, 1862, when the quantity for that year was at a minimum, the
cone of Shasta looked dazzlingly white at a distance, as seen from the south.
On approaching the mountain to within a few mile.s, the ridges and crests
between the ravines furrowing its sides were found to be bare ; and on
actuallj' climbing to its summit it seemed difficult to understand how, when
so much of the upper part of the cone was uncovered, it could appear, fifty
miles off", to be one unbroken mass of snow. This was the year following
a winter of extreme precipitation; and, judging from photographs taken by
Mr. Watkins in 1870, and from information received at various times,* there
have been seasons when there was much less snow on this mountain than
there was when we climbed it.

At the time Mount Shasta was ascended by the writer, in company with a
party of the State Geological Survey (September, 1862), nothing was seen or
known of the existence of any glaciers on or near this peak. The on\y ap-
proach to ice ob.served was near the summit, where a large, nearly level area
was found to be covered with snow, described in the account of the trij) after-
wards published as being " almost icy in texture," and intersected by crev-
ices from two to three feet deep.f This might perhaps pass as neve, but
could not by any possibility have been called a glacier. This ascent was
made on the southwestern side of the mountain. Later in the season Messrs.
Brewer and King, of the Geological Survey, continued the reconnaissance of
Sliasta by a journey along its northern base ; but still no glaciers were no-
ticed. Some years later, in 1870, Mr. King, in making a detailed examina-
tion of the mountain, discovered several large glaciers, of Avhich only a
preliminary account has been published, t

* Especially from Mr. J. H. Sisson, mentioned in Geology of California, Vol. I. p. 332, as residing near
the base of Shasta, and as having frequently acted as a guide to its summit.

t See Geology of California, Vol. 1. p. 340.

J A full report of these explorations of the Pacific Coast volcanoes by Messrs. King, Hague, Enmions, and Wil-
son has never been published. Mr. King gave a short account of liis investigations around Shasta in an article in

>

28 GLACIAL AND SURFACE GEOLOGY OF THE PACIFIC COAST.

It appears that circumstances were very unfavorable for the finding of
these ghiciers at the time when the party under the direction of the writer
ascended Mount Shasta. They were probably deeply covered with snow ;
but, even if they had not been, they might not have been observed, for soon
after reaching the summit, and while attending to the barometrical observa-
tions, clouds gathered so as entirely to obstruct the view down the slopes of
the mountain. There being no glaciers on the south side of the cone, it was
not supposed likely that there would be any on the other. According to
Mr. King's observations, however, an east and west line divides the mountain
into glacier-bearing and non-glacier-bearing halves. At the time of his visit
the snow masses were less than had ever been known before ; from the
earliest settlement of Strawberry and Shasta Valleys there had never been
such a complete denudation of the mountain. The photographs taken by
Mr. Watkins at that time show the southern side of the cone to be almost
entirely bare ; and it was from the southwest that our party, towards the
close of the season of 1862, ascended over a snow-slope at least seven miles
in leno;th.

Mr. King describes three principal glaciers, the largest about four and a
half miles in leno;th and two or three miles wide. He remarks as follows:
" We explored one after another all the canons, which, approximately follow-
ing the radius of the cone, are carved to a greater or less depth with the
lava-flows. From the secondary cone around to the eastern side of the main
mass are only occasional fields of snow and ice, — bodies of a thousand or
two feet long, usually quite narrow, and lying on the more shaded sides of
the ravines. In nature and texture they are quite similar to the true glacier
ice, possessing in all cases planes of stratification which indicate the pressure
of the formerly overlying masses." The principal glacier is on the north
slope of the mountain. Of it Mr. King remarks as follows : '' Receiving
the snows of the entire north slope of the cone, it falls in a great field,
covering the slope of the mountain for a breadth of about three or
four miles, reaching down the caiions between four and five miles, its
lower edge dividing into a number of lesser ice-streams, which occupy the
beds of the caSons. This mass is sufiiciently large to partake of the con-
vexity of the cone, and judging from the depths of the canons upon the south

tlie American Journal of Science, for March, 1871 (Third Series, Vol. I. p. 157), and Mr. Emmons read a
pajier entitled "The Volcanoes of the United States Pacific Coast," before the American Geographical Society at
its meeting of March 13, 1877. This last-named paper is chiefly devoted to an account of the ascent of JFount
Rainier by himself and Mr. A. D. Wilson.

GLACIERS OX MOUNT SHASTA. 29

and southeast slopes of the mountain, the thickness cannot be less than from
1,800 to 2,500 feet. It is crevassed in a series of immense chasms, some of
them 2,000 feet long b}- thirty and even fifty feet wide. In one or two
places the whole surfixce is broken with concentric systems of fissures, and
these are invaded with a set of radial breaks which shatter the ice into a
confusion of immense blocks. The region of the terminal moraines is quite
unlike that of the Alps, a large portion of the glacier itself Ijeing covered by
loads of angular debris. The whole north face of the mountain is one great
body of ice, interrupted by a few sharp lava ridges which project above its
general level. The veins of blue ice, the planes of stratification, were
distinctly observed, but neither mouUm nor regular dirt-bauds are present.
Numerous streams, however, flow^ over the surface of the ice, l)ut they hap-
pen to pour into crevasses which are at present quite wide."

No statement is made of the height above the sea-level to which the ice
descends at its lowest point. Judging from the appearance of the cone as
seen from the nortli, and from the photographs, it may be about 10,000 feet.
The different views, taken by Mr. Watkins, give the impression that a con-
siderably less area of the surfiice of the cone is occupied by ice than is
described by Mr. King as being so covered. The fact that the debris extend
over so much of the glacial surface is evidently to be explained by the almost
stationary character of these glaciers. Hardly any snow or rain falls upon
them during the sununer, and by far the larger portion of that which de-
scends in winter is evaporated without actual melting, owing to the intense
dryness of the climate. That the cliraatological conditions all througli
California are peculiar, is well known, and these peculiarities extend even to
the summit of Shasta, as is well illustrated by the fact that our party found
on the summit pieces of paper on which the names of visitors had been
recorded, in some instances several years before, and which remained per-
fectly unchanged by decay or discoloration. That the masses of ice should
be limited to the northern side of the mountain is something which might be
expected ; for as the prevailing winds in summer came from the south and
southwest, the moisture which they carried away would be most likely to be
condensed in part, at least, in the eddy which would take place just at the
passage from the warm over to the cold side of the descending slope, which
remains during the warmer part of the da}- in shadow.

A careful examination of all the details of structure of these ice-masses,
by some one who has had experience in similar work in the classic glacier

30 GLACIAL AND SURFACE GEOLOGY OF THE PACIFIC COAST.

reo-ions of Europe, is much to be desired. It is quite likely that the Shasta
glaciers are literally the remains of former more extensive glaciation ; and
that if it were possible for them to be entirely removed, they would not
under the present climatological conditions be able to form again. Judging
from what we know of the conditions necessary for the formation of glacier
ice, and from tlie past history of the glaciation of the Sierra, it is not unlikely
that at the bottoms of the deepest and most persistent snow accumulations
on the flanks of that range ntve or even ice may be found at times when,
as in 1870, the occurrence of several especially dry seasons in succession
has caused the snow to shrink to a minimum. In spite of the dryness of
the atmo.sphere, some of the melting snow must sink down into the mass,
and tiiere are also occasional showers to moisten it, so that in the long
run the formation of mve or even of ice itself may take place. In 1866,
which was a year when there was less than the usual amount of snow in the
Sierra, Messrs. King and Gardner, in the course of their explorations for the
Geological Survey, discovered a bed of ice on the east slope of Mount Ritter,
which was thus described in theii- notes : " In a deep cul-de-sac, which opens
southeast on the east slope [of Mount Ritter], lies a bed of ice two hundred
yards wide, and about half a mile long. It has moved down from the upper
end of the gorge from thirty to fifty feet this year, leaving a deep gulf be-
tween the vertical stone wall and the ice." No such masses of ice were
found by the writer or by any of his corps at any time, in the higher por-
tions of the Sierra farther south ; although such have been reported by
others, but not by persons having had any previous experience in the in-
vestigation of glacial phenomena. It is doubtful whether these residual
masses of ice can with propriety be called glaciers ; they have no geological
significance as such at tlie present time, however interesting they may be
as possible relics of a once general glaciation of the highest part of the
range.

The explorations of Messrs. A. Hague and Emmons on Mount Hood and
Mount Rainier revealed the presence of large glaciers on those volcanic cones,
as would be naturally expected from their great height and high northern
latitude as compared with Mount Shasta. Mount Rainier is 3,000 feet higher
than Hood, and almost two degrees farther north, besides being much
larger in mass ; its glacier system is therefore very much more extensive than
that of the last-named cone. The largest described by Mr. Emmons is that
which forms the head of White River, running north into Paget Sound. Of

GLACIEES IX THE ROCKY MOUNTAINS. 31

this glacier the greatest width on the steep slope of the mountain is said to
be four or five miles, and its length scarcely less than ten.

Mount Baker, which is near the boundary line between the United States
and British Columbia (latitude 49"), and which is 10,791 feet in height
according to the measurements of the U. S. Coast Survey, is said to have large
glaciers upon its flanks, as would be expected from its northerly position and
proximity to the sea.* It has never been ascended by any one possessed of
sufficient scientific knowledge to describe with accuracy the character and
conditions of the ice-fields.

Farther north in British Columbia the absence of maps making any ap-
proach to accuracy, and of detailed geological exploi'ations, make it impossible
to give anything more than tlie most general statements in regard to the
present glaciation of the Cordilleras in their extension north of latitude 49°.
No active glaciers have Ijeen noticed on the eastern ranges, or the continua-
tion of the Rocky Mountains proper, until some distance north of the boun-
dary has been reached.

According to Dr. Hector, the geologist attached to the Palliser Expedition
(1857-60), the mean altitude of the Rocky Mountains between latitudes 49°
and 53' is about 12,000 feet above the sea ; but there is a singular absence
of marked peaks. The chain, according to the same authority, culminates
in latitude 52', where the mountains are very massive, and traversed by pro-
found valleys, the highest offsets from which are occupied by glaciers. Con-
sidering the great elevation and high northern latitude of this portion of the
rano-e, it seems remarkable that so few glaciers should exist there. Mr.
Selwyn, chief of the Canada Geological Survey, in his exploration of 1875,
at the head of Peace River, still farther north, in latitude 56", observed only
patches of snow, sometimes of several acres in extent, but no glaciers or
permanent snow peaks. The altitude of the point ascended by Mr. Selwyn,
and from which, as he remarks, a perfect sea of Alpine peaks and ridges was
visible, was only about 6,200 feet, a falling off in elevation of the chain in
this direction which more than compensates for the increased latitude.

In the Coast Ranges of British Columbia, on the other hand, as might be
expected from their position with reference to the direction of the prevailing

* Professor Davidson, in giving the elevation of Mount Baker as determined li\' the Coast Survey, adds that
the height of the snow-line on the west side of the mountain was found to be 5,301 feet, which he says "is 2,1.10
feet higher than tlie elevation reported hy Alexander Agassiz, which has generally been distrusted." From what
has been previously stated in this chapter in regard to the varying amount of snow on Mo\int Shasta, it will I'eadily
be inferred that any such thing as a fi.^ed snow-line on these volcanic cones does not exist in nature.

o^

2 GLACIAL AND SITEFACE GEOLOGY OF THE PACIFIC COAST.

winds and their proximity to the ocean, glaciers exist in abundance above
the 49tli parallel, and increase in size as we follow the chain towards
the northwest. Below the 51st parallel they only occur high up in the
ran^e ; but, north of that, begin more and more to extend down the valleys,
and finally, in still higher latitudes (about 60°), come nearly or quite to the
sea.

Returning to our own territory, the conditions as to the present distribu-
tion of snow on the Great Basin ranges, and in the higher portions of the
Rocky Mountains, between the parallels of 37" and 43°, may be noticed. In
all this region, as before remarked, there are, so far as known, -no active
glaciers, with the exception of the very small ones recently discovered near
the summits of one or two of the highest points of the Wind River Range.
The condition of this region, as respects snow accumulations, resembles
much that already described as prevailing in the Sierra Nevada, but, on the
whole, with less fluctuation from year to year.

The mountains nearest the Sierra on the east, the Inyo and White Moun-
tain ranges, have their precipitation cut off almost entirely by the more ele-
vated range on the west. The contrast between the amount of rain and snow
fdl on the Invo Range and tlie Sierra Nevada is most striking. The former
runs parallel with the latter, is not very much inferior to it in elevation, and
the crests of the two ranges are hardly more than twenty miles apart, a valley
some 10,000 feet deep intervening. Yet hardly any snow or rain falls on
the Inyo Range, which is quite destitute of any streams on either flank, and
indeed furnishes hardly water enough to keep the explorer from perishing
with thirst. At a time of the year (May, 1872) when the Sierra was deeply
covered with snow for from 2,000 to 3,000 feet below the sunmiit of the
range, the Inyo Mountains opposite liardly showed the smallest trace of it.

Snow remains in patches on the highest points of the most elevated ranges
of the Great Basin, especially the East Humboldt, through the whole year ;
but the amount still left at the close of the drier seasons mast sometimes be
exceedingly small. There are no statistics of the precipitation on these
ranges, )jut there can be no question that it is small, as compared with that
on the Sierra Nevada. As we approach the eastern edge of the Cordilleras,
the regimen of the climate changes somewhat, the rain and snow fall being
no longer limited essentially to the winter season, but extending over the
whole year. Still, in spite of its more equal distribution, the quantity does
not appear to be as large as it is on the Sierra. The writer, with a small

FORMER GLACIATION OF THE SIERRA NEVADA. 33

party, spent the summer of 1869 on the highest portion of the Kocky Moun-
tains, near South Park, and on the western side of the head-waters of the
Arkansas River. During the months of July and August of that year there
were never as many as three consecutive days without rain, and only rarely
as many as two. The rain-fall was quite tropical in character, beginning
about noon, and usually lasting until evening, with occasional violent showers.
In some instances snow fell on the summits of the highest peaks ; but as
a general rule the precipitation did not seem to extend up as high as
that. Thunder and lightning, sometimes very severe, almost invariably
accompanied these rain-falls. In spite of the great number of rainy days,
however, the ground was never more than superficially wet, evapox'ation tak-
ing place with the greatest rapidity, and the whole aspect of the Arkansas
Valley was that of a dry country.

Nowhere on the higher portions of the ranges adjacent to South Park was
anything seen approaching a glacier in character. There were patches of
snow, sometimes of many acres in extent, in sheltered nooks, and in depres-
sions on the northern slopes of the higher peaks. The ainount of snow
remaining through the season did not appear to differ much from the average
quantity left on portions of the Sierra Nevada of corresponding elevation,
and in the same latitude.

Having thus given a general view of the present condition of the Cordil-
leras with regard to the occurrence of snow and ice, we shall now be pre-
pared to discuss the phenomena of former glaciation in the same region.
From what has been said in the preceding pages, it will be evident that, at
the present time, there are no glaciers within the limits of the United States
possessing any considerable significance as geological agents. It is only at
some distance north of our territory and along the Pacific Coast that what
may be properly called a system of glaciers occurs, and which, although up
to this time only very imperfectly explored, is undoubtedly attended by the
usual interesting accompaniments of the formation of moraines and other
glacial phenomena on a large scale. But, as already suggested, there has
been in former times a very extensive development of glaciers, not only in
the Sierra Nevada, Init in the Rocky Mountains also, while indications of their
former presence are not entirely wanting in the ranges of the Great Basin
itself For convenience of description we may begin with the most southern
portion of the Sierra Nevada at which traces of former glaciation have been
observed, and, following the range northward, give such particulars as have

34 GLACIAL AND SURFACE GEOLOGY OF THE PACIFIC COAST.

been obtained in this connection during the various explorations and recon-
naissances of the Geological Survey in that region.

At the time of the beginning of the California Survey nothing was known
in regard to glacial phenomena in the Far West. It was generally assumed
that the ice-capping of the northern hemisphere was something which ex-
tended all around the pole, and it was presumed that what was true for New
England in respect to ice-action would be found to hold also in similar lati-
tudes in the western regions on to the Pacific.

It was with no small interest, therefore, that we began to study, in 1860,
the distribution of the surface detritus on the Pacific coast with reference to
the question of ice-action. Our first year's work was entirelj' or chiefly in the
Coast Eanges, and it was clearly established by our examinations, which
during that year extended from near the southern border of California to a
hundred miles north of the Bay of San Francisco, that here Avas no question
of either glacial or northern drift. All the loose materials on tlie surllice
showed themselves to have been distributed by causes similar to those now
in action. Detrital materials were always found to have been carried by
water down the slopes of the mountain ranges. The source of the debris at
the mouth of any canon was always to be found up the canon, and not at any
point to the north or in any other general direction. There was no striation,
or other marking of the rock surfaces, such as could only be attributed to
the sliding over them of icy masses. The next year, however, took us into
the Sierra Nevada, and here we did not fliil to discover abundant proof of
the former existence of glaciei's on a large scale. The exploration of
1862, 1863, and 1864 showed us that large glaciers had once covered a con-
siderable portion of the Sierra, but only the higher portion ; that in certain
favorable positions, where there was a large gathering-ground tor the ice, —
a cirque of vast dimensions, as at the head of the Tuolumne River, — these
glaciers had tbrmerly descended to a level of between 3,000 and 4,000 feet
above the sea. In the Southern High Sierra, between the parallels of 36^
and 37^ 30', the same condition of things was observed in 1864; abundant
proof was obtained of the former existence of glaciers, v/hich had, under
favorable circumstances, descended to a pretty low level, and had left, as
proof of their former presence, magnificent moraines, — medial, lateral, and
terminal. The rapid rise of the Sierra as we proceed southwards from the
head of the Tuolumne, fully compensates for the decreased latitude, so that
the glaciers were as fully developed between the parallels of 36^ 30' and

FOKMER GLACIATIOX OF THE SIERRA XEVADA. 35

37^ 30', that is about the head of the San Joaquin and King's rivers, as in
the upper valleys of the Tuolumne. South of 36° the chain falls oft' at once,
and beyond that point to the south no trace of former glacial action has
^been discovered by any member of the California Survey.

Going north, on the other hand, froui the Tuolumne, the Sierra Nevada
diminishes rapidly in elevation, the passes sinking from 10,000 to 7,000 feet,
and the crest height being but little greater than the pass height. This
decreased elevation more than counterbalances the gain in latitude, so that
there are no more such jiroofs of long glaciers as that of the Tuolumne,
which was between forty and fifty miles in length, to be seen. The gla-
ciers about the head of the forks of the American River were large, it is
true, but not to be compared with those on the Tuolumne and the San
Joaquin. North of the head of the American, it would appear, from all our
observations, that the ancient glaciers were but small, and we saw but foint
traces of their former existence around Lassen's Peak, or in the region be-
3^ond that cone of nearly 11,000 feet in height, along the volcanic plateau
towards the foot of Mount Shasta.

The region around Mount Shasta was only very hastily examined by the
Geological Survey, and no striking indications of former glaciation wei'e
observed around that great cone by any member of the corps at that time.
Later, Mr. King, as already mentioned, made a detailed exploration of the
mountain, and discovered abundant evidence of a previously greater ex-
tension of the glaciers now existing on its northern slope.

The country north of Mount Shasta was examined al different times, both
by the writer and Mr. Ga-bb, as far north as Vancouver Island and New
Westminster on the Fraser River. What was observed in the course of those
explorations Avill be mentioned further on in this chapter.

Returning now to the Sierra Nevada, for the purpose of giving the neces-
sary^ details in regard to the occurrence of the ancient glaciers of that range,
it will be desirable to fix as nearly as possible the most southerly point at
which unmistakable signs of former glaciation have been observed.

Nothing has been seen, so far as known, of any glacial markings in the
high peaks and ranges of the southern part of the State of California.
Neither in the San Jacinto, San Bernardino, or San Gabriel ranges have
any such indications been observed. These ranges are from 8,000 to 11,000
feet in altitude, and cover an extensive area; but the latitude is too south-
erly. It is true that there are curiously deceptive appearances which are of

36 GLACIAL AND SURFACE GEOLOGY OF THE PACIFIC COAST.

frequent occurrence, and which may be mistaken for glacial phenomena by
inexperienced observers. The peculiar weathering of the granite outcrops
in the Sierra has been repeatedly mentioned in the Geology of California,
and need here only be recalled to mind as the cause of many misconcep-
tions. Some ridges, as, for instance, one on the north side of the Temescal
Range,* are covered with rounded masses of rock, which at a little distance,
and without close examination, seem to be unquestionably drift boulders.
They are, in point of fact, the remains of the disaggregation by weathering
of the concentrically laminated granite, as is easily recognized, when it is
observed that the rock may be found in all stages of passage from the ahnost
solid ledge, faintly marked with concentric bands of color and fine lines
or cracks, up to the entirely detached and boulder-like masses which rest
on the surface, as if brought from a distance and deposited there by ice or
water. Sometimes, however, the granite, instead of assuming regularly
rounded forms, takes on the most fantastic shapes. A locality of this kind
may be seen near Lone Pine, in the valley of Owen's Lake, along the west
side of the so-called Virginia Hills.

Another source of error, especially apt to be met with in the ranges of
mountains of the southern part of California, is found in tlie way in which
detrital materials have often been carried down the canons, entirely beyond
the edge of the mountains, and spread out on the adjacent plains. This
kind of occurrence has already been described in the gravel volume in
speaking of the great " washes " at the base of the high ranges. It need
only here be noticed that such washes always spread out fan-shaped from the
mouth of the canon from which they issue, while true moraines as inva-
riably lie in parallel lines. The former also always present in a cross section
parallel with the range a nearly uniformly rounded surface, the highest
portion of which is directly opposite the mouth of the ravine ; moraines, on
the contrary, exhibit evidence of having been piled up on each side of an
advancing mass of ice, in that they form two very distinct lines of accumu-
lated material, with a deep depression between them and opposite the centre
of the caiion.

As already mentioned, the Sierra falls off" very rapidly in elevation, from a
jioint about opposite the lower end of Owen's Lake. The range here con-
sists of three principal parallel branches, having the continuation of Owen's
Valley, south of the lake of that name, on the east, and Tulare Valley on the

* See Geology of California, Vol. I. p. 179.

FORMER GLACIATION OF THE SOUTHERN HIGH SIERRA. 37

west. The two interior valleys formed by the three i-anges are very deep
caitons with precipitous sides, and are drained by the branches of Kern
River, of which the more westei'ly one, not far from seventy miles in length,
heads to the north of Owen's Lake, on the south flanks of the Moiuit Brewer
Group. The regular line of travel for wheeled vehicles across the Sierra,
connecting the Tulare Valley with Owen's Valley, crosses the range about
fifty miles south of the southern end of Owen's Lake. This pass is a little
over 5,300 feet in elevation, and the adjacent mountains are about a thou-
sand feet higher than this. There is no wagon-road across the Sierra be-
tween the Walker's Pass and the Sonora Pass roads, a distance of somewhat
over 200 miles measured in a direct line along the crest of the range. There
are three foot-trails between the two wagon-roads mentioned, one leading
up the Tuolumne Valley to Lake Mono, and two others crossing near Owens
Lake. The most northerly of these two leads from Visalia in a northeasterly
direction, crossing the Sierra by Mount Brewer and Kearsarge Mountain,
and descending into Owen's Valley opposite the town of Lidependence ; the
other crosses the summit of the eastern ridge of the Sierra at a point nearly
opposite the centre of Owen's Lake, descending to Lone Pine. The two
trails are about thirty miles apart; the northern one, the highest point of
which is not flir from 12,000 feet above the sea-level, is called the Kearsarge ;
the other, which is known as the Hockett (or Hackett) trail, is about 11,000
feet in elevation.

The descent of the Main or western branch of tlie Kern is exceedingly
rapid, it being not less than 10,000 feet between its head and Kernville,
the point at which the Walker's Pass road meets that river, here 2,490 feet
above the sea-level. Of course it would not be expected that the glacier
which once occupied the head of the Kern Avould have descended as low as
this ; and, in point of fact, no traces whatever of any former glaciation were
observed, either by the writer or by any of his corps, at any point on the
Walker's Pass route. All of that portion of the Sierra which lies between
the last-named road and the Hockett trail was mapped by Mr. R. D'Heureuse,
of the State Geological Survey. His notes make no mention of any glaci.il
markings in this region, although it is not probable that his attention was
particularly called to this matter. Mr. Goodyear, however, in 1872, made a
special visit to the Mount Whitney region, crossing the mountains on the
Hockett trail. In his report of this journey,* he says : '' Another point of

* See Proceedings of the Califoruia Academy of Sciences, Vol. V. p. 182.

38 GLACIAL AND SURFACE GEOLOGY OF THE PACIFIC COAST.

some interest is, that though I hunted for them, I found no glacial scratches,
nor any other evidence of the former existence of glaciers anywhere in this
portion of the mountains ; not even on the peak which has been mistaken
for Mount Whitney, and which is over 14,000 feet high ; nor on the top
and sides of another peak which I climbed in the western summit, four or five
miles northwest of Soda Springs, and which cannot be much less than 12,000
feet high ; nor in the caiion of Kern River which I followed, for four or five
miles, — nor anywhere I went did I find any traces of glaciers. This is cer-
tainly somewhat remarkable, when we consider the fact that the mountains
only twenty miles to the north are, according to all accounts, full of glacial
mnrkinu;s. It is true that much of the granite in the region where I trav-
elled is comparatively soft ; but this is by no means the case with all of it,
and much of it is as hard, and as well adapted to jire.serve such markings, as
any in the Sierra."

It appears, therefore, while the very upper portion of the main branch of
Kern River was undoubtedly occupied in former times by ice, the glacier
extended only a short distance to the south ; and that, although originating
in the ver}- highest part of the range, it was far inferior in importance to
some of (he masses of ice occupying depressions in the range farther north.
The reason of this small development of the Kern River glacier is undoubtedly
chiefiy to be found in the fact, that the most westerly of the three parallel
ridges into which the Sierra is here divided almost entirely cuts off the px-e-
cipitation from the other two. On the west side of the main Kern is the
range of the Kaweah Peaks, which is but little inferior in altitude to the
main water-shed, or the portion of the range which divides the waters flowing
into Owen's Valley from those finding their way to the Kern River. These
two nearly parallel elevated ridges are about fifteen miles apart. We have
here, therefore, another excellent illustration of what has already been stated
to exist, in reference to the relations of the crest of the Sierra Nevada in
this region to the Inyo Mountain Range on the east ; from which latter the
precipitation is almost entirely cut off by the superior elevation of the closely
adjacent line of sunmiits on the west. Still another reason exists why no
long glacier found its way down the main branch of the Kern. The topo-
graphical features of the Sierra in the region lying between Owen's Lake and
the Kaweah River are not favorable to the development of a large glacial
system. The Kern runs in a narrow and extremely precipitous valley, whicli
does not open out at its head, so as to form a large gathering-ground for the

FORMEi; GLACIATION OF THE SOUTHERN HIGH SIEHEA. 39

snow and ice. The direction, during all the upper piirt of its course, is
parallel with the trend of the Sierra, and an inspection of the map will show
at once how limited its area of drainage in the higher part of the range is,
as compared with the other principal rivers farther north.

Three rivers of the Sierra Nevada presented in their upper basins all the
conditions necessary for the formation of large mers dc glace, and they were
thus occupied at no very distant period : these were the King's, the San
Joaquin, and the Tuolumne. Of these grand glacial masses probably that
of King's River was the largest, because the area of drainage of this river
is greater than that of either of the other rivers named, while the average
height of the chain in this portion of its extension is greatest. The most
elevated region drained bv the Kin<>;'s is that included between Mount
Brewer, Mount Tyndall, and Kearsarge Mountain, there being here a trian-
gular area, the lowest part of which has an altitude of over 10,000 feet above
the sea-level. Tlie North Fork of the Kinsr's does not head in the nuiin
range of the Sierra, but to the west of the Mount Goddard Group, being
lapped around by the South Fork of the San Joaquin. The length, in a
direction parallel to the axis of the Sierra, of the area diaincd by branches
of King's River, is about fifty miles ; but they only head up as high as the
main divide for a distance of about thirty miles. The North Foi-k joins the
main stream about six miles below the junction of the Middle and South
Forks, and this is about thirt}' miles in a straight line from the crest of the
Sierra. The valley in the neighbofhood of the junction of the three branches
is from 6,000 to 7,000 feet in altitude, and was formerly occupied )>y the
united ice-streams comins; in from above. Allowino; that one third of the
surface of the basin above this point was covered by the King's River system
of glaciers, the connected ice-mass must have had an area of somewhat over
300 square miles. All through this region, the lower portions of the valleys
are smoothed, scratched, and polished, and lateral and medial moraines occur
on the grandest scale ; but nowhere were any markings observed at a lower
altitude than 4,000 feet above the sea-level. Professor Brewer, in his notes
of his examination of this re<^'-ion in 1864, says : " The entire absence of
observed glacial traces at lower levels makes it almost certain to me that the
glaciers did not descend to below 3,000 feet, and indeed no traces have been
seen below 4,000 feet."

The moraines in the upper portion of the King's River basin are among
the largest and most perfect Avhich liave been observed anywhere in the

40 GLACIAL AND SUEFACE GEOLOGY OF THE PACIFIC COAST.

Sierra. The main glacier came down from the vicinity of Kearsarge Moun-
tain along the route of the present trail. About six miles from the summit,
here over 12,000 feet high, it was joined by a side-glacier coming in from
Mount Brewer on the south. Between these two ice-masses a moraine was
formed, of Avhich the present appearance is that of a vast embankment of
loose boulders and angular fragments of rock, piled up with the steepest
slope on which such materials will lie without sliding, the upper edge of the
western side being elevated from 1,400 to 1,500 feet above the bottom of
the valley. On the eastern side, or that nearest to Mount Brewer, is a de-
pression having a depth of from 400 to 500 feet. On the opposite or west-
ern side of the valley is the corresponding lateral moraine, at a distance of
about a mile and a half, having nearly the same altitude as the other one,
but being considerably smaller. The tops of these moraines, especially
of the eastern one, are quite smooth, and are covered with boulders, and
they have a gentle inclination up the valley, looking in the distance as
regular as railroad embankments.* To ascend or descend the sides of these
moraines with animals was a very difficult task ; to travel along on their
crest, comparatively easy. The former tliickness of the glacier at this point,
as estimated by Professor Brewer, must have been at least 1,.300 or 1,400
feet; a mile farther up the valley he estimated it at not less than 1,800 feet.
The valley between the two moraines is pretty free from detritus, and beauti-
fully scored and polished.

On the eastern slope of the main range of the Sierra, opposite the head
of Kern and King's i-ivers, glaciers undoubtedly once existed ; but they did
not descend into Owen's Valley, or even approach it within considerable dis-
tance. The Hanks of the range between Owen's Lake and the Fish Springs
volcanic group are covered up to a jjerpendicular height of over 2,000 feet
with the " wash " previously described, and commonly called the sage-brush
slope. There are no data in the writer's possession from which it can be
clearly made out how much the glaciers, at the time of their greatest exten-
sion, lacked of reaching this belt of detritus. Explorations made in 1872
along the flanks of the range rendered it evident that the ice could not here
have descended as low as a line 7,000 feet above the sea-level ; but there
was too much snow on the mountains at that time, the month being May, to
obtain any satisfoctory evidence on this point.

The valleys occupied Ijy the various branches of the Upper San Joaquin

See Geology of Califoniia, Vol. I. p. 379, for a section across these moraines.

foi;mee glaciatiox of the tuolomne a^alley. 41

present also the usual phenomena of former glacial action on a magnificent
scale. The main tributary of this river in the High Sierra is the so-called
South Fork, which heads in two streams, one coming down from the north
side of Mount Goddard, and the other from the north end of the Palisades.
The principal stream, receiving many tributaries, runs about fifty miles in a
direction parallel with the axis of the chain, or northwest, and then unites
with the North Fork, a much smaller branch coming down from the portion
of the ridge between lied Slate Peak and Mount Lyell. The total length of
the portion of the Sierra drained on its western slope b}' the San Joaquin is
between fifty-five and sixty miles This area has been but very imperfectly
explored by the Geological Survey ; but abundant evidences were obtained
of the former existence of glacial masses in this region, on a scale perhaps
even grander- than in the King's River area. In the valley of the San
Joaquin, on the South Fork, Professor Brewer inferred, from the position of
the old moraines, that the former glacier must have been at least 1,500 feet
deep, and eight or nine miles wide in its widest places. The length of
the whole South Fork glacier, measuring to the termination of the ice in the
Main Valley, must have been over fiftj^ miles. Neither in the case of the
King's nor the San Joaquin River glacier has the precise point of the valley
reached by the glacial mass at the time of its greatest extension ever been
ascertained.

The formerly glaciated portion of the Sierra Nevada, which has been most
carefully explored by the Geological Survey, is that at the head of the Tuolumne
River. This region, from its importance as being in the most accessible part
of the range, near the Yosemite Valley, and consequently much more visited
by pleasure-travellers than the Southern High Sierra, was mapped on a
larger scale than the rest of the range,* and sufficiently studied to make it
possible to lay down the position and extent of the ancient glacial mass with
considerable approach to accuracy.

The length of that part of the Sierra ^\■hic•h is drained by the Tuolumne,
measured parallel with the axis, is a little less than forty miles. The prin-.
cipal gathering-ground of the glacier was in the elevated plateau-like region
embraced between Cathedral Peak, Mount Conness, Mount Dana, and Mount
Lyell, forming an irregularly shaped area of some sixteen miles in length
and from six to ten in breadth. The lowest part of this area is a little less

* This map, comiinsint; aljnut 2,300 squarB miles, and on a scale of two miles to an inch, accompanies the 4to
and Svo editions ol'the Yosemite Gniile-Book. A reduced iihotolithographir; copy, on a scale of three miles to an
inch, is also given in the 16mo edition of the same work.

42 GLACIAL AND SUEFACE GEOLOGY OF THE PACIFIC COAST.

than 9,000 feet in elevation, and the ice in this portion of the valley must
have formerly been over a thousand feet in thickness. Into this basin came
down branches of the ice-flow from the Mount Conness Ran2;e on the north,
from the pass just north of Mount Dana, formerly known as McLane's Pass,
and from Mono Pass on the east, and from tlie mass of Mounts Maclure and
Lyell on the south, this latter being the most extensive of all. The lateral
and medial moraines of all these difterent flows are as plainly visible on the
surface as if the ice had but just melted away and left them. They are
particularly well marked where the glacier coming down from Mono Pass
united with that descending from McLane's Pass.

At Soda Springs the valley of the Tuoknnne begins to narrow gradually,
and two miles below commences the remarkable gorge which continues for
twenty miles as a grand caiion, with extremely precipitous walls from a
thousand to fifteen hundred feet high, between which there is hardly any-
where much more than room enough for the river to run over its rocky bot-
tom. The walls of this cauon, however, although very steep, are nowhere
perpendicular as in the Yosemite ; neither are there any of those sudden
perpendicular drops of its floor, such as we have where the Merced falls over
the squarely-cut granite edges in plunges of 600 and 400 feet at the Nevada
and Vernal Falls. The whole of this canon of the Tuolumne has been occu-
pied by a glacier, as both the bottom and the sides show abundant evi-
dences of glacial striation and polish. Detrital accumidations, however, are
extremely rare in it. The facts observed prove very clearly that the form
of the canon has been in no respect due to ice-action. Projecting edges have
been rounded and smoothed. But the ice-mass followed the channel pre-
viously prepared for it : it did not do the work of excavation itself A brief
study of the position of the glacial markings is sufficient to establish the fact
that the canon could never have been excavated by the glacial mass which
once filled it.

If it be asked lioiv this is shown, the answer can be very easily given.
If the canon had been excavated by the movement of the ice with which it
is admitted that it was once entirely filled, it would of necessity show that
this was the case by presenting exclusively, everywhere in its course, the
characteristic features due to ice-work. To use a homely illustration : if one
were to work out a trough in a plank with sand-paper alone, the resulting
cavity could not have angular recesses and projecting edges in it, for sand-
paper is a tool or material which cannot originate forms of that kind. So, in

THE FORMER TUOLUMNE GLACIER. 43

the Tuolumne Canon, the larger portion of the surface is rough and angular,
showing deep recesses, and squarely-cut buttresses, which sometimes pro-
ject out directh' in the path of the ice, as if on purpose to brave its erosive
power. Only in places is even the bottom entirely smoothed over ; while
the walls have onlv those projecting edges and surfaces rounded and pol-
ished which faced the direction from which the ice was moving, or projected
out into the valley so as to be easily reached by it. Hence it seems rea-
sonable to infer that ice has done but a very small part of the work of
excavation, which was in reality performed by other vastly more potent
agencies.

Tlie Tuolumne River in the cailon has a rapid fall, averaging about 200 feet
to the mile, the stream itself varying greatly in size with the varying conditions
of the years and the seasons. A considerable part of its descent is made by
a series of beautiful cascades over shelving rocks, the scenery being ex-
tremely gran I and attractive, although by no means to be compared with
that of the Yosemite Valley.*

North of the Tuolumne Canon, and west of the Mount Conness Range, is
an elevated plateau-like area of almost bare granite, which rises gradually
towards the northeast, and culminates in the range dividing the head-waters of
the Tuolunme from those of Walker's River, and of which the strand and iao-ired
mass of Tower Peak is the dominating point. This plateau is intersected by
several parallel streams which run in a southwest direction from the Tower
Peak Range, and enter the Tuolumne Canon over its edge in a series of falls
and cascades, which are described, by those who have seen them at a time
when greatly swollen by the melting of the winter's snow, as being very
grand. All this granite slope is beautifully polished and striated, and the
mass of ice which once covered it must have chiefly found its way into the
Tuolumne Caiion, and added to the volume of that great mass of ice. It
needs but a glance at the map to see how exceptionally favorable the condi-
tions were in this part of the Sierra for the formation of a large glacier ; and
it is thus easy to account for the great length of this one, as compared with
those farther to the north in the rano-e, where there is no recurrence of simi-
lar topographical features on anything like the scale exhibited at the head
of the Tuolumne.

Below the goi-ge just noticed, the canon opens out and presents a remark-
able counterpart of the Yosemite, known by the name of the Hetch-Hetchy

* For some details in regard to the seenery of tbe Tuolumne Cauon, the Yosemite Guide-Book, edition of
1874, may be consulted.

44 GLACIAL AND SURFACE GEOLOGY OF THE PACIFIC COAST.

Valley. This has been sufficiently described in the Yosemite Guide-Book ;
but a few words must here be added in regard to the interesting glacial
features of this curious locality. The Hetch-IIetchy is about fifteen miles
northwest of the Yosemite, and is similarly situated with reference to the
crest of the Sierra, from which its upper end is about twenty miles dis-
tant. Both these valleys have been lakes in former times, and the Hetch-
Hetchy still becomes one not unfrequently, the gorge below it being too
narrow to carry off all the water at the time of the melting of the snow in
the spring. The bottom of the valley is about 3,650 feet above the sea, or
about 300 feet lower than the Yosemite. Unlike the latter, it is separated
into two pretty distinct divisions by a precipitous spur of granite, which pro-
jects out from the southern side, and the sides of this mass, as well as the
walls of the valley, are beautifidly scored and polished up to a height of at
least 800 feet above the level of the river. The walls of the Hetch-Hetchy
are nearly 2,000 feet iu height, and very precipitous, with but a small
amount of talus at the bottom, as is the case in the Yosemite. No doubt
the exact thickness of the glacier by which it was formerly filled could be
accurately determined by careful examination. From the observations of
Mr. Iloffinann, by whom this interesting locality was first made known to the
public, it appears that below the Hetch-Hetchy the trail runs for some dis-
tance along- the top of a moraine, at an elevation of 1,200 feet above the
level of the i-iver. The valley has not been explored below the Hetch-
Hetchy for the purpose of ascertaining the exact point to which the Tuo-
lumne glacier descended at the time of the greatest extension of the ice ;
but it must have reached nearly or quite down to the junction of the South
Fork. In that case the total leno-th of the mass of ice would have been
about fifty miles ; it was certainly over forty. The width must have been
more than four miles at some points in its course, and it may in places have
exceeded six.

Between the San Joaquin and the Tuolumne rivers is the Merced, the
glaciation of whose v.alley is next to be discussed. This stream is more in-
terQsting than any other in the High Siei'ra, because it is the only one much
seen in the upper part of its course by travellers and tourists, since it runs
through the Yosemite Valley, the one feature of Californian scenery which
attracts universal attention. It is the more desirable that the glaciation of
the Merced Valley, including the Yosemite, should be somewhat minutely
described, because there seems to be a strong feeling, in California at least.

FORMER GLACIATIOX OF THE MERCED VALLEY. 45

that the remarkable scenic features of that locality are, in some way, the
result of glacial action. It seems surprising that a theory so utterly averse
to the facts should have ever gained currency, and it is almost humiliating
to be obliged to enter into an argument to prove that the Yosemite Valley
was not dug out of the solid granite by ice.

The head of the Merced hardly reaches the summit of the Sierra. It is
lapped around by branches of the San Joaquin on the south, and of the Tuo-
lumne on the north. All three of these streams head in the great central
mass of which Mount Maclure and Mount Lyell are the dominating peaks.
From this nodal point, however, great spurs extend to the southwest and
northwest, enclosing triangular areas between themselves and the main
divide, and which are drained by the tributaries of the San Joaquin and
Tuolumne, thus limiting the extent of the real summit range included in
the basin of the Merced to a distance of hardly more than a couple of miles
on the west side of the Mount Lyell Group.

The real sources of the Merced are the various streams coming down from
the southwest side of the spur of the Sierra which leads from Mount Mac-
lure to Cathedral Peak, and from the northeast flanks of the Mount Clark
Range. The latter is a lofty mass of granitic rocks, which runs parallel with
the main crest of the Sierra, at about eight miles' distance, and is connected
with it by a transverse ridge. The plateau-like space thus enclo.sed is about
eight miles by ten in dimensions, wdth sides rapidly descending towards the
centre, where in a deep cailon runs the Merced. The lower portion of this
quadrangular area was formerly occupied by a glacier whose arms extended
up the depressions between the different spurs coming down from the main
ridges enclosing it on three sides.

The glacier which was thus formed at the head of the Merced was probably
not by any means as thick, and it certainly was not so extensive, as that
which occupied the Upper Tuolumne Valley on the other side of the Cathe-
dral Peak Range. The reasons of these inferior dimensions are easily found
in the smaller size and diminished altitude of the iratherino;-o;round at the
head of the Merced. This latter is nearly tAvo thousand feet lower, on the
average, than the broad valley to the north, which formed the main reservoir
into which descended the numei-ous tributaries which combined to form the
main glacier of the Tuolumne. The area at the head of the Merced, besides
having the disadvantage of inferior altitude, is so situated that it could
receive only one important tributary, namely, that coming down on the east

46 GLACIAL AND SUEFACE GEOLOGY OF THE PACIFIC COAST.

side of Cloud's Rest, and which was, in fact, simply an ovei'flow from the
vastly greater mass of the Tuolumne glacier.

The Little Yosemite is a flat valley or mountain meadow, about four miles
long, and from half a mile to a mile wide. It is, essentially, a continuation
of the Great Ycsemite on a somewhat diminished scale, and is separated from
it by only a couple of miles of distance, in the course of which the Merced
River descends 2,000 feet, half of which is in two pei'pendicular falls, the Ne-
vada and the Merced. The Avails of the Little Yosemite are irregular in form,
and consist of almost bai'e granitic masses, showing everywhere a most per-
fectly developed concentric structure. Down this valley the Merced glacier
passed, and just above the Nevada Fall it was joined by the branch from
the Tuolumne glacier, as already mentioned. The moraines left by this last-
named branch, along the back or eastern side of Cloud's Rest, are very con-
spicuous objects to the traveller following the trail from the Yosemite over
to Soda Springs in the Tuolumne Valley, and they are indeed much larger
than any of the moraines noticed as belonging to the Merced glacier projier.
Just to the southeast of Cloud's Rest the moraine sunnuit was found to be
765 feet above the Merced River; but it does not come within 1,500 feet
perpendicular of the crest of the ridge of which the Half Dome and Cloud's
Rest are the two culminating points. The last traces which could be found
of the Merced glacier were at a point a little above the Nevada Fall. The
most careful search failed to reveal any signs of glaciation in the canon
below the fall. Nor were there any scratches or polished surfaces found on
the high points immediately south of the Little Yosemite, especially in the
vicinity of Mount Starr King, a curious, isolated, inaccessible cone of granite,
rising among a group of similar elevations.

Another arm, or overflow, of the Tuolumne glacier came down the caiion
of the Tenaya Fork of the Merced, on the west side of Cloud's Rest; and it
was in all probability joined by an independent ice-flow of considerable di-
mensions coming in from the east side of the Mount Hoffmann Range. The
highest point of this group of summits, which lies about midway between the
Yosemite and the grandest part of the Tuolumne Caiion, is nearly 11,000 feet
in elevation ; the pass leading from Tenaya Lake, at the head of the Tenaja
Valley, over to the Tuolumne Valley, is about 9,000 feet above the sea-level.
All through this region the rocks are beautifully polished and striated, and
these evidences of former glacial action are especially conspicuous about
Tenaya Lake, at the head of which is an isolated conical knob, which i-ises

FORMER GLACIATIOX ABOUT THE YOSEMITE. 47

to a height of about 800 feet above the level of the lake ; its sides, nearly or
quite to the summit, ofler abundant traces of glaciation. The contrast be-
tween the sharp pinnacles of which the highest points of the Cathedral
Peak Range are made up and the rounded and polished surfaces in the
valley below is most striking.

The descent of the Tenaya Fork to the Yosemite is very rapid ; the dis-
tance from the lake to the valley being about ten miles, and the difference
of elevation fully 4,000 feet. Thick as were the ice-masses at the head of
the Tenaya Caiion, the most careful search foiled to reveal any pi-oof that
they had ever descended so far as to reach the Yosemite itself. The lower
part of the caiion is jiretty much choked up by huge blocks of granite which
have tumbled from the adjacent precipitous walls ; but neither the rock in
place nor the loose masses exhibited any signs of striation.

It woiUd appear, therefore, that neither the Mei'ced glacier nor the over-
flow of the Tuolumne ever descended so far as the Yosemite ; consequently
the ice never entered this valley, as it could only have been supplied to it
fiom those sources.* The walls of the Yosemite on each side were carefully
examined by the writer without his having been able to find on them any
signs of smoothed, striated, or polished surfaces which could be unhesitatingly
set down as the work of ice. There are, it is true, many places where the
surface of the granite is very even and smooth ; but a close inspection will
always be sufficient to establish the fact that this is a structural peculiarity
of tlie rock itself, and not of glacial origin. All throughout the Sierra, as
has been already mentioned, but especially in the vicinity of the Yosemite,
the granitic masses ha\'e a most marked tendency to separate in concentric
shells. This structure, which seems to pervade tlie rock to a great depth, im-
presses itself most strongly on the scenery, the surface seeming to be covered
with a succession of domes and conical Icnobs, some of which, as in the case
of Mount Starr King, rise up so steeply as to be quite inaccessible. As these
shells or plates separate from each other under the influence of varied me-

* The statements made by tlie writer in tlie Geology of California, Vol. I., to the effect that a glacier had once
tilled the Yosemite Valley, is an error, which has long since been corrected in the various editions of the Yosemite
Guide-Book. The mistake was caused by too much dependence being placed on the reports of a.ssistants entirely
inexpeiieiiced in the study of glacial phenomena. Since the Geology of California, Vol. I., was jiublished, the
Yosemite and the adjacent region have more than once been carefully examined by the writer himself.

Mr. J. F. Campbell, author of "Frost .and Fire," a practised observer, says, in his work entitled My Cir-
cular Notes, "A local geologist found marks which indicate the presence of a large glacier in the Y'oseinite
Valley ; I sought carefully, and found no marks of glaciation there."

48 GLACIAL AND SUEFACE GEOLOGY OF THE PACIFIC COAST.

teorological conditions, tliey expose great rounded surfaces, of wliich the
smoothness is well calculated to deceive careless or inexperienced observers.
Similar surfaces may, however, almost invariably be found in the immediate
vicinity of such exposures, where the conditions are such that it is seen at
once that ice cannot have been the agent in bringing about the peculiar
smoothness and curved form of the rock. There are plenty of deeply
recessed portions of the Yosemite Valle}', where at the bottom of a cavity
entirely inaccessible to ice the same smoothness may be observed. Around
these are the overlapping edges of the successive plates, by the removal of
parts of which the cavity has been formed. These will all have sharp edges,
an occurrence entirely impossible if the removal of the wanting portion had
been effected by glacial erosion.

The only thing in the Valley which might with some plausibilit}' be re-
/ferred to the agency of ice is the small moraine-like elevation at the head
^ of the Bridal Veil Meadow, referred to in the Geology of California, Vol. I.
This, as well as the whole Vallej^, the writer has re-examined since that vol-
ume was written, and has become thoroughly convinced that it is not neces-
sarily of glacial origin. A moraine in the Yosemite Valley would without
doubt be composed of similar materials to those which constitute the present
talus at the bottom of the walls of the Valley. These are all made up chiefly
of coarse angular blocks of granite with a little finer granitic detritus mixed
with them, such material, in short, as would be formed by the cracking off
and falling down of portions of the walls of the Valley. The supposed mo-
raine, however, is made up of fine material ahnost entirel}', and it appears
very probable that it was formed at the time when the Valley was a lake,
by the crowding of the ice against the shore, at the time of the winter's
freezing. This mode of building up of walls and moraine-like accumulations
around the shores of lakes is a phenomenon of frequent occurrence. In tlio
case of the Yosemite the formation of such a pile of debris at its lower end
would be materially aided by the violence with which the wind frequently
blows up or down the Valley. This, even now, is occasionally almost sub-
merged at the time of the most rapid melting of the snows on the adjacent
heights, after winters of unconnnonl}' large precipitation. The Hetch-Hetchy,
on the other hand, according to Mr. Hofi^"mann, is transformed into a i-egular
lake at such times.

It being, as the writer after a careful examination believes, a well-estab-
lished fact that the Yosemite was not occupied by ice during the time of the

FORMATION OF THE YOSEMITE VALLEY. 49

former extension of the glaciers over the higher portions of the Sierra, a few
words may be added to wliat has been said, for the purpose of showing that,
even had the Valley been so occupied, there is no reason to believe that its
form would have been essentially modified by any erosive agency of the ice
which passed through it. Bearing in mind what has already been said in
regard to the glaciation of the Tuolumne Canon and the Hetch-Hetchy
Valley, it may be added that the form of the Yosemite is still more unlike
anything that could have been effected by any kind of ero.sive action,
whether of ice or water. Following down the Merced from the Little Yo-
semite, we have in tiie first place two vertical steps of descent, of 600 and
400 feet. Even now, after the river has poured its volume of water over these
precipices for ages, their edges remain wonderfully sharp. These vertical
steps downwards along the line of descent of the supposed glacial mass are
something of an entirely difterent natui'e from any results which either ice
or water is accomplishing at the present day. But the whole Yosemite shows
in all its details a succession of forms which never could have been produced
by any kind of erosion. Such rectangular, squarely cut recesses as that at
the head of the Valley, over which the Vernal and Illilouette falls descend,
could never have been produced by flowing material of any kind. And
all through the Yosemite there are vertical, or nearly vertical, walls of rock
from one to two thousand feet in height, which are turned entirely in the
opposite direction, and, so to speak, hidden away from any possible approach
of an erosive agent. An examination of the large map of the Valley accom-
panying the 8vo and 4to editions of the Guide-Book would suffice to con-
vince any candid inquirer that such faces of rock as those on the west side
of El Capitan differ I'adically from anything exhibited by oi'dinary valleys of
ei'osion. A moving mass of ice could only have acted in the direction of its
own line of motion. Angular forms could never by any possibility be cut
out at right angles to that direction. Most surprising, and contrary to all
the facts, is the attempt which has been made to explain such remarkably
exceptional formations as that of the Half Dome by glacial erosion. The sum-
mit of this stupendous mass rises to a height of more than 2,000 feet above
any point which ice could ever have reached. It has not a glacial scratch
upon its surface at any point. Its smoothly rounded back and dome-shaped
summit are found on examination to be strictly conditioned b}- the internal
structure of the mass itself, which along the edges of its broken front everj'--
where shows the overlapping concentric shells of which it is made up. As

/

50 GLACIAL AND SURFACE GEOLOGY OF THE PACIFIC COAST.

if to remove every possibility of a glacial theory of its origin, it presents in
precisely the direction from which any moving body of ice must have ap-
proached, — namely, towards the head of tlie Tenaya Canon, — a series of
immense projecting plates, the edges of which are sharply cut and do not
exhibit the least indication of rounding by glacial or any other erosive force.

Below the Bridal Veil Meadow, at the lower end of the Yosemite proper,
the whole character of the valley changes; the sides assume the ordinary
V-shape due to erosion by water, and the piles of debris at their base become
conspicuous. All the characteristic Yosemite features, — the vertical walls,
the rectangular projecting cliffs, the 'almost entire absence of talus, — tliese
all disappear as soon as we enter the caiion below.

All along the Sierra Nevada in the vicinity of the head of the Tuolumne
River, there is abundant evidence that the glacial masses covering so exten-
sive a portion of the western flanks of the range also extended far down on
the eastern side. Above the group of volcanoes near Fish Springs in Owen's
Valley, the eastern slope of the Sierra has been but ver}' slightly examined
by the Geological Survey. The deep caiions down which Big Pine, Bishop's,
and Indian creeks descend are, in all probability, glaciated in their upper
portions; but there seem to be no morainic accumulations of great size reach-
ing to a considerable distance below the summit, as is the case farther north.
All along this side, however, from Round Valley north, as for as Big Mead-
ows, twenty miles beyond Mono Lake, the moraines left by the glaciers
formerly descending the eastern slope are extremely conspicuous.* A very
extensive glacier formed on the east side of the liigh group of summits to
which Mount Ritter and Mount Maclure belong. This body of ice pushed its
moraines at least six miles to the north, towards Mono Lake. At the
southern end of this lake is an extensive group of volcanic cones and craters,
which rise to the height of from 9,200 to 9,300 feet above the sea, the
highest being about 2,750 feet above the level of Mono Lake. These cones,
which are chiefly made up of ashes and j^umice, have retained their original
shape in almost entire perfection, shoAving that the amount of precipita-
tion in the form of rain in this region must be very small, as otherwise they
could not foil to have been more or less washed away. Professor Brewer,
who ascended the highest of these old volcanoes, noticed several blocks of
granite near the sunnnit and within its crater mixed with the ashes. This

* The position of the most iiupoitant ol' these moraines will be fouiul laiil down on the soutlieast-quarter sheet
of the Central California Map of the State Geological Survey.

FORMER GLACIATION OF THE EASTERN SLOPE. 51

mio;ht seem, at fii-st sio-ht, as if indicative of the fact that the 2;lacier
came down the northeast slope of Mount Ritter. This would be hardly
possible, however, for the position of the moraines to the south does not
indicate that the glacier ever rose as high as this ; and, indeed, so great a
thickness of the ice, at so low a level as 7,000 feet, oil the eastern slope,
Avould not be in harmony with what has been elsewhere observed in this
region. Besides, it seems impossible that glaciers should have passed over
those cones of easily movable ashes without spoiling their symmetry, which
has certainly not been accomplished. The advocates of the excessive erosive
power of moving ice certainly could not admit that these cones have ever
stood in the path of a glacier. It is not impossible that the granite should
have been thrown up froui below by volcanic forces. Certainly everywhere
in the Sierra lava and ashes have been projected in astonishing quantity
through this rock, and it would not appear that any positive reason can be
given wh}' some portions of the underlying gi\anite should not have come to
the surface with the purely volcanic materials.

As a general rule these morainic accumulations on the eastern slope of the
Sierra are massive and extremely well marked. They extend out a few miles
from the edge of the mountains, and then come at once to a stop, the posi-
tion of their terminal point being as easy as possible to fix.

In the gorge leading down from the Mono Pass, which is 10,765 feet in
elevation, there are abundant evidences of former glaciers, from near the
summit to the very foot of the cailon". The rocks are rounded, polished, and
grooved, and from the bottom of the mountain large piles of detrital ma-
terials extend out into the plain for several miles. According to Mr. King,
the lower portions of these moraines exhibit distinct traces of terraces, indi-
cating that at the time of the accumulation of these piles of detrital materials
Mono Lake stood at a much higher level than it now does. This condition
of things has received abundant confirmation from other facts observed all
through the region east of the crest of the Sierra Nevada. Unfortunately,
barometric observations were not taken along the base of these moraines, so
that the precise altitude of their termini above the sea, or above Mono Lake,
is not known ; the position of the terraces immediately upon the shores of
that lake, however, show it to have been, at one time, at least 600 feet
higher than it now is.

All through the region at the head of the Tuolumne River the perfection
with which the moraines are preserved was, for the party exploring that por-

52 GLACIAL AND SURFACE GEOLOGY OF THE PACIFIC COAST.

tion of the Sierra, a constant theme of remark. Not less striking was the
polish of the rock surfaces, which often, when struck by the sunlight at the
right angle, glittered in the distance like mirrors. In crossing from Tenaya
Lake to Soda Springs the rocks for long stretches were bare, and so smooth
that the mules could with difficulty keep their footing. The fact was re-
peatedly noticed, all through this region, that where a great thickness of ice
had formerly rested on the granite, which is almost the only formation of
this glaciated region, the surface of the rock seems to have undergone a
molecular change, a sort of crust having been formed, as if by the crushing
and compacting together of the crystalline minerals of which the granite is
made up. This crust appears to be more durable than the body of the rock ;
and, in the process of weathering, the exterior sometimes scales off in plates
or flakes, half an inch thick or more, of which one side is as nicely polished
as if the Avork had been done only yesterday. Other portions of the granite
which have not been subjected to this pressure seem to be eroded with com-
parative rapidity, and their surfaces are often quite irregularly worn out in
cavities. Professor Brewer thought that he observed this peculiar change
of the crust of the granite to be strikingly developed in certain portions of
the Mono Pass, where the glacier had been forced to make its way through
narrow gorges, and where, in consequence, the pressure exercised on the
enclosing rocky walls must have been enormous.

The locality farthest north in the Sierx\a where any extensive proofs of
former glaciation have been discovered, -^ so for as known to the writer, —
on the eastern slope of the range, is at a point about ten miles northwest of
Mono Lake. Here, at the head of Walker Piiver, and between Castle Peak
and the Tower Peak Range, is a depression in the Sierra over which crosses
the so-called Virginia Trail, once considerably used as connecting the Upper
Tuolumne and Merced rivers with Aurora and the mining districts of
Nevada.

This trail crosses to the southeast of Castle Peak ; but Green River, which
heads at the summit of the pass, finds its way down the eastern slope on the
northwest side of this mountain, which is nearly 12,000 feet high. In the
canon of this stream a very large glacier once descended almost to the level
of the Big Meadows. The moraines left by it are very large and distinct,
forming two parallel ridges, some 350 feet in height, made up of the usual
angular debris of the range above. It was noticed by the writer, how much
these moraines resembled, both in form and size, the detrital accumulations

FOR^^IER GLACIERS AT THE HEAD OF THE STANISLAUS. 53

of similar origin in the Upper Arkansas Valley. It was also remavked that
here, as in most cases in the Rocky Mountains, the lateral moraines high up
in the range seem to have been almost entirely obliterated, while those low
down, on the nearly level valley, at the base of the mountains, are not only
of immense size, but perfectly preserved in form.

Passing to the north of the Tuolunme River, we find a very considerable
change in the topography of the Sierra, accompanied by a rapid decline in
its altitude. These altered conditions make themselves manifest at once
in the character of the traces of former glaciation which are discoverable.
There are no more such immense ancient glacial systems as those of the
King's and Tuolumne rivers, which rival with or even surpass the largest
ice-fiows at present existing in the Alps. This is as we should exjject, for the
traces of former glaciers are everywhere in the Sierra Nevada found to be
in strict harmony with its present climatic and topographic features. From
the head of the Tuolumne north there is no longer one almost unbroken
western slope to tlie range, Avith an extremely rapid descent on the east into
a deep valley, separating the Sierra Nevada most distinctly from the Great
Basin ranges ; the mass becomes more and more split up into subordinate
parts by spurs making off to the north and inosculating with still more
easterly ranges, so that any line of division between them must be largely
artificial. Finally, when we reach Plumas County we have several nearly
parallel ranges of about equal elevation, enclosing extensive valleys, where,
however, the elevation is not great enough to have given rise to large gla-
ciers, and where the diminished precipitation also makes their former exist-
ence less probable.

Another circumstance renders the conditions of the northern portion of
the Sierra less favorable than they are farther south for the observation
of the traces of former glaciation. The farther we go north the more the
higher portions of the range become covered with volcanic materials, which
are almost entirely wanting about the upper basins of the large rivers of the
High Sierra. These volcanic rocks are not fiivorable either for receiving or
retaining glacial striation or polish.

The next stream of importance, north of the Tuolumne, is the Stanislaus,
and the range of the Sierra at its head is still quite high, the Sonora Pass,
which leads from the head-waters of the Stanislaus to those of the West-
Walker River, being about 10.000 feet above the sea-level. But glacial
markings were not seen on the eastern slope of the pass at a distance from

54 GLACIAL AND SUEFACE GEOLOGY OF THE PACIFIC COAST.

the summit of over two miles. Above that they were abundant, and they
were also seen high up on the elevated ridges south, which rise to an alti-
tude of nearly 12,000 feet above the sea-level. The spurs between the
branches of the Stanislaus, for a considerable distance below the summit,
exhibit indications of the former existence of masses of ice of great thickness.
Professor Brewer's notes give the following particulars in regard to these
occurrences, obtained in his examinations along the Sonora Pass road, in
1863 : "We camped at the lower crossing of the Stanislaus, about eighteen
miles west of the summit, and examhied the hills south. The sides of the
caiion rise abruptly to the height of 2,500 or 3,000 feet. Granite extends
to within perhaps 700 feet of the higiiest point reached, which was of
volcanic, rudely columnar. Higher mountains are on every side, mostly
of o-ranite, capped with lava. On the ridges. lying between the forks of
the Stanislaus, north of us, these were exceedingly grand, rising perhaps
3,500 feet above the river. Their tops were worn into fontastic forms ; one
was not unlike an immense castle crowning the bold mountain. The rock
of the spur or ridge reached was of porphj^ritic lava, rather soft. Perched
near the top were ten or twelve large granite boulders, wliich must have
been deposited by ice, since they could not possibly have been carried
there by water. They were of coarse texture, the feldspar crystals very
large, some angular, others rounded and weathered. One of these, perched
on a very sharp ridge, measured seventeen feet long, fourteen wide, and
twelve high ; the others were smaller. Another lava spur, a fourth of a mile
east, had its top strewn with similar boulders. These must have come from
the east, where at the distance of three or four miles there is gi-anite at
a greater elevation than that of these boulders, and they must have been
brouo"ht by o-laciers that flowed from the hitjher mountains down the canon
of the Stanislaus River. No glacial polishings were observed, but the rock
is not well calculated to preserve them." Nothing indicating the passage
of glaciers was observed farther down the Stanislaus Valley. The road
descended at a considerable height above the river, the bed of which was
examined by the writer, at a point near the Sugar Pine mining district, and
no signs of glaciation found. This, however, was at a level probably consid-
erably below the point to which the former glacier reached at the time of
its greatest extension.

At a still lower level, namely, of about 2,200 feet, between Sonora and
Columbia, several square miles of the surface of the limestone rock have

FOEMEE GLACIATIOX AT THE HEAD OF THE MOKELUJUNE. 55

been cleared of the overlying detritus by those engaged in washing for gold.
Nowhere can a trace of the former existence of glaciers in this reo-ion be
discovered. Indeed, there is not a locality in the. Sierra where any proof
whatever has been obtained that the ice descended, even in the most favor-
able positions, to a point as low as 2,000 feet above the sea-level. And a
large extent of rock-surface has been exposed, all through the auriferous belt,
by the various and extensive mining operations there carried on.

The Mokelumne River heads in a group of high peaks six miles south of
Silver Mountain ; the eastern slope is drained in this part of the range by the
head-waters of the Carson. Numerous branches of the South Fork of the
American River take their rise in the northwestern slopes of the spurs whose
opposite sides drain into the Mokelumne. The Cosumnes River, wliieh runs
into the Sacramento between the Mokelumne and the American, does not
head so far up as the summit range of the Sierra. This stream need not,
therefore, be taken into con.sideration in describing the foi'mer glaciation of
the region. The Mokelumne, also, is of little importance in this connection ;
for, although its sources drain an elevated district, there are no important
affluents coming into it at high altitudes, so that there was no chance for
the formation of a large glacier at its head. The lowest point in this region
at which evidences of the former presence of ice were detected was Silver
Valley, 7,300 feet above the sea-level. This locality is in the Stanislaus
Valley, about twenty-two miles from the Calaveras Big Trees, on the road
to Silver Mountain. At Hermit Valley, on the Mokelumne, at an altitude
of 7.259 feet, distinct marks of o;lacial action were met with, and from this
point they continued to l)e observed in abundance almost up to the very
summit of the pass, the height of which is nearly 9.000 feet above the sea-
level. No extensive moraines were seen ; but it can hardly be doubted that
a sufficient amount of detailed exploration in this region would make it
possible to lay down the ancient limits of the ice with considerable approach
to accuracy. The thickness of the mass must have been great in this region,
just in the vicinity of the sunnnit, for large blocks of granite may be seen
on the crest of a ridge, about 300 feet high, a little south of tlie pass, resting
on the lava in a position such as the}' could not have taken without the help
of ice. As already suggested, in regions like this, where friable and easily
disintegrated volcanic rocks abound, the amount of erosion whicli has taken
place since the melting away of the ice is quite considerable, rendering it
difficult to connect the isolated occurrences of transported material Avithout

56 GLACIAL AND SUEFACE GEOLOGY OF THE PACIFIC COAST.

a careful survey and an accurate map. Traces of former glaciation were
observed in abundance on the eastern slope, nearly down to Silver Mountain
City, 6,516 feet above the sea-level. Just below that raining settlement
volcanic rocks cover the surface, and no more striation was noticed. It is
probable, however, that the glacier descended considerably lower on this
side, for numerous blocks of granite were seen perched high up on the sides
of the lava-covered ridges, where they must have been left by ice.

The western slope of the Sierra, from Carson Pass nearly to Donner Pass,
or the crossing of the Central Pacific Railroad, a distance of about fifty miles,
is drained by the numerous branches of the American River. For a consid-
erable portion of this distance the summit of the Sierra is divided into two
nearly parallel ranges of about equal height, and between them lies by far
the largest and most important mountain lake of California, Lake Tahoe,
which is about twenty-one miles long, and from nine to twelve in breadth.
The elevation of the range on the west side of this lake, in its highest point,
a little exceeds 9,000 feet. Pyramid Peak, ten miles southwest of the south
end of Lake Tahoe, and just north of the Placerville road to Carscm Valley,
which ascends the South Fork of the American, is the highest point north
of Silver Mountain until we reach Lassen's Peak, having an elevation of
about 10,100 feet, which is nearly 500 feet less than the last-named summit.
The other prominent points along the range at the head of the American
River are nearly a thousand feet lower than Pyramid Peak.* Mount Stanford,
just north of Donner Pass, is 9,102 feet in elevation. Of the passes along
the range between this point and Pyramid Peak the highest is that of Squaw
Valley, crossed by a trail only, and 8,774 feet in elevation ; the pass trav-
ersed by the Central Pacific Railroad is only 7,017 feet above the sea-level.

The point farthest soutli in the American -River basin where traces of
former glaciation have been noticed by the Geological Survey is at Silver
Lake, near Carson Pass, at the head of Alpine Creek, one of the branches of
the South Fork of the American. In fact, the region all about the Carson
Pass, which has nearly the same elevation as the Silver Mountain Pass,
exhibits abundant proofs of the former presence of glaciers. Near Tragedy
Springs boulders of granite were seen resting on the lava tables, as if left
there by ice, although the striation was wanting.

Farther north, all about Hope Valley, and around a small lake in Luther's
Pass, which connects with the Johnston Pass, are abundant glacial traces.

* Sec Table of Daronietrif Altitiules, in Appt'iulix to the gravel volume.

FORMER GLACIATIOX AT THE HEAD OF THE AMERICAN. 57

Around Pyramid Peak extensive ice-flows have existed in former times.
The rock of this lofty peak is all granite, which about the summit covers the
surface in large angular blocks. On the east side is a valley with much bare
rock, which is polished by glaciers, and contains several small lakes. The
large ice-flow which formed on this slope descended to the south, and passed
over a high precipice into the cailon of the American River, a short distance
above Slippery Ford. The name of the latter locality is suggestive of the
glacier-polished surface of the rock at the crossing of the stream.

From Pyramid Peak the range extends in a nearly northerly direction for
about twelve miles, and in the gorges between the spurs leading down
from it to Lake Talioe glaciers formerly descended, probably nearly or
quite to the level of that fine sheet of water, which is about 6,250 feet in
altitude. There is also a high and somewhat isolated point, called Crystal
Peak, five miles north-northeast of Pyramid Peak and at the head of Fallen
Leaf Lake, which also sent down its glaciers to the east and north. In this
part of the range, which runs straight north from Pyramid Peak, a large
branch of the Middle Fork of the American River heads, running northwest
and joining the main stream at Big Meadows. This branch is called the
Rubicon, and its valley is polished and striated throughout its whole length.
The Little Rubicon, a much smaller stream, running nearly parallel with the
last-mentioned, exhibits similar features. According to Mr. Bowman, who
made a detailed survey of this region I'or the California Water Company, the
lowest point at which he observed glacial gravel in the course of his work
around the region drained by the Middle Fork of the American was a little
below Forney's, or Pilot Creek, at an altitude of about 5,000 feet above the
sea-level.

From Burton Pass the main divide of the Sierra trends a little more to
the west of north, and is quite distinctly mai'ked as far north as Mount
Stanford, although declining gradually in elevation. The Twin Peaks and
Granite Chief are two prominent points in this division of the range ; the
former has an elevation of 8,724, the latter of 9,144 feet above the sea. Some
of the higher portions of the ridge are cap[)ed with tables of lava, irregularly
eroded away, as is so common an occurrence everywhere in the range from
the Sonora Pass northward. Glaciers, no doubt, made their wa}- down Ijoth
.sides of this portion of the range. Quite an extensive one must have
descended in the valley of the North Fork; but the upper portion of this
stream has been very little examined by the Survey.

58 GLACIAL AND SUEFACE GEOLOGY OF THE PACIFIC COAST.

Bear Eiver, on the other hand, being near the line of the Central Pacific
railroad, which runs on the divide between that stream and the North Fork
of the American, has been pretty thoroughly explored, and the evidences of
former glacial action traced down to a little below Emigrant Gap, 5,521 feet
above the sea. On the mountain immediately north of Summit Station, at
a point 7,722 feet above the sea, a glacially scratched and polished surface
was observed, indicating that the ice-mass was here not less than 700 feet
in thickness. From the summit down the valley old moraines may be seen
high above its bottom, along the top of which, or near it, the railroad occa-
sionally passes for some distance. At Sereno Lake, where ice is cut for the
supply of the railroad company, the moraine, there very distinctly marked,
was about 400 feet above Summit Valle}^ Near Emigrant Gap the road
is built on the southerly and southeasterly flank of an old moraine of great
size. The top of this is from one to three hundred feet above the line of
the track, the slope descending some 300 feet or more, and in places as
much as 500 feet, to the bottom of the nearest depression, called Wilson's
Ravine. The \ipper portion of the ridge is thickly dotted with granite
and lava boulders as far down as Sailor Ravine, about three miles by the
track below Emigrant Gap. Professor Pettee remarks in his notes of this
region as follows : " It was at the head of this ravine, a quarter of a mile
from the track, that I saw the last granite boulder on this trip. Later in the
season I started from Blue CaSon Station, and found a single piece of gran-
ite about half a mile farther down than Sailor Ravine, at a point nearly due
east from the Blue Canon Station, at an altitude of 5,081 feet. That is the
lowest point at which I saw evidences of the remnants of glacial action.
On the opposite side of Bear River, two miles to the northwest of the rail-
road line, there is a considerable moraine extending down to a probably
somewhat lower level than that just described. But there is no information
as to the precise point to which it descended."

A large extent of country, somewhat lower down on the slope of the
Sierra than that which has already been noticed, was explored by Mr.
Goodyear, as detailed in the preceding pages.* His field of work lay
chiefly between the South Fork of the North Fork and the Middle Fork of
the Middle Fork of the American River ; at least, it was only in the part of
the Sierra between these two streams that he in the course of his explorations

* For details of the route [mssed over by Mr. Goodyear in the course of his exploratious, see page 82, and
accompanying diagram, Plate B. in the gravel volume.

FORMER CxLACIATION NORTH OF BEAR RIVER. 59

reached an altitude great enough to warrant the expectation that traces
of former ghxciation might be met with. The most elevated region exam-
ined by Mr. Goodyear was about the head of the North Fork of the Middle
Fork of the American, where he made several barometric observations at
stations between 5,000 and 7,000 feet above the sea-level. The highest point
reached was Bald Mountain, with an altitude of 7,091 feet.* This region lies
south of the Central Pacific railroad, and nearly west of the upper part of
Lake Tahoe. In spite of its great altitude, however, Mr. Goodyear's notes
do not mention any glacial scratches or polished surfaces as existing in the
region explored by him. A large portion of this district, it is true, is covered
with volcanic debris ; but the valleys are mostly cut down deep into the
granite or slate ; and the rock would in many places have been of a texture
and hardness favorable to the preservation of glacial markings. This is
especially the case in tlie vicinity of the Canada Hill and Bald Mountain
Range, where a kind of quartz-rock predominates, which may be presumed
to have had all the qualities necessary for retaining either striations or
polished surfaces. The reason why the glacier descended to so much lower
altitudes on the line of the railroad, as mentioned above, must have been
that tliere was a more extensive gathering-ground for the glacial mass,
at a high altitude, in the upper basin of the North Fork than there was at
the head of those branches of the Middle Fork which chiefly drain the region
explored by Mr. Goodyear.

From Bear River north no indications have ever been observed, by any
member of the Geological Corps, of extensive glaciation. During the con-
tinuance of the Survey, Sierra County was but very hastily and imperfectly
explored, and the higher part of it was not visited at all'. Plumas County,
however, was examined with some care by the writer, during the summer
of 1866, from Quincy to Lassen's Peak, which forms the extreme northwest
corner of the county. Nowhere in the course of this exploration were any
clearly defined traces of former glaciation observed, in spite of the \evy con-
siderable elevation of the valleys and the surrounding ranges. Even the
higher latitude seems not to have been efficient in aiding to bring about in
this part of the Sierra those climatological conditions necessary to the forma-
tion of glaciers of importance.

During the summer and autumn of 1879 the higher portions of Sierra and
Plumas counties were explored by Professor Pettee, as already mentioned,

* See Ta1)le of Barometric Altitudes, appended to gravel volume.

GO GLACIAL AND SUEFACE GEOLOGY OF THE PACIFIC COAST.

and traces of former glaciation of the region were carefully sought for by
liun. He reports as follows in reference to this point : —

" On the divide between the South and Middle Yubas I saw distinct mark-
ings and polishings of the granite rocks near the Bowman reservoir, at an
altitude of about 5,500 feet. No time, however, was taken for any detailed
examination of this region. The markings seen were all near the reservoir
in the canon ; no note was made of their direction. On the divide between
the Middle and North Yubas, I saw glacial markings on granite near the
head-waters of the North Yuba, at a point about six miles above Sierra City,
and at an altitude of about 5,800 feet. The locality is near the Blue Gravel
location, on Milton Creek, one of the head-Avaters of the North Yuba. The
amount of bed-rock uncovered was not large, but the parallel strife were
exceedingly distinct. Their course was northwest and southeast, bearing
directly for the highest visible point of the Sierra Buttes, about six or eight
miles distant. To the north of the North Yuba I frequently reached alti-
tudes sufficiently great for glacial markings ; but I saw no exposed bed-rodk
which showed signs of being scored and polished. Erratic boulders, difficult
to account for except on the theory of glacial transportation, were seen near
La Porte and Howland Flat. And similarly, near Forest City, south of
Downieville, on the other divide, there were peculiar boulders quite differ-
ent from those which made up the mass of the surface debris. The altitude
at which these last were found was a little less than 5,000 feet ; of the for-
mer, about 5,200. At Jami.son City, the altitude of which is about 5,000
feet, to the northeast of Eureka Peak and the Plumas Eureka quartz-mine,
there is a remarkable deposit of heavy gravel and boulders, none of Avhich
are very much rounded, while some are quite angular. The deposit is a
portion of an extensive range of similar materials, which is said to be trace-
able for several miles along the upper course of the Feather River, towards
Mohawk and Sierra Valleys. Upon the surftice of the gravel there are nu-
merous erratic boulders, as much as ten or fifteen feet in diameter, different
in character from the main mass of the gravel. When exposed to view, a
section of the gravel frequently showed a morainic structure. I was inclined
to the view that the glaciers had considerable to do with the formation of
this deposit, but I could find no further corroborative evidence. The day
after I left Jamison City a heavy snow-storm set in, which prevented my
pushing inquiries any further in that direction. The region to the north
and northwest of the Sierra Buttes — forming the divide between the

FORMER GLACIATIOX ABOUT MOUNT SHASTA. 61

Feather and the Yuba drainage — is one which, in all probability, has been
materially modified by glacial agencies ; but it needs to be visited earlier
in the season. The snow shut me out from it during the first week of
October."

In spite of the very considerable elevation of Lassen's Peak (10,577 feet),
no evidences of former glaciation were obtained in its vicinity either by
Professor Brewer and party in 1863, or by the writer some years later. It is
quite likely, however, that more careful observations might show the exist-
ence near this peak of traces of detrital material which coidd be accepted as
evidences of former glaciation. The character of the rock formations for some
distance around this volcanic mass is not at all suited to the preservation
of striated surfaces.

Somewhat similar remarks might be made about the region adjacent to
the south slope of Mount Shasta. Neither there nor in the valley of the
Upper Sacramento, nor in the elevated plain in the neighborhood of Yreka, on
the northwest of this great volcanic mass, were any evidences of former gla-
ciation observed by the writer. Mr. King, however, in exploring the north
side of the cone, not only discovered active glaciers, but proof that they had
formerly been much larger than they now are. In his account of these dis-
coveries, to which reference has already been made, Mr. King remarks as
follows : "' One of the most interesting of all the features of the country ^va,s,
however, the clearly defined moraines of the ancient and more widely ex-
tended glacier system. Nearly the whole topography of the lower part of
the cone is modified by the deposition of glacial material. At an elevation
of about 8,000 feet on the southern or snowless side of the mountain is a
great plateau-like terrace, about 2,500 or 3,000 feet wide, extending around
one half of the cone, and composed wholly of moraine material. Besides
these, long, straight, or slightly curved medial moraines jut out from the
mountain in all directions, not unfi'equently descending into the valley for
several miles."

This ends what there is to be said in regard to the traces of the former gla-
ciation of the Sierra Nevada, as nothing more of this kind has been observed
imtil we pass to the north of the California line. Not even in the high ranges
of Trinity and Klamath counties was anything seen which would justify the
belief that these mountains, so near the coast, had ever been covered with
ice. Before discussing what has been stated in reference to the glaciation
of regions still farther north, it will be desirable to briefly state what is

62 GLACIAL AND SURFACE GEOLOGY OF THE PACIFIC COAST.

known in regard to the former glaciers of the ranges east of tlie Sierra
Nevada, in the same latitude, and also in the Eocky Mountains.

At the time of the beginning of the California Geological Survey (1860),
nothing whatever was known, at least nothing had been published, in regard
to the former presence of glaciers anywhere in the Rocky Mountains. Our
investigations having made it evident that ice had once covered a consider-
able portion of the Sierra Nevada, and having clearly established the most
important facts connected with this former glaciation along the Pacific coast
as far north as the United States boundary line, it became desirable that
something should be ascertained in regard to the occurrence of similar phe-
nomena in portions of the Cordilleras lying farther east, namely, the Great
Basin Ranges and the Rocky Mountains. Up to the year 1869 nothing had
been definitely made out as to the former glaciation of any part of the Cordil-
leras outside of the limits of California.* It was, therefore, partly for the pur-
pose of obtaining some light on this interesting question that the writer spent
a part of the summer in the highest region of the Rocky Mountains, as already
mentioned. Previous to this, however, he had personally examined several
of the important ranges of the Great Basin, namely, the West Humboldt, the
Toyabe, and portions of the Wahsatch Range. Since 1869, the voluminous
publications of the Fortieth Parallel and the other United States Surveys
have given abundant details in regard to the now well-understood phenom-
ena of extinct glaciers in the region in question, and it is now possible to
miike out pretty clearly what portions of the I'anges were formerly covered
by ice, and how far down their flanks the detrital materials have been carried
by glacial agencies. The deficiencies in our knowledge are most marked in
the northern portion of the Rocky Mountain ranges within the limits of the
United States. Much the larger portion of the detailed work done hy au-
thority of the United States has been carried on in the central and southern
parts of the region in qnestion, or to the south of the parallel of 42°. The
belt of country thus examined, however, includes the higher ranges of the
Cordilleras, whose broadest and highest portion lies between the parallels of
36° 30' and 42°.

* From Dr. Hayden's " Report of the Exploration of the Yellowstone and Missouri Rivers" (1859-CO), pub-
lished in 1869, it would appear that the fact of the detrital material in the Wind River Mountains having every-
where been derived from rocks near at hand had strongly impressed itself on the author's mind. And when it is
said (page 84) that, "on the left bank of Wind River, it would seem as though the icebergs had lodged against
it and quietly deposited the burden of I'ocks which they had acquired in the more elevated mountains," it is
apparent that the intention of the author is to indicate the existence of moraines, and to describe those phenomena
which could only have been due to former glaciation.

FOEMER GLACIATIOX OF THE GREAT BASIN RANGES. 63

The general result of all these explorations is the same as that so clearly
established in California, — namely, that comj^aratively only a very small por-
tion of the highest i-anges of mountains which stretch across that vast region
has ever been covered Avitli glaciers; and, furthermore, as a necessary conse-
quence of this, that there has never been, in this region, anything lil^e a
Northern Drift period, or a transportation of material in any general direc-
tion, independent of the present topograjjhical features of the country.

No traces of former glaciers have been observed in any of the ranges of
Western Nevada, so far as known to the writer. The West Humboldt
Range, the culminating point of which. Star Peak, is 9,925 feet above the
sea-level, shows no signs of former glaciation. In the East Humboldt Range,
on the other hand, the ice-fields were once of considerable size, as reported
by Messrs. Emmons and Hague.* The commanding point of tliis range is
Mount Bonpland, which has a height of 11,321 feet, several other jDoints
reaching over 10,000 feet. According to the authority quoted, the summits of
the East Humboldt Range, from White Cloud Peak to the northern end, all
show abundant evidences of glaciation. In the caiion of the south branch
of the South Fork of the Humboldt River the glacier was eight miles
long. Fifty miles of the range present a pretty continuous area of glaciated
surfaces.

The Wahsatch Mountains also furnish abundant evidences of former
glaciers, but only in their higher portions. According to Messrs. Ennnons
and Hague, such traces are most conspicuous in the Cottonwood region, or
that part of the Wahsatch Range which is included between Utah Lake and
Emisrration Caiion, where the mountain mass is about fifteen miles in width
and over 10,000 feet in average height, the highest point, Clayton's Peak,
reaching an elevation of '11,889 feet. From this dominating peak the main
system of glaciers radiated out, as shown by the topography, as well as by
moraines and the shapes of the caiions. Most of these glaciers, however, did
not descend to a very low level ; but that of Little Cottonwood is thought to
have extended down to the shore of the ancient lake which once filled the
Utah Basin.

There appear also to be some evidences of former glaciers on the Uinta
Range; but, as for as can be judged from the published descriptions of that
region, the area covered by them was not extensive. Messrs. Emmons and
Hague speakf of shallow mountain lakes, occuj^ying glacier-worn basins in

* Fortieth Parallel Survey, A'ol. UI. Descriptive Geologj', pp. 533, u37.
t 1. c, p. 312.

64 glXcial and sueface geology of the pacific coast.

an amphitheatre lying between Bald Mountain and Mount Agassiz. The
average height of the basin is 10,000 feet, and the altitude of the two peaks
named respectively 11,077 and 13,000 feet.

Farther east, in the Rocky Mountains proper, the character and extent of
the former glaciation of the ranges is now pretty well understood, chiefly
owing to the labors of the Geological Survey, under Dr. Hayden's direction.
The entire aspect of the conditions closely resembles that furnished by Cali-
fornia ; everywhere in the highest ranges, under favorable topographical
conditions, glaciers have formerly existed, and have extended down the
slopes of the mountains in the cartons to very considerable distances. Al-
though they have now entirely disappeared, with the single exception already
noted in the Wind River Range, they have left behind them abundant proofs
of their past existence in the usual form of moraines, polished and striated
surfaces, and i-oches moutonnees, similar to those already described as occurring
so extensively in the Sierra Nevada. As in that range, so in the Rocky
Mountains, these remains of tlie work of former glaciers exist, not only on a
grand scale, but in the greatest perfection ; so that, to the eye of the experi-
enced observer, there can Ije no mistake about the nature of the phenomena.
There need be no difficulty in separating the results of aqueous from those
of glacial erosion, and no reason why, in time, the precise limits of the area
formerly covered by ice should not be laid down on the map, just as is now
doing for the Swiss Alps.

At present the northern portion of the Cordilleras is that in regard to
which definite information is most to be desired. The ranges, as a whole,
decidedly diminish in altitude in that direction; but this falling-off is, to some
extent, compensated by the increased latitude.

In the region of South Park, and especially in the Upper Arkansas Valley,
the glacial features are perhaps more striking than anywhere else in the
Rocky Mountains. From all the canons of the Sawatch Range, on the west
side of the head of tlie Arkansas, large glaciers came down, and have left
great morainic accumulations, which extend across the valley in long parallel
lines several hundred feet high. The most conspicuous of these moraines are
those bordering Pine, Clear, and Lake Creeks. The Twin Lakes, nearly at
the head of the valle^y, are enclosed between detrital piles of which the
glacial origin cannot be mistaken. The highest adjacent summits on the
west are a little over 14,000 feet in heiu-ht, the Sawatch being the most
elevated range of the Rocky Mountains ; hence the great development of

FOIIMER GLACIATIOX OF THE EOCKY MOUXTAIXS. 65

the glaciers. These, however, did not descend anywhere in this region to
nearly as low a point as was reached by several of the Californian glaciers.
The upper part of the Arkansas Valley is about 9,000 feet above the sea-
level, and there is no proof that it was ever occupied by ice. Indeed, the
whole series of glacial phenomena in this part of the Rocky Mountains is con-
sistent with itself throughout ; only the highest summits and the most ele-
vated valleys were occupied by the ice. For instance, at the head of South
Park, at an elevation of neai'ly 10,000 feet, just above Fairplay, the valley of
the Middle Fork of the South Platte is barred across by an immense terminal
moraine, 150 feet high, above which was once a large lake, but which has
since been drained off by tlie cutting through of the detrital mass, the ma-
terial of which has been carried down and spread over the valley below by
the rush of water. Nowhere below this point could any traces of glaciation
be discovered over the whole area of the Park ; while above the moraine, in
all the adjacent higher side-valleys and canons, such indications were ex-
tremely conspicuous. The topographical features of the range above Fairplay
Avere highly favorable to the formation of an immense .glacier ; hence the
united stream of ice coming down this branch of the Platte was nearly or
quite equal to the largest of those formed on the eastern declivity of the
Sawatch Range, the breadth and height of which furnished all the necessary
conditions for the accumulation of "laciers of the largest dimensions. Whether
the western slope of the Sawatch Mountains was as favorably situated as the
eastern, in this respect, the writer is unable to state from personal observa-
tion. On the geological map of Colorado, published under the direction of
Professor Hayden, a large moraine is indicated as having its origin in the
canon between Mounts Harvard and Yale, and descending to the west, ter-
minating at an altitude of about 9,500 feet. No other moraines are shown
on the map in any of the ranges directly west of the Sawatch. To the
southwest of this, however, there are several. A small area is indicated as
covered by morainic debris at a locality on the head-waters of Vallecito
Creek, northwest of Mount Oso (13,640 feet). Another is shown at the head
of the Lake Fork of the Gunnison, in latitude 37° 56', at about 9,000 feet in
elevation. Besides these minor glaciated areas, there are two others of more
importance : one of these is near the .sources of the Rio Piedra, south of
Weeminucke Pas.s, on the southwest side of the San Juan Mountains, in
latitude 37° 30' ; the other at the head of Rio Chania, in latitude 37'. These
two last mentioned, which are of interest, since they appear to be the most

66 GLACIAL AiSTD SURFACE GEOLOGY OF THE PACIFIC COAST.

southern indications of former glaciation seen in the Rocky Mountains, have
been described somewhat in detail by Mr. F. M. Endlich.*

The Weeminucke glacier is indicated, on a sketch-map accompanying the
article cited, as having had a length of five or six miles, and there was a
smaller one parallel with it on the northeast, which came down the Huerto
branch of the Rio Piedra. These appear to have descended to about the
same level, — 8,000 feet above the sea. Mr. Endlich describes the glacier
of the Rio Chama as having been of much greater extent than those just
mentioned. It occupied a position on the summit of the volcanic plateau,
at the head-waters of Rio Conejos and Rio Chama. In the ascent of the
latter river the first indications of former glacial activity were met with at
an altitude of 8,450 feet. On the volcanic plateau above, at an elevation of
about 11,800 feet, and higher up for four miles farther north, the rocks are
beautifully striated and polished. The length of the ancient glacier is indi-
cated on the general map of Colorado as about eight miles. Mr. Endlich
says that more than twenty-five square miles must have been covered on the
jjlateau by this extensive mass of ice, which appears to have been chiefly
developed at an elevation of about 12,000 feet, and to have descended to
about 8,000 feet above the sea-level. The above-mentioned occurrences,
and some " small indications of local glacial action " observed in some of the
caiions of the Sangi-e de Cristo Range, of which Mr. Endlich remarks " that
there is no certainty as to their true glacial character," are said by him to
include all the undoubted glacial regions of Southern Colorado that he had
occasion to visit during 1874 and 1875, which were the years when the work
was being carried on in that region. At all events, they are the only ones
indicated on the final map puljlished by the Survey.

Although the geological maps of Colorado, published under Dr. Hayden's
direction, do not indicate the existence of any moraines along the eastern
slope of the so-called Front Range, or that portion of the chain which faces
the Plains, yet there are occasional references in the publislied Reports to
evidences of former glacial action in this part of the Rocky Mountains. A
detachment of the party taken to Colorado by the writer, in 1869, explored
the vicinity of Gray's Peak, which is in latitude 39° 38', and 14,341 feet
above the sea-level. They also followed down Clear Creek to the level of
the Plains at the base of the ramie. Professor Brewer conducted this sub-

o

* In Deport of U. .S. Geological and Geographical Survey for 1875, p. 206, under the head of "Ancient
Glaciers in Sonthern Colorado."

FOiniER GLACIATION OF MIDDLE AND NORTH PARKS. 67

party, and his notes make frequent reference to glacial phenomena observed
along the route. At the base of Gray's Peak distinctly preserved moraines
were observed, but no striations or polished surfaces. Farther down the in-
dication of the former passage of a glacier through the caiion were abundant.
Between Brown's Mills and Georgetown the rocks in the bottom of the valley
are finely polished, and the projecting ledges rounded and smoothed ; there
were also occasional evidences of moraines, although not especially marked
in character. The following passage is quoted from Professor Brewer's notes :
" Some few glacial traces were observed for the first few miles below George-
town [elevation, 8,412 feet], but we saw none whatever below Idaho [7,535
feet]. For most of the distance [from Idaho to the Plains] it was impossible
that an}- considerable glacier should ever have passed down that portion of
the valley since it had its present features. Frequent jagged outliers at
short turns in the valley showed that no glaciers could ever have passed
them and left them in their present shape ; in fact, but meagre traces were
found below Georgetown, and these only for the first five or six miles."

Farther north, about latitude 40° 15', in the Middle Park region, Mr. A. R.
Marvine has indicated the existence of large moraines and other proofs of
former glaciers. The locality is near Grand Lake, in the valley of the North
Fork of Grand River, between the southern end of the Medicine Bow Range
on the west and the Long's Peak Group on the east. The elevation of the
lake is 8,153 feet, and the moraines do not appear to have descended much,
if any, below this level. There are also proofs of the former existence of a
glacier of moderate size, which came down the valley of the East Fork of
the same river, which takes its rise between Mount Audul^on (13,173 feet)
and Arapahoe Peak (13,520 feet).

The phenomena of glaciation in the ranges which enclose the North Park
and extend beyond it to the north as far as the parallel of 42' have been
briefly indicated by Mr. A. Hague.* The Medicine Bow Mountains extend
from latitude 40^ 15' to 4r 40', having an approximate northwest trend.
The western side of this range shuts in the North Park on the east and
nortli, and still farther northward forms the boundary of the North Platte
Valley, which lies between it and tlie Park Range. As thus defined, the
Medicine Bow Range is about a hundred miles in length. Its highest sum-
mits a little exceed 13,000 feet in elevation. All the more elevated regions

* See Eeport of Fortieth Parallel Survey, Vol. II. p. 96, for the Medicine Bow Eauge, and p. 131 for the Park
RauKC.

68 GLACIAL AND SURFACE GEOLOGY OF THE PACIFIC COAST.

of this range exhibit well-marked evidences of glacial action. The summits
of the main peaks are everywhere Avorn in a manner which shows unmis-
takable signs of ice-erosion, and glacial boulders and detrital matter cover
the lesser depressions and slopes. In the region of Medicine Peak (height
12,231 feet), glaciers occupied all the upper valleys. The lowest elevation
reached by these is not expressly stated by Mr. Hague. Near the parallel
of 41° the range has its maximum width of twenty-five miles, and there
two well-defined ridges are developed, the culminating points of which
are Clark's Peak (13,167 feet) and Medicine Peak (12,231 feet). Between
these is a high plateau, nearly 10,000 feet above the sea-level, which is said
to be gently undulating, and without any marked topographical features.
It may, therefore, be inferred that the glaciers did not extend down as
low as this.

In the Park Range, also, of which the highest summits reach an altitude
of a little over 12,000 feet (Mount Zirkel, 12,426 feet, Ethel Peak, 11,976
feet), the traces of former glacial action are abundant " through most of the
higher mountain regions." Mr. Hague notices a fact, which has also fre-
quently impressed itself on the attention of the writer, namely, the great
size of the terminal moraines as compared with the length of the glacier
itself In speaking of the Park Range, he remarks : '' These valleys are
never more than three or four miles in length, and at their mouth, consid-
ering the limited size of the ancient glaciers, are found immense terminal
moraines, which have undergone but little erosion in post-glacial times. It
is as if the entire former contents of the canon had been carried down and
dumped at the entrance, and had never been disturbed."

In following the Rocky Mountain ranges to the north of the parallel of
42°, in order to make out the character and extent of the former glaciated
areas, great difficulties are encountered, as already mentioned, from the want
of any satisfactory detailed investigations in that region. The work of the
four United States Surveys * has almost exclusively been confined to the
southern and southern central portion of the Cordilleras, considerable areas
of which have been gone over by two or even three different organizations.
An exception to this, however, is foiuid in the case of the Yellowstone Park and
vicinity, whose picturesque scenery and most interesting geological features

* The U. S. Geographical and Geological Survey, under Dr. F. V. Hayden ; the Fortieth Parallel Survey,
under Clarence King ; the Wheeler Survey, under the special auspices of the U. S. Engineer Department ; and,
finally, the so-called Powell Survey, the publications of which have been chiefly ethnographic in character.

FOEMER GLACIATIOX OF THE ROCKY MOUNTAINS. 69

have attracted numerous quasi-scientific government expeditions in that
direction. The earlier explorations of the Pacific Railroad Surveys were
extended through the northern part of the Rocky Mountains, but the pub-
lished reports give no infornuition in regard to the phenomena of ancient
glaciers in that region, which fact may be accounted for partly by the igno-
rance and inexperience of the observers, and partly on the ground that
details of this kind had not at that time attracted much attention in the Far
West, the routes of the explorers being almost exclusively limited to the
lower valleys ; their object was chiefly to get across the country as rapidly
and with as little trouble as possible.

Some hints in regard to the existence of former glaciers in the more
northern portions of the Rocky Mountains, south of the United States
boundary, may be obtained from Dr. Hayden's reports. For instance, the
volume giving the results of the explorations of the year 1871, when the
Yellowstone region was visited, by way of Fort Hall in Idaho and Fort Ellis
in Montana, contains the following quotation, which refers to the vicinity
of the range of the Snowy Mountains " forming the great water-.shed be-
tween two portions of the Yellowstone River," a volcanic range rising to the
altitude of from 10,000 to 11,000 feet above the sea-level. Here Dr. Haj'den
describes great detrital accumulations resting against the flanks of the range,
and apparently exactly resembling in character the so-called " washes " of
the California ranges, of which mention has already been repeatedly made.
Of these piles of detritus he .says : " The little streams that flow down from
the mountain sides cut sections through this deposit, so that they are re-
vealed quite clearl}-. The upper portion is composed in part of the debris
from the mountains, but thei-e is all over the valley a vast deposit of what
I can call by no better name than local drift or detritus. In this detritus are
quite frequently masses of rock, or boulders, that have evidently been trans-
ported a considerable distance by a force not now in operation in this vicin-
ity. This fact points back to a time when we may suppose that there were
vast accumidations of snow and ice all over the valleys, but more especially
on the sides and summits of the mountains ; and as the temperature became
much warmer this snow and ice melted, producing rivers and torrents with
sufficient force, aided perhaps by the masses of ice, to move these immense
boulders from place to place. An important fact should be continually borne
in mind, that a critical examination of this detritus reveals no evidence of
the existence of rocks from any distant point outside of the river drainage

70 GLACIAL AND SIJEFACE GEOLOGY OF THE PACIFIC COAST.

in which they ai'e found ; in other words, these superficial deposits are en-
tirely made up of the materials disintegrated from the rocks in the vicinity." *

"We have, in the paragraph above quoted, only indirect evidence as to
the former existence of glaciers in a part of the elevated region higli up
on the- Yellowstone River near the parallel of 44°. The important point,
liowever, in regard to which the evidence is direct, is, that the detrital ma-
terial, with which the slopes of the ranges in that region are covered, is all
of local origin, as is the case in every other part of the Cordilleras of which
mention has been made in the preceding pages.

Although nothing is said in the Eeport from which the quotation given
above was taken about the existence of former glaciers in the region of
the Yellowstone Park, the following may be accepted as a strong indica-
tion that morainic accumulations of detrital material were intended to be
described. In his account of his explorations along the ridge, " in the more
immediate valley of the Yellowstone, near the entrance of the East Fork,"
and not for from the lower end of the Grand Caiion, Dr. Hayden remarks as
follows: " Wiuxt were the forces that wrenched from the parent bed masses
of granite, from one ton to five himdred tons weight, rounded off the angles,
and lodged them upon the plains 300 to 500 feet above the channels of the
principal streams ? Along the East Fork, for twenty miles above its mouth,
on the west side, there is a sort of terrace [a moraine?] about a mile in
width, literally covered with the granite boulders which have been swept
down the valley from a sliort distance above." t

In 1872 the Yellowstone region was again visited by Dr. Ilayden's
exploring parties, and the Teton Range examined and reported on by
Mr. F. H. Bradley, t This range, in whicli there is a group of three lofty
and jagged summits know^n as the Tetons, lies between the parallels of 43^
SO' and 4i\ running nearly north and south along the west side of the head
of Snake River. The height of its culminating summit, Moxnit Hayden, is
stated at 13,858 feet. The valley at its base is a little less than 7,000 feet
in elevation (mouth of Lewis Fork, 6,870 feet; Jackson's Lake, 6,806 feet).
The principal cafions of this range appear, from Mr. Bradley's descriptions,
to have been formerly occupied by extensive glaciers. Great moraines are

* Geological Survey of Montana and Adjacent Territories, 1871, p. 55.
t 1. c, p. 77.

J Deport of the U. S. Geological Survey of Montana, Idaho, etc., 1S72, pp. 190-271. This appears to be the
first Report of Dr. Hayden's in which the words "glacier " and " moraine " occur.

FOEMEE GLACIEES OF THE EOCKY MOUNTAINS. 71

described as coming down into the valley in the vicinity of Jackson's Lake,
and this large body of water itself seems to have been formed, if not by
the actual damming back of the river by glacial agencies, at least by debris
washed down from a series of terminal moraines, now distinctly visible on
the western side of the valle}', the summit of the higlier and outermost
being at an altitude of 3G6 feet above the lake. Jenny's Lake, a little
fixrther south, which lies in the mouth of the Great Canon of the Teton
Range, where is gathered the entire drainage of the western side of the
group of the Three Tetons, is also described as a moraine lake, and at other
caiions in the range similar bodies of water occur. It is i-emarked by
Mr. Bradley, that in spite of the great size and prominence of the terminal
moraines, few remains of lateral ones could be discovered. This fiict
coincides witli wluit was observed by the writer and party at the head of
the South Platte. Another interesting point is, as Mr. Bradley remarks,
that " the water in these mountain streams is now so pure as to make it
certain that not tlie least glacial erosion is now going on at any point on
the ransre."

In the preliminary report of the field-work of Dr. Hayden's parties for the
season of 1878, the latest published document of that Survey which has come
under the writer's notice, it is stated that morainal deposits and glaciated
rocks ai'e shown in the Wind River Range, "on a scale such as we have
not known in any other portion of the West." It is in these mountains
that, as alreadv mentioned, small active glaciers were also discovered bv the
same party. This range, which occupies, so to speak, the summit of the
country, being drained by the head-waters of the Missouri and the Colorado,
lies a little farther south than that of the Tetons. It is a very lofty and
rugged chain of mountains, but the precise elevation of its dominating sum-
mits has not yet been made known ; Fremont's Peak, one of the highest
of them, was roughly measured by the explorer whose name it bears, and
its height given as 13,-370 feet.

The Black Hills, lying between the parallels of 43° and 45°, have been
explored by a government expedition, to which Professor N. H. Winchell
was attached as geologist. The highest point of this range appears to be
Harney's Peak ; its elevation is given at 9,700 feet. Nothing is said in the
official report * of this Survey in regard to past glaciation or the occurrence

* Report of a Eecouuaissance of the Black Hills of Dakota, etc., made iu the Summer of 1S74. By William
Ludlow, Captain of Engineers. Washington. 1S75.

72 GLACIAL AND SURFACE GEOLOGY OF THE PACIFIC COAST.

of drift ill these mountains. The descriptions of the surface convey the idea
most clearly that all the detrital material is of local origin, and that no part
of the surface has ever been covered with ice.

In the preceding pages all that appears to be definitely known in regard
to the former glaciation of the surface within the borders of California, and
ill the Cordilleras south of the United States boundary line, has been jila-ced
before the reader; if not with full details, at least with sufficient minuteness
to afford a satisfactory basis for a discussion of the phenomena in their con-
nection with other evidences of climatic change.

It will be readily seen that the facts are all of a simple character and
entirely in harmony not only with each other, but with the present topo-
graphical features of the region included within the field of observation.
Briefly resumed, these facts are as follows : In California, the Great Basin,
and the Rocky Mountains, up to the head of the Missouri River, the highest
portions of the most elevated ranges were formerly covered with glaciers,
some of which were very extensive, reaching a development of forty miles,
or even more, in length, and of five or six in breadth, — in short, equal-
ling or even surpassing the largest Alpine ice-fields of the present day.
These glaciers nowhere descended to within several thousand feet of the sea-
level. They show a tendency to descend lower as we proceed northward ;
but this tendency is, to a considerable degree, nullified by the diminished
altitude of the ranges, the highest portion of the Cordilleras lying, in Cali-
fornia, between the parallels of 36° and 39°, and widening as it crosses the
country, so that its northern limit in the Rocky Mountains is a little beyond
the parallel of 44°. No proofs whatever of former glaciation have been de-
tected by competent observers to the south of latitude 36°. All through the
region indicated the detrital materials have been carried from the higlier
toward the lower areas, in strict harmony with the present configuration of
the country. A large part of this carrying has been done by water unaided
by ice, for the formerly glaciated area occupies but a very small portion of
the surface. Where glaciers have existed, there all the signs of their former
presence, such as moraines, striated and polished surfaces, and rounded ledges,
can be recognized without the slightest difficulty, so that, with accurate
maps and careful observations by competent persons, the area forme ily cov-
ered by ice could, and probabl_y will at some future time, be laid down with
the closest approach to accurac}-. And, of course, from wliiit has been said
above, it will be readily perceived that there is no such thing as " Northern

ABSENCE OF NORTHERN DRIFT; STATEMENT MADE IN 1866. 73

Drift " anywhere in the region covered by the observations in the preceding
pages.

It was after some years of exploration in Cahfornia and along the Pacific
Coast, by the State Geologist and other members of the California Geological
Survey, that the writer published, in ] 866. the following statement in regard
to the absence of the Northern Drift formation from the western coast of
North America and from the interior of the continent, throuo'hout the region
to the southwest : * —

" The explorations of the Geological Survey of California have demon-
strated, however, that there is no true Northern Drift within the limits of
this State. Our detrital materials, which often form deposits of great extent
and thickness, are invariably found to have been dependent for their origin
and present position on causes similar to those now in action, and to have
been deposited on the flanks and at the bases of the nearest mountain
ranges by currents of water rushing down their slopes. While we have
abundant evidence of the former existence of extensive glaciers in the Sierra
Nevada, there is no reason to suppose that this ice was to any extent an
effective agent in the transportation of the superficial detritus now I'esting
on the flanks of the mountains. The glaciers were confined to the most
elevated portions of the ranges, and although the moraines which they have
left as evidences of their former extension are often large and conspicuous,
they are insignificant in comparison with the detrital masses formed by
aqueous erosion. There is nothing anywhere in California which indicates
a general glacial epoch, during which ice covered the whole country and
moved bodies of detritus over the surface independently of its present con-
figuration, as is seen throughout the Northeastern States.

" The same condition of things prevails in Nevada and through Oregon, as
far as explored by the members of the Survey. The detritus seems always
to be accumulated at the base of the mountains, — gravel, boulders, and
sand lying below and not far distant from the beds of rock of which these
materials once formed a part, and from which thej^ appear to have been
detaclied by weathering and aqueous erosion.

" From the observations of Messrs. Ashburner and Dall, it would appear
that no evidences of Northern Drift have yet been detected on this coast,
even as fir north as British Columbia or Russian America. Neither of these
gentlemen has observed any indication of a transportation of drift materials

* Proceedings of the California Academy of Sciences, Vol. 111. [J. 271.

74 GLACIAL AND SUEFACE GEOLOGY OF THE PACIFIC COAST.

from the north towards the south, or of any condition of things similar to that
wliich must have existed in the Eastern States during the diluvial epoch.

" On examining the published records of explorers in the central portion
of the Continent, it will be noticed that there is strong reason to believe that
the absence of the Northern Drift formation is not peculiar to the States
along the Pacific Coast ; but that the whole region west of the Eocky Moun-
tains is also destitute of any indications of a detrital formation moved over
the surface in one direction by any gi-eat general cause. Judging from our
present stock of evidence, I am inclined to draw the line which limits the
Northern Drift formation on the south and west approximately from the
mouth of the Ohio to the head-waters of the Saskatchewan River."

The above-quoted communication in regard to the character of the drift
deposits on the Pacific Coast has been the subject of repeated severe criti-
cisms in various scientific journals at home and in Europe. The subject
is an interesting one as bearing directly on a question of much interest,
namely, whether the so-called Glacial epoch was of a general, or only of a
local character. It is true, however, that tliis question has not now the
importance which it had when the above-quoted communication was made
to the California Academy. Since that time it has been clearly established,
by extended investigations made in Europe and Asia, that the idea that
the phenomena of the drift are due to a general North Polar ice-cap is
entirely unsupported by facts, as will be more fully explained further on.
Nevertheless, the conditions of the Glacial and Northern Drift epochs in
North America are so complicated, that everything which can throw light
on the various forms and stages of their development is worthy of a careful
setting forth.

As far as California and the mass of the Rocky Mountains south of the
immediate vicinity of the United States northern boundary line are con-
cerned, the facts are so clear that there can be no dispute, and need be no
discussion, about them. Enough has already been said in the preceding
pages on this point, and there is no occa.sion to alter anything stated in the
first of the paragraphs quoted above.

In regard to the former glaciation of Nevada and Oregon, included in the
second paragraph, little needs to be added. The condition of things in
Nevada has already been set forth, in connection with the other portions of
the Great Basin. Nor is there occasion to dwell long on Oregon. That State
has been sufficiently examined, both by the writer and by Mr. Gabb, to justify

FOEMER GLACIATIOy OF OREGON". , 75

the assertion that the same conditions hokl in tlie Cascade Range as farther
south in tlie Sien-u Nevada. There is no such thin<>: as Northern Drift in
the State, a ver\' large jDortion of which is covered by ahnost bare, horizontal
overflows of basaltic lava. As there is no map of the mountains of Oregon
approximating even to correctness, it will be impossible to make any more
definite statement than this : That the higher points between Mount Pitt
and Mount Hood have formerly, in all probability, had each its system of
glaciers ; but that these could not have been large, because the range is
low and the crest narrow, the elevated points being nearly or quite isolated
volcanic cones, around which the ice-masses chiefly formed. Di". Newberr}''
explored the region around the base of the Three Sisters, in latitude 44°,
and saj^s, in describing a volcanic cone a little to the south of that group, that
the rocks of which it is composed are everywhere cut by deep furrows, which
in all cases pointed towards the centre of the mountain mass. Having crossed
the main ridge north of the Tliree Sisters, " the same phenomena were
noticed, extending down to the altitude of 4,459 feet, where they terminated
in a deep canon, through which a stream flowed into the Willamette Val-
ley." * The altitude of the loftiest of the group is given by Dr. Newberry
at from 10,000 to 11,000 feet; the height of the base from which it rises is
not stated, but it appears to be about 5,600 feet. The scratches and furrows
on the surface of the volcanic rocks are said to extend down to 2,500 feet
below the present snow-line, and everyAvhere to be directed toward the
highest point of the adjacent lofty grouj^ of peaks.

If further evidence be needed, it may be found in the latest published
work of the author of Frost and Fire, an enthusiastic glacialist, who vis-
ited Oregon a few years ago. He says, in speaking of the Cascade Range
and the vicinity of Mount Hood, " As for glacial marks, there are none." t

That the present glaciers of Mount Hood were once of considerably larger
size than they now are, is vouched for by Mr. A. Hague in the following
words : t " One of the most remarkable geological and topographical features
of Mount Hood and the vicinity is its very extensive system of extinct
glaciers, which everywhere gouged out immense ti-ough-shaped valleys,
cutting down deeply into the earlier trachytic lava-flows of the old volcano.
The entire network of valleys were all connected with two main glaciers, —
that of Hood River on the north, and the Sandy on the south. The ancient

* Px'port of Pacific Ruilroad Surveys, Vol. VI. p. 41.
+ My Cii-cular Notes, by J. F. Campbell, Vol. I. p. 95.
t Am. Journal of Science, Third Series, Vol. I. p. 167.

76 GLACIAL AND SUEFACE GEOLOGY OF THE PACIFIC COAST.

White River glacier was undoubtedly very large, but, as far as my observa-
tions have yet extended, had no tributaries."

Passing across the Columbia River into Washington Territory, we find a
condition of things prevailing similar to that which exists farther south.
There is no drift other than that which is local in character, as the writer is
able to affirm from personal examination. No doubt the ice-masses of the
great volcanic cones of that Territory were once larger than they now are ;
at least, reasoning from analogy, we have every reason to believe that would
have been the case. Mr. Emmons, however, in his preliminary report on
the exploration of Mount Rainier, to which reference has already been made,
makes no mention of any proofs of a former more extensive glaciation in
that region.

As far, then, as the second paragraph of the communication made by the
writer to the California Academy, in 1866, is concenied, there is no reason
whatever for any change in what was said at that time. That there may be
evidences that a portion of the country adjacent to Puget Sound has been
submerged under the ocean at a not very distant epoch, and that, as a con-
sequence of that submergence, icebergs may have left scattered accumula-
tions of debris in such places, cannot be denied. It is not true, however,
that glaciers formerly extended over this region, or that the mass of the
detrital material on the surface came from the north.

- Passing next to the region north of the boundary of the United States,
we have to depend largely on the observations of others, and an attempt
will be made to sift the evidence offered, in order to make out whether that
part of the Continent presents features of glacial geology essentially different
from those existing within our own borders. And for this purpose it will
be convenient to begin the pi'oposed examination with the prolongation of
the Rocky Mountain ranges in the vicinity and north of the parallel of 49°.

The first authority that one would naturally be inclined to consult is the
geologist attached to tlie Palliser Expedition, which carried on an extensive
exploration of the eastern division of the Cordilleras, or the Rocky Moun-
tains proper, during the j^ears 1857-18G0. Their routes extended over that
portion of the mountain system which lies between the parallels of 47° and
53°, or the region drained to the east by the numerous branches of the
Saskatchewan and the Athabasca, and to the west chiefly by the Columbia,
but also in part b^^ the head-waters of the Eraser. Dr. Hector, the geologist
attached to this important expedition, was evidently quite inexperienced,

FORMER GLACIATIO^ IN THE ROCKY MOUNTAIXS. 77

as has been shown in another place,* so that his statements must be
received with some caution. He nowhere, in his official report, speaks of
any phenomena of former more extensive glaciation, or of any accumu-
lations of the " superficial deposits," as he calls the most recent formations,
as having the character of moraines. He considered that he had obtained
proofs that the continent was depressed, dming the Northern Drift period,
to a depth of nearly 3,000 feet beneath a sea in direct connection with
the Arctic Ocean, and that since then, to use the author's own words," during
its gradual emergence, the prairie region of North America has received its
present form of surface by denudation, first, as effected on sea-coast lines ;
secondly, by the coast-lines of great inland lakes, which, it will be shown,
though still existing, were previously of much greater dimensions ; and,
thirdly, by atmospheric agencies wearing away the soft strata, aided by
streams." Dr. Hector speaks of the "glacial markings" on the rocks of
Vancouver Island, to which reference will be presently made. He saw soli-
tary boulders of great size resting on the '•' shingle terraces " — and by tliis
term he evidently means the local drift accumulations — " in the woods to
the south of Fraser River," at a height not more than 100 or 200 feet above
the sea-level. In his final summing up of the drift phenomena of the Pacific
Coast, he remarks as follows : " As I never observed drift or boulders within
the Cascade Range, even in places elevated only 600 or 700 feet above the
sea, but as all the superficial deposits in the great trough between that range
and the Rocky Mountains clearly are formed from the re-arranged materials
of the shingle terraces, along with tufas from the Cascade Range, I conclude
that the average lowest altitude of the Cascade Range, which is somewhere
about 4,000 feet above the sea at the present time, exceeded the depression
of the continent during the glacial epoch, and presented a barrier to the
causes which transported the erratics and scratched the rock-surfaces along
the Pacific Coast. If the Cascade Range at that time formed a jjrom-
ontory enclosing a gulf open only to the south, like the Gulf of California,
it would exactly fulfil these conditions."

In regard to the former glaciation of the Rocky Mountains, where crossed
by the boundary line, in latitude 49^, we have the statements of Mr. G. M.
Dawson, the Geologist of the British North American Boundary Commission,
who speaks of the effects of glaciers as being frequently apparent along his
route. The descriptions given, however, do not convey the idea that the

* See Auriferous Gravels of the Sierra Nevada of Calilbruia, pp. 69, 70.

78 GLA.CIAL AND SURFACE GEOLOGY OF THE PACIFIC COAST.

phenomena are particularly well-marked, or on any large scale. At Chief
Mountain Lake, 4,213 feet above the sea, near its northern end, a " collection
of rounded and hummocky hills " is thought by him to prove the former
presence of large glaciers, although the hard limestone over which it must
have pa.ssed showed no signs of striation. The only place where glacial
striation was actually observed was in the Valley of the Kootanie Pass, where
the surface of the hard green slate had markings upon it coinciding in direc-
tion with the main trouo;h of the vallev. Moraines are described as existing
farther up the valley, neither the locality nor the elevation being given
with any degree of precision *

From the character of the evidence presented by Mr. Dawson, together
with that furnished by Dr. Hector, it may be j^retty safely concluded that
the Rocky Mountains in their extension north of the parallel of 49" do not
exhibit any very remarkable indications of former glaciation. This inference
would be corroborated by the account furnished by Mr. Selwyn, Chief of the
Canada Geological Survey, of an expedition to the head of Peace River, at
a considerably higher latitude than the region visited by the Palliser Expe-
dition. Mr. Selwyn, as previously mentioned, saw no glaciers or permanent
snow in tliat region, neither does he make any mention of traces of former
glaciation in tliat portion of the chain examined. At all events, there is no
evidence anywhere in the Rocky Mountains, either to the north or to the
south of the boundary line, of a transportation of detrital material in any
general direction independent of the present topography.

Between the Rocky Mountains and tlie Cascade Range in British Columbia
is an extensive area of country drained by the Fraser and Columbia rivers
and their numerous branches, both of which streams run, for a long distance
from their sources, in a northwesterly direction, then turn abruptly and pursue
a parallel course in the opposite direction.! The region thus included be-
tween the two principal divisions of the Cordilleras is far from having Ijeen
mapped with any approach to accuracy, but its most striking topographical
features are pretty well known in a general way. It is l)y no means a level
country ; on the contrary, it is everywhere rugged and even mountainous,
although the irregular ranges do not appear to attain anywhere an elevation
equal to that of the dominating points of either the Cascade or the Rocky

* Report on the Geology and Resources of the Region in the Vicinity of tlie Forty-ninth Parallel. Montreal,
1S75. p. 245.

t The Columbia River rises near the parallel of 50°, awl runs northwest to a little beyond 52°, where it joins
the Canoe River, coming from e.xactly the opposite direction and heading near 53°.

THE TEIiEACES OF FEASER EIVER. 79

Mountains. The interesting features of the region in question are the Lake-
like expansions of tlie rivers, and the remarivable reguhirity and develop-
ment of the terraces -with which lakes and rivers are almost everywhere bor-
dered. Some of the streams are almost unbroken lines of narrow lakes with
short connecting river portions between ; as, for instance, the Columbia and
the Okana^an. The general direction of these lakes is either parallel to that
of the enclosing ranges or at right angles to it. A glance at a map of Brit-
ish Columbia will show better than words the position and the peculiar
orographic development of these wonderful expansions of the rivers.

The terraces of Fraser River and its affluents have been repeatedly noticed
by scientific explorers and other travellers, although not as yet described
with accuracy.* These terraces, or benches as they are usually called in
that region, seem to be found almost everywhere on the Fraser and Columbia
and their branches. They are often very numerous, there being near Lil-
louett, for instance, as many as fifteen or sixteen. Some observers notice the
fact that for a long distance on the main Fraser there are three such
benches, of exactly similar height on each side of the river, the highest of
which is about 500 feet above the present level of the water.f Although it
seems to be nowhere positively stated that these benches slope Avith the
bottom of the river valleys along which they occur, there can be no doubt
that such is the fact. Like all, or almost all, such terrace formations, they
are the indications of a former higher stage of the water in the streams.
The country has been gradually relieved of a portion of its surplus water,
not by its elevation above the sea-level having been increased, as is often
supposed, nor by the bursting of successive barriers along the course of the
vallej-s, a theory even less tenable than the other; but simply because the
quantity of water now passing down these valleys is fiir less than it formerly
was. This condition is in entire coincidence with all the facts developed by
geological investigation on the Pacific Coast, as has already been abundantly
set forth in the volume devoted to the Auriferous Gravels.

The questions which at present concern us particularly are, whether there

* See Report of Progress of Geological Surve)- of Ciuiaila for 1S71-72, p. 5.t ; Milton and Cheadle, The
Northwest Passage by Lanil ; G. JI. Dawson, in Quarterly Journal of the Geological Society, Vol. XXXIV. p. Ill;
Proceedings of the Royal. Geogi-aphical Society, Vol. XV. p. 133, where a paper on these terraces, wiitten liy II. R.
Begbie, will be found, together with aj^pended remarks by Dr. Cheadle and others.

t Mr. G. M. Dawson claims to have founil terraces at much greater elevations. He says "the highest perfectly
distinct line was estimated to reach l,.5(iO feet," that is, above the level of the river. This detrital accumulation
he thinks may possibly have been an old moraine " of a great glacier which has filled the valley."

80 GLACIAL AND SUEFACE GEOLOGY OF THE PACIFIC COAST.

are any proofs that the valleys of the region in question are filled with de-
trital materials of other than local origin, or Avhether there is anything in
the character of the surface geology radically difierent from what has been
observed in the ranges and valleys to the east and south. As far as can be
made out from published documents, there is no reason whatever to suppose
the previous existence of any other than small local glaciers (if any at all)
in the region at the head of the Fraser and Columbia ; neither is there any
evidence that the drift is not of local origin. The form of the cross-sections
of the valleys, as revealed in photographs and drawings taken at various
times, shows clearly that there is almost invariably a steep slope of the
detrital material downward from the enclosing moimtain ranges towards the
rivers, and this is abundant evidence that these materials came from the ad-
joining elevations, and that they in fact are exactly similar to the ordinary
slopes of detritus, or " washes," with which we have already become familiar
as occurring; on such a larije scale in California and the Great Basin. It
is true that Mr. G. M. Dawson, in entire contradiction to all the flicts, as the
writer thinks, believes it possible that glaciers may once have filled these
valleys.* The observations and theories of this observer will be referred to
and discussed further on. He seems, however, not wholly to reject the view
maintained above in regard to the real character of these terraces, for he
says: "In some cases they [the terraces] may show merely stages in the
descent of the rivers to their present levels through the wide-spread de-
posits of the Glacial period."

The statements made by the writer in the quotation given above from the
California Academy's Proceedings, seem to be entirely borne out by an over-
whelmino- weio-ht of evidence, for the whole area embraced within the Cor-
dilleras, with the exception of the portion which remains yet to be inquired
into, namely, the ranges bordering the coast in British Columbia from Van-
couver Island northward. To this region the attention of the reader may
now, therefore, be called. At the time the article in question was written,
or fourteen years ago, almost nothing was definitely known of the character
of the coast north of Oregon. The investigations of the writer and Mr. Gabb
on Vancouver Island and up the Fraser Ri^•er were necessarily of the nature
of hasty reconnaissances.t Mr. Ashburner, formerly of the Geological Survey

* Mr. Dawson admits, however, tliat the lienches in question " look like shore-lines, caused by tlie accunuilatiou
aud horizontal arrangement below the water-line of debris from tlie mountain slopes."

t The prineipal object of Mr. Gabb's visit to Vancouver Island was to fi.K the age of the coal of that region :
that of the wiiter was to learn something of the surface geology of the northwestern portion of our territory.

ABSENCE OF PROOFS OF FORMER GLACIATION IN ALASKA. 81

of California, had also visited Queen Charlotte Islands to examine the coal
deposits, supposed at one time to be of great importance. Mr. Dall had
begun his valuable explorations of Alaska, which have been continued since
that time, and of which the results have been published in part.* • From
verbal communications made to the \yriter by Messrs. Ashburner and Dall
previous to the publication of the article in question, the writer was led to
consider that the conditions previously ascertained by the Geological Survey
to exist in reference to the occurrence of the Northern Drift in California,
Nevada, and Oregon were very likely to prevail all along the coast and
within the limits of the Cordilleras generally, far towards the Arctic Ocean.
Much opposition has been made to this view ; but that which, in 18G6, was
perhajis rather a hazardous conjecture can now be supported b}' an abun-
dance of evidence. Indeed, tlie statement as put forth by the writer was
unaccompanied by any positive assertion, except for the regions which he
himself had explored. A full discussion of the relations of the glacial phe-
nomena of the Pacific Coast to those of the Northeastern States cannot, how-
ever, be satisfactorily entered upon until later in the present volume. What
remains to be done now is, to set forth what has been observed by various
explorers in regard to the glaciation of the Pacific Coast and the Coast
Ranges north of Vancouver Island.

For the extreme northern portion of the region in question we have, so
far as the writer knows, no other trustworthy authority than that of Mr.
Dall, whose work on Alaska, published in 1870, embodies the results of
several years of research in that part of the country. Mr. Dall in this
volume.! after quoting that portion of the article published by the present
Avriter in the Academy's Proceedings which relates to the absence of the
Northern Drift from the Sierra Nevada and the local character of its detrital
accumulations, says, " The same is eminently true, as far as we know, of
Alaska." Further on he adds, "Nor in my own observations in the vicinity
of Sitka and the peninsula of Aliaska have I met with any cases of this most
characteristic phenomenon of general glacial action. If the glacier field once
extended over the entire coast, previous to the formation of the archipelago,
we may conclude that the more northern portions of the territory, north of
the Alaskan Mountains, would not have been exempt from glacial action.

* See AIa.ska ami its Resources, Svo, Boston, 1870; and the Pacific Coast Pilot — Alaska ; Appendix, Meteo-
rology and Bibliograph}-, 4to, Washington, 1879 ; both works by W. H. Dall, of the U. S. Coast Survey,
t Alaska and its Resources, pp. 461, 462.

82 GLACIAL AND SUEFACE GEOLOGY OF THE PACIFIC COAST.

Three years' exploration, with a strong disposition to develop the flicts of the
case, failed to obtain on the shores of Norton Sound, or in the Valley of the
Yukon, any evidence whatever of such action. Only once were polished
rocks met with, and they proved on examination to be ' slicken-sides ' ;
while no instances of transported materials, scratches, boulders, or moraines,
were anywhere met with. The rolling and moderately elevated character
of the country does not favor the development of local glaciers, such as
now exist on the more southern coasts of Alaska. Thomas Simpson espe-
cially remarks the absence of drift boulders on the Arctic Coast, west of
Return Reef of Franklin. These most characteristic evidences of glacial
action, which a child could not overlook, are quite absent in the Valley of
the Yukon."

Here, then, we have trustworthy evidence of an explorer whose attention
had been especially directed to this subject, to the effect that no Northern
Drift could have originated in higher latitudes and made its way to the
south. If there is in any portion of the Coast Ranges of British Columbia
drift which has come from the north, it must have originated or started from
a point south of Alaska. In other words, somewhere within the ranges in
question the detrital materials must have assumed a character quite different
from what they have anywhere else in the Cordilleras, and have been swept
in a direction longitudinal to the crests of the mountains instead of from
them toward the valleys lying between them.

The principal evidence in favor of the occurrence of material carried
southward and of striated surfaces indicating a former general glaciation of
the surface independent of the present topography, is supposed to have been
obtained on Vancouver Island, the statements in regard to which vary con-
siderably. All observers, the writer among the number, have noticed the
glaciated rocks in the vicinity of Victoria.* There can be no doubt that the
southern end of the island has been passed over by ice ; but it is not so
certain whether this was in the form of the glacier or the iceberg. The
writer, who by no means claims to have made an exhaustive exploration of
the island, saw glacial scratches on the surface near Victoria, and along tlie
shore for some distance above. These markings, however, seemed to him to
be of the character of those made by icebergs rather than by glaciers. Tliey
were especially prominent along the projecting points of rock, and every-

* Mr. Campbell says, "I found glaciated rocks on the shore, and I was happy in Victoria." Jly Circular
Notes, Vol. 1. ).. 102.

GLACIAL MAPtKIXOS ON VANCOUVEE ISLAND. 83

where ptirallel with the coast. If there was a fixed mass of ice there, it must
have been a glacier coming down the straits, and not one descending from
the hioher parts of the ishmd. On ascending to the higher land a few miles
north of Victorin, the glacial markings were found not to extend up to any
great height : none were seen at an elevation greater than a hundred feet.
At one point, at an elevation of 150 feet above the sea, an angular fragment
of granite eight feet long and high, and about six broad, was observed lying
upon a surface of metamori)hic rock, which was not in the slightest degree
smoothed or polished. The impression made upon the writer by an examina-
tion, necessarily hasty, of the southern end of Vancouver Island was, that all
the phenomena presented in that vicinity could be best accounted for by the
supposition that large icebergs had passed down the Straits at a time when
the glaciers coming down the coast farther north were considerably larger
than they now are, and that these bergs had dropped occasional boulders on
the surfoce, and had here and there produced those striations which are
abundantly vouched for by Arctic explorers as being often made at the pres-
ent day by floating ice. This tlieorj' presupposes a slight elevation of the
land in that region since the time of the greatest extension of the glaciers,
and such a rise is quite in harmony Avith facts observed at many points on
the coast forther south. Mr. Gabb also noticed the glaciation near Victoria,
but his notes make no reference to any such phenomena in the vicinity of
Nanaimo. Mr. H. Bauerman* also speaks of the scratched and grooved
rocks in the vicinity of Esquimalt and Victoria, but does not mention their
occurrence anywhere else on the island. Mr. J. F. Campbell says : •' As soon
as I spied the rocks at Victoria, I recognized the familiar glaciated form.
The direction of movement was parallel to the axis of Puget Sound, at right
angles to the strait which opens into it from the Pacific Ocean. It follows
that all this water drift, with rare glacial boulders in it, rests upon glaciated
rocks. Because of shells found in the drift, the glacial period here was
marine." Mr. Selwyn also noticed the appearances at Victoria,! and says :
" Of the existence of ice-grooves on the shore of Vancouver Island there can
be no question. Inland neither Mr. Richardson nor I observed any."

There is considerable evidence, on the other hand, that Vancouver Island
has been the theatre of a much more extensive glaciation than would be in-

* In an article entitled, "On the Geology of the Southeasteru Part of Vancouver Island," Quarterly Journal
of the Geological Society, Vol. XVI. p. 198.

+ Geological Survey of Canada. Report of Progress for 1S71-72, p. 53.

84 GLACIAL AND SURFACE GEOLOGY OF THE PACIFIC COAST.

ferred from the authorities cited above. Two observers have been especially
active in this direction, and have published their views on the subject at
considerable length ; these are Mr. G. M. Dawson, to whom reference has
been previously made, and Dr. R. Brown, who devoted a part of the years
1864 .and 1866 to an official scientific examination of the island.* The titles
of the papers published by the last-named explorer, in which the subject of
Northern Drift is discussed, are given below ; but the last one published,
namely, the one in the American Journal of Science, will be chiefly used in
this connection, as containing the latest and fullest exposition of his views.
In this paper Dr. Brown remarks as follows: "So for from the Northern
Drift being absent from Vancouver Island and British Columbia, it is present
in as marked a manner as ever I saw it in countries celebrated for the
presence of such remains." This is much stronger language than had been
previously used by the same observer in a communication published some
years earlier, and immediately after the completion of his woik on the island.
In that statement he speaks only once of glacial and drift phenomena,
and that in a chapter of his communication which is credited to other per-
sons, it being stated at its beginning that it was compiled from accounts
furnished by four of his employes, who appear not to have been scientific ob-
servers, one of them at least being an Indian guide and hunter. t The para-
graph in question reads as follows, in an English translation: "These hills
appear to be made up of masses of Plutonic rock, covered with a thin layer
of humus, here and there strewn with erratic blocks, -wliich form a j^art of
the Great Northern Drift formation, to be found all over Vancouver Island.
Indeed, some of the principal edifices of Victoria are built of a gray syenite
which is not to be found in silii nearer than Alaska." It is hardly necessary
to call attention to the extraordinary character of this last statement, ^lut
forth by one who had never made any detailed examination of the country to
the north.t A similar disregard to scientific accuracy of statement will be

* See Mr. Dawson's paper "On the Superficial Geology of Britisli Columbia," Quarterh- Journal of the Geo-
logical Society, Vol. XXX IV. p. 89.

Dr. Brown's principal papers are : Das lunere der Vancouver Insel, in Petermann's Mittheilungen for 1869,
p. 1 ; On the Geographical Distribution and Physical Characteristics of the Coal- Fields of the North Pacific
Coast, in Transactions of the Edinburgh Geological Society, Vol. I. p. 305 ; On the Supposed Absence of the
Northern Drift from the Pacific Slope of the Rocky Mountains, in the American Journal of Science, Second
Series, Vol. L. p. 318.

+ See Petermann's Mittheilungen, 1869, p. 4.

X All that Dr. Brown had seen of the region to the north of Vancouver Island seems to have been comprised in
a hasty visit to the Queen Charlotte Islands.

GLACIAL MARKINGS ON VANCOm'EE ISLAND. 85

found pervading the wliole article in question. For instance, it is remarkable
that no clew is given to the heights at which the erratic blocks actually
observed were seen; neither is there any precise statement of locality in
Dr. Brown's connnunications, excepting the three-times repeated information
in regard to the granite of which some buildings at Victoria have been con-
structed. There is nothing in either of the three papers whose titles have
been given which is inconsistent with the idea previously advanced by the
present writer, that icebergs have passed over portions of the island and
dropped occasional boulders on the surface, at a time when the level of the
land was not as high as at the present time by one or two hundred feet. This
indeed might seem to be the idea of Dr. Brown himself, who thus expresses
himself in speaking of the Victoria erratics: "I am not aware that any rock
of a similar description is found «n situ anywhere in Vancouver Island [this
is rather different from the former positive assertion that no such rock could
be found in place south of Alaska] ; it appears to have drifted in icebergs
fioni the north." Dr. Brown quotes Mr. Bauerman as authority for the occur-
rence of " true glacial or boulder clay in various portions of Vancouver
Island" ; but the truth is, that this geologist, as already mentioned, describes
nothing of the kind except at Victoria and its immediate vicinity. And, in
addition to this, it is from Mr. Bauerman himself that we have the impor-
tant statement of the finding of marine shells in the so-called glacial drift, —
a sufficient indication, one would suppose, that here could be no question of
glaciers proper, but rather of iceberg agencies. Dr. Brown was evidently
at the time he visited Vancouver Island an entirely impractised observer.
There is a vagueness about all his geological data, which makes it quite
impossible to use them in arriving at definite conclusions in regard to the
former glaciation of the northwest coast.

Mr. G. M. Dawson, in his already quoted paper, gives a much more definite
account of his observations on the glaciation of Vancouver Island than does
Dr. Brown of those made by himself and party. Mr. Dawson, however, like
almost all other geologists who have visited the island, confines his remarks
principally to the neighborhood of Victoria. Indeed, he gives no positive
statements of any kind in this connection except for localities in the im-
mediate vicinity of that citv'. The highest point at which he professes to
find glacial markings is on the summit of Mount Douglas, or Cedar Hill, a
rocky eminence G96 feet high, but even here he himself admits that there
is some uncertainty, for he remarks that " the direction of the glaciation " is

86 GLACIAL AND SURFACE GEOLOGY OF THE PACIFIC COAST.

due south, as nenrlij as can be ascertained. There is no difficulty in .iscertaining
the direction of striaj which are well defined, as everj^ geologist knows.

Mr. Dawson confirmed the investigations of Mr. Bauerman to a certain
extent, by finding marine shells in several localities in the so-called glacial
drift. It is a little curious that the points where these discoveries were made
are not stated ; but from tlie context they would appear to be in the im-
mediate vicinity of Victoria. His theoretical results are given in the follow-
ing words: "There appears to be no escape from the conclusion that a
glacier swept over the whole southeastern peninsula of Vancouver Island at
some time during the Glacial period ; and on consideration of the physical
features of tlie country it becomes apparent that the entire Strait of Georgia
between the island and the mainland must have been filled with a threat
glacier, with a width in some places of over fifty miles, and a thickness near
Victoria of «< least considerably over 600 feet." This last statement of thick-
ness seems to depend entirely on the single observation on Mount Douglas,
previously referred to, confessedly of an unsatisfactory character, and in con-
flict with the observations of the present writer, as well as those of Messrs.
Selwyn and Richardson of the Canada Survey. Mr. Dawson himself appears
to be struck b}^ some of the difficulties in the way of the adoption of his own
theory, for he adds immediately after the lines above quoted : " With all
this, however, there has been very little general wearing-down of the rock-
surface of the country ; all its main features, and, in man// cases, even the most
minute [the italics are the present writer's modification of the original] are
clearlji of preglacial origin. The vallej's generally follow bands of limestone
and softer schistose and slialy beds, and run as often transverse to, as parallel
with, the direction of glaciation ; and besides the general forms of the smaller
hills, little rocky knolls and projecting points of rock, while worn and
rounded to the north, preserve rough unpolished southern faces. This
feature is uiore marked than I have elsewhere observed, and would seem to
indicate, even allowing that glaciers do not very rapidly abrade solid rocks,
that the ice did not long rasp over this portion of the country, and possibly
that it never extended much beyond this point."

It is surprising that Mr. Dawson did not see how much better the theory
of iceberg agencies would ailapt itself to an explanation of the above de-
scribed phenomena, than the one which he adopts, namely, that of a great
glacier wdiich has no apparent head, and which comes to a sudden stoppage
when 600 feet thick, and whose manifestations are almost or quite exclu-

rOEMEE GLACIATIOX OF THE COAST NOETH OF VA2(C0UYEE ISLAND. 87

sively limited to its veiy termination. Here we ought, if we adopt the
ghxcier theorj', to expect to find large moraines, of which no trace has ever
been observed by any one, for the term '' glacial drift " means nothing, nnless
its real character is somewhere distinctly defined. Glacial drift may be
dropped a thousand miles away from any glacier, and scratched and polished
rocks can be, and are now, produced in abundance, not only by icebergs, but
by shore-ice, on the borders of the sea, as well as on those of great lakes, as
will be noticed further on.* The finding of marine fossils at various locali-
ties in the midst of the glaciated region is, as tlie writer conceives, fatal to
the glacier theory. Their presence is tlius accounted for by ]\Ir. Dawson :
" The general appearance of the deposits of this part of Vancouver Island,
resting, as they do, on planed and polished rocks perfect in every detail and
necessitating glacier action for their explanation, and 3-et consisting of water-
bedded and often current-driven materials mingled in places with sea-shells,
leads to the belief that they were formed along the retreating foot of a
glacier which had extended some distance beyond the margin of the land.
The withdrawal of the ice may have been caused or accompanied by sub-
sidence ; and some species of shells must have followed its front pretty
closely in its retreat. The somewhat irregularly terraced form of the de-
posit is probably due to action during emergence; and the general tendency
of many fixcts is to show that a slight sinking of the coast is at present in
progress or has lately occurred,"

Before entering into any further discussion of the glacial phenomena mani-
fested on Vancouver Island, and the true relations to the Northern Drift
epoch, something must be said in reference to the character of the coast
farther north between that island and Alaska, an extremely interesting
region on account of the deep indentations of the shore-line and the grand
mountain ranges whicli press upon it. This region has not, as yet, been
much explored, and the little we know of it, beyond tlie mere position
of the coast-line, is due to the reconnaissances of the Canada Geological
Survey. It is ([uite clear, however, that the range of lofty mountains border-
ing the coast has been occupied, in its higher portions at least, by extensive
glaciers ; and thiit these have found their way down the canons to the very
sea-level in places is also higlily probable. This is in entire harmony with
all that we have learned from the preceding pages in regard to tlie phe-
nomena of former glaciation in the high ranges adjacent to the Pacific. The

* See also page 11 of this volume.

88 GLACIAL AXD SUEFACE GEOLOGY OF THE PACIFIC COAST.

rano-es north of Vancouvei' Island were so situated, Avith reference to the
prevaiHng winds, as to condense by far the larger portion of the moisture
swept inland from over the ocean surface, — a condition of things perfectly in
accordance with what is now taking place along the Pacific Coast flirther
south, as an inspection of the Smithsonian rain-charts well illustrates. How
extensive the glaciers were in these comparatively high latitudes, on a lofty
range rising almost directly from the sea to a height of six or eight thousand
feet, can only be told by actual observation ; that they were of such gigantic
dimensions as to unite in one main stream of ice filling the Straits of Georgia,
moving southward and impinging against the base of the Olympian Range,
as maintained by Mr. Dawson, does not seem to have been j)roved, as has
been set forth in the preceding pages.

The investigations of Mr. James Richardson, of the Canada Geological
Surve\', who had an opportunity of examining many of the inlets north of
Vancouver Island, seem to have been carefully and conscientiously made.
His observations all go to prove the former existence of large glaciers in the
range along the portions of the coast seen by him on a trijj from Douglas
Channel to ^yrangel in Alaska. His remarks on this subject are instruc-
tive, although brief, and may be here quoted in full.* " Throughout the
whole of the inlet and channels which were examined, wherever the surface
of the rock is exposed, the ice-grooving and scratching is very conspicuous,
from mere scratches to channels often several feet in width, and from a few
inches to as much as two and three feet deep. Often they can be distinctly
seen with the naked eye from the surface of the water to upwards of 3,000
feet above it on the sides of the mountains. They run in more or less
parallel lines, and are not always horizontal, but deviate slightly up or down.
Sometimes the rocky surface resembles that of a field covered with narrow
ridges. Where two valleys meet, the upward deviation is always well marked
on the side of the smaller valley. A good example of this occurs at the
junction of the Kamino Valley with that of Gardner Channel, where on
the west side the hard gneissose rocks are scooped out in wide deep
grooves, occasionally undercut on the upper side, and rising from the level
of the water at angles of from eight to fifteen degrees. It would be
useless to enter into any great detail as to the direction of the grooves.
Generally, it conforms wilh that of ihc vallcijs,^ and the movement of the ice has

* Geological Siirvej' of Canada. Report of Progress for 1874 - 75, p. 81.
t Italicizc-J by the present writer.

FORMER GLACIATION XEAR BUTE INLET. 89

been from north, northwest, northeast, and east to the opposite point, modi-
fied by the sinuosities of the valleys through which it passed."*

Mr. Dawson continued his observations from Vancouver Island northward
through the Straits of Georgia for some distance along the coast ; but he
states that his opportunities for examining the remarkable fiords by which the
coast of the main-land is indented were but limited. The only one ascended
to its head was Bute Inlet, the mouth of which is about opposite the centre of
Vancouver Island, in latitude 50" 30'. Of this he speaks as follows : " This
chasm, forty miles in length, and running into the centre of the coast range,
is surrounded by mountains which, in some places, rise from its borders in
cliffs and rocky slopes to a height of from 6,000 to 8,000 feet. It must have
been one of the many tributaries of the great glacier of the Strait of Georgia,
and accordingly shows evidence of powerful ice-action. The islands about
its mouth are ruches moidonnees, polished and ground wherever the original
surface has been preserved. In Sutil Passage, near its entrance, grooving
appears to run about S. 30" ^y. A precipitous mountain on Valdez Island,
opposite Stuart Island, and directly blocking the mouth of the inlet, though
3,013 feet high, has been smoothed to its summit on the north side [the
Inlet has an almost exact north and south coarse] while rough towards the
south. The mountain-side, above Arran Passage, shows smooth and glisten-
ing surfaces, at least 2,000 feet above its face ; and in general all the moun-
tains surrounding the fiord present the appearance of having been heavily
glaciated, with the exception of from 1,000 to 2,000 feet of the highest
peaks. The high summits are rugged and pointed, and may either never
have been covered bj* glacier-ice, or owe their different appearance to more
prolonged w^eathering since its disappearance. In some places parallel flut-
ings high up on the mountain-sides evidence the action of the glacier; while
in others it is only attested by the general form of the slopes, or detected
under certain effects of light and shade. At the mouth of the Howathco
River, discharging into the head of Bute Inlet, striation shows a direction of
movement S. 22° E. ; but in every case the motion appears to have been
directly down the valley, and to have conformed to its changes in course."

The above citations seem to include all of importance that can at present
be stated in reference to the former glaciation of the Coast Mountains, oppo-

* This quotation from Jlr. Eichanlson's report has been given by Mr. Dawson in liis article on the Sniierlicial
Geology of British Columbia, previously referred to ; but all of it which relates to the conforming of the direction
of the ice-grooves with that of the valleys, and the deflection upward from the level of the water, which seems to
indicate iceberg or shore-ice action, has been omitted by him.

90 GLACIAL AiSTD SURFACE GEOLOGY OF THE PACIFIC COAST.

site Vancouver Island, on the main-land, and farther north towards Alaska.
There can be but little difference of opinion in regard to the general char-
acter of the former glaciation of the high range in question. The position
and direction of movement of the ice-masses was evidently governed by the
topography of the country, which at the time of the former greater extension
of the glaciers was in harmony with what it now is. There is a strong jjody
of evidence, as the writer thinks, to the effect that the ice-markings near
Victoria Avere the work of icebergs, and not of a gigantic glacier filling the
Straits of Georgia, as advocated by Mr. Dawson. So immense a development
of land-ice as Mr. Dawson's glacier would require seems not to be in har-
mony with what has been observed in regions farther south, or in the same
latitude to the east. The very uniform character of the manifestations of
the former presence of ice, over a length of more than a thousand miles, in
the ranges extending along the coast from Oregon to Southern California,
leads us to infer that so enormous and sudden an expansion of glacier-covered
surface as that demanded by an ice-mass fdling the Straits of Georgia is
something not to be accepted, unless thoronghlj' demonstrated by a series of
carefully conducted observations. Be this as it may, however, it must be
manifest to all that we have in this former extension of the glaciers, even
adopting Mr. Dawson's views, nothing which can be properly classed with
the Northern Drift, as will be more fully explained further on in this
volume.

Neither can the phenomena described by Mr. Dawson as occurring in the
interior of Briti.sh Columbia, east of the Coast Ranges, be regarded as indica-
tive of anything more than local glaciation on a large scale, even if his ob-
servations be accepted as entirely trustworthy. But as it appears that some
explorers and geologists see, with the greatest facility, glacial markings of all
kinds, and in perfection, where others of at least equal experienije are unable
to discover them at all, it may be deemed advisable to wait imtil further evi-
dence is obtained before concluding that the Fraser River Valley was the
scene of such an exceptionally large development of ice during the Glacial
epoch. The relations of the admitted conditions of glaciation in the Far
Northwest to those of the northeastern part of North America will, however,
be best discussed at a later period in this work. That Mr. Dawson himself
perceives the theoretical difficulties which present themselves in connection
with the facts which he professes to have ol)served, and that there is some
imcertainty in regard to these facts themselves, will, as the writer conceives,

FORMER GLACIATIONT OF BRITISH COLUMBIA. 91

be apparent from the following quotation from the summary of his remarks
on the glacial geology of the region in question*

" In attempting to cover with any general theory the traces of the last
great period of cold, generally known as the glacial period, in a district the
physical features of which are so well marked and so varied as those of that
under discussion, much difficulty is felt, owing to the great number of pos-
sible combinations of circumstance. The earliest recognized traces of the
period of cold are doubtless the markings on the surface of the plateau, or
high lands, in connection with it, which indicate the southward passage of
massive ice. These, by the observations above detailed, have now been found
in different parts of the interior jilateau, for a distance of over 300 miles, and
traced up, on Iron Mountain, to a height of 5,280 feet. Erratics and drift
material, with evidence of water action, occur to a like elevation. Ulieii
compared mth the ice-markings found in the lower vallei/s, and io those of the south-
eastern extremity of Vancouver Island, known to be due to glaciers, those of the
higher j/aiis of the interior plateau are less definite.^ The rocks are frequently
■well polished, with stria3 faintly marked, and varying several degrees in
direction. Ileavg grooving or fluting like that frequently observed inhere true glaciers
have been at ivork, is seldoni or never seen, the nearest approach to it being on
the summit of Tsa-whuz and Iron Mountains."

Dr. Dawson infers from all the facts observed by himself that it is " not
improbable " that a great confluent glacier did, at an early stage of glacial
time, cover the interior of the Province of British Columbia. This sheet, he
SAys, need not have been much more than 2,000 feet in thickness, and its
greatest efflux was doubtless by the valley and comparatively low country of
the Okonagan. If, however, this enormous glacier did discharge itself chiefly
through the valley of that river, the evidences of such outflow Avould, bej'ond
doubt, be of the most striking character. Enormous moraines would be
accumulated all through the region, and the surface far and wide would be
covered by erratics, and the piles of debris formed by the action of the water
resulting from the melting of the ice, on the detrital material previously
brouu;ht down from the reo-ion to the north. An examination of all that has
been published by trustworthy observers in regard to the surface geology of
that region indicates that nothing of this kind is to be found there. As ad-
mitted by Mr. Dawson, however, a considerable portion of this great ice sheet

* Geological Survey of Cauada. Report of Progress for 1S77 - 78, ji. 150.

t The author has taken tlie liberty of italicizing one or two passages in the qiiotation cited above.

92 GLACIAL AKD SUEFACE GEOLOGY OF THE PACIFIC COAST.

must have found its way out by the Valley of the Fraser. Here, again, the
evidences of such passage of a great glacier 300 miles long are singularly
defective. The few isolated boulders observed resting on the surface of the
local detritus, by Dr. Hector and others, are but a poor representation of
the former passage of a mass of ice larger than any now existing in the
world, unless in Greenland or at the South Pole. That these and other
similar difficulties did not fail to impress themselves on the mind of Mr.
Dawson, and that he was inclined to look with suspicion on his own " highly
probable " theory, is shown by the following extract from his report on the
region in question, which follows immediately after the suggestion of the
great confluent glacier, which he supposed to have covered so large a part of
the interior of British Columbia. He says: "It is well to remember, how-
ever, that the hypothesis of an Arctic current bearing heavy polar ice
through the Peace River gaps at the north, and thence southward down the
region of the plateau, would serve almost equalhj ivell to accouiit for its glaciationr
And he adds : " Any theory of the cause of these traces of the earlier gla-
ciation shall at present be held tentatively, and subject to the result of further
exploration."

In the preceding pages will be found, it is believed, all that it is necessary
to set forth in regard to the former glaciation of the western side of the
North American continent. With the facts which have been given, the
reader will be prepared to enter into the discussion of the probable relation
of the phenomena of past glaciation, as manifested on the Pacific Coast and
in the Rocky Mountains, to similar occurrences in other parts of the world.
Before advancing another step in the present inquiry, however, it will be
desirable to add to what has already been said about glacial phenomena
proper something in regard to one or two points of surface geology more
or less directly connected with the former occurrence of ice in the regions
which have been passed over in review in the preceding pages. And it will
also be proper to inquire whether there are any points in regard to the dis-
tribution of the superficial detrital material, in the non-glaciated portion of
region in question, which require special elucidation, as preparatory to the
discussion which it is proposed to enter upon in the succeeding chaptei's.

One of the first questions suggesting itself to the student of dynamical
geology, in connection with the phenomena of past glaciation which have been
described in the preceding pages, is this : Are there any marked, character-
istic features in the topography of the glaciated regions which distinguish

THE ]S"ON-GLACIAL ORIGIN" OF THE LAKES OF CALIFORNIA. 93

them from the non-glaciated? In the use of the phrase "characteristic
features," it is not intended to inchide such phenomena as have been fully
indicated above as being the legitimate work of the glacier, but to suggest
the possibility of other more obscure and uncertain results of ice-work which
may not reveal themselves at once to the observer, but which, on the other
hand, may be deciphered by a careftd study of the topographical features of
the regions in which ice has been shown to have done geological work in
former times. Among such results might be the occurrence of lakes, to which
reference has already been made, or peculiar forms of the cross-sections of
the valleys, or the terraced arrangement of the detrital materials; and in
reference to each of these topics some remarks will here be made, which
may be taken as supplementary to anything which may have been said on
the same subjects in previous pages.

In regard to the formation of certain lakes partly or wholly through the
agency of ice a few words may here be introduced. And first with reference
to what has more especially come under the writer's own observation, in
California and the Great Basin. All the important lakes of Cahfornia are
strictly of orographic origin ; that is to say, the water which fills them
occupies portions of depressions wdiich have been produced, not by eroding
agencies of any kind, but by the same crust movements which have given
rise to the mountains and valleys. We find lakes of this kind somewhat
abundant in California, and in all stages of progress toward entire desicca-
tion, as will be set forth in the next chapter. Most of these lakes belong to
the Great Basin system ; they are to the east of the main divide of the
Sierra Nevada, or entirely to the south of that chain. These will be noticed
more fully in connection with the phenomena of their gradual diminution, as
indicating one of the most general and important climatic changes of later
geological times.

The Coast Ranges of California enclose within their limits but very few
lakes, either large or small. South of San Francisco Bay, indeed, there is
hardly a single body of water worthy of being called a lake. This is naturally
to be expected, since the rocks are, almost everywhere, very pei-meable, the
precipitation moderate, or even small in the southern portion of the State,
and the evaporation large. Clear Lake offers a striking exception, and is the
only body of water of any importance within the Coast Eange system. It
is clearly of orographic origin, and it marks the temnination of the volcanic
formations on the north.

94 GLACIAL AXD SUEFACE GEOLOGY OF THE PACIFIC COAST.

The Great Valley of California was once a lake of magnificent dimensions,
but it now retains its lacustrine character only at its extreme southern end.
The orographic depression between the Sierra Nevada and the Coast Ranges
must once have been very deep, as well as of great length, since it has
been the recipient of all the detrital material swept down from both sides,
although in vastly larger quantity from the eastern, during a long period of
time. How deep these accumulations are is unknown ; a bore of a thousand
feet in depth at Stockton, about midway in the valley longitudinally, did not
reach its bottom.* A large part of the southern end of the San Joaquin
Valley is liable to be converted into a lake after a succession of unusually
rainy seasons. It is a swampy region overgrown with tules, having one
large but verj' shallow permanent body of water near its centre, and about
midway between the extreme southern end of the valley and the point where
the San Joaquin River debouches from the Sierra. This lake, called Tulare,
from the growth of tules (Scirpus palustris) which surrounds it, has an area
at ordinary tiuies of 600 or 700 square miles, and a depth of only forty feet ;
but its dimensions vary considerably from 3'ear to 3ear. The reason why
water stands in the southern poi-tion of the San Joaquin Valley is, that the
rivers coihing down the slope of the Sierra farther north have filled up the
depression more rapidly than those to the south, and thus formed a kind of
dam or barrier to the escape of the water, or to a perfect drainage of the
southern part of the valley. This larger supply of detrital material from the
more northern streams is due in part to the increased precipitation as we go
north on the slope of the Sierra, in part to the greater development of the
belt of schistose and more easily disintegrated rocks, and also, to consider-
able extent, no doubt, to the vastly increased supply of volcanic material
north of the San Joaquin River, which in places forms deposits of great
thickness aloni;; the foot-hills, and much of which was of a nature to be most
easily and rapidly eroded away.

The western slope of the Sierra Nevada is almost entirely destitute of
any lakes, except those very minute ones high up in the range, to be pres-
ently described. Bodies of water of considerable size once existed there,
although not in abundance ; but they have nearly all disappeared, having
become converted into sedge-grass meadows, or " flats," as they are usually
called. The slope of the range and its orographic simplicity are manifestly
unfavorable to the development of permanent lakes; the depressions which

* For some details as to the form of the cross-section of the Great Valley, see Auriferous Gravels, p. 2.

LAKES OF GLACIAL ORIGIN IN THE SIEEEA NEVADA. 95

originally existed in it, as shown by the form and position of the Tertiary
gravel deposits,* have long since been filled up. Lake Tahoe, however, as
already mentioned,! is a fine, and for California an exceptional, example of
an orographic lake of pure water and large dimensions. Situated in a de-
pression between two elevated ranges, on the very summit of the Sierra, it
is chiefly supplied by melting snow, and is kept fresh by the abundance of
this supply while its overflow is carried to a lower level, within the Great
Basin, there to disappear by evaporation in Pyramid and Winnemucca lakes.
The great depth which the depression occupied in part by Lake Tahoe must
originally have had, becomes evident when it is considered that, in spite of
the detrital material to it from the adjacent lofty ranges, it has still a depth
of considerably over a thousand feet.

No one of the lakes mentioned above could for a moment be supposed
to be of glacial origin; but there are others, mostly of minute size t and
very numerous, in the formation of some of which ice has undoubtedly had
a share. The greater part of the more important of these are so-called
" moraine-lakes," the origin of which is exceedingly simple. A stream of
water is dammed back by an accumulation of glacial debris, and a lake, of
greater or smaller size, is the x'esult. Such lakes ai'e usually shallow and not
permanent. The barrier may be broken away at any time ; and with the
universal shrinking of the glaciers which has taken place in later geological
times, the majority of the lakes thus formed have also disappeared.

There are other lakes which are usually even smaller than those of moraine
origin, and which occur high up in the mountains at the very heads of the
streamlets, and whose basins have unquestionably been formerly occupied by
glaciers. The basins of such lakes are always shallow, usually very much
so, and of solid I'ock, with little or no debris about them. As these small
bodies of water are quite at the heads of the streams, and at very high alti-
tudes, they must occupy positions where, during the glacial epoch, snow or
nev^ existed. T\\cy are, in most instances, higher than the ice could have
reached, and therefore liigher than the region where the glacier did most
of its work. Their extreme shallowness, however, rendei's the question how
they are kept filled with water one of more importance than tliat of their

* See Auriferous Gravels, passim.

t See ante, p. 57.

X These lakes are by far too small to be shown on onlinavy maps : more than fifty of them are indieatcd on the
Geological Survey "Map of a Portion of the Sierra Nevada, adjacent to the Yosemite Valley," which is on a scale
of two miles to an inch.

96 GLACIAL AND SUEFACE GEOLOGY OF THE PACIFIC COAST.

original foriuatioii. If tliey wei'e empty, their existence would hardly be
observed ; they might even escape notice altogether. The principal reason
why the water stands in these shallow basins is, that the rock, which is ex-
clusively granite, is impermeable : it holds up the water almost as well as
metal would do it. Again, the snpplj' of water to keep them filled is readily
forthcoming from the melting of the snow, which usually lies almost or quite
through the year at the base of the clift's by which these little pools of water
are surrounded. That there should have been inequalities existing in the
surface of the granite at the time the Glacial ejioch commenced, can certainly
not be a matter of surprise ; that the glacier, with the aid of the water pro-
duced by its melting, kept these depressions free from debris, or even, in
places, deepened them somewhat, is also a condition of things easily under-
stood. Tiie more difficult point seems to be, to find an answer to the ques-
tion why these hollows have not become filled up with the debris from the
adjacent slopes since tlie disappearance of the glaciers. This leads us to the
discussion of another interesting point which presses itself upon the attention
of the observer of the phenomena of past glaciation in the Sierra Nevada.

The jioint is this : the more one studies the localities formerly covered
with ice in the I'egion in question, the more one is impressed by the fact
that but a short period lias elapsed since this ice disappeared. The Glacial
epoch — for California, at least — is only just over. This is shown in many
ways, by none, however, more satisfactorily than by the astonishing perfec-
tion with which the glacial polish has been preserved over large areas for-
merly covered by ice. That the surface should retain the striations and polish
for a long- time, and in great perfection, where the rock was, immediately
after their production, covered deeply with debris and soil, is not so remark-
able. There are man}' localities in New England and in the vicinity of the
Great Lakes where the striaj are almost as fresh looking as if just made ; but
in all such cases the rock surface has only been recently stripped of its
detrital covering by the hand of man or otherwise. All through the Sierra,
on the other hand, where the granite is entirely bare of overlying debris,
and appears to have remained so ever since the ice left it, the polish is appar-
ently as perfect as it was when first made. The only theory by which these
facts can be explained is this, that but a short period of time has elapsed since
the work was done. It might perhaps be argued that the surface had
remained covered with debris until a recent period, and that this has only
lately been removed. This, however, is not a tenable supposition in view of

EECEXT DATE OF FORMER GLACIATIOX IX THE CORDILLERAS. 97

the fact that the moraines remain in such a perfect state of preservation. In
many places they look as fresh and iniimpaired in the completeness of the
details of their forms as do those of the present Alpine glaciers. These
remarks apply especially to the glaciated regions of the Sierra Nevada ; but
the freshness of the glacial markings in the Rocky Mountains is not much
less strikina: than on the western edge of the Cordilleras. The writer did
not see any surfaces of rock in the mountains about South Park or at the
head of the Arkansas River Avhich retained their polish as perfectly as those
at the head of the Tuolumne and elsewhere in the Sierra ; but the moraines
descending the eastern flanks of the Sawatch Range seem entirely unim-
paired, perhaps quite as much so as those previously described as occurring in
the vicinity of Mono Lake. The contrast is very striking between the fresh-
ness of the indications of the former presence of ice in the Cordilleras, and of
those which display themselves in Northeastern North America ; to the char-
acter of these latter attention will be more specially directed further on in
the present volume. It may be added here, however, that there is strong
reason to believe, as the writer has become convinced by repeated examina-
tions of both regions, that the period of the former more extended glaciation
of the Alps dates back further than that of the similar geological events in
the Cordilleras.

This simplicity of the phenomena of former glaciation in the Cordilleras
leads us also to infer that the time occupied by the Glacial epoch in that
jjortion of the continent must have been much shorter than that during
Avhicli the complicated series of events occurred which are referred to the
period of the Northern Drift in the Northeastern States and the region of
the Great Lakes. There are important general conclusions connected with
this aspect of the glacial question ; but their consideration may properly
be put oil" until a more advanced stage of the present discussion has been
reached.

Some words may be added in this connection in reference to a subject dis-
cussed at some length in the Auriferous Gravels, namely, the forms of the
valleys or canons in the Cordilleras, the especial question here to be consid-
ered being whether the former pi'esence of ice reveals itself in any easily
recognized manner in the figure of the cross-section of tlie valleys through
which it has passed. Observers frequently speak of the characteristic U-shape
of glacial valleys, as contrasted with the V-fonn of caiions resulting from
aqueous erosion. This is an error partly of misapprehension and partly of

98 GLACIAL AND SURFACE GEOLOGY OF THE PACIFIC COAST.

exaggeration.* The ftict is that the forms of valleys depend on a much
more complicated series of events than Avoiild be indicated by the use of the
simple phrases " aqueous " or " glacial." There is the original form to be
considered, in the first place. Something determines the passage of ice or
Avater along a certain line, or in a certain direction. This something is of an
orographic nature. Whoever has studied the structure of the earth's crust
as revealed in the many sections afforded by great mining operations, espe-
cially those made in the Carboniferous rocks on so gi-and a scale in Europe,
must have been impressed with the manner in which portions of the earth's
crust have been thrust up or down along vertical or nearly vertical planes.
Here is nothing of theory : the facts are of too much importance, from an
economical point of view, to be ignored. To assume, as some geologists do,
that great chains of mountains, made up as many are in large part of thor-
oughly squeezed, folded, and overturned rocks, had originally perfectly uni-
form surfiices, which have since been eroded by water or carved by ice into
their present forms, is to occupy a position emphatically at variance with the
great body of facts developed by geological investigations. It is only under
peculiar and exceptional circumstances that water has done most of the
work, as for instance in the case of the canons of the Colorado River and its
side valleys. As a general rule it is safe to assume that where U-shaped
valleys exist, the perpendicular walls have an orographic origin, and that
those of V-form have had that shape given to them by the debris piles which
have accumulated against their sides. The farther we descend the mountain
slope, the less the gi'ade, and consequently the less the carrying power of the
stream: hence, the valley which is U-shaped in the upper part of its course
acquires more and more of a V-form as it approaches the plain at the base
of the range in which it heads.

But glaciers have been and are now limited in their occurrence chiefly to
the higher portions of the mountains, hence their association in the mind with
the U-form of the valley. And this leads superficial observers to conclude
that the U-form is the work of the ice itself; Avhile the truth is, that the
material from which the glacier has been formed has simply been gathered
together in a pre-existing depression, all observations showing that great
mers de glace can only accumulate where the topographical conditions are

* Mr. J. F. Campbell exiiresses the same idea, but in a form much more limited and nearer the truth. He says:
"Every agent that wears rock leaves a dilferent mark. A glaciated valley has a rounded section — ' ; a stream
cuts a V or a Y-"

GENERAL KEMAEKS OX GLACIATIOX. 99

favorable. That the glacier, having been formed, carries away the detrital
material Avhich falls upon and delivers it at a distance from the place of its
origin, thus keeping the depression from becoming partly or entirel}^ filled
with debris, is a phenomenon which is of too simple a character to require
comment. However great the eroding power of the glacier may be after the
snow has become fully transformed into ice, there can be no question that it
must be very small as long as the material of which it is formed remains snow
or ntvt. Hence the utter inadequac}- of glaciers to carve out for themselves
the steeply walled cirques or amphitheatres in which they head, and which in
the Sierra Nevada often have almost exactlj'^ the form of a kettle, Avith the
rim broken away on one side.

The occurrence of terraces as indications of climatic change will come np
for discussion in the next chapter, such forms of detrital accumulations being
the especial result of diminution in the amount of water passing down the
streams, or standing in the lakes, along whose banks they are found. Ter-
races are not unfrequently regarded as being in some way connected with
former glaciation. It is true that where, owing to change of climate, glaciers
have disappeared, there is likely also to have been a diminution of water in
all the adjacent region ; but moraines are the results of the work of the
advancing ice, while terraces are evidences of the retreating of the water.
These two forms of detrital accumulations have, however, a certain re-
semblance to each other, which has often led unpractised observers into
mistakes.

Having thus in the preceding pages given a somewhat detailed description
of the character and extent of the manifestations of the former presence of
glaciers in the Cordilleras, the logical method of pursuing the subject would
seem to be to pass in review other portions of the earth's surface, in geograph-
ical order, and to furnish a similar statement for all those regions which exhibit
similar phenomena. It is evident, however, that such an undertaking would
require far more space than could be allowed in a volume like the present.
Besides, the facts are so well known and so easily accessible in a variety
of works, both general and special, that it is not necessary to go over the
ground again. All that needs to be done is to refer to and enlarge upon
such details of past and present glaciation, in certain regions, as may have a
special bearing on important points, and this will chiefly be done as these
points come up for discussion. A few very important districts will be de-
scribed with some fulness of detail ; while for most of the regions brought

100 GLACIAL AND SURFACE GEOLOGY OF THE PACIFIC COAST.

under review the author will be contented with giving references to the
sources from which full information may be obtained. Not, however, that it
is intended here to convey the impression that all has been ascertained that
is desirable in regard to the phenomena of the Glacial epoch. On the con-
trary, there is much yet to be learned, and there are many gaps in our knowl-
edge Avhich can only be filled by detailed and careful observations. This can
be done better than is at present possible after some definitely established
theory of the whole series of geological fiicts, of which former glaciation is
one, has become generally accepted. At present, as is evident from an
examination of the great mass of published materials, observers see, in many
instances, more of what they are inclined, from previously conceived theo-
retical notions, to expect, and less of what really does exist.

The facts which have come under the writer's own observation in North
America, and especially on the western side of the Continent, during many
3'ears of continued investigation, forming, as it were, the basis of the present
discussion, have properly been set forth with considerable detail. This has
been the more proper course, because it has not elsewhere been attempted
to be done ; nor could it have been, except by some one who had with his
own eyes seen a large portion of the whole region ; for the published state-
ments of some observers are so at variance with the truth, that only utter
confusion could result from an indiscriminate use of all that has found its
way into print on the subject of glaciers and ice-work as manifested in the
Far West.

Leaving, then, the glaciated regions of Northeastern America and of Europe
to be touched upon with more or less detail in a future chapter of this work,
we may now proceed to the consideration of certain phenomena of the
greatest possible interest as indicative of recent climatic change, and which
are manifested not only fxr and wide over the whole earth, but on an espe-
cially large scale, and with the greatest distinctness, in the region to which
our attention has been particularly directed in the preceding pages. We
refer to the diminution in the quantity of water running and standing on the
surface of the country ; to the drying-up which has been going on over a
large part of the earth during the later geological times, a phenomenon so
wide-spread and important in its manifestations as to demand a much more
careful study than it has hitherto received.

CHAPTER II.

THE DESICCATION OF LATER GEOLOGICAL TIMES.

Section I. — Introductory.

Climatic changes manifest themselves upon the earth's surface in a
variety of ways. The one essential cause underlying all tliat complex of
conditions to which the all-emhracing term " climate " is applied is, of
course, the solar heat. But the manifestations of the effects of this funda-
mental agency are powerfully influenced by many different causes, some of
which are liable to be profoundly modified by variations of geological con-
ditions. This subject will come up for more careful consideration at a later
period in this volume ; at present all that it is necessary to do is, to call
attention to the fact that a diminution of the water flowing or resting
motionless upon the surface of the earth — of the volume of rivers and of
the area of lakes, in short — is a phenomenon which must be admitted by all
to be indicative of a climatic change, the importance of which corresponds in
a measure to the amount of such diminution. That such a change is now
going on, and that it has been for a very considerable length of time, we
shall now proceed to set forth, leaving the causes and consequences of this
desiccation to be discussed in another chapter. It will become evident, on
examination, that while the evidences of climatic change presented by the
phenomena of extinct glaciation are extremely interesting, those of the dry-
ing-up are even more important, at least from a climatological j^oint of view,
for they can be traced over a much larger area of the earth's surface, and
have been continued during a longer period, than the glacial phenomena in
question. This desiccation is, moreover, especially interesting in that it is
an occurrence which is not only taking place at the present da}', but one
which is making itself felt in many ways as affecting the movements, the
prosperity, and even the life itself, of large masses of mankind.

It is indeed remarkable that so little attention has been paid to the facts
which will be brought forward in the following pages. Many of them have
been reported singly, but apparently without much weight being attached

102 THE DESICCATION OF LATER GEOLOGICAL TIMES.

to them, and certainly without any very definite idea of their bearing as
forming a part of a connected series of events. The almost or quite universal
tendency has been, and still is, to consider climate as something on the whole
quite fixed, and in its very nature invariable, or else to invoke the agency
of causes of a periodical nature, involving cycles of events, l^ut not any
permanent change. That both these theoretical aspects of climatic persist-
ency are quite contrary to the facts developed by geological investigation
will be made apparent, as the writer believes, in the following pages. But
without further introductory remarks, the essentially important facts will
now be laid before the reader.

Section II. — The Dn/ing-vp of the Lalccs of the Western Side of the North

American Continent.

It is not difficult to understand how it is that the decrease in dimensions
of a body of water like a lake is a phenomenon more striking in character
and more easily recognized than the gradual diminution of the volume of
water flowing down a river-channel. We are accustomed to see rivers vary-
ing their size in accordance with the progress of the seasons, and even shift-
ing their channels to a very considerable degree. The marks by which we
are able to recognize gradually occurring changes of volume are therefore
liable to be obliterated. And as long as a lake is only an expansion of a
river, while, in fact, it is in communication with the sea, its contents mov-
ing downwards with the river itself, only more slowly in consequence of its
greatly increased cross-section, so long any diminution of its volume which
may take place, unless it is very marked, will be likely to escape notice. But
let the lake be cut off" from its connection with the ocean, and become iso-
lated, by the increase of evaporation over precipitation, and the progressive
stages of a gradually lessening area will become very marked phenomena,
for the very causes which conspire to bring about this condition of things
are such as tend to preserve the records of their occurrence, which take the
form of ancient shore-lines, beaches, and terraces. A secular increase of
volume, in the case of both lakes and rivers, is natiirally more difficult to
make out than a diminution, because the rising waters conceal the work of
former ages. Forests, if submerged, gradually decay and leave few traces
behind. Tl)e works of man, on the other hand, are sometimes of a very
enduring character; but, of course, testimonials to change of water-level

STAXSBURY'S OBSERVATIONS AT GREAT SALT LAKE. 103

depending on human agencies can only be furnished under exceptionally
favorable circumstances, and for the very latest historical periods. The
great body of evidence going to show a diminution of the -water on the
earth is therefore furnished by the great closed basin regions of the world,
— those of Western North America and of Central Asia. Not that other
countries do not offer abundant testimony coiToborative of the facts S2)ecially
made evident in the regions mentioned. On the contrary, the body of lacts
which might be brought together, did space permit, is abundantly com-
prehensive in character to enable us to include the whole land surface
of the globe in our generalizations. We may first, however, speak of those
particular proofs of desiccation which are presented within the region of the
Cordilleras.

There is no body of water in the country which displays in a more marked
manner the characteristic indications of decrease of size than does Great
Salt Lake. Naturally, therefore, this was the first locality to attract the
attention of scientific explorers. So far as known to the writer, Captain
Stansbury was the first to call attention to the former much larger dimen-
sions of this body of water. Speaking of the low land near Promontory
Point, he says: "This extensive flat appears to have formed, atone time,
the northern portion of the lake, for it is now but slightly above its
present level. Upon the slope of a ridge connected witli this plain,
thirteen distinct successive benches, or water-marks, were counted, which
had evidently, at one time, been washed by the lake, and must have been
the result of its action continued for some time at each level. The high-
est of these is now about two hundred feet above the valley, which has
itself been left by the lake, owiiit/ probably to gnidual elevafion occasioned bij sub-
terraneous causes. If this supposition be correct, and all appearances conspire
to support it, there must have been here at some former period a vast inland
sea, extending for hundreds of miles; and the isolated mountains whicli now
tower from the flats, forming its western and southwestern shores, were
doubtless huge islands, similar to those which now rise fiom tlie diminished
waters of the lake." *

Here, as will be evident, the present greatly diminished area of Great Salt
Lake as compared with that of former times is distinctly recognized, Avhile the
causes and conditions of this remarkable chanse would seem, from the state-
ment italicized by the present writer, to have been entirely misunderstood,

* An Expedition to the Great Suit Lake of Utiili. By Howard Stansbury. Philadelphia, 1852, p. 105.

104 THE DESICCATION OF LATER GEOLOGICAL TIMES.

it being Captain Stansbury's idea, apparently, that the mountains surround-
ino- the hike had been elevated, and not that the lake itself had diminished,
so that its water surface now stands at a lower level than formerly.

The geologists of the various Pacific railroad surveying expeditions paid
little attention to the proofs of a gradual drying-up of the region under ex-
amination, and when they did observe them, they seem to have failed to
apprehend their true character. Thus Lieutenant Beckwith remarks, in
speaking of the terraces bordering Great Salt Lake : " They are elevated
from two or three hundred to six or eight hundred feet above the present
lake ; and if upon a thorough examination they prove to be ancient shores,
they will perhaps afford (being easily traced on the numerous mountains of
the Basin) the means of determining the character of the sea by which they
were formed, whether an internal one, subsequently drained off by the break-
ing or wearing away of the rim of the Basin, — of the existence of which at
any time, in the form of continuous elevated mountain chains, there seems
at present but little ground for believing, — or an arm of the main sea,
which, with the continent, has been elevated to its present position, and
drained by the successive stages indicated by the shores."*

Mr. W. P. Blake, who Avas attached to the party which explored the south-
ern portion of California, and whose geological investigations are contained
in the fifth volume of the Pacific Railroad Reports, published in 1856, noticed
the former existence of " an extensive fresh-water lake " in the northern part
of the Colorado Desert, by which term he designates the tract of country
lying between the Bernardino Range on the northeast and the San Jacinto
Mountains, and the connected ranges extending towaid the southwest along
the Pacific Coast. The area thus embraced within these lofty mountains is
about 120 miles in length, narrow at its northern extremity, where it is
called the Coahuila Valley, but widening out rapidly towards the south, and
meeting the Colorado River near Fort Yuma. This region is almost destitute
of water, the streams which find their way down the mountain slopes losing
themselves before reaching the valley. A considerable portion of this area is
depressed below the sea-level, as shown by the recent surveys for the South-
ern Pacific railroad, and there are abundant evidences, in the form of terraces,
ancient shore-lines, and deposits of calcareous matter at various points, that
the water of the Gulf of California once extended up nearly' to the head of
Coahuila Valley. The access of the sea having been cut ofl' by the accumu-

* Keport of Exploiatiuiis and Surveys, etc. (Pacific Kailroad Ec^iorts). Washiiigtou, 1S55, Vol. II. p. 97.

DEPRESSIONS BELOW THE SEA-LEVEL. 105

lations of sand and mud brought down by the Colorado as Mr. Blake sup-
posed, the region above the former mouth of that river became a closed
basin of salt-water, which afterwards gradually became brackish, and then
almost fresh, as shown by the character of the shells found at various points
around its margin. Finally', the entire body of water disappeared by evapo-
ration, and the region is now an arid desert, surrounded by detrital accu-
mulations which slope down, in the form of " washes," from the sides of the
enclosing mountains, and which for a distance of about forty miles, meas-
ured parallel with the trend of the valley, is depressed below the sea-level to
the amount of a hundred feet or more. This deepest portion, however, is
not that nearest the Colorado River, but is rather the upper end of the val-
ley, the line of the railroad survey sinking to the ocean level not far from
Indian Well, then continuing below that level for about forty miles, and
finally rising above it again some sixty miles before reaching Fort Yuma.*
In view of the facts developed by the recent railroad survey in reference to
the position of the depressed area in this desert region, it would appear that
the access of the Gulf must have been cut off by an actual rise of the land,
and not by the accumulation of debris brought down by the Colorado.

All that part of California which lies west of the Colorado and north of
the San Bernardino Range, as far as the eastern base of the Sierra Nevada,
embracing an area of over 30,000 square miles, is but little better than a
desert. It is traversed by broken ranges of mountains enclosing valleys,
in whose lowest portions are the visible remains of former lakes, now con-
verted into alkali-fiats, which become mud-flats during exceptionally wet
winters. The only one of these valleys known to be depressed below the
sea-level is that forming the sink of the Armagosa River, and which is known
as Death Valley, where there is an area of probably forty miles or more in
leno-th and ten or twelve in width which is from a hundred to two hundred
feet below the level of the sea. As for as known to the writer, this depres-
sion and the one previously mentioned, of the Coahuila Valley and its con-
tinuation, are the only areas in North America sunk below the sea-level, and
not filled with water, for the deepest of the depressions in the Great Basin
proper are several thousand feet in elevation at tlieir lowest points.

* The iilaii so often broached in California of iiumdating this depressed aiea by letting in the waters of the
Gulf, and thus redeeming from sterility this portion of the State of California, is one of which the absurdity would
become apparent to any one who would take the pains to make himself acquainted with the climatological pecu-
liarities of the region in question. It is quite on a par with the project of converting the Sahara into an inland
sea by digging a canal so as to give access to the waters of the Mediterranean.

106 THE DESICCATION OF LATER GEOLOGICAL TIMES.

During the progress of the California Geological Survey the evidences of
the diminution of the water in the lakes on the eastern slope of the Sierra
Nevada Avas a matter of frequent observation and comment. The terraces
around the shores of Mono Lake proving its former much greater depth and
larger area were described in the Geology of California, Vol. I.* (1865). The
highest terrace is there mentioned as being at an elevation of 680 feet above
the present level of the lake. The possible connection of Mono with Walker's
Lake, in past ages, is suggested, and the probable connection of these an-
cient greatly expanded lake-areas with the phenomena of extinct glaciation
insisted upon. The subject was brought up again in the Yosemite Guide-
Bookt(18G9) in the following words: "That there was formerly a much
greater precipitation of moisture on the eastern side of the Sierra than there
now is, seems proved by the former greater extension of the lakes on the
eastern slope. Mono Lake, for instance, is surrounded by terraces or benches,
which show that its surfiice once stood 600 feet higher than it now does, and
the same is true of Walker, Pyramid, and the other lakes on that side of the
Sien-a. No doubt at that time the now arid valleys of Nevada were beau-
tiful inland seas, which filled the spaces between the lofty parallel ridges by
which that State is traversed. Perhaps the slopes of those ridges were then
clothed with dense forests, offering a wonderful contrast to the present bar-
renness of the ranges, and the monotony and desolation of the alkaline
plains at their base."

The somewhat elaborate and very costly surveys and explorations carried
on, since the stoppage of the California State Geological Survey, in the region
of the Cordilleras, under authority of the United States, have developed a
large bod}^ of facts additional to, and corroborative of, what had been pre-
viously stated by the present writer in respect to the great diminution in
the area of the lakes of the Great Basin and of the Cordilleras in general.
Mr. G. K. Gilbert seems to have been the first person to go into any detailed
description of the phenomena in question, and his remarks will be found in
the volume of Geology publislied by the Wheeler Survej'.t

Mr. Gilbert adds his testimony to that previously accumulated in reference
to the absence of any proofs of a movement of the detrital materials on the

* Geology of California, Vol. I. p. 451.

t The Yosemite Guide-Book : A Description of the Yosemite Valley and the Adjacent Region of tlie Sierra
Nevada, and of the Big Trees of California. An official puhlieation of the Geological Survey.

t See Report upon Geographical and Geological Kxploratious and Surveys West of the One Hundredth lleriJiau,
ill charge of First Lieut. Geo. M. Wheeler, Vol. 111., Geology. Washington, 1875.

DESICCATIOX AS COXXECTED WITH THE CxLACIAL EPOCH. 107

surfixce in any one general direction. He remarks on this point as follows :
" The unrnflled repose of all snch unconsolidated beds in Nevada and ad-
jacent Utah is proof positive that no general glaciation has prevailed

We may conclude, without reservation, that the great ice-field of Eastern
North America had no counterpart in the same latitude at the West." After
describing some of the phenomena of former local glaciation about the crests
of the highest ranges in Nevada, his results and inferences agreeing in the
main with those of the present writer and of the geologists of the Fortieth
Parallel Survey, Mr. Gilbert goes on to speak of the diminution in area of
Great Salt Lake and of other bodies of water in the Great Basin. These
changes he describes in a chapter entitled The Glacial Epoch, remarking
that " for reasons which will appear in the sequel " he has " come to regard
as phenomena of the Glacial epoch a series of lakes, of which the beaches
and sediments are to be found at many points in the Great Basin." He then
proceeds to indicate, in considerable detail, the former outline of Great Salt
Lake at the period of its greatest extension, and to the ancient lake thus
bounded he gave the name of Bonneville, in honor of the earliest explorer who
brought back any authentic account of the Great Basin region, and of Great
Salt Lake in particular. The work of the Fortieth Parallel Survey having
superseded that of the Wheeler Survey in this region, it will not be neces-
sary to give any detailed account of Mr. Gilbert's observations, but only to
state the reasons Avhy this geologist described the phenomena in question as
belonging to the Glacial epoch. On this point he remarks as follows : " The
Bonneville epoch [meaning the time Avhen Salt Lake was much larger than
it now is] and the Glacial epoch were alike climatal episodes, and they
occurred in the same general division of geological time, namely, the division
of which modern time is the immediate sequel.* .... To account for the
origin of Bonneville Lake, we need to assume a climatal change that would
increase precipitation or diminish evaporation ; and both of these effects
would follow, in accordance with familiar meteorological laws, if the hu-
midity of the air were increased, or if the temperature were lowered. There
can be no doubt, then, that the great climatal revolution, which covered
our Northeastern States with ice, was competent to flood the dry basin of
Utah ; and that it actually did so is at least highly probable."

* jrr. Gilbert omits to mention the fact that this connection of the increased area of the Great Basin lakes
wicli the phenomena of past glaciation had been pointed out ten years earlier by the present writer, iu the Geology
of California, Vol. I.

108 THE DESICCATION OF LATEE GEOLOGICAL TIMES.

In point of fact, Mr. Gilbert, in the communication from which the above
extracts have been made, acids but little to what wa.^s previously known in
regard to the phenomena of desiccation in the Great Basin region. He con-
firms the previously observed fact of the former much greater size of Great
Salt Lake, and adopts the view maintained by the present writer, several
years before, in regard to the climatic character of the change, and its con-
nection with the Glacial epoch.

The Fortieth Parallel Survey, under the direction of Clarence King,
added much more to our knowledge of the facts connected with the
desiccation of Great Salt Lake, as Avell as of other portions of the re-
gions Avest of the Rocky Mountains.* Some of the theoretical views
advocated by the chief of that Survey, in his volume resuming the geo-
logical results of that great Avork, Avill be noticed further on : at present
we have only to do with those facts stated by him Avhich bear on the subject
before us. But, in the first place, it will be proper to quote what is stated,
as the net result of the investigations which this Survey, in regard to the
former glaciation of the regions, embraced within their field of inquiry. The
conclusions arrived at, and which are Avholly confirmatory of those of the Cali-
fornia Survey, are as follows : " Wherever in the Fortieth Parallel area a
considerable mountain mass reached a high altitude, especially Avhen placed
where the Pacific moisture-laden wind could bathe its heights, there are
ample evidences of former glacial action, but the type is that of the true

mountain glacier, AA'hich can always be traced to its local source On

the drier interior parts of the Cordilleras the ancient glaciers usually ex-
tended down to between 7,000 and 8,000 feet above the level of the sea. In
the case of the Cottonwood glacier of the Wahsatch, a decided exception, the
ice came down to an altitude of 5,000 feet."t

Bat Avhat Ave have to do Avith at present is, the evidence of recent diminu-
tion in the dimensions of the lakes of that part of the Great Basin and of the
Rocky Mountains embraced within the "Fortieth Parallel area "$ and ad-
jacent to it. In regard to this point the information given in Mr. King's

* See Fortieth Parallel Survey Report, Vol. I., Sj'stematic Geology, Section V., Quaternary, p. 459, et seq.

+ In the volume quoted above a diagi-am is given showing that portion of the surface adjacent to the fortietji
parallel which was formerly covered with ice. It forms but a very small fraction of tlie whole area embraced within
tlie field of the Survey.

t The "Fortieth Parallel area," or the belt of country embraced within the field of Mr. King's Survey, is
essentially all tliat portion of the Cordilleras which lies between the fortieth and forty-second parallels, and east
of the crest of the Sierra Nevada.

LAKES BOXXEVILLE AND LAHONTAN. 109

volume is full and definite. He distinguishes as especially important two
great " fresh- water lakes which occupied depressed portions of the interior
drainage, — lakes whose former limits are indicated by singularly well-pre-
served terrace-lines traced around the ancient shores." For the eastern one
of these former lakes Mr. Gilbert's name has been adopted by the Fortieth
Parallel Survey; the other is called by Mr. King Lake Lahontan.* The first
of these, Lalve Bonneville, extended from about the parallel of 42^ southward
to 37' 30', the meridian of 113" representing nearly the middle of the lake.
The extreme width was in latitude about 40° 21', where the east and west
extent was 180 miles; from north to south it had a stretch of about 300
miles. The present level of Great Salt Lake is nearly 4,250 feet above the
sea ; that of Lake Bonneville was about 940 feet higher, making the altitude
of its ancient water surface at the time of the greatest extension of the lake
not far from 5,200 feet. Below the upper shore-line is a series of successively
lower terraces indicating a gradual recession of the waters down to the pres-
ent level. The former outlet was to the north, into the valley of Snake
River, as first suggested by Mr. F. H. Bradley, and afterwards proved by
Messrs. Peale and Gannett of the Hayden Survey. There were some north
and south trending islands, the tops of the present mountain ranges of the
region, in the lake at the time of its greatest development ; but the area of
water in Lake Bonneville was on the whole much less irregular than that of
Lake Lahontan.

This last-named body of water, as defined bj' the explorations of the For-
tieth Parallel Survey, extended from 41"^ 30' southward to about the same
latitude as the southern waters of Lake Bonneville (37' 30'). The altitude
of the western lake was 4,388 feet, or about 800 feet lower than that of the
eastern one, and its area was also somewhat less. Lake Lahontan included
within its limits the present Walker's, Carson, Humboldt, Winnemucca, and
Pyramid lakes. The united area of these is about equal to half the present
lake surfixce of the basin of Bonneville. The outline of Lake Lahontan was
extremely irregular. Indeed, but little is known of its southern continuation,
and its limits in that direction could only be roughly made out.f It appears

* A map showing the position and area of these two ancient lakes, and of sundry other smaller ones, lying be-
tween these, is given in Mr. King's yoliime. The data for this map were in part derived from the work of the
Wheeler Survey.

t ChieHy from the barometric observations of Messrs. Gabb and Wilson, who were sent by the present writer to
explore the southwestern corner of N'evada in 1S67.

110 THE DESICCATION OF LATER GEOLOGICAL TIMES.

to the writer that it is very probable that the old lake surface had a
somewhat greater expansion to the south than is indicated on Mr. King's
diagram.

A very considerable part of the area of Lake Lahontan was occupied by
long peninsulas and islands, all of which were narrow, and had the regular
north-northeast and south-southwest trend of the ranges of this part of the
Great Basin. These islands rose above the surface of the water to an eleva-
tion of several thousand feet. It would be difficult to find anywhere upon
the surface of the earth, at the present time, a body of water having such
marked and interesting orographic features as those of the ancient Lake
Lahontan.

The exact position of the former outlet of this old lake seems not to have
been clearly made out. The writer agrees with Mr. King in believing that
the probabilities are that it was to the south. Unfortunately the region at
the southwestern corner of Nevada is one exceedingly difficult of exploration,
owing to its distance from civilization and the almost entire absence of water
over an area of many thousand square miles. These difficulties must be
taken into consideration, when it is noticed how little is accurately known
of the character of the countiy in this direction.

It must not be supposed, from the great attention paid by the geologists
of the Fortieth Parallel and the Wheeler Surveys to the two great ancient
lake regions mentioned, that these were isolated or abnormal features of the
Great Basin. The whole area lying between these two great bodies of water
was formerly occupied by lakes without number. The entire surface of the
country is intei'sected by nearly parallel mountain ranges, as an inspection
of any good map of the Cordilleras Avill show.* These often rise to the
height of several thousand feet above the adjacent valleys, which are usually
narrow in proportion to their length, and separated from each other by low
divides. These valleys are not always distinctly terraced ; but they have,
beyond doubt, been formerly occupied to a greater or less extent by bodies
of water. Some of these were isolated and of small dimensions ; others were
in connection with similar lakes or lake-like expansions of the rivers, perhaps
in some cases fonninsf bodies of water of verv complicated outline. It will
be a long time before explorations have been made in this region in suflfi-

* See map of California and Nevada, by the State Geological Survey of California ; and also the one entitled
"Cordilleras" in the Atlas accompanying the Fortieth Parallel Survey Report; this latter was drawn by Mr.
Freyhold, and it is by far the best general map of the western side of the United States yet issued.

THE TEEEACES OF BEITISH COLUMBIA. HI

cient detail to fix precisely the boundaries of all these ancient lake systems.
There can be no question, however, in regard to the main looint, namely,
that the Great Basui was once covered in large part by water, which formed
lakes of various dimensions but of complicated ontline, some of which were
equal in area to the Great Lakes of the eastern side of the continent. The
present aspect of the region in question is one of extreme aridity. The
existing lakes do not occupy one tenth part of the area formerly covered by
water. They are not bodies of fresh water ; but are saline and alkaline, as
must necessarily be the case in a region where evaporation is in excess of
precipitation, and where there is consequently no drainage of superfluous
water to the sea. No one can doubt that we have here evidences of an im-
portant climatic change occurring in later geological times, and in regard to
which several interesting questions suggest themselves, having reference to
the epoch of this change, its duration, and its relation to other manifestations
of a similar character, or at least leading to similar inferences in their appli-
cation to the topics up for discussion in the present volume. These ques-
tions, however, it will be best to defer until more facts have been brought
forwai'd from other portions of the Cordilleras, outside of the limits of the
Great Basin.

Next to the Great Basin proper, British Columbia may perhaps be re-
garded as offering the most remarkable indications of a change in climatic
conditions during the later geological periods. As already mentioned, the
streams throughout that part of the country embraced between the Rocky
Mountains and the Coast Ranges, north of the United States boundary line,
are bordered with numerous terraces, which remain in perfect preservation,
and prove beyond the possibility of doubt that the amount of water carried
off to the sea was vastly larger than it now is. The streams at the present
time are often almost a continuous succession of lake-like expansions ; but
this peculiar phase of fluviatile conditions as now exhibiting itself in British
Columbia is but a foint shadow of what it formerly was. We have at present
but little idea of the depth of the lakes in this region : there cannot be much
doubt, however, that some of them will be found to occupy depressions sunk
to considerable depth below the level of the surfaces of the rivers them-
selves. The valleys are manifestly orographic in character; and, that being
the case, portions of these are likely to be very deep, where so situated as
not to have become filled up with debris. Briti.sh Columbia exhibits, then,
at the pi'esent time, a transition stage between almost complete inumlation.

112 THE DESICCATION OF LATER GEOLOGICAL TIMES.

and entire desiccation such as is now presented in parts of the Great Basin.
Let the desiccation continue and the drainage to the sea be cut oft', then only
the deeper portions of the lalce-Ulve expansions of the rivers would remain ;
and, if the climatic conditions did not change, but still favored diminution of
the water, we should finally have the alkaline flats and salt lakes of the Great
Basin only remaining. The disajjpearance of the glaciers and the formation
of the terraces are the preliminary steps to such a condition.

The whole region of the Cordilleras has been from early times one highly
favorable, in its orographic conditions, to the development of lakes. A great
plateau-like area traversed by numerous ranges of mountains of course neces-
sitates a system of valleys of corresponding complexity. If we imagine the
corrugating forces to act always in one direction, and with uniform force,
these viilleys would not be likely to possess the necessary conditions for the
formation of extensive lake systems ; the depressions between the ranges
would be parallel to each other and would not vary much in depth in their
different portions. If the uplifting force died out equally in both directions
from the centre, the result would be a system of valleys draining both ways
from the highest point of the convex surface. If, on the other hand, the
whole uplifted mass sloped one way, the waters would necessarily flow toward
one side in preference. But if we suppose a force tending to pi'oduce a
corrugation of the surface, and acting transversely to that which has pre-
ceded it in point of time, it is evident that the result will be that the valleys
will be broken up into sections having difierent elevations above the sea-
level. We might suppose a secondary corrugation of this kind carried so far
as to almost obliterate the previous one, or at least to become the dominant
system ; but this seems to have been rarely if ever the case in nature, for a
certain persistence in the direction of the mountain-building forces seems to
have been maintained in all the great chains, even where these continued to
be developed during several successive geological periods. It has been stated
in the Auriferous Gravels* that there was proof that the Sierra Nevada has
undergone a certain amount of thrust, or been subjected to the pressure of
forces acting in a direction longitudinal to the trend of the range itself The
form of the valleys throughout the Great Basin indicates a similar condition
of things to have existed there in former geological ages, and there can be
little doubt that the depressions afterwards occupied by lakes owe their
oiigiii to this cause. Here, then, we have a good illustration of the differ-

* See Aurifurous Gravels, p. 49.

PEE-GLACIAL AND POST-CxLACIAL DESICCATION. 113

ence, as affecting drainage, between simply-acting orographic forces and
complex ones.*

Proofs of desiccation similar to those offered in the region of the Great
Basin are not wanting in any portion of the Cordilleras. But when we come
to examine in detail the surface geology of the country, we find that there
is some difficulty in drawing the line between the phenomena indicating
a diminution of the water surface as something now in progress, and those
which connect themselves with similar events belonging to a former geologi-
cal period. In other words, assuming for convenience the existence of a
distinctly marked Glacial period, we have to deal with a Pre-glacial as well
as a Post-glacial desiccation. All the facts to which reference has been made
above as being exhibited around the shores of Great Salt Lake and other
bodies of water in the Great Basin, we have no hesitation in referring to
the latest geological period, the Post-glacial ; and we even go further, and
unhesitatingly connect them with the present epoch, considering that the
drying-up is something now in progress. But, at the same time, a desicca-
tion which has been going on during the latest geological period, and is even
continuing at the present day, may have been begun considerably earlier ;
during the Pliocene epoch, or even before that. That this is the case
throughout the whole region of the Cordilleras, there is abundant evidence ;
and even a limited investigation of the geology of the North American
continent is sufficient to convince the observer that in seeking for proofs of
a diminution of water-area throughout the countrv, we have to do with a
phenomenon which belongs to the past as well as to the present. Some pre-
liminary observations will be necessary, however, before proceeding further
in this direction.

There are evidently two quite distinct phases in connection with the dimi-
nution of water area on the earth's surface ; one Ave may designate as oro-
graphic, the other as purely climatological. But it must be borne in mind
that every orographic change is liable to bring about climatic ones. This
point will come up for discussion further on ; at present it is only necessary
to remember that every new aspect of the earth's surface, whether area or
altitude of the land-masses be thereby affected, is attended by some new
features of wind or ocean currents, resulting in corresponding changes of
climate in the regions concerned. By the orographic phase of the desicca-
tion process we mean, then, to indicate a local change of condition, brought

* See ante, p. 13.

114 THE DESICCATION OF LATER GEOLOGICAL TIMES.

about primarily by crust movements, in contradistinction to such as might
result from more general causes, of a nature to affect the whole earth's sur-
face. For instance, we might conceive of such an elevation of a part or the
whole of the plateau of Central Africa as to cause the draining off of a large
portion of the many thousand square miles of area at present covered by w.ater
in that region. Such a change of altitude of a considerable mass of land would
imdoubtedly produce climatic changes to some extent ; but the diminution
in the lake area would not have had primarily a climatological cause. If, on
the other hand, we conceive the surface of the land to remain at its present
height and to be otherwise unchanged, but that, for some reason, the rainfall
in the tropical regions is diminished, then evaporation would gain on precipi-
tation and the area covered by water would diminish permanently, instead of
varying temporarily, as it would othervyise do, in harmony with the ordinary
fluctuations of the seasons.

Thus, then, if we find that there has been a great diminution in the area
covered by water on the western side of this continent during the later geo-
logical ages, we have to inquire how far this may have been due to an up-
heaval of the land, and how far to a purely climatological cause. This is by
no means an easy tasic, and it is tliis very fact which makes the kind of evi-
dence in regai'd to desiccation furnished by a region like that of the Great
Basin, or of Central Asia, as will be stated further on, of so much value, as
indicative of a change of climate independent of any orographic cause.
Bearing these considerations in inind, we may now proceed one step further
in the present investigation.

The combined investigations of all the geological surveys carried on west
of the Mississippi during the past twenty years make it evident that thci'e
have been great changes in the relief of the surface in that region during the
later geological periods. The present writer, however, is clearlj- of opinion,
after a careful review of the whole body of published fticts and a personal
inspection of a considerable portion of the area in question, that there has
been no essential alteration in the configuration or topography of the western
side of the continent since the Glacial epoch, — that is, since the time when
the crests of the highest ranges were, to some extent, covered with snow and
ice. Therefore, no part of the desiccation proved to have taken place since
that time can be due to orographic changes; the phenomenon must have
been a climatological one.

But during the Tertiary period vast areas of the region between the

THE TERTIARY LACUSTRINE AREAS OF THE CORDILLERAS. 115

Rocky Mountains and the Sierra Nevada were covered by fre.sli water, Ibrm-
in^- interior lakes, the exact dimensions of wliich have not yet been made
out, but ot which enough has become known to convey a vivid i(]ea of the
existence of a lacustrine development surpassing in magnitude anything now
existing on the earth's surface. For reasons which will be readily appre-
ciated, our studies of the relative areas covered by land and water at different
geological times must be limited to the occurrence of fresh water. We are
not quite advanced enough in this discussion to take uj) the question of the
changes of climate which have been continually going on during the geo-
logical times in consequence of the ever-increasing area of the land masses
and the diminution of the ocean sui'face. We know from the investigations
of the various surveys carried on in the Cordilleras, that the ocean has been
shut out from a large part of the region between the Eocky Mountains and
the Sierra Nevada for a long period, including certainly the whole of the
Tertiary epoch. Indeed, there are no Cretaceous rocks between the Wahsatch
Range and the crest of the Sierra, so that, in all probability, the sea has not
had access to any part of the belt between the 112th and 120th meridians
since the close of the Jurassic epoch. The extent of this belt over w'hich no
marine Cretaceous or Tertiary is found, in a north-south direction, is not as
yet exactly known. It appears to. extend, however, some distance to the
north of the boundary of California. We have, then, two enormous areas,
to one of which the sea has not had access since the close of the Jurassic
epoch, and to the other not since the end of the Cretaceous. The depres-
sions throughout these regions have, therefore, been so situated as to become
the recipients of detrital accumulations, either of subaerial origin or lacustrine
in chai'acter. The litholooical character of such materials would of course
vary considerably in different portions of the regions, according to the nature
of the conditions presented by the areas of depression and the surrounding
elevated ranges. Of the accumulated masses of material much would natu-
rally remain concealed by more recent deposits; but in many places a large
amount of erosion has so exposed the strata as to furnish excellent chances
for examining them. The large lacustrine basins are filled with deposits of
detrital material which in places have a combined thickness of several thou-
sand feet. Since the geological age of these formations could only be made
out by the aid of fossils, it is fortunate that in the region west of the Rocky
Mountains they are frequently abundantly supplied with these essential
guides to the geological relations of the various members of the scries. Of

116 THE DESICCATIOiSr OF LATEE GEOLOGICAL TIMES.

course these fossils are the remains of land or fresh-water animals and plants ;
and so great is their number and so various and extraordinary their char-
acter that their investigation, in the hands of Professor Marsh especially, has
furnished one of the most interesting and important contributions ever made
to the science of palseontology in any country. The study of the lithological
characters of the detrital materials can hardly fail to throw light on some of
the obscure points in the geological history of the region in question ; but as
yet the data are so imperfect that much must be left undecided.

All the principal divisions of the Tertiary epoch are represented in the
lacustrine accumulations of the Cordilleras ; but the older members occupy
much more space than the newer. The Eocene is represented chiefly in the
region lying between the Rocky Mountains and the Wahsatch Range. The
lowest member of this division of the Tertiary has, according to the investi-
gations of the Fortieth Parallel Survey, a maximum thickness of about 5,000
feet, consisting chiefly of rather coarse sandstones, with intercalated clayey
layers, the formation containing coarser materials near the ancient shores.
The fossils are mollusks in abundance, with a few fishes, and a wonderful
variety of other vertebrates. For this oldest of the Tertiary lakes of this
region Mr. King has proposed the name of Ute Lake. This body of water
filled the entire Green River basin for a distance of 150 miles nortli of the
fortieth parallel, and with an unknown extension to the south, but probably
for 200 miles farther in that direction, making its total length 350 miles or
more; its breadth must have reached 150 miles. During the period of the
existence of this body of water the Uinta Range foi'med an island in it, not
far removed at its western end from the main-land, and it Avas from this
quarter that the detrital material which was deposited in Ute Lake chiefly
came. After the accumulation of the beds (the Vermilion Creek series)
which form the base of the Eocene, within the liuiits of the depression in-
dicated above, Mr. King considers that a period of orographic disturbance
ensued, as the result of which an extensive area of the adjacent laiul on the
west was depressed, so that the breadth of the lake was doubled. As thus
enlarged it extended west to the 116th meridian. The rocks deposited over
this newly formed area of depression consist chiefly of fine-grained shales and
marls, containing many remains of fishes and fresh-water mollusks, besides a
few beds of lignite. Over these shales is a heavy deposit of ferruginous sand-
stone. The enlarged Ute Lake, called by Mr. King Gosiute Lake, diminished
in size in consequence of orographic disturbances combined probably with

MIOCENE LAKES IX THE CORDILLERAS. 117

climatic changes, and a new sheet of water resulted ; this was situated wholly
within the boundaries of the former Ute Lake, and it was succeeded hy still
another, each being characterized by its special Fauna. Of the precise limits
of these bodies of water little has as yet been made out ; hut the deposits
laid down beneath their surfaces contain an abundance of the most interest-
ing vertebrate remains, all considered by Professor Marsh to belong to the
Eocene. At the close of this period great orographic disturbances took
place over the Cordilleras, which resulted in the drainage or extinction of
the Eocene lakes, over whose surface no Miocene deposits are found, indicat-
ing an important palaeontological break at this period, and great changes in
the relative area of land and water throughout this portion of the country.

The orogi'aphic disturbances which marked the extinction of the Eocene
lakes, as indicated above, gave rise to new areas of water, into which detrital
materials were carried in abundance, forming deposits of great thickness and
extent, replete with interesting vertebrate remains The Miocene lacustrine
areas seem to have been two in number. One of these was of vast extent,
and was situated to the east of the Rocky Mountains. Here, on the de-
pressed and eroded surface of the underlying Cretaceous strata, over the
region now known as" the Plains," an immense sheet of water existed during
the Miocene period, including the White River lake-basin of Hayden, which
extended along the eastern slope of the range, from the parallel of 40^ far to
the northeast, beyond the limits of the United States into British Columbia.
The other lake was situated to the west of the llTth meridian and east of
the Cascade Range, in Central Oregon.

The deposits of the Miocene period in the Eastern basin have a thickness
of a thousand feet or more. On White River, where they have been eroded
into the most curious and fantastic forms, they give rise to that peculiar
type of country known as the Bad Lands (Mauvaises Terres). Here, also,
the strata are crowded with interesting fossils, all of which are the re-
mains of animals or plants living on land, or in and near fresh water,
and which have been described and figured by Leidy and Marsh. The
sediments of the Oregon Lake were of great thickness, equalling at least
4,000 feet, and being made up in large part of volcanic materials either
ejected from under the siu-face of the water or washed into it from the
surrounding volcanic summits. The abundant fossils foiuid in this region
also indicate the absence of the ocean, and the Miocene character of the
Fauna.

118 THE DESICCATION OF LATER GEOLOGICAL TIMES.

As we ascend in the geological series to higher groups, the difficulty of
separating tlie past from tlie present offers an obstacle to generalizing. It is
often impossible to say what is Pre-glacial and what Post-glacial. There has
been no sudden change in the Fauna wliich would afford a guide to the
classification of the more recent deposits. Some of the characteristic Pliocene
species seem to have lived on to quite a recent date ; and, although now
certainly extinct, it is not safe to say that some of them may not have be-
come so aluiost within the historical period. These points, however, are not
of vital consequence in connection with the present discussion. What is
particularly desired here is, proof of an area of water surface over the west-
ern portion of this continent diminishing with the progress of geological
time, wliich is not difficult to procure ; and proof also that tliis diminution
has been the result of climatological as well as orographic causes, this latter
branch of the inquiry being by no means as simple as the other.

It seems clear, however, that, so far as the region west of the Eocky
Mountains is concerned, if there was not much less water surface on the
whole during the later Tertiary times, there were, at least, no such great
lacustrine areas as existed during the Eocene and Miocene epochs. Lakes
Bonneville and Lahontan were large, Init not in comparison with Ute and
Gosiute lakes. So, too, the Pliocene lake-areas would not compare in size
with the bodies of water which preceded them in the same region. The
largest unbroken area of Pliocene lake surface west of the Rocky Mountains
seems to have been in the North Park region, occupying nearly the whole
of that valley, and extending along the North Platte up to latitude 41° 30' or
farther. Here, resting on the Azoic rocks, is a thickness of a thousand feet or
more of sandstones of varj'ing degrees of coarseness capped witli marls, the
whole of which Ibrmation is referred by Mr. King to the Pliocene, although
fossils seem to be wanting. Much is of course concealed by the later Post-
pliocene or Quaternary deposits.

Beyond, a very considerable extent of surface was no doubt occupied by
water during the Pliocene epoch ; but the deposits of that age being so
largely covered with later ones, tlie exact limitation of the Pliocene lake-
areas cannot possibly be indicated. The present Humboldt Valley seems to
have been one of these old basins, and this probably had ramifications extend-
ino; noi'th and south between the rano-es, so as to form an extensive water
surface of complicated outline like that of the former Lake Lahontan. Some
few fossil i-emains were found in this region, indicating the Pliocene age of

PLIOCENE LAKE EAST OF THE liOCKY MOUXTAIXS. 119

the formation, and the close relations of its Fauna to that of the Niobrara
Group east of the Rocky Mountains. It may be taken for granted that in
all the vallej's of the Great Basin, where tliere are proofs of the existence of
water during Quaternary or Post-glacial times, there must have been lakes
during the earlier Tertiary periods, although the conditions might not have
been favorable to the development of organic life in such localities, for it is
easily seen that large lake-areas in broad valleys would be much more favor-
ably situated for the growth of animals and plants than narrow and deep
valleys, into which coarse sediment was continually being carried by streams
descending the steep slopes of the adjacent ranges. As being in harmony
with the.se considerations, it cannot fail to be noticed how comparatively
poor in fossil remains are the deposits accumulated, largely by rapid river-
action, on the west slope of the Sierra Nevada, and how rich, on the other
hand, are those Inroad lake-basins of the earlier Tertiary period, farther east
in the Cordilleras.

The region east of the Rocky Mountains, included within the area of the
Plains, was undoubtedly extensively covered by water during the Pliocene
epoch. The precise limits of this immense lacustrine area cannot at present
be given. It is'known, however, that it bordered close upon the base of the
Rocky Mountains on the west, and extended into Kansas in the opposite
direction. North and south it stretched from Texas to fiir be\ond the United
States boundary-line. Of course over tlils vast area the thickness and char-
acter of tlie deposits are very variable. Near the elevated range on the
west the accumulated debris wouiil necessarily be greater in amount and
coarser in character. Fossils have been found in many localities, the re-
mains of the manmialia being of the most interesting character. This Plio-
cene lake-area was obliterated by the latest orographic disturbance which
gave their present form and altitude to the Rocky Mountain ranges. The
overlying Pliocene with all the underlying deposits have all been raised
bodily from the western edge, in a simple uplift without thrust or fold, so
that the net result, as respects drainnge, is quite unlike that which mani-
fested itself farther west. On the eastern side of the mountains there is an
extremely gradual and constantly diminishing slope down to the Mississippi
Valley, without any lakes whatever; while on the other side the original
corrugations in the older rocks have not been so entirely obliterated, by
filling with detrital materials, that there is not ample opportunity for the
accumulation of lar^e bodies of water, if only the climatic conditions were

120 THE DESICCATION OF LATER GEOLOGICAL TIMES.

favorable. Did, however, such depressions exist on the eastern side of the
Rocky Mountains, in the region of the Plains, it is very doubtful whether
they could be kept filled with water, since the precipitation is quite small.

That most elevated belt of the Rocky Mountains comprised within the so-
called Parks, beginning at the San Luis Parle, and extending to the Laramie
Plains, a region having an altitude of from 8,000 to 10,000 feet, has been
more or less occupied by water up to quite a recent period. North Park has
already been mentioned in this connection. San Luis Park, however, is
much the largest of the comparatively level areas designated by this term.
It is about a hundred miles in length, and from twenty to thirty in breadth.
Professor Stevenson * considers that this whole area " was at one time occu-
jjied by a great fresh-water lake covering an area of several thousand square
miles and fed by streams coming from the mountain glaciers." Mr. Endlich,t
in describing the same region, quotes Professor Stevenson's remarks, and
adds : " Essentially this statement agrees with my own observations." The
evidences of terraces seem to be rather obscure ; but the whole aspect of
the Park is that of an area covered in large part by water at no very distant
period. Mr. Endlich came to the conclusion that there were formerly two
large lakes here; one of 1,400, the other of 300 square miles of area. The
Rio Grande enters San Luis Park on the west side, and leaves it at the south
end, passing through a deep caiion of basaltic lava. Between the former
lakes, one of which occupied the northern and the other the southern end of
the Park, there is a ma.ss of volcanic rock, through which the river has cut a
deep caiion, and Mr. Endlich considers that the water of the two lakes was
drained off by the formation of fissures in the lava, which gave the river an
unobstructed exit. He also thinks that if the outlet thus produced were now
to be closed a new lake would be formed. This supposition must be based
on the idea that the Rio Grande drains such an extensive high mountain
area that its volume would be more than sufficient to overcome the evapora-
tion. This, however, appears to the writer somewhat doubtful, since the
streams at present coming into the northern end of the Park from down the
slopes of the lofty Sangre de Cristo and Sierra Blanca ranges do not succeed
in maintaining themselves against the evaporating tendencies, so as to reach
and join the Rio Grande. The upper part of the Park is, in short, an arid,
sandy region, but little better than a desert in its aspect.

* Wheelei-'s Reports, Vol. III., 1875, p. 462.
t Hayden's Report for 1875, p. 149.

DESICCATION OF THE ASIATIC CONTINENT. 121

Section III. — Desiccation of the Asiatic Continent, and of other Portions of

the World.

Having given an account, in the preceding section, of the phenomena of
desiccation in the region of the Cordilleras, it might seem but natural that
tlie eastern side of the North American Continent should next be taken up,
and considered from the same point of view. But when we come to exam-
ine the geological conditions exhibiting themselves in the region east of the
Mississippi, and in the vicinity of the Great Lakes, we find that we have to
deal with quite a different set of phenomena from those presented on the
western side of the continent, and that these introduce new complications
into the question of desiccation, rendering the understanding of the prob-
lems involved considerably more difficult than we have found to be the case
in the discussion of the decrease of the water-surface in the Cordilleras.
For this reason it seems best to defer the consideration of the geological
facts indicating desiccation in Eastern and Northeastern America until an-
other chapter, when they will be taken up in connection with a discussion
of some of the general principles involved in desiccation and glaciation.
For the present it will be more satisfactory to pursue our review of the phe-
nomena indicating decrease of precipitation in a region more closely allied
in character with that which forms the subject of the preceding section than
is the eastern side of our own continent.

The poi'tion of the earth's surface to which we now turn is the Asiatic
Continent ; and here we find ourselves in the j^resence of conditions ex-
tremely similar in character to those which have been described as mani-
festing themselves in the Cordilleras ; but on a grander scale, and also
vastly more important in their relations to the past history, if not to the
future welfare, of mankind. It will become evident, from the facts presented
in this section, that Asia has been the scene of great physical changes during
the most recent geological times ; that of these no inconsiderable portion
has taken place within the historic period ; and that — as there is good rea-
son to believe — the development and migrations of great nations have been
most powerfully influenced by these changes.

In the entire continental mass of Europe-Asia (Eurasia, as it is sometimes
and very conveniently called, the separation between the two divisions being
a purely artificial one) we have, in round numbers, twenty-one million

122 THE DESICCATION OF LATER GEOLOGICAL TIMES.

square miles of territory,* of which a little over seventeen millions belong to
Asia projjer, this being considerably larger than the combined area of North
and South America. Here, too, we find the largest existing area of land
Avithout drainage to the sea, forming a series of closed basins, of which the
entire area is probably not less than three milhon square miles. This closed-
basin area is, in most respects, closely analogous to our own Great Basin,
but is on a much larger scale. Like that, it is intersected by numerous
more or less independent chains of mountains, which enclose valleys, some-
times narrow and limited in length, and in other cases of vast dimensions.
Often each one of these valleys forms an independent basin ; then again
several are connected together into one drainage system. An exactly simi-
lar condition prevails in our own Great Basin, in the driest portion of which
each separate valley is usually closed at both ends, as is the case with so
many of the depressions between the ranges in Southern Nevada, — while
in other cases an area of considerable magnitude may be drained towards a
central depression by means of one or more transverse breaks, crossing sev-
eral ranges, as is the case with tiie valley of the Humboldt River, and the
various side-valleys more or less perfectly connected with it.

The Asiatic closed-basin region is centrally situated with respect to the
continental mass to wliich it belongs; while that of North America occupies
an area of an irregularly triangular shape, the southwestern corner of which
comes close to tlie Pacific, forming, in fact, a part of the Pacific slope, since
it is entirely surrounded by streams all of which empty into that ocean. —
for the branches of the Colorado and the Columbia head entirely to the east
of the Great Basin. In Asia, on the other hand, the drainage from the cen-
tral, elevated, and closed-basin region is radial, towards the Northern Oce.an,
the Indian Ocean, and the Pacific. And so vast is the continental mass that,
in spite of the immense size of the closed-basin area, the rivers descending
from its elevated borders, and flowing in each of the specified directions, are
of great size, so that a large number of them may be classed as rivers of the

* The estimates of the areas of the various continental land masses, given in tlie text-liool;s of geography, dilTer
from each other in the most surprising manner ; tliat of Asia being especially uncertain, the figures in regard to
that country varying from fourteen to eigliteen njillion square miles. The latest and most trustworthy author-
ity (Behni und Wagner, in Erganzungsheft, No. 62, ISSO, to Petermann's Jlittheilungen) gives the area of Asia at
44,572,250 square kilometers, equal, in round numbers, to 17,200,000 English square miles. By the same au-
thority Europe is given at 9,710,340 square kilometers, equal, in round numbers, to 3,750,000 English square miles.
The combined area of Eurasia is, therefore, in round numbers, 20,950,000 square miles. The area of America
(North and South) is put down by Belun and Wagner at 38,389,210 square kilometers, or 6,183,040 square kilo-
rm;ters less than that of Asia (2,387,000 English square miles).

THE REGION ABOUT THE MEDITEKEANEAN. 123

first magnitude. Only in the southwestern portion of the continent is there
an ahiiost entire absence of hirge streams ; as is easily understood when the
peculiar position of this region with reference to the system of the trade-
w'inds, and the proximity of the continental mass of Africa, are taken into
consideration. And this region may properly be the fii'st to be taken ujd for
investigation as to its possibly changed condition during historic times, and
during the period immediately preceding them.

From an examination of the facts it appears certain that the whole region
adjacent to the Mediteri'anean, both in Asia and Africa, — and, to a more
limited extent, in Europe, — has been, and still continues to be, the scene of
climatic changes, which have been more important than any taking place on
the earth's surface, in their effect on the well-being of the human race.
Here History goes back farthest with her records ; here remain authentic
monuments, of various kinds, testifying to facts which more or less directly
bear on the question before us, and justify us in believing that one of the
most prominent causes of social changes, and of the migration and decay
of races and peoples, in those countries, has been the constantly increasing
desiccation of the region in question — a region which embraces the area to
which the earliest real intellectual development of the human race was, so
far as history is concerned, almost exclusively confined.

It appears to be an established fact, that the region extending from the
western extremity of the Himalayas, through the valleys of the Euphrates
and Tigris, Arabia, Palestine, Greece, Egypt, and tlie whole extent of the
southern shore of the Mediterranean, and, in a more limited degree, the
countries on the northern shore of that sea, have been inhabited by a very
much denser population than that which at present occupies them ; and it
also follows, almost as a matter of course, that, with this diminution of their
population, these countries have lost almost all the importance which they
once had. It is quite unnecessary, and it would be here out of place, to
do anything more than recall the well-known fact that the various nations
included within the area bordering on the Mediterranean have, at various
times in the past, either consecutively, or with more or less overlapping of
rising with declining nations, ruled the portion of the world which had the
best claims to be called civilized — and this both by force of arms and by
force of superior intellect.

That no one of the nations inhabiting the region in question exercises, at
the pre.sent time, any dominating influence over the intellectual develop-

124 THE DESICCATION OF LATER GEOLOGICAL TIMES.

tnent of the world, is an admitted feet. But it is possible to go much far-
ther than this, and to say, that over extensive regions, where once the light
of civilization shone with its brightest effulgence, and both the arts and
the sciences had acquired a remarkable development, there now a scanty
nomad population, living from hand to mouth, without a single attribute
worthy of respect, just drags along a miserable existence, continually strug-
gling against the forces of nature, and palpably losing ground from century
to century. Let the reader, for instance, contrast the present condition of
Arabia with its former one, when it led the van of scientific inquiry, and
he will have a good illustration of the kind of change to which the writer
is here making reference.

That the cause of this immense going backward of the region to the
east of the Mediterranean is exclusively physical in character is not intended
to be asserted ; but that there is a physical cause which must have had a
most powerful effect in bringing about the condition of things here indicated
is beyond a doubt. It admits of demonstration that the countries in ques-
tion have become very materially drier than they were during the earlier
historic period ; and that, consequently, life is no longer possible there, ex-
cept under conditions which are not compatible with density of population
or with intellectual vigor.

It will not be possible, at the present time, to do m^re than give a few of
the salient facts which support the above assertion. It may, however, be
unhesitatingly declared that the evidence is abundant, and that it all points
in one direction. Here, however, as in the preceding section, a full discus-
sion cannot be entered upon. Only a few of the prominent facts can be
presented, and it must be reserved for another chapter to endeavor to make
out how far the phenomena of desiccation are to be ascribed to a purely
climatological cause, and how far to preceding orographic changes.

Decidedly the most striking event presenting itself to us, in the region
in question, as an evidence of desiccation within the historic period, is the
greatly diminished area of water-surface in the Aralo-Caspian basin, a
problem which has much occupied the attention of physical geographers
at various times, and especially within the past half-century, the literature
relating to this subject being already quite voluminous. Even to name all
the authorities who have written in regard to the changes which have taken
place in the physical geography of the region in question in historic and
prehistoric times, with reference especially to the channels of the rivers

THE AEALO-CASPIAN BASIN. 125

Aran and Sjr, and tlie varying form and area of the water-surface of which
Lake Aral and the Caspian Sea are the principal relics, would require more
space than can here be allowed. The main point in connection with the
subject at present before us is this : that the area covered by water in this
part of Asia Avas once vastly larger than it now is. It is also true that this
diminution has been effected — to a considerable extent at least — within
historic times, and there is little doubt that it is still going on.

Humboldt seems to have been the first physical geographer to fully
appreciate the interest attaching to the question of the former extension
of the two inland seas, the Aral and the Caspian, and tiioir connection with
the Polar Ocean. By his citations of the ancient authors who have written
on this subject, he has made it easy for more modern investigators to follow
the various contradictory opinions put on record by various writers, from
the time of Herodotus down to the beginning of the sixteenth centux'y.*
It was at Humboldt's request that the necessary hypsometrical determina-
tions were made, under the direction of the St. Petersburg Academy, to
determine the precise difference of level between the Caspian and the Black
Seas. The same eminent authority was also the first to clearly perceive
that violent catastrophes or orographic causes need not be called upon to
account for the desiccation of this region, but that the phenomenon was
purely a climatic one. He says : " The desiccation which is unquestionably
going on in the basin of the Aral Sea, and the changes which are to be
observed in that long file of lakes which mark the traces of a chainiel [sil-
lon] from the Aksakal Bai'bi to the pools [mares] of the Baraba steppe (the
remains of the Bitter Sea of the Chinese Annals), are in no way dependent
on any violent revolution in the order of nature. They are simply the
effects of the want of equilibrium between evaporation and the volume
of water brought in by affluent streams and by atmospheric precipitation.
They are quite of another character from the cataclysms of Fo-hi and Yao,
which are supposed to have happened thirty-five and twenty-four centuries
before the Christian era."t

A more recent investigator in the same field is Major Herbert Wood, of
the Royal Engineers, who devotes considerable space in his work entitled
"The Shores of Lake Aral,"t as also in an article communicated to the

* See Asie Centrale, Paris, 1S43 ; Vol. II. p. 156.
t 1. c, Vol. II. p. 142.

t London, 1876. See especially Chapter X., " The Aralo-Caspian Sea," and Chapter XI., "The Caspian of
History."

126 THE DESICCATION OF LATER GEOLOGICAL TIMES.

Journal of the Royal Geographical Society,* to the discussion of the physical
changes going on in the Aralo-Caspian Basin.

To sum up the results attained by these and other investigators, it may be
stated that there is no doubt of the former vastly greater extension of the
combined Aralo-Caspian Seas, and extremely little as to their former connec-
tion witli the Polar Ocean. While there has been much discussion, without
absolute unanimity of opinion having been attained, in regard to the shifting
channels of the rivers entering these seas, and their variations of volume at
different times during the historic period, it seems to be beyond dispute that
a gradual desiccation, extending over a vast area, has been, and still is, in
progress.

Dr. Neumayr, in a notice of Professor H. Schmidt's work on the Aralo-
Caspian depression,! gives the following statement as the result of his inves-
tigations of this subject. t "The solution of this enigma is offered by the
study of the Tertiary formations of Eastern Europe and Western Asia. As is
well known [bekanntlich], thex'e existed, in later Miocene times, an immense
slightly brackish inland sea, which included the basins of Hungary and
Vienna, Transylvania, Wallachia, Croatia, Sclavonia, the Black Sea, the
Pontus, the larger portion of the Grecian Archipelago, and the Aralo-Caspian
Basin. At a still eai'lier epoch the region thus embraced was an immense
gulf of the Northern Arctic Ocean, from which the basin in question became
gradually separated. The freshening of the arm of the sea thus cut off from
communication with the salt water became possible, as may be atHrmed with
almost certainty [ziemlicher Bestimmtheit], by means of an outlet in the
direction of the upper course of the Irtysch and Obi Rivers. This immense
brackish-water basin has been, ever since later Miocene times, in the condi-
tion of continuous decrease in size ; and the intercalation of the glacial
epoch had no effect, so far as has been yet made out, in raising its level.
The separation between the Black and the Aralo-Caspian Seas must have
taken place before the former became connected with the Mediterranean,
as is shown by the small amount of saline matter in the Caspian; and the
union of the Black and the Mediterranean Seas must be of very recent
date, since the detrital deposits on the borders of the Black Sea contain

* See Journal of the Royal Geographical Society, Vol. XLV. (18"5), p. 367, Art. XV., entitled " Notes on the
Lower Amii-darya, Syr-darya, and Lake Aral, in 1874." By Major Herbert Wood, E. E.
+ Prof. Dr. H. Schmidt, "Die Aralo-Kaspi Niederungund ihre Befunde." Leipzig, 1874.
t Verhaiidlungen der k. k. geol. Keichsanstalt, 1875. p. 31.

THE AEALO-CASPIAN BASIN. 127

a brackish-water ami not a marine Fauna. We therefore perceive that
the separation of the region of tlie Pontns from that of the Aralo-Caspian
Sea could only have been effected by evaporation of the water, or diminu-
tion in tlie volume of the afliluents."*

In regard to the positive diminution of the water-surface of Lake Aral
during the most recent historic times, the following quotation may be offered
from Humboldt's work, to which reference has alreaih' been made. He
says: "At the present time [aujourd'hui] Lake Aral, especially at its
northeastern end, is diminishing in size in an extraordinary manner. The
Bay of Sari-tchaghanak, for instance, extended, hardly eight years ago, to
the hill of Sariboulak, now twelve leagues distant from its present bank.'"t

In regard to the some point Major Wood remarks as follows : '• The
sand dunes and tracts of hard clny occurring on the low shores of Lake Aral
point to the conclusion that extensive areas of country, which are now dry
land, were formerly covered by the water-spread of the lake. It has been
remarked that the mouth of the Syr-darya has become, in recent years,
fordable ; and that the depth of water between the island of Tokraak-Atta
and the north shore of Lake Aral has been diminished. It is also an estab-
lished fact that a minaret, which graybeards of the Kirghiz state was for-
merly situated on the edge of the eastern shore, is now at some hours' walk
distant from it ; and finally, since 1848, when it was a marshy swamp. Gulf
Abougir, at the southwest corner of the lake, has been entirely dried up,
and its bed is now under cultivation. There is no doubt that the cause of
this continuous shrinking in the area of Lake Aral is, that the evaporation
from its surface is in excess of the supply received by it from the Amu and
the S3r." t

In describing the phenomena of the desiccation of the Aralo-Caspian Basin,
Humboldt gives no reason why evaporation should so steadily have been
getting the upper hands of precipitation. The object of this chapter being
simply to furnish evidence of the fact of a general desiccation, the di.><cu.*sion
of the causes of this extraordinary event is reserved for a succeeding chapter,
and the reader is now invited to pass on to the consideration of similar con-
ditions in an adjacent region.

The importance, from the jioint of view of the present investigation, of the last paragraph induces the writer
to repeat it in the original : "Wir sehen demnach, dass die Trennung des Pontisehen vom Aralo-Kaspischen
Gebiete lediglieh diirch Verdunstung des Wassers oder Abnahmc der ZuflUsse veranlasst sein konnte."

t 1. c., p. 271.

t Journal of the Royal Geographical Society, Vol. XLV. p. 403.

128 THE DESICCATION OF LATER GEOLOGICAL TIMES.

Closely adjacent to the Aralo-Caspian depression is the vast region known
to us by the name of Persia, — a country containing not less than 600,000
square miles of area, much the larger portion of which is a lofty table-land,
elevated from 3,000 to 4,000 feet above the sea-level. This table-land is
surrounded by a ring of mountain ranges, everywhere higher than the in-
terior, which forms a closed basin, or series of tliem, nearly the whole extent
of country thus enclosed being an absolute desert. As Mr. Blanford re-
marks : " Not only is there no constant stream flowing from the interior of
Persia, but no water-course communicates with the sea from the interior,
and every drop of rain which falls on the Persian plateau is evaporated
within its limits." * Of this vast region it can be said, with truth, that it is
so dry that its population is barely able to find the means of subsistence ;
that this population has, on account of the dryness, greatly diminished, and
is still diminishing in numbers ; and that, from time to time, the most fright-
ful famines sweep away hundreds of thousands of victims.

These facts are so well known that it will not be necessary to do more
than to give one or two extracts, from thoroughly reliable sources, as illus-
trations of what could be furnished, in the way of evidence, in almost un-
limited amount. The following is quoted from the official report of the
Anglo-Persian Boundary Commission : " At every halting-place [on the
road from Bushahr to Shiraz] crowds of famished, half-naked men and boys
(the women and children were nearly all dead) thronged around our camp,
too weak to beg, but hoping, yet hardly expecting, succour from the bounty

of the infidels On my return I took the unfrequented eastern road to

Shiraz. Even here my servants buried three corpses on one day's march of
thirty-five miles, during which we did not meet a living soul." t

The present population of Persia is unknown. It has been estimated at
from four to ten millions. Behm and Wagner jiut it at " about 7,000,000." :|:
I'he Boundary Commission estimate the loss of life by famine, — " actual
deaths from disease and starvation," — in 1870-71, " not to have exceeded
half a million ; though, from the disproportionate mortality of women and
children, the ultimate loss to the country will be far higher."

According to Dr. Bellew,§ the loss of life by famine in the province of

* Eastern Persia. An Account of the Journeys of the Eastern Boundary Commission. London, 1876. Vol.
II. p. 449.

f 1. c, Voh I. pp. 95-97.

* Die Bevolkerung der Erde, VI. Ergiinzungslieft, Peternianu's Mittheil. No. 62, 1880.
§ Quoted in Behm and Wagner, VI. p. 30.

PERSIA. 129

Chorassan, during the years 1870-72, was not less than 120,000 persons,
which would be about one in .seven of the entire population.

The reasons which have been assigned by various authors for the evident
desiccation of Persia will, like those having reference to the Aralo-Caspian
depression, come up for consideration farther on. At present, it will be
desirable to give only one more quotation, from a highly scientific authoritj',
that of W. T. Blanford, tlie geologist of the Anglo-Persian Boundary Com-
mission, and the present chief of the India Geological Survey : " From the
accounts given by ancient writers it appears highly probable that the popu-
lation of Persia Avas much greater, and the cidtivated land far more exten-
sive, 2,000 years ago, than at present ; and this may have been due to the
country being more fertile in con.sequence of the rainfall being greater.
Some alteration may be due to the extirpation of trees and bushes ; but this
alone will scarcely account for the change which has taken place. I cannot
but think it probable that a gradual change in the climate of Central Asia
generally has taken place from the time when the great plain north of Per-
sia was under water, when the Black, Caspian, and Aral Seas were united,
and when, as Loftus has shown, the plains of Mesopotamia were a part of the
Persian Gulf, tliis gradual drying up of the country being thus connected
with the elevation of the steppe-region of Central Asia, and of the northern
coasts of Persia. To this gradual reduction in the rainfall of modern times
is probably to be attributed the circumstance of the Oxus no longer reach-
ing the Caspian, and the diminished volume of that river; for I cannot but
suspect that the diversion of the Oxus from the Caspian to the Aral Sea in
the sixth, and again in the sixteenth century, was but the last in a series of
changes in a stream which once, in all probability, carried the surplus waters
of the Aral Sea to the Caspian. To the same cause is probably due the
gradual diminution of the Caspian and the Sea of Aral; and hence the dis-
appearance of the lakes which once. I believe, covered no small part of the

interior of Persia But for inland seas and lakes to have occupied the

interior of Persia, and for large deposits to have formed in them, it is evident
that the climate must have been mucli damper than at present. In recent
times the rainfall has been insufficient to supply water either to fill the
basins, or, as we have seen, to wash down the detritus which accumulates at
the foot of the hills."*

* See, Quarterly Journal Geological Society, London, Vol. XXIX. (1873), p. 493, an article entitled " Ou the
Nature and Probable Origin of the Superlicial Deposits in the Valleys and Deserts of Central Persia."

130 THE DESICCATION OF LATER GEOLOGICAL TIMES.

Evidence of similar character in regard to past and present desiccation
may be gathered in abundance for regions adjacent, on the east, to those to
which our attention has just been directed. The diminution of the lakes in
the closed-basin region of Northwestern India, Western Thibet, and Turkes-
tan, has been repeatedly noticed and described by scientific writers within
the past few years. For instance, Hermann von Schlagintweit, in an article
entitled "Investigation of the Salt Lakes in Western Thibet and Turkestan,"
says : " In all portions of High Asia, both south and north of the main water-
shed, there are numerous places where the former existence of mountain
lakes may be recognized In Thibet, throughout the entire longitudi-
nal depression between the chain of the Himalayas and the main water-shed
of the Karakorum, of the once numerous lakes but comparatively few are in

existence So extreme is the dryness in Western Thibet, that in the

case of nearly all the lakes still remaining, the cvajjoration exceeds the pres-
ent supply of water, so that the prevailing condition is at the present time
one of gradual diminution in the area covered by water."*

The evidence furnished by the Geological Survey of India is to the same
effect as that previously obtained by the Schlagintweit brothers. A portion
of this evidence is thus summed up in the official resume of the work of
that Survey : " All around these lakes and lake-plains [of the Central
Himalayas] there is clear evidence that the waters once stood at a much
higher level. This fact points to a continuance of the cause which once
gave rise to these lakes, — a progressive decrease of precipitation and in-
crease of evaporation, whereby the carrying power of the streams has
become more and more out of proportion to the rate of disintegration of
the rocks." t

The obsei'vations of Mr. Drew, the author of an elaborate work on Jummoo
and Kashmir, $ fully corroborate the previously entertained idea that the
latter valley was once occupied by a large lake. This writer says : " The
observations of neai'ly every traveller to Kashmir have tended to show that
the Vale was in late geological times completely occupied by a lake. The
traditions of the natives — traditions that can be historically traced as hav-
ing existed for ages — tend in the same direction The existence of a

* Proc. Bararmn Acad, of Sciences, C'l. II. Band XI. Abtheilung I.

t A Manual of the Geology of India, chiefly compiled from observations of the Geological Survey. By H. B.
Mcdlicott and W. T. Blanford. Calcutta, 1879. p. 672.

{The Jummoo and Kashmir Territories. A Geographical Account. By Frederic Drew, F. R. G. S. , F. G. S.
London, 1875.

THE THIAN-SCHAN AXD HIMALAYAN RANGES. 131

lake over tlie whole valley of Kashmir occurred at no remote time, speaking
by a geological standard ; but it was long enough ago to have preceded an}'
of the monuments of man that have yet been discovered." The area which
must have been covered by water " at no remote time " was about 2,000
square miles.

In continuing our observations of the phenomena of desiccation in an
easterly and northeasterly direction from the region just passed over in
review, we find ourselves confronted by facts of a similar character to, and
on quite as grand a scale as, those described in the preceding pages. Want
of space makes it impossible to do more than offer a few citations from the
works of the most eminent modern explorers of the arid regions of Central
Hit>;h Asia.

The mountains of the Thian-Schan, a great complex of ranges stretching
off to the northeast, in parallel alignment, from the so-called Pamir Plateau,
and forming the crumpled border of High Asia on its northwestern side,
have been recently explored, in considerable detail, by Sewerzoff, who thus
expresses himself, when speaking of the distribution of forests on the i-anges
in question : " Be this as it may, the ftxct that many forests which have been
destroyed are never replaced shows that these forests were developed at a
time when the climate of the Thian-Schan was moister than it now is; and
that it was once moister is proved by traces of former glaciers and lakes which
have now disappeared, as well as b}' the fact that Issyk-Kul (Lake Issyk),
which has no outlet, has materially decreased in size, as is proved by the posi-
tion of the sedimentary deposits which surround it, and reach an elevation
from 300 to 500 feet greater than that of the present surface of the lake."*

The author of '' The Indian Alps " f (Mrs. Mazuchelli) makes similar
remarks with regard to the portions of the Himalayas traversed by her
party. According to her, the pines in the higlier regions are all dying out,
and no young ones are growing up to supply the deficiency. No mention is
made of desiccation as a possible cause of this condition of things, in this
case, but it would seem that this must be the chief one. In many parts of
the High Sierra, in California, the writer has observed similar facts, indicat-
ing that the growth of trees, along the upper limits of arboreal vegetation,
is disappearing, never to be replaced. $

* Petermaim : Erganzungslieft, No. 43. 1875. p. 67.

+ The Indian Alps and How we crossed them. By a Lady Pioneer. London, 1876.

t See also, on this point, C. King's " Mountaineering in the Sierra Nevada." Boston, 1872. p. 252.

132 THE DESICCATION OF LATER GEOLOGICAL TIMES.

According to various trustworthy authorities, and especially Richthofen. —
whose great woi'k, entitled " China," is a treasure-house of information in
regard to that country and Central Asia in general, — a vast area, lying
between the Kuen-Luen on the south and the Thian-Schau and Altai ranges
on the north, has been covered by water until within comparatively recent
times. To quote Richthofen's words : " It is a well-established fact, that the
ocean, at the end of the Cretaceous period, filled the Han-Hai ; that stratified
deposits were formed in it, for which the material (sand and gravel) was furn-
ished by the rivers flowing down [fiom the adjacent mountains] ; that this
inland sea had a communication with the great ocean, up to an indetermi-
nate later period, through the Djungarian basin or depression [die Dsun-
garische Mulde]. The Han-Hai is an elongated depression, extending in a
west-southwest and east-northeast direction, the western portion of which,
where least elevated, near Lake Lop (Lob-Nor) is probably not more than GOO
meters above the sea-level, while the deepest depression of the eastern part
is 607 meters in elevation. This now diied-up inland sea, the Han-Hai of
the Chinese, had — placing its western limit in Ion. 75° 30', and its eastern
in Ion. 114° 30' — a length of over 1,800 geographical miles, which nearly
equals that of the Mediterranean.

" Communication having been cut off between the Han-Hai and the ocean,
there was left a great closed basin or inland sea [grosses Binnenmeer], which
by gradual evaporation became divided into several smaller basins, and these
again gradually diminished in size, some having become quite dry, while
others have not yet entirely disappeared, but form salt lakes. The retreat
[Riickzug] of this sea may possibly be connected with the period of volcanic
activity which has left its traces in the Thian-Schan and in Eastern Mongolia.
But nothing is definitely known in regard to the precise time of the forma-
tion of this inland sea or its development." *

Richthofen does not, as will be observed, profess to go into any details as
to the character and origin of the orographic or climatic phenomena which
accompanied, and presumably brought about, this great change in the physi-
cal geogi'aphy of so extensive an area. He cannot, however, avoid noticing
that such a succession of events as he describes indicates the prevalence
of a dry climate during the later geological periods, for he says ; " It may
be stated as a certainly ascertained fact, that in Central Asia a dry climate

• China, Vol I. p. 108.

EAST TURKESTAN. ' 133

has prevailed for a long time — as far back as when the Han-Hai was in
communication with the great ocean."*

Farther on reference will be again made to some of the points to the con-
sideration of which the desiccation of the Han-Hai naturally leads us. At
present we need only allude to the fact tliat Richthofen evidently considers
it as proved that a considerable portion of the diminution of the water-
surface of this great inland sea has been accomplished during the historical
period, for he says: "The Chine.se historical records prove that 4,000 years
ago Lob-Nor was an extensive inland sea [ausgedehnter See], and Avas prop-
erly called ' Si-Hai ' or Western Lake or Sea." t

Colonel Prjewalsky, the eminent and indefatigable explorer of Central
Asia, shows t that Lob-Nor was, at no very remote period, much larger than
it now is, and he also states that it is said by the natives to have diminished
considerably within the past thirty years. He adds : " Moreover, the fact
of a drying-up [Austrocknen] of the lakes is one which is observed all over
Central Asia."

Sir T. D. Forsyth, in a portion of his work on East Turkestan § compiled
from Dr. Stoliczka's notes, and relating to the geological structure of the
mountain ranges between the Tschang-Tschemmo valley and Schahidula on
the borders of Kaschgar, thus speaks of the detrital deposits in the valleys
of that region : " The melting snow carries large quantities of gravel into the
valleys, everywhere forming high benches along the water-courses. During
a past epoch, perhaps the diluvial, this process must have taken place on a
much larger scale than at present. Not only were the lakes much more
extensive, but valleys like the Tschang-Tschemmo and the Tangste were
from time to time blocked up by land-slips or glaciers, so that gravel and
clay deposits were accumulated, sometinies to a thickness of several hundred
feet. Near Aktagh are similar deposits of stratified clay, about 160 feet
in thickness, which cover an area of more than a hundred square miles.
There can be little doubt that, at the time when these large areas of water
existed, the climate of that now cold and dry region was milder and moister
than it now is, and also more favorable to animal and vegetable life. Evi-

* Cliina, Vol. I. p. 110. + 1. c, p. r25.

t Ecise an deii Lob-Nor, 1876-77. In Erganznngsheft to Petermann's Mittheilnngen, No. 53, p. 21.

§ In Erganzungsheft to Peterraanu's Mittheilnngen, No. 52, entitled Cst-Turkestan und das Pamir- Plateau,
hearbeitet nach dem offiziellen " Report of a Mission to Yarkund in 1873, under command of Sir T. D. Forsyth,
K. C. S. I., C. B., Bengal Civil Service." Mr. Forsyth's mission was accomp.anied by Dr. Stoliczka, as geologist,
and it is from his note.s that the above-quoted remarks are compiled.

134 THE DESICCATIOX OF LATER GEOLOGICAL TIMES.

dence of the correctness of this view is to be found in the occurrence of
sub-fossil Succinece, Helices, and Piipce in the clay deposits of Lake Pangkong,
while a land moUusk could, at the present time, hardly exist in that region
at all."

That a large part of Siberia has been covered by water up to within quite
recent times seems well made out from the accounts given by various geo-
graphical explorers within recent years. To cite only one at the present
time, Cotta says, in his de.scription of the country between the Ural and the
Altai: ''The almost horizontal diluvial covering which, without interrup-
tion, spreads itself over so enormous an area, that, even when the roads are
in good condition, it requires nine days and nights of rapid travelling to get
across it, has evidently, at a very recent geological period, been covered by
water. We are taught by this fact that Europe, closed in by the Ural, was at
that time entirely separated from High Asia, whose northwestern coasts rose
precipitoasly [aufragten] in the Altai, the mountains of Turkestan, and the
Caucasus. This water, which formed a division between the two continental
masses, was evidently not a great lake, but a broad arm of the sea, which,
beginning at the Arctic Ocean with but moderate average depth, was con-
nected with the Mediterranean through the Black Sea, and perhaps even with
the Red Sea, across the Isthmus of Suez." *

We have thus shown that High Asia and the countries adjacent to it on the
north and northwest have been, within the later geological epochs, the scene
of great physical changes, and that the diminution of the water-surface
through every portion of this vast area has attracted, in a marked degree,
the attention of recent scientific travellers. Without stopping, at the present
time, to discuss the statements presented, with reference to the real nature
of the phenomenon and its causes, it will be sufficient to call attention to the
fact, which cannot fail to have impressed itself on the mind of the reader,
that we have to do with an event — or, rather, a series of events — of the
utmost importance, if only for the immense size of the area involved in these
changes. The analogy between the phenomena presented in High Asia and
on its borders and those exhibited in the preceding section, with reference
to our own Cordillera region, is most marked, in so far as the existence of a
condition of desiccation, during present and past times, is concerned.

Before entering, however, on the propo.sed general discussion of the sub-
ject before us, it will be desirable to present facts of a similar nature to those

* Der Altai. Sein geologischer Bau, und seine Erzlagerstatteii. Lei]izig, 1S71.

INFLUENCE OF GEOLOGICAL CHANGES ON xMAN. 135

already laid before the reader, in reference to other coimtries. In pursuance
of this plan, we may next proceed to consider the region adjacent to the
Mediterranean, and especially that which borders this great inland sea on
the east and south. And we have to do, in this division of our investigation,
with a territory still more interesting, in its connection with the world's
history, than that to which our attention has been previously directed.
HiiJ-h Asia is looked upon by many as the cradle of the human race ; and it
is there that recent geological changes might be supposed to have connected
themselves most intimately with the history of the intellectual development
of mankind. And it is indeed possible that here we might have the most
interesting co-ordination of geological and historical events, if only the rec-
ords of the latter were not so deficient. The migrations of nations from the
heart of Asia toward the West are involved in obscurity ; and, in fact, all
that relates to the earliest history of mankind, throughout the world, is
almost an entire blank. That, however, the human race has been the wit-
ness of great geological changes can no longer be doubted ; but beyond a
few of the simplest implements used by man during long ages of his earliest
stage of development w'e have nothing to throw light on his social condition ;
and in regard to his migrations, through the long lapse of prehistoric
acres, we are still more in the dark. That such migrations did take place,
however, and on an extensive scale, seems indicated by facts which, although
fragmentary and imperfect, are clearlv of importance. If such has been the
case, then it is reasonable to presume that these wanderings of the prehis-
toric peoples were largely originated and directed by pln'sical causes. In
other words, the movements of the human race have been, and especially in
the earlier stages of its existence, from regions presenting less favorable
conditions towards those more highly favored in this respect.*

There can be no doubt that if we had an exact account of all that has
transpired on the borders of High Asia since the human i-ace began its exist-
ence in those regions, it would be equivalent to having a Hood of light
thrown upon what is now almost totally in obscurity, namely, the intel-
lectual development of man as affected by external physical conditions.
At present the countries adjacent to the Mediterranean present the most
favorable field for investigations of this kind, because here the historical
records are most complete. Not only are they the most complete, but they

* "The progress of human generations is shaped by the physical circumstances in which they live." J. W.
Draper, in "Thoughts on tlie Future Civil Policy of America." New York, 1865, p. 66.

136 THE DESICCATION OF LATER GEOLOGICAL TIMES.

go forthest back in point of .absolute time;* and when written records begin
to fail, architectural monuments, to some extent, supply the deficiency. So
extensive is the subject at present before us, that it is not possible to do more
than throw out a few hints as to conclusions reached, not without consider-
able examination of authorities on the part of the present writer ; so that, if
the body of evidence seems small, in comparison with the nuignitude of the
conclusions drawn, it is rather from want of space in which to dilate, than
from defect of material.

That most of that which we recognize as forming the basis of our intel-
lectual culture, science, art, literature, and religion has come to us from
countries bordering on the Mediterranean, no one will deny. How far, ex-
actly, Egyptian, Greek, and Arabian authorities have been dependent on and
drawn from each other will perhaps never be accurately known ; nor is it
material that it should be, from the point of view of the present inquiry. We
know that, either successively or by turns, these nations at the east end of the
Mediterranean shone with a brilliant light on what to us seems to have been
the outer darkness of the rest of the world. We know that from the eastern
end of that great inland sea light, perhaps with sundry vibi-ations back and
forth, reached the central portion, and later the western end. Egypt,
Greece, Asia Minor, Arabia, Italy, the southern shore of the Mediterranean
west of Italy, and Spain, have each, in turn, ruled the world, either by intel-
lect or by force, or more often by the inevitable combination of the two.
That no one of these countries stands in any such relation to the rest of the
world, at the present time, will be readily admitted ; and more than this
may be affirmed with truth. As a rule, these nations have reached a stage
of decadence from which they can never rise to occupy again the position
which they have lost. The Egyptian fellah and the Arabian bedouin know
nothing of the glorious history of their predecessors on the soil they now
occupy, and from whom they are lineally descended. Modern civilization,
the direct outcome of that which their ancestors originated and handed over
to the comparatively barbaric races of the North and West, has gone utterly
beyond their ken, and is something to which they can never find their way
again.

That the statement here made would be found to be strictly true in all its

* Tliere may be an exception to this in the case of the historical records of the Chinese people; but the lan-
guage, style of thought, and general development of that nation are so foreign to our own, and have had so little
influence on us, that — for the present at least — that country can hardly be taken into consideration in connec-
tion with an inquiry of the kind suggested above.

DECAY OF MKDITERKANEAN NATIONS. 137

details, if examined with a critical eye, is not intended to be maintained.
The countries on the north side of the Mediterranean, for instance, although
no longer able to dominate the civilized world, are not without some partici-
pation in its intellectual progress. Italy and Spain have kept pace to a
considerable extent with modei-n civilization, neither of these countries
exhibitino' that stage of decadence which Greece does ; while the latter coun-
try is far in advance of the region to the south and east.

The reasons for the mighty changes which have taken place in successive
ages among the nations which have had to do with the intellectual develop-
ment of the world and the spread of civilization are usually sought for in
something connected with an inherent property of decay belonging to the
various races, or to the human race in general — something not dependent
on the physical conditions by which the races in question have come to be
surrounded as the ages rolled by. When, however, we observe, that not
only in those regions of High Asia from which migrations are usually sup-
posed to have begun, but all through the countries bordering on the Medi-
terranean, we are everywhere confronted by evidences of a change of climate,
and the entering in of conditions evidently unfavorable to mental vigor and
national welfare, we are justified, as the writer believes, in asking the ques-
tions, Is it not in consequence of these changes in the physical conditions
that the races themselves have changed, and has not the climate of a con-
siderable portion of the I'egion in question become such that we can saj
Avith truth that it is incompatible with a maintenance of those modes and
habits of life which accompany high civilization ?

The evidences of a diminution of the amount of water standing and flow-
ing upon the surface in the various countries bordering on the Mediterra-
nean, especially those on the east and south, are most ample and of varied
character. But it is especially the conformation of the surface which leads
us to infer a most decided desiccation during the latest geological periods.
There are everywhere not only depressions which have all the appearance
of once having been occupied by lakes, as evidenced by the terrace-marks
and other indications of the former presence of water, but there are also
numerous long, continuous valleys, — canons, as they would be called in
California, — which show by their form and position that they can only have
been formed by running streams ; and these valleys are now, almost without
exception, either entirely dry the whole year round, or onlj' occupied by
water here and there at very irregular intervals of time.

138 THE DESICCATION OF LATER GEOLOGICAL TIMES.

As has been done in the preceding pages for Central Asia, so here only a
few references can be made to the writings of scientific travellers who have
made mention of fiicts bearing on the question before us ; and, in preference,
the most recent authorities will usually be cited.

Arabia may be first mentioned, as a striking instance of a country greatly
dimini.shed in population, and utterly cast down from the high position it
once held ; while, at the same time, it presents ample evidences of a great
climatic change during the most recent periods.

Vivien de Saint-Martin says of this country : " There can be no doubt
that, since the days of antiquity [les temps antiques] the climate and the
physical conditions of a part of Arabia have undergone very great changes,
in consequence of the disappearance of the forests on the western coast
mountains. M. Fulgence Fresnel, an excellent observer, wrote in 1837 as
follows : ' It is a well established fact that the volume of flowing water is
constantly diminishing [diminue sans cesse], and has not ceased to diminish,
in a country celebrated for its dryness even in the days of Abraham, in a
country where Ishraael owed to a miraculous inteqiosition the existence of
the spring which saved his life. People still remember that, in the valley
of Sapra, there was a time when there was running water in the Bouraikah ;
but that stream has now dried np, and Djar, indicated on Niebuhr's map,
belongs to ancient geography.' " *

Noel des Vergers, in his "Description de I'Arabie," says: "Unfortunately
the return of the rainy season, which hardly suffices for a few torrents, and is
not enough to keep a single stream alive during the whole year, is liable to
distressing interruptions. An absolute drought sometimes lasts for two or
three years continuously over a portion of some province, rendering the
whole region barren, and producing famine and all the accompanying
diseases." t

Lady Anne Blunt says : " The whole of the peninsula, with the excep-
tion perhaps of Yemen and certain districts of Hadramaut within the influ-
ence of the monsoon winds, is a rainless, Avaterless region, in every sense
of the word a desert. The soil is a jioor one, mainly of gravel or of sand,
and, except in a few favored spots, unsuited for cultivation; indeed, no cul-
tivation is possible at all in Nejd, except with the help of irrigation, and,
as there is no water above ground, of irrigation from wells. Even wells are

* Nouveau Diction naire ile Geograpliie Universelle. Paris, 1877. Article " Arabic."
t Quoted by Vivien de Saiiit-Martiu, 1. c, Vol. I. p. 74.

ARABIA. 139

rare. The general character of the central plateaus, and of the penmsula,
is that of vast uplands of gravel, as nearly destitute of vegetation as any in
the world, and incapable of retaining water, even at a great depth. It is
only in certain de^jressions of the plain, several hundred feet lower than the
general level, that wells as a rule are found, and wherever this occurs with
a sufficient supply of water, towns and villages, with gardens round them,
have sprung up. These, however, are often widely apart, showing in mere
spots on the map of Arabia, and unconnected with each other by any inter-
vening spots of agricultural land." *

Mr. Blunt, in his " Notes on the Physical Geography of Northern Arabia,"
appended to Lady Anne Blunt's book, speaks repeatedly of the depressions
in tlie desert, as having once been filled with water. For instance, in his
description of the Wady Sirhan he says : " In the days when it was an inland
sea, it must have received contributions from all sides." f Farther on, in
speaking of the same Wady, he remarks as follows : '• It is probable that in
the days when Arabia was more populous than now, villages existed in it at
intervals from Ezrak to Jof At present, the wells of these only remain,
if we except the twin oases of Kaf and Ithery, still preserved in life by the
salt lakes which supply them with an article of trade. These are but jjoor
places, and their population can hardly exceed 200 souls."

It will not be necessary to make farther citations in regard to the desic-
cation of Arabia; that the population of that country has greatly dimin-
ished, seems evident ; but since the actual population is not known with
even an approximation to accuracy, no statistics can be given, t

For the region north of Arabia, including Asia Minor, Sj-ria, and Mesopo-
tamia, fiicts of the kind stated above in reference to Arabia and Persia are
everywhere presented to the investigation of the traveller. A few only of
those lately published need be quoted. In a " Memorandum on the Eu-
phrates Valley Railway," Mr. W. Blunt — to whom reference has already
been made — notices repeatedly the depopulation of the region traversed by
that river. He remarks as follows : " I think it more than jirobable that
in the day of Bab^donian greatness the flooding of both rivers [the Tigris
and Euphrates] was more regular, and less subject to disastei's of drouth and

* A Pilgrimage to Nejd. Bj- Lady Anne Blunt. London, ISSl. A'ol. I. p. 258.

t 1. c, Vol. II. p. 237.

t For some time 12,000,000 wa-s given, in the geographical text-books, as tlie population of Arabia ; this
number was, in 1S59, suddenly reduced by the best authorities to "about 5,000,000." (See Behm's geograph-
isches Jahrbuch, Band I. 1866, p. 59. ) Even this number may be considerably too high.

140 THE DESICCATION OF LATER GEOLOGICAL TIMES.

excess than now. As I have said, the denudation of Armenia accounts per-
haps for the destruction of Irak. In any case it is certain, that at the pres-
ent moment the full energies of the existing population are required to
preserve their footing, not to make new conquests on the river. Now, as I
am writing, Lower Mesopotamia is expecting famine from the failure of the
Tis^ris, for not an acre of wheat can be sown without its floodins." *

The following is quoted from Dr. C. Fraas : " The most fruitful land of
antiquity was, as is well known, the region bordering on the Lower Eu-
phrates and Tigris, and particularly that called in later times Mesopotamia.
As the sacred writings of the Hebrews have assigned this as the country
from which the founder of their religion emigrated, it is an attractive sub-
ject to compare its former with its present fruitfulness. As Eichter says,
the land of great canals is now desert and barren, without settlements,
and a dried-up wilderness. The once most fertile alluvial bottoms, inter-
sected by numerous lines of canals and ditches, are now covered with a
growth of the plants peculiar to a saline soil, and all this where once was
the ' garden of the world.' " f

Professor E. H. Palmer gives a number of quotations from the Jewish
sacred books, which, he says, " tend to confirm the supposition that the Pe-
ninsula [of Sinai] was better supplied with water at the time of the Exodus." t
He considers it certain that there was, at that time, a large population in
and near Sinai ; and among them were colonies of Eg3'ptian miners, " whose
slag-heaps and furnaces are to be seen in every part of the Peninsula. These
must have destroyed many miles of forest in order to procure the fuel neces-
sary for carrying on their operations ; nay more, the children of Israel could
not have passed through without consuming vast quantities of fuel too.
But if forest after forest disappeared in this way, if population dwindled
down to a few non-agricultural tribes, and cultivation were neglected, then
the rain that falls so seldom would no longer stay to fertilize the land, but
in an unimpeded torrent would find its way to the sea; a burning summer
sun would soon complete the work, and a few ages would make the Penin-
sula of Sinai what we see it now."

Captain Burton says : " That great changes for the worse have taken place
in the Sinaitic Peninsula, and in the Negeb, or South Country, we know from

* A Pilgrimage to Nejd, Vol. II. p. 276.

+ Klima und Pflanzenwelt in der Zeit, ein Beitrag zur Geschichte beider, von C. Fraas. Landshut, 1847,
p. 20.

t The Desert of the Exodus. 2 vols. London, Vol. I. p. 25.

EGYPT. 141

the expeditions of Messrs. Tyrwhitt-Drake and Palmer, who found undoubted
traces of rich pasturages of watered ground and of human habitation, where
all is now a howling waste." * Farther on, the same author remarks: " The
once wealthy and commercial land of Midian, now 'destitute of that whereof
it was once full,' has become a desolation among the nations. The cities and
goodly castles of the sea-board are ruinous heaps, almost level with the
ground. 'The Desert has resumed its rights; the intrusive hand of cultiva-
tion has been driven back ; the race that dwelt here have perished ; and their
works now look abroad in loneliness over the mighty waste.' The interior,
formerly so rich in oases if not in smiling field and pasture-land, has been
disforested to a howling wilderness ; and the area of some three thousand
square miles, which, thirty-one centuries ago, could send into the field
135,000 swordsmen, is abandoned to a few hundi-eds of a mongrel Egypto-
Bedawi race, half peasants, half nomads, whose only objects in life are to
plunder, maim and murder one another." f

Of the very large amount of matter which could be laid before the reader
proving, beyond the possibility of doubt, that the climate of the region bor-
dering the Mediterranean on the south has undergone a marked change in
later geological times, and that this has been continued into the historical
period, only a small portion will be presented. As has already been made
apparent from the tenor of some of the quotations offered, the almost uni-
versal belief is, that the indicated change of climate has been chiefly brought
about by the disforesting of the country, or perhaps also in part by long-
continued cultivation. All, however, that is intended, in the present section,
is to show that a change from prosperity to stagnation, from fertility to bar-
renness, and from favorable climatic conditions to utter dryness, has affected
the whole area in question. Of the cause of this, the discussion will follow
farther on.

The first quotation is from the work of C. Fraas, already cited, and it
relates to the proofs of a change of climate in Egypt during historical as
well as prehistoric times. This author thus expresses himself: " As we
have already repeatedly had occasion to notice what gi-eat revolutions have
been brought about by changes of climate, we shall find no difficulty in
proving this in regard to a country which has been so long inhabited as
Egypt. Long before our time attention was called to these changes by

* The Gold Mines of llidian and the Ruined Midianite Cities. 2d ed. London, 1878, p. 290.
t 1. c., p. 391.

142 THE DESICCATION OF LATER GEOLOGICAL TIMES.

Russegger, who recognized in the deep gorges of the desert mountains,
in the deep Ghors, or torrential stream-beds of tropical Africa, the results
of long-continued and heavy rains in former ages. Certainly, at the time
when the country was at the height of its prosperity, when it was traversed
by numerous canals, when artificial lakes, such especially as Lake Moeris,
covered it, when cultivation extended fur beyond the present boundaries
of the desert — when all this was the case, certainly the climate must have
been very different from Avhat it now is. What mean all those petrified
remains of various kinds of trees wliich are so frequently found in Egypt?
The tradition that Lower Egypt at least was once an arm of the sea? The
once larger area of alluvial plain, and the very much larger water-surfaces
exposed to evaporation ? The plants, finally, in regard to which Ave intend
to give more details farther on, and of which plants some, like the Nelumbo,
require a very moist soil, and which, formerly the pi'incipal article of diet, has
now entirely disappeared from Egypt?"*

Fraas, after a brief discussion of Russegger's ideas in regard to the causes
of the desiccation in question, to which we shall have occasion to revert
farther on, proceeds to give numerous instances of changes in the distribution
of plants, especially of cultivated ones ; which changes have taken place in
later geological times, and which seem to him to prove a marked decrease
in the amount of moisture.

Mr. Andrew L. Adams, in his account of an examination of the so-called
petrified forest of the Mogattam Hills, writes as follows : " This silicified
wood deposit appears to belong to a more recent epoch than the nummulitic
rocks, and may be referable to a period immediately preceding the submer-
gence of the Sahara and general depression of North Africa just noticed ; or,
in other words, contemporaneous with the age when the river flowed over
the plateaus of Nubia. No traces of ancient levels or terraces were observed,
but about Beni Hassan we could define terraced cliffs on the sides of the
long straight glens, also ravines and larger valleys, which may in part have
been formed by the denuding influence of the sea, during the oscillations of
level, and since farther opened out by atmospheric agencies. No doubt more
extended observations would elicit important data in connexion with this
interesting subject. Who can tell how far the Egyptian priests erred when
they informed Herodotus that at the time when Menes, the first mortal,
reigned over EgApt ' all the country except the district of Thebes was a

* Klinia unci Pflanzenwelt, p. 41.

EGYPT AND GEEECE. 143

morass, and that no part of the land that now exists below Lake Mjris was
then above water ' ? "*

Mr. Adams, farther on, remarks, in reference to the constant encroachment
of the desert sands on the arable lands of Eg^-pt : " Already many arable
plains are covered over; indeed the gradual desertion of entire villages, and
the partial evacuation of others, are just in proportion to the steady en-
croachment of the desert. The struggle between man and nature is here
remarkable, for, should the present order of things be continued, it must
finally eventuate in a complete victory to the latter whenever the odds are
favorable." f

Professor Unger, in his interesting work describing his scientific journeys
in Greece, t has a chapter headed, "Is the Orient capable, so far as its
physical nature is concerned, of regeneration?" ["1st der Orient, von Seite
seiner physischen Natur, einer Wiedergeburt fahig?"] The views which the
author sets forth in this chapter, in reference to changes of climate in the
vicinity of the Mediterranean, will be noticed farther on ; at present, only
one quotation will be made, for the purpose of introducing the views of
Fallraerayer, an eminent Oriental traveller and historian whom Unger thus
cites: "As to what especially relates to Greece, Fallmerayer has already
called attention to the fiict that, together with an entire change in the
races inhabiting ancient Hellas, its capacity for production has changed
with the climatic conditions; that, instead of the former fruitful and well
watered meadows and pastures, now only dry fields and bosky hills devoid
of forests are to be found, and that, in consequence of this, it is impos-
sible that Greene should ever be again drawn within the circle of Western
culture. Fraas has brought forward the same idea, and supported it by
additional proofs." § It may be added that Fraas extends these views so
as to embrace the whole region adjacent to the " lands of the ancient home
of culture," including Persia, Asia Minor, Syria, Greece, and Egypt.

Professor 0. Fraas, 1| in his investigations of the physical geogiaphy of

» In Notes of a Naturalist iu the Nile Valley and Malta. Edinburgh, 1870, p. 66.

t 1. c, p. 70.

t Dr. Fr. Unger : Wissenschaftliche Ergebnisse einer Eeise in Griechenland nnd in deu lonischen lusela.
Wien, 1S62, p. 18S.

§ See, Gesammelte Werke von Jakob Philipp Fallmerayer. 3 vols. Leipzig, 1861, Vol. II. p. 468 ; also the
preface to Geschichte der Halbinsel Mores, wahrend des Mittelalters, by the same. 2 vols. Stuttgart, 1830.

II Dr. C. Fraas, " Inspector und Lehrer der Chemie und Teuhnologie an der konigl. Centrallandwirthschafts-
Schule zu Schleissheim," is not to be confounded with Dr. Oscar Fraas, "Conservator an der konigl. Naturalien-
Cabinet zu Stuttgart."

144 THE DESICCATION OF LATER GEOLOGICAL TIMES.

the countries bordering on the Mediterranean, gives his attention espe-
cially to the increasing dryness of that region, referring repeatedly to the
proofs of a change of climate in those countries during the historic period.
Of the many quotations, in point, which might be made from his work,*
the following is selected : " What a difference between this idea of life
[Lebensanschauung], held in ancient Egypt, taken from the City of the Dead
of Saqara and the pyramids, and the idea of life drawn from the royal
graves of Qiirna and Medinet Habu. It is hardly possible to say which
required the longer time, the changes of popular belief [Volksglaube] or
the introduction and dissemination of new domestic animals. The camel
is still wanting even on the walls of the temples of Thebes, and had cer-
tainly not been introduced at the time of the founding of that city, for there
was no desert then. Magnificent buildings, such as those in the Assassi
Mountain, or in Denderah, and the giant structures of the world, on which
we gaze, at the present time, with the dee^iest feeling of our own insignifi-
cance [Armseligkeit] — such buildings were not placed away to one side in
the desert, whei-e they could only be reached with difficulty and danger.
Thousands of walls were not covered, from floor to roof, with inscrip-
tions, paintings, and scul2)tures, that they might remain unseen in the
night of the grave ; but that the writing might be read, and the works of
art inspected. The remains of both the most ancient, and the ancient^
Egypt speak as loudly of the changed climate of the Nile-lands as do the
gravels [Gertille] in the Wadys of the Libyan desert of former floods of

water, where now, year out and year in, no drop of water ever flows

An intellectual activity like that of the times of the Greeks, when Alex-
andria was the centre of all the arts and sciences, a true world's university,
with the richest library on earth ; or as that which existed from the times
of the Platonists up to the first centuries of the Christian era, when the
greatest thinkers of the church — such as the Gnostic Origen — developed
their philosophical-religious systems, — such a movement of thought de-
mands, as an absolute necessity, a different climate, and a moister air, than
that now prevailing in Egypt. On the present soil of the Nile-land never
again will any philosophical system be developed ; and no power in the
world could cause an University to arise there which should have even the
most distant resemblance to an European one."

* Aus dem Orient ; Geologische Beobachtungen am NU, auf der SiDai-Halbiiisel, uud in Syrien. Stuttgart,
1867.

THE EEGION ABOUT THE MEDITERRANEAN. 145

From the above quotation it will be easily made out that Fraas considers
that there is no avoiding the conclusion that the Mediterranean region —
the eastern portion of it, at least — has undergone a most decided climatic
change, not only in later geological times, but within the past 2,000 years.

Professor Zittel, when speaking of one of the oases of the Libyan desert, —
that of Chargeh, — says : " In many places there are to be seen in this oasis,
where now all is sterile, old ruins of sacred and profane buildings, traces of
fields formerly under cultivation, wells which have caved in; — in short, a
host of proofs of a former much larger population of this region." * Profes-
sor Zittel takes, however, a much less disparaging view of the condition of.
things in this portion of Egypt than does Dr. Fraas, since the former believes
it not impossible that, if Artesian tvells could be successfully bored, the Libyan
desert might return to its former condition of prosperity. That condition,
however, if we may judge from the character and habits of the population
of that portion of the Sahara where such wells have, to a certain limited
extent, succeeded, would have but a very slight resemblance to what we are
now accustomed to consider as civilization. Wandering tribes living almost
exclusively on the fruit of the date-palm, such as they are described by
Desort and others, have little in common with the dwellers in coun-
tries better supplied with water. Nor is any instance to be found on
the face of the earth of a people living in prosperity and 3'et dependent
exclusively on Artesian water. Indeed, as appears clear to the present
writer, the Artesian wells of the Libyan desert have not run dry because
the country has been abandoned ; but the case is exactly the opposite of this,
— the water having given out, life is no longer possible except under con-
ditions in the highest degree unfavorable to prosperity.

In regard to the extensive area to the west of EgA^pt, including Tunis,
Algiers, and the vast region of the Sahara, we have an abundance of obser-
vations, made within the most recent period, by eminent observers, all tend-
ing to prove, almost bej-ond possibility of doubt, that conditions similar to
those described as existing farther east, along the Mediterranean, and be-
yond it through Central Asia, prevail here, and on quite as extensive a
scale. As in the Libyan desert, and in Syria and Arabia, the whole aspect
of the surface is that of a region at no very distant time in the past quite
abundantly watered, l^iit now given over, in large pait, to almost hopeless

* Briefe ans der Libyschen Wiiste. Jliinclieii, 1875.
t Aus Saliara iiml Atlas.

146 THE DESICCATION OF LATER GEOLOGICAL TIMES.

sterility. As on the eastern borders of the Mediterranean, so farther west,
there are abundant evidences of tlie former presence of nations possessing a
much higher grade of civiUzation than that of the present population, whose
numbers have dwindled with their diminisliing intelligence, and whose habits
and modes of life, while eminently suited to the physical conditions by which
they are surrounded, are beyond a doubt incompatible with what is now
called civilization. Everywhere the ruir.s of former greatness are to be seen,
offering a striking contrast to the present struggle for mere existence neces-
sitated by the diminished area susceptible of cultivation, and the impossi-
bility of procuring a sufficient supply of water for irrigation, except in a few
favored localities, of exceedingly small dimensions as compared with the
extent of the surrounding desert.

The recent explorations of the Sahara have resulted in the correction of
some of the former erroneous impressions prevailing in regard to the real
causes of the increased dryness of that region. The examinations made
by Desor of a limited area, on the northern edge of that part of Africa
known as the Desert of Sahara, led him to form the idea — which, for a
time, was very generally adopted — that the whole of this vast region had
formerly been covered by the sea, and that it had been raised above water
during the very latest portion of the Tertiary epoch. This elevation of the
land, according to Desor, brought about not only the dryness of the Sahara
itself, but had a powerful influence in putting an end to the phenomena of
the glacial epoch, as will be mentioned farther on.

It is now known, however, that only a small part of the Sahara has been
covered by the sea at any period since the Cretaceous epoch. On the con-
trary, we find everywhere abundant proof of the former presence of fresh
water, which stood in lakes or ran in rivers; and, of course, a corresponding
amount of evidence that there has been a marked change of climate during
recent periods. In fact, there seems to be little doubt that this change,
whenever begun, has been continued during the historic period, the kind of
evidence furnished by recent investigators being precisely similar in charac-
ter to that already brought forward in reference to Syria, Egypt, and the
Libyan desert. The remains of buildings of various dates, as well as the
records of history, show conclusively that large ]iortions of Northern Africa
were once much more thickly populated than they now are ; but that the
stage of civilization then reached was far higher tlian that of the present
inhabitants, whose mode of life is strictly in accordance with the conditions

THE SAHARA. 147

imposed on them by the desert nature of a country where only an occa-
sional oasis can, by artificial irrigation, be made to bear fruit enough to give
a scanty suppoi't to a limited population.

Dr. Chavanne has, so to speak, monographed the Sahara,* and given a
very complete resume of all that has been found out about that region up to
a very recent date. His views, which appear to the present writer to be, in
the main, justified by the facts, may be inferred from the following quota-
tions : " Up to the most recent period, it was generally thought to be a fact
which could not be controverted, that the Sahara had been, dui-ing the most
recent geological period, one great inland sea, and that, consequently, the
dunes, or accumulations of sand of the present sea of that material, which
cover the region, were the relics of that sea. The existence of numerous
schotts, sebchas and salt morasses, the discovery of brackish-water shells
( Cardium edide) in the northern part of the Sahara, at an elevation of from
200 to 300 meters, seemed to prove the ti'uth of this theory beyond possi-
bilit}' of dispute. The well-known German geologists, Desor and Escher
von der Linth. who in 1863, in company with Professor Martins, of Mont-
pellier, made a journey to the Algerian Sahara, published results of their
observations which appeared to confirm the hypothesis in question ; and
De.sor carried the theory still fiirther, inasmuch as he endeavored to show
that the Sahara was the ffrand regulator of the climate of South and Middle
Europe, and to connect the extension of the Alpine glaciers with the former
watery covering of Northern Africa. However enticing [verlockend] this
theory may be, it is not supported by the facts. The first impression which
the traveller gets of the desert, especially when standing on the southern
slope of the mountains bordering the Sahara on the north, is indeed highly
favorable to the hypothesis of a former occupation of this region by the sea.
The writer himself, when visiting the northern edge of the desert, was led
to look on this theory as most probably correct. An exhaustive and un-
prejudiced examination of the mode of formation of the sand accumulations,
the consideration of indisputable facts, such as the existence of crocoddes
in the heart of the Sahara, and of petrified forests in the Libyan oases, can-
not but lead to the conclusion that the present sandy regions owe their
existence to some other cause than that of a former universal water cover-
ing. Humboldt long ago recognized the influence of general geographical

* In his volume entitled "Die Sahara, odev von Case zu Case." Wien, 1879. See also another later work, by
the same author, " .-Vfrika ini Lichte unserer Tage." Wien, 1881.

148 THE DESTCCATIOX OF LATER OEOLOGICAL TIMES.

position on the formation of desert regions ; and later investigations, like
those of Diivejrier, Dr. Mares, and Vatonne, made on the spot, in regard to
the formation of sand dunes, as well as those of Hann and WojeikofFon the
influence of meteorological conditions on the desert surface, render the con-
ception of the desert as the product of climato-meteorological changes more
and more probable. It is not intended, however, by this, to assert that,
during the latest geological period, numerous larger and smaller inland lakes
may not have existed in the Sahara ; on the contrary, we are obliged to
recognize the numerous sebchas and dayas as the remains of such fresh- or
brackish-water collections. In the Western Sahara, at all events, these lakes
did not have any great extension during the Quaternary epoch, and they
were separated by the previously mentioned range of elevations from the
great inland sea, which occupied the place of the present sea of sand of the
Libyan Desert. The correctness of this view appears to be fully confirmed,
by the fact that, up to the present time, no marine deposits or fossils have
been found in the western basin, while such are by no means wanting in the
Libyan Desert.

" In the present distribution of certain animals we find strong reasons
for believing that, even in historical times, the Sahara was less extensive
and less of a desert than it now is. First ; the late introduction of the
camel, which was not domesticated in Northern Africa luitil one or two
centuries after the birth of Christ. Again ; there must have been in the
Southern Atlas, in ancient times, numerous wild elephants, since we know
that the Carthaginians caught their war-elephants within their own territory.
So, too, the hippopotamus existed in a region where now it could not, by
any means, find sufficient water, the same being the case Avith the elephant
as respects food. Crocodiles, which in former times occurred in prodigious
numbers, were also supposed to have died out ; but, not long since, a French
traveller. Baron Aucapitaine, found some still living in the Wadi-el-Dscheddi ;
and, still more recently, Edwin von Bary proved their existence in the
uninhabited valley of Mihero, on the Tasili plateau. The former occurrence
of all these animals in the Northern Sahara, which in its present condition
would present an insurmountable barrier to their introduction from the
South, renders the adoption of the hypothesis of a former more luxuriant
vegetation and m.ore abundant precipitation where now there is only desert,
a matter almost of absolute necessity. In general it may be said that, south
of the 34th parallel, in this region, there has been a constant advance of the

CENTRAL AND SOUTHERN AFRICA. 149'

desert since the historic period [seit dem Alterthiime die Wiistenbildung,
ohne Unterbrechimg im Fortschreiten begriffen ist]."

Farther on, Chavanne remarks as follows : " That, however, the quantity
of water [der Wasserschatz] in the Sahara has diminished, and that this
region has become drier since the days of historical antiquity, can now be
no lon2;er doubted." *

The evidence of a great climatic change in Northern Africa, and generally
in the countries bordering the Mediterranean, is so clear, that it is not neces-
sary to dwell longer upon this region. As to the central and southern por-
tions of that continent, it is not to be expected that such an array of facts
as has been presented with regard to Egypt and the Sahara could be brought
forward, even if desiccation had proceeded all over Africa with the same
rapidity as on its northern borders. In the first place, the central portion
of that continent is quite differently situated from the northern area with
reference to those meteorological conditions influencing precipitation, so
that the larger part of it is superabundantly supplied with moisture, at
least during a certain season of the year. And a diminution of an abundant
supply to one less abundant, but still ample for the wants of animal and
vegetable life, is not, by any means, a phenomenon of the same character
as that of a falling-ofF from moderate to very small, although, in reality,
the actual decrease ma}^ be as great in one case as in the other. It is only
when the decrease of precipitation has reached that point Avhere its effects
begin to be marked in making life difficult, that much heed would be likely
to be paid to it.

But, again. Central Africa is a region which is inhabited by uncivilized
races, and of which the scientific exploration has but just begun, the prin-
cipal geographical facts concerning it being, as yet, hardly made out in
outline. Moreover, it has no recorded history, other than that offered
by nature herself; while data furnished by trained geological observers are
entirely wanting, at least for much the larger portion of the country. The
existence of numerous lakes, many of which are of great size, so that the
whole region is one of the most remarkable, in respect to the importance
of its lacustrine areas, of any on the globe, is, however, now a well-ascer-
tained fact, and evidence that these lakes have been diminishing in size during
recent times is by no means wanting. Indeed, that most remarkable trav-
eller, Livingstone, seems, at an early period of his investigations in Africa,

• 1. c, p. 627.

150 THE DESICCATION OF LATER GEOLOGICAL TIMES.

to have been profoundly impressed ^vith the appearances which presented
themselves in various localities of a former much greater expansion of the
Inke system, both of Central and Southern Central Africa, as the following
quotations from his principal volume prove :".... consequently, when the
river [Lekone] flowed along this ancient bed, instead of through the rent,
the whole country between this, and the ridge beyond Libebe westwards ;
Lake Ngami and the Zouga southwards ; and eastwards beyond Nchokotsa,
was one large fresh-water lake. There is abundant evidence of the exist-
ence and extent of this vast lake in the longitudes indicated, and stretching

from 17° to 21° S. latitude All the African lakes hitherto di.'^covered

are shallow, in consequence of being the mere residua of very much larger
ancient bodies of water. There can be no doubt that this continent was,
in former times, very much more copiously supplied with water than at

present, but a natural process of drainage has been going on for ages

Whether this process of desiccation is as rapid throughout the continent, as
in a letter to the late Dean Buckland, in 1843, I showed to have been the
case in the Bechuana country, it is not for me to say." *

Livingstone's ideas in regard to the diminution of some of these lakes and
the disappearance of others need not here be dwelt upon. Naturally, they
are highly catastrophic in character, the idea of a possible diminution of the
rain-fall not having occurred to him, although the facts which he furnishes
seem very clearly to point in that direction, rather than towards drainage by
earthquake fissures and the like events.

The entire aspect of Southern Africa, as described by recent travellers, is
that of a region which has undergone great changes of climate within a
recent period. Dryness is pre-eminently its characteristic at the present
time; but in tlie whole appearance of the country there is proof — as it
appears to the writer — that this dryness has been on the increase since
the southern part of the continent acquired its present topography. There
has certainly been a great diminution of the water-surface since the Tertiary
epoch began.

A considerable portion of Europe belongs in the same category as North-
eastern North America in its relations to the question now before us. The
phenomena of desiccation are complicated with those of former glaciation, so
that it is not so easy to separate the two classes of facts from each other :

* Missionary Travels in South Africa. London, 1857, Chapter XXVI., under the heading of " Ancient
Lakes."

CENTRAL EUROPE. 151

hence the special considerations of the decrease of moisture in formerly gla-
ciated regions will be deferred for the present. A few remarks will, however,
be made, at this point, in reference to an interesting fact, namely, the de-
crease of the volume of the rivers of Central Europe during the later historic
times.

In some portions of Germany records have been kept for many years of
the flow of water in some of the principal rivers, and the question naturally
suggested itself, whether a comparison of these records would show that the
volume of water passing from 3'ear to year, at various points, had dimini.-hed
or increased, or on the other hand remained constant. The eminent geog-
rapher, Berghaus, was one of the first to take up this investigation. He
worked up the observations of the Rhine made at Emmerich, those of the
Elbe at Magdeburg, and those of the Oder at Kiistrin, and came to the con-
clusion that each of these rivers had diminished in volume during the past
hundred years, and that there was reason to fear that they would eventually
disappear from the list of the navigable streams of Germany.

Later than this, an eminent hydraulic engineer, Gustav Wex, Chief Direc-
tor of tlie Donauregulirung, — an important work imdertaken with a view
to the regulation and improvement of the channel of the Danube at and
near Vienna, — entered upon the same investigation, and in much greater
detail. His results, however, are similar in character to those of Berghaus,
and seem to demonstrate, beyond possibility of doubt, that the principal
streams of Middle Europe, namely, the Danube, the Rhine> the Elbe, the
Vistula, and the Oder, together draining an area of 570,000 sqiiare miles,
have for many years been carrying a constantly diminishing quantity of
water. The longest series used in coming to this conclusion is that of the
Elbe at Magdeburg, where the records go back for one hundred and forty-
two years ; but the observations for shorter periods of from fifty to seventy
3'ears, which in the case of the other streams are all that are available, seem
to leave no doubt as to the character of the result.*

We turn, finally, for evidence of desiccation to the southern counterpart
of our own continental mass. Striking as is, in many respects, the resem-
blance in orographic structure between North and South America, there is
one point in regard to which the diflfeience is ver}' marked. The Cordilleras
of North America form a complex of ranges which occupy a very consider-
able width, not less than a thou.sand miles in their widest portion, while the

* See Zeitschrift ties u.st. Ingciiieui" und Aruliitekteu \'iTeiiis, for 1S73.

152 THE DESICCATION OF LATER GEOLOGICAL TIMES.

Ancles of South America are much narrower, a section east and west across
them hardly averaging more than a third in length of that of a similar line
across the North American Cordilleras. Of course, under such conditions, it
is to be expected that the closed-basin region of South America, if one ex-
isted at all, would be much less extensive than our own. This is, in reality,
the fact, the drainage of a large part of the interior portions of the Andes
being very completely effected by the branches of the great rivers which
traverse the ranges by means of immense transverse breaks across them.

Another important fact to be taken into consideration in this connection
is this : that the wide part of South America lies ■wholly in the tropical
regions, and is therefore subject to a very different regime from that of an
area within the temperate zone, like our own Cordilleras. The rain-fall of
the South American continent is very peculiarly affected, however, by the
position of the mountain ranges with reference to the trade-winds. Closed-
basin areas do exist in the Andes, and here, as we might have expected,
from analogy with the facts already described fiom our own western regions,
there are also clear evidences of desiccation in recent geological times.

The closed basin occupied in part by Lake Titicaca is the most important
area of this kind in the Andes, and from the description furnished by
A. Agassiz* it is possible to state as an unquestionable fact, that the area of
water-surface not only of this lake, but of the region generally, has greatly
diminished in later times. The following quotation is offered in support of
this statement.

" Lake Titicaca must have, within a comparatively very recent geological
period, formed quite an inland sea. The terraces of its Ibrmer shores are
everywhere most distinctly to be traced, showing that its water-level must
have had an elevation of 300 or 400 feet at least higher than its present
level. This alone would send its shores far to the north in the direction of
Pucara, forming a narrow arm reaching up to S. Rosa. Lake Arapa is prob-
ably only an outlier of the ancient lake, as well as several of the small lakes,
now at a considerable distance from the west shore. The immense plain of
Cabanillas, extending north beyond Lampa to Juliaca, only 100 or 120 feet
above the lake at its highest point, was one sheet of water. The terraces of

the former shores are still very distinctly to be seen The plains, now

laid bare at the northern and western shores of Lake Titicaca, give us an
excellent idea the appearance the whole basin of the lake would present if

* Hyilrogniphic Sketch of Lake Titii-aca ; Piuc. Am. AcaJ., Vol. XI. 1876, p. 2S8.

SOUTH AMERICA. 153

entirely dry. The number of lakes and basins, great and small, which for-
mei'ly covered the elevated plateau of the Andes, must have been very great;
but we now find only here and there a small sheet of water. The former
lakes are only represented by the more or less extensive pampas, forming
basins at great altitudes, showing plainly that the whole of this district is
receiving a much smaller waterfell tlian in former times, but probably not in
historic times, if we take into consideration the position of some of the most
ancient ruins of Bolivia (at Tiahuanaco), which are onlv about seventy-five
feet above the present level of the lake."

The diminution of the water, shown by Mr. Agassiz to be so positively
proved for the region embraced within the field of his explorations, did not
escape the notice of Humboldt ; on the contrary, he repeatedly calls atten-
tion to the foct of a general desiccation in those parts of South America
which he visited, and he comments, somewhat at length, on the cause of the
phenomenon. The decrease in size of the Lake of Valencia, near Caraccas,
especially interested him, as will be evident from the following quotation :
" But it is not alone the picturesque beauties of the Lake of Valencia that
have given celebrity to its banks. This basin presents several other phenom-
ena, and suggests questions, the solution of which is interesting alike to
science and to the well-being of the inhabitants. What are the causes of
the diminution of the waters of the lake ? Is this diminution more rapid now
than in former ages ?....! have no doubt that, in very remote times, the
whole valley, from the foot of the mountains of Cocuyza to those of Torito
and Nirgua, and from La Sierra de Mariara to the chain of Guigue, of Gua-

cimo, and La Palma, was filled with water Within half a century, and

particularly within these thirty years, the natural desiccation of this great
basin has excited general attention. We find vast tracts of land which were
formerly inundated, now dry, and already cultivated with plantains, sugar-
canes, or cotton. Whei-ever a hut is erected on the bank of the lake, we see
the shore receding from year to year. We discover islands, which, in con-
sequence of the retreat of the waters, are just beginning to be joined to the
continent, as for instance the rocky i.sland of Culebra, in the direction of
Guigue ; other islands already form promontories, as the Morro, between
Guigue and Nueva Valencia, and La Cabrera, southeast of Mariara ; others
again are now rising in the islands themselves like scattered hills."*

Humboldt continues, at length, with the narration of similar facts, proving

• Personal Narrative of Tr.iTels to the Eciuinoctial Regions of America. Bolin's Ed. in 3 vols. Vol. II. p. 4.

154 THE DESICCATION OF LATER GEOLOGICAL TIMES.

desiccation in this portion of South America, and enters into a discussion as
to the causes of the phenomenon, to which we shall have occasion to revert
farther on.

It seems unnecessary to multiply evidence of the kind given in the preced-
ing jiages. The fact cannot fail to have impressed the reader that, however
striking the phenomena of desiccation may have been shown to be in our
own western region, they are not less so in the Old World ; where we have
an additional interest imparted to the investigation, by the fact that we
have here to do with the historically important portion of the world, so that
the connection of the desiccation with the growth, migrations, and decay of
civilized nations makes it a matter of the utmost importance. In the course
of the next chapter additional information will be, of necessity, introduced, in
regard to the phenomena which have occupied us during the present one.
Having shown the fact of a desiccation going on at least during the later geo-
logical periods, and continuing up to the present day, certainly over a large
part of both hemispheres, in botli the Old and New Worlds, we are now pre-
pared to proceed with the discussion of the facts presented, and to endeavor
to ascertain what cause or causes have been influential in bringing about the
condition of things described. That the problem is a complicated and diffi-
cult one will not be denied ; but it is hoped that, in the following chapter,
some light will be thrown upon it, even if there are questions raised to
which it is not easy to give an entirely satisfactory answer.

CHAPTER III.

GENERAL DISCUSSION OF THE DESICCATION QUESTION.
Section I. — Lrtrodmtory .

It will be proper, at the present stage of our investigation, to recapitulate
what has been set forth and shown to exist, in connection with the prob-
lems of climatic change, in the preceding chapters of this work, and in a
former one (the Auriferous Gravels), to which frequent reference has already
been made, and to which the present volume may properly be considered as
supplementary.

As one of the important results to which we were led by our extended
examination of the detrital formations resting on the western slope of the
Sierra Nevada, we have the — as it appears to the present writer — un-
doubted fact presented to us of the former existence, throughout that region,
of much larger rivers than tliose whose channels now furrow that slope.
These rivers had, however, on the whole, pretty essentially the same gather-
ing-grounds which their present much diminished representatives have ;
hence it follows, as a matter of course, that the former precipitation must
have been very considerably larger than it now is. This condition of things
prevailed during a portion of the Tertiary epoch, probably during a large
part of the Tertiary, and certainly during the later Pliocene. If it cannot
be definitely stated that this increased precipitation also prevailed during
the earlier Tertiary period, it is only because Eocene fossils have not been
distinctly recognized as occurring in the detrital formations in question, so
that the means of going back to the beginning of the Tertiary epoch are
not furnished. There is no evidence, however, that the precipitation over
the region in question was, during the earliest portion of the Tertiary, any
smaller than it was later on in that period ; on the contrary, there is some
reason for supposing it to have been larger. So much has been set forth in
detail in the Auriferous Gravels.

Pursuing our investisrations still farther, we have seen, as described in
the first chapter of the present volume, that long after the deposition on the

156 DISCUSSION OF THE DESICCATION QUESTION.

flanks of the Sierra Nevada of the gravels which belong to the period of
increased precipitation, and after the present diminished rivers had worn —
in large part, at least — their deep but narrow channels down the sides of
the range, there came a time when the higher portions of the Sierra were
covered with accumulations of snow, from which glaciers of great size ex-
tended down the valleys, some of these icy masses attaining dimensions not
much, if at all, inferior to those of the Alps at the present day. It was
farther shown that these glaciers had now almost entirely disappeared, only
the faintest traces of ice being left in a few localities, and especially about
the north side of the summit of Mount Shasta, while reasons were adduced
for believing that this disappearance of the ice has taken place within a very
recent period, and most certainly since the appearance of the human race
in that region. In regard to the snow accumulations of the range in ques-
tion, it was shown that they vary greatly in amount from year to year ; and
that, although they never disappear entirely from the whole of the Sierra,
oven after the occurrence of a cycle of abnormally dry years, they some-
times shrink into entire insignificance, as compared with the mass of the
range, occupying only small sheltered nooks on the summits of the higher
elevations.

With this foundation of facts, observed and studied with great care in the
region which was the especial field of work of the present writer for some
fifteen years, the attempt was made to find out how far a similar condition
and succession of phenomena could be traced in other regions ; and first in
those adjacent to the Californian Sierra ; then, later, in otliers more distant ;
until, finally, the inquiry extended itself so as to embrace tlic Avliole earth ;
and very naturally and properly, for the subject of climatic change is one
which cannot be discussed with satisfaction while only narrow areas are
under consideration, as must be evident from the nature of the phenomena
themselves, the climate of any one locality being the result of a complex
series of events, many of which have taken place at a great distance from
the special locality where they become sensible to the inquirer. In thus
extending the investigation over regions outside of California, the pres-
ent writer has not been obliged to depend entirely on the work of others,
although such has been consulted and freely used ; he has been assisted by
his own investigations, which at various times during the past forty years
have been extended over a considerable portion of North America, and have
also embraced the most important glaciated regions of Europe.

INTRODUCTORY. 157

This extension of the investigation begun in the Sierra Nevada has fur-
nislied us with interesting resuhs, in a great measure corroborating those
obtained on the Pacific slope of tlie continent. Tliat the diminution of
the rivers flowing down the western slope of the Sierra could be so fully
proved, was due to the peculiar facilities offered by the extremely numerous
and extensive mining operations carried on in and about the former chan-
nels of these "buried rivers," as thev have sometimes been called; and
although the same kind of proof could not be furnished bearing on the dimi-
nution of the precipitation in portions of the continent adjacent to Cali-
fornia, a large body of focts was brought forward showing that an extensive
area of country west of the Rocky Mountain range was formerly covered
by water, in the form of lakes, which lakes have either disappeared alto-
gether, or become greatly diminished in area, this diminution having taken
place during the Tertiary' epoch, and having been continued almost if not
quite up to the present time, thus indicating important physical changes —
either climatic or orographic, or both together — as marking the Tertiary
and Recent periods over a vast area of territory, outside of the State of Cali-
fornia, as well as within it. The difference between the I'esults arrived at in
the Sierra Nevada and those obtained in the region between the Sierra and
the Rocky Mountain range was chiefly this : that in the former case we
had proof of a diminution of precipitation independent of any orographic
changes ; while, in the latter, the phenomena were more complicated, oro-
graphic changes being not .so easily disentangled from climatic ones.

In regard to the period of the extension of the glaciers over the crest
of the range of the Sierra Nevada at a period subsequent to that of former
increased precipitation, we found, on examination, as detailed in the first
chapter of the present volume, that a precisely similar condition of things
took place all over the Cordilleras, north of a certain latitude. The highest
portions of the Rocky Mountains and the very highest summits of the loftiest
ranges of the Great Basin were, at a very recent geological period, covered
by snow, from which were formed glaciers rivalling in magnitude those
of the Sierra itself And as in the last-mentioned range, so in those farther
east, only the most diminished representatives of the ancient glaciers re-
main ; although the peculiar markings and other proofs of their former much
greater extension are preserved in such freshness as to lead to the belief
that they are of extremely recent formation.

All of what has been stated, in regard both to the former glaciation and

158 DISCUSSION OF THE DESICCATION QUESTION.

the desiccation of the region of the Cordilleras, has been found out within a
very recent period, nothing at all having been known of either change of
conditions previous to the commencement of the California Survey in 1860.
But the fact of the former glaciation of portions of the country east of the
Mississippi and about the Great Lakes had been femiliarly known, and much
commented on, twenty or more years before that time. And the same thing
is true of certain parts of Europe : glaciers — both as at present existing
and as occupying a much larger area in former times — have occupied a
large share of the attention of geologists during almost half a century.

To the reader, then, it might have seemed natural that the phenomena
of extinct glaciation in Northeastern North America and in Europe, as well
as in other parts of the world, should have been described in connection with
that which has been said on the same subject in a preceding chapter, in ref-
erence to the region of the Cordilleras. This, however, was not necessary,
or even possible. For, in the first place, the body of facts collected by vari-
ous observers is too large to be brought within such moderate space as the
present volume affords ; and, in the second place, the jaosition of the present
Avriter with regard to the phenomena of extinct glaciation in the Cordilleras
was a peculiar one, rendering it justifiable in him to endeavor to collect
together, for the first time, the principal facts, so that a clear idea might
be had of their scope and bearing; while at the same time attention was
called to some of the remarkable errors into which observers inexperienced
in this department of geological investigation had fallen : this it was neces-
sary to do, since leaving these mistakes uncorrected would have much
increased the difficulty of the subsequent discussion. To a rapid review
of the principal fiicts connected with both extinct and present glaciation
our attention will be naturally directed in the last chapter of the present
work, when, having set forth the principal focts connected with the desicca-
tion of a large portion of the earth, and endeavored to account for the
same, it will have become necessary to show that the former greater exten-
sion of the glaciers over certain regions is not necessarily a condition of
things in conflict with what appears to the writer to have been the course
of events during the geological ages preceding and following the so-called
glacial epoch.

That, on the other hand, the phenomena of desiccation should have been
taken up as manifested in other regions than in the Cordilleras, as has been
done in the preceding chapter, is to be explained by reference to the facts

INTRODUCTORY. 159

that the diminution of precipitation, and the other physical changes con-
nected with the decrease of the water-surfaces and general drying-up of
the earth, are matters of more wide-spread occurrence, and of vastly greater
importance, than is the diminution of the glaciers in certain limited regions.
These ftxcts have never, as the writer thinks, been presented in their con-
nection with each othei'. or examined from the right point of view; while
" glacial geology," on the other hand, may be said with truth to have formed
the staple of the geological journals and text-books during the past few years.

The problem first to be attacked, then, in the prosecution of this investi-
gation is. What means the desiccation which has been shown, beyond doubt,
to have taken place during the later geological ages, and to be continuing
during the historical period ? Is it something which is due to orographic
causes ; or to climatic changes, independent of size, position, and elevation of
the land masses ? Or, on the other hand, has this diminution of moisture
been the result of both climatic and orographic causes acting in concert with
each other; and, if so, is it possible to say what part each of these sets of
causes has taken in bringing about the indicated desiccation ? Still farther,
is it possible to assign a probable cause for such change of climatic con-
ditions as it may have become necessary to assume as having occurred ?
These are the principal questions to which it is proposed that our attention
shall be called in the present chapter.

In Avhat has just been said the writer has not intended to suggest that
the phenomena of desiccation in certain parts of the world have not attracted
much attention, and been the object of more or less discussion. The quo-
tations given in the preceding chapter afford evidence enough that such
remarkable events could not tail to arrest the attention of observers.
What is asserted here is this : that these phenomena have not been consid-
ered in their ensonhle, but rather as simply local manifestations, indepen-
dent of any common cosmic cause ; or as being of a transient nature ; or,
again, as being something entirely exceptional, and not to be brought into
harmony with the ordinary course of nature.

By far the larger number of writers who have discussed the subject of
desiccation have looked upon this remarkable change as something quite by
itself, and as having no connection with precedent changes in the geological
history of the world ! A few, however, have to some extent treated in a
more general way the remarkable phenomena which have been indicated
in the previous chapter : to the views advocated by both these classes of

160 DISCirSSION OF THE DESICCATION QUESTION.

investigators our attention will be given in the present chapter. The views
of those who look upon the climatic change in question as in no wise con-
nected with any orographic or cosmic cause may properly be first examined,
as they can soon be entirely set aside, and removed from the field of our
discussion. This class of authors, which, as has already been stated, embraces
by far the larger portion of those who have written on the subject of des-
iccation, includes all who look u[)on the drying-up of various regions as the
work of man, and not of nature. It is true that these writers often have a
very vivid idea of the magnitude of the change which is going on, in its
effects on the welfare of various peoples ; but they neither connect it with
anything in the geological history of the past, nor do they perceive that it
is something over which man has no control. On the contrary, they believe
tliat man has brought this ruin on himself; and that, if he would only stay
his destroying hand, the land, once fertile and crowded with a prosperous pop-
idation, but now desert and abandoned, would again blossom as a rose, and
again give suppoi't to thriving millions. Of the extent to which this ojain-
ion has become a matter of popular belief, and of the way in which it per-
vades all classes of the community, having impressed itself most deeply on
the minds of scientific observers as well as of popular writers, the follow-
ing extracts, compiled from a variety of sources, will serve to convey some
idea. These quotations are, to a certain extent, analogous in their bearing
Avith those given in the last section of the preceding chapter, but are not
repetitions of the same. There, the dominant idea was, to show how the
reality of the desiccation had impi'essed itself on the minds of travellers and
geographers ; here, the intention is, to show how strongly and positively
various writers have expressed themselves to the effect that it is man's hand
Avhich has wrought the ruin.

The first citation may be from the works of Bernard Palissy, the eminent
potter, who died in 1589.* He says, in answer to his own question, "'And
why thinkest thou that it is so bad a thing thus to cut down the forests ? '
I cannot sufficiently detest such a thing, and do not call it a crime, but a
malediction, and a calamity for all France, for when the forests have all been
cut down, all the arts will necessarily be brought to an end, and the artisans
will have to go and eat grass like Nebuchadnezzar." t

* III tin; Biistille, where he was awaiting execution lor the crime of being a Calvinist.

t CEuvres de Palissy. Paris, 1844, pp. 88, 89. This writer's extreme horror of cutting down trees does not,
however, seem to have been so mucli based on a fear of resultant desiccation as on that of an absolute dearth of
material for use in the arts.

DESICCATION THE WORK OF MAN. 161

Dr. F. Simon}', of Vienna, says : " Of Persia we learn that, although this
country is two and a half times as large as the Austro-Hungarian monarchy,
it has now not more than six or seven millions of inhabitants; and that,
in spite of the thinness of the population, it is a region often devastated by
famine. It is reported that in the j-ears 1871 - 72 between one and a half
and tAvo millions of people died from starvation. And yet this kingdom once
was counted among the mightiest and most flourishing states of Asia, while
the yield of its cultivated land, thanks to its thorough system of irrigation,
was enough to support a population many times as large as that now exist-
ing there. And this has all happened in consequence of the continued destruction of
the forests in the mountains, which noio stand there naked and barren,''* [In Folge
der fortgesetzten Verwiistung der Walder in den Gebirgen, welche gegen-
wartig nackt und diirr dastehen.]

At the International Congress of Land and Forest Culturists, held at
Vienna in September, 1873, instances were cited showing that, "2h consequence
of clearings, there has been a gradual decrease in the depths of the large
streams of all countries."!

On the 27th February, 1856, the subject of the change of climate conse-
quent on the removal of forests was brought before the French Chamber of
Deputies by M. Ladoucette, deputy for the Moselle, who asserted that in the
whole of the Eastern Pyrenees and the Herault the destruction of timber had
been calamitous. The temperature became higher, wells and water-courses
diminished, while the dryness of the climate was greatly increased. Accord-
ing to Professor Laurent, of Nancy, desolation has been brought upon the
nations of the East, — "upon Babylon and Nineveh, Thebes, Memphis, Car-
thage, Palestine and the Troad " bi/ the loss of their forests. t

The number of quotations, to the same effect, and referring to the desic-
cated regions of Asia and the countries bordering on the Mediterranean,
could be multiplied indefinitely. Some additional ones have already been
furnished in the preceding chapter, in cases where the description of
the phenomena, as given by some authors, could not readily be separated
from their theory of the causes of the same. A few more citations will
be made from authors writing in or of America, in order that it may

* III a little work entitled "Schutz dem Walde" — Protection for the Forests — published at Vienna, in
1S78, p. 15.

t Quoted from F. B. Hough's Report upon Forestry. Washington, 1878, p. 292.

t Quoted from Hough's Report, p. 293. The writer has taken the liberty of italicizing a few words in each of
the quotations.

162 DISCUSSION OF THE DESICCATION QUESTION.

not be assumed that this popular belief is in any way limited to the Old
World.

Professor Hartt says : " The wholesale and careless destruction of the
forests on the Brazilian coast, unless put a stop to, will in the end work a
sure ruin to the country. Brazil owes her climate and fitness for agricultural
purposes to her forests, and it is absolutely necessary that they should be
preserved over a very large part of the country, especially on the coast.
The climate of the Bahia has already sufiFei'ed from the destruction of the
forests of the Reconcavo, and the burning over of the plains. But I fear
that Brazil will learn this fact only when it is too late."*

Mr. E. D. Mathews, in describing the lakes near Vacas, in Bolivia, says :
" These are probably parallels, on a small scale, of Lake Titicaca, in the
northwestern corner of Bolivia, or of the lake of Valencia, in Venezuela,
lakes that are known to be decreasing rapidly from extended agriculture,
aided, in the case of Lake Valencia, by denudation of the forests." t

Mr. Wilson Flagg says, in reference to this topic : " The same indiscrimi-
nate felling of woods has rendered many a once fertile region in Europe
barren and uninhabitable, equally among the cold mountains of Norway and
the sunny plains of Brittany." J Farther on, the same writer remarks:
" Nature clothes all parts with trees, and leaves it to man to improve or to
ruin the climate according as he is wise or stupid. Nations in most cases
have ruined it and then sunk into barbarism ; for civilization has never, in
any countr}-, long survived the destruction of its forests."§

Mr. F. B. Hough, chairman of a committee appointed by the American
Association for the Advancement of Science, to report on the cultivation of
timber and the preservation of forests, after the presentation in his report
of a heterogeneous mass of material in regard to climate and forestry, says
under the headina; " What shall we do to be saved ? " — " Such beino; the
consequences of an improvident and indiscriminate clearing off of the timber,
the question naturally arises: 'What shall we do to be saved?' The answer
is plain and obvious : ' Plant trees.' "

It is proper for certain purposes Avhere scientific accuracy is not required
and where it is desirable to draw inferences as to popular opinion, to quote

* Geology and Physical Geography of Brazil. Boston, 1870, p. 321.

+ In "Up the Amazon and Madeira Rivers." London, 1879, p. 245.

t The Woods and By- Ways of New England. Boston, 1872, p. 109.
§ 1. c, p. 142.

POPULAR OPINION IN REGARD TO DESICCATION. 163

fiotn newspapers. In publications of this class hardly a day passes that some
paragraph may not be noticed, either original or going the rounds, as
ordinary newspaper extracts do, — especially in the case of such as contain
incorrect statements of fact, or errors of some other kind, — without contra-
diction, ascribing alterations of climate in various regions to removal of the
forests. These alterations are usually indicated as being wide-spread, and of
a most disastrous nature. One or two quotations of this kind will answer
the purpose of making known the character of the popular impression on the
point in question, as evidenced by the gist of innumerable newspaper para-
graphs. The first is from a leading article in what is usually considered a
highly respectable organ of public opinion, published in a city professing to
be one of culture. " The Arboretum [near Boston] was founded as a scien-
tific establishment in the belief that the information it could gather and
disseminate would add something at least to the world's knowledo;e of the
relation of the forest to man in its climatic, ph^'sical and economic aspects,
and of the methods which, sooner or later, must be adopted to protect our
forest growth, unless the United States is to be allowed to sink to the com-
mercial and social level of tlie deforested countries of the Mediterranean
basin." *

The New York " Nation " thus speaks, in its usual peremptory tone, on
the subject of "our 'protected' forests" : f "Scientific men agree ivith great
unanimity that the preservation of extensive forests is A'ital to the prosperity

of a large part of the country Moreover the prosperity of the West

is an agricultural prosperity directly connected with its forest growth, for
one of the few means of moderating these violent excesses [of climate —
phenomena of excessive winds, rain-fall, and drought having been described in
graphic language in tlie omitted sentences] and keeping up the even distri-
bution of the necessary moisture is by forests In California the de-
struction of the trees has been so reckless that over e:reat tracts of land the
soil, stripped of its natural protection, is burned by the sun and powdered
by the wind into a hopeless desert." %

From the above it will be seen that the prime cause of the desiccation and
the ensuing ruin of various regions is usually considered to be simply the
removal of the forests. There are writers, however, who take a someAvhat

• The Boston Daily Advertiser, number for Kov. 29, 1881.

t In the numher for Jan. 5, 1882. The italics are of the present writer's adding.

X The statement in the last sentence quoted is not true, as a matter of fact, and reference will be again made
to it farther on.

164 DISCUSSION OF THE DESICCATION QUESTION.

different view of the matter. According to them, man in his personality,
and in all his works, is a destructive influence ; and old and long inhabited
countries must, in the nature of things, go to perdition. Sometimes it is
" over-irrigation," at other times " agriculture," in which term, of course,
the removal of the forests may be included. Occasionally we find an author,
even among those of scientific education and of ability, who evidently looks
on civilized man as being, in some mysterious way, antagonistic to nature,
so that intellectual development and multiplication in numbers of any race
carry with them the seeds of future destruction of the nation thus for a
time riding on the wave of prosperity. Farther reference will be made
to this idea in the course of the discussion of the question whether the
changes of climate indicated as having occurred in the various regions speci-
fied can be due to removal of the forests.

Section II. — Is Desiccation the Result of partial or entire Removal of the Forests

htj the Hand of 3fan ?

It seems convenient to di.scuss this question by itself, before proceeding
to take up other more complicated theories which have been advanced by
various authors. If, as the writer believes, it can be clearly shown that man
has not been able to effect a noticeable or important change in the climate
of any region, and that the human race is no Avay responsible for the
changes which have brought and are bringing ruin upon those countries
which, once prosperous, have now sunk into comparative decay, then it
will remove one of the alleged complications, to have this branch of the
inquiry set aside, so as to leave a better opportunity for investigation in
other directions. Not that all can be brought forward at the present stage
of the inquiry which bears on this question ; some points will be better
understood after the general discussion of the phj'sical causes influencing
precipitation, both in amount and distribution, which will come up in the
next section but one. But, without exhausting the subject at present, it
will be a step gained to have acquired a clearer idea of some of the
evidence going to show that the question of desiccation is one essentially
removed from the domain of man's influence ; and that it is incumbent on
the investigator to seek in other directions for some vastly more general and
potent cause of the phenomenon.

It will be desirable, as preparatory or introductory to the present inquiry,

HOW CLIMATE AFFECTS VEGETATION. 165

to say something in regard to the distribution of forests on the earth's sur-
face, and the climatic conditions which accompany and may be assumed to
have influenced this distribution. But a limited amount of investigation is
required in order to have it made clearly apparent to the candid mind that
the character of the flora of any region is most powerfully influenced by
variations of the climate, and especially by changes in the temperature and
the amount of moisture. Summed up in a few words, it may be stated that
extreme cold and extreme dryness are unfavorable to the development of
vegetation. In the case of temperature we see this almost equally Avell
illustrated, whether we journey toward the Polar regions, or rise on the
sides of lofty mountains, the decrease of temperature manifesting itself, in
a most marked degree, by corresponding changes in the vegetation. The
forest trees which are recognized as typical of warm climates disappear;
those characteristic of colder regions make their appearance. These, in
their turn, become more sparsely distributed and dwarfed in size, and finally
give out altogether ; some grasses and flowering plants maintain their hold
up to still higher and colder latitudes ; and finally all these disappear, and
only the lichens remain, of which no land, however far north it may lie, has
ever been found entirely destitute. Of a similar character is the decline of
vegetation as we ascend the slopes of high moimtains. Trees first disap-
pear ; higher up, grasses and flowering plants do the same ; while the lichens
maintain their hold to the last, and often imtil the line of eternal snow is
reached. That these eflfects are mainly due to temperature changes can
hardly be doubted. The disappearance of the trees is coincident with a
diminution of tlie temperature, and is not accompanied by a corresponding
falling off in the amount of precipitation. On the contrary, the giving out
of the arboreal vegetation may and does take place where moisture is abun-
dant, as on the slopes of high mountains between the forest line and the
snow line. The same condition reveals itself most clearly when we consider
carefully the position of the timber-line along the northern edges of the
great land-masses of the northern continent.

But, on the other hand, it is not possible to deny that the presence or
absence of moisture has much to do with the character of the vegetation ;
and no one can doubt that the distribution of forests over the earth's surface
is largely dependent on the position of the areas of greater or less precipi-
tation. A very large rain-fall may coexist with an abundant forest growth ;
and so, as it appears, an abundant arboreal growth may be found in regions

1G6 DISCUSSION OF THE DESICCATION QUESTION.

where the precipitation is comparatively small in amount. Great differences
are found to occur in the rain-fall of forest-covered areas ; so that it seems
hardly possible to say that any quantity of moisture is too great to allow of
the growth of trees, provided that the excess has an opportunity to run off
the surface, and does not stand upon it so as to form swamps or morasses.
At all events, it is a fact that forests are abundantly developed in i-egions
where the rain-fall exceeds 100 inches, and sometimes in those where it
much exceeds this amount. It is also true that there are dense forests in
regions where the total precipitation (in I'ain and melted snow) does not
much exceed twenty inches. Where the amount falls below this last-named
figure, forests do not thrive ; but the grasses usually do so, and often in the
greatest vigor and abundance. An inspection of a rain-chart of the earth,
and a comparison of the position of the rainless and drier areas with that of
the belts or tracts destitute of trees, will be sufficient to show at once that,
in a general way, regions where the rain-fall is deficient, or falls below twenty
or twenty-five inches, are those where trees are least developed ; and also
that a vigorous growth of grasses may be found where the precipitation is
considerably below twenty inches.

It will perhaps surprise the reader to be told, as he may be with truth,
that certainly more than a quarter, and probably more than a third, of the
land surface of the earth belongs to the region in which the grasses and
carices, or a shrubby vegetation, constitute the natural growth, while trees
are almost entirely absent. Asia is the continent on which the amount of
treeless area is proportionally largest; but there are more than two millions
of square miles which may properly be classed in this division in South
America, and more than half that number on our own division of the
continent.

Absolute deserts — that is to say, regions where no vegetation of any kind
covers the surface — are of very much more limited occurrence than are the
steppes above described. Even in localities where the cold is greatest, and
also in those where the heat is most intense and the atmosphere least moist,
some kind of vegetable life may continue to exist, provided the surface be
not a movable one. Thus in the Sahara, which is usually accejDted as a
typical desert region, there are large areas which are covered by a shrubby
vegetation, sparsely distributed, it is true, but not altogether absent. The
really desert regions are those over which movable sands form a heavy cov-
ering, continually shifting their position as urged forward by the driving

CONDITIONS FAVORING THE FORMATION OF DESERTS. 167

Avinds. The same is the case with the desert portion of Arabia ; and these
accumulations of sand seem to have come from the disintegration of sand-
stones, with which the areas in question were oi'iginally underhiin.

Another cause of the formation of really desert areas is the drying up
of lacustrine areas covered by very saline water. In such cases the dry
bottom of the old lake is at first too strongly impregnated with mineral mat-
ter to allow any vegetation to take root and flourish. A long exposure to
atmospheric influences would, in such cases, be required to enable the soil
to get rid of its excess of saltness ; and as such cases of desiccation must
necessarily be confined to regions of small rain-fall, it will be easily under-
stood that such desert areas must, as an ordinary thing, remain unoccupied
by vegetation for an indefinite period.

Since moisture is essential to the vigorous growth of trees, so that very
dry regions are not, as a general rule, covered by forests, it will not be
difficult to understand why treeless areas are usually found in the interior
of tlie great continental masses, as is so well illustrated by the position of
the plains of North America and that of the pampas and llanos of the south-
ern division of the New World. As will be more fidly explained farther on,
the edges of the continents are the regions where the larger portion of the
rain-fall, on the land, takes place. To this rule there are but few exceptions ;
the most striking one is the existence of a rainless belt along a considerable
part of the west coast of South America, a condition of things chiefly depend-
ent on the position of the chain of the Andes, in that region, with reference
to the trade-winds.

Besides excessive dryness and cold, there is another cause which is effec-
tive in preventing a natural growth of forests over certain areas, which are
not unfrequently of very considei-able extent. This condition sometimes
occurs independently of other agencies, so that certain regions remain tree-
less when precipitation is abundant, and the temperature conditions perfectly
fiivorable to the growth of arboreal vegetation. In other places the cause in
question is more or less effective in combination with some other condition
tendincr to brino; about the same result. It is the mechanical texture of the
soil, and especially its fineness, to which allusion is here made. In the
region of the so-called prairies of the ^ILssissippi Valley, especially, there are
very large areas where the rain-fall is ample, but where, over a large portion
of the surface, trees iire wanting, their place being supplied by a vigorous
growth of grasses. Here, moreover, it is evident enough that temperature

168 DISCUSSION OF THE DESICCATION QUESTION.

lias nothing to do with the absence of the forests. Examination, however,
shows that the soil in such regions is of an exceedingly fine texture ; so
much so, that it polishes the tools with which it is cultivated, instead of
scratching them. Careful investigation also reveals the fact that all through
these prairie regions the occasional presence of clumps or belts of trees is
invariably associated with the existence, in such localities, of a coarser vari-
ety of soil. For instance, a grove — as such isolated patches of forest are
usually called — in which the trees are thickly crowded together and flour-
ishing will be seen in the midst of an area of perhaps hundreds of square
miles in extent over which not a single tree is growing. Examination of
such a locality will sliow at once that the grove covers a patch of gravelly
soil, while the surrounding treeless area, which is usually lower and flatter
than the spot occupied by the trees, is covered with the fine prairie soil, the
character of which is so well known at the West, and which lias been repeat-
edly described in the different State geological reports.

In regard to the effect of this peculiar fineness of the soil in preventing
the growth of forests in the " prairie region " of the Mississipj^i Valley, the
writer speaks from careful and long-continued examination of that portion
of the country. That the same conditions hold good in other regions,
and especially over a large ai-ea of the treeless part of the South American
continent, seems, also, hardly to be doubted. There are extensive areas in
that country where the precipitation is certainly more than abundant, and
where the temperature conditions are perfectly favorable, yet where grasses
and various flowering plants and shrubs flourish, to the exclusion of trees.
Here the fineness of the soil seems to be the essential cause of the j^eculiar
character of the vegetation, as it most certainly is in the prairie region of
North America.

The j^eculiar influence of texture of soil in favoring the growth of the
grasses in preference to arboreal vegetation, although advocated many years
ago by the present writer.* has been overlooked by most of the investigators
into problems of this character, and another theorj' has been maintained,
especially by the distinguished German physical geographer Peschel. This
theory is to the effect that it is not the insufficiency of moisture, in such
treeless regions, Avhich prevents the growth of the forests, but its unequal
distribution through the year. This theory was applied by Peschel particu-

* 111 tlie Geology of Iowa, 1858, Vol. I. p. 24. See, also, The American Naturalist for Oetober and November,
1876.

CLIMATIC CONDITIONS IN THE PRAIRIE REGION. 169

larly to the South American pampas and llanos; but was also advocated by
others as the effective cause of the existence of the treeless areas in the
prairie regions of our own countr}'. In the latter case, however, the publica-
tion by the Smithsonian Institution of the statistics of rain-fall in the United
States, as elaborated by Mr. Schott with great care and critical acumen,
rendered it po.ssible to declare with the utmost confidence that there was no
such irregular distribution of the precipitation through the year as had been
taken for granted, without inquiry or investigation, by those promulgating
the theory in question. On the contrary, it appeared certain that the rain-
fall in the prairie States was not only ample in quantity but as regularly
distributed through the year as it was in adjacent heavily wooded regions.
Indeed the existence of forests, hardly surpassed in grandeur by any in the
world, along the slopes of the Sierra Nevada of California, where the precipi-
tation is as irregularly distributed as possible, would, of itself, be sufficient
proof that the theory advocated by Peschel must, to say the least, be looked
on with great suspicion.*

Bearing in mind tlie foregoing remarks as to the vastness of the area of
treeless land on the earth, and the nature of the causes by which this condi-
tion of the surface has been brought about, the reader will be prepared to
examine the question whether it is possible to account for the phenomena
of desiccation, as described in the preceding chapter, by ascribing it to man's
interference with the course of nature, — a theory shown to be so widely
prevalent at the present time.

It must be evident to every one that, at least as a general rule, the tree-
less areas of the earth are such on account of their position with reference
to the distribution of the rain-fall or of temperature, or else on account of
the peculiarities of the soil by which they are covered. In fact, it is not
known that any one has seriously advocated the theory that the steppes of
Asia, for instance, have been made what they are — as to vegetation and
physical character — by the ngency of man. Neither has it occurred to any
one to maintain that forests formerly extended quite to the edge of the sea
along the northern coasts of North America and Europe, and that in conse-

* The pli3'sical-geographical and statistical maps puLlished by tlie Eussian Government, on wliicli the distri-
butiim of tlie forests and the character of the soil of that country are indicated by colors, show the most remark-
able coincidence between the position of the lines bounding the forest-covered area on the south and that of the
region of the so-called " tschornozeni," or black earth, on tlie north. Tliis peculiar variety of soil, as is well
known, is characterized not only by its color, but by its extraordinary fineness, just as is that of the prairie
region of Kovth America.

170 DISCUSSION OF THE DESICCATION QUESTION.

quence of their extermination by man the climate of those regions has be-
come cold, inhospitable, and unfavorable to arboreal growth, as we now find
it to be. No more can it be assumed as jmma facie true, that any part of the
earth's surface, if now destitute of trees, has been rendered so by the hand
of man. Evidence, clear and convincing to that effect, must be furnished, be-
fore credence can be given to statements of this kind. More than this, if
it can be shown that the trees which formerly covered any given area have
been cut down, and that the climate in such a locality, once fiivorable, hns
now become of a character hostile to the prosperity and intellectual develop-
ment of man, it remains still to be proved that it is the removal of the
forests which has been the effective agent in bringing about this changed
condition of things.

If it bo true that the desiccation of certain regions, which seem on trust-
worthy evidence, as set forth in the preceding pages, to have become drier
during the historic period, was begun long before man could have been in
existence to interfere with nature's work, then we shall have strong reason
to infer that Avhat was begun Avithout the interference of man, and continued
for an indefinite period without it, may be still going on in the same way,
and that we are only the witnesses of the continuous working of an agency
which would have remained effective even if the earth had never become
inhabited by man or animal.

That the drying-up of the Central Asiatic and the Cordilleran regions is a
phenomenon Aviiich was begun long before man could have interfered with
the course of nature, seems evident from the facts which have been set forth
in the preceding chapter. Whether we consider the diminution of the Ter-
tiary rivers of California to their present comparatively insignificant size,
the dwindling away of the lacustrine areas of the Great Basin, or the similar
condition of things shown to have been begun in the heart of the Asiatic
Continent at least as early as the Tertiary period, we are forced to admit
that we have to do with a phenomenon as far beyond man in the length of
time it has been in operation as it is beyond the scope of his powers from
the point of view of its magnitude.

No one has ever suggested that the drying-up of the region of the
Cordilleras was due to the action of man ; neither has a similar claim been
urged, to any considerable extent, with regard to the vast area of Central
Asia where the phenomena of desiccation present themselves in such a strik-
ing manner. Neither has it been suggested with reference to the great

SUPPOSED INFLUENCE OF FOEESTS ON RAIN-FALL. 171

diminution of the lakes of Central Africa described by Livingstone. It is
almost exclusively in reference to the present condition of the region border-
ing the Mediterranean that the theory in question has been urged, and it is
from their hapless fate that the inhabitants of other regions, not yet suffer-
ino- in like manner, are warned. The reasons of this will be obvious enou2:h.
The intimate connection of that region with the development of the human
intellect renders ever^-thing connected with its past history and present con-
dition a matter of profound interest to other nations who have received from
that quarter the light of civilization. Few care enough for the past or
present condition of Equatorial Africa to investigate the changes of climate
it may have undergone ; and certainly historical research on such a point
would there be quite unavailing. The same may be said of the southern por-
tion of Central Africa, of Central South America, and of most other areas
where the phenomena of desiccation have been displayed on a large scale.
It is only around the Mediterranean, and in the region to the east of it, that
we can ever expect any historic light of importance on this question. Some
special inquiry ought therefore to be made from a historical point of view
into the evidence which those countries are able to furnish bearing on the
problem before us.

It might be supposed, from the positive manner in wdiich it is stated
by man}' that the cutting down of the forests in the countries bordering
on the Mediterranean has brought them to their present condition, that
historic records showed that that whole region was once heavily covered
b}' a growth of trees. This is by no means the case : it cannot be proved
from the works of ancient authors that those countries have ever, within the
historic period, been even moderately well provided with forests. The re-
mains of petrified trees, which are found over portions of this area, belong
to a prehistoric period, and probably to the later Tertiary. No representa-
tions of the scenery found among the monuments of Eg3'pt give us authority
for placing that country among the forest-covered regions.

Mr. Burton evidently believes that, in the case of the region explored by
him with special reference to its ancient mining work (the Land of Midian), —
where he thinks that mining operations were carried on up to the seventh
century of our era, — the necessities of such work demanded the use of a large
amount of fuel, and that this would prove that the country was formerly
well clothed with forests. This, however, need not have been the case, as
may be illustrated by reference to what the writer has himself observed in

172 •■ DISCUSSION OF THE DESICCATION QUESTION.

the region bordering the eastern slope of the Sierra Nevada. Here is a
country of small rain-fall, too dry ever to be thickly inhabited, and which at
first sight, when it began to be settled by a population called thither by the
richness of its silver-mines, would have been described as a ti'eeless region.
Nevertheless, for several years after the mines on the Comstock Lode, at
Virginia City, were opened, and when the very extensive mining and metal-
lurgical operations carried on there demanded a very large amount of wood,
this was mainly furnished by the adjacent mountains. The seemingly tree-
less country did yield, for some time, from the depths of its almost inac-
cessible gorges and canons, a very large supply of fuel. Such we may
imagine to have been the case in the Land of Midian, if it can be proved
that the kind of mining operations carried on there did really demand any
considerable amount of wood, which, as would appear from the nature of
the metal obtained, — gold, namely, — is not so certain. At all events, we
have in the experience of the Nevada silver-mining region evidence bearing
on the point in question. That country has, within twenty years, and under
the observation of the present writer, been thoroughly stripped of its scanty
forests. That this, however, has in any way changed the character of the
climate, or rendered the region less habitable than it Avas before, is not evi-
dent from any facts reported or observed. That fuel has had to be brought
from greater and greater distances to the various smelting and metallurgical
works, is plain enough ; and that, in consequence, its price must have greatly
risen, when other means or facilities of supply were not forthcoming, is also
not to be denied. This, however, has no connection with anything claimed
as the result, in the Mediterranean region, of disforesting the country. No
doubt if rich mines could be proved to be still existing in the Land of Mid-
ian, fuel would be got to them in some way ; and if rich enough, they would
be worked with success.

Statements like that quoted on a preceding page, to the effect that the
climate of portions of the Pacific Coast has been changed for the Morse " by
the reckless destruction of the trees," * are entirely without foundation in
fact. They well illustrate, however, the facility with which evidence is man-
iifactured to support any theory which may, for some reason, have secured a
hold on the popular mind. The so-called Desert of Southern California — the
only portion of the State where the " ground is burned by the sun and pow-
dered by the wind into a hopeless desert" — was not long since covered by

* See, ant::, ji. 163.

HAS NEW ENGLAND BECOME A DESERT 1 173

lakes 01' by an inland sea;* and of course it can nevei' have been disforested.
All about the Bay of San Francisco the removal of the timber has gone on,
within the past few ^-ears, with the greatest rapiditj' ; more so than anywhere
else in the State. But there is no statistical proof that the rain-fall in that
region has been diminished since the occupation of it by an English-speaking
people. On the other hand, it is believed that there is no portion of this
continent which is considered by its inhabitants to have so well founded a
claim to be recognized as an earthly pai\adise.

An excellent opportunity appears to the writer to have been offered in
New England for throwing light on the question whether disforesting a
country does really change the character of its climate or materially di-
minish its rain-fall. There is no doubt that New Ensrland was, not loner
since, a country well covered Avith a forest growth. That it was such w'hen
its settlement by the whites began, 250 years ago, is a generally admitted
fact. The aboriginal inhabitants had not in any perceptible degree taken
from it, during their occupancy, its character as a great forest.f For the
purposes, however, of the present illustration, attention will be called to
the southwestern portion of the region in question, or the area included
within the States of Massachusetts, Rhode Island, and Connecticut, and the
southern half of Vermont and New Hampshire, embracing in all about
25,000 square miles.

At the present time the area designated has been so far disforested that
nearly all of it is placed on Professor Brewer's " Map showing in five degrees
of density the distribution of woodland within the Territory of the United
States " t in the lowest of those grades, having thus been apparently reduced
from the highest to almost the.lowest condition, as respects the abundance of
its timber, since the settlement of the country by the whites.

That a large part of this destruction of the forests has taken place within
the past fifty years, and since railroads were generally introduced, seems
to the writer a not unreasonable statement. His own recollections would

* As mentioned on pp. 104, 105.

t Sep, on this point, Palfrey's Histoiy of New England, Vol. I. p. 16. He says : "The woods were so vast
that the early writers describe them as covering the country," — quoting, in sujjport of this statement, from
Higginsou, in Mass. Hist. Coll. I. 117 : " Though all the country he, as it were, a thick wood in general, yet in
divers places there is much ground cleared by the Indians." Also from Josselyn's New England's Rarities : " The
country generally is .... extremely overgi-own with wood;" and from Early Records of Charlestown: "An
uncouth wilderness full of timber." Here we have the word "timber," which is in common use all over the
United States instead of forest.

J In Walker's "Statistical Atlas of the United States."

174 DISCUSSION OF THE DESICCATION QUESTION.

justify him in stating, at least, that the change brought about within forty
or fifty years in regard to the comparative areas of forestrcovered and
nnwooded country in Southern New Englani] is very great. This period
of forty or fifty years is insisted on, because the observations for rain-fall
taken in this region go back just about as for as that. If, then, disforesting
a country is followed by a marked decrease of the precipitation in the region
cleared of its trees, we ought to find some evidence of the foct in the case
of Southern New England. The statistics, as given by Mr. Schott for numer-
ous stations Avithin the area specified, do not, however, in the least indicate
any diminution * of the rain-full during the past half-century ; on the con-
trary, the conclusion is reached that, for the Atlantic sea-board, fiom Maine
to Virginia — this area forming Group!, of Mr. Schott's division of the whole
country into climatologically allied regions — an increase of raiu, on the
average, since 1835, is "distinctly indicated." A similar condition of things
is reported for the adjacent region of New York, where also, as well as in
Southern New England, very extensive clearings have been made during
the past fifty years.

These results are more valuable, inasmuch as the average annual rain-fall
within the region in question is not very large, and it could not be consider-
ably diminished without disastrous effects. The precipitation at Providence,
for instance, from which place we have one of the longest and best series of
observations which has been made in New England, the average from 1832
to 1867 Avas 41.51 inches, with a prett}' regular distribution, the amount
never falling below thirt}', or rising above fifty-five, inches. A diminution
of this amount to the extent of one third would undoubtedly have very
serious consequences, while taking off ten or fifteen inches from the rain-fall
of a region where the annual average was over a hundred inches would prob-
ably not be perceived at all, except as instrumentally recorded.

Under any circumstances, our own country does not furnish, in any part
of its vast area, any support to the theory that removing the forests brings
about a condition of barrenness and desolation. No one would say that any
portion of New England had become barren or desolate, or had been ren-
dered any less capable of supporting a dense population than it was at the
time of the arrival of the first English-speaking people upon its shores.

It has been supposed by some that the idea of a diminished rain-fall as a

* The observations used by ilr. Schott go back, in the case of one station, to the year 1804 ; records, how-
ever, soon began to be kept at additional points, and the number increased rapidly from 1830 on.

HAS THE CLIMATE OF SALT LAKE VALLEY BEEN CHANGED ] 175

necessary consequence of removing the forests had found support in certain
alleged foots going to prove the converse of that theory. If it could be
shown that causing trees to grow in comparatively rainless regions had
brought about a more abundant precipitation, then it would be allowable to
infer that their destruction would have just the opposite effect. In regard
to this point, however, there is in reality but little chance of obtaining valu-
able evidence, for — thus far, at least — no attempt has been made on any
very large scale to reproduce forests artificially where they are once sup-
posed to have existed, and where now they are certainly absent. To show
the ease with which evidence of the kind desired for the support of the
theory in question can be manufactured, reference may be made to Eg^q^t,
a country in regard to which it is always being asserted in popular works of
travel, and especially in the new'spapers, that its climate had been decidedly
changed, of late years, by the increased cultivation of trees. The statements
to this effect do not, however, at all bear examination. The statistics are
confessedly imperfect; but, as far as they do go, they prove, if anything, a
deterioration of the climate, since the beginning of the present century,
rather than a gain in the amount of moisture. Captain Burton says, in refer-
ence to this point : " An idea demanding correction is the popular fancy
tliat the frequency and quantity of rain in Eg3'pt have increased of late
years by the planting of trees. Clot-Bey and M. Jomard declared that,
despite the vigorous measures of Mohammed Ali Pasha, who alone laid
down three millions of mulberries, the fall measured what it did forty ^-ears
before. The Meteorological Tables, for the three years of French occupa-
tion, drawn up by M. Coutelle, compared with the recent observations of
Mr. Destoviches, show no sensible variation. Between a. d. 1708 and 1800,
the rainy days averaged fifteen to sixteen ; while, during the five yeai'S
between 1835 and 1839, it diminished to twelve - thirteen. The Abassiyyeh
Observatory registered (1871) nine rainy days at Cairo, with a total of 9.08
hours ; and thus it gave a rain-ftdl inferior to that witnessed by the begin-
ning of the century."*

Similar statements have been made repeatedly in regard to changes of
climate in Salt Lake Valley, Utah, said to have been brought about by the
cultivation of tracts bordering on and in the vicinity of that lake. Mr.
IIougli,t after describing the irrigation works in Utah, which had, as he says,

* R. F. Burton. The Gold Jliiies of Jliilian. London, 1878, p. 26.

t In the Eeiiort to Congress on the Cultivation of Timber, etc., already quoted, p. 92.

176 DISCUSSION OF THE DESICCATION QUESTION.

extended over 127,798 acres (somewhat less than one four-hundredth part
of the whole area of that Territory), says : " All observers agree that the
climate is improving under the increasing breadth of vegetation which this

system of cultivation has created The industrious Mormons have a

right to expect that, as the breadth of cultivation extends, ,the rains will
increase in the same ratio ; that the air will become more humid as trees are
planted, and that a self-sustaining amount of rain-fall may in time be ob-
tained." It is not denied that Great Siilt Lake began to rise about the
year 1866, and continued to do so for several years after that time. This
confirms the thoroughly well authorized deductions drawn fiom a variety
of facts observed all through the Great Basin, namely, that the desiccation of
the region has not been absolutely uniform in character; but that, on the
other hand, it has proceeded with more or less gentle oscillations, the result
of which, on the whole, has been, that the lake now stands several hundred
feet lower than it has done since there has been any orographic change in
the region.* We shall have abundant occasion, farther on, to point out facts
indicating, in the most unmistakable manner, that the forces regulating
evaporation on the earth are so delicately balanced that fluctuations of these,
too small to be registered with our ordinary instruments, produce results
which are decidedly well-marked in their effect on climate. But these fluctu-
ations, such as tlio.se of the Great Basin Lakes within the past few years,
do not interfere with the general result, which slowly but surely maintains
itself in spite of them.

The reason why Salt Lake has, on the whole, greatly diminished in area
within the recent geological period is, that evaporation more than counter-
balance