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THE ICE AGE 
IN NORTH AMERICA 


AND ITS BEARINGS UPON THE 
ANTIQUITY OF MAN 


SY. 


G. FREDERICK WRIGHT, D.D., LL.D., res.a 


Late assistant on the Pennsylvania and United States Geological Surveys 
Author of ‘‘Logic of Christian Evidences,”’ ‘‘Greenland Ice Fields,”’ ‘‘ Asiatic Russia,” etc. 


peed etre? 32 ey 
Fifth edition with many new maps ‘pnd iliustrations, enlarged 4 
and rewritten to incorporate the facts that bring i$ ap 40 date,» ee 
with chapters on Lake Agassiz and the, Preiysbl>> Cause’ "all Bed eae 
Glaciation, by Warren Upham, Sc.D., F.G.8.A.) lace Assistant?” 
on the Geological Surveys of New Harapshire, Minnesota, the 
United States, and Canada. 


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OBERLIN, OHIO 


BIBLIOTHECA SACRA COMPANY 
1911 


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LOsed 


BIBLIOTHECA SACRA C 


TO 
ELISHA GRAY 
_ CHEVALIER DE LA LEGION D’HONNEUR 
” INVENTOR OF THE HARMONIC TELEGRAPH, THE TELEPHONE 
% AND THE TELAUTOGRAPH 
WHOSE INTELLIGENT INTEREST IN GLACIAL GEOLOGY 


AND WHOSE GENEROUS ‘APPRECIATION OF MY WORK 


’ é 
_ 


HAVE BEEN A CONSTANT INSPIRATION 


ahs 


THIS VOLUME IS AFFECTIONATELY DEDICATED 


oe? 


PREFACE TO THE FIFTH EDITION. 


The twenty years which have elapsed since the publica- 
tion of the first edition have been exceedingly fruitful in 
glacial investigations, as will be seen by consulting the bibliog- 
raphy at the end of this volume. Nevertheless, as premised 
in the preface to the first edition, these later investigations 
have not seriously affected the main theories adopted twenty 
years ago; but “pertain mainly to the details of the subject.” 

In the present revision the new material added is especially 
abundant only upon a few subjects. Many existing glaciers 
have been discovered in the Rocky Mountain system in the 
United States and Canada—a region which was scarcely 
touched by explorers until the close of the last century. 
Explorations have also greatly extended our knowledge of 
Alaskan glaciers while the changes in the Muir Glacier have 
been so enormous as to be really startling, fully sustaining 
the theoretical conclusions which I had drawn from my stud- 
ies of the glacier in 1886. Much new material, also, has 
accumulated concerning the glaciers of Greenland, Central 
Asia, and the Antarctic Continent. 

As to the extent of the continental glaciers of the Pleisto- 
cene period, there has been little additional information 
since the publication of the first edition. Among the most 
important additions has been the rectification of the glacial 
boundary across New Jersey and Pennsylvania, where the 
“fringe,” or ‘‘attenuated border,” imperfectly apprehended 
by Lewis and Wright, has been carefully traced by Professor 


vi PREFACE TO FIFTH EDITION. 


E. H. Williams from the Atlantic Ocean to-Ohio and found to 
be from twenty to thirty miles south of their. terminal moraine. ~ 

The facts relating to this border, brought out by Professor 
Williams, have a most important bearing upon the discus- 
sion both of the cause and of the date of the Pleistocene glacial 
epoch. 

There has also been a great accumulation of evidence, 
collected pretty largely by Mr. Frank Leverett and the geolo- 
gists of.lowa, Minnesota, Dakota, and Canada, concerning 
the episodes of the Pleistocene glacial epoch, leading to the 
division into the Kansan, Illinoisan, Iowan, and Wisconsin 
periods of advance and retreat. The relative length of time 
occupied by these episodes is still a most interesting subject of 
investigation. | 

The question of the date of the Pleistocene glacial epochis 
still a subject of hot discussion, but a great accumulation of 
facts, relating to post-glacial erosion and sedimentation, are 
rapidly establishing a very moderate glacial chronology. 

Likewise a great accumulation of facts is limiting the the- 
ories concerning the cause of glaciation to changes in land 
elevation and in the direction of oceanic currents. The chap- 
ters upon the date and the cause of the epoch have been 
greatly enlarged and rewritten. 

The final chapters upon the discovery of human relics in 
deposits connected with the Glacial epoch in North America 
have also been thoroughly revised and enlarged, to take into 
consideration the more recent discoveries of facts bearing 
both for and against man’s existence here in glacial times. 


G. FREDERICK WRIGHT. 
OBERLIN, OuI0, December 22, 1910. 


PREFACE TO FIRST EDITION, 


Tue present treatise is the outcome of special studies 
upon glacial phenomena begun in the summer of 1874, in 
the eastern part of Massachusetts, the results of which 
were published in a communication to the Boston Society 
of Natural History in December, 1876. These first studies 
pertained to the origin of the gravel-ridges described in 
this volume under the name of “kames.” Fortunately, 
in the preparation of that paper, I was favored with an 
interview with Mr. Clarence King, who then gave me the 
information referred to in the following pages, concerning 
the terminal moraine south of New England, which has 
been so fruitful of suggestion to other investigators as 
well as to myself. Since that time the subject has never 
been out of mind, and my summer months have all been 
devoted, under favorable conditions, to the collection of 
field notes regarding it, and so it has seemed to others, as 
well as to myself, appropriate that I should endeavor to 
tring the facts within the reach of the general public. 

After having become, during the four following sea- 
sons, familiar with the glacial phenomena over the larger 
part of New England, I was invited by Professor Lesley 
to survey, in company with the late Professor H. Carvill 
Lewis, the boundary of the glaciated area across Pennsyl- 


vill PREFACE TO FIRST EDITION, 


vania (our report constitutes Vol. Z of the Second Geologi- 
cal Survey of that State). The summers of 1882 and 1883 
were spent under the auspices of the Western Reserve His- 
torical Society of Cleveland, Ohio (whose secretary, Judge 
C. C. Baldwin, had the sagacity to recognize, at that eariy 
time in the investigations, the historical bearing of the 
work), in continuing the survey across Ohio, Kentucky, and 
Indiana (see my report to that society, 1884, and an article 
in the “ American Journal of Science,” July, 1883). Dur- 
ing the summers of 1884 and 1885 I was employed, as a 
member of the United States Geological Survey, in tracing 
the boundary across IJlinois, and in reviewing the field in 
Ohio and western Pennsylvania. The report of this work 
has not yet been made public, but permission to use the 
facts has been generously granted by the director of the 
survey, Major J. W. Powell. The summer of 1886 was 
spent in Washington Territory, and upon the Muir Glacier 
in Alaska. The two following ‘seasons were occupied in 
further exploration of Ohio, Dakota, and other portions of 
the Northwest. Thus I have personally been over a large 
part of the field containing the wonderful array of facts of 
which I am now permitted to write. 

In the autumn of 1887 I was invited to give a course 
of lectures upon the Ice Age in North America before the 
Lowell Institute in Boston, and in the following year be- 
fore the Peabody Institute in Baltimore. For the informa- 
tion of the audiences who heard those courses of lectures it 
is proper to say that the present treatise incorporates all 
the facts then presented, though in a different form. The 
volume covers, however, a much wider field than the lect- 
ures, and is more ample in its treatment of all the topics. 

But it is not to be supposed that a single person can 


PREFACE TO FIRST EDITION. 1X 


adequately survey so large a field. The writer is but one 
of many investigators who have been busily engaged for 
the past fifteen years (to say nothing of what had been 
previously accomplished) in collecting facts concerning the 
Glacial period in this country. My endeavor has been to 
make the present volume a pretty complete digest of all 
these investigations, and in carrying out that aim I have 
had the generous assistance of the great array of careful 
and eminent observers who have turned their attention to 
the subject. So far as possible I have, by their permission, 
given their results in their own language, and with due 
eredit. I hereby take occasion to express my obligations 
for the help which they have, one and all, so courteously 
rendered. 

The numerous maps accompanying the text have been 
compiled from the latest data, as indicated in the abundant 
foot-notes scattered throughout the volume. These render 
it unnecessary to make here any more specific acknowl- 
edgment of authorities. 

The volume is committed to the public in the belief 
that it will meet a widely felt want. The accumulation 
of facts for the past decade has been so rapid, and from so 
many sources, that few persons have been able to keep 
themselves informed of the progress made. And so great 
has this progress been that we may now safely assume that 
future discussions will pertain mainly to the details of the 
subject. We now know, from actual observation, the limits 
and prominent characteristics of the glaciated area on this 
continent. The Glacial age of North America is no longer 
a theory, but a well-defined and established fact. 

It will become apparent also that, though the title of 
the book is the “Ice Age in North America,” it is really 


x PREFACE TO FIRST EDITION. 


a treatise on the whole subject of the Glacial period; for, 
with the vast field open for investigation on this continent 
and the amount of attention recently given to its explo- 
ration, North America is now by far the most favorable 
place from which to approach the study of ice-action and 
ice periods. | 

The last chapters of the volume treat of man’s relation 
to the Ice age on this continent; and I need not disguise 
the fact that the bearing of the discoveries upon this ques- 
tion has all along given zest to my investigations. The 
facts with regard to this subject also are now so far in 
hand that they can be properly discussed in a treatise de- 
signed in part for the general public. 

While presenting as fully as is necessary the evidence of 
man’s occupancy of the continent during the great Ice age, 
and while accepting this as necessitating a considerable 
extension of man’s antiquity as usually estimated, I have 
not felt called upon in the present discussion to say any- 
thing about the method of reconciling this fact with the 
chronology of the human race supposed to be given in the 
sacred Scriptures; for I have elsewhere (in my “ Studies 
in Science and Religion,” W. F. Draper, Andover, 1882, 
and “Divine Authority of the Bible,” Congregational Pub- 
lication Society, Boston, 1884) said all that it seems at 
present necessary for me to say upon this point. I will 
only remark here that I see no reason why these views 
should seriously disturb the religious faith of any believer 
in the inspiration of the Bible. At all events, it is incum- 
bent on us to welcome the truth, from whatever source it 


may come. 


G. FRreperick WriGcHT. 
OBERLIN, On10, April 15, 1889. 


CONTENTS 


CHAPTER I. 


PAGE 
Wuat Is A GLACIER? : : 2 a : : 1-12 


The Appearance of ice deceptive, 1 ; Discovery of its Real a 2 ; Motionofa 
Glacier, 2 ; Effect of Friction, 3 ; Cause of the Moticn, 4 ; Plasticity of fos 5 ; Rela- 
tion of Snow to Ice,6 ; Structure of a Glacier,7 ; Veins, 7 ; Fissures, 8 ;Ice-Pillars, 
10 ; Terminal Moraines, 10 ; Kames, 11 ; Glacial Scratches and Groovings, 12. 


CHAPTER II. 


EXxIsTING GLACIERS ON THE Paciric Coast . : : 13-39 


In Southern California, 13 ; in Northern California: Mount Shasta, 15 ; in Oregon, 
19 ; in Washington Territory: Mount Tacoma, 19 ; British Columbiaand Alaska, 
23 ; on the Stickeen River, 25 ; in Taku Inlet: Norris Glacier, 27; in Lynn Canal: 
Davidson Glacier, 27 ; north of Cross Sound, 29; on Mt. St. Elias, 30 ; in 
Yakutat Bay, 30 ;north of the Alaskan Peninsula, 36. 


CHAPTER III. 


A Monts WITH THE MuiIR GLACIER 2 d : : 40-74 


Purposes of the Expedition, 40 ; Facilities for Observation, 41 ; Description of 
Glacier Bay and its Surroundings, 41 ; Muir Inlet, 43 ; Dimensions of the Muir 
Glacier, 43 ; Various Characteristics, 47 ; Moraines, 49 ; Indirect Evidences of 
Motion, 50; Formation of Icebergs, 51 ; Subglacial Streams, 51 ; Direct Measure- 
mentof Velocity, 52; Retreat of the Ice-front, 55; Former Extensionof the Glacier, 
59 ;a Buried Forest, 61 ; Kamesand Kettle-holes, 66 ; Transportation and Waste 
by Water, 67 ; Temperature in August, 68 ; Floraof the Vicinity, 69 ; H. F. Reid’s 
Measurements, 71 ; F. E. and C. W. Wright’s Observations, 72. 


CHAPTER IV. 


GLACIERS OF GREENLAND ‘ : : 75-102 


Extent of Greenland, 75 ; Nordenskiéld’s poeta rt 75 ; Amount of Coast Line 
already explored, 77 ; Number of First-class Glaciers in Danish Greenland, 78 ; 
Movementof Ice inthem, 78 ; Nunataks, 71 ; Former Extension oftheIce, 79 ; 
Helland’s Observations, 80 ; Whymper’s Description, 83 ; Explorations of Kane 
and Hayes, 86 ; Humboldt Glacier, 92 ; Glaciers on the Eastern Coast of Green- 
land, 97 ; Nansen’s Expedition, 98 ; Erichsen’s Expedition, 99 ; Holst’s Obser- 
vations on Frederickshaab Glacier, 100. 


xi 


X11 CONTENTS. 


CHAPTER V. PAGE 


GLACIERS IN OTHER PaRTS OF THE WORLD . : * 104-121 
In the Alps, 104 ;in Scandinavia, 106 ;in Spitzbergen, Franz-Josef Land, and Ice- 
land, 107 ; in Asia, 107 ; in South America, 108 ; Darwin’s Account, 109 ; in New 
Zealand, 112 ; on the Antarctic Continent, 112 ; Icebergs of the Southern Ocean, 

115 ; Croll’s Inferences from the Size of these Bergs, 118 ; Shackleton’s Expedition 
to the Antarctic, 120. 


CHAPTER VI. 


SIGNS OF GLACIATION. ; k = : 122-133 


Introductory Remarks, 122 ; Groovesand Scratches, 123 ; Sir Charles Lyell’s Ob- 
servations in Nova Scotia, 126 ; the Ground Moraine, or ‘‘ Till,”’ 129 ; Cause of its 
being unstratified, 130 ; Sifting Power of Water, 131; Distribution of Bowl- 
ders, 132. 


CHAPTER VII. 


BOUNDARY OF THE GLACIATED AREA IN Norts AmeERiIcA 134-193 


Confluent Character of the Ice-sheet, 134 ; Progress of Discovery, 134 ; Elements 
determining the Amount of Glacial Deposition, 135 ; Counteracting Influence of 
Subglacial Streams, 136 ; Influences determining the Amount of Marginal De- 
posits, 137 ; south of New England, 137 ; Interior Marginal Deposits, 139 ; 
Long Island a Moraine, 140 ; Marginal Deposits across New Jersey, 140 ; Rela- 
tion of Kettle-holes to the Moraines, 143 ; Marginal Deposits in Eastern Pennsyl- 
vania, 144 ; Western New York and Pennsylvania, 149. 


CHAPTER VII (contTINvUED). 


THE ATTENUATED BORDER . i ‘ s 2 3 151-166 


Line of, 153 ; Lake Williams, 153 ; Character of Materialin, 154 ; Lake Lesley, 156 ; 
Lake Allegheny, 158 ; Changes of Land-level, 160 ; Valleys of the Allegheny 
River, Conewango Creek, and Ohio River, 161. 


CHAPTER VII (conciupEp). 


THE GuactIAL BouNDARY WEST OF PENNSYLVANIA ; 167-193 
Marginal Deposits through Ohio, 167 ; Extension of the Ice into Kentucky, 170 ; 
Course of the Boundary in Indiana and Illinois, 170 ; Boundary west of the Miss- 
issippi, 172 ; west of the Rocky Mountains, 176 ; Ancient Glaciers in Southern 
California, 179; Glacial Boundary north of Puget Sound, 183 ; near the Head- 
waters of the Yukon, 190; Summary of Facts regarding the Pacific Coast, 190. 


CHAPTER VIII. . 


Depts or IcE DURING THE GLACIAL PERIOD : : 194-202 


Means of Estimating it, 194 ; Mountain Summits covered in New England, New 
York, and Pennsylvania, 194 ; Depth estimated from the Distance moved, 199 ; 
Slope of a Glacier, 201. 


CONTENTS. xili 


CHAPTER IX. PAGE 


TERMINAL MORAINES x : 203-225 


Indefiniteness of the Term, 203 ; Prominence of the Moraine south of New Eng- 
land, 204 ; Details respecting the Kettle-holes in this Part of the Moraine, 205 ; 
Submerged Portions of the Moraine, 206 ; Moraines of the Middle States, 207 ; 
President Chamberlin on the Moraines west of the Alleghanies, 207 ; Gilbert on 
the Moraines of the Maumee Valley, 207 ; the Kettle Moraine of Wisconsin, 211 ; 
Battle of the Glaciers in Minnesota and Wisconsin, 212 ; Moraines in Dakota,214 ; 
in Central British America, 217 ; Later Moraines in the White Mountains, 221 ; 
on the Sierra Nevada and Cascade Mountains, 222 ; Moraines of the Wisconsin 
Episode, 222 ; Ilinoisan Deposits, 223 ; Iowan Deposits, 223 ; Kansas Deposits, 
224 ; the Aftonian Episode, 224. 


CHAPTER X. 


GLACIAL EROSION AND TRANSPORTATION i : ; 226-280 


Erosive Action of Ice compared with that of Running Water, 226 ; Chemical 
Action of Water, 229 ; Danger of exaggerating the Erosive Action of Ice, 230; 
Glacial Erosion least near the Margin, 233 ; Analogy between the Glacial Front 
and Breakers in the Ocean, 234 ; Transportation of Bowlders on the Surface of a 
Glacier, 236 ; Details respecting, in Southern New England, 237 ; in Richmond, 
Mass., 239 ; in New Jersey and Pennsylvania, 241 ; in Ohio, 242; in Southern In- 
diana and Illinois, 243 ; in lowa and Dakota, 248 ;in British America, 244 ; Ele- 
vation of Bowlders in the Ice, 246 ; Explanation of, 248 ; Erosion of Subglacial 
Streams, 254 ; Erosion estimated by the Amount of Till, 257 ; Attemptsat Direct 
Measurement of Glacial Erosion near the Delaware Water-Gap, 260 ; affected by 
Preglacial Disintegration, 261 ; Evidence of, near Western End of Lake Erie, 262; 
in the Sierra Nevada, 267 ; Summary, 279. 


CHAPTER XI. 


DRUMLINS seater : : 4 : ‘ , : 281-297 


Definition, 281 ; those in the Vicinity of Boston Enumerated, 281; Mr. Upham’s 
Description, 282 ; Series of, in Rockingham County, N. H., and Essex County, 
Mass., 284 ; Occurrence of, in the Interior of the Country, 285 ; Theory of their 
Formation, 287; Irregularities of Glacial Erosion and Deposition, 294. 


CHAPTER Xfi. 


PREGLACIAL DRAINAGE . : , 298-312 


Length of Preglacial Time, 298 ; extent of melts ileal 299 ; the Trough of 
the Ohio preglacial, 300 ; Other Preglacial Valleys, 302 ; Preglacial Drainage of the 
Great Lakes, 304 ; Preglacial Drainage of the Upper Allegheny River into Lake 
Erie, 307. 


CHAPTER XIII. 


DRAINAGE OF THE GLACIAL PERIOD 2 7 : 313-337 


Obstruction of Ice-barriers across the Red River of the Sad the St. Lawrence, 
and the Mohawk, 313 ; Closing Floods of the Glacial Period, 314 ; Terraces pro- 
duced by these Floods in the Trough of the Mississippi; in the Minnesota, 315 ; 


XiV CONTENTS. 


PAGE 
inthe Northern Tributaries of the Ohio, 323 ; in the Streams of Northern Pennsyl- 
vania, 325 ; Material composing the Glacial Terraces, 325 ; such Terraces absent 
from Streams wholly in the Unglaciated Region, 325 ; Terraces on the Ohio, 327 ; 
on Beaver Creek, Pa., 328 ; on the Delaware, 289 ; Relation of Pot-holes in Graf- 
ton, N. H., to Glacial Drainage, 330 ; Similar Phenomena in Lackawanna County, 
Pa., 331 ; Remarkable Evidence of Abnormal Glacial Drainage in Dakota, 332 ; 
Marginal Drainage in the Northwest, 334. 


CHAPTER XIV. 


KAMES. : ; : ; : ’ ; ‘ 339-354 


In Andover, Mass., 339 ; Definitions, 339 ; Geikie’s Description, 339 ; Relations of 
Kames to Terminal Moraines, 340 ; Origin of, 341 ; indicate Lines of Temporary 
Glacial Drainage, 342 ; Lines of, in New England enumerated, 343 ; Questions 
respecting, inthe Connecticut River Valley,345 ; Possible Extent of Glacial Floods 
in this Valley, 346 ; Relation of Sandy Plains to Kames, 348 ; Existence of Kames 
foretold, 349 ; Overwash Gravel limited in Amount, 350 ; Abnormal Relation of 
Kames to the Slope, 351 ; Summary, 353. 


CHAPTER XV. 


GuactiaAL Dams, LAKES, AND WATERFALLS : ’ 355-406 


Rock Basins eroded by Glaciers, 355 ; Theory of the Great Lakes, 356 ; Two 
Classes of Glacial Dams, 359 ; Kettle-holes, 359 ; Relation of, to Peat-bogs and to 
Terminal Moraines, 360 ; Lakes formed by Permanent Obstruction of Preglacial 
Channels, 362 ; the Formation of Waterfalls, 362 ; Temporary Lakes formed by 
Ice Barriers, 363 ; Supposed Glacial Dam in the Ohio, at Cincinnati, 366 ; Evi- 
dence that the Ice crossed the Ohio, 367 ; Consequences of such an Obstruction, 
368 ; History of its Discovery, 370 ; Theory discussed by the American Associa- 
tion for the Advancement of Science, 371 ; Theory confirmed by the Absence of . 
Terraces in Brush Creek, Ohio, 372 ; by the Terrace at Bellevue, Pa., 375 ; Diffi- 
culty of Other Explanations, 376 ; the Occurrence of Vegetable Matter in the 
Terraces of the Monongahela support the Theory, 377; Teazes Valley, W. Va., ex- 
plained by the Theory, 379 ; Various Other Phenomena explained in a Similar 
Manner, 382 ; Objections considered, 383 ; Claypole on, 386 ; Glacial Dam in the 
Monongahela, 391 ; the Lake Ridges of Ohio and New York, 395 ; Glacial Dam 
aeross the Malawi: and the St. Lawrence, 398 ; Glacial Lake in the Red Reem 
Region of the North: Lake Agassiz, 401. 


CHAPTER XVI. 


THE LOEss : : P 3 : k 407-421 


Extent of the Deposit in China and North America, 407 ; Richthofen’s Theory 
of Deposition by Wind, 408 ; Difficulties of the Theory, 410 ; Characteristics of, 
412 ; Changes of Level Necessary, 413 ; Probable Connection with Glacial Floods, 
415 ; Supplementary Theories, 417. 


CHAPTER XVII. 


FLicut oF PLANTS AND ANIMALS DURING THE GLACIAL 
PERIOD 422-444 


Peculiar Distribution of Plants in the North Temperate Zone, 422 ; Professor 
Asa Gray’s Solution of the Problem, 424 ; more Detailed Statement by Professor 
Gray, 425 ; Comparison of the Pacific with the Atlantic Forests, 426 ; Comparison 


CONTENTS. XV 


PAGE 

of both with those of Japan, North China, and Europe, 427 ; Number of Pre- 
glacial Species now found in the Temperate Zone, 430 ; our Trees originated in the 
High Latitudes, 432 ; the Vicissitudes to which they have been subjected since 
the Approach of the Glacial Period, 433 ; Open Lines of Emigration in America, 
434 ; Peculiar Influences upon the Pacific Coast, 435 ; Extinction of Animals in 
America by the Glacial Period, 436 ; Alpine Butterflies upon the White Moun- 
tains, 438 ; List of Plants common to the Okhotsk-Kamchatkan Region and 
North America, 441. 


CHAPTER XVIII. 


EUROPE DURING THE GLACIAL PERIOD ; ’ 445-459 


Glaciated Area in Great Britain, 445; on the Continent, 447; Investigations 
of Professor Lewis, 448; Summary of Conditions in Great Britain by Dr. 
Harmer, 454; Investigations of Professor Salisbury, 456. 


CHAPTER XIX. 


Tue CAUSE OF THE GLACIAL PERIOD : Lite as / 461-494 


Recent Astronomical Speculations, 461; the Combination of Conditions necessary 
to produce a Glacier, 461; Theories toaccount for the Glacial Period, 463; Decrease 
of the Original Heat of the Planet, 463; Shifting of the Earth’s Axis of Rotation, ~ 
463; Theory of Progressive Desication, 464; Depletion of Carbon Dioxide in the 
Atmosphere, 464; Different Temperatures of Space, 465; Mr. Croll’s Theory: the 
Ellipticity of the Earth’s Orbit and the Precession of the Equinoxes, 466; Possible 
Effect of these upon the Climate, 467; Cause of the Gulf Stream, 469; Causes con- 
trolling the Distribution of the Heat from the Sun, 477; Woeikoff’s Objections to 
Croll’s Theory, 479; Supposed Evidence of Former Glacial Periods, 483; Carbon- 
iferous and Cambrian Glacial! Periods now established, 490. 


CHAPTER XIX (CONTINUED). 


THE CAUSE OF THE GLACIAL PERIOD A : ; s 495-531 


Effect of Changes in the Distribution of Land and Water, 495; Theory of Changes 
of Level, 496; Supplementary Notes by Warren Upham, 520; produced by the 
Accumulation of Snow over Definite Centers, 525; Field for Mathematical Inves- 
tigation, 528; Summary, 529. 


CHAPTER XX. 


Tue DaTeE OF THE GLACIAL PERIOD : : : F 532-615 


Uncertainty of As_ronomical Calculations, 532; Detect in Lyell’s Theory of Uni- 
formitarianism, 533; Post-glacial Erosion below Niagara Falls, 536; below Falls of 
St. Anthony, 552; in Ohio, 560; Freshness of the Glaciated Surfaces, 568; Post-gla- 
cial Erosion in Minnesota, 571; about Lake Michigan, 571; Post-glacial Deposition 
in Kettle-holes, 572; the Question of Two or More Post-tertiary Glacial Epochs, 575; 
Greater Oxidization of Material near the Glacial Boundary, 579; Freshness of In- 
terglacial Forest-beds, 592; Growth of Peat, 594; Extent of Forest-beds, 603; 
Former Extension of Lakes Bonneville and Lahontan, 607; Recentness of these 
Lakes, 610; Length of the Glacial Period, 613; Summary, 614. 


Xvi : CONTENTS. 


CHAPTER XXI. PAGE 


MAN AND THE GLACIAL PERIOD t : : ; : 616-668 


Prominence given by Lyell to the Subject, 616; Artificislity of the Implements, 
617; Professor Haynes ou, 619; Genuineness of, 622; Discoveries of Boucher de 
Perthes in France, 624; of other Investigators in England, 624; of Dr. Abbott in 
New Jersey, 625; Nature of the Gravel at Trenton, 630; Mode of Deposition, 634; 
Series of Events in the Delaware Valley, 639; Discoveriesin Ohio foretold, 640; 
Discoveries by Dr. Metz, in Ohio, 642; Deposit at Madisonville, Ohio, described, 
644; Discovery by Mr. Mills at Newcomerstown, Ohio, 645; Discovery by Mr. 
Huston at Brilliant, Ohio, 648; Cresson’s Discoveries at Medora, Ind., 649; Win- 
chell’s Discoveries in Morrison County, Minn., 653; Miss Babbitt’s Discoveries 
at Little Falls, Minn., 654; Upham’s Discussion of the Deposits in Minne- 
sota, 654. 


CHAPTER XXII. 


MAN AND THE GLACIAL PERIOD (CONTINUED) , : 669-676 


Cresson’s Discoveries at Claymont, Del., 669; Prehistoric Development in the 
Delaware Valley, 674. 


CHAPTER XXIII. 


MAN IN THE MissouRI VALLEY ! ; : ; : 678-686 


Discovery at Lansing, Kan., 678; Nature of the Deposit at Lansing, Kan., 679; 
Nebraska Loess-Man, 683; Nature of Deposit in which found, 683; Discovery at 
St. Joseph, Mo. 685. 


CHAPTER XXIV. 


MAN AND THE LAVA Brps OF THE PaciIFic Coast ; P 687-709 


Whitney’s Discoveries in California, 688; Le Conte on the Quaternary Deposits 
_of California, 689; Whitney’s Evidence in Detail, 692; Stone Mortars from under 
Table Mountain, 694; Criticism of Whitney, 697; the Nampa Image, 701; Conclu- 
sion, 706. 


BIBLIOGRAPHY : : : : : : : 711-741 


EN DEX 3% ‘ : d : ‘ ‘ . 743-763 


LIST OF ILLUSTRATIONS 


Front of Muir Glacier, Alaska, from the southeast corner, looking across the sur- 


face and up one of the tributaries ’ ? : : , . Frontispiece. 
FIG. ; i PAGE 
1. Differential motion of ice : Bree ne , ‘ : . : vee 
2, 3. Differential motion of ice s 2 zg : : . a : ‘ 3 
4. Plasticity ofice . : 5 : 4 f . : 4 : ; Sai 
5. Fissures and seracs 2 : : ; : ‘i ‘ a eet: 
6, 7. Marginal fissures and ian é 8 
8. Veined structure at the junction of Paes bainehen i i z £ é Pio!) 
9. Mode of formation of ice-pillars  . , ; ‘ , F Z ’ : we) 
10. Moraines of the Mer de Glace Cte ee eee Ee gt nD 
11. Glacial scorings = 5 : P eee é , : Se 
12. West end of Samovar Gineier, Masks 2 é 2 : 3 F 5 ‘ yee! 
13. Mount Shasta, California. (Russell.) a 3 A 4 a ty 
14. Mount Tacoma, Washington State, looking wasted,  (Chatios S. Fee.) . oa) 
15. Mount Tacoma, Washington State, looking eastward. (CharlesS.Fee.) . <a 
MME renitheamtornAlsticas (co ee eg 
17. Norris Glacier, Alaska. (Partridge.) . 5 : . £26 
18. Glacier Station, British Columbia. (Canadian Pacific Railroad. ) : ‘ 5 28 
19. Davidson Glacier, Alaska : : : : . 29 
20. Map showing hypothetical former ntennton of Pisctrs: (U. S. Geological 
Survey.) y : 2 : z e , ‘ n 3 : ; «gO 
21. Map of Alaska : : : : ; F . 34 
22. Sketch map of Glacier Bay and Muir insier. (a. F. Reid.) . : . 44 
23. Looking across front of Muir Glacier, Alaska ; é Z 4 : F - 46 
24. Map of Muir Inlet, Alaska . F m : Z F f : : by as 
25. Surface of Muir Glacier. (Partridge.) x : F P : 2 £6 
26. Formation of kettle-hole. Alaska. (Partridge.) . p : Es ‘ . 568 
27. Buried forest on the Muir Glacier : 3 : P : } . 62 
28. Buried forest, Glacier Bay, Alaska 5 D : ; ‘ . : . 63 
29. Muir Glacier from an elevation of 1,800 ae i 5 : : : : . 26a. 
30. Ice-pillars. (Russell.) . : : : F 5 : : ; , 1 lana 
31. Map of Greenland é ‘6 - 3 ‘ ¢ : Seki 
32. Map of Frederickshaab Uikoler. Cesuatta. aie} : < ‘ ; 3 . 81 
33. Ikamiut Fjord, Greenland, showing hanging glaciers . F ; : ; 83 
34. Sea margin of Cornell Glacier, Greenland . : < - 108 
35. Glacier in North Greenland, showing upper strata of ee rolling over like brea ie 103 
36. Morteratsch Glacier, Switzerland F hina a P F p i . 105 
37. Svartisen Glacier, Norway. (Warner.) 5 A 5 ‘ a A ‘ . 106 
38. Iceberg . ; 5 p : : : . J s : : ; : . 116 
39. Floating berg . : ; ‘ 5 : ‘ 4 . 119 
40. Scratched stone from till of Boston, Mass. Se UE ANE ls a ee ee ree 


Xvii 


XVili LIST OF ILLUSTRATIONS. 


. Glacial striz, Amherst, Ohio. (Chamberlin.) 

. Cut in till, Hamilton, Ohio 

. Cut in till, Darrtown, Ohio . 

. Glacial map of southern New Raeland” 

. Glacial map of New Jersey .. 

. Glacial map of Pennsylvania and catthein New York 

. Glaciated pebble, Pennsylvania 

. The same, side view ‘ : : 

. Attenuated border, eastern Bevigapkyadint (Williams.). 

. Lake Lesley, Pennsylvania , 

. Advance of Wisconsin Ice over the Kanbad borders near the apex of N ew ark 
. Lake Allegheny 

. Map of the upper Witesticny Valley, Pa. 

. Sand pit at Warren, Pa. 

. Bar at Warren, Pa. 

. Glacial map of Ohio ; 

. Glacial map of southern Indiana . 

. Glacial map of southern Illinois 

. Typical section of till in Seattle, Washington State 

. Section of modified drift at Point Wilson, Washington State 

. Glacial groovings, Victoria, British Columbia 

. Glacial map of North America : ‘ 

. Depth of ice and erosion in eastern Peni eaae (Lesley.) 

. Map of kettle-holes near Wood’s Holl, Mass. 

. Map of morainal deposits, western New York. (U. s. Gleoletianl cee! ) 
. View of kettle-moraine, Eagle, Wis. (Chamberlin.) 

z Map of the Missouri coteau. (Todd.) . 4 

. Glacial map of central British America. (Dawson.) 

. The Missouri coteau. (Dawson.) . : _ : : : : : . 
. Canon of the Colorado. (Newberry.) . P : : : : Z - 
. Embossed floor of an ancient glacier, Colorado. (Hayden.) 

. Glacial bowlder, Gilsum, N. H. (Hitcheock.) 

. Mohegan Rock, Montville, Conn. . 

. Glaciated pebble, Indiana 

. Reverse side cf the same 

. Ideal section showing distribution of till a » : 

. Ideal section showing sub-aérial disintegration. (Chamberlin.) 

. Glacial grooves, South Bass Island, Lake Erie : Z : : 

. Tortucus glacial grooves, Kelley’s Island, Lake Erie. (Chamberlin.) 

. Section of glacial furrows, Kelley’s Island, Lake Erie 

. Full view of the same. (Younglove.) . 

. Glacial furrows, South Bass Island, Lake Erie 

. Glacial furrows, Gibraltar Island, Lake Erie 

. Cross striae, Middle Bass Island, Lake Erie 

. Iowan bowlders. (Calvin.) 

. Map of drumlins near Boston. (Davis. ) 4 : 

. View of Corey’s Hill, Brookline, Mass. A typical iaidialin.  @ane 

. Outline of drumlins in Boston Harbor. (Davis.) 

. Map of drumlins in northeastern Massachusetts. (Davis.) 

. Outline of drumlins, central New York. (Davis.) 

. Drumlins in Wisconsin. (Chamberlin.) 

. Drumlins in Goffstown, N. H. (Hitcheock.) 

. Drumlins in Ireland. (Kinnehan and Close.) 

. Section of the valley of the Cuyahoga River. (Claiwels: ) 4 : 
. Cross-section showing old and new channels of the Mississippi River, (Iowa 


GeologicalSurvey.) 3 cee A ; A : < ; = 


LIST OF ILLUSTRATIONS. xX1x 


FIG. PAGE 
96. Drainage map of southeastern Iowa. (Leverett.) ’ d E ; : . 318 
97. Cross-section of the Osage trough at Tuscumbia, Mo. . : F : j . 318 
98. Map showing glaciated and unglaciated portions of Missouri ; : : . B22 
99. Glacial terrace, Granville, Ohio. ‘ Sects . 323 
100. Map of South Dakota showing the channel of the Seoul —— : : . 335 
101. Maps of kames in eastern Masschusetts F é : ’ : ; . . 338 

_ 102. Section of kame, Dover, N. H. (Upham.) i : F : ; ‘ . 340 
103. Sections of kame, Bennington Station, N. H. . ; : : ; : . 341 
104. Map of the kames of Maine. (Stone.). ; é ; é : P ‘ . 344 
105. Section of buried kame, Hanover, N. H. (Upham.) ‘ : , ‘ . 845 
106. Section of kame, Hanover, N. H. (Upham.) . : 5 : F . 346 
107. Buried kame, Stroudsburg, Pa. (Lewis and Wright. nf ? : ; . . 348 
108. Canadian bowlder, Boone county, Ky. é : : : d . 368 
109. Map showing the effect of the glacial dam at Cieainnintt, (Claypole.) : . 369 
110. Map of Paint Creek and Beech Flats, Ohio : : . : : r . 373 
111. Section of a deposit, Teazes Valley, W. Va. : : fe , s : . 380 
112. Split Rock, Boone county, Kye . F ; : : F é ; F ~ 385 
112a. Glacial map of Lake Cuyahoga. (Claypole.) . 3 : ; F ; . 388 
113. Section of the lake ridges near Sandusky, Ohio . , f ‘ : - . 390 
114. Map showing glacial lakelets in northern Ohio. (Claypole.) . P , . 396 
115. Lake Whittlesey. (Leverett.) . : ; = 4 3 : : : . 399 
116. Lake Warren. (Leverett.) . ; : : . i f y . 399 
117. Nipissing Great Lakes and Gismplam Seu ‘ 5 = : 4 : . 399 
118. Map of glacial lake, Erie-Ontario. (Claypole.) . : 5 h : 4 . 400 
119. Stratified loess, Nebraska. (Chamberlin.) , , 3 ; : : -, 410 
120. Gulley in the loess, Helena, Ark. (Crider.) aS ; ; : ae ~ 421 
121. Polarprojections : % : - 428 
122. Map showing glaciated areas +" Worth Abne¥iind —" Riuhaeage 4 $ Suite 445 
123. Glacial map of Europe ; : Z ; : : é é ; . 456 
124. Contorted drift of the Cromer ridee : ; : : d : x : . 458 
124a. Present and past glaciation of the Alps. (Leverett.) ; : 2 5 . 460 
125. Diagram showing eccentricity of the earth’s orbit . ; ‘ fats . 466 
126. Map showing Atlantic Ocean currents d : \ : . . : . 470 
127. Map of July isobars and prevailing winds . : : : : é 3 . 471 
128. Map of January isobars and prevailing winds . : : F . : . 474 
129. Glaciated pebble. (Coleman.) . J : : : 3 é ‘ : 493 
130. Glaciated Pebble. (Coleman.) LET Ss Da iNh a RO Hea egoraiel! ..ae8 
131. Glaciated Pleistocene surface. (Coleman.) . : 3 : : : . 493 
132. Bird’s eye view of Niagara River. (Pohlman.) ’ ; ; : : . 535 
133. Section of strata along the Niagara gorge . : ; é ; : ; . 537 
134. Map of the Niagara River below the falls Bay ? : ; ; , O08 
135. Map showing recession of Horseshoe Falls since 1842. : : : S . 540 
136. Exposure of Niagara shale in Niagara gorge. (Dutton.) : : . 544 
137. Diagram of mouth of Niagara gorge at Lewiston . : : ‘ F . 544 
138. Photograph looking northwest towards St. Davids . { . 546 
139. Section showing enlargement of Niagara gorge on east side at its ‘ahi: . 546 
140. Hypothetic hydrography of the Great Lakes after the melting of the glacier from 

the St. Lawrence Valley . : 547 
141. Sections showing the actual rate of cnbiiha ing the sides of the Meealirs 

gorge. : j ; . 551 
142. Map of Sseaiedisct Brow: aes Fort Snelling to ken biGlis ‘ ’ “ . 555 
143. Ideal view of an unglaciated country. (Chamberlin.)  . : : . 662 
144. Ideal view of glaciated country. (Chamberlin.) ; j : ; . 563 
145. Meanderings of Plum Creek through 5,000 feet of its idugh - . 564 
146. Cross section of the new course of Plum Creek . ; , 4 ; ‘ . 564 


147. Section of kettle-hole, Andover, Mass. . 7 x A i F . 572 


xX 


FIG. 


148. 
149. 
150. 
151. 
152. 
153. 
154, 
155. 
156. 
A5y. 
158. 
159. 
160. 
161. 
162. 
163. 
164. 


165. 
166. 
167. 
168. 
169. 
170. 
171. 
172. 
173. 
174. 
175. 
176. 
177. 
178. 
179. 
180. 
181. 
182. 
183. 
184. 
185. 
186. 


187. 
188. 


189. 


190. 
191. 
192. 
193. 
194. 
195. 
196. 


LIST OF ILLUSTRATIONS. 


PAGE 
Perpendicular section of till containing wood, Oxford, Ohio . F ) ag oi 
Part of Atlanta, Mo., topographic sheet . : bane 4 aa 
Part of Oelwein, Ia., topographic sheet . . ; ; ; : : . 589 
Section of till overlying peat, Germantown, Ohio . : ‘ ; : . 593 
Section of kettle-hole, Freehold, Pa. . 3 5 ; . 598 
Section in till containing wood, Darrtown, Bales cisaiten Ohio : 7 . 599 
Forest lately disturbed by an advancing Alaskan glacier. (Gilbert.) . . 606 
Map of the ancient lakes Bonneville and Lahontan. (Le Conte.) .- . . 608 
Bowlder bed at Pocatello, Idaho : : : : : : - F . 615 
Collection of palzolithic implements : , : js ] : ; . 616 
Reverse side of the same . } } 4 : : : 3 ‘ . 617 
Argillite implemenc, Trenton, N. J.) « @0;/985.)/ (Putnam). ? i . 626 
Side view of the same. (Putnam.) . ; : : , : : K . 627 
Argillite implement, Trenton, N. J. (11,286.) (Putnam.) . . Z ~ 628 
Black chert implement, Trenton, N. J. (10,986.) (Putnam.) 2 : .. 629 
Section of Trenton gravel, N. J. (Abbott.) : , d 5 . 631 
Gravel deposit at Trenton, N. J., where human femur was foustil: (Records 
of the Past.) . 3 s 3 ‘ . 682 
Ideal section on the Dekawaie River Valley, Preedon N. i: (Abbott.) . . 633 
Black chert implement, Madisonville, Ohio. (40,970.) (Putnam.) . ; . 642 
Map showing glacial boundary, channels, and terraces near Cincinnati . . 643 
Paleoliths from Newcomerstown and Amiens . : , A; : : . 646 
Edge view of the same 2 : : 3 ; : : . 647 
Face view of implement from Brilliant, Ohio : : é i : : . 648 
Face view of same : F z ; ‘ 4 ae . : : . 648 
Diagonal view of same ? : ; : ‘ _ ; . 648 
Section of the trough of the Ohio at Brilliant é ‘ 3 : é ; . 649 
Gray flint implement, Medora, Ind. (46,145.) (Putnam.) : ; ‘ . 650. 
Side view of the same. (Putnam.) . : Mee ' : ; r . 651 
Section of gravel at Medora, Ind. : , ‘ : Werke? : a SS 
Chert implements, Morrison county, Minn. (Winchell.) ; : : . 653 
Quartz implement, Little Falls, Minn. (31,323.) (Putnam.) . P : . 657 
Quartz implement, Littie Falls, Minn. (31,316.) (Putnam.) . : : . 658 
Ideal section, Little Falls, Minn. (Upham.) . : : 2 s ; . 660. 
Map of moraines in Minnesota. (Upham.) ; : p ¢ . 662 
Accumulating delta plain in front of Malaspina @teiten: ‘(ase , . 667 
Baltimore and Ohio Railroad cut, Claymont, Del. (Cresson.) ¢ ; . 670 
Nearer view of the same. (Cresson.) : : . 672 
Argillite implements from the preceding cut. (45, 726. ) (Partunatal: ) : . 674 
View showing Mr. Concannon’s house and relation of the bluff to present 
flood plain of the Missouri. (Records of the Past.) . g F : . 677 
Geology of the Concannon Farm £ ‘ . 679 
Entrance to tunnel in which Lansing dicoleenie was diate. (Redon of ihe 
Past.) 2 F J ote - eee 
Front view of skull ra fecaite ones of ion sleclitent, (Records of the 
~Past.)) . 5 : é ‘ = H . 681 
Side view of same. (Records of ie Past; ) F ; 5 ; ; . 681 
Section of Long’s Hill, Neb. (Records of the Past. ) , ! - : . 684 
Implement from Dug Hill. (Owen.) : ; : : A A . 686 
Lava streams cut through by rivers in Calientes (Le Conte.) : . 689 
Section across Table Mountain, Cal. (Le Conte.) . E 3 " * . 689: 
MecTarnahan mortar from under Table Mountain . n - - . 697 


Nampa figurine and map of the Snake River Valley ‘ - ‘ . 703 


LIST OF ILLUSTRATIONS. XXl 
PAGE 

Map showing the glacial geology of the United States and southern 
Canada ri t P between 134 and 135 
Map showing the areinelal pee of the Gat aed ‘ between 300 and 301 
Map of the glacial Lake Agassiz . j ‘ : : : ; : .. facing 404 


LIST OF PLATES. 


PAGE 
I. Sperry Glacier, Montana. (Sperry.) . : a i, eines 
II. Geikie Glacier and Hanging Glacier, British Canudatiie: (Canadian 
Topographical Survey.) . : J ; . facing 18 
Ill. View of Illecillewaet and Naticen ‘Glaciers, British Columbia. 
(Wheeler.) i : : . . facing 25 
IV. Forest on top of front of KGieantan Glsuier, idstia. (Russell.) . . facing 33 
V. Muir Glacier in 1909 : M . between 74 and 75 
VI. North outcrop of Mammoth Bed ovetintd hy seaciaae till, Morea, Pa. 
(Williams. ) 5 ‘ . facing 154 
VII. Topography of deep — tw ie abuth of siete oi Iowan drift, 
northwest ot lowa City, Iowa. (Todd.) . : d ‘ . facing 227 


VIII. Stream of water along the margin of Malaspina Glacier. (Russell) facing 320 
IX Longitudinal kames near Hingham, Mass. (Bouvé.) . 2 . facing 340 


4}, ere 
i 
a 


A ade 


re 


THE ICE AGE IN NORTH AMERICA, 


CHAPTER I. 
WHAT IS A GLACIER? 


To the ordinary man of science, water is a mineral and 
ice a rock; but to the glacialist both are fluids. The appar- 
ent solidity of ice is an illusicn due to the dullness of our 
senses. The reason why its viscous or semi-fluid character 
remained unsuspected until a comparatively recent period is 
due to the fact that the ordinary movement of accessible 
glaciers was so slow that we could not by observation readily 
note their rate of progress. 

The difference between water and other substances is 
most noticeable in the phenomena connected with solidifi- 
cation and fusing. Lead melts at 612° Fahr. above zero; 
sulphur, at 226°; water, at 32°; while mercury becomes 
liquid at 39° below zero, and some other substances at even 
lower temperatures. Thus, with reference to its fusing- 
point, water appears toward the middle of the scale. If, 
like the fabled salamander, man were able to endure intense 
degrees of heat, he might, very likely, sustain relations to 
iron similar to those he now sustains to water. He might 
then bathe with pleasure in a molten flood, and venture on 
the thin crust of a glowing mass of metal. 

The suddenness with which water passes from the solid 
to the liquid state, and the amount of heat absorbed in the 
process of fusion, involve many important consequences. 
Down to the freezing-point water may be made to part with 
its heat by gradual stages, but in the act of freezing it sud- 


2 THE ICE AGE IN NORTH AMERICA. 


denly gives out an enormous amount of heat; on the con- 
trary, when ice melts, a corresponding amount of heat is 
absorbed in accomplishing the result. To melt a cubic foot 
of ice requires as much heat as to raise a cubic foot of water 
80° C. or 144° Fahr. 

For our knowledge of the nature of the movements tak- 
ing place in glaciers, we are largely indebted to the investi- 
gations of Louis Agassiz and Professor Forbes between the 
years 1840 and 1842, and later to more detailed investigations 
of Professor Tyndall and other physicists. The mode of 
measurement with all these investigators was essentially the 
same. Stakes were driven across a glacier in a line at right 
angles to the direction of the movement; and, by means of a 
theodolite, accurate notations were taken, from hour to hour 
and day to day, of any changes in the relative position of 
the as where the stakes were driven. The uniform re- 
sult of these observations was that the 
line of stakes began immediately to curve 


pee oe 2 slowly down near the middle, showing 
oq e-o"°e| that the motion on the surface was greater 
lees etc: near the middle than on the sides. This 

Bong. ..2° 9] curve continued to increase as long as 


“50.22 .0°°7 
cng el F the stakes remained standing. 
Professor Tyndall’s observations show 
Fro, 1,—The letters 4,2 also that the most rapid line of motion 
c, d. e, f, g, represent on the surface of a glacier is not exactly 


stakes driv en across the 


surface of a glacier, at jn the middle; but that, wherever there 
right angles to its line 


EB —— ;,@’, d', ¢, js a bend in the glacial current, the more 
Coins q’. represent : 4 2 

these positions at a rapid movement is uniformly on the con- 

quent stage. ; 

vex side of the channel, so that the curve 

of the line of most rapid motion is more tortuous than that 

of the main channel. This conforms to the facts concerning 

the movement of water in a crooked river-bed, and illustrates 

again the analogy between the movement of ice and that of 

water. 
The most rapid: motion observed by Tyndall in the sum- 
mer time, in the center of one of the largest of the Alpine 


WHAT IS A GLACIER? 


glaciers, was thirty-seven inches per day. 


3 


Near the sides of 


the glacier. however, the movement was reduced to two or 


three inches. The rate of motion during 
the winter was only about one half that 
during the summer. 

A further resemblance of the motion of 
a glacier to that of a river appears in the 
fact that the ice near the top moves faster 
than that near the bottom. At a point in 
the Mer de Glace where the side of the gla- 
cier is exposed, presenting a wall of ice 
about one hundred and fifty feet in height, 
Professor Tyndall drove three stakes; one 
at the summit of the ice, another thirty-five 
feet from the bottom, and another four feet 
from the bottom. Upon examination of 
them, at the end of twenty-four hours, it 
appeared that, while the top stake had 
moved forward six inches, the middle one 
had moved but four and a half inches, and 
the bottom stake but two and two thirds of 
an inch. 


Fie. 2.—The continu- 


ous lines define the 
valley occupied by 
the glacier. The 
dotted line with the 
arrow -heads indi- 
cates the line of 
most rapid motion 
in the ice, showing 
its more sinuous 
course. 


In all these experiments the influence of friction is clearly 


~ visible. 


Fie. 3.—a, b, c, are stakes driven in the vertical 
wall of the side of a glacier; a’, b’, c’. are 
the points occupied at a subsequent date. 

ence. 


The ice of the glacier is retarded by the friction of 
the sides and bottom of 
the channel through which 
it moves, so that the most 
rapid motion is upon the 
surface, near the middle, 
the part farthest removed 
from this retarding influ- 


A little attention to this last principle will prepare the 
mind for crediting the observations which more recently 
have been reported from the large glaciers in Greenland and 
Alaska, showing a motion fifteen or twenty times that of 
the Alpine glaciers. As the cross-section of a glacier is in- 


4 THE ICE AGE IN NORTH AMERICA, 


creased, the relative influence of friction in retarding the 
motion is rapidly diminished. The friction on the sides of 
a glacier two miles wide is no greater than that upon one a 
quarter of a mile in width, though the cross-section is eight 
times as large. A cross-section of the Mer de Glace at Les 
Moulins is estimated to be one hundred and ninety thousand 
square yards ; whereas a cross-section of the Muir Glacier, in 
Alaska, a mile above its mouth, is upward of one million 
square yards. 

Though observation shows that ice actually moves as if it 
were a fluid, the scientitic imagination is tasked to the utmost 
to conceive how such motion can be consistent with other 
manifest qualities of the material; for in many conditions ice 
seems as brittle as glass and as inelastic as granite. The 
mystery is probably solved, so far as such questions are ever 
solved, by attention to the facts already referred to concern- 
ing the behavior of ice at its melting-point. When ice passes 
into water, an immense amount of heat is absorbed in the 
process, which yet does not produce any effect upon the 
thermometer. Ifa hole be bored in the surface of a melting 
glacier, and a thermometer inserted, it will stand at 32° Fahr. 
If the same thermometer be inserted in the subglacial stream 
issuing from the ice front, it will stand at the same point. 
Yet the absolute difference between the heat contained in 
the particles of ice, and that contained in the particles of 
water, is 144° Fahr.—so much heat being occupied in keep- 
ing the substance in a liquid form. Ice is also transparent 
to the rays of heat as it is to the rays of light. Scoresby 
amused himself, in the arctic latitudes, by making lenses of 
ice with which to concentrate the sun’s rays and set com. 
bustible substances on fire. 

The fusing-point of ice is also modified by pressure. 
Under pressure the freezing-point of water may be lowered 
two or three degrees; but upon the removal of the pressure, 
the water will instantly become solid. This has been demon- 
strated in various ways. M. Boussingault, for example, filled 
a hollow steel cylinder with water, having a bullet loose with- 


WHAT IS A GLACIER? | 5 


in it, and plugged the aperture up. He then subjected the 
eylinder to intense cold till the whole was two or three de- 
grees below the freezing-point of water. But that the water 
remained liquid was evident from the fact that, upon shaking 
the cylinder, the bullet inside rattled about as at higher tem- 
peratures; while, upon removing the plug so as to relieve 
the pressure, the whole was iustantly converted into solid 
ice. Various similar experiments have been made in which, 
upon removal of the plug, the water ejected from the aperture 
by the expansive power of the cooling water within the 
cylinder immediately freezes, and forms a projecting column 
of ice several inches in length. It was at first thought that 
this projecting column illustrated the plasticity of ice; but 
it is now pretty certain that it illustrates, rather, the curious 
effect of pressure upon the freezing-point of water. 

The capacity of water at the freezing-point to transform 
itself, under varying degrees of pressure, from the solid to 
the liquid state, and vvce versa, is illustrated by another ex- 
periment, ascribed by Professor Tyndall to Mr. Bottomley. 
A copper wire was looped over a bar of ice about four inches 
square, and a weight of twelve or thirteen pounds was sus- 
pended from it. The pressure under the wire caused the ice _ 
in immediate contact with it to melt; but, as the resulting 
water escaped around the wire, and was relieved from press- 
ure, it immediately froze, and cemented together again the 
walls of ice above the wire. In half an hour the wire had 
cut completely through the bar of ice, and yet the whole 
breach above it was repaired, and the bar was intact. 

This capacity of fragments of ice, when near the melting- 
point, to freeze together when their faces are joined, can be 
readily observed ina variety of experiments. When two 
pieces of ice in a basin of warm water are brought together 
they will immediately adhere. If a cake of ice whose tem- 
perature is near the melting-point be placed in a mold and 
subjected to pressure, the first result is to break it into pieces ; 
but, on continuing the pressure, the - particles reunite and 
freeze together into a shape corresponding to that of the 


6 THE ICE AGE IN. NORTH AMERICA. 


mold. This capacity of ice, when near the melting-point, 
to undergo disintegration, and then to become suddenly re- 


A C 


Fig. 4.—A, B, C, molds; a, ¢c, e, original forms of the ice; 6, d, f, the forms into which 
they were molded. 

congealed, is probably that by which it simulates in its mo- 

tion the properties of ordinary fluids, while at the same time 

retaining other properties connecting it with the most brittle 

of substances. | 

It is thought, by Mr. Croll and others, that when heat 
passes through a stratum of ice, as it is known to do, it involves 
a process of transference from one particle of ice to another, 
in which there are successive melting and freezing of the 

particles in the progress of the heat, and that finally the mole- 
cule of ice upon the opposite side, in becoming recongealea, 
delivers up the unit of heat which had entered the stratum 
from the other side. But, whatever be the explanation of 
the process, the facts remain that ice behaves in many re- 
spects like a fluid, and, on application of pressure. slowly ad- 
Justs itself to its bed or mold in obedience to the force ap- 
plied, and, if time enough is given, moves wherever a fluid 
would find its way. Ice is plastic under pressure and brittle 
under tension. 

Snow is one form of ice, and, as every school-boy who 
makes a snow-ball knows, can by a moderate degree of press- _ 
ure be made into compact ice. The reason why snow is 
white, and ice is blue, is that snow is pulverized, while in 
ice the particles are brought into closer contact, and the 
inclosed air is expelled, so that the real color of the substance 


WHAT IS A GLACIER? y. 


is brought out. The powder of almost any substance differs 
in color from the compact mass. Glacial ice is compressed 
snow, and originatés wherever the snow-fall is largely in ex- 
cess of the melting power of the sun and warm currents of air. 
Any one can observe how much more compact old snow is 
than new, and how, under pressure, the lower strata in a 
snow-bank become in a single season. almost like ice. Hence 
it is easy to see what must be the result where the annual 
snow-fall is never wholly melted away. In such regions the 
ice would accumulate without limit, were it not for its semi- 
fluid character, which permits it to flow off, in lines of least 
resistance, to lower levels and toward warmer climes. 

In structure glacial ice is characterized by both veins and 
Jissures—two phenomena, which are produced by opposite 
canses—the first by pressure, and the second by tension. 

Glacial ice ordinarily presents a veened structure. Instead 
of being homogeneous, it consists of alternate bands of light- 
colored and blue ice. ‘These bands do not, however, lie in a 
horizontal position, but are often vertical. Sometimes they 
run parallel with the movement of the glacier, and sometimes 
at right angles to the motion ; while, at other times, they are 
arranged at an angle of forty-five degrees, pointing down the 
line of motion. From close examination it appears that the 
veins are always at right angles to the line of greatest pressure. 

For example, where two branches of a glacier join, and 
press together from the sides, longitudinal veins are produced 
below the point of junction. And again, where ice has de- 
scended a declivity, and is advancing upon a less inclined 
plane, the increased pressure necessary to push the mass along 
produces bands at right angles to the line of motion; thus 
demonstrating the connection of veins with pressure. The 
theory is, that the blue veins in the ice are those from which 
pressure has expelled the particles of air, thus making it 
more compact, and giving it its blue color. As already re- 
marked, snow is white because of the abundant particles of 
air inclosed within it. Under pressure it can be transformed 
ito blue ice, corresponding to the blue veins alluded to. 


THE ICE AGE IN NCRTH AMERICA. 


(@-6) 


An active glacier is also characterized by jisswres. When- 
ever the ice-stream reaches a point where its slope is increased 
even by a very small amount (a change in inclination of two 
degrees being sufficient), the ice instead of moving in a con- 
tinuous stream, forms crevasses across the current, which 
gradually enlarge at the top, until they present a series of 
long chasms, very difficult for the explorer to traverse. 
Where there is considerable irregularity in the bottom, and 
the increased slope extends for some distance, these crevasses 
become very complicated, and the surface presents an ex- 
panse of towers and domes and pinnacles of ice, often of fan- . 

tastic appearance ; 
Vane but at the bottom 
these masses are 


If | 
Nf Manns still joinedaeaeee 
| l ! | i Cc J >) 
aA M9 coming down to a 


gentler slope they 
close up again at 


Fic. 5.—c, ¢, show fissures and seracs where theglaciermoves the surface for 
down the steeper portion of its incline; s,s, show the a 
pees structure produced by pressure on the gentler their onward 
slopes. 


| 
i\ 


march. 

_ In addition to the crevasses or fissures, produced by the 
tension where the ice-stream passes over a steeper incline, a 
set of marginal fissures extend from the sides of the glacier 
toward the center, but pointing upward at an angle of about 
forty-five degrees. These, 
too, appear to be the result ( 
of tension. The motion of au 
the ice in the center, being ive 
more rapid than that to- 
ward the sides, producesa | / ! 
line of tension, or strain, ex- 
tending from the center di- 4 
agonally downwar d toward Fies. 6, 7 eee the totais ae 
the sides at an angle of al fissures and veins. 
forty-tive degrees. The pressure upon these masses of ice, 
whose central point is being wheeled downward by the differ 


i Vere ae oes To 2 


WHAT IS A GLACIER? 9 


ential motion, produces also a veined structure in the masses 
themselves, at right angles to these marginal fissures. 

The surface of a glacier presents many interesting phe- 
nomena. When the ice-stream is of sufficient size, the sur- 
face is covered with a network of 
small streams of water, flowing through 
blue channels of ice sometimes many 
yards in depth and width. but these 
are destined eventually to encounter 
some crevasse, where a circular shaft, 
or moulin, as it is called, is formed, 
opening a way to a subglacial chan- 
nel, into which the streams plunge fe. 8.—tustrates the forma- 
with a loud roar, and the accumulated preeeeve aly the guhction ct 
waters may often be heard rushing Bis sta 
onward hundreds of feet below the surface. During the 
melting of a glacier, also, in the summer season, the surface 
of the ice is frequently dotted with bowl-shaped depressions, 
from one or two inches to many feet in depth, and filled 
with beautiful clear water. The cause of this can not well 
be conjectured. In Greenland, Nordenskidld attributed the 
initial melting to accumulations of meteoric dust which he 
named kryokonite. 

Glaciers in mountainous regions are also characterized by 
lateral and medial moraines. Where the ice stream passes 
by a mountain-peak, the falling rocks and the avalanches 
started by streams of water, form along the edge of the gla- 
cier a continuous line of débris, which is carried forward by 
the moving ice, and constitutes what is called a lateral mo- 
raine. If there be a current of ice on each side of the mount- 
ain-peak, two of the lateral moraines will become joined be- 
low the mountain, and will form what is called a medial 
moraine, which will be carried along the back of the ice as 
far as the motion continues. As the ice wastes away toward 
the front, several medial moraines sometimes coalesce. This, 
as will be seen, is finely shown in some glaciers of Alaska. 

A medial moraine, when of sufficient thickness, protects 


10 THE ICH AGE IN NORTH AMERICA. 


the ice underneath it from melting; so that the moraine 
will often appear to be much larger than it really is: what 
seems to be a ridge of earthy material 
being in reality a long ridge of ice, thinly 
covered with earthy débrvs, sliding down 
the slanting sides as the ice slowly wastes 
away. Large blocks of stone in the same 
, manner protect the ice from melting un- 
Fie. 9._Mode of formation derneath, and are found standing on pe- 
ae destals of ice, where the general surface 

has been lowered sometimes several feet. An interesting 
feature of these blocks is that when the pedestal fails, the 
block uniformly falls to- 
ward the sun, since that 
is the side on which the 
melting has proceeded 
most rapidly. 3 
All the material 
brought down upon the 
surface of the glacier in 
the medial moraines is 
deposited ‘at the front, 
forming a terminal mo- 
raine, which will vary in 
size according to the 
abundance of material 
transported by the ice, 
and in proportion to the 
length of time during 
which the front rests at 
a particular point. But, 


TT 


a 


e . e ON SS - 4 \ = 
ordinarily, for a consid- 1; Ari alg WS 
° F My) ll WENA NS SS 
erable distance this mo- N at — 
raine material near the He NE Cal 
MEG 


front will rest upon ex- 
Fie. 10.—Mer de Glace. The parallel lines in the 


tensive Masses of 1c€ middle are medial moraines, The main ice- 


: stream on the right pushes the others to the wall, 
which only slowly melt and divides the terminal moraine above g. 


WHAT IS A GLACIER? 11 


away. It is largely owing to this that a true terminal 
moraine is made up of knolls and bowl-shaped depressions 
ealied ettle-holes, and ot short tortuous ridges of bowlders 
and gravel. : 

Another result connected with the decay of a glacier is 
the production of kames—this being the Scotch word for 
sharp, narrow ridges of gravel, corresponding to what are 
called osars in Sweden and eskers in Ireland. The trend of 
these ridges is the same as that of the motion of the glacier, 
and is at right angles to the terminal moraine. Their for- 
mation can be witnessed on a large scale near the front of 
the Muir Glacier in Alaska. In certain localities a great 
amount of sand, gravel, and bowlders becomes spread out 
over the surface of the ice at a considerable elevation. 
Through some changes in the subglacial drainage a stream 
wears a long tunnel in the ice underneath this deposit, 
which at length proceeds so far that the roof caves in, and 
the earthy débris is gradually precipitated to the bottom 
of the tunnel, thus forming one class of kames. In other 
places, evidently, water-worn channels in the ice have been 
silted up by the stream, and then the line of drainage 
changed, so that, when the supporting walls of ice melted 
away, another class of kames, with what is called “ anticli- 
nal” stratification, is produced. 

It should be mentioned also that, after the analogy of a 
river, a glacier shoves sand and gravel and bowlders under- 
neath it along its bed; from which it can easily be seen that 
a glacier is a powerful eroding agency, rasping down the 
surface over which it moves, and by the firm grasp in which 
it holds the sand, gravel, and bowlders underneath it, pro- 
ducing grooves and scratches and polished surfaces on the 
rocks below, whiie these stones themselves will in turn be 
scratched and polished in a peculiar manner. Wherever the 
glaciers have receded, so that their bed can be examined, 
these phenomena, which we reason from the nature of the 
case must lave been produced, are found actually to occur, 
and a terminal moraine is sure to contain many pebbles and 


ii 


i 
=) im 


12 THE ICH AGE IN NORTH AMERICA. 


bowlders bearing marks of the peculiar attrition to which 
they have been subjected in their motion underneath the 
ice. The rocks brought along upon the surface of the gla- 
cier of course are not thus striated, and ordinarily the mate- 


Fie. 11.—Glacial scorings (after Agassiz). 


rial of the kames has been so much rolled by water that if 
the pebbles ever were scratched, the marks have been erased. 

With this brief account of the physical characteristics of 
ice, and of the effects produced by its movement in a gla- 
cler, we are prepared to enter more understandingly upon a 
survey of the actual facts relating to the past and present 
extent of the ice-fields over the northern part of North 
America. Reserving the discussion of theories concerning 
the cause and date of the glacial period to the latter part of 
the treatise, we will first consider the facts concerning the 
glaciers still existing in America, and then briefly, by way of 
comparison, those concerning glaciers in other portions of 
the world; after which we will present in considerable 
detail the more recent discoveries concerning the extension 
and work of the great American ice-sheet during the so- 
called Glacial period. 


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CHAPTER II. 
GLACIERS ON THE PACIFIC COAST. 


NOTWITHSTANDING the great height of the Rocky Moun- 
tains, they are, in the southern part, devoid of living glaciers. 
This lack is doubtless caused by the dryness of the atmos- 
phere, the winds from the Pacific having already, before 
reaching the interior, yielded their moisture to the solicita- 
tions of the lofty peaks of the Sierra Nevada and the Cascade 

Range. Still, a few small glaciers are found among the sum- 
mits of the Wind River Mountains of Wyoming, and near the 
sources of Flathead River in Montana. Farther north, how- 
ever, near the Canadian boundary, glaciers begin to appear 
in increasing number and size. The broad picturesque sum- 
mits of the Rocky Mountains forming the continental divide 
between the head-waters of the Flathead River in Montana 
and those of the Belly,a branch of the Saskatchewan, in 
Canada, support innumerable glaciers of small size and many 
that compare Well with those of the Alps. More than forty 
are found between Lake McDonald and the Canadian bound- 
ary. Of these the Sperry and Chaney glaciers are most 
conspicuous. Avalanche Lake, surrounded by glacier-cov- 
ered peaks, is one of the most picturesque localities on the 
continent. | 

In the Canadian Rockies and in the Selkirk Mountains, 

- north of the line, in Alberta and British Columbia, glaciers 
increase in numbers and size as higher latitudes are reached. 
Of these the Victoria, the Wenkchemna, the Yoho, the [llecille- 
waet and the Asulkan are so near stations on the Canadian 


14 THE ICE AGE IN NORTH AMERICA. 


Pacific Railroad that they can be easily visited by tourists. 
The snow-fields of all these are from 9,000 to 10,000 feet above 
sea-level, but none of the glaciers descend much below 6,000 
feet, except the Illecillewaet which reaches the level of 4,800 
feet. cae 


Fie. 12.—West end of Samovar Glacier. Alaska. 


A wide arid space, of which few who have not traversed 
the region can have any conception, separates the Rocky 
Mountains from the Sierra Nevada nearer the Pacific coast. 
This latter range of mountains is, in some respects, favorably 
situated for the production of glaciers, since the peaks are 
lofty, rising in many places upward of 14,000 feet, and there 
is abundance of snowfall. Ordinarily, however, there is not 
breadth enough to the summit of the range to furnish ade- 
quate snow-fields for the production of first-class glaciers. 

The most southern collection of glaciers in the Sierra 
Nevada is found near the thirty-seventh parallel, a little 
east of the Yosemite Valley, in Tuolumne and Mono coun- 
ties, California. Here is a remarkable cluster of mount- 


GLACIERS ON THE PACIFIC COAST. 15 


ain-peaks rising upward of 14,000 feet above the sea, and 
with breadth enough to support numerous snow-fields and 
glaciers. No less than sixteen glaciers of small’ size have 
been noted among these summits, of which those on Mount 
Dana, Mount Lyell, and in Parker Creek are the principal. 
None of them, however, are of great size, being in no case 
over a mile in length, and none of them descending much 
below the 11,000-foot line.* 

The continuation of the Sierra Nevada Mountains to the 
north of California is called the Cascade Range, and is largely 
composed of voleanic rocks. It is on Mount Shasta, in the 
extreme northern portion of California, that we next find 
glaciers of any considerable size. But from this point on, 
glaciers multiply and continue, in ever-increasing glory, 
through the Coast Range of British Columbia and southern 
Alaska to the islands of the Aleutian Archipelago. 

' The glaciers upon Mount Shasta were first described by 
Mr. Clarence King in 1870. Previous explorers had as- 
cended the mountain upon the southern side, and reported it 
as free from glaciers, which are all upon the northern side. 
The most recent and detailed account of the glaciers on this 
mountain has been furnished by Mr. Gilbert Thompson, of 
the United States Geological Survey.t According to Thomp- 
son, Mount Shasta is a volcanic peak whose altitude above 
the sea is 14,511 feet. “It stands alone and has no connec- 
tion with neighboring mountains, none of which within a 
radius of forty miles attain two thirds its height.’ The 
mountain is a conspicuous object to attract attention for 
over a hundred miles. Five glaciers have been explored 
upon its northern flank, none of them, however, reaching 
lower than the 8,000-foot level, and none being more than 
three miles in length. 

The lower part of these glaciers is covered with vast 
quantities of earthy débrzs, so that it is difficult to tell where 
the ice-field now ends. It was from these half-buried edges 


* Russell, “ Existing Glaciers,” pp. 310-327. +t Ibid., pp. 832-534. 


16 THE ICE AGE IN NORTH AMERICA. 


of the ice-front on the flanks of Shasta that Mr. King drew 
the anaiogies which first solved the problem of the irregular 
gravel deposits forming the so-called kames and kettle-holes 
in New England, as above described.* Mr. King gives a 
thrilling account of how he at one time started such a move- 
ment of earth into one of the ice-tunnels, and came near 
himself falling into the yawning ice-chasm.t 

The following are the principal portions of Mr. King’s 
clear and vivid description of the glaciers on the north side 
of Mount Shasta: 


We reached the rim of the cone, and looked down into a 
deep gorge lying between the secondary crater and the main 
mass of Shasta, and saw directly beneath us a fine glacier, 
which started almost at the very crest of the main mountain, 
flowing toward us, and curving around the circular base of 
our cone. Its entire length in view was not less than three 
miles, its width opposite our station about four thousand feet, 
the surface here and there terribly broken in ‘‘ cascades,” and 
presenting all the characteristic features of similar glaciers else- 
where. The region of the terminal moraine was more extended 
than is usual in the Alps. The piles of rubbish superimposed 
upon-the end of the ice indicated a much greater thickness of 
the glacier in former days. After finishing our observations 
upon the side crater, and spending a night upon the sharp 
edge of its rim, on the following morning we climbed over 
the divide to the main cone, and up the extreme summit of 
Shasta. ... From the crest I walked out to the northern edge 
of a prominent spur, and looked down upon the system of 
three considerable glaciers, the largest about four and a half 
miles in length,{ and two to three miles wide. On the next 
day we descended upon the south side of the cone, following 
the ordinary track by which earlier parties have made the 
climb. From the moment we left the summit we encountered 


* Russell, “ Existing Glaciers,” p. 11. 

+ “ Proceedings of the Boston Society of Natural History,” vol. xix, p. 61. 

t These estimates prove to be somewhat exaggerated. Thompson gives the 
length of the Whitney Glacier, the longest on the mountain, as only 3,800 yards, 
less than two miles and a half. 


United States Geological Survey (Russell). 


rnia. 


Fi1a.. 13.—Mount Shasta, Califo 


18 THE ICH AGE IN NORTH AMERICA. 


less and less snow, and at no part of the journey were able to 
see a glacier. An east-and-west line divides the mountain 
into glacier-bearing and non-glacier-bearing halves. The as- 
cent was formerly always made upon the south side, where, 
as stated, there are no glaciers, and this is why able scientific 
observers like Professor Whitney and his party should have 
scaled the mountain without discovering their existence. . . . 

Upon reaching the eastern side we found in a deep cafion 
a considerable glacier, having its origin in a broad néve which 
reaches to the very summit of the peak. The entire angle 
of this glacier can be hardly less than twenty-eight degrees. 
It is one series of cascades, the whole front of the ice being 
crevassed in the most interesting manner. Near the lower end, 
divided by a boss of lava, it forks into two distinct bodies, one 
ending in an abrupt rounded face no less than nine hundred 
feet in height. Below this the other branch extends down 
the cafion for a mile and a half, covered throughout almost 
this entire length with loads of stones which are constantly fall- 
ing in showers from the cafion-walls on either side. Indeed, 
for a full mile the ice is only visible in occasional spots, where 
cavities have been melted into its body and loads of stones 
have fallen in. From an archway under the end a consider- 
able stream flows out, milky, like the water of the Swiss 
glacier-streams, with suspended sand. Following around the 
eastern base of Shasta, we made our camps near the upper 
region of vegetation, where the forest and perpetual snow touch 
each other. A third glacier, of somewhat greater extent than 
the one just described, was found upon the northeast slope of 
the mountain, and upon the north slope one of much greater 
dimensions. The exploration of this latter proved of very 
great interest In more ways than one. 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 fonr miles, reaching down the cafions between four and 
five miles, its lower edge dividing into a number of lesser ice- 
streams which occupy the beds of the cafions. This mass is 
sufficiently large to partake of the convexity of the cone, and, 
judging from the depth of the cafions upon the south and 
southeast slopes of the mountain, the thickness can not be less 


Puiate 1l—Geikie Glacier and Hanging Glacier on Mounts Fox and Dawson, British 
Columbia. (Photo by Canadian Topographical Survey.) 


GLACIERS ON THE PACIFIC CCAST. 19 


than from eighteen to twenty-five hundred feet. It is cre- 
yassed in a series of immense chasms, some of them two thou- 
sand feet long by thirty and even fifty feet wide. In one or 
two places the whole surface is broken with concentric systems 
of fissures, and these are invaded by a set of radial breaks 
which shatter the ice into a confusion of immense blocks. 
Snow-bridges similar to those in the Swiss glaciers are the 
only means of crossing these chasms, and lend a spice of 
danger to the whole examination. The region of the terminal 
moraines is quite unlike that of the Alps, a larger portion of 
the glacier itself being covered by loads of angular dédris. 
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 moulins 
nor regular dirt-bands are present. Numerous streams, how- 
ever, flow over the surface of the ice, but they happen to pour 
into crevasses which are at present quite wide. * 


From Mount Shasta to the Columbia River the moun- 
tains support many glaciers of thethirdorder. Mount Jef- 
ferson, Diamond Peak, and the Three Sisters are reported 
by Mr. Diller and Professor Newberry as containing numer- 
ous glaciers, and “‘as affording the most interesting field for 
glacial studies in the United States, with the exception of 
Alaska.” The glaciers upon Mount Hood have been more 
fully explored, and are of great interest, though, owing to 
the moderate elevation (11,000 feet) and the limited snow- 
fields, they are small in size. The summit of this mountain 
is occupied by a volcanic crater about half a mile in diameter. 
This serves as a fountain out of which there flow three 
. streams of ice extending down the flanks, as glaciers, for a 
distance of about two miles, their subglacial streams form- 
ing the head-waters of the White Sandy, and the Little 
Sandy Rivers. 

In the State of Washington, a short distance northof the 
Columbia River, the Cascade Mountains culminate in a clus- 


* “American Journal of Science,’’ vol. ci, 1871, pp. 158-161. 


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GLACIERS ON THE PACIFIC COAST. 21 


ter of peaks, with Mount Rainier, or, as it is coming to be 
ealled, Tacoma, as the center. This central peak is upward 
of 14,400 feet in height, and two or three neighboring peaks 
are upward of 10,000 feet. This great elevation, coupled 
with the higher latitude and the increasing moisture of the 
climate, favors the production of a most imposing series of 
glaciers. Even the passing traveler upon the railroad is 
made aware of their existence by the milky whiteness of the 
waters of the Cowlitz, the Nisqually, the Puyallup, and the 
White River, which are crossed on the way from Portland, 
Oregon, to Seattle in the State of Washington. All of these 
streams originate in glaciers far up on the flanks of the 
mountains to the east and south. 

Of this series, that on the north side of Mount Taco- 
ma, at the head of White River Valley, is the largest, and 


+ 
: 
i 


Fie. 15.—Mount Tacoma, looking eastward toward the summit, from Crater Lake. 


reaches down to within 5,000 feet of the sea-level. This 
glacier is about ten miles long, and, though comparatively 
narrow in its lower portion, is in places as muchas four 
miles wide. The extreme summit of the mountain has been 
ascended only by two or three parties, and the task is beset 
with such difficulties that it is not likely to be ascended 
often. Above the 9,000-foot level it is wholly enveloped in 
snow; while just below that limit, and close up to the realm 
of perpetual ice and snow, flowers make the air fragrant with 


992 THE ICE AGE IN NORTH AMERICA. 


their perfume, and the open spaces are gorgeous with their 
masses of brilliant color. 

The following is the description of the glaciers of this 
mountain cluster, as given by Mr. S. F. Emmons, of the 
United States Geological Survey, the first to ascend it: 


The main White River glacier, the grandest of the whole, 
pours straight down from the rim of the crater in a northeast- 
erly direction, and pushes its extremity farther out into the 
valley than any of the others. Its greatest width on the steep 
slope of the mountain must be four or five miles, narrowing 
toward its extremity to about a mile and a half; its length can 
be scarcely less than ten miles. The great eroding power of 
glacial ice is strikingly illustrated in this glacier, which seems 
to have cut down and carried away, on the northeastern side 
of the mountain, fully a third of its mass. The thickness of 
rock cut away—-as shown by the walls on either side—and the 
isolated peak at the head of the triangular spur . . . may be 
roughly estimated at somewhat over a mile. Of the thick- 
ness of the ice of the glacier I have no data for making esti- 
mates, though it may probably be reckoned in thousands of feet. 

It has two principal medial moraines, which, where crossed 
by us, formed little mountain-ridges, having peaks nearly one 
hundred feet high. The sources of these moraines are cliffs 
on the steeper mountain-slope, which seem mere black specks 
in the great white field above; between these are great cas- 
cades, and below, immense transverse crevasses, which we had 
no time or means to visit. The surface water flows in rills 
and brooks on the lower portion of the glacier, and moulins 
are of frequent occurrence. We visited one double moulin, | 
where two brooks poured into two circular wells, each about 
ten ieet in diameter, joined together at the surface but sepa- 
rated below ; we could not approach near enough the edge to 
see the bottom of either, but, as stones thrown in sent back 
no sound, judged they must be very deep. 

This glacier forks near the foot of the steeper mountain- 
slope, and sends off a branch to the northward, which forms a 
large stream flowing down to join the main stream fifteen or 
twenty miles below. Looking down on this from a high, over- 


GLACIERS ON THE PACIFIC COAST. 23 


hanging peak, we could see, as it were, under our feet, a little 
lake of deep, blue water, about an eighth of a mile in diameter, 
standing in the brown, gravel-covered ice of the end of the 
giacier. On the back of the rocky spur which divides these 
two glaciers, a secondary glacier has scooped out a basin-shaped 
bed, and sends down an ice-stream, having all the characteris- 
tics of a true glacier, but its ice disappears several miles above 
the mouths of the large glaciers on either side. Were nothing 
known of the movement of glaciers, an instance like this would 
seem to afford sufficient evidence that such movement exists, 
and that gravity is the main motive-power. From our north- 
ern and southern points we could trace the beds of several large 
glaciers to the west of us, whose upper and lower portions only 
were visible, the main body of the ice lying hidden by tke high 
intervening spurs. 

Ten large glaciers observed by us, and at least half as 
many more hidden by the mountain from our view, proceeding 
thus from an isolated peak, form a most remarkable system, 
and one worthy of a careful and detailed study.* 

Still farther to the north, in the State of Washington, 
Mount Baker, rising to an elevation of 11,000 feet, is to a 
limited extent a center for the dispersion of glaciers of small 
size. The field, however, has been but imperfectly explored. 

Northward from the State of Washington the coast is 
everywhere very rugged, being formed by the lofty peaks of 
an extension of the Cascade Range; while the thousands of 
islands which fringe the coast of British Columbia and Alaska 
are but the partially submerged peaks of an extension of the 
Coast Range, from which the great glaciers of former times 
have scraped off nearly all the fertile soil. It is estimated 
that there are ten thousand islands between the State of 
Washington and Mount St. Elias, and all the larger of them 
bear snow-covered summits during the whole year. The water 
in the narrow channels separating these islands is ordinarily 
several hundred feet deep, affording, through nearly the 
whole distance, a protected channel for navigation. 


* Quoted by Clarence King, in the ‘“‘American Journal of Science,” 
vol. ci, pp. 164, 165. 


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The arrow-points mark glaciers. 


Fic. 16.—Map of Southeastern Alaska. 


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GLACIERS ON THE PACIFIC COAST. 20 


Three great rivers interrupt the mountain barrier of 
British Columbia facing the Pacific—the Fraser, the Skeena, 
and the Stickeen—and the interior is penetrated for some 
distance by innumerable fiords. The Canadian Pacific Rail- 
road follows the course of the Fraser for a long distance, and 
passes within sight of glaciers of considerable extent, and 
every fiord receives the drainage of numerous decaying gla- 
ciers. But it is not until reaching the Stickeen River, in 
Alaska, in latitude 57°, that glaciers begin to appear which 
are both easily accessible and large enough to invite pro- 
tracted study. The water coming into the sound from the 
Stickeen River is heavily charged with glacial mud, which 
spreads itself out over a great expanse. An extensive celta, 
forming almost the only arable land in southeastern Alaska, 
has been built up by the deposit at the mouth of this river. 
The earliest accurate information obtained concerning these 
glaciers is that gathered by Mr. William P. Blake in 1863. 
According to him, “there are four large glaciers and several 
smaller ones visible within a distance of sixty or seventy miles 
from the mouth” of the river. The second of these larger 
ones has attracted most attention. This “sweeps grandly 
out into the valley from an opening between high mountains 
from a source that is not visible. It ends at the level of the 
river in an irregular bluff of ice, a mile and a half or two 
miles in length, and about one hundred and fifty feet high. 
Two or more terminal moraines protect it from the direct 
action of the stream. What at first appeared as a range of 
ordinary hills along the river, proved on landing to be an 
ancient terminal moraine, crescent-shaped, and covered with 
a forest. It extends the full length of the front of the 
glacier.” * 

This glacier presents many difficulties to explorers. A 
small party of Russian officers once attempted its explora- 
tion, and were never heard from again. Mr. Blake re- 
ports that, as usual with receding glaciers, a considerable 


* “American Journal of Science,’’ vol. xciv, 1867, pp. 96-101. 


- Casprayieg &q ydevisojoyg) 
*OpIM O[IU OUO JNOGB JO “JUOIJ OY} WOA JO VOYOIG AVY YVYY So10QooI SuIMOYS “BYSeLY “Jo[Ul NyVY, “OLOV[H SIMION—"LT “Ol 


GLACIERS ON THE PACIFIC COAST. m7 


portion of the front as it spreads out in the valley is so coy- 
ered with bowlders, gravel, and mud that it is difficult to tell 
where the glacier really ends. But from the valley to the 
higher land it rises in precipitous, irregular, stair-like blocks, 
with smooth sides, and so large that it was impossible to sur- 
mount them with the ordinary equipment of explorers. The 
glacier is estimated to be about forty miles long. 

Another glacier, upon the opposite side of fhe river, of 
which Mr. Blake does not speak, was reported to me by those 
familiar with the country as coming down to within about 
two miles of the bank. The Indians are very likely correct 
in asserting that these two glaciers formerly met, compelling 
the Stickeen River to find its way to the sea through a vast 
tunnel. It would then have appeared simply as a subglacial! 
stream of great magnitude. 

North of the Stickeen River, glaciers of great size are of 
increasing frequency, and can be seen to good advantage 
from the excursion-steamer. The Auk and Patterson gla- 
ciers appear first, not far north of Fort Wrangel. On 
approaching Holkham Bay and Taku Inlet, about latitude 
58°, the summer tourist has, in the numerous icebergs en- 
countered, pleasing evidence of the proximity of still greater 
glaciers coming down to the sea-level. Indeed, the glaciers 
of Taku Inlet are second only in interest to those of Glacier 
Bay, hereafter to be described more fully. 

In going from Juneau to Chilkat, at the head of Lynn 
Canal, a distance of about eighty miles, nineteen glaciers of 
large size are in full sight from the steamer’s deck, but 
none of them come down far enough to break off into the 
water and give birth to icebergs. The Davidson Glacier, 
however, comes down just to the water’s edge, and has there 
built up an immense terminal moraine all along its front. 

An illustration of the precipitous character of the south- 
eastern coast of Alaska is seen in the fact that it is only 
thirty-five miles from the head of Lynn Canal to the sources 
of the Yukon River, which then flows to the north and west 
for nearly three thousand miles before coming down to the sea- 


ie 
AN 
co 


\} 


a anti! 
ie 


mar 


Fig. 18.—Glacier Station, Selkir 


British Columbia. (Courtesy of the Canadian Pacific Railroad.) 


k Mountains, 


GLACIERS ON THE PACIFIC COAST. 29 


level. Lieutenant Schwatka reports four glaciers of consider- 
able size in the course of this short portage between Chilkat 
and Lake Lindeman.* The vast region through which the 
Yukon flows to the north of these mountains is not known 
to contain any extensive glaciers. But the ground remains 
perpetually frozen at a short depth below the surface. Russell 
reports that in many places cliffs of ice abut upon the border 
of the Yukon on whose surface is a sufficient depth of soil 


Fie. 19.—Davidson Glacier, near Chilkat, Alaska, latitude 59° 45’. The mountains are 
from five thousand to seven thousand feet high ; the gorge about three quarters of 
a mile wide ; the front of the glacier, three miles; the ‘terminal moraine, about two 
hundred and fifty feet high. (View from two miles distant.) 


to support dense evergreen forests. Since the discovery of 
gold in the region a considerable population has entered, and 
certain forms of agriculture have begun to flourish. 

From Cross Sound, about latitude 58° and longitude 136° 
west from Greenwich, to the Alaskan Peninsula, the coast is 
bordered by a most magnificent semicircle of mountains, 
opening to the south, and extending for more than a thousand 
miles. Throughout this whole extent, glaciers of large size 


* “Science,” vol. iii (February 22, 1884), pp. 220-227. 


30 THE ICE AGE IN NORTH AMERICA. 


are everywhere to be seen. Elliott estimates that, count- 
ing great and small, there can not be less than five thousand 
glaciers between Dixon’s Entrance and the extremity of the 
Alaskan Peninsula. 


The glaciers in the vicinity of Mt. St. Elias are the largest 
anywhere to be found on the continent. Numerous single 
glaciers, of which Seward is the largest, come down from the 
mountain range and, becoming confluent, unite to form the 
Malaspina glacier. This is a plateau of ice about 1,500 feet 
in height stretching all along the southern base of the St. 
Elias range for a distance of fifty miles, and covering an 
area of about a thousand square miles. In Icy Bay the gla- 
cier, comes down to sea-level, presenting a solid wall many 
miles in extent, which is continually breaking off into ice- 
bergs of great size. Far out upon the surface large forests 
occur surrounded by glacial ice. These are supported upon 
deep beds of gravel and sand which have been carried out by 
mountain streams whose channels have changed from time 
to time with the varying conditions of the surface of the ice. 
Lakes of considerable size are also found upon the surface 
at an altitude as high as 5,000 feet, with streams flowing 
between the ice and the mountain side, illustrating, possibly, 
the origin of many terraces of gravel on the flanks of moun- 
tains in the glaciated region of the United States. Such are 
to be noted on the flanks of both the Green and the Adiron- 
dack mountains, deposited originally on the sides of the mass 
of ice that filled the Champlain Valley. 


The glaciers of the St. Elias range are, however, mostly 
confined to the south side which is exposed to the sea breezes. 
Schwatka and Hayes who in 1892 made the tour of the 
range, coming out at Copper River, found the country free 
from glaciers and the climate so dry that they could comfort- 
ably sleep out of doors. 


The glaciers about the upper end of Yakutat Bay are of 
special interest because of the recent changes which have 


GLACIERS ON THE PACIFIC COAST. 31 


taken place in them. The narrowing upper portion of the 
bay which is now bordered by the gravel deposits of the gla- 
cial streams pouring out from the southeastern portion of 
the Malaspina Glacier is called Disenchantment Bay. But 
above Haenke Island the depression turns at right angles 
sharply to the south and extends twenty-five miles between 
mountain ranges forming Russell Fiord. Into this fiord 


& 
“ — * Submerg 
*, « marking recent 
— _ =~ -great advance (?) 


— bea 


NX 2 q ae 
‘ % ae , 
a Fa _—<ih 40 
Mecminu 2 of last reat _ 
ve 4 \s 


advance 


Ss ° 5 10 15 MILES 
ee ee ee eee ee ee 


Fie. 20—Map showing hypothetical former extension of glaciers during ice-flood stage, 
based on observations of the height reached by the glaciers at a number of points. 
(From U.S. Geological Survey.) 


numerous local glaciers descend from both sides. The evi- 
dence is clear that at a comparatively recent time, probably 
as late as the visit of Vancouver near the close of the 18th 


: Es 


32 THE ICE AGE IN NORTH AMERICA. 


century, the Malaspina Glacier, and others near its south- 
eastern border, had advanced so as to completely fill Disen- 
chantment Bay and transform Russell Fiord into a long nar- 
row lake, dammed up by the ice at the mouth of the bay. 
According to Tarr,* the evidences of this recent advance are 
abundant in the moraines that were pushed up on the moun- 
tain slopes east of Yakutat Bay. But, for some time previous 
to 1905, a recession had been in progress along the front of 
all the separate glaciers into which the original confluent 
glacier had been resolved by the general retreat. Thus he 
writes: 


There is a remarkable change in progress in at least 
four of the many valley glaciersof the Yakutat Bay region— 
the Variegated, Haenke, Atrevida,and Marvine. This change 
is of the nature of a paroxysmal thrust, as a result of 
which the ice is badly broken, as if a push from behind had 
been applied with such vigor as to break the rigid resisting 
ice mass in front. In each case the effect of this thrust is 
felt from far up the mountain valley well down toward the 
terminus of the glacier, and in the Haenke and Marvine 
glaciers to their very end. 

In Variegated and Atrevida glaciers the ice has been 


broken for a distance of five to seven miles: in Marvine 


glacier the breaking extends fully fifteen miles. The crevassing 
in all cases extends completely across the valley portion of 
the glacier and down into the stagnant, or nearly stagnant, 
moraine-covered margin. In all cases, too, the thrust is 
accompanied bya forward movement of the margin; and in 
at least three cases—the Variegated, Haenke, and Atrevida— 


there has been a distinct thickening of the ice as a result of 


the forward thrust. . . . Such a remarkable change 
in the condition of the glaciers as to transform long-stag- 
nant, unbroken, moraine-covered valley glaciers into a laby- 
rinth of crevasses in the short interval of ten months—a 
phenomenon, so far as known, not elsewhere recorded—calls 
for a special explanation. 


*“United States Geological Survey, Professional Paper” 64, pp. 91-106. 


7 


(Photo by Russell.) 


Pirate IV—Forest growing on top of the front of Malaspina Glacier, Alaska. 


GLACIERS ON THE PACIFIC COAST. 33 


Professor Tarr attributes this remarkable advance tothe 
effect of the earthquake which occurred in the region in 1899, 
six years before. This earthquake, which was sufficient to 
elevate a portion of the coast forty-seven feet, he supposes to 
have shaken large quantities of snow down from the more 
elevated peaks upon the head of the glaciers, and that it 
took all the intervening six years to make its influence felt 
at the margin. Thus, as the weather bureau, when the extent 
of the rainfall at the sources of a great river is known, can. 
predict when the swollen current will reach successive points 
along the river valley, so the glacialist can foretell, from the 
- snow-fall over the névé, when its influence will be felt below 
through the more resisting medium of the glacial ice. 

The suddenness with which this advance began and the 
vigor with which it went forward afford an interesting com- 
mentary upon the prevailing notions entertained concerning 
the “uniformity of nature’s operations,” and make it easier 
for us to credit the vast changes which appear to have taken 
place in this region since Vancouver’s visit in the latter part 
of the 18th century. 

Vancouver’s account of the glacial phenomena along this 
coast is still both instructive and interesting, and in places 
curious. | 


Between these points [Pigot and Pakenham] a bay is 
formed, about a league and a half deep toward the north- 
northwest, in which were seen several shoals and much ice ; 
the termination of this bay is bounded by a continuation of 
the above range of lofty mountains. On this second low pro- 
jecting point, which Mr. Whidbey called ‘‘ Point Pakenham,” 
the latitude was observed to be 60° 594’, its longitude 212° 29’. 
The width of the arm at this station was reduced to two miles, 
in which were several half-concealed rocks, and much floating 
ice, through which they pursued their examination, to a point 
at the distance of three miles along the western shore, which 
still continued to be compact, extending north 30° east; in 
this direction they met such innumerable huge bodies of ice, 
some afloat, others lying on the ground near the shore in ten 


GLACIERS ON THE PACIFIC COAST, — 30 


or twelve fathoms water, as rendered their further progress 
up the branch rash and highly dangerous. This was, however, 
very fortunately, an object of no moment, since before their 
return they had obtained a distinct view of its termination, © 
about two leagues farther in the same direction, by a firm and 
compact body of ice reaching from side to side, and greatly 
above the level of the sea; behind which extended the con- 
tinuation of the same range of lofty mountains, whose summits 
seemed to be higher than any that had yet been seen on the coast. 

While at dinner in this situation they frequently heard a 
very loud, rumbling noise, not unlike loud but distant thun- 
der ; similar sounds had often been heard when the party was 
in the neighborhood of large bodies of ice, but they had not 
before been able to trace the cause. They now found the 
noise to originate from immense ponderous fragments of ice, 
breaking off from the higher parts of the main body, and fall- 
ing from a very considerable height, which in one instance 
produced so violent a shock that it was sensibly felt by the 
whole party, although the ground on which they were was 
at least two leagues from the spot where the fall of ice had 
taken place... . 

The base of this lofty range of mountains [between Elias 
and Fairweather], now gradually approached the sea-side ; 
and to the southward of Cape Fairweather it may be said 
to be washed by the ocean ; the interruption in the sum- 
mit of these very elevated mountains, mentioned by Captain 
Cook, was likewise conspicuously evident to us as we sailed 
along the coast this day, and looked like a plain composed of a 
solid mass of ice or frozen snow, inclining gradually toward 
the low border; which, from the smoothness, uniformity, 
and clean appearance of its surface, conveyed the idea cf ex- 
tensive waters having once existed beyond the then limits of 
our view, which had passed over this depressed part of the 
mountains, until their progress had been stopped by the 
severity of the climate, and that, by the accumulation of suc- 
ceeding snow, freezing on this body of ice, a barrier had become 
formed that had prevented such waters from flowing into the 
sea. This is not the only place where we had noticed the like 
appearance : since passing the icy bay mentioned on the 28th 


36 THE ICK AGE IN NORTH AMERICA, 


of June, other valleys had been seen strongly resembling this, 
but none were so extensive, nor was the surface of any of them 
so clean, most of them appearing to be very dirty. I do not, 
however, mean to assert that these inclined planes of ice must 
have been formed by the passing of inland waters thus into 
the ocean, as the elevation of them, which must be many 
hundred yards above the level of the sea, and their having 
been doomed for ages to perpetual frost, operate much against 
this reasoning ; but one is naturally led, on contemplating any 
phenomenon out of the ordinary course of nature, to form 
some conjecture, and to hazard some opinion as to its origin, 
which on the present occasion is rather offered for the purpose 
of describing its appearance, than accounting for the cause of 
its existence. * | 

Westward from Mt. St. Elias the lofty semicircular ranges 
culminating in Mount Wrangell and Mount McKinley, both 
of which attain an elevation of 20,000 feet (the former being 
a live voleano), abound with glaciers beside which those of 
the Swiss Alps would seem insignificant. While from the 
flanks of the Chugatch Range immense streams of ice descend 
to Prince William Sound, and add greatly to the gloomy gran- 
deur of its scenery. Glaciers are also numerous in the Kenai 
and Alaskan peninsulas as far to the westward as longitude 
162°, and one even has been observed upon the island of 
Unalaska. 

Beyond these ranges the broad valleys of the Kuskovim 
and the Yukon rivers are chiefly characterized by sparsely 
covered timber areas and tundras in many respects similar to 
the Arctic litoral of Siberia, where the soil is frozen to a 
great depth, the heat of the short summer being able to melt 
scarcely more than a few inches below the surface, sections in 
many places showing alternate layers of earth and pure ice. 
In Alaska, however, a few glaciers again appear in the high- 
lands of the far north. 

At Eschscholtz Bay, on Kotzebue Sound, in latitude 66° 


*“WVoyage of Discovery around the World,”’ vol. v, pp. 312-314, 358-360. 


ALEUTIAN ISLANDS | 


SCALE OF MILES 


PHYSICAL MAP OF 


ALASKA 
hy 


ER Onan 6 ~ == ae SCALE OF MILES 

ae ee \ Ne : 5 cS (1) 200 300 
oy ae REFERENCE 
uk Ae 


ALTITUDES IN FEET. OCEAN DEPTHS IN FEET. 
Oto 500, Very Low Plains, | 4 Oto 600 
|__| 500t0 1,000, Higher Plains, |__| 600t0 6,000 
| _|1,000to 5,000, Plateaus. |__| 6,000 to 12,000 
|__| 6,000 to 10,000, Summits. | | 12,000 to 48,000 
Over 10,000, Highest Summits, Over 48,000 


Warm Currents 
Glaciers w 


Elias 
St 100 


af 2SNOCHEK 
z De KAYAK me o eo 
NTAGUE. 1 th 


=g00 Ft 
“64, 


: 7 BARREN 1. 
YC. Douglas © 


sf 
= = SUTKHOON 


Greenwich 


GLACIERS ON THE PACIFIC COAST. od 


15’, Kotzebue discovered in 1818 a cliff of frozen mud and 
ice “capped by a few feet of soil bearing moss and grass.” * 
Large number of bones of the “ mammoth, bison (?), rein- 
deer, moose-deer, musk-ox, and horse, were found” at the base, 
where they had fallen down from the cliff durmg the summer 
thaws. Sir Edward Belcher and Mr. G. B. Seeman after- 
ward visited the same spot and corroborated Kotzebue’s ac- 
count. From their report it was evident that the conditions 
in northern Alaska are very similar to those in northern Si- 
beria, where so many similar remains of extinct and other 
animals have been found in the frozen soil. The section de- 
scribed at Eschscholtz+Bay seems to be simply the edge of 
the tundra which is so largely represented in the central 
portions of the Territory. In 1880 Mr. Dall visited the local- 
ity and gave a fuller description than had been before given. 
The conditions are so unique that we reproduce his account : 


The ice-cliffs at this point were for a considerable distance 
double ; that is, there was an ice-face exposed near the beach 
with a small talus in front of it and covered with a coating of 
soil two or three feet thick, on which luxuriant vegetation was 
growing. All this might be thirty feet in height. On climb- 
ing to the brow of this bank the rise from that brow proved to 
be broken, hummocky, and full of crevices and holes; in fact, 
a second talus on a larger scale, ascending to the foot of a sec- 
ond ice-face, above which was a layer of soil one to three feet 
thick covered with herbage. 

The brow of this second bluff we estimated at eighty feet or 
more above the sea. Thence the land rose slowly and gradu- 
ally to a rounded ridge, reaching the height of three or four 
hundred feet only at a distance of several miles from the sea, 
with its axis in a north-and-south direction, a low valley west 
from it, the shallow bay at Elephant Point east from it, and 
its northern end abutting inthe cliffs on the southern shore of 
Eschscholtz Bay. There were no mountains or other high 
land about this ridge in any direction ; all the surface around 
was lower than the ridge itself. 


4 


* See Prestwich’s “ Geology,” vol. ii, p. 463 e seq. 


38 THE ICH AGE IN NORTH AMERICA. 


About half a mile from the sea, on the highest part of the 
ridge, perhaps two hundred and fifty feet above high-water 
mark, at a depth of a foot, we came to a solidly frozen stratum 
consisting chiefly of bog-moss and vegetable mold, but con- 
taining good-sized lumps of clear ice. ‘There seemed no reason 
to doubt that an extension of the digging would have brought 
us to solid clear ice such as was visible at the face of the bluff 
below ; that is to say, it appeared that the ridge itself, two 
miles wide and two hundred and fifty feet high, was chiefly 
composed of solid ice overlaid with clay and vegetable mold. - 

The ice in general had a semi-stratified appearance, as if it 
still retained the horizontal plane in which it originally con- 
gealed. The surface was always soiled by dirty water from the 
earth above. This dirt was, however, merely superficial. The 
outer inch or two of the ice seemed granular, like compacted 
hail, and was sometimes whitish. The inside was solid and 
transparent or slightly yellow-tinged, lke peat- water, but 
never greenish or bluish like glacier-ice. But in many places 
the ice presented the aspect of immense cakes or fragments 
irregularly disposed, over which it appeared as if the clay, etc., 
had been deposited. Small pinnacles of ice ran up into the 
clay in some places, and, above, holes were seen in the face of 
the clay bank,. where it looked as if a detached fragment of ice 
had been melted out, leaving its mold in the clay quite perfect.* 


After speaking of the frequency with which tbe bones of . 
the mammoth and buffalo and other animals are found, and 
of portions of the earth which still has in it the odor of the 
decaying flesh, Dr. Dall adds : 


Dwarf birches, alders seven or eight feet high, with stems 
three inches in diameter and a luxuriant growth of herbage, 
including numerous very toothsome berries, grew with the 
roots less than a foot from perpetual solid ice. 

The formation of the surrounding country shows no high 
land or rocky hills, from which a glacier might have been 
derived and then covered with dédris from their sides. The 
continuity of the mossy surfacé showed that the ice must be 


* “ American Journal of Science,” vol. exxi, 1881, pp. 106-109. 


GLACIERS ON THE PACIFIC COAST. 39 


quite destitute of motion, and the circumstances appeared to 
point to one conclusion, that there is here a ridge of solid ice 
rising several hundred feet above the sea and higher than any 
of the land about it and older than the mammoth and fossil 
horse, this ice taking upon itself the functions of a regular . 
stratified rock. The formation, though visited before, has not 
hitherto been intelligibly described from a geological stand- 
point. Though many facts may remain to be investigated, 
and whatever be the conclusions as to its origin and mode of 
preservation, it certainly remains one of the most wonderful 
and puzzling geological phenomena in existence. 


The same author elsewhere writes that the continuity of 
this deposit “is broken between Kotzebue Sound and Icy 
Cape by rocky hills composed chiefly of carboniferous lime- 
stones, which bear no glaciers, and do not seem to have been 
glaciated. The absence of bowlders and erratics over all this 
area has been noted by Franklin, Beechy, and all others who 
have explored it.” * 

During the period of the Russian occupancy of Alaska 
scarcely anything was added to our knowledge of its glaciers 
further than what is to be found in the notes of Vancouver’s 
voyage., Even the existence of Glacier Bay, which is to 
form the subject of the next chapter, was not suspected till a 
comparatively recent time, and it is not noted on any map 
drawn previous to 1880. Muir Glacier, which is now the 
object of greatest interest to the host of summer tourists who 
crowd the steamers making the round trip from Portland, 
Oregon, through the waters of southeastern Alaska, was 
brought to the notice of the outside world by the California 
gentleman whose name it bears, as late as 1879, when he and 
Rey. Mr. Young, of the Presbyterian mission at Fort Wran- 
gel, made a voyage of discovery around the archipelago in 
a dug-out canoe. 


*“ Bulletin of the Philosophical Society of Washington,” vol. vi, p. 33; 
quoted in Russell, as above, p. 354. 


CHAPTER Ill. 


A MONTH WITH THE MUIR GLACIER. 


In the summer of 1886 a party of three, consisting of 
Rey. J. L. Patton, Mr. Prentiss Baldwin, and myself, ar- 
ranged to visit the Muir Glacier, at the head of Glacier 
Bay in Alaska, for the purpose of collecting facts concerning 
its motion, its size, its present general condition, and its 
probable past history and future career. The present chapter 
will detail with some minuteness the results of our observa- 
tion. 

On the 4th of August, in company with two Indians for 
assistants, we were landed by the excursion-steamer on the 
east side of the inlet, directly in front of the Muir Glacier, 
with a dug-out canoe as our only means of escape, and two 
canvas tents as our only shelter. Here we remained a whole 
month, or until September 2d, while the steamer made a round 
trip to Portland, Oregon, and returned with another load of 
freight and tourists. The region is the most desolate imagi- 
nable. Indians rarely navigate its upper waters, and it is 
visited only by the steamer to allow tourists to behold for a 
few hours the wonderful spectacle of a stream of ice more 
than a mile in width, and four hundred feet in height, moy- 
ing onward with irresistible force to meet the equally irre- 
sistible waters of a deep tidal inlet. Those who have here, 
for a few hours only, witnessed the “calving” of icebergs, 
and heard the detonations preceding and accompanying the 
falling of the masses from the ice-front, can never forget the 
scene. Much less can we forget it, who spent a month im 
the majestic presence of the mighty glacier. _ 


A MONTH WITH THE MUIR GLACIER. 4] 


Our facilities for observations were limited by several 
unfavorable conditions. In the first place, though we were 
there in the dry season, fifteen of the twenty-nine days 
were so rainy that it was impossible to stir out of our tents 
or to see far through the mists. In the second place, 
the tides were so strong, and the winds at times so vio- 
lent, that it was hazardous to venture far away with our 
canoe. In the next place, the surface of the glacier is, in 
its central portion, so intersected by yawning crevasses that 
it was entirely out of the question to attempt to cross 
it. Plans for measurement, different from those made 
familiar in Professor Tyndall’s book, had therefore to be 
devised. 

On the other hand, soie things were favorable to obtain- 
ing satisfactory results. The fourteen days of fair weather 
were extremely clear and beautiful, and there are no trees 
upon the mountains to obstruct one’s view or to hinder him 
in rambling over them. 

The specitic results as to the movements of the ice, and 
as to the formation of moraines and kames, are told a little 
later. Here a few words will be in place concerning the 
general aspect of the region as we saw it in August. 

The mountains on each side of Muir Inlet rise immedi- 
ately from the water from three thousand to five thousand 
feet. These we often ascended, and thus were permitted 
repeatedly to behold one of the most marvelous views any- 
where to be found in the world. At that season the level 
places around our feet upon these summits were carpeted 
with soft green grass, interspersed with large areas of tlow- 
ers in full bloom. Here were extensive, gorgeously colored 
flower-beds, where bluebells, daisies, buttercups, violets, the 
yellow arnica-flower, and the purple epilobium, were striv- 
ing for mastery or for recognition. On the northern slopes 
of slight elevations great masses of snow were preserved 
in the very midst of these brilliant flower - gardens, and, 
from their melting, clear little pools of water were on 
every hand inviting us to drink. The track of the mount- 


42 THE ICE AGE IN NORTH AMERICA. 


ain goat, the mountain lion, and of various smaller animais, 
and the songs of birds, witnessed to the abundance of ani- 
mal life. 

To the south the calm surface of the bay opened outward 
into Cross Sound, twenty-five miles away. The islands dot- 
ting the surface of the smooth water below us seemed but 
specks, and the grand vista of snow-clad mountains, guarding 
either side of Chatham Strait, seemed gradually to come to 
a point on the southern horizon. Westward, toward the 
Pacitic, was the marvelous outline of the southern portion 
of the St. Elias Alps. The lofty peaks of Crillon (15,900 
feet high) and Fairweather (15,500 feet high), about twenty- 
tive miles away, and about the same distance apart, stood as 
sentinels over the lesser peaks, La Pérouse, Lituya, and 
their companions, which, anywhere else, would appear to be 
mountains of the first class, being more than ten thousand 
feet high, and rising directly from the water's edge. At 
one time, when on a summit overlooking Glacier Bay, it was 
our good fortune to see the sun go down behind this mount- 
ain-chain. Alternate shadows and golden rays of setting 
sunlight stretched across the water and climbed the peak on 
which we stood. The glistering summits of the western 
mountains were lined with the same glowing colors, while 
the solemn procession of glaciers on their eastern flanks was 
gradually fading in the growing darkness, and the more dis- 
tant mountain-tops in other directions were ceasing to reflect 
the glow of the western horizon. 

Tn such a setting of grandeur and beauty we gazed upon 
the full face of the great glacier itself lying at our feet. 
Below us its diminishing outlet disappeared in the waters of 
the bay. Distance made the rough places plain, and lent 
enchantment to the view. Down from the mountains in 
every direction from the north came the frozen torrents: 

Glaciers to the right of us, 

Glaciers to the left of us, 

Glaciers in front of us, 
Volleyed and thundered— 


= — . 


A MONTH WITH THE MUIR GLACIER. 43 


pouring into a vast amphitheatre, and then uniting their vol- 
ume, preparatory to their exit through the entrance into Muir 
Inlet. These numerous local glaciers united to form nine 
main streams whose individuality could be determined all 
across the amphitheatre by the long lines of medial moraines 
which swept around in majestic curves from every quarter, 
like great railroad embankments in approaching some grand 
central depot. Such is a faint description of the scene upon 
which we gazed. Strength and beauty were here united as 
probably nowhere else in the world. But the shades of night 
slowly fell upon us, even in that high latitude, and we were 
compelled to come down closer to the thundering noises of 
the active glaciers and seek the prosaic quarter of our tents, 
and to go about the more detailed investigation of the mar- 
velous phenomena before us. The results I will now pro- 
ceed to give. 

The Muir Glacier enters an inlet of the same name at the 
head of Glacier Bay, in latitude 58°.50’, longitude 136° 40’, 
west of Greenwich (see Fig. 22). This bay is a body of 
water about thirty miles long, and from eight to twelve miles 
wide (but narrowing to about three miles at its upper end), 
projecting in a northwest direction from the eastern end of 
Cross Sound. The promontory separating it from the Pacif- 
ic Ocean is from thirty to forty miles wide, and contains 
the lofty mountain-peaks of Crillon, Fairweather, Lituya, 
and La Pérouse, whose heights have already been indicated. 
To the east, between Glacier Bay and Lynn Canal, is a pen- 
insula, extending considerably south of the mouth of the 
bay, and occupied by the White Mountains, probably having 
no peaks exceeding ten thousand feet. 

Near the mouth of Glacier Bay is a cluster of low isl- 
ands named after Commander Beardslee, of the United 
States Navy. There are twenty-tive or thirty of these, and 
they are composed of loose material—evidently glacial débrzs 
—and are in striking contrast with most of the islands and 
shores in southeastern Alaska. These, also, like all the other 
land to the south, are covered with evergreen forests, though 


44 THE ICE AGE IN NORTH AMERICA. 


1 eS 
<a WHS S<Ce 


pots 
TAN OTR 
Gr Ww 


SS 


A 


AQ IN 


5 SWVOS,/ 


pit Ee) 3 

CG, My 

lei: 
EE 


Y2I0y7 


ISLANDS © 
gFRANCIS I. 
WILLOUGHBY, |. 


4p » 
z Mn, 
SSE A Se 
< aq DNS y A 
A | ey 
| Lea = 
aes fae. ~ . 
er ie 
= > . 
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SKETCH MAP OF 
GLACIER BAY AND MUIR GLACIER 
By HARRY FIELDING REID. 


a , A 
A ‘Gustavus 
F MILE 

SCALE 2 ILES Icy Strait 

0 Svea 10 vir 
136° 30’ 


136° 


Hire, 22: 


the trees are of moderate size; but the islands and shores in 
the upper part of the bay are entirely devoid of forests. 
Willoughby Island, near the middle of the bay, is a bare 
rock, about two miles long and fifteen hundred feet high, 
showing glacial furrows and polishing from the bottom to 
the top. Several other smaller islands of similar character 
in this part of the bay show like signs of having been re- 
cently covered with glacial ice. 


The upper end of the bay is divided into two inlets of 


a “VT ee eS Lh ee 


i - 


— 


a eee a, ae 


ae a Se 


- 


A. MONTH WITH THE MUIR GLACIER. 45 


unequal lengths, the western one being about four miles 
wide, and extending seven or eight miles (estimated) in the 
direction of the main axis of the bay to the northwest. The 
eastern, or Muir Inlet, is a little over three miles wide at its 
mouth, and extends to the north about the same distance, 
narrowing, at the upper end, to a little over one mile, where 
it is interrupted by the front of the Muir Glacier. The real 
opening between the mountains, however, is here a little over 
two miles wide, the upper part on the eastern side being oc- 
cupied with glacial débris covering a triangular space be- 
tween the water and the mountain about one mile wide at 
the ice-front and coming to a point three miles below, be- 
yond which a perpendicular wall of rock one thousand feet 
high rises directly from the water. The mountain on the 
west side of Muir Inlet, between it and the other fork of the 
bay, is 2,900 feet high. That on the east is 3,150 feet high, 
rising to about 5,000 feet two or three miles back. The base 
of these mountains consists of metamorphic slate, whose strata 
are very much contorted—so much so that it is difficult to 
ascertain their system of folds. Upon the summits of the 
mountains on both sides are remnants of blue crystalline 
limestone preserved in synclinal axes. In the terminal mo- 
raine deposited in front of the glacier on its eastern side are 
numerous bowlders of very pure white marble brought down 
in medial moraines from mountain valleys several miles to 
the east. Granitic bowlders are also abundant. 

The width of the ice where the glacier breaks through 
between the mountains is 10,664 feet—a little over two 
miles. But, as before remarked, the water-front is only 
about one mile. This front does not form a straight line, 
but terminates in an angle projecting about a quarter of a 
mile below the northeast and northwest corners of the inlet. 
The depth of the water three hundred yards south of the ice- 
front is (according to the measurement of Captain Hunter, 
of the steamer Idaho) 516 feet near the middle of the chan- 
nel; but it shoals rapidly toward the eastern shore. A meas- 
urement reported to me by Dr. Jackson, made in July, 


Q88T “JULISIP sojrur FT ‘oroys oy1s0ddo ’ 
10 [OARIF PUL PULS POYT}eI}S FULP]IIOAO 99} PUT PUNOIFE10} UT OULEIOUT SurMoys ‘VyselV 


‘JOPIVT) IMJ JO JUOIJ ss010e FUyYOOT—¢z “OT 


| ieee 


A MONTH WITH THE MUIR GLACIER. 47 


1887, with the prow of the steamer within twenty feet of 
the ice-front, is one hundred and six fathoms (636 feet), and 
no bottom. According to my measurements, taken by level- 
ing up on the shore, the height of the ice at the extremity 
of the projecting angle in the middle of the inlet was 250 
feet, and the front was perpendicular. Back a few hun- 
dred feet from the projecting point, and along the front 
nearer the shores, the perpendicular face of the ice was a lit- 
tle over 300 feet. A little farther back, on a line even with 
the shoulders of the mountains between which the glacier 
emerges to meet the water, the general height is 408 feet. 
From here the surface of the glacier rises toward the east and 
northeast about 100 feet to the mile. On going out in that 
direction on the ice seven miles (as near as I could estimate), 
I found myself, by the barometer, 1,050 feet above the bay. 

The main body of the glacier occupies a vast amphithea- 
tre, with diameters ranging from thirty to forty miles. This 
estimate was made from various views obtained from the 
_mountain-sunmits near its mouth, when points whose dis- 
tances were known in other directions were in sight. Nine 
main streams of ice unite to form the grand trunk of the 
glacier. These branches come from every direction north 
of the east-and-west line across the mouth of the glacier ; 
and no less than seventeen sub-branches can be seen coming 
in to join the main streams from the mountains near the rim 
of the amphitheatre, making twenty-six in all. Numerous 
rocky eminences also rise above the surface of the ice, like 
islands from the sea, corresponding to what are called nuna- 
taks in Greenland. The two of these visited, situated about 
four miles back from the front, showed that they had been 
recently covered with ice—their surfaces being smoothed 
and scored, and glacial débris being deposited everywhere 
upon them. Upon the side from which the ice approached 
. these islands (the stoss side) it rose, like breakers on the sea- 
shore, several hundred feet higher than it was immediately 
on the lee side. A short distance farther down on the lee 
side, however, the ice closes up to its normal height at that 


48 THE ICE AGE IN NORTH AMERICA. 


point. In both instances, also, the lee side of these islands 
seemed to be the beginning of important subglacial streams 
of water—brooks running into them as into a funnel, and 
causing a backward movement of ice and moraine material, 
as where there is an eddy in water. In both these cases, 
however, the lee sides of these islands were those having 
greatest exposure to the sunshine. The surface of the ice 
immediately in front was depressed from one to two hun- 
dred feet below the general surface on the lee side. 

The ice in the eastern half of the amphitheatre is movy- 
ing much more slowly than that in the western half. Of 
this there are several indirect indications: First, the eastern 
surface is much smoother than the western. There is no 
difficulty in traversing the glacier for many miles to the east 
and northeast. Here and there the surface is interrupted by 
superficial streams of water occupying narrow, shallow chan- 
nels, running for a short distance and then plunging down 
into fissures, or, in technical language, mowlins, to swell the 
larger current, which may be heard rushing along in its im- 
petuous course far down beneath and out of sight. The 
ordinary light-colored bands in the ice parallel with its line 
of motion are everywhere conspicuous, and can be followed 
on the surface for long distances. When interrupted by cre- 
vasses they are seen to penetrate the ice for a depth of many 
feet, and sometimes to continue on the other side of a ere- 
vasse in a different line, as if having suffered a lateral fault. 
The color of the ice below the surface is an intense blue, and 
over the eastern portion this color characterized the most 
of the surface. Numerous holes in the ice, penetrating 
downward from an inch or two to several feet and filled with 
water, were encountered all over the eastern portion. Some- 
times there was a stone or a little dirt in the bottom of these, 
but frequently there was apparently nothing whatever in 
them but the purest of water. In the shallower inclosures 
on the surface, containing water and a little dirt, worms, 
about as large around as a small knitting-needle and an inch 
long, were abundant. 


—— ye 


A MONTH WITH THE MUIR GLACIER. 49 


The character and course of the moraines on the eastern 
half of the glacier also attest its slower motion. There are 
seven medial moraines east of the north-and-south line, four 
of which come in to the main stream from the mountains to ~ 
the southeast (see Fig. 24). Near the rim of the glacial am- 
phitheatre these are long distances, in some cases miles, 
apart; but, as they approach the mouth of the amphitheatre, 
they are crowded closer and closer together near its eastern 
edge, until in the throat itself they are indistinguishably 
mingled. The three more southern moraines unite some dis- 
tance above the mouth. One of these contains a large 
amount of pure marble. This moraine gradually approaches 
the others on either side until the distance between them 
disappears, and its marble unites with the other material to 
form one common medial moraine. The fifth moraine from 
the south is about 150 yards in width, five miles back from 
the mouth. It is then certainly as much as five and prob- 
ably eight miles from the mountains from which the débris 
forming it is derived. All these moraines contain many 
large blocks of stone, some of which stand above the general 
mass on pedestals of ice, with a tendency always to fall over 
in the direction of the sun. One such block was twenty feet 
square and about the same height, standing on a pedestal of 
ice three or four feet high. It is the combination of these 
moraines, after they have been crowded together near the 
mouth, which forms the deposit now going on at the north- 
east angle of the inlet just in front of the ice. Of this more 
will be said in connection with the question of the recedence 
of the glacier. Similar phenomena, though on a smaller 
scale, appear near the southwest angle of the amphitheatre. 

The dominant streams of ice in the glacier come from 
the north and the northwest. These unite in the lower por- 
tion to form a main current, about one mile in width, which 
is moving toward the head of the inlet with great relative 
rapidity. Were not the water in the inlet deep enough to 
float the surplus ice away, there is no knowing how much 
farther down the valley the glacier would extend. The 


50 THE ICE AGE IN NORTH AMERICA. 


streams of ice from the east and southwest have already 
spent the most of their force on reaching the head of the 
inlet; and, were it not for this central ice-stream, a natural 


equilibrium of forces would be established here independent — 


of the water, and no icebergs would be formed. The sur- 
face of this central current of motion is extremely rough, so 
that it is entirely out of the question to walk far out upon 
it. On approaching this portion of the glacier from the 
east the transverse crevasses diagonal to the line of motion 
increase in number and size until the whole surface is broken 
up into vast parallelograms, prisms, and towers of ice, sep- 
arated by yawning and impassable chasms scores and hun- 
dreds of feet in depth. Over this part of the ice the mo- 
raines are interrupted and drawn out into thinner lines, often 
appearing merely as patches of débris on separate masses of 
ice. This portion of the ice-current presents a lighter 
colored appearance than other portions, and the roughened 
lines.of motion can be followed, as far as the eye can reach, 


through distant openings in the mountains to the north and— 


the northwest. 

The comparative rapidity of the motion in this part of 
the ice is also manifest where it breaks off into the water at 
the head of the inlet. As already said, the perpendicular 
front of ice at the water’s edge is from 250 to 300 feet in 
height. From this front there is a constant succession of 
falls of ice into the water, accompanied by loud reports. 
Searcely ten minutes, either day or night, passed during the 
whole month without our being startled by such reports, and 
frequently they were like thunder-claps or the booming of 
cannon at the bombardment of a besieged city, and this, 
though our camp was two and a half miles below the ice- 
front. Sometimes this sound accompanied the actual fall of 
masses of ice from the front, while at other times it was 
merely from the formation of new crevasses or the enlarge- 
ment of old ones. Repeatedly I have seen vast columns of 
ice, extending up to the full height of the front, topple over 
and fall into the water. How far these columns extended 


A MONTH WITH THE MUIR GLACIER. ol 


below the water could not be told accurately, but I have 
seen bergs floating away which were certainly 500 feet in 
length. At other times masses would fall from near the 
summit breaking off part way down, and splashing the spray 
up to the very top of the ice, at least 250 feet. The total 
amount of ice thus falling off is enormous. Bergs several 
hundred feet long and nearly as broad, with a height of from 
twenty to sixty feet, were numerous and constantly floating 
out from the inlet. The steamer meets such bergs a hun- 
dred miles away. The smaller pieces of ice often so cover 
the water of the inlet two or three miles below the glacier 
that it is with great difficulty that a canoe can be pushed 
through them. One of the bergs measured, was sixty feet 
above water and about four hundred feet square. The por- 
tion above water was somewhat irregular, so that probably a 
symmetrical form thirty feet in height would have contained 
it. But even at this rate of calculation the total depth 
would be two hundred and forty feet. The cubical contents 
of the berg would then be almost 40,000,000 feet. Occa- 
sionally, when the tide and wind were favorable, the inlet 
would for a few hours be comparatively free from floating 
ice; at other times it would seem to be full. 

The movements of the glacier in its lower portions are 
probably facilitated by the subglacial streams issuing from 
the front. There are four of these of considerable size. 
Two emerge in the inlet itself, and come boiling up, one at 
each corner of the ice-front, making a perceptible current 
in the bay. There are also two emerging from under the 
ice where it passes the shoulders of the mountains forming 
the throat of the glacier. These spout up, like fountains, 
two or three feet, and make their way through a channel in 
the sand and gravel of the terminal moraine for about a 
mile, and enter the inlet 250 or 300 yards south of the ice- 
front. These streams are perhaps three feet deep and from 
twenty to forty feet wide, and the current is very strong, 
since they fall from 150 to 250 feet in their course of a mile. 
It is the action of the subglacial streams near the corners of 


52 THE 1CE AGH IN NORTH AMERICA. 


the inlet which accounts for the more rapid recession of the 
glacier-front there than at the middle point projecting into 
the water south of the line joining the east and west corners. 
It was also noticeable that the falls of ice were much more 
frequent near these corners, and the main motion of the ice 
as afterward measured was, not toward the middle point 
projecting into the inlet, but toward these corners where the 
subglacial streams emerged below the water. 

No small dittculty was encountered in securing direct 
measurements of the motion; and, as the results may be 
questioned, I will give the data somewhat fuily. As it 
was impossible to cross the main current of the glacier, we 
were compelled to take our measurement by triangulation. 
But even then it seemed at first necessary to plant flags as 
far out on the ice as it was safe to venture. This was done 
on the second day of our stay, and a base-line was established 
on the eastern shore, about a mile above the mouth, and the 
necessary angles were taken. But, on returning to repeat the 
observations three or four days afterward, it was found that 
the ice was melting from the surface so fast that the stakes 
had fallen, and there were no means at command to make 
them secure. Besides, they were not far enough out to be 
of much service. It appeared also that the base-line was 
on a lateral moraine, which was, very likely, itself in motion. 
But by this time it had become evident that the masses of 
ice uniting to compose the main stream of motion retained 
their features so perfectly from day to day that there was no 
difficulty in recognizing many of them much farther out 
than it was possible to plant stakes. Accordingly, another 
base-line was established on the east side opposite the pro- 
jecting angle of ice in the inlet. From this position eight 
recognizable points in different portions of the ice-field were 
triangulated—the angles being taken with a sextant. Some of 
the points were triangulated on five different times, at inter- 
vals from the 11th of August to the 2d of September. Others 
were chosen later and triangulated a less number of times. 

The base-line finally chosen (marked B on Fig. 24) was at 


x —- 


es SS rl 


eS 


_— >». =. 


a ee a 


a es ee ee 


y= = 


4 
* 
| 
, 


» 


a i, il 


A MONTH WITH THE MUIR GLACIER. 53 


the foot of the mountain exactly east by the compass from 
the projecting angle of ice in the inlet. The elevation of 
the base-line was 408 feet above tide—corresponding to that 
of the ice-front. The distance of this projecting point of 
ice (marked C on Fig. 24) from the base-line was 8,534 feet, 
and it remained very nearly stationary during the whole 
time—showing that the material breaking off from the ice- 


Sein? 
s, 


Drtet aote 


— 


beet 


(ite mas 9S! 


es 


=e 


i Mile ‘ 


Fie. 24.—Map of Muir Inlet, showing converging moraines, and form of front. Buried 
forest, A ; base of triangulation, B. 


54 THE ICH AGE IN NORTH AMERICA. 


front was equal to that pushed along by the forward .move- 
ment. Satisfactory observations were made upon eight other 
points numbered and located on Fig. 24. 

No. 1 was a pinnacle of ice 1,476 feet north by 30° east 
from C. The movement from August 14th to August 24th 
was 1,653 feet east by 15° south. After this date the pinna- 
cle was no longer visible, having disappeared along the wast- 
ing line of front between C and the subglacial stream at the 
northeast corner of the inlet. This was so near the front as 
to be left out of the ordinary calculations. 

No. 2 was a conspicious pinnacle of ice 2,416 feet north 
by 16° east of C. Observations were continued upon this 
from August 11th to September 2d. The total distance 
moved during that time was 1,417 feet, or about sixty-five 
feet per day. From August 14th to August 24th the move- 
ment was 715 feet, or about seventy-one feet per day. The 
difference is, however, perhaps due to the neglect to record 
the hours of the day when the observations were taken. As 
these observations were wholly independent of each other, 
their substantial concordance demonstrates that there was no 
serious error in the observations themselves. The direction 
of movement of this point of ice was very nearly the same 
as that of the preceding, namely, east 16° south. This also 
is toward the subglacial stream emerging from the northeast 
corner of the inlet. 

No. 3 was observed only from August 20th to August 
24th. It was situated 3,893 feet north by 62° east of C, and 
moved 105 feet in a westerly direction, about twenty-six feet 
per day. The westerly course of this movement probably 
arose from its being near where the easterly and northeast- 
erly currents joined the main movement. 

No. 4 was 5,115 feet north, 42° east of C, and moved 
from August 20th to August 24th 143 feet in a southeast- 
erly direction, or thirty-six feet per day. 

No. 5 was 5,580 feet north, 48° east of C, and moved 289 
feet from August 20th to August 24th in a direction east by 
39° south, or seventy-two feet per day. 


A MONTH WITH THE MUIR GLACIER. ay) 


No. 6 was 5,473 feet north, 70° east of C, and moved 232 
feet from August 11th to September 2d in a direction south 
66° east, or ten feet per day. 

No. 7 was 6.903 feet north, 59° east of C, and moved 89 
feet between August 14th and August 24th, in a direction 
south 3° east, about nine feet per day. 

No. 8 was 7,507 feet north, 62° east of C, and moved 265 
feet from August 14th to August 24th, in direction south 56° 
east. These last three points lay in one of the moraines on 
the east side of the line of greatest motion and parallel with 
it. These moraines are much interrupted in their course by 
gaps. 

It is observable that these points are all east of the center 
of the main line of most rapid motion, and are tending with 
varying velocity toward the northeast corner of the inlet, 
where the powerful subglacial stream emerges from below 
the water-level. Doubtless, on the other side of the center 
of motion, and at the same relative distance from the front, 
the ice would be found tending toward the northwest corner 
of the inlet, where a similar subglacial stream emerges. 

From these observations it would seem to follow that a 
stream of ice presenting a cross-section of about 5,000,000 
square feet (5,000 feet wide by about 1,000 feet deep) is 
entering the inlet at an average rate of forty feet per day 
(seventy feet in the center and ten feet near the margin of 
movement), making about 200,000,000 of cubic feet per day 
during the month of August. The preceding remarks upon 
the many indirect evidences of rapid motion render the cal- 
culation perfectly credible. What the rate may be at other 
times of the year there are at present no means of knowing. 

The indications that the glacier is receding, and that its 
volume is diminishing, are indubitable and numerous. The 
islands of southern Alaska are ordinarily covered with forests 
of cedar, hemlock, and fir, up to the level of 1,500 or 2,000 
feet above tide. But to this rule the shores and islands of 
the upper part of Glacier Bay are a striking exception. Near 
the mouth of the bay, forests continue to occur as in other 


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K'N-02 ONT OL0Ha 


A MONTH WITH THE MUIR GLACIER. a7 


parts, only on a diminished scale; but in the upper half of 
the bay all the shores and islands are perfectly bare of forests, 
and the rocks retain in the most exposed situations fresh 
grooves and striz of glacial origin. It would be impossible 
for rocks so exposed in such a climate to retain these for an 
indefinite length of time. Far up on the mountains, also, 
there are remnants of glacial débris in situations such that 
the material could not have resisted erosive agencies for any 
great length of time. The triangular-shaped terminal moraine 
on the eastern side, just below the ice-front, presents some 
interesting features bearing on the same point. This extends 
three miles below the glacier, and in its lower portions is 
thinly covered with vegetation. This covering becomes less 
and Jess abundant as the glacier is approached, until, over the 
last mile, scarcely any plants at all can be found. Apparently 
this is because there has not been time for vegetation to 
spread over the upper portion of the moraine since the ice 
withdrew, for on the mountains close by, where the exposure 
has been longer, there is a complete metting of grass, flower- 
ing plants, and shrubs. Again, in this triangular moraine- 
covered space there are five distinct transverse ridges, mark- 
ing as many stages in the recession of the ice-front (see Fig. 
24). These moraines of retrocession run parallel with the 
ice-front on that side, and at about equal distances from each 
other, each one rising from the water’s edge to the foot of the 
mountain, where they are 408 feet above tide. An inspec- 
tion of the upper moraine-ridge shows the manner of its for- 
mation. ‘This transverse ridge is half a mile below the ice- 
front, and is still underlaid in some portions with masses of 
ice ninety feet or more in thickness, which are melting away 
on their sides and allowing the débris covering them to slide 
down about their bases. Kettle-holes are in all stages of for- 
mation along this ridge. The subglacial stream emerging 
from the southeast corner of the glacier next the mountain 
rushes along just in the rear of this moraine-ridge, and in 
front of a similar deposit in process of formation on the very 
edge of the ice where the medial moraines spoken of termi- 


58 THE ICE AGE IN NORTH AMERICA. 


nate. Eventually this stream will break out in the rear of 
that deposit also, and leave another ridge similar to the one 


Fie. 26.—In the foreground on the right is a mass of ice, one half mile in front of the gla- 
cier, one hundred or more feet thick, covered with gravel, slowly sliding down to form 
the rim of a kettle-hole. The mountain back is 3,100 feet high. Near B, Fig. 22. 


now slowly settling down into position south of it. This first 
ridge south of the subglacial stream, with its ice still melting 
in exposed positions under its covering of gravel, can not be 
many years old. 

Still another sign of the recent date of this whole moraine 
appears at various places where water-courses, coming down 
from the mountain, are depositing superficial deltas of débris 
upon the edge of the glacial deposit. These deltas are very 
limited in extent, though the annual deposition is by no 
means insignificant. At the southern apex of the moraine, 
three miles below the ice-front, and but one hundred or two 
hundred yards from our camp, great quantities of débras came 
tearing down in repeated avalanches during a prolonged sea- 
son of rain. Twenty-five years would be more than ample 
for the formation of the cone of débris at the foot of this line 
of avalanches. Thus there can be no reasonable doubt that 


eS Se eC 


A MONTH WITH THE MUIR GLACIER. 99 


during the earlier part of this century the ice filled the inlet 
several miles farther down than now. And there can be 
scarcely less doubt that recently the glacier filled the inlet, 
2,500 feet above its present level near the front; for the 
elacial débris and striz are very marked and fresh on both 
mountains flanking the upper part of the inlet up to that 
height, and the evidences of an ice-movement in the direction 
of the axis of the bay are not wanting as high as 3,700 feet 
on the eastern mountain, where I found fresh striz running 
north by south, and directly past the summit, which rises 
1,000 or 1,500 feet still higher, just to the east. 

To this circumstantial evidence may be added what seems 
to be an irresistible inference from the notes of Vancouver's 
party in 1794. This party entered Cross Sound in small 
boats, and penetrated as far as the head of Lynn Canal and 
Juneau. 

The following is the record. Weshould premise, how- 
ever, that the point referred to as seven miles from Point 
Dundas is probably that at the southeastern corner of Gla- 
cier Bay, and the “spacious inlet lying in an east-southeast ” 
direction is probably the channel extending toward Chatham 
Strait. But certainly, no one looking from that point at the 
present time would speak, as this report does, of this inlet as 
seeming to be “entirely occupied by one compact sheet of 
ice as far back as the eye could distinguish.” Nor would 
the observer at the present time say that, to the north and 
east, the two large open bays formed by the shores of the 
continent seemed to be “‘ terminated by compact solid mount- 
ains of ice rising perpendicular from the water’s edge.” 
The ice is now full twenty-five miles away from that point, 
and the ice-front is not sufficiently prominent to make such 
an impression as this. It is hence more than probable that, 
at that time, the ice extended down nearly to the mouth of 


the bay. 


The morning of the 12th [July], though unpleasant, was 
rather more favorable to their pursuit, which was still greatly 


led 


‘ 


60 THE ICE AGE IN NORTH AMERICA. 


impeded by the ice. From the east point of this branch, 
which I have called Point Dundas, situated in latitude 58° 21’, 
longitude 224° 1’, the coast takes an irregular east-northeast 
direction about seven miles to a point whence this branch of 
the [Cross] Sound appeared to be very extensive in an east- 
southeast point of view, and was upward of three leagues across. 
The party proceeded from Point Dundas to this station, 
through a channel from two to three miles in width, between 
the continental shore and an island about seven miles long 
and three miles broad, lying in a northeast and southwest di- 
rection. This spacious inlet presented to our party an ardu- 
ous task, as the space between the shores on the northern and 
southern sides seemed to be entirely occupied by one compact 
sheet of ice as far as the eye could distinguish. ... To 
the north and east of this point the shores of the continent 
form two large open bays, which were terminated by compact 
solid mountains of ice, rising perpendicularly from the water’s 
edge, and bounded to the north by a continuation of the united 
lofty frozen mountains that extend eastward from Mount Fair- 
weather. In these bays also were great quantities of broken 
ice, which, having been put in motion by the springing up of 
a northerly wind, was drifted to the southward, and, forcing 
the boats from the northern shore, obliged them to take shel- 
ter round the northeast point of the above island. ‘This made 
Mr. Whidbey apprehensive that the still apparent connected 
body of ice, from side to side, would at length oblige him to 
abandon his researches by this route, unless he should find it 
possible to force a passage through this formidable obstruc- 
tion. 

In attempting this, the party succeeded far beyond their 
expectations, for they gained an open navigation, and by four 
in the afternoon arrived at a low and nearly round island 
about two leagues in circuit, lying from the former island 
north 83° east, distant three leagues. This island is moder- 
ately elevated, its shores pleasant and easy of access, and well 
stocked with timber, mostly of the pine tribe. It presented a 
much more inviting appearance than they had been accustomed 
to behold, and the weather being more favorable than for 
some time past, they continued along the continental shore, 


A MONTH WITH THE MUIR GLACIER. 61 


passing within some islets that lie about a league to the east- 
ward of the round island, until nine in the evening, when it 
became calm, and the party rested for the night at the entrance 
of a brook, ina bay on the northern or continental shore, 
which from the round island les south 82° east, distant ten 
miles. * 


If we understand this, the bay to the north is Glacier 
Bay, down which the ice must then have extended south of 
Willoughby Island and to within a few miles of Cross Sound. 
Otherwise no such description could have been given. The 
bay to the east is probably the extension of the sound toward 
the mouth of Lynn Canal, and very likely glaciers at that time 
came down toward the west from the White Mountains and 
produced the appearance described. From what has already 
been said of the evidence showing the present recession of 
the Muir Glacier, it is not at all incredible that glaciers 
nearly filled the whole bay a hundred years ago. 

All this is necessary to a comprehension of a most inter- 
esting problem presented by the buried forests near the south- 
west corner of the glacier (see A, Fig. 24). Below this corner, 
and extending for about a mile and a half, there is a gravel 
deposit, similar to that on the eastern side, except that it is 
not marked by transverse ridges, but is level-topped, rising 
gradually from about 100 feet at its southern termination to 
a little over 300 feet where it extends north and west of the 
ice-front (see Fig. 24). The subglacial stream entering the 
inlet just below the southwest corner of the ice emerges from 
the ice about a mile farther up, on the north side of the pro- 
jecting shoulder of the western mountain which forms that 
side of the gateway through which the glacier enters the in- 
let. This stream comes principally from the decaying western 
branch of the glacier before alluded to, and, after winding 
around the projecting shoulder of the mountain, which is 
315 feet above tide, has worn a channel through the gravel 


* ““ Voyage of Discovery around the World,” vol. v, pp. 420-423. 


62 THE ICE AGE IN NORTH AMERICA. 


deposit lying between the lower mile of the glacier and the 
mountain a short distance to the southwest. About half-way 
down, a small brook, coming from between this latter mount- 
ain and that whose shoulder forms the western part of the 
gateway just north of it, joins the main stream issuing from 
the glacier on this side. Where these streams unite, at A, 
they are now uncovering a forest of cedar-trees in perfect 
preservation, standing upright in the soil in which they 


Fic. 27—Buried Forest on the Muir Glacier, looking west. 


grew, with the Awmus still about their roots. An abundance 
of their cones, still preserving their shape, lies about their 
roots ; and the texture of the wood is still unimpaired. One 
of these upright trunks measured ten feet in cireumference 
about fifteen feet above the roots. Some of the smaller up- 
right trees have their branches and twigs still intact, pre- 
serving the normal conical appearance of a recently dead 
cedar-tree. 

These trees are in various stages of exposure. Some of 


ie 


} 


i 
4 
i 


d 
tig WR = 


A MONTH WITH THE MUIR GLACIER. 63 


them are uncovered to the roots ; some are washed wholly out 
of the soil; while others are still buried and standing upright, 
in horizontal layers of fine sand and gravel, some with tops 
projecting from a depth of twenty or thirty feet, others being 
doubtless entirely covered. The roots of these trees are in a 
compact, stiff clay stratum, blue in color, without grit, inter- 
sected by numerous minute rootlets, and which is, in places, 
twenty feet thick. There is also, occasionaily, in this sub- 


Fie. 28.—Shows stumps of trees on east side of the glacial torrent. Note the line of sep- 
aration between the enveloping sand and the soil in which the roots are imbedded. 
A stump appears on the right, split in two, but one half standing. The gravel corre- 
sponds in height with that on the west side. The glacier appears in the background 
on the right. (From photograph, looking north.) 


stratum of clay, a small fragment of wood, as well as some 
smooth pebbles from an inch to two feet in diameter. The 
surface of this substratum is at this point 85 feet above the 
inlet. The deposit of sand and gravel covering the forest 
rises 115 feet higher, and is level-topped at that height, but 
rising toward the north till it reaches the shoulder of the 
mountain at an elevation of 300 feet. The trees are essen- 
tially like those now growing on the Alaskan mountains. 
Many of them have been violently broken off from five to 


64. THE ICE AGE IN NORTH AMERICA. 


twenty feet above their roots. This has been done by some 
force that has battered them from the upper side at the point 
of fracture. Evidently cakes of ice brought down by the 
streams indicated in the map, when flowing at various high- 
er levels than now, have accomplished this result; for the 
trunks in the main stream were battered on the north side, 
while those in the gully worn by the lateral stream were bat- 
tered from the west side. 

From this description the explanation would seem to be 
evident. At some period, when the ice occupied only the 
upper part of the valley to the north of this point, forests: 
grew over all the space lying southwest of the present ice- 
front. As the ice advanced to near its present position, the 
streams carrying off the surplus water from the western half 
of the advancing glacier were suddenly turned into the pro- 
tected space occupied by this forest, where they deposited 
their loads of sand and gravel. A cause very likely com- 
bining to facilitate deposition in this spot has not yet been 
spoken of, but is evident from a glance at the maps. A trans- 
verse valley passes just below this point from Muir Inlet to 
the western inlet into which Glacier Bay divides. This 
transverse valley is at present occupied by a decaying glacier 
opening into both inlets, and sending a subglacial stream 
through a long, narrow series of moraines, into Muir Inlet 
about two miles to the south. Now, when a general advance 
of the ice was in progress, this transverse glacier probably 
pushed itself down into the inlet across the path of the ice 
moving from the north, and so formed an obstruction to the 
water running from the southwest corner of the main glacier, 
thus favoring the rapid deposition which so evidently took 
place. When this inclosed place was filled up, and the ad- 
vancing ice had risen above and surmounted the projecting 
shoulder of the mountain just to the north, that rocky barrier 
protected a portion of the forest from the force of the ice- 
movement, causing the ice to move some distance over the 
top of the superincumbent gravel before exerting its full 
downward force. Thus sealed up on the lee side of this pro- 


A MONTH WITH THE MUIR. GLACIER. 65 


tecting ridge of rock, there would seem to be no limit to the 
length of time the forest might be preserved. I see no rea- 
son why this forest may not have existed before the Glacial 
period itself. | 

The existence of other forests similarly preserved in that 
vicinity is amply witnessed to by many facts. One upon the 
island near the west shore, four miles south, is now exposed 
in a similarly protected position. J*urthermore, the moraine, 
already described on the east side of the inlet, contains much 
wood ground up into slivers and fragments. Indeed, our 
whole dependence during the month for fuel was upon such 
fragments lying exposed in the moraine. Occasional chunks 
of peat or compact masses of sphagnum formed a part of the 
débris of this moraine. These also occurred on some of the 


pric rT Gia oar cae eae alc Peal ag, 


Fig. 29—Muir Glacier from an elevation of 1,800 feet. 


medial moraines on the eastern side. I did not go up them 
far enough to learn directly their origin ; but, as no forests 


66 THE ICE AGE IN NORTH AMERICA. 


were visible anywhere in that direction, it is presumable that 
they had been recently excavated from preglacial forests simi- 
lar in situation to that now exposed on the west below the 
ice-front. 

The capacity of the ice to move, without disturbing them, 
over such gravel deposits as covered the forests, is seen also 
in the present condition of the southwestern corner of the 
glacier itself. As the ice-front has retreated along that 
shore, large masses of ice are still to be seen lapping over 
upon the gravel. These are portions of the glacier still sus- 
tained in place by the underlying gravel, while the water of 
the mlet has carried the ice from the perpendicular bank 
clear away. This phenomenon, and that of the general per- 
pendicular front presented by the ice at the water’s edge, 
accord with the well-known fact that the surface of the ice 
moves faster than the lower portions. Otherwise the ice- 


columns at the front would not fall over into the water as 


they do. 

The formation of kames, and of the knobs and kettle- 
holes characteristic both of kames and of terminal moraines, 
is illustrated in various places about the mouth of Muir Gla- 
cier, but especially near the southwest corner, just above the 
shoulder of the mountain where the last lateral branch comes 
in from the west. This branch is retreating, and has already 
begun to separate from the main glacier at its lower side, 
where the subglacial stream passing the buried forest etnerges. 
Here a vast amount of water-worn débris covers the ice, ex- 
tending up the glacier in the line of motion for a long dis- 
tance. It is evident from the situation that, when the ice- 
stream was a little fuller than now, and the subglacial stream 
emerged considerably farther down, a great mass of débras 
was spread out on the ice at an elevation considerably above 
the bottom. Now that the front is retreating, this subglacial 
stream occupies a long tunnel, twenty-five or thirty feet high, 
in a stratum of ice that is overlaid to a depth, in some places, 
of fifteen or twenty feet with water-worn glacial débris. In 
numerous places the roof of this tunnel has broken in, and 


—————————— Oe ~~ 


= = SS ? 


A MONTH WITH THE MUIR GLACIER. 67 


the tunnel itself is now deserted for some distance by the 
stream, so that the debris is caving down into the bed of the 
old tunnel as the edges of ice melt away, thus forming a 
tortuous ridge, with projecting knolls where the funnels into 
the tunnel are oldest and largest. At the same time, the ice 
on the sides at some distance from the tunnel, where the 
superficial débrzs was thinner, has melted down much below 
the level of that which was protected by the thicker deposit ; 
and so the débr’s is sliding down the sides as well as into the 
tunnel through the center. Thus three ridges approximateiy 
parallel are simultaneously forming—one in the middle of 
the tunnel and one on each side. When the ice has fully 
melted away, this débris will present all the complications of 
interlacing ridges, with numerous kettle-holes and knobs 
characterizing the kames; and these will be approximately 
parallel with the line of glacial motion. The same condition 
of things exists about the head of the subglacial stream on 
the east side, also near the junction of the first branch glacier 
on the east with the main stream, as also about the mouth of 
the independent glacier shown on the map lower down on the 
west side of the inlet (see Fig. 24). The formation of kettle- 
holes in the terminal ridges has already been referred to. 

Considerable earthy material is carried out from the front 
by the bergs. Pebbles and dirt were frequently seen frozen 
into them as they were floating away. Just how many of the 
bergs were formed from ice that originally rested on the bot- 
tom of the inlet I have no means of telling. That some were 
so formed seems exceedingly probable, if for no other reasons 
because of the great amount of débris that was sometimes 
seen frozen into them. It is by no means certain that the 
subglacial streams boiling up near the upper corners of the 
inlet were beneath the lowest stratum of ice. Some small 
streams were seen pouring out from the face of the ice half- 
way up from the water. It seems likely that a great amount 
of sediment is conveyed into cavities in the center of the 
glacier through the action of these subglacial streams; and 
so is ready for transportation when the masses break loose. 


6S THE ICE AGE IN NORTH AMERICA. 


My estimates concerning the amount of sediment carried 
out by subglacial streams are as follows: The amount of sedi- 
ment contained in each United States gallon (23i cubic inches) 
of water collected from the subglacial streams is, as deter- 
mined by the analysis of the late Professor H. OC. Foote, of 
Cleveland, 708-48 grains. Estimating the total area oceupied 
by the glacial amphitheatre to be 1,200 square miles, and the 
annual precipitation the same as that at Sitka (which is not 
far from ninety-six inches), the total amount of water which 
must in some form annually pass into the inlet from this area 
is 267,632,640,000 eubic feet. Of this amount I estimate 
that 77,088,000,000 cubic feet passes out as ice, or, reducing 
this to water, about 67,000,000,000 eubic feet of liquid water. 
(This part of the calculation is based on.the fact approximate- 
ly ascertained that a section of ice one mile wide and 1,000 
feet deep is moving into the inlet at a rate of 40 feet per 
day.) Subtracting the ice from the total amount, and esti- 
mating that evaporation would probably diminish the amount 
one eighth, the total amount of water which must issue in 
all the subglacial streams from this glacier is 175,000,000,000 
cubic feet. Estimating the specific gravity of the sediment 
(which is chiefly some compound of alumina and silica) at 
two and a half, we have, as the total amount of sediment 
transported thus, 33,274,804 cubic yards. This equals not far 
from one third of an inch per year eroded from the total © 
area (1,200 square miles) occupied by the glacier. This 
would furnish one inch of sediment per year to be spread by 
this single glacier over the bottom of Glacier Bay. This 
confirms the statements concerning the recent recession of 
the glacier from the lower portion of the bay, since otherwise 
it would now be full of sediment. 

Besides the Muir Glacier several others of large size, 
such as the Grand Pacific and Hugh Miller Glaciers, descend 
from the flanks of Mts. Crillon and Fairweather into Reid 
Inlet, which projects several miles to the northwest from 
Glacier Bay. These do not differ materially in appearance 
and behavior from the Muir Glacier. 


A MONTH WITH THE MUIR GLACIER. 69 


I append the record of the thermometer from August 20th 
to August 31st, giving the mean of three readings each day 
taken at 84.m,2p.m,and8p.m. The temperature of the 
water in the upper part of the inlet was uniformly 40° Fahr. 


August 20, 49°4° Fabr. | August 24, 49°8° Fahr. | August 28, 50°5° Fahr. 
August 21, 48°9° Fahr. | August 25, 52°7° Fahr. | August 29, 45° Fahr. 

August 22, 46-1° Fahr. | August 26, 51-9° Fahr. | August 30, 54-8° Fahr. 
August 23, 44°6° Fahr. | August 27, 46-1° Fahr. | August 31, 50°5° Fabr. 


The following is the list of plants, as identified by Pro- 
fessor Asa Gray, found in bloom about Muir Inlet during the 
month of August. Where the altitude is not given, they were 
found near the tide: 


Arabis ambigua, Brong..........-..-.--- August 26, 1,600 A. T. 
Arxenaria peploides, L......-..22..22. .. August 28. 

pienrelas alpings, L.........2552.0. 20-5 August 7. 

Hedysarnm boreale, Nutt..............-. August 28. 
Sanguisorba Canadensis. ........... .... August 6. 

Lutkea sibbaldioides, Brong.............. August 27. 

Saxifraga Lyalli, Engl. .......... _...... August 26. 1,600 A. T. 
Saxifraga stellaris, L........ ethan ain. August 27, 3,000 A. T. 
Parnassia fimbriata, Smal]............... August 27, 3,000 A. T. 
BEM MMNOREATS, De. se te oe August 6. 

Epilobium latifolium, L.................- August 6, 1,600 A. T. 
Epilobium origanifolium Lam. (?)......... August 28. | 
Solidago multiradiata, Ait... .......-.... Augnst 27. 

Erigeron salsuginosus. Gray, arctic form.. August 27, 3,000 A. T. 
Antennaria margaritacea, arctic form... .. August 27. 

Achillea millefolium, L., arctic variety.... August 27. 

arms obtustiolin, Les.....00..-.-.-5 -- August 27, 1,200 A. T. 
Campanula rotundifolia, L., var. Alaskana. August 23. 

Gentiana platypetala (7)..... siete pean eat August 27. 

Gentiana Menviesi (7)... .......-.....-.- August 27. 

Mioreras ingrisiin: o.oo sb. 2 ele August 7. 

Castilleja parviflora, Brong.............- August 28. 

OTS ee a) a eo a Augnst 6. 

Habenaria hyperborea, R. Br............ August 27, 2,650 A. T. 
Luzula parviflora, Meyer. 

Poa alpina, variety vivipara.............- August 26, 1,500 A. T. 
RUMEN OS elle tite Siu wishin e o 4 o = = August 26, 1,600 A. T. 


So Sy Se Ee ee August 26, 1,500 A. T. 


70 THE {CH AGE IN NORTH AMERICA. 


Phleum: alpinum Wis. ete enna. 8 a August 26, 1,600 A. 'I. 
Helyaus* ca ols. cide ocho nis | eect 3 August 6. 
Herdeumi, ssp: /()e sc steers esteieie es O06: 07s August 6. 


eel 


Fie. 30.—Blocks of stone supported on ice-pillars, showing how they fall toward the sun. 
See above, page 49. United States Geological Survey (Russell). 


A MONTH WITH THE MUIR GLACIER. 71 


SUPPLEMENT TO CHAPTER III. 


For various reasons it is best to let this chapter stand as 
it was originally written. But it is necessary to append a 
summary of the results of subsequent observations by others, 
especially as they have a most important bearing on several 
questions of glacial theory. During the summers of 1890 
and 1892 Professor Harry Fielding Reid with a corps of 
competent assistants carefully surveyed the region and made 
extensive additions to our knowledge, not only of this glacier, 
but of glacial movements in general. 

The main facts, as determined by Professor Reid, do not, 
however, differ materially from ours. Our estimate of twelve 
hundred square miles for the area of the Muir Glacier would, by 
his calculations, be brought down to a thousand square miles. 
He failed, however, to detect any motion in the glacier greater 
than about ten feet per day. But it should be noted that he 
did not measure the central, and consequently most rapidly 
moving portion of the ice, but limited himself to calculating 
the motion of those portions of the ice which he could traverse, 
and upon which he could plant flags of observation. Thus, not- 
withstanding his utmost efforts, in going out from both direc- 
tions, about a quarter of a mile in width, as he informs me, re- 
mained untraversed, and his attempts to take angles, after the 
method pursued by us, upon the masses of ice themselves, failed 
of success. This was probably due to the fact that his base- 
line (near B in our map on page 53) was eight hundred feet 
higher upon the mountain than ours, so that he did not have 
the advantage which we had of seeing the domes and pinnacles 
of the central and higher portion of the ice projected upon the 
sky and the dark background of the mountains beyond. Hence 
it does not appear that there is any occasion to question the ap- 
proximate correctness of our figures as given on page 64. If, how- 
ever, I were to revise the estimates of the average rate of move- 
ment in the mass of ice, I should not place it quite so high as I 
have done on page 585, especially since in that calculation no 
allowance was made for the decrease of velocity toward the 
bottom. Taking this into account, together with the com- 


72 THE ICE AGE IN NORTH AMERICA. 


parative narrowness of the area of most rapid motion, the 
average movement of the mass is probably not over twenty 
feet per day, and this amount would perhaps account for 
the number of bergs floating away with the tide, especially — 
since now we must add to them the amount supplied by the 
recession of the front of the ice. 

With reference to the evidence of the recent recession of 
the glacier Professor Reid agrees entirely with me. By com- 
parison of his photographs with mine he found that in ‘‘the 
four years from 1886 to 1890 the western end of the ice front 
has receded. 1,200 yards and the eastern end 750 yards. The 
center also has receded about 1,000 yards, so that the average 
recession of the ice front is a little over 1,000 yards in the 
four years, or, say a mile in seven years . . . . It does not 
seem at all incredible that the ice from the various glaciers of 
Glacier Bay may have united to fill a large part of the bay 
100 years ago.” 

But it is no longer necessary to depend on this evidence 
alone. In 1906 Messrs. F. E. and C. W. Wright made an 
official investigation of the region with the following startling 
results. On comparing their map with that of Professor Reid 
made in 1892 they write that: 


Beginning with Muir Glacier and its tributaries the ice 
front has receded a maximum distance of 33,000 feet; Dirt 
Glacier is no longer tidal; White and Adams Glaciers are 
supplying very little ice to the general ice field; Morse Glacier 
terminus is about one mile from tide water . . . . Girdled 
Glacier and Berg Lake have not changed materially in aspect. 
The length of the total ice front of Muir Glacier is now over 
40,000 feet instead of 9,000 feet in 1892. The present ice 
front passes at its northern extremity at about the position 
of your 1,000 foot contour on the ice of 1892. This remarkable 
decrease in elevation is undoubtedly due not only to melting 
down but also to breaking down of the exposed ice masses. 
The ascent of the ice mass at this point is decidedly steep and 
the ice fairly cascades into the water. The present height of 
the ice fronts of all the tide water glaciers is about the same 


A MONTH WITH THE MUIR GLACIER. 73 


as noted by you in 1892 (150-250 feet), and is a noteworthy 
fact in connection with these glaciers. Muir Inlet is at present 
choked by the ice pack which promises to remain. congested 
so long as its source of supply is so active. A considerable 
portion of the present front of Muir Glacier is in very shallow 
water and in a few years should decrease in size very materially 
unless new avenues and inlets for tidal currents are exposed 
by the receding ice. Dying Glacier is still creeping back and 
wasting away. 

Carroll Glacier has not changed much in aspect during the 
last fourteen years; its terminal cliff has receded about 2,000 
feet and at present, apparently, is continuing to do so. It 
is discharging icebergs very slowly and Queen Inlet is nearly | 
free of ice. 

Rendu Glacier has also changed but little, and its front is 
about 2,000 feet back of its position in 1892. This inlet also 
is not impeded by any amount of ice. The small glacier cas- 
cading from the west near its terminus appears to have changed 
still less. 

In Reid Inlet the changes have been very great and things 
are still moving at arapid rate there. The inlet was congested 
with the ice pack last summer (1906) and on the south side 
near the large island the ice jam was completely frozen over 
and moved as one mass back and forth with the tides. 

Grand Pacific Glacier has receded and left the large granite 
island surrounded by water. It has receded nearly 20,000 
feet; but judging from the amount of ice it is now discharging 
and the shape of its valley it will not recede so rapidly in the 
next few years, other conditions remaining the same. 

Johns Hopkins Glacier has receded about 11,000 feet and is 
still sending off icebergs at arapid rate. The unnamed glacier 
directly east has become detached from it and is much like 
Reid Glacier in character and appearance. 

Reid Glacier has receded perhaps 5,000 feet and still 
preserves its original aspect as indicated on yourmap . 

Hugh Miller Glacier no longer reaches tide water in Heid 
Inlet and at low tide is nearly a mile back from it. The tide 
flats are long and with only a slight grade. In Hugh Miller 


74 THE ICE AGE IN NORTH AMERICA. 


Inlet this glacier was exposed to tide water only in the south- 
western bay, where its front is intercepted in its central part 
by a large promontory of light colored granite. Eight thou- 
sand feet is approximately its recession since 1892. Charpen- 
tier Glacier also receded about 9,000 feet and promises to con- 
tinue its recession rapidly, especially along its southern front, 
as its valley is opening out and allowing a greater exposure of 
ice front to the action of tide water. 

The small stagnant glacier east of Charpentier is simply 
melting away and will probably disappear in ten or twenty 
years. 

Favorite Glacier is still receding. Wood Glacier is no 
longer tidal and only a small part of Geikie Glacier ice front 
is exposed to salt water. Geikie Glacier has receded about 
5,000 feet during the past fourteen years. 

On the whole, recession has been the rule for the glaciers 
of Glacier Bay. Those glaciers have receded most whose fronts 
have, on recession, increased appreciably in length. In the 
past fourteen years the combined ice front of all the glaciers 
exposed to the tide water has increased from 17,000 feet to 
over 40,000 feet and the amount of recession has in that time 
alone equalled that of the previous twenty years. 

To the west of Glacier Bay, Brady Glacier in Taylor Bay 
has receded considerably. In Lituya Bay, the glacier at 
the northwestern end of the bay has advanced about one-half 
mile since 1894; the central and southeastern glaciers have 
apparently remained unchanged although the latter may have 
advanced slightly.* 


*H.F. Reid: ‘Variation of Glaciers,’’ xii, ‘‘Journal of Geology,”’ 
Xvi, pp. 52, 53. 


4 


=) 


Puats V—Muir Glacier in 1909. 


CHAPTER IV. 
‘THE GLACIERS OF GREENLAND. 


THE continental proportions of Greenland, and the ex- 
tent to which its area is covered by glacial ice, make it by 
far the most important accessible field for glacial observa- 
tions. The total area of Greenland can not be less than 500,- 
060 square miles—equal in extent to the portion of the 
United States east of the Mississippi and north of the Ohio. 
It is now pretty evident that the whole of this area, except 
a narrow border about the southern end, is covered by one 
continuous sheet of moving ice, pressing outward on every 
side toward the open water of the surrounding seas. 

For a long time it was the belief of many that a large 
region in the interior of Greenland was free from ice, and 
was perhaps inhabited. It was in part to solve this problem 
that Baron Nordenskidld set out upon his expedition of 
1883. Ascending the ice-sheet from Disco Bay, in latitude 
69°, he proceeded eastward for eighteen days across a con- 
tinuous ice-field. Rivers were flowing in channels upon the 
surface like those cut on land in horizontal strata of shale or 
sandstone, only that the pure deep blue of the ice-walls were, 
by comparison, infinitely more beautiful. These rivers were 
not, however, perfectly continuous. After flowing for a dis- 
tance in channels on the surface, they, one and all, plunged 
with deafening roar into some yawning crevasse, to find their 
way to the sea through subglacial channels. Numerous 
lakes with shores of ice were also encountered. 

“On bending down the ear to the ice,” says this explorer, 
“we could hear on every side a peculiar subterranean hum, 


Length of the [ce-Sheet, 1500 milek, 
maximum width, 700 miles; area,about 574,000 
eguare miles; altitude pf its central fragt, 
6,000 to 10,000 feet ahove the sea. 


C8 PEARY, 1886 


Godhavit\-4 Gtobshavn 
Disco es: 
Egedesmin® Aa |, ave nsSiOL A 183s 


ooo” 
ad 


&. Strim Fa.& SS. a . ? 
a Drona His Pcape aa 
ukkertoppen®, A HH | ‘Pinilik Fiord 


cP) 


Paton Ge a “Ne NATAKS 


* OMe sews se, 


— 
= 
= 


*, 


30 —T00 200 300 


Pr “Scale of Miles. 


40 30 


Fre. 31—Map of Greenland showing narrow margin free from ice. 


THE GLACIERS OF GREENLAND. 77 


proceeding from rivers flowing within the ice; and occasion- 
ally a loud single report like that of a cannon gave notice of 
the formation of a new glacier-cleft. . . . In the afternoon 
- we saw at some distance from us a well-defined pillar of mist 
which, when we approached it, appeared to rise from a bot- 
tomless abyss, into which a mighty glacier-river fell. The 
vast roaring water-mass had bored for itself a vertical hole, 
probably down to the rock, certainly more than 2,000 feet 
beneath, on which the glacier rested.” * 

At the end of the eighteen days, Nordenskidld found 
himself about 150 miles from his starting-point, and about 
5,000 feet above the sea. Here the party rested, and sent 
two Eskimos forward on skidor—a kind of long wooden 
skate, with which they could move rapidly over the ice, not- 
withstanding the numerous small circular holes which every- 
where pitted the surface. These Eskimos were gone fifty- 
seven hours, having slept only four hours of the period. It 
is estimated that they made about 75 miles, and attained an 
altitude of 6,000 feet. The ice is reported as rising in distinct 
terraces, and as seemingly boundless beyond. If this is the 
ease 225 miles from Disco Bay, there would seem little hope 
of finding in Greenland an interior freed from ice. So we 
may pretty confidently speak of that continental body of 
land as still enveloped in an ice-sheet. Up to about latitude 
75°, however, the continent is fringed by a border of islands, 
over which there is no continnous covering of ice. In 
south Greenland the continuous ice-sheet is reached about 
thirty miles back from the shore. , 

In 1886 Dr. Rink wrote: 


We are now able to demonstrate that a movement of ice 
from the central regions of Greenland to the coast continually 
goes on, and must be supposed to act upon the ground over 
which it is pushed, so as to detach and transport fragments of 
it for such a distance. . . . The plainest idea of the ice-forma- 
tion here in question is given by comparing it with an inunda- 


* “Geological Magazine,” vol. ix, pp. 393, 399. 


78 THE ICE AGE IN NORTH AMERICA. 


tion. . . . Only the marginal part shows irregularity ; toward 
the interior the surface grows more and more level, and passes 
into a plain very slightly rising in the same direction. It has 
been proved that, ascending its extreme verge, where it has 
spread like a lava-stream over the lower ground in front of it, 
the irregularities are chiefly met with up to a height of 2,000 
feet, but the distance from the margin in which the height is 
reached varies much. While under 683° north latitude, it took 
twenty-four miles before this elevation was attained ; in 623° 
the same height was arrived at in half the distance. . . . 

A general movement of the whole mass from the central re- 
gions toward the sea is still continued, but it concentrates its 
force to comparatively few points in the most extraordinary 
degree. These points are represented by the ice-fiords, through 
which the annual surplus ice is carried off in the shape of bergs. 
. . - In Danish Greenland are found five of the first, four of 
the second, and eight of the third (or least productive) class, 
besides a number of inlets which only receive insignificant 
fragments. Direct measurements of the velocity have now 
been applied on three first-rate and one second-rate fiords, all 
situated between 69° and 71° north latitude. 'The measure- 
ments have been repeated during the coldest and the warmest 


season, and connected with surveying and other investigations © 


of the inlets and their environs. It is now proved that the 
glacier branches which produce the bergs proceed incessantly 
at a rate of thirty to fifty feet per diem ; this movement being 
not at all influenced by the seasons. .. . 

In the ice-fiord of Jakobshavn, which spreads its enormous 


bergs over Disco Bay, and probably far into the Atlantic, the — 


productive part of the glacier is 4,500 metres (about 24 miles) 
broad. The movement along its middle line, which is quicker 
than on the sides nearer the shores, can be rated at fifty feet 
per diem. The bulk of ice here annually forced into the sea 
would, if taken on the shore, make a mountain two miles long, 
two miles broad, and 1,000 feet high. The ice-fiord of Tor- 
sukatak receives four or five branches of the glacier ; the most 
productive of them is about 9,000 metres (five miles) broad, 
and moves between sixteen and thirty-two feet perdiem. The 
large Karajak Glacier, about 7,000 metres (four miles) broad, : 


a ee. ee — 


THE GLACIERS OF GREENLAND. 79 


proceeds at a rate of from twenty-two to thirty-eight feet 
per diem. Finally, a glacier branch dipping into the fiord of 
Jtivdliarsuk, 5,800 metres (three miles) broad, moved between 
twenty-four and forty-six feet per diem.* 


Describing the “Isblink,” in latitude 623° north, Rink 
says : 


The whole surveyed area of the inland ice in this place is 
calculated at 450 square miles, and forms, by means of the 
tongued shape of its foremost part, in some measure a separate 
district, in which the principal changes of the whole margin, 
excepting the ice-fiords, are represented. Toward the interior 
it is bordered by a row of nunataks,t distant about forty miles 
from the seaward edge which our travelers had ascended as 
their starting-point. Here the origin of the ice over which 
they had passed was at once plainly visible; namely, that it 
could not have been formed on the spot, but was brought 
thither from the interior of the continent. The nunataks 
had been an obstacle to this movement ; on the east side, fac- 
ing the interior, the ice was broken and piled up several hun- 
dred feet against the rock, like breakers of an ocean, while to 
the south and north, and between the nunataks, it poured 
down like frozen waterfalls to be embodied in and leveled with 
the crust over which our explorers had traveled. .. . 

The recent explorations, as already mentioned, have proved 
that what now we designate as coast-land free from ice was for- 
merly covered with ice like the interior. This ancient ice-cov- 
ering reached, in the immediate vicinity of the present inland 
ice, a height of 3,000 to 4,000 feet, and, farther seaward, 2,000 
to 3,000 feet above the sea. All the usual traces of ancient 
ice-action, the erratic blocks and the ground rocks, are the 
same here as in northern Europe. 


* See “Transactions of the Edinburgh Geological Society” for February 18, 
1886, vol. v, part ii, pp. 286-293. 

+ Nunataks are simply mountain-tops projecting above the surface of the 
ice-fields, such as were described in the account of the Muir Glacier in Alaska. 
Nordenskidld was the first to describe them in Greenland, and gave them this 
name. 


80 THE ICE AGH IN NORTH AMERICA. 


Rink supposes the opening of new channels for the outlet 
of the ice through the fiords may have so relieved the interior 
as to account for this recedence of the ice.* 

Among the most important observations upon the rate of 
movement in the glaciers in Greenland are those made by 
the Norwegian geologist Helland, in the summer of 1875. 
During that season he nade a series of measurements on the 
glacier that enters the great Jakobshavn Fiord in the north- 
ern part of Disco Bay, about latitude 70°. The width of 
this glacier near its mouth he found to be about two miles 
and a half. The view from the peaks in the vicinity toward 
the east extended to a continuous ice-field on the distant 
horizon. The rate of motion reported by Helland was so 
great, that scientific men hesitated for some time to credit it. 
According to his measurements, the Jakobshavn Glacier, in 
the central portion of its current, was moving more than 
sixty feet per day, as compared with the three feet per day 
reported for Alpine glaciers. But the subsequent measure- 
ments of Steenstrup, given above, and those of my own upon 
the Muir Glacier in Alaska (made in 1886), amply sustain 
the conclusions of Helland. 

It is proper to observe here, again, that the movement of 
glacial ice is affected much less by the slope of its bottom 
than by the size of the stream itself. The friction of the 
ice upon the bottom and sides of its channel is so great, that, 
where the stream is both shallow and narrow, the motion 
must be almost completely retarded. On doubling the size 


* The list of explorers given by Rink is worthy of being honored, and is as 
follows: “Geologist K. J. V. Steenstrup (eight summers and two winters) ; 
Lieutenant G. Holm, of the Royal Navy (five summers and one winter); Lieu- 
tenant R. Hammer, of the Royal Navy (three summers and one winter); Lieuten- 
ant A. D. Jensen, of the Royal Navy (three summers); geologist Sylow (two 
summers); painter Groth (two summers); supernumerary officer Larsen (one 
summer) ; Lieutenant Garde, of the Royal Navy (two summers and one winter) ; 
geologist Knutsen, Norwegian (two summers and one winter); geologist Peter- 
sen (one summer); botanist Eberlin (two summers and one winter); painter 
Riis Carstersen (one summer). Steenstrup and Hammer did most.on the 
fiords.” 


THE GLACIERS OF GREENLAND. Sl 


of a semi-fluid stream, the relative amount of friction be- 
comes very much less, so that it will move more than twice 


Fig. 32.-_Map of Frederikshaab Glacier, between 62° and 63°, showing course of Lieuten- 
ant Jensen in 1878 (forty-seven and a half miles). The black part, ice ; white, 
land ; shaded, water ; J. N., Jensen’s nunataks ; D. N.. Dolager’s nunataks ; white 
lines on the black, crevasses ; arrows, glacier-flow. Five species of plants were found 
on the nunataks which still survive on the White Mountains (N. H.). Dana. 


as fast as before. This property of a semi-fluid is made suf- 
ficiently evident from a homely illustration. Molasses in 
eold weather will scarcely run at all through a gimlet-hole, 
while it will run with considerable freedom through an 
auger-hole. Now, the glaciers of the Alps, which were the 
subjects of Professor Tyndall’s measurements, were, in com- 
parison to those in Greenland and Alaska, about in the pro- 
portion of a small gimlet-hole to a large auger-hole, and the 
faster motion is really not surprising. 


82 THE ICE AGE IN NORTH AMERICA. 


Helland’s observations as to the amount of ice floating 
away from the glacier in bergs amply confirm the direct cal- 
culation. The depth of the Jakobshavn Fiord is about 
1,200 feet, so that icebergs cf vast size can float off upon its 
waters. The daily discharge of ice through this fiord was 
estimated by him to be 432,000,000 cubic feet—about three 
times the calculation I have made for the Muir Glacier in 
Alaska. In addition to the formation of large icebergs, the 
discharge of ice from such a glacier as that at Jakobshavn is 
doubtless accompanied by a continual cannonade of countless 
smaller fragments, keeping the heavens full of thundering 
sounds and the waters full of commotion. From this it fol- 
lows that the movement of the great glaciers must be rapid, 
to account for the enormous numbers of first-class icebergs 
which are encountered in the vicinity, and for the numerous 
and immense ice-floes composed of smaller fragments. 

While the attention is fixed on the movement of the gla- 
ciers, we should not fail to note the uniform presence of 
subglacial streams of water emerging from their fronts. 
Such streams are usually in proportion to the size of the gla- 
cier, and, as already remarked, are most powerful agencies in 
the transportation of earthy material. The amount of sedi- 
ment thus brought out by a single subglacial stream on the 
west coast of Greenland is estimated to be from 15,000 to 
20,000 tons daily ; and the amount of water discharged in 
the stream is far larger than that which passes off as ice. 

The existence of such subglacial streams reveals much 
concerning the condition of the glaciers themselves. The 
question at once arises, Whence does the water come? The 
answer is found in the facts already mentioned by Norden- 
skidld concerning the superficial streams of water uniformly 
encountered on penetrating the glaciated interior of Green- 
land. Doubtless, also, much water arises from the melting 
of the lower strata of ice through the heat produced by the 
friction attendant upon the motion. 

Mr. Whymper’s descriptions add vividness to our knowl- 
edge of the Greenland Glacier in the latitude of Disco :. 


THE GLACIERS OF GREENLAND. 83 


In 3 paper communicated to the “Alpine Journal” in 
1870, I wrote in relation to this part of Greenland and the 
country to its north and south: 

The great ice-covered interior plateau of Greenland can 
be seen a long way off if the weather is clear. Its summit is 


ET TT ea ea TE 


Fic. 33.—Ikamiut Fjord, Greenland, showing hanging glaciers. Glaciers at head of 
the Fjord come to water’s edge. 


almost a dead level from north to south. But when one 
comes nearer to the coast it is concealed by the hills which 
are on its outskirts. The whole of the (outer) land on the 
(west) Greenland coast is mountainous, and although the hills 
scarcely ever, if ever, exceed a height of 8000 or 9000 feet, 
they effectually conceal the inner or glacier-covered land: 
This latter is at a distance from the coast varying from ten 
to sixty or more miles, and, when it is reached, there is 
an end to land—all is ice, as far as the eye can see. Great 
as the mass of ice is which still envelops Greenland, there 
were times when the land was even more completely cov- 
ered up by it; indeed, there is good reason to suppose that 
there was a time when every atom of the country was covered, 
and that life was hardly possible for man. . . . With the 
exception of places where the rocks are easy of disintegra- 


84 THE ICE AGE IN NORTH AMERICA. 


tion, and the traces of glacier action have been to a great ex- 


tent destroyed, the whole country bears the marks of the grind- 
ing and polishing of ice; and, judging by the flatness of the 
curves of the roches moutonnées, and by the perfection of the 
polish which still remains upon the rocks, after they have sus- 
tained many centuries of extreme variations of temperature, 
the Glacial period during which such effects were produced 
must have vastly exceeded in duration, or severity, the Glacial 
period of Europe ; and the existing great interior ice-plateau 
of Greenland, enormous as it is, must be considered as but the 
remnant of a mass which was incalculably greater, and to 
which there is no parallel at the present time, excepting within 
the Antarctic Circle. 

And later on, in my book, ‘‘ Scrambles among the Alps,” 
1871, pages 246, 247: 


The interior of Greenland appears to be absolutely covered | 


by a glacier between 68° 30’-70° north latitude. . . . On two 
occasions, in 1867, I saw, at a glance, at least 6,000 square 


miles of it from the summits of small mountains on its out-— 


skirts. Not a single peak or ridge was to be seen rising above, 
nor a single rock reposing upon the ice. The country was 


completely covered up by glaciers ; all was ice, as far as the eye - 


could see. . . . This vast ice-plateau, although smaller than it 
was in former times, is still so extensive that the whole of the 
glaciers of the Alps might be merged into it withnome its bulk 
being perceptibly increased. 

In 1872 I again traveled in northwestern Greenland, and 
by ascending various lofty mountains saw more of the “ inland 
ice” ; and in the ‘‘Alpine Journal” for 1873, page 220, I 
wrote : 

From all the principal summits you perceive the vast gla- 


cier-clad interior of the country, stretching from north to- 


south in an unbroken line, with a crest as straight as a sea- 
horizon. There are no marks upon it which enable one to cal- 
culate the altitude to which it rises, or the distance to which 
it extends. But having now seen it from several elevated and 
widely separated positions, as I find that its summit-line always 
appears lofty, even from the highest mountains which I have 
ascended, my impression is that its height is generally not less 


THE GLACIERS OF GREENLAND. 85 


than 8,000 feet, and in some places, perhaps, surpasses 10,000 
J?) eee 

On ascending hills on the outskirts I again had extensive 
views to the east, finding the land, as before, absoluteiy cov- 
ered by glaciers. From the nearest parts to the farthest dis- 
tance that could be seen, the whole of the ice was broken up 
into séracs. It was almost everywhere riven and fissured in a 
most extreme manner, and it was obviously totally impracti- 
cable for sledges. . .. 

From the repeated views of the interior which had been 
seen from the coast mountains, it was clear that all this part 
of Greenland, except the fringe of land on the Davis Strait 
side, was absolutely covered by snow and ice, and that the in- 
terior was not broken up in those latitudes as I had conjectured 
it might be... . 

This vast glacier is the largest continuous mass of ice at 
present known. All the glaciers of the Alps combined are as 
nothing to it, and the greatest of those in the Himalayas are 
mere dwarfs in comparison. At Jakobshavn the bergs floating 
away were often from 700 to 800 feet thick, and this is the only 
information at present possessed of its depth. The angle at 
which its surface rises toward the east is very slight, being 
seldom so much as 8°, and generally much less; while in some 
places there are considerable depressions, and lakes are formed 
In consequence. .. . | 

Mount Kelertingouit was 6,800 feet high, and there was a 
grand and most interesting view from its summit in all direc- 
tions. Southward it commanded the whole breadth of the 
Noursoak Peninsula, and extended over the Waigat Strait to 
the lofty island of Disco; westward it embraced the western 
part of the Noursoak Peninsula, with Davis Strait beyond ; 
northward it passed right over the Umenak Fiord (some thirty 
miles wide) to the Black Hook Peninsula; to the northeast it 
was occupied by the fiord, with its many imposing islands and 
islets, surrounded by innumerable icebergs streaming away 
from the inland ice ; and in the east, extending from north- 
east to southeast, over well-nigh 90° of the horizon, there was 
the inland ice itself—presenting the characteristic features 
which have been mentioned in the earlier papers. The south- 


86 THE ICE AGE IN NORTH AMERICA. 


ern part of the view of the inland ice, as seen from Kelertin- 
gouit, overlapped the northern part of it as seen on former 
occasions, while northward it extended to at least 71° 15’ north 
latitude, so I had now viewed the section of the interior be- 
tween 68° 30’ and 71° 15’, equal to 190 English miles, and had 
everywhere found a straight, unbroken crest of snow-covered 
ice, concealing the land so absolutely that eo a single crag 
appeared above its surface. 

The height of this straight, unbroken crest of snow was 
now the object of attention—the principal object for which 
the ascent was made. On bringing the theodolite to-bear upon 
it, | found that it appeared to be slightly depressed below my 
station ; but, as it was distant more than one hundred miles, 
it was only lower im appearance and not in reality. On the 
assumption that it was no more than one hundred miles dis- 
tant, after making allowance for the refraction and curvature 
of the earth, its height was found to be considerably in excess 
of ten thousand feet.* 


Northward from this point explorations have been carried 
on incessantly since the middle of the last century begin- 
ning with the expeditions of Drs. Kane and Hayes between 
the years 1855 and 1862. These remarkable men were 
associated from 1853 to 1855, in the second Grinnell Expe- 
dition in search of Sir John Franklin, which succeeded in 
exploring the coast on the east side of Smith Sound from 
Cape Alexander, in latitude 78°, to Washington Land, in 
latitude 80°; while in 1861 and 1862 Dr. Hayes conducted 
an independent expedition to Lady Franklin Bay, in lati- 
tude 82°, and resurveyed portions of his former field. 

In the neighborhood of Cape Dudley Digges, about lati- 
tude 76°, Dr. Kane’s party encountered a glacier which he 
describes as follows: 


This glacier was about seven miles across at its ‘de- 
bouche” ; it sloped gradually upward for some five miles back, 


<a 


* “Explorations in Greenland,” “Choice Literature,” 1884, pp. 170, 253, 
308. 


THE GLACIERS OF GREENLAND. 87 


and then, following the irregularities of its rocky substructure, 
suddenly became a steep crevassed hill, ascending in abrupt 
terraces. ‘Then came two intervals of less rugged ice, from 
which the glacier passed into the great mer de glace. 

On ascending a high, craggy hill to the northward, I had a 
sublime prospect of this great frozen ocean, which seems to 
form the continental axis of Greenland—a vast, undulating 
plain of purple-tinted ice, studded with islands, and absolutely 
gemming the horizon with the varied glitter of sun-tipped 
crystal. | 

The discharge of water from the lower surface of the gla- 
cier exceeded that of any of the northern glaciers except that 
of Humboldt and the one near Etah. One torrent on the side 
nearest me overran the ice-foot from two to five feet in depth, 
and spread itself upon the floes for several hundred yards ; 
and another, finding its outlet near the summit of the glacier, 
broke over the rocks and poured in cataracts upon the beach 
below.* 


Between Wolstenholme Sound and Murchison Strait, 
about latitude 76° 60’, Tyndall Glacier comes down to the 
sea in a broad current ten or twelve miles in width; while 
twenty or twenty-five miles to the north, on Northumberland 
Island, a curious glacier is described by Kane, which he 
calls a “ hanging glacier,” and named after his brother John. 
“Tt seemed,” he says, “as if a caldron of ice inside the 
coast-ridge was boiling over, and throwing its crust in huge 
fragments from the overhanging lip into the sea below. The 
glacier must have been eleven hundred feet high ; but even 
at its summit we could see the lines of viscous movement.” + 

Upon another point in this island a glacier was encount- 
ered which affords Dr. Kane opportunity to remark upon 
some points not often noticed. The party had encamped on 
a low beach at the foot of a moraine which came down be- 
tween precipitous cliffs of surpassing wildness. While there, 
he says : 


-* “ Aretic Explorations in the Years 1853, 1854, 1855,” vol. ii, pp. 270-272. 
t+ Ibid., pp. 259, 260. 


Ss — THE ICE AGE IN NORTH AMERICA, 


I was greatly interested by a glacier that occupied the head 
of the moraine. It came down abruptly from the central pla- 
teau of the island, with an angle of descent of more than sey- 
enty degrees. I have never seen one that illustrated more 
beautifully the viscous or semi-solid movement of these masses. 
Like a well-known glacier of the Alps, it had two planes of 
descent : the upper nearly precipitous for about four hundred 
feet from the summit; the lower of about the same height, but 
with an angle of some fifty degrees; the two communicating 
by a shghtly inclined platform perhaps half a mile long. This 
ice was unbroken through its entire extent. It came down from 
the level of the upper country, a vast icicle, with the folds or 
waves impressed upon it by its onward motion undisturbed by 
any apparent fracture or crevasse. Thus it rolled onward over 
the rugged and contracting platform below, and thence poured 
its semi-solid mass down upon the plain. Where it encount- 
ered occasional knobs of rock it passed round them, bearing 
still the distinctive marks of an imperfect fluid obstructed in 
its descent ; and its lower fall described a dome, or, to use 
the more accurate simile of Forbes, a great outspread clam- 
shell of ice. 

It seemed as if an interior ice-lake was rising above the 
brink of the cliffs that confined it. In many places it could 
be seen exuding or forcing its way over the very crest of the 
rocks, and hanging down in huge icy stalactites seventy and 
one hundred feet long. These were still lengthening out by 
the continuous overflow, some of them breaking off as their 
weight became too great for their tenacity, others swelling by 
constant supplies from the interior, but spitting off fragment- 
ary masses with an unremitting clamor. The plain below 
these cataractine glaciers was piling up with the débris, while 
torrents of the melted rubbish found their way, foaming and 
muddy, to the sea, carrying gravel and rocks along with them. 

These ice-cascades, as we called them, kept up their din the 
whole night, sometimes startling us with a heavy booming 
sound, as the larger masses fell, but more generally ratthng 
away like the random fires of a militia parade. On examining 
the ice of which they were made up, I found grains of névé 
larger than a walnut ; so large, indeed, that it was hard to re- 


THE GLACTERS OF GREENLAND. 89 


alize that they could be formed by the ordinary granulating 
processes of the winter snows. My impression is, that the sur- 
face of the plateau-ice, the mer de glace of the island, is made 
up of these agglomerated nodules, and that they are forced out 
and discarded by the advance of the more compact ice from 
higher levels.* 


The winter of 1853 and 1854 was spent by Dr. Kane in Van 
Rensselaer Harbor, in latitude 78° 60’. From this point Dr. 
Hayes and a small party were sent inland for the purpose of 
securing, if possible, some game to eke out their ship-sup- 
plies of food. They reported that, “after penetrating the 
interior about ninety miles, their progress was arrested by a 
glacier four hundred feet high, and extending to the north 
and west as far as the eye could reach.” On his second ex- 
pedition, in 1860, Dr. Hayes penetrated this same region 
again, starting from Port Foulke, about twenty miles to the 
southwest—venturing, this time, some distance out on the 
surface of the glacier. The following is his own vivid de- 
scription of the ice-field, beginning with the narrative of his 
first expedition. 


At length we emerged upon a broad plain or valley, wider 
than any we had yet seen, in the heart of which reposed a 
lake about two miles in length by half a mile in width, over 
the transparent, glassy surface of which we walked. On either 
side of us rose rugged bluffs, that stretched off into long lines 
of hills, culminating in series in a broad-topped mountain- 
ridge, which, running away to right and left, was cut by a gap 
several miles wide that opened directly before us. Immediately 
in front was a low hill, around the base of which flowed upon 
either side the branches of the stream which we had followed. 
Leaving the bed of the river just above the lake, we ascended 
to the top of this hillock ; and here a sight burst upon us, 
grand and imposing beyond any power of mine adequately to 
describe. From the rocky bed, only a few miles in advance, a 
sloping wall of pure whiteness rose to a broad level plain of ice 


* “ Arctic Explorations,” vol. i, pp. 334-336 


90 THE ICE AGE IN NORTH AMERICA, 


which, apparently boundless, stretched away toward the un- 
known east. It was the great mer de glace of the Arctic Con- 
tinent. 

At any subsequent period of the cruise this sight would 
have less impressed me; but I had never, except in the dis- 
tance, seen a glacier. Here before us was, in reality, the 
counterpart of the river-system of other lands. From behind 
the granite hills the congealed drainings of the interior water- 
sheds, the atmospheric precipitations of ages, were moving as 
a solid though plastic mass, down through every gap in the 
mountains, swallowing up the rocks, filling the valleys, sub- 
merging the hills—an onward, irresistible, crystal tide, swell- 
ing to the ocean. Cutting the surface were many vertical 
crevasses, or gutters, some of great depth, which had drained 
off the melted snow. 

It was midnight when we made our approach. The sun 
was several degrees beneath the horizon, and afforded us a 
faint twilight. Stars of the second magnitude were dimly visi- 
ble in the northern heavens. When we were within about 
half a mile of the icy wall, a brilliant meteor fell before us, 
and, by its reflection upon the glassy surface beneath, greatly 
heightened the effect of the scene ; while loud reports, like 
distant thunder or the booming of artillery, broke at intervals 
from the heart of the frozen sea. 

Upon close inspection we found the face of the glacier to 
ascend at an angle of from thirty to thirty-five degrees. At its 
base lay a high snow-bank, up which we clambered about sixty 
feet ; but beyond this the ice was so smooth as to defy our 
efforts. The mountains, which stood like giant gate-posts on 
either side, were overlapped and partially submerged by the 
glacier. From the face of this a multitude of little rivulets 
ran down the gutters already mentioned, or gurgled from be- 
neath the ice, and formed, on the level lands below, a sort of 
marsh, not twenty yards from the icy wall. Here grew, in 
strange contrast, beds of green moss; and in these, tufts of 
dwarf willows were twining their tiny arms and rootlets about 
the feebler flower-growths; and there, clustered together, 
crouched among the grass, and sheltered by the leaves, and 
feeding on the bed of lichens, I found a white-blossomed draba 


. 
{ 
} 
; 
{ 
. 


THE GLACIERS OF GREENLAND. 91 


which would have needed only a lady’s thimble for a flower- 
pot, and a white chickweed. Dotting the few feet of green 
around me were seen the yellow blossoms of the more hardy 
poppy, the purple potentilla, and the white, purple, and yellow 
Saxifrages. 

This little oasis was literally imbedded in ice. The water 
which had flowed through it had frozen in the holes, and 
spread itself out in a crystal sheet upon the rocks and stones 
around. A few specimens of the tiny blossoms were laid in 
my note-book, a sprig of heather and a saxifrage were stuck in 
my button-hole, and with these souvenirs we left this garden- 
spot which the glacier was soon to cover forever from human 
=) ae | 

In the autumn of 1860 I was favored with an opportunity 
to make a more important exploration of this great mer de 
glace, having from my winter harbor at Port Foulke ascer- 
tained that it had broken through the mountain-chain at the 
head of the bay in which my harbor was situated, and was 
there approaching the sea. Up this glacier, which had thus 
forced the rocky ramparts, | made my way with a small party 
of men, attaining an altitude of about 5,000 feet, and extend- 
ing my observations seventy miles from the coast. The jour- 
ney possessed the more value that it was entirely novel as re- 
gards the interior of Greenland. I was finally driven back by 
a severe gale of wind, which, being accompanied by a sudden 
fall of temperature, placed my party, for the time, in great 
jeopardy, as my tent afforded no shelter; but I had gone far 
enough to determine, with some degree of accuracy, the char- 
acter of the interior; and the information thus acquired, in 
connection with my journey with Mr. Wilson in 1853, as just 
related furnishes an important addition to our knowledge of 
the great glacier system of the Greenland Continent. LEast- 
ward from the position attained on both of these journeys no 
mountains were visible—nothing but a uniform inclined plane 
of whiteness, a solid sea of ice, hundreds and hundreds of feet 
in depth, steadily rising until lost in the distance against the 
sky. A full description of the journey of 1860 has been pub- 
lished in my ‘‘ Open Polar Sea.’ 

This vast body of ice, now known as Humboldt Glacier, is 


92 THE ICE AGE IN NORTH AMERICA. 


the largest glacier known, being about sixty miles across, and 
through at least one half of that extent discharging icebergs, 
like the glacier already spoken of as having broken through 
the mountains near Port Foulke, this Humboldt Glacier has 
overcome the mountain-barriers, and poured down into the 
sea between Greenland and Washington Land, which latter is 
probably an island, lying in the expansion of Smith Sound - 
(or Strait, as named by Dr. Kane), the water flowing to the 
eastward of Washington Land being now entirely replaced by 
the glacier. From Humboldt Glacier the face of the mer de 
glace sweeps around behind the mountain-chain in a curve 
toward Port Foulke. At the point reached by Mr. Wilson 
and myself, the ice was breaking through the mountains, 
nearly midway between these two extremes of the curve, and 
will, at some remote period, find its way into Smith Sound 
through the tortuous valley which now forms the bed of Mary 
Minturn River. South of Port Foulke the face of the mer de 
glace forms a series of similar curves of greater or less extent, 
and through all the great valleys of the Greenland coast-range, 
glaciers discharge into Baffin Bay their streams of icebergs. 
Several of these glaciers are from five to twenty miles across, 
and those of Melville Bay are doubtless much more exten- 
sive. * 


This great Humboldt Glacier enters Peabody Bay from 
the east, filling the whole space from latitude 79° to 80°. 
There is, however, a vast movement of glacier-ice toward 
this point from the southeast. The face of the Humboldt 
Glacier is described by Dr. Kane as everywhere, for a 
distance of more than sixty miles, an “abrupt and threat- 
ening precipice, only broken by clefts and deep ravines, 
giving breadth and interest to its wild expression.” t+ The 
party which first saw this majestic ice-front were com- 
pelled to traverse its entire breadth on the ice which had 
formed outside it in the months of September and October. 
A chief peril of their situation arose from the discharging 


* “ An Arctic Boat-Journey,” pp. 10-12, 377, 378. 
+ “ Arctic Explorations,” vol. i, p. 222. 


THE GLACIERS OF GREENLAND. 93 


bergs of the great glacier which broke up the ice for miles 
around, at one time producing, directly under their tent, a 
fissure in the ice on which they had camped for the night. 
Repeatedly they were compelled to ferry themselves over 
the cracks in the ice on the bay by rafts of ice. * 

Kane gives his first impressions of this grand glacier in 
the following vivid description : 7 


I will not attempt to do better by florid description. Men 
only rhapsodize about Niagara and the ocean. My notes speak 
simply of the ‘‘long, ever-shining line of cliff diminished to a 
well-pointed wedge in the perspective” ; and, again, of ‘‘ the 
face of glistening ice, sweeping in a long curve from the low 
interior, the facets in front intensely illuminated by the sun.” 
But this line of cliff rose in a solid, glassy wall 300 feet above 
the water-level, with an unknown, unfathomable depth below 
it ; and its curved face, sixty miles in length from Cape Agas- 
siz to Cape Forbes, vanished into unknown space at not more 
than a single day’s railroad-travel from the pole. The interior, 
with which it communicated and from which it issued, was 
an unsurveyed mer de glace—an ice-ocean, to the eye, of bound- 
less dimensions. 

It was in full sight—the mighty crystal bridge which con- 
nects the two continents of America and Greenland. I say 
continents ; for Greenland, however insulated it may ulti- 
mately prove to be, is in mass strictly continental. Its least 
possible axis, measured from Cape Farewell to the line of this 
glacier, in the neighborhood of the eightieth parallel, gives a 
length of more than 1,200 miles, not materially less than that 
of Australia from its northern to its southern cape. 

Imagine, now, the center of such a continent, occupied 
through nearly its whole extent by a deep, unbroken sea of 
ice that gathers perennial increase from the water-shed of vast 
snow-covered mountains and all the precipitations of its atmos- 
phere upon its own surface. Imagine this, moving onward 
like a great glacial river, seeking outlets at every fiord and 
valley, rolling icy cataracts into the Atlantic and Greenland 


* “ Arctic Explorations,” vol. i, p. 135. 


94 THE ICH AGH IN NORTH AMERICA. 


seas; and, having at last reached the northern limit of the 
land that has borne it up, pouring out a mighty frozen tor- 
rent into unknown arctic space. 

It is thus, and only thus, ‘that we must form a just concep- 
tion of a phenomenon like this great glacier. I had looked in 
my own mind for such an appearance, should I ever be fortu- 
nate enough to reach the northern coast of Greenland. But, 
now that it was before me, I could hardly realize it. I had 
recognized, in my quiet library at home, the beautiful analo- 
gies which Forbes and Studer have developed between the 
glacier and the river. But I could not comprehend, at first, 
this complete substitution of ice for water. 

It was slowly that the conviction dawned on me that I was 
looking upon the counterpart of the great river-system of Arc- 
tic Asia and America. Yet here were no water-feeders from 
the south. Every particle of moisture had its origin within 
the polar circle, and had been converted into ice. There were 
no vast alluvions, no forest or animal traces borne down by 
liquid torrents. Here was a plastic, moving, semi-solid mass, 
obliterating life, swallowing rocks and islands, and plowing 
its way with irresistible march through the crust of an invest- 
ing sea.* 


The following summer Dr. Kane visited the scene again, 
and gives many additional particulars : 


I had not [he writes] realized fully the spectacle of this 
stupendous monument of frost. I had seen it for some hours 
hanging over the ice like a white-mist cloud, but now it rose 
up before me clearly defined and almost precipitous. The 
whole horizon, so vague and shadowy before, was broken by 
long lines of icebergs; and as the dogs, cheered by the cries 
of their wild drivers, went on, losing themselves deeper and 
deeper in the labyrinth, it seemed like closing around us the 
walls of an icy world. They stopped at last; and I had time, 
while my companions rested and fed, to climb one of the high- 
est bergs. The atmosphere favored me: the blue tops of 
Washington Land [to the north] were in full view, and, 


* “ Arctic Explorations,” vol. i, pp. 225-228. 


THE GLACIERS OF GREENLAND. 95 


losing itself in a dark water-cloud, the noble head-land of John 
Barrow. 

The trend of this glacier is a few degrees to the west of 
north. We followed its face afterward, edging in for the 
Greenland coast, about the rocky archipelago which I have 
named after the Advance. From one of these rugged islets, 
the nearest to the glacier which could be approached with any- 
thing like safety, I could see another island, larger and closer 
in shore, already half covered by the encroaching face of the 
glacier, and great masses of ice still detaching themselves and 
splintering as they fell upon that portion which protruded. 
Repose was not the characteristic of this seemingly solid mass ; 
every feature indicated activity, energy, movement. 

The surface seemed to follow that of the basis-country over 
which it flowed. It was undulating about the horizon, but 
as it descended toward the sea it represented a broken plain 
with a general inclination of some nine degrees, still dimin- 
ishing toward the foreground. Crevasses, in the distance mere 
wrinkles, expanded as they came nearer, and were crossed 
almost at right angles by long, continuous lines of fracture 
parallel with the face of the glacier. 

These lines, too, scarcely traceable in the far distance, 
widened as they approached the sea until they formed a gigan- 
tic stairway. It seemed as though the ice had lost its support 
below, and that the mass was Jet down from above in a series 
of steps. Such an action, owing to the heat derived from the 
soil, the excessive surface-drainage, and the constant abrasion 
of the sea, must in reality take place. My note-book may 
enable me at some future day to develop its details. I have 
referred to this as the escaladed structure of the arctic gla- 
cer. 

The indication of a great propelling agency seemed to be 
just commencing at the time I was observing it. These split- 
off lines of ice were evidently in motion, pressed on by those 
behind, but still widening their fissures, as if the impelling 
action was more and more energetic nearer the water, till at 
last they floated away in the form of icebergs. Long files of 
these detached masses could be traced slowly sailing off into 
the distance, their separation marked by dark parallel shadows 


96 THE ICR AGE IN NORTH AMERICA. 


—broad and spacious avenues near the eye, but narrowed in 
the perspective to mere lines. A more impressive illustration 
of the forces of Nature can hardly be conceived. .. . 

The frozen masses before me were similar in structure to 
the Alpine and Norwegian ice-growths. It would be foreign 
to the character of this book to enter upon the discussion 
which the remark suggests ; but it will be seen by the sketch, 
imperfect as it is, that their face presented nearly all the char- 
acteristic features of the Swiss Alps. The ‘‘overflow,” 
have called the viscous overlapping of the surface, was more 
clearly marked than upon any Alpine glacier with which I am 
acquainted. When close to the island-rocks, and looking out 
upon the upper table of the glacier, 1 was struck with the 
homely analogy of the batter-cake spreading itself out under 
the ladle of the housewife, the upper surface less affected by 
friction, and rolling forward in consequence. 

The crevasses bore the marks of direct fracture and the 
more gradual action of surface-drainage. ‘The extensive water- 
shed between their converging planes gave to the icy surface 
most of the hydrographic features of a river-system. ‘The ice- 
born rivers which divided them were margined occasionally 
with spires of discolored ice, and generally lost themselves in 
the central areas of the glacier before reaching its foreground. 
Occasionally, too, the face of the glacier was cut by vertical 
lines, which, as in the Alpine growths, were evidently outlets 
for the surface-drainage. Everything was, of course, bound 
in solid ice when I looked at it ; but the evidences of torrent- 
action were unequivocal, and Mr. Bonsall and Mr. Morton, at 
their visits of the preceding year, found both cascades and 
water-tunnels in abundance. 

The height of this ice-wall at the nearest point was about 
three hundred feet, measured from the water’s edge; and the 
unbroken right line of its diminishing perspective showed 
that this might be regarded as its constant measurement. It 
seemed, in fact, a great icy table-land, abutting with a clean 
precipice against the sea. This is, indeed, characteristic of 
all those arctic glaciers which issue from central reservoirs, or 
mers de glace, upon the fiords or bays, and is strikingly in con- 
trast with the dependent or hanging glacier of the ravines, 


as L 


ee 


THE GLACIERS OF GREENLAND, O¢ 


where every line and furrow and chasm seems to indicate the 
movement of descent and the mechanical disturbances which 
have retarded it. | 

I have named this great glacier after Alexander von Hum- 
boldt, and the cape which flanks it on the Greenland coast 
after Professor Agassiz. 

The point at which this immense body of ice enters the 
land of Washington gives even to a distant view impressive 
indications of its plastic or semi-solid character. No one could 
resist the impression of fluidity conveyed by its peculiar mark- 
ings. I have named it Cape Forbes, after the eminent crystal- 
ologist whose views it so abundantly confirms. 

As the surface of the glacier receded to the south, its face 
seemed broken with piles of earth and rock-stained rubbish, 
till far back in the interior it was hidden from me by the slope 
of a hill. Still beyond this, however, the white blink or glare 
of the sky above showed its continued extension. 

It was more difficult to trace this outline to the northward, 
on account of the immense discharges at its base. The talus 
of its descent from the interior, looking far off to the east, 
ranged from seven to fifteen degrees, so broken by the crevasses, 
however, as to give the effect of an inclined plane only in the 
distance. A few black knobs rose from the white snow, like 
islands from the sea. 

The general configuration of its surface showed how it 
adapted itself to the inequalities of the basis-country beneath. 
There was every modification of hill and valley, just as upon 
land. Thus diversified in its aspect, it stretches to the north 
till it bounds upon the new land of Washington, cementing 
into one the Greenland of the Scandinavian Vikings and the 
America of Columbus.* 


Much less is known concerning the eastern coast of Green- 
land than about the western coast. For a long time it was 
supposed: that there might be a considerable population in 
the lower latitudes along the eastern side. But that is now 
proved to be a mistake. The whole coast is very inhos- 


* “ Aretic Explorations,” vol. ii, pp. 146-153. 


98 THE ICE AGE IN NORTH AMERICA. 


pitable and difficult of approach. From latitude 65° to lati- 
tude 69° little or nothing is known of it. In 182223 
Scoresby, Cleavering, and Sabine, hastily explored the coast 
from latitude 69° to 76°, and reported numerous glaciers 
descending to the sea-level through extensive fiords, from 
which immense icebergs float out and render navigation dan- 
gerous. In 1869 and 1870 the second North German Expe- 
dition partially explored the coast between latitude 73° and 
77°. Mr. Payer, an experienced Alpine explorer, who ac- 
companied the expedition, reports the country as much 
broken, and the glaciers as “subordinated in position to the 
higher peaks, and having their moraines, both lateral and 
terminal, like those of the Alpine ranges, and on a still 
grander scale.” Petermann Peak, in latitude 73°, is reported 
as 18,000 feet high. Captain Koldewey, chief of the expe- 
dition, found extensive plateaus on the mainland, in latitude 
75°, to be “entirely clear of snow, although only sparsely 
covered with vegetation.” The mountains in this vicinity, 
also, rising to a height of more than 2,000 feet, were free: 
from snow in the summer. Some of the fiords in this vicin- 
ity penetrate the continent through several degrees of longi- 
tude. An interesting episode of this expedition was the 
experience of the crew of the ship Hansa, which was caught 
in the ice and destroyed. The crew, however, escaped by 
encamping on the ice-floe which had crushed their ship. 
From this, as it slowly floated toward the south through sev- 
eral degrees of latitude, they had opportunity to make many 
important observations upon the continent itself. As viewed 
from this unique position, the coast had the appearance every- 
where of being precipitous, with mountains of considerable 
height rising in the background, from which numerous small 
glaciers descended to the sea-level. | 

In 1888 Dr. F. Nansen, with Lieutenant Sverdrup and 
four others, was left by a whaler on the ice-pack bordering, 
the east of Greenland about latitude 65°, and in sight of the 
coast. For twelve days the party was on the ice-pack float- 
ing south, and so actually reached the coast only about lati- 


THE GLACIERS OF GREENLAND. 99 


tude 64°. From this point they attempted to cross the inland 
ice in a northwesterly direction toward Christianshaab. They 
soon reached a height of 7,000 feet, and were compelled by 
severe northerly storms to diverge from their course, taking 
a direction more to the west. The greatest height attained 
was 9,500 feet, and the party arrived on the western coast at 
Ameralik Fiord, a little south of Gotthaab, about the same 
latitude at which they entered. 


In 1892, and again in 1895, Lieutenant Robert E. Peary 
set out from Inglefield Gulf (latitude 77° 40’), and traveling 
in a northeasterly direction for a distance of something over 
five hundred miles, crossed the Greenland ice-sheet, and came 
out near latitude 82° and longitude 40°. He succeeded in 
-wapping a considerable portion of the northern coast, and 
in demonstrating that Greenland is really an island, with 
smaller islands to the north. Glaciers were found here flow- 
ing to the north, while there was much vegetation supporting 
herds of musk-ox and other forms of life. The interior ice 
was found to be of a pretty uniform height, ranging from 
5,000 to 9,000 feet above tide. Indeed, the conditions did 
not materially differ from those found by Nansen fifteen de- 
grees farther south. 


In 1907 M. Erichsen, in charge or a Danish expedition, 
pushed his vessel up the east coast of Greenland to 77° 
north latitude, near Cape Bismarck, from which point he 
explored the territory northward to Independence Bay, 
thus completing the survey of thecontinent. Butalthoughhe 
lost his life in the effort, his notes were complete and showed 
to the surprise of all that beyond the 78th parallel the coast 
trended northeast instead of northwest, extending towards 
Spitsbergen until the opening between the Arctic and Atlantic 
Oceans is narrowed to 240 miles, only one-third the width 
that had been formerly supposed to exist. 

In the summer of 1909, both Frederick A. Cook and Rob- 
ert E. Peary laid claims to having reached the north pole, 
both explorers claiming to have set out from the northern 
part of Grant Land, Cook in 1908 and Peary in 1909. Both 


100 THE ICE. AGE IN NORTH AMERICA. 


agree in their reports that there was smooth ice beyond the 
88th parallel, in which rapid traveling could be accomplished, 
Peary alleging that he made the last 130 geographical miles 
in five forced marches, reaching the pole April 6, 1909. All 
was ice with no land in sight. Temperatures ranged from 
12—° to -33° with cloudless sky. The return journey of 413 | 
geographical miles was made in 16 days. A single imperfect 
sounding disclosed the existence of a deep ocean in close 
proximity to the pole. The reports of Cook, made previously 
to those of Peary, revealed almost identical conditions. 
Among the most instructive observations upon the Green- 
land glaciers were those made in 1880 by Dr. N. O. Holst of 
the Swedish Geological Survey. These were made on the 
Frederickshaab Glacier in latitude 62° 32’, and have a most 
important bearing upon the mode of the accumulation of 
moraines of all sorts. He found extensive deposits of both 
englacial and subglacial drift, respectively characterized by 
angular and glaciated stones and bowlders. The largest 
accumulation of superglacial drift, which had been englacial, 
was observed on the southern edge of the lobe. The drift 
covering the ice-surface here, as exposed by the ablation or 
superficial melting, was ascertained to extend alonga distance 
of nearly twelve miles, and to reach half a mile to a mile and 
a half upon the ice. The quantity and upper limit of the 
superglacial drift at this locality are given by him as follows: 


Its thickness is always greatest near land, but here it is 
often quite difficult to estimate its actual thickness, as it 
sometimes forms a compact covering, only in some fissures 
showing the underlying ice. This uneven thickness of moraine 
cover offers to the ice a proportionally varying protection 
against the sun. It thus happens that the unequal thawing 
moulds the underlying surface of the ice into valleys and hills, 
‘the latter sometimes arising to a height of fifty feet above 
the adjacent valley, and being so densely covered with morainic 
material that this completely hides the ice core. Which, how- 
-ever, often forms the main part of the hill. 


THE GLACIERS OF GREENLAND. 101 


Farther in on the ice the moraine gradually thins out. At 
the locality just referred to the moraine cover, 3,000 feet 
from land, measured several inches in depth; still the ice was 
seen in some bare spots. Beyond 4,000 feet from land the 
moraine formed no continuous cover, and at 8,300 feet it 
ceased entirely, with a perceptible limit against clear ice. 
Only some scattered spots of sand and gravel were met with 
even a few hundred feet farther in on the ice. 

The average thickness of the moraine taken across its 
entire width near its eastern end is estimated at from one to 
two feet. The limit between the moraine cover and the pure 
ice is always located at a considerable though varying ele- 
vation above the edge of the inland ice. In the instance of 
the above mentioned moraine it varied between 200 feet and 
500 feet. 

The ice within 100 feet of its borders invariably presents 
a slope towards the border, though generally not so steep as 
to render the ascent at all difficult. Farther in, the slope is 
much less marked, though there appears to exist a general 
rising towards the east, while the surface everywhere presents 
vast undulations. The border of the ice appears to have 
retreated quite recently in many places; in others it had 
evidently advanced . . . . On the surface the inland ice 
either presented the appearance of a compact mass of coarse 
erystallinic texture, reminding one of the grains of common 
rock candy, or else it is honeycombed by the solar heat and 
shows intersecting systems of parallel plates, apparently 
the remnants of large ice crystals, often several inches long, 
which have wasted away, only leaving the frame as it were, 
on which they were built. These plates cr tablets are highly 
mirroring, reflecting the solar rays in all directions, depending 
on the position of each individual crystal.* 


These observations respecting the height of the englacial 
till in the ice correspond closely to those of Professor Russell 
on the Malaspina Glacier in Alaska, and those of Professor 


* “American Naturalist,’’ vol. xxii, pp. 589-598 and 705-713, July and 
August, 1888. 


102 THE ICE AGE IN NORTH AMERICA. 


T. C. Chamberlin, hereafter to be noted, in northern Green- 
land. - 

Some most remarkable facts concerning the termination 
of numerous glaciers in northern Greenland and in Grinnell 
Land and Ellsmere Land on the other side of Smith Sound are 
reported by Professor Chamberlin and by General A. W. 
Greely.* In both these regions the glaciers often terminate 
in perpendicular, or projecting ice cliffs. So extensive and 
marked are these in Ellsmere Land that they were termed the 
‘““Chinese Wall.”’ They extend across the country in an 
east and west direction and form an escarpment from 200 to 
300 feet high. Over the crest of the wall appear the snow 
fields and snow covered mountains where the glacier has its 
source. 

The explanation of this peculiar phenomenon is to be 
found partly in the fact that the upper strata of the ice 
move faster than the lower, tending to form a “breaker” 
in the ice, such as appears on the crest of an incoming wave. 
Partly also, as suggested by Professor Chamberlin, because 
the low angle at which the sun’s rays strike the ice causes 
them to melt the lower dirt laden strata which attract the 
heat, faster than the purer strata found near the top of the 
ice. 


*A. W. Greely, ‘‘Report of Proceedings of U. 8. Expedition to Lady 
Franklin Bay,’’ Washington, 1888, vol. i, pp. 274-296. 


Fic. 34—Sea margin of Cornell Glacier, Greenland. (Tarr). 


Fie. 35—Glacier in North Greenland, showing the upper strata of ice rolling over like 
breakers. (Photographed by Chamberlin). 


CHAPTER V. 
GLACIERS IN OTHER PARTS OF THE WORLD. 


BzroreE finally concentrating our attention upon the 
ancient glaciated area of North America, it will be profit- 
able to take a glance at existing glaciers in other parts of 
the world. As is well known, glaciers still envelop the 
island of Spitzbergen and linger in the mountains of Nor- 
way and Sweden, of central Europe, ard of southern Asia. 
Vast glaciers also come down to the sea-level in Patagonia, 
and appear higher up upon the mountains of southern Chili. 
The mountains of New Zealand* likewise contain numerous 
groups of glaciers nearly as extensive as those of the Alps. 
The so-called Antarctic Continent would seem to be covered 
with one vast sheet of ice pressing outward, and breaking off 
into immense icebergs. 

The glaciers of tlie Alps have been so frequently described 
that only a few words need be devoted to them here. It is 
estimated that there are as many as four hundred glaciers in 
the Alpine range between Mont Blane and Tyrol, and that, 
all told, they cover an area of more than 1,400 square miles. 
In many places the ice is estimated to be 600 feet in thick- 
ness. The Aletsch Glacier, in the Bernese Oberland, is the 
longest in the Alps, being not far from twenty miles. Many 
others are ten miles or more in length, and are often in certain 
portions of their course from one mile to one mile and a half 
wide. The line of perpetual snow in the Alps is something: 


* See Whitney’s ‘‘ Climatic Changes,” pp. 269-274, to which we are largely 
indebted for the facts presented in this chapter. 


“ 


GLACIERS IN OTHER PARTS OF THE WORLD. 105 


more than 7,500 feet above the sea. The glaciers extend 
from 4,000 to 5,000 feet lower, though the limit is by no 


Fic. 36.—Morteratsch Glacier, Grisons Alps. This glacier advances abont seven inches 
per year. Centuries ago chalets stood a mile farther up the valley. In 1868 frag- 
ments of these ancient dwellings were washed out from underneath the ice. 


means constant from year to year. ‘“ M. Forel reports, from 
the data which he has collected with much care, that there 
have been in this century five periods in the Alpine glaciers : 
of enlargement, from 1800 (?) to 1815 ; of diminution, from 
1815 to 1830; of enlargement, from 1830 to 1845; of dimi- 
nution, from 1845 to 1875; and of enlargement, again, from 
1875 onward. He remarks further that these periods cor- 
respond with those deduced by Mr. C. Lang for the variations 
for the precipitations and temperature of the air; and, con- 
sequently, that the enlargement of the glaciers has gone for- 


anil 


106 THE 1CE AGE IN NORTH AMERICA. 


ward in the cold and rainy period, and the diminution in 
the warm and the dry (‘ Archives Sci. Phys. Nat.,’ May 15, 
18869 2 

The glaciers of Scandinavia, with their snow-fields, are 
estimated to cover a space of about 5,000 square miles. The 


Fie. 37.—The Svartisen Glacier on the west coast of Norway, just within the Arctic cir- 
cle, at the head of a fiord ten miles from the ocean. Mouth of the glacier one mile 
wide, and a quarter of a mile back from the water. Terminal moraine in front. 
(Photographed by Dr. L. C. Warner.) 


mountains are less lofty than the Alps, the greatest altitude 
being about 8,500 feet. But the more northern latitude and 
the moist climate are favorable to the production of glaciers. 
The largest single snow-tield is that of Justedal, in latitude 
62°, occupying a plateau about 5,000 feet above the sea-level, 
and an area of 580 square miles. From this plateau twenty- 
four glaciers descend through the gorges leading toward the 
North German Sea, the largest of which is about five miles 
long and three quarters of a mile wide. The Fondalen snow- 
field, in latitude 66° or 67°, is of nearly the same size with 


* “ American Journal of Science,’ vol. exxxii, 1886, p. 77- 


GLACIERS IN OTHER PARTS OF THE WORLD. 107 


the preceding, and from it glaciers descend to the ocean-level. 
The Folgefon snow-field, still farther north, occupies an area 
of about one hundred square miles, from which three glaciers 
of about the same rank as the preceding descend to the sea. 
To the north of the Scandinavian Peninsula the islands of 
Spitzbergen, Nova Zembla, and Franz-Josef Land, all lying 
above latitude 70°, and the latter north of latitude 80°, are 
deeply covered with glacial ice in their higher portions. 
Speaking of Magdalena Bay in Spitzbergen, Dr. G. Hartwig 


writes: 


Four glaciers reach down this noble inlet - one, called the 
Wagon-Way, is 7,000 feet across at its terminal cliff, which is 
300 feet high, presenting a magnificent wall of ice. But the 
whole scene is constructed on so colossal a scale that it is only 
on a near approach that the glaciers appear in all their impos- 
ing grandeur. . . . Besides the glaciers on Magdalena Bay, 
Spitzbergen has many others that protrude their crystal walls 
down to the water’s edge ; and yet but few icebergs, and the 
largest not to be compared with the productions of Baffin 
_ Bay, are drifted from the shores of Spitzbergen into the open 
sea. The reason is that the glaciers usually terminate where 
the sea is shallow, so that no very large mass if dislodged can 
float away, and they are at the same time so frequently dismem- 
bered by heavy swells that they can not attain any great size.* 


The edge of the coast of the island of Franz-Josef Land 
is quite generally formed by the precipitous ends of glaciers 
a hundred feet or more in height and of unknown depth. 

Iceland, too, has its glaciers in its more elevated portions, 
though nowhere do they come down to the sea-level. The 
snow-tield of Vatna Jékull, with an extreme elevation of 
6,000 feet, has an area of 3,000 square miles. From recent 
reports it would seem that the glaciers of Iceland have for 
some time been rapidly advancing. 

In Asia glaciers are found to a limited extent in the 
Caucasus Mountains, especially near the central portion of 


* “ Polar World,” pp. 135, 136. 


108 THE ICH AGE IN NORTH AMERICA. 


the range, where for a distance of 120 miles the average 
height is 12,000 feet, while several individual peaks rise 
higher than 16,000 feet. 'The snow-line in this range is from 
11,000 to 12,000 feet above the sea-level, and in no case do 
the glaciers descend much lower than the 6,000-foot level. 
The Ural Mountains—owing probably to their being so nar- 
row as not to afford space for large snow-fields—are entirely 
without glaciers. In Central Asia, however, where peaks in 
many cases rise upwards of 20,000 feet, glaciers appear on a 
grand scale in the Hindu Kush, the Tian Shan and the Altai 
mountains and in those surrounding the Pamir. While 
in the Himalayan range, about the head of the Indus, glaciers 
of great size are reported. That at the head of the Basha 
River ‘‘is over thirty miles in length, its lower part, for a 
distance of twenty or twenty-five miles, being about a 
mile and a half in width; above this—for some distance 
at least—it is still wider, a marked feature being its small 
inclination; along a large portion of its course it has an angle 
of slope of not over one and a half or two degrees. 

“At the head of the Braldu Valley, an easterly tributary 
of the Shigar, is one of the largest known glaciers—that of 
Baltoro. This is said by the officers of the survey to be 
thirty-five miles in length, ‘ measured along a central line from 
its termination up to peak K®’ The Biafo Glacier, the foot 
of which is about ten miles west of the Baltoro, is said to be 
over forty miles long.” * 

At the heads of the Sutlej and the Ganges similar glacial 
developments are witnessed, as well as at various other points 
throughout the whole length of the range. 

Passing to South America, we find, according to the best 
reports, that until reaching the southern border of Chili gla- 
ciers are infrequent and relatively small. According to Mr. 
Whymper, no glaciers in Equador descend as low as 12,000 
feet above the sea, and the glaciers in that region are largest 
on the eastern side. Only on Cotopaxi, Chimborazo, and Ilin- 


* Whitney’s ‘ Climatic Changes,” pp. 284, 285. 


GLACIERS IN OTHER PARTS OF THE WORLD. 109 


issa are the glaciers comparable to those on Mont Blane. 
In Chili, in the province of Colchagua, about latitude 35°, 
glaciers begin to appear, descending somewhat below the 
6,000-foot level. ‘*‘ Proceeding southward from Colchagua, we 
pass into a region in which the climatic conditions are very 
different from those prevailing in the country farther north. 
- The ranges border the sea very closely, the amount of pre- 
cipitation increasing and becoming more generally distributed 
throughout the year. The temperature, at the same time di- 
minishes, and all the conditions favorable to the formation of 
glaciers are found to prevail. In consequence of this, there is 
an extensive display of snow and ice along the southern coast 
of Chili, and especially at the very extremity of the conti- 
nent.” 

“In Tierra del Fuego,” writes Mr. Darwin, “the snow- 
Ime descends very low, and the mountain sides are abrupt ; 
therefore we might expect to find glaciers extending far 
down their flanks. Nevertheless, when on first beholding, in 
the middle of summer, many of the creeks on the northern 
side of the Beagle channel terminated by bold precipices of 
ice overhanging the salt water, I felt greatly astonished ; for 
the mountains from which they descended were far from 
being very lofty.” * 

Darwin’s observations upon the Pacer of South America 
are still standard, and are worthy of fuller reproduction. In 
his “ Voyage of ae Beagle ” he says: 


The descent of glaciers to the sea must, I conceive, mainly 
depend (subject, of course, to a proper supply of snow in the 
upper region) on the lowness of the line of perpetual snow on 
steep mountains near the coast. As the snow-line is so low in 
Tierra del Fuego, we might have expected that many of the 
glaciers would have reached the sea. Nevertheless, I was as- 
tonished when I first saw a range, only from 3,000 to 4,000 
feet in height, in the latitude of Cumberland, with every val- 
ley filled with streams of ice descending to the sea-coast. 


* Whitney’s “‘ Climatic Changes,” pp. 272, 278. 


110 THE ICE AGE IN NORTH AMERICA. 


Almost every arm of the sea which penetrates to the interior 
higher chain, not only in Tierra del Fuego, but also on the 
coast for 650 miles northward, is terminated by ‘‘ tremendous 
and astonishing glaciers,” as described by one of the officers 
on the survey. Great masses of ice frequently fall from these 
icy cliffs, and the crash reverberates, like the broadside of a 
man-of-war, through the lonely channels. These falls pro- _ 
duce great waves, which break on the adjoining coasts. It is 
known that earthquakes frequently cause masses of earth to 
fall from sea-cliffs : how terrific, then, would be the effect of 
a severe shock (and such occur here) on a body like a glacier, 
already in motion, and traversed by fissures! I can readily 
believe that the water would be fairly beaten back out of the 
deepest channel, and then, returning with an overwhelming 
force, would whirl about huge masses of rock like so much 
chaff. In Eyre’s Sound, in the latitude of Paris, there are 
immense glaciers, and yet the loftiest neighboring mountain is 
only 6,200 feet high. In this sound about fifty icebergs were 
seen at one time floating outward, and one of them must have 
been at least 168 feet in total height. Some of the icebergs 
were loaded with blocks of no inconsiderable size, of granite 
and other rocks, different from the clay-slate of the surround- 
ing mountains. ‘The glacier farthest from the pole, surveyed 
during the voyages of the Adventure and Beagle, is in latitude 
46° 50’, in the Gulf of Penas. It is fifteen miles long, and in 
one part seven broad, and descends to the sea-coast. But even 
a few miles northward of this glacier, in the Laguna de San 
Rafael, some Spanish missionaries encountered ‘‘ many ice- 
bergs, some great, some small, and others middle-sized,” in a 
narrow arm of the sea, on the 22d of the month correspond- 
ing with our June, and in a latitude corresponding with that 
of the Lake of Geneva ! 

In Europe, the most southern glacier which comes down to 
the sea is met with, according to Von Buch, on the coast of 
Norway, in latitude 67°. Now, this is more than 20° of lati- 
tude, or 1,230 miles, nearer the pole than the Laguna de San 
Rafael. The position of the glaciers at this place and in the 
Gulf of Penas may be put even in a more striking point of 
view, for they descend to the sea-coast, within 74° of latitude, 


GLACIERS IN OTHER PARTS OF THE WORLD. {11 


or 450 miles, of a harbor, where three species of oliva, a voluta. 
and a terebra are the commonest shells, within less than 9° 
from where palms grow, within 4$° of a region where the 
jaguar and puma range over the plains, less than 24° from 
arborescent grasses, and (looking to the westward in the same 
. hemisphere) less than 2° from orchidaceous parasites, . and 
within a single degree of tree-ferns ! * 


Mr. Darwin’s experience was so similar to that of those 
who visit Alaska (see Chapter III, page 50), that another 
extract will prove especially instructive by way of compari- 
son. Speaking of the Straits of Magellan, he says: 


The lofty mountains on the north side compose the granitic 
axis, or backbone of the country, and boldly rise to a height 
of between 3,000 and 4,000 feet, with one peak above 6,000 
feet. They are covered by a wide mantle of perpetual snow, 
and numerous cascades pour their waters, through the woods, 
into the narrow channel below. In many parts, magnificent 
glaciers extend from the mountain-side to the water’s edge. 
It is scarcely possible to imagine anything more beautiful than 
the beryl-like blue of these glaciers, and especially as contrasted 
with the dead white of the upper expanse of snow. ‘The frag- 
ments which had fallen from the glacier into the water were 
floating away, and the channel, with its icebergs, presented for 
the space of a mile a miniature likeness of the Polar Sea. The 
boats being hauled on shore at our dinner-hour, we were ad- 
miring from the distance of half a mile a perpendicular cliff 
of ice, and were wishing that some more fragments would fall. 
At last down came a mass with a roaring noise, and imme- 
diately we saw the smooth outline of a wave traveling toward 
us. The men ran down as quickly as they could to the boats ; 
for the chance of their being dashed to pieces was evident. 
One of the seamen just caught hold of the bows as the curling 
breaker reached it. He was knocked over and over, but not 
hurt ; and the boats, though thrice lifted on high and let fall 
again, received no damage. This was most fortunate for us, 
for we were a hundred miles distant from the ship, and we 


* “ Voyage of the Beagle,” edition of 1872, pp. 245-247. 


112 THE ICH AGE IN NORTH AMERICA. 


should have been left without provisions or fire-arms. I had 
previously observed that some large fragments of rock on the 
beach had been lately displaced, but, until seeing this wave, 
I did not understand the cause. One side of the creek was 
formed by a spur of mica-slate ; the head by a cliff of ice about 
forty feet high ; and the other side by a promontory fifty feet . 
high, built up of huge rounded fragments of granite and mica- 
slate, out of which old trees were growing. This promontory 
was evidently a moraine, heaped up at a period when the gla- 
cier had greater dimensions. * 


Of the glaciers of New Zealand the following succinct 
account of Whitney must suffice: 


On the western coast of the southern island, between the 
parallels of 42° and 45°, rises abruptly from the sea a grand 
range of mountains, the culminating point of which, Mount 
Cook, is about 13,000 feet in elevation. Along this chain, for 
a length of about one hundred miles, are developed numerous 
eroups of glaciers, some of which are not much inferior in size 
to the largest of those of the Alps. The Tasman Glacier is 
said by Haast, who first scientifically explored and described 
these mountains, to be ten miles in length and a mile and 
three quarters broad at its termination, the lower portion, for 
a distance of three miles, being covered with morainic de- 
tritus. + . 


Glacial conditions prevail over the Antarctic Continent. 
Icebergs of great size are frequently encountered up to 58° 
south latitude, in the direction of Cape Horn, and as far as 
latitude 33° in the direction of Cape of Good Hope. The 
number and size of these, of which more particulars will be 
given presently, are such as to necessitate an extensive area 
of glaciers about the south pole. Much of all that is known 
of the Antarctic Continent was discovered by Sir J. CO. 
Ross during the period extending from 1839 to 1843, when, 
between the parallels of 70° and 78° south latitude, he en- 


* “Voyage of the Beagle,” edition of 1872, pp. 224, 225. 
+ “Climatic Changes,” pp. 278, 274. 


GLACIERS IN OTHER PARTS OF THE WORLD. 113 


gountered in his explorations a precipitous mountain-coast, 
rising from 7,000 to 10,000 feet above tide. Through the 
valleys intervening between the mountain-ranges huge gla- 
ciers descended, and “ projected in many places several miles 
into the sea, and terminated in lofty perpendicular cliffs. 
In a few places the rocks broke through their icy covering, 
by which alone we could be assured that land formed the 
nucleus of this, to appearance, enormous iceberg.” * 

Again, speaking of the region in the vicinity of the lofty 
voleanoes Terror and Erebus, between 10,000 and 12,000 feet 
high, the same navigator says : 


“We perceived a low white line extending from its extreme 
eastern point as far as the eye could discern to the eastward. 
It presented an extraordinary appearance, gradually increasing 
in height as we got nearer to it, and proving at length to bea 
perpendicular cliff of ice, between 150 and 200 feet above the 
level of the sea, perfectly flat and level at the top, and with- 
out any fissures or promontories on its even seaward face. 
What was beyond it we could not imagine; for, being much 
higher than our mast-head, we could not see anything except 
the summit of a lofty range of mountains extending to the 
southward as far as the seventy-ninth degree of latitude. 
These mountains, being the southernmost land hitherto dk- 
covered, I felt great satisfaction in naming after Sir Edward 
Parry. . . . Whether Parry Mountains again take an easterly 
trending and form the base to which this extraordinary mass 
of ice is attached, must be left for future navigators to deter- 
mine. If there be land to the southward, it must be very 
remote, or of much less elevation than any other part of the 
coast we have seen, or it would have appeared above the bar- 
rier.” | . 

This ice-cliff or barrier was followed by Captain Ross as far 
as 198° west longitude, and found to preserve very much the 
same character during the whole of that distance. On the 
lithographic view of this great ice-sheet given in Ross’s work 
it is described as “‘part of the South Polar Barrier. to 180 


* Quoted by Whitney in “ Climatic Changes,” p. 314. 


114 THE ICE AGE IN NORTH AMERICA. 


feet above the sea-level, 1,000 feet thick, and 450 miles in 
length.” 

A similar vertical wall of ice was seen by D’Urville, off the 
coast of Adelie Land. He thus describes it: ‘‘ Its appearance 
was astonishing. We perceived a cliff having a uniform eleva- 
tion of from 100 to 150 feet, forming a long line extending off 
to the west. . . . Thus for more than twelve hours we had 
followed this wall of ice, and found its sides everywhere per- 
fectly vertical and its summit horizontal. Not the smallest 
irregularity, not the most inconsiderable elevation, broke its 
uniformity, for the twenty leagues of distance which we fol- 
lowed it during the day, although we passed it occasionally at 
a distance of only two or three miles, so that we could make 
out with ease its smallest irregularities. Some large pieces of 
ice were lying along the side of this frozen coast ; but, on the 
whole, there was open sea in the offing.” * 


In addition to the recent direct observations upon the 
glaciers of the Antarctic Continent, we are permitted to 
turn to an important source of indirect evidence furnished 
by the icebergs encountered in the region. Many of these 
are of such size as to indicate an enormous depth to the glacial 
ice of which they are fragments, and imply the existence of 
a glaciated area larger even than Greenland. In reading the 
accounts of icebergs we should bear in mind that the specitie 
gravity of ice is such that where there is one cubic foot of 
an iceberg above the water’s surface there are seven or eight 
cubic feet below the surface: so that, if the form of the berg 
could be supposed to be symmetrical, we should multiply 
the height of the berg above water by eight or nine to get 
its perpendicular dimension. But as the forms of the ice- 
bergs are usually irregular, this rule can not always be ap- 
plied. In several of the instances te be referred to, however, 
the masses are so large, and the forms so regular, that we 
can not be far amiss in applying the rule. Some of these 
masses of floating ice are of almost incredible size, and their 


* Quoted by Whitney in “ Climatic Changes,” pp. 315, 316. 


GLAVUIERS IN OTHER PARTS OF THE WORLD. 115 


origin can only have been upon large surfaces of land in 
every way favorably situated for the accumulation of snow 
and the formation of glaciers. The following are a few of 
the examples reported a century ago by Captain Cook : 


At eight o’clock saw an island of ice to the westward 
of us, being then in the latitude of 50° 40’ south, and longi- 
tude 2° 0’ east of the Cape of Good Hope. Soon after, the 
wind moderated, and we let all the reefs out of the top-sails, 
got the sprit-sail-yard out, and top-gallant-mast up. ‘The 
weather coming hazy, I called the Adventure by signal under 
my stern ; which was no sooner done, than the haze increased 
so much, with snow and sleet, that we did not see an island of 
ice, which we were steering directly for, till we were less than 
amile from it. I judged it to be about fifty feet high, and 
half a mile in circuit. It was flat at the top, and its sides rose 
in a perpendicular direction, against which the sea broke ex- 
ceedingly high... . 

At one o’clock we steered for an island of ice, thinking, if 
there were any loose ice round it, to take some on board, and 
convert it into fresh water. At four we brought to, close un- 
der the lee of the island; where we did not find what we 
wanted, but saw upon it eighty-six penguins. This piece of 
ice was about half a mile in circuit and one hundred feet high 
and upward, for we lay for some minutes with every sail be- 
calmed under it... . 

At nine in the morning we bore down to an island of ice 
which we reached by noon. It was full half a mile in circuit, 
and two hundred feet high at least, though very little loose ice 
about it. But while we were considering whether or not we 
should hoist out our boats to take some up, a great quantity 
broke from the island. Upon this we hoisted out our boats, 
and went to work to get some on board. ‘The pieces of ice, 
both great and small, which broke from the island, I observed, 
drifted fast to the westward ; that is, they left the island in 
that direction, and were, in a few hours, spread over a large 
space of sea... . 

Finding here a good quantity of loose ice, I ordered two 
boats out, and sent them to take some on board. While this 


116 THE ICH AGH IN NORTH AMERICA. 


was doing, the island, which was not less than half a mile in 
circuit, and three or four hundred feet high above the surface 


Fig. 38.—Iceberg. 


of the sea, turned nearly bottom up. Its height, by this 
circumstance, was neither increased nor diminished appar- 
ently.7 

In the evening we had three islands of ice in sight, all of 
them large ; especially one, which was larger than any we had 
yet seen. The side opposed to us seemed to be a mile in ex- 
tent ; if so, it could not be less than three in circuit. As we 
passed it in the night, a continual cracking was heard, occa- 
sioned, no doubt, by pieces breaking from it. For, on the 
morning of the 6th, the sea, for some distance round it, was 
covered with large and small picces ; and the island itself did 
not appear so large as it had done the evening before. It 
could not be less than one hundred feet high; yet such was 
the impetuous force and height of the waves which were 
broken against it, by meeting with such a sudden resistance, 
that they rose considerably higher.* 


For a series of years the Board of Trade in England col- 
lected statistics from the navigators of the Southern Ocean 
who reported icebergs encountered in their voyages. From 


* “ Voyage round the World,” pp. 20, 29, 48-50, 54. 


S-, J 
4 


GLACIERS IN OTHER PARTS OF THE WORLD. 117 


these reports, and from a paper of Mr. Towson upon the 
subject, published by the Board of Trade, Mr. Croll makes 
the following collection of facts concerning them, premising 
that, “‘ with one or two exceptions, the heights of the bergs 
were accurately determined by angular measurement ” : 


September 10, 1856.—The Lightning when in latitude 55° 
33’ south, longitude 140° west, met with an iceberg 420 feet 
high. 

November, 1839.—In latitude 41° south, longitude 87° 30’ 
east, numerous icebergs 400 feet high were met with. 

September, 1840.—In latitude 37° south, longitude 15° 
east, an iceberg 1,000 feet long and 400 feet high was met 
with. : 

February, 1860.—Captain Clark, of the Lightning, when 
in latitude 55° 20’ south, longitude 122° 45’ west, found an 
iceberg 500 feet high and three miles long. 

December 1, 1859.—An iceberg, 580 feet high, and from 
two and a half to three miles long, was seen by Captain Smith- 
ers, of the Edmond, in latitude 50° 52’ south, longitude 43° 58’ 
west. So strongly did this iceberg resemble land that Captain 
Smithers believed it to be an island, and reported it as such, 
but there is little or no doubt that it was in reality an iceberg. 
There were pieces of drift-ice under its lee. 

November, 1856.—Three large icebergs, 500 feet high, 
were found in latitude 41° 0’ south, longitude 42° 0’ east. 

January, 1861.—Five icebergs, one 500 feet high, were met 
with in latitude 55° 46’ south, longitude 155° 56’ west. 

January, 1861.—In latitude 56° 10’ south, longitude 160° 
0’ west, an iceberg 500 feet high and half a mile long was 
found. ; 

January, 1867.—The bark Scout, from the west coast of 
America, on her way to Liverpool, passed some icebergs 600 feet 
in height and of great length. 

April, 1864.—The Royal Standard came in collision with 
an iceberg 600 feet in height. 

December, 1856.—Four large icebergs, one of them 700 
feet high, and another 500 feet, were met with in latitude 50° 
14’ south, longitude 42° 54’ east. 


118 THE ICE AGE IN NORTH AMERICA. 


December 25, 1861.—The Queen of Nations fell in with an 
iceberg in latitude 53° 45’ south, longitude 170° 0’ west, 720 
feet high. 

December, 1856.—Captain P. Wakem, ship Ellen Radford, 
found, in latitude 52° 31’ south, longitude 43° 43’ west, two 
large icebergs, one at least 800 feet high. 

Mr. Towson states that one of our most celebrated and 
talented naval surveyors informed him that he had seen ice- 
bergs in the southern regions 800 feet high. 

March 23, 1855.—The Agneta passed an iceberg in latitude 
53° 14’ south, longitude 14° 41’ east, 960 feet in height. 

August 16, 1840.—The Dutch ship, General Baron von 
Geen, passed an iceberg 1,000 feet high in latitude 37° 32’ south, 
longitude 14° 10’ east. 

May 15, 1859.—The Basen found, in latitude 53° 40’ 
south, longitude 123° 17’ west, an iceberg as large as ‘‘ Tristan 
d’ Acunha.” * 


Upon these facts Mr. Croll remarks : 


In the regions where most of these icebergs were met with, 
the mean density of the sea is about 170256. The density of 
ice is ‘92. The density of icebergs to that of the sea is there- 
fore as 1 to 1°115 ; consequently, every foot of ice above water 
indicates 8°7 feet below water. It therefore follows that those 
icebergs 400 feet high had 3,480 feet under water—3,880 feet 
would consequently be the total thickness of the ice. The 
icebergs which were 500 feet high would be 4,850 feet thick, 
those 600 feet high would have a total thickness of 5,820 feet, 
and those 700 feet high would be no less than 6,790 feet thick, 
which is more than a mile and a quarter. The iceberg 960 
feet high, sighted by the Agneta, would be actually 9,312 feet 
thick, which is upward of a mile and three quarters. © 

Although the mass of an iceberg below water compared to 
that above may be taken to be about 8°7 to 1, yet it would not 
be always safe to conclude that the thickness of the ice be- 
low water bears the same proportion to its height above. If 
the berg, for example, be much broader at its base than at its 


* “ Climate and Time,” pp. 382-385. 


A 


a a+ 
dd 


sees 


a ae 


j 
j 


GLACIERS IN OTHER PARTS OF THE WORLD, 119 


top, the thickness of the ice below water would bear a less pro- 
portion to the height above water than as 8-7 to 1. But a berg, 
such as that recorded by Captain Clark, 500 feet high and three 
miles long, must have had only 1 to 8°7 of its total thickness 


Fie. 39.—Floating berg, showing the proportions above and under the water. 


above water. ‘The same remark applies also to the one seen by 
Captain Smithers, which was 580 feet high, and so large that it 
was taken for an island. This berg must have been 5,628 feet 
in thickness. ‘The enormous berg which came in collision with 
the Royal Standard must have been 5,820 feet thick. It is not 
stated what length the icebergs 730, 960, and 1,000 feet high 
respectively were; but supposing that we make considerable 
allowance for the possibility that the proportionate thickness 
of ice below water to that above may have been less than as 8°7 
to 1, still we can hardly avoid the conclusion that the icebergs 
were considerably above a mile in thickness. But if there are 
icebergs above a mile in thickness, then there must be land-ice 
somewhere on the southern hemisphere of that thickness. In 
short, the great antarctic ice-cap must in some places be over a 
mile in thickness at its edge. 


120 THE ICE AGE IN NORTH AMERICA. 


Interest in Antarctic exploration did not revive until the 
beginning of the present century, but since then it has been 
very active. In 1901 Captain Scott of the English navy set 
out in the vessel Discovery and, during the following year, 
reached a point within 670 miles of the south pole, 100 miles 
nearer than anyone had been before. 

On August 7, 1907, Lieut. Ernest Shackelton, of the Eng- 
lish navy sailed from Plymouth for the purpose of reaching 
the south pole. On January 6, 1909, his party reached a 
point within ninety-three geographical miles of the pole and 
then was compelled to turn back. Here they were on a plateau 
between 10,000 and 11,000 feet above sea-level, which seemed 


to stretch unbroken southward as far as their glass could — 


extend their vision, thus revealing conditions very different 
_ from those about the north pole, where there is a sea several 
thousand feet deep covered with drifting ice. — 

According to Lieutenant Shackelton, ‘‘We now know that 
the Great Southern Ice Barrier is bounded by mountains 
running in a southeasterly direction from 78° south at least, 
and that an immense glacier leads to a plateau over 10,000 
feet above the sea level, on which is situated the geographical 
south pole. 

“Numerous inland mountains have been discovered, and 
specimens of rock from them show that at some period in 
the geological history of the earth a warm climate prevailed 
in these ice bound regions.” 

“The discovery of microscopical life in the frozen lakes is 
extremely interesting. Thescientists of the expedition demon- 
strated that the tiny rotifers could exist in a temperature of 
100° of frost, and also emerge unscathed from the test of a 
temperatureof200°F. . . . . Strange asit may seem, 
there is a large marine fauna in the icy waters of the Antarctic. 
The temperature of the sea in those regions varies but little 
in winter and summer, and this fact is conducive to an abun- 
dant marine life.” 


_— — 


GLACIERS IN OTHER PARTS OF THE WORLD 121 


Among the most important discoveries was that of the . 
South Magnetic Pole. Leaving their winter quarters on Octo- 
ber 5th, they traveled westward amid great difficulties and 
dangers 250 miles along the coast on the sea ice, “‘relaying”’ 
the whole distance. As the summer advanced they began to 
suffer from the heat, and although they were traveling over 
ice they often had to divest themselves of their outer gar- 
ments. On the 16th of December they left the shore and 
struck inland in the direction of the Magnetic Pole, which 
they estimated to be about 200 miles distant. During this 
journey they encountered, though in the midst of summer, a 
heavy snowfall and a succession of blizzards. extending 
through a fortnight. They also, like the southern party 
had to ascend a high plateau and found the ice covering to 
be a perfect maze of crevasses, which rendered travel almost 
impossible. Following the magnetic meridian, and ascend- 
ing a succession of terraces, they at length reached an undulat- 
ing snow plain 7,000 or 8,000 feet above sea-level, where the 
traveling was easier, and on the 16th of January reached the 
object of their search in latitude 72° 45’ south, longitude 
145.° Here they hoisted the Union Jack and claimed the 
land in the name of his Majesty the King of England. The 
cold at this elevation was intense, and there was a continual 
ice wind from the southwest, with a succession of blizzards. 
Hoisting a sail and thus taking advantage of this wind the 
party reached their depot on the 3d of February in a state of 
semi-starvation. 


CHAPTER VI. 
SIGNS OF FORMER GLACIATION. . 


BrrorE attempting to delineate the exact southern 
boundary of the ice during the height of the Glacial period 
in North America, it will be necessary briefly to discuss the 
evidence upon which the inferences concerning the Glacial 
period are based. The reader will ask: How is it possible 
to determine, with any reasonable degree of accuracy, the 
sxtent of the region formerly covered by glacial ice, but 
which has been. free from such covering for many thousand 
years, and during all that time has been subjected to the 
disintegrating and modifying influences connected with the 
ceaseless operation of the ordinary forces of Nature ? 

The consideration of this question will imtroduce us not 
only to some of the most interesting problems of this par- 
ticular subject, but to some of the fundamental principles 
underlving all inductive reasoning. The study of the great 
Ice age, like all other branches of geology, deals with the 
effects of past causes. From the marks which have been 
left upon the surface of the earth, we endeavor by scientific 
processes to reproduce to our imagination the condition of 
things which would account for these marks. As reasonable 
beings, we are compelled to bring into the field of thought 
a past cause sufficient to produce all the results observed, 
both positive and negative; and when our imagination has 
found an adequate cause, true science compels us to rest with 
that. 

From observation upon living glaciers, and from the 
known nature of ice, we may learn to recognize the track 


SIGNS OF FORMER GLACIATION. 123 


of a glacier as readily and unmistakably as we would the 
familiar foot-prints of an animal. The indications upon which 
glacialists have depended for their information as to the ex- 
tent of the glaciated region during the great Ice age are of 
three kinds: 1. Grooves and scratches preserved upon the 
rocks in place and upon the bowlders and pebbles shoved 
along under the ice. 2. The extensive unstratified deposits 
ealled “ till,” which are traceable to glacial action. 38. Trans- 
ported material found in such positions that it must have 
been left by glacial ice rather than floating ice. 

In respect of the nature of ice we are compelled to ad- 
mit that it is capable of motion like such semi-fluids as cool- 


Fie. 40.—Scratched stone from the till of Boston. Natural size about one foot and a half 
long by ten inches wide. (From photograph.) 


ing pitch or lava. But, though it does move, it is not capa- 
ble of adapting itself so perfectly as a real fluid to the 


Sn ei ta eR WS 


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Aq yjiou Ajivou vuole ‘ay eyYeT Jo YINOS sali aAg ‘OIYO “JIoYUY ‘aUOJSspUBS volOg UO SYIVUL ABUNT-IdIes pUue BITS [VIOVLO— TP ‘Oly 


SIGNS OF FORMER GLACIATION. 125 


inequalities of the country. From this comparatively solid 
character of ice certain important results must follow. It 
is easy to see that the stones of all sizes, while being dragged 
along underneath the ice, would be held in a comparatively 
firm grasp so as to be polished and striated and scratched in 
a peculiar manner. On the shores of bays and lakes and in 
bottoms of streams we find that the stones are polished and 
rounded in a symmetrical manner, but are never scratched. 
The mobility of water is such that the edges and corners of 
the stones are rubbed together by a force acting successively 
in every possible direction. But in and under the ice the 
firm grasp of the stiff semi-fluid causes the stony fragments 
to move in a nearly uniform direction, so that they grate 
over the underlying rocks like a rasp, wearing down the 
rocks beneath and slowly grinding them to powder, and, 
at the same time, being worn themselves in the process. 
From the stability of the motion of such a substance as ice 
there would, from the nature of the case. result groovings 
and striation both on the rocks beneath and on the bowlders 
and pebbles which, like iron plowshares, are forced over 
them. Scratched surfaces of rock and scratched stones are 
therefore, in ordinary cases, most trustworthy indications of 
glacial action. The direction of the scratches upon these 
glaciated bowlders and pebbles is, also, worthy of notice. 
The scratches upon the loose pebbles are mainly in the direc- 
tion of their longest diameter—a result which follows from 
a mechanical principle, that bodies forced to move through 
a resisting medium must swing around so as to proceed in 
the line of least resistance. Hence the longest diameter of 
such moving bodies will tend to come in line with the direc- 
tion of the motion. 

A scratched surface is, however, not an infallible proof 
of the former presence of a glacier where such a surface is 
found, or, indeed, of glacial action at all. A stone scratched 
by glacial forces may float away upon an iceberg, and be 
deposited at a great distance from its home. Indeed, ice- 
bergs and shore-ice may produce, in limited degree, the phe- 


126 THE ICE AGH IN NORTH AMERICA. 


nomena of striation which we have just described. One ean 
but admire the enthusiasm with which the old defenders of 
the iceberg theory dwelt upon the capacity of icebergs and 
shore-ice to polish, groove, and scratch the surfaces over 
which they moved. Sir Charles Lyell tells us, in the ac- 
count of his first visit to America, how he stood at the foot 
of a cliff at Cape Blomidon, Nova Scotia, transfixed at the 
sight of recent furrows which were the exact counterpart of 
the grooves of ancient date which he had elsewhere described. 
So extensive were these, that they seemed for the moment 
to render the glacial theory unnecessary : 


As I was strolling along the beach at the base of these ba- 
saltic cliffs, collecting minerals, and occasionally recent shells 
at low tide, I stopped short at the sight of an unexpected phe- 
nomenon. The solitary inhabitant of a desert island could 
scarcely have been more startled by a human foot-print in the 
sand, than I was on beholding some recent furrows on a ledge 
of sandstone under my feet, the exact counterpart of those 
grooves of ancient date which I have so often described in this 
work, and attributed to glacial action. After having searched 
in vain at Quebec for such indications of a modern date, I had 
despaired of witnessing any in this part of the world. I was 
now satisfied that, whatever might be their origin, those before 
me were quite recent. 

The inferior beds of soft sandstone which are exposed at 
low water at the base of the cliff at Cape Blomidon, form a 
broad ledge of bare rock, to the surface of which no sea-weed 
or barnacles can attach themselves, as the stone is always wear- 
ing away slowly by the continual passage of sand and gravel, 
washed over it from the talus of fallen fragments which lies at 
the foot of the cliff on the beach above. The slow but con- 
stant undermining of the perpendicular cliff forming this 
promontory, round which the powerful currents caused by the 
tide sweep backward and forward with prodigious velocity, 
must satisfy every geologist that the denudation by which the 
ledge in question has been exposed to view is of modern date. 
Whether the rocks forming the cliff extended so far as the 
water’s edge, ten, fifty, or one hundred years ago, I have no 


SIGNS OF FORMER GLACIATION. 127 


means of estimating; but the exact date and rate of destruc- 
tion are‘immaterial. On this recently-formed ledge I saw sev- 
eral straight furrows half an inch broad, some of them very 
nearly parallel, others diverging, the direction of the former 
being north 35° east, or corresponding to that of the shore at 
this pomt. After walking about a quarter of a mile, I found 
another set of similar furrows, having the same general direc- 
tion within five degrees ; and I made up my mind that, if these 
grooves could not be referred to the modern instrumentality of 
ice, it would throw no small doubt on the glacial hypothesis. 
When I asked my guide—a peasant of the neighborhood— 
whether he had ever seen much ice on the spot where we stood, 
the heat was so excessive (for we were in the latitude of the 
south of France, 45° north), that I seemed to be putting a 
strange question. He replied that, in the preceding winter of 
1841, he had seen the ice, in spite of the tide, which ran at the 
rate of ten miles an hour, extending in one uninterrupted mass 
from the shore where we stood to the opposite coast at Parrs- 
borough, and that the icy blocks, heaped on each other, and 
frozen together or ‘‘ packed” at the foot of Cape Blomidon, 
were often fifteen feet thick, and were pushed along, when the 
tide rose, over the sandstone ledges. He also stated that frag- 
ments of the ‘‘ black stone ” which fell from the summit of the 
cliff, a pile of which lay at its base, were often frozen into the 
ice, and moved along with it. I then examined these fallen 
blocks of amygdaloid scattered around me, and observed in 
them numerous geodes coated with quartz-crystals. I have 
no doubt that the hardness of these gravers, firmly fixed in 
masses of ice, which, although only fifteen feet thick, are often 
of considerable horizontal extent, have furnished sufficient 
pressure and mechanical power to groove the ledge of soft 
sandstone. * 


Stones are also striated by other agencies than moving ice. 
Extensive avalanches and land-slides furnish conditions analo- 
gous to those of a glacier, and might in limited and favor- 
able localities simulate its results. In those larger geological 


* “Travels in America,” first series, vol. ii, pp. 144-146. 


; (PSM Aq AvAING [BdIsO[ONH) 807819 poylUQ ayy Jo ydvasojoyd vB UIOI) ‘GdN0I} JUOSeId 871 papots BONIS SRY yaold euL ‘esVv 
G0] BY} JO VSO[O OY} 4B [BII9}VU poy!}vA]s OY} pozlsodep spooy [BIOB[d oy, ‘“S9U0js poayoywsos Jo [[NJ pus payljvajsun st yoos AJUOMY JOMOT OUT, 
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SIGNS OF FORMER GLACIATION. 129 


movements, also, where the crust of the earth is broken and 
the edges of successive strata are shoved over each other, a 
species of striation is produced which in technical terms is 
ealled a slickenside. Occasionally this deceives the inex- 
perienced or incautious observer. But by due pains all these 
semblances may be detected and eliminated from the prob- 
lem, leaving a sufficient number of unquestionable phenom- 
ena due to true glacial action. 

A second indubitable mark of glacial action is found in 
the character of the deposit left after the retreat of the ice. 
Ice and water differ so much from each other in the extent of 
their fluidity, that ordinarily there is little danger of confus- 
ing the deposits made by them. A simple water deposit is 
inevitably stratitied. The coarse and fine material can not be 
deposited by water alone, simultaneously in the same place. 
Along the shores of large bodies of water the deposits of 
solid material are arranged in successive parallel lines, the 
material growing finer and finer as the lines recede from the 
shore. The force of the waves is such in shallow water that 
they move pebbles of considerable size. Indeed, where the 
waves strike against the shore itself, vast masses of rock are 
oftentimes moved by the surf. But, as deeper water is 
reached, the force of the waves becomes less and less at the 
bottom, and so the transported material is correspondingly 
fine, until, at the depth of about seventy feet, the force of 
the waves is entirely lost; and beyond that line nothing will 
be deposited but fine mud, the particles of which are for a 
long while held in suspension before they settle. 

In the deltas of rivers, also, the sifting power of water 
may be observed. Where a mountain-stream first debouches 
upon a plain, the force of its current is such as to move large 
pebbles, or bowlders even, two or three feet in diameter. 
But, as the current is checked, the particles moved by it be- 
come smaller and smaller until in the head of the bay, or in 
the broad current of the river which it enters, only the finest 
sediment is transported. The difference between the size otf 
material transported by the same stream when in flood and 


130 THE ICE AGH IN NORTH AMERICA. 


when at low water is very great, and is the main agent in pro- 
ducing the familiar phenomena of stratification. During the 
time of a flood vast bodies of pebbles, gravel, and sand are 
pushed out by the torrent over the head of the bay or delta 
into which it pours; while during the lower stages of water 
only fine material is transported to the same distance; and 
this is deposited as a thin film over the previous coarse deposit. 
Upon the repetition of the flood another layer of coarser 
material is spread over the surface; and so, in successive 
stages, is built up in all the deltas of our great rivers a series 
of stratified deposits. In ordinary circumstances it is impos- 
sible that coarse and tine material should be intermingled in 
a water deposit without stratification. Water moving with 
various degrees of velocity is the most pertect sieve imagi- 
-nable ; so that a water deposit is of necessity stratified. 

To this general principle, however, exception must be 
made in the case of accumulations taking place slowly in 
deep water containing icebergs from which bowlders and 
pebbies may be dropped. These, of course, will be found 
distributed through the fine deposit without stratification. 
It is thought by President Chamberlin,* however, that in 
cases where the bowlders dropped from the icebergs are of 
marked irregularity in their configuration, their position in 
the ooze at the bottom would betray their origin. Flattish 
stones, in falling through the water, would often descend 
edgewise, and would not uniformly le in the mud upon 
their flat surface. I have myself observed numerous places 
in southern Ohio where the arrangement of the limestone 
fragments abundantly illustrates and confirms this theory. 
The horizontal position of such fragments in the clay of that 
region seems to show that they were arranged in the deposit 
by a moving ice-sheet, and were not dropped from floating ice. 

It is evident that ice is so nearly a solid that the earthy 
material deposited by it must be unassorted. The mud, sand, 
gravel, pebbles, and bowlders, dragged along underneath a 


* “Terminal Moraine of the Second Glacial Epoch,” p. 297. 


(ys Aq AOAING [BOLSO[OOH so7RIG pony oyy jo ydvasojoyd B WoL) “Jos U9AIJY JLOGR IYSIoFT *(7Xeq Vas) ouUOJSoUTIT JO 
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132 THE ICE AGE IN NORTH AMERICA. 


moving stream of ice, must be left in an unstratified eondi- 
tion—the coarse and the fine being indiscriminately mingled 
together. Now, this is the character of the extensive deposits 
of loose material which cover what we designate as the gla- 
ciated region. It is true that over this region there are exten- 
sive stratified deposits. But these invariably mark the situa- 
tion of abandoned lakes and water-courses. ‘To these interest- 
ing formations a special chapter will be devoted. But the 
larger part of the region marked upon the map as glaciated 
is covered with an unstratified deposit, in which are mingled 
a variety of materials derived from rocks both of the locality 
and of far-distant regions. Moreover, the pebbles in this de- 
posit are the most of them polished and scratched after the 
manner of those which we know to have been subjected to 
glacial action. Ordinarily there can be no question of the 
glacial character of this formation, even when no considera- 
tions are taken into account except those which appear in the 
deposit itself. Still, in certain situations, floating ice may 
transport coarse material, and drop it in the midst of finer 
silt, so as closely to simulate a true unstratified deposit. In 
the majority of cases, however, the configuration of the coun- 
try is such as to exclude the agency of floating ice from the 
problem. 

We come, therefore, in the third place, to a mass of 
recently discovered facts which would seem to place the 
glacial theory above all question. When once the limit of 
these unstratified deposits, containing striated stones and 
transported material, had been accurately determined, it was 
found that the margin was exceedingly irregular in two re- 
spects. The southern edge of this deposit is both serrate 
and erenate-—that is, it does not follow a straight east-and- 
west line, but in places withdraws to the north, and in others 
extends in lobe-shaped projections far to the south. This 
constitutes its serrate character. But it is the crenate char- 
acter of its southern border which is of most significance. 
The southern border, with its indentations and projections, 
is not determined by any natural barrier. The southern 


—~ 


SIGNS OF FORMER GLACIATION. 133 


boundary-line rises from the level of the sea at New York 
to the height of the Blue Mountains in New Jersey, and 
descends into the valley of the Delaware, and rises again 
over the Blue Ridge in Pennsylvania, crossing the valley 
between it and Pocono Mountain, where it runs for many 
miles at an elevation of 2.000 feet above the sea, and descends 
in a nearly straight line to the East Branch of the Susque- 
hanna at Beach Haven, where it is not more than 500 feet 
above the sea. ‘thence it continues onward in a diagonal 
course across the Alleghanies, with their various subsidiary 
valleys, to its great turning-point in southwestern New York. 
Thence to the trough of the Mississippi, for a distance of 
700 or 800 miles, the line winds gradually down the west- 
ern flanks of the Alleghanies, paying little attention in its 
deflections to the minor inequalities of the country. West 
of the Mississippi the rise is equally gradual to northern 
Dakota and Montana, where the glacial border is 2,000 or 
3,0U0, and in British America 4,000, feet above the sea. 

Thus it is not possible, by the supposition of any conceiv- 
able submergence, to account for this line of cemarkation. 
Water which would have floated ice from the north to almost 
any point along that line would have floated it farther south. 
Consequently, the line must have been determined not by a 
barrier which restrained a fluid, but by the irregular losses 
of momentum such as would take place in a semi-fluid mov- 
ing in the line of least resistance from various central points 
of accumulation. 

The reader will find the subject of this chapter treated 
with great fullness by President Chamberlin in the “ Third 
Annual Report of the United States Geological Survey,” pp. 
291-402, and in the “Seventh Report,” pp. 149-248, where 
the snbject of rock-scoring is most fully illustrated. Numer- 
ous illustrations in the present volume have been reserved for 
the latter part of Chapter X, on “ Glacial Erosion and Trans- 
portation,” which the .reader will do well to consult in this 
connection as well as in the order in which it occurs. 


CHAPTER VIL. 
BOUNDARY OF THE GLACIATED AREA IN NORTH AMERICA. 


Dousrirss the Ice age both began and ended in a great 
number of local glaciers which became confluent and con- 
tinuous only during the middle of the period. One of the 
most interesting evidences of the independent movement of 
the different portions of the great North American ice-sheet 
is to be found in the driftless region of southwestern Wis- 
consin. Here is an area of several hundred square miles in 
extent, occupying more or less of the adjoining area in I]h- 
nois, Lowa, and Minnesota, which remained as an island in 
the great continental expanse of ice. The ice moved past it 
upon both sides, and then closed together upon the south, 
and moved onward, a distance of about 300 miles, to the 
vicinity of St. Louis. 

When, in the year 1876, attention was first directed by 
Mr. Clarence King,* Mr. Warren Upham,t and Professor 
George H. Cook ¢ to the terminal moraines of southern New 
England and northern New Jersey, by President T. C. Cham- 
berlin* to the character and connection of the kettle-mo- 
raine in Wisconsin, and by Dr. George M. Dawson | to the 


* See my paper in the “Proceedings of the Boston Society of Natural His- 
tory,” vol. xix, pp. 60-63. 

+ ““New Hampshire Geological Report,” vol. iii, pp. 300-305. 

t “Report upon the Geology of N ew Jersey for 1878.” 

# “On the Extent and Significance of the Wisconsin Kettle-Moraine.” 

|| “On the Superficial Geology of the Central Region of North America,” 
from the “ Quarterly Journal of the Geological Society,” vol. xxxi, 1875. This 
is a summary of a portion of the author’s “Report on the Geology and Re- 
sources of the Forty-ninth Parallel,’”’ 1875. 


BOUNDARY OF THE GLACIATED AREA. 135 


significance of the extension of the Missouri coteau in Brit- 
ish America, hopes were at once raised that a distinct line 
of terminal moraines might be traced across the continent. 
With this theory in mind, the late Professor H. Carvill 
Lewis and myself began the survey of Pennsylvania in 1881. 
But, upon crossing the Alleghanies and pursuing the investi- 
gations in the Mississippi Valley, 1 was compelled to aban- 
don this view, and to be content with finding marginal de- 
posits more evenly spread over the country, ending, in some 
cases, in an extremely attenuated border. And, upon reflec- 
tion, the fallacy in our original theory, that there must be a 
terminal moraime—that is, a noticeable ridge of glacial ac- 
cumulations to mark the farthest extent of the ice—is easily 
seen. } 

The extent of a glacial deposit at any particular point 
will be determined by three factors, namely: 1. The amount 
of accessible loose material in the line of glacial movement 
which the ice can seize upon and transport. It is evident 
that, if the rocks over which the ice moves are hard and 
smooth and already denuded of loose material, there may 
be much motion of ice with little transportation of soil. 
2. The length of time during which the ice-front remains 
at a given point, since time acts as a multiplier. 3. The 
exemption of the deposit from the action of denuding agen- 
cies. When a glacier melts, the torrents of water arising 
may, in a short time, tear down and distribute as sediment 
to distant valleys the material accumulated by the slow 
movement of centuries. Indeed, it has been questioned by 
some whether the larger part of the grist of the glacier has 
not been thus transported far beyond the extreme limits 
reached by the ice itself. This transportation by water from 
the front of glaciers is certainly of immense extent. Every 
subglacial stream is surcharged and milky-white with sedi- 
ment as it emerges from the ice-front. As before stated, a 
traveler in the State of Washington, from Portland to 
Seattle, can detect the presence of glaciers in the Cascade 
Mountains, scores of miles away, simply by the milky color of 


136 THE ICH AGE IN NORTH AMERICA. 


the streams crossed by the railroad. At Tacoma, on Puget 
_ Sound, the milk-white water, coming down from distant gla- 
ciers in Mount Tacoma, struggles with the dark-blue water 
of the sound for the occupancy of the harbor, and gives the 
surface of the bay the nondescript appearance of an im- 
mense slice of marble-cake. As one passes the mouth of 
the Stickeen River beyond Fort Wrangel, in Alaska, the 
line of demarkation between the clear waters of the ocean 
and those of the glacier-laden currents of the river is as plain 
as that between the water itself and the shore. One of the 
most interesting occupations of the leisure hours of our long 
encampment in Glacier Bay was to watch this struggle for 
occupancy between the milk-white water of the four sub- 
glacial streams pouring into the inlet, and the pure blue 
waves urged against it by the recurring tides of the ocean. 
With arising tide of twenty-two feet, the line of demarka- 
tion between the glacial water and the waters from the Pacific 
moved alternately backward and forward over the inlet for a 
distance of one or two miles, and in the shallow water, miles 
away, the screw of the steamer brought to the surface great 
quantities of the sediment which is rapidly filling up the bay. 

“When one considers the constancy of the operation of 
this cause during all glacial time, he may well be pardoned ~ 
for regarding the glacial débris still remaining upon the con- 
tinent as but an insignificant remnant of the total amount 
transported and deposited by glaciai action. During the 
whole continuance of the Glacial period in North America, — 
subglacial streams must have sent their turbid currents down 
through every New England outlet, and through the Hud- 
son, the Delaware, the Susquehanna, and all the northern 
tributaries of the Mississippi. The terraces marking these 
glacial water-courses retain simply a part of the coarser ma- 
terial transported ; the fine material went constantly onward 
to the sea, helping to build up the immense delta of the lower 
Mississippi, and to line the whole coast of the Atlantic with 
a deposit of fine sediment ready at some day to rise above 
the surface as fruitful soil. 


BOUNDARY OF THE GLACIATED AREA. 137 


With these remarks, we are prepared to come to the spe- 
cific subject of the present chapter, namely, the character 
and extent of the glacial deposits marking the southern bor- 
der of the glaciated area in North America. Through a por- 
tion of the distance these accumulations are so marked as to 
merit the name of terminal moraines. Through another 
portion that name is hardly applicable to anything near the 
glacial border. In a subsequent chapter there will be a dis- 
tinct discussion of the whole question of moraines. In this 
it is our purpose to follow somewhat minutely the boundary 
of the area, and detail its various aspects. 

Off the coast of Maine the ice, at its culminating period, 
extended an unknown distance into the sea, surmounting the 
eminences of Mount Desert and all that rock-bound coast, and 
leaving its terminal deposits in water so deep that there is 
little hope of ever determining its exact situation. But in 
southeastern Massachusetts the deposits emerge from the 
water as true moraines, and offer themselves as most interest- 
ing objects of study. Nantucket, Tuckernuck, Chappaquid- 
dick, Martha’s Vineyard, No Man’s Land, and Block Island 
are but portions of the extreme terminal moraine whose back 
emerges at these points from the water. Cape Cod, from 
Provincetown to Wood’s Holl and the Elizabeth Islands, is a 
similar remnant of a vast moraine formed after the ice-front 
had withdrawn a short distance to the north. Indeed, the 
whole of Plymouth and Barnstable counties is “ made land,” 
as really as that of the Back Bay in Boston, only in the one 
ease the earth was dumped, day by day, from the laborer’s 
cart, and in the other year by year, from the melting front 
of the continental ice-sheet. 

It is an instance of misleading poetic license which per- 
mits us to sing of the “rock-bound” shore upon which the 
Pilgrim Fathers landed, for there are no rock-bound shores 
in southeastern Massachusetts. The hills which first greeted 
the eyes of the Pilgrim Fathers are the irregular morainic 
accumulations so frequently characteristic of glacial margins. 
In this case the soil composing them consists of sand, gravel, 


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BOUNDARY OF THE GLACIATED AREA. 139 


and bowlders which have been scraped off by the ice from 
the mountains and ledges of New Hampshire and the inter- 
vening portions of Massachusetts, transported to the glacial 
margin, and there deposited in such quantities as to consti- 
tute the whole southeastern portion of the latter State. The 
three hundred and sixty lakes of Plymouth township are 
nothing else than a cluster of kettle-holes. Manomet Hill, 
southeast of Plymouth, is not a mountain which has been 
thrust up by convulsive agencies, nor yet a remnant of a par- 
tially eroded plateau, but a glacial deposit, hundreds of feet 
in height and many miles in extent. From the fact of its 
running nearly at right angles to the backbone of Cape Cod, 
Manomet Hill is spoken of by some as a medial moraine. 
But it is doubtful if it is necessary so to regard it. The re- 
treat of a glacier, like the retreat of an army, is determined 
in part by the nature of the opposing foe. In the present 
instance there are abundant reasons for believing that the ice 
retreated by the left flank; for it is evident that the ocean 
had much to do in setting bounds to the general southeastern 
movement of the ice-sheet in New England. From the con- 
tour of the coast, it can be seen at a glance that the waters of 
the ocean had constant opportunity to eat in upon the ice 
from the east as well as from the south. 

Nantucket marks the extreme southeastern limit. Here 
the ice maintained its position against opposing forces, until 
the outer line of moraines just mentioned was built up. The 
next line of defense taken up by the ice is that marked by 
the backbone of Cape Cod. The retreat had been farthest 
on the side most exposed to the ocean, and hence the dis- 
tance between the moraine of Nantucket and that at South 
Brewster is much greater than the distance between Martha’s 
Vineyard and Wood’s Holl. The next line of defense taken 
up by the ice-front along the course of Manomet Hill, left 
Cape Cod and the whole shore of eastern Massachusetts open 
to the undisputed sway of the ocean. 

The two lines of moraine so clearly marked in south- 
eastern Massachusetts can be readily traced westward through 


140 THE ICE AGE IN NORTH AMERICA. 


a considerable portion of Long Island. The exterior line, 
beginning at Montauk Point, forms the backbone of the 
island as far as Brooklyn, N. Y., the city itself being built 
upon it. The interior or parallel line, represented to the 
east by the backbone of Cape Cod and the Elizabeth Islands, 
disappears beneath the deeper waters of Buzzard’s Bay, to 
emerge upon the mainland at Point Judith in Rhode Island, 
and give variety to the whole coast of the State westward 
from that point. This part of the moraine presents many 
features of special interest at Watch Hill, Fisher’s and Plum 
Islands, and on the northern shore of Long Island as far as 
Port Jefferson. Westward from Port Jefferson only the 
external line of moraine hills is traceable, Staten Island in 
New York Harbor being a most interesting development of 
it. The northern and western portions of this island are 
covered with the peculiar combination of rounded knobs and 
circular depressions characteristic of moraines, while the 
southeastern portion of the island was just beyond the reach 
of the ice, and the deposits upon it are of an entirely differ- 
ent character. 

Up to this point in our investigations some dount may 
attach to the inferences concerning the limits of the great 
ice-sheet. or, since the ocean everywhere expands to the 
south, it may be asked, What certainty is there that its 
waters do not cover a belt of glacial deposits still farther out 
than those now visible? No positive answer can be made to 
this objection. But, on striking the coast of New Jersey 
opposite Staten Island, a fair field of investigation is at once 
offered, and doubt as to the substantial correctness of the 
delineation farther on need be no longer entertained. The 
line of moraine hills across New Jersey is a direct continua- 
tion of thcse forming the backbone of Long Island, and 
covering the northern half of Staten Island. Here they 
form a sharp line of demarkation between the glaciated 
region to the north and the unglaciated plains to the south. 
Beginning at Perth Amboy, the moraine bends northward 
through Raritan, Plainfield, Chatham, Morris, and Hanover, 


7 ok 


are 


= 
> 
4 
= 
= 
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ee 
1 20 30 


j 0 0 


Struthers ¢ Co., Engr’s, N.Y. 


But the ‘‘Attenuated Border”’ 


Fic. 45.—The moraine according to Lewis and Wright. 
extended below the mouth of the Lehigh. See Chapter VII, Continued. 


142 THE ICE AGE IN NORTH AMERICA. 


to Rockaway, thence a little south of west to Belvidere on 
the Delaware, a few miles above Easton. The innumerable 
throngs of passengers between New York and Philadelphia 
can not, after their attention has been once ealled to the 
facts, fail to notice this moraine as the southward-bound 
trains pass through it, and emerge into a level, sandy region 
free from bowlders and all irregular drift deposits. At Me- 
tuchen and at Plainfield the transition is almost as clearly 
marked as that between land and water. 

Before following the terminal belt farther west, where 
its characteristics are more or less disguised by the local 
topography, we will pause to consider more carefully some 
of the main characteristics of it as so far traced. 

That these hills constitute a true moraine is evident from 
the fact that they are composed of loose material such as, 
both from the nature of the case and from observation, we 
know is actually deposited wherever the front of a glacier 
rests for any great length of time. A considerable portion 
of them consists of material which has been transported 
from various localities to the north, and deposited without 
any stratification. Some of the bowlders are unworn and 
angular, as if having been carried upon the back of the gla- 
cier. Others are partially rounded and scratched in such a 
manner as to show that they have been forced along through 
the mass of sand and gravel which everywhere underlay the 
moving field of ice. Sections, however, frequently show in 
these hills a limited amount of stratification. But this is not 
at all surprising, when we consider the manner of their forma- 
tion; for the ice itself to a certain extent forms barriers to, 
and furnishes channels for the running water which its own 
melting provides, and so would itself afford the conditions 
necessary to a partial stratification of its own deposits. 

The terminal moraine where best developed may almost 
be said to consist of innumerable ridges, knolls, and kettle- 
holes. The kettle-holes are of all sizes, and are situated in 
every imaginable position with reference to the general de- 
posit; some of them, low down toward the base of the 


BOUNDARY OF THE GLACIATED AREA. 143 


moraine, are filled to the rim with water; others are bat par- 
tially filled; while others are for the greater portion of the 
year completely dry. The angle at which the earth forming 
their sides stands is usually as sharp as the nature of the 
material will allow, and bowlders are as frequently found 
upon the inside of the rim as upon the outside. 

The origin of kettle-holes has already been explained ; 
but it is in place here to remark upon some of the general 
considerations supporting the theory already advanced.* It 
is evident, from. a” inspection of the depressions themselves, 
that they can nov be the result of erosion, since the depres- 
sions are too irregular and too deep to have been formed by 
the plunging movement of water, and the material is too 
coarse for a water deposit. In some respects kettle-holes 
resemble what are called sink-holes, frequent in limestone 
regions, where a great amount of material below the surface 
is removed in solution, leaving numerous caverns whose roofs 
eventually sink in, and form the depressions characteristic of 
such regions. But kettle-holes abound in regions where no 
such caverns could have been formed, and are distributed 
over the country according to a method which could not have 
originated by the action of underground currents of water. 

While the iceberg theory was in favor to account for the 
drift, it was not uncommon to hear these kettle-holes spoken 
of as places where icebergs had stranded, and in turning 
round and round had bored holes in the bottom of the ocean- 
bed over which they were floating; but, now that the ice- 
berg theory is abandoned, and observations are more extended, 
the origin of kettle-holes is readily understood as an inevita- 
ble part of the glacial theory itself. Any one who will in 
the early spring-time take pains to observe the melting of 
masses of ice which have been covered by ashes and other 
refuse, or which have been partially buried beneath the 
débris of earth which some spring torrent has brought down 
from a neighboring hill, will find before him a very perfect 


* See above, p. 66 et seq. 


144 THE ICE AGE IN NORTH AMERICA. 


object-lesson as to the formation of kettle-holes. All the 
elements for their production are there, in and beneath the 
accumulated débris. As the heat slowly penetrates the pro- 
tective covering, especially upon the sides, where it is the 
thinnest, it melts the ice and thus undermines the earthy 
material, which, in due time, slides down to the base, and 
thus gradually leaves a cone of ice in the middle, surrounded 
at the edges by a continuous ridge of dirt. Eventually the 
ice all melts away, and a miniature kettle-hole is formed. So 
far as I know, the application of this principle to the expla- 
nation of the extended phenomena under consideration was 
first made by the late Colonel Whittlesey,* of Ohio, in study- 
ing the Kettle range of Wisconsin. How completely this 
theory was confirmed by my study of the Muir Glacier, in 
the summer of 1886, has already been related.t 

To prevent misapprehension, it should here be remarked 
that we have not intended to affirm that the whole bulk of 
Martha’s Vineyard and Long Island consists of glacial depos- 
its. The nuclei of those islands certainly existed before the 
Glacial period, for at Gay Head, on Martha’s Vineyard, and — 
in the vicinity of Port Jefferson, on Long Island, and at 
some other places, there are extensive beds of Tertiary clay 
underlying the glacial deposits, and rising above the water- 
level. The glacial deposits simply form a capping of more 
or less thickness to these older ones. It is still trne, however, 
that the glacial deposits have determined, in the main, the 
present topographical features. 

In following the moraine across New Jersey, we find that 
beginning at the sea-level, its base rises to a height of more 
than a thousand feet, where it crosses the Blue Hills of 
western New Jersey; and everywhere its surface is character- 
ized by the knobs and kettle-holes, whose manner of for- 
mation has just been explained. 

Crossing the Delaware River, these characteristic phe- 


*Report upon ‘‘The Drift Formations of the Northwest,’ in 
“Smithsonian Contributions to Knowledge’’ 1866 


+See above, p. 57 et seq. 


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146 THE ICE AGE IN NORTH AMERIOA. 


nomena are developed in a marked degree upon the hills of 
Northampton county, Pa., running up to the base of the Kit- 
tatinny Mountain, some miles below the Delaware Water- 
Gap. West of the mountain, in Monroe county, the valley 
south of Stroudsburg is for several miles filled with the 


Fie. 47.—A glaciated pebble, natural size, from the moraine on Pocono plateau, Pennsyl- 
vania, two thousand feet above the sea, Monroe county. The strie along the longest 
diameter are well marked. 

same characteristic ridges, knobs, and kettle-holes. On going 

still farther west, and rising suddenly fifteen hundred feet to 

the plateau of Pocono Mountain-—-the southern extension of 


BOUNDARY O¥ THE. GLACIATED AREA. 147 


the Catskills—we find still the same characteristic deposits 
slightly moditied by the different conditions. A range of 
hills, sweeping around this plateau for ten or twelve miles in 
a magnificent semicircle open toward the south, was discov- 
ered, in 1881, by Professor Lewis and myself to belong to the 
extreme and true terminal moraine of the continental ice- 
sheet. South of it one may go for miles upon a level, sandy 
plateau (about two thousand feet above tide) without en- 
countering a bowlder or any foreign material; while the low 
range of hills, seventy-five or a hundred feet in height, is 


Fie. 48.—The previons pebble viewed from the edge. The reversed side was free from 
glacial marks. 


literally formed of bowlders; among which may readily be 
recognized those of granitic origin, wrenched from ledges 


hundreds of miles to the north, and transported hither across 
the valley of the Mohawk or over the broad expanse of Lake 


148 THE ICE AGE IN.NORTH AMERICA. 


Ontario. Nicely ensconced within their wooded shores, there 
are here also the numerous lakelets so often found occupying 
kettle-holes, and forming the sources of streams which issue 
from the mountain-side to water the valleys below. There 
are few more interesting regions in which to study an ancient 
terminal moraine than the plateau of Pocono Mountain, be- 
tween Tobyhanna and Tunkhannock townships, in Monroe 
county, Pa. 

Passing still farther westward, and descending to the 
North Fork of the Susquehanna, twenty miles below Wilkes- 
barre, we find a remarkable terminal accumulation of glacial 
débris filling the valley to a great depth for some distance 
above Beach Haven. In the immediate vicinity of the river, 
which was one of the great lines of drainage during the Gla- 
cial epoch, the material is more or less modified by water- 
action ; but the unmodified moraine can be clearly traced far 
up on either side of the valley. A few miles to the west- 
ward, on the other side of Huntingdon Mountain, and but ten 
or twelve miles south of the southern wall of the Alleghanies, 
the line of terminal deposits can be traced past Asbury, 
through a whole township and some miles beyond, up the 
eastern side of Fishing Creek. Through all this distance, on 
the east side of the creek, there is nothing upon the surface 
but these irregular and confused features of a well-marked 
terminal deposit ; while on the west side of the creek, not a 
sign of glacial action can be seen. But suddenly, above the 
town of Benton, the belt of confused deposits of stone and 
gravel begins to descend the eastern side, and after crossing 
the valley diagonally, rises, like a broken-down Chinese wall, 
upon the western side. 

It is important to make a cautionary remark at this 
point. The boundary so far in eastern Pennsylvania as 
here delineated is that which was determined by Professor 
Lewis and myself in 1881, but it became probable that 
there was a small margin of error in our delineation; while 
from Luzerne county on, the varied fortunes of the ter- 
minal moraine are difficult of description. The north-cen- 


BOUNDARY OF THE GLACIATED AREA. 149 


tral counties of Pennsylvania are covered with forests, and 
are cut up into gorges extremely difficult of access. Never- 
theless, in Lycoming county, upon a plateau at Rose Valley, 
three or four miles to the east of Lycoming Creek, and sev- 
eral hundred feet above it, large kettle-holes with their sur- 
rounding ridges of gravel, and their accompanying bowlders 
and striated rock-surfaces, are marked features of the land- 
scape at a height of 2,000 feet above the sea; while upon 
the west side of the creek these features are totally absent 
for some miles above. Similar developments are met, at 
occasional intervals, all along the line of the great conti- 
nental divide in Potter coutity, whence the waters flow to 
the widely separated regions of the Gulf of St. Lawrence, 
Chesapeake Bay, and the Gulf of Mexico. The same pro- 
nounced features already described mark the terminus of the 
great ice-sheet where it crossed the valley of the various tribu- 
taries entering the Alleghany River from the north, in Cat- 
taraugus county, N. Y. In that State these are specially 
noticeable at Ellicottville, at Little Valley, and upon the 
high lands upon either side of the Eastern Branch of Cone- 
wango Creek near Randolph. As the glacial margin 
swings back again to the Pennsylvania line, it is marked by 
numerous and impressive accumulations in Warren county, 
one of the most accessible and notable localities being where 
it crosses the valley of Conewango Creek at Ackley, a few 
miles above its junction with the Alleghany River at Warren. 
Here the marginal line of glacial deposits may be clearly seen 
as it descends from the highlands on the east diagonally to 
the valley, filling it to a great depth, and rising over the hills 
in its onward course to the southwest. At this point in the 
valley, as at some other places which could be mentioned, 
the northern side of the moraine is more abrupt than the 
southern. 

It was here that we made some of our first and most 
exact discoveries as to the limit of the ice west of the Alle- 
ghanies. Professor Lewis and myself, who were pursuing 
the investigations together, had already learned the charac- 


150 THE ICE AGE IN NORTH AMERICA. 


teristics of the great lines of glacial drainage extending to 
the south of the glacial limit, and of which more particular 
mention will be made in a future chapter; but it was here 
that we first detected the exact relation of these lines of gla- 
cial drainage to the great ice-movement. Coming up from 
Warren toward the glacial boundary, the valley of the Cone- ~ 
wango is seen to be filled increasingly full of gravel deposits 
arranged in terraces on either side of the small stream. The 
height of these above the stream is sixty or seventy feet. At 
first the gravel is rather fine, but is constituted largely of 
water-worn granitic fragments, which could have come with- 
in range of the stream only by glacial transportation from 
the far north. On proceeding a few miles farther north, 
these terrace deposits become more and more irregular, being 
thrown up into great ridges, and at the same time the mate- 
rial becomes less water-worn and much coarser. Below this 
point we had searched diligently in the gravel for scratched 
stones, but none were anywhere to be found. A mile or two 
from Ackley, however, we began to find pebbles upon which 
the glacial scratches could be dimly traced. They had been 
partially water-worn, but had not been rolled far enough to 
completely obliterate their glacial marks. Upon reaching 
Ackley, we found the whole valley occupied by a true gla- 
cial deposit, terminating abruptly to the north, and through 
which the stream had cut a narrow channel. The moraine 
ridge, or dam, as we might call it, rises from 100 to 150 feet 
above the present bed of the stream, and is equally well de- 
veloped upon both sides. Scratched stones and granitic frag- 
ments abound, and it is well marked upon either side of the 
creek by the characteristic kettle-holes. Above Ackley, for 
many miles, the Conewango pursues a sluggish course, and 
is bordered by extensive marshy land. The explanation of 
all this is that the ice-front remained for a somewhat pro- 
tracted period at Ackley, allowing the large accumulations 
immediately below to take place. But its retreat from Ack- 
ley for many miles northward was too rapid to permit of any 
marked terminal accumulations : 


CHAPTER VII. 


(CONTINUED. ) 


THE ATTENUATED BORDER. 


So far it has been thought best to adhere closely to the 
delineation of the glacial margin through New Jersey and Penn- 
sylvania as given in the report of Lewis and Wright in Vol. 
Z of the Pennsylvania Survey. But in the preparation of 
that report we were laboring under the false impression that 
the extreme glacial margin was always marked by a distinct 
moraine. This error was partially recognized by usin speaking 
as Professor Lewis, especially, did, of a bordering “fringe’’ 
of sporadic glacial deposits extending some distance farther 
south than the line as marked on our map. The study of 
this was taken up later by Professor Edward H. Williams and 
carried on across the state with the result that the boundary 
of the ‘‘fringe”’ or ‘attenuated border’’ was found to extend 
on an average, about twenty miles farther south than our 
“terminal moraine.’”’ Similar results were found to prevail 
in New Jersey by Professor Salisbury, Professor A. A. Wright, 
and myself. 

To be specific: The extreme glacial limit in New Jersey 
reached to an irregular line running from Bound Brook, a 
little south of Plainfield, to Riegelsville, on the Delaware, a 
few miles south of Easton, Pa. So far, land-ice evidently 
extended at onetime. The striated bowlders found by Profes- 
sor Salisbury and others still farther south were doubtless 
carried by floating ice when the land was depressed to the 
extent of about 200 feet, of which evidence will be given in 
a later chapter. 


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BOUNDARY OF THE GLACIATED AREA, 153 


In Pennsylvania it is interesting to note that the Alpine 
plant Sedum Rhodiola, long known to exist in the narrows of 
the Delaware River south of Riegelsville, marks the boundary 
of the attenuated border in the extreme east. Thence the 
line skirts the Triassic areas on the south side of the Durham 
Valley, just south of Bethlehem, turns westward to the Schuyl- 
kill at Berkeley a few miles north of Reading; thence north- 
ward on the east side of the Schuylkill River to Shoemakers- 
ville and going over the Blue Ridge Mountain in a zigzag 
line, passes through Jacksonville and Kepner to Tamaqua 
where it crosses the Schuylkill. Thence running westward it 
crosses the Little Schuylkill at Wetherill Junction four miles 
from Pottsville depot, thence westward through Ashland 
and Shamokin to the Susquehanna River a few miles south © 
of Selin’s Grove. West of Pennsylvania this attenuated 
border assumed greater and greater proportions, attaining its 
largest extent in northeastern Kansas, from which fact the 
deposits have been denominated ‘‘ Kansan Drift.’? From the 
thinness of the “‘ Kansan’? deposits and their more highly 
oxidized condition, this drift has been assumed to be vastly 
older than the deposits marked by the terminal moraine of 
Lewis and Wright and, unfortunately, have given name to the 
whole attenuated border and in popular apprehension carried 
with it the assumption that they are all synchronous in age. 
With this protest, however, it will be best to continue the 
use of the term and speak of these deposits as “ Kansan”’ 
and of the latest ones as ‘‘ Wisconsin.” 

One of the most impressive facts ascertained by Professor 
Williams concerning this earliest advance of the ice over the 
region between the Lehigh and the Susquehanna valleys was 
that of the formation of an ice-dam across the mouth of 
the Lehigh at Easton, producing a temporary lake (which 
might properly be named Lake Williams) extending from 
Allentown to Topton and there overflowing into the Schuyl- 
kill at Berkeley a few miles above Reading. The depth of water 


154 THE ICE AGE IN NORTH AMERICA, 


in this lake was 280 feet at Allentown and its outlet at Topton 
was 500 feet above tide. The shore lines can easily be traced 
along the whole distance. The overflow into the Schuylkill 
carried floating ice and glacial débris into that river so that 
considerable deposits of glacial material were made in some 
places, notably at Norristown only a short distance above 
Philadelphia. Much of the gravel in West Philadelphia is be- 
lieved by Professor Williams to have come down the Schuyl- 
kill through this channel, and through the Little Schuylkill, as 
all the coal region drained by the latter was covered by ice. 

The efficiency and comparative recency of the glacial ac- 
tion over this “‘Kansan”’ area in Pennsylvania is well shown 
at Morea, a few miles north of Pottsville, and only one mile 
north of the extreme limit of glaciation at this point. Here, 
for commercial purposes, the ‘‘Mammoth bed” of anthracite 
coal has-been stripped of its covering of “‘ Kansan till.”’ The 
coal vein here outcrops in nearly vertical planes favoring the 
percolation of water and the disintegration of the surface. 
Beginning at the top the covering consisted of from six to ten 
feet of sandy till with occasional bowlders five feet in diameter; 
below this were eighteen inches of crushed anthracite entirely 
fit for the market; then came three-fourths of an inch of rotten 
coal mixed with angular specs of slate; then one inch of sandy 
clay with rolled and angular quartzite and slate pebbles; 
then one-half inch of fine bright crushed coal; and below this 
the glaciated surface, shown in the illustration, the upper 
three-fourths of an inch of which was so soft and fully rotted 
that it could be scratched with the finger nail. Below this 
was an indefinite extent of solid bright marketable coal. The 
recency of the glaciation appears in the fact that south of the 
glacial border, only one mile away, the coal-is so disintegrated 
as to be worthless for many feet below the outcrop. At the 
same time the covering in the glaciated area is so sandy and 
porous as to be very little protection to the surface of the 
coal. 


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BOUNDARY OF THE GLACIATED AREA, 155 


Another noticeable characteristic of deposits over this 
attenuated border is that the prevailing, highly oxidized mate- 
rial is mingled with a considerable amount of fresh unoxidized 
material brought from farther north, showing that the oxidi- 
zation was mainly preglacial, and that the age of the deposit 
must be reckoned from the accession of the fresh material. 
In the effort to determine the age of these deposits from the 
extent of the oxidization, it also should be ever kept in mind 
that the ice moved first over an area whose surface had been 
deeply disintegrated and oxidized during the long ages of 
tertiary time. It was the product of this disintegration which 
was first incorporated into themass which was moved along by 
the ice, and this naturally was carried farthest. Thecontribu- 
tions made later weresuch fresher portions of therocky surface 
as had been below the action of the disintegrating agencies of 
the Tertiary period and so would be mingled with the earlier 
material wherever the ice overrode the deposits of the primary 
advance. 

_ West of the Susquehanna the ice pushed over the plexus 
of mountains south of Williamsport, rising toaheight of 1,200 
feet above the river and ending along a zigzag line bearing 
northwestward, as shown in the map, reaching the west 
branch of the river at Lock Haven. In this area several 
most interesting and even startling results were produced. 
Though the ice did not reach the valley of the Juniata River, 


' Professor I. C. White had reported at various places along the 


border of the river, especially at Huntingdon “great heaps of 
bowlder trash, both rounded and angular . . . . and 
these often very much resemble genuine drift heaps.’”’ Some- 
times these reach an elevation of 100 feet above the river. 
Later, Professor Williams found unmistakable glaciated 
stones in the corresponding high level terrace at Lewistown: 
while on the western side of Warrior’s Ridge a little above 
Huntingdon, where the Juniata cut a narrow gorge through 
the mountains there was a small deposit of erratics between 
300 and 400 feet above the river. 


156 THE ICE AGE IN NORTH AMERICA, 


All these facts became clear when it was known that the 
ice crossed the Susquehanna and advanced to the summit of 
the mountains lying between that river and the Juniata. The 
glacial gravels at Lewistown came from a stream which poured 
over the col at Adamsburg where the ice was arrested in its 
movement. The bowldery deposits farther up the Juniata 
near Huntingdon came from an immense glacial stream which 
poured over the col between the head of Bald Eagle Creek and 
a branch of the Juniata joining the main stream at Tyrone. 
Bald Eagle Valley had been occupied by a long narrow glacial 
lake occasioned by the obstruction of its mouth at Lock Haven, ~ 
where the depth of the water was 570 feet. The col above Ty- 
rone has an elevation of 1,100 feet. The shore lines of this 
temporary lake (which has appropriately been named Lake 
Lesley) can easily be traced, and is marked by great cones of 
gravel where tributary streams came in from the east. The 
erratics thrown up to such a great height on the west side of 
Warrior’s Mountain are evidently due to highand tumultuous 
water produced by an ice-gorge where the stream enters 
the narrow channel across the mountain ridge. Numerous 
evidences of the damming of the West Branch of the Sus- 
quehanna are to be found as far up as Emporium on the 
Sinnemahoning River. 

Northwestward from Lock Haven the border of the Kansan 
drift is lost in the wildernesses of Lycoming and Potter 
counties, becoming recognizable again near Coudersport, 
beyond which it disappears under the moraine of Lewis and 
Wright to reappear again on the highlands of Warren, Ve- 
nango and Butler counties west of the Allegheny River where 
the elevations rise above the flooded regions produced by the 
ice-dams which reversed the drainage of the whole basin 
west of the Alleghenies. A simple illustration shows the 
probable overlapping of borders as suggested by Professor 
Williams. 

The history of the reversal of the drainage of the Alle- 


Fie. 50—Lake Lesley. EH. Emporium. H. Harrisburg. Sb. Sunbury. Wp. Williams- 
port. Ty. Tyrone. 


A Approximate 
SN Kaysan Aper 
. 


° ” ao do 40 mime & | 


| | 
Pe 


Fie. 51—Advance of Wisconsin Ice over the Kansan Border near the apex of New York, 


158 THE ICE AGE IN NORTH AMERICA, 


gheny might seem to be more appropriate to the chapter on 
Glacial Dams, Lakes, and Waterfalls, but it is so intimately 
related to the facts connected with the extreme extension of 
the continental glacier in the Appalachian region that we 
introduce it here, expecting the reader to refer to it again for 
facts which have an important bearing on later theoretical 
discussions. In itself, however, it is one of the most interesting 
problems ever presented to the geographer and the geolo- 
gist: I am permitted to quote freely from the unpublished 
report of Professor E. H. Williams upon the subject, and to 
make use of his extensive collection of facts. 


LAKE ALLEGHENY. 


Professor Williams writes, ‘“ ‘Kansan’ drift throughout. 
Pennsylvania is characterized by native copper. I have a 
- piece from Warren (40 feet below the surface), and farmers 
have come to me at Bethlehem to come and see their “cop- 
per mine.’ Mr. Albert G. Rau, Dean of the Moravian Col- 
lege has, at numerous points, picked up rolled fragments 
from ‘Kansan’ gravels. This seems to point to a Lake Su- 
perior passage by the ice—hence the glacier which first in- 
vaded this part of the state came from the northwest, and 
therefore moved against the drainage and presented so effect- 
ual a dam that, with the exception of the hilltops, north- 
western Pennsylvania and adjacent New York were sub- 
merged by a lake whose eastern shores in Pennsylvania were 
the highlands of Potter County and their extension south- 
ward, while McKean County extended into it like a broad 
promontory deeply gashed by its river systems. The name 
Allegheny is proposed for this lake which originated long be- 
fore the advent of glacial ice to the immediate region and 
which, being but slightly drained subglacially, sent its wa- 
ters southwards over the cols into other drainage systems. 
As the glacier advanced it constricted the area of escape and 
when it reached the line of the present Allegheny it formed, 


BOUNDARY OF THE GLACIATED AREA, 159 


with the eastern highlandsa trough through which the torrents 
cut their way southward. The presence of high water sedi- 
ment at Franklin shows that the col which imposed the height 
to the lake was south of that place, and also shows that all 
intervening cols were submerged and the drainage systems 


Fic. 52—Lake ampanerr+ B. Barnesville. C. Clarendon. F. Franklin. /. Irvine. 
. Oil City. TJ. Thompsons. W. Warren. 


between them aggraded. When the most distant and restrain- 
ing col became degraded so that the interior ones came within 
the area of scour they were cut down gradually and readily, 
as the porous and loosely cemented sandstones rapidly yield 
to water carrying only its own sands, and the shales carry 


160 THE ICE AGE IN NORTH AMERICA. 


strata so highly jointed that they collapse under a slight im- 
pact, and undermine the overlying and more resistant strata. 
The result was an aggradation of oldersystemsto the levelof the 
older cols andthe present alternations of theold aggraded val- 
leys with low angles of slope and gorges varying from a steep 
V-shape to one with nearly vertical walls extending far below 
the present water level and attesting to the torrential flows 
which degraded them.” 

In estimating the significance of these facts, however, it 
is important to bear in mind the extensive changes of land 
levels which took place before, during, and after the Glacial 
period. (1) It will be shown in a later chapter that there 
was. extensive elevation of the glaciated region in Tertiary 
times increasing in extent towards the north. In all prob- 
ability this amounted to more than 2,000 feet in the central 
part of the glaciated area. This, in itself, may have had 
something to do in reversing the drainage of many northerly 
flowing streams. 


(2) But at the close of the Glacial period the northerly 
areas of the glaciated region were depressed so that they stood 
at Montreal 600 feet lower than the present level, and farther 
north still lower. It is impossible to tell how far south this 
glacial depression extended in the northern part of the United 
States. 


(3) Since the retreat of the ice there has been a differ- 
ential re-elevation of the glaciated area increasing towards 
the north, and amounting to 600 feet at Montreal and 1,000 
feet farther north. The axis about which this differential 
re-elevation revolves seems to run east and west through 
Central New York and the basin of Lake Erie. In estimating, 
therefore, the height of the col, in the lower Allegheny or 
middle Ohio Valley, which determined the level of Lake 
Allegheny we must not forget that this differential northerly 
depression during glacial times may make the water levels 
in the upper part of the lake appear to be higher than they 


BOUNDARY OF THE GLACIATED AREA. 161 


absolutely were. But we will give the facts as they now 
appear. 

The facts will be best appreciated by somewhat detailed 
study of the portion of the Allegheny Valley which passes 
through Warren and McKean counties in Pennsylvania and 
Cataraugus County in New York. The upper Allegheny 
descends from the high tableland of Potter and McKean 
counties in a northerly direction, and consequently was 
obstructed by the advancing ice, both of the Kansan and of 
the Wisconsin epochs. Abundant evidence of the slack water 
thus produced is seen all along this part of the valley, from 
Coudersport and Keating through Port Allegheny and Turtle 
Point down to Salamanca in New York where the stream 
turns abruptly to the south. But the evidences of a flooded 
condition of the valley at the time of the extreme extension 
of the ice still continues down stream well-nigh to the Ohio 
River. Everywhere along the course of this valley fans of 
gravel appear at the level of the glacial high water, wherever 
tributary streams come in from a higher level. At Warren 
this fan is 400 feet above the present water level and at Frank- 
_ lin, 650 feet. 

In the words of Professor Williams’ report, ‘‘ The affluents 
of the Allegheny show traces of high water. Those flowing 
from the glacier are generally aggraded and reversed: those 
from the Pennsylvania highlands are also aggraded but with 
local material. The narrowness of their valleys allowed the 
removement of sediment when the water level brought the 
bottoms within the area of scour, and it is only in favored 
places that the evidences remain. Some, however, as Red 
Bank Creek, and the Kiskiminetas-Conemaugh system show 
abundant traces of deepsedimentation. . . . At times 
the conjunction of sudden bends in the main stream and the 
debouchment of short side valleys which branch from thesame 
area have caused eddies or deflections of the main stream and 
have aggraded the side valleys so as to resemble portions 
of a river channel at elevations higher than the present one.” 


162 THE ICE AGE IN NORTH AMERICA, 


The most interesting collection of facts appears in the 
vicinity of Warren at the junction of Conewango Creek and 
the Allegheny River. With little doubt the preglacial drain- 
age flowed from some distance south of Barnesville northward 
through Clarendon and Warren into the Conewango and 
thence on into the Lake Erie basin, and at a level considerably 
lower than that of the present river. : 

The rock trough of the Conewango is much wider than that 
of the Allegheny for several miles up the stream, showing that 
the preglacial drainage was through the Conewango. This 
greater breadth continues down the Allegheny to Irvine, and 
thence up the Brokenstraw to the glacial limit. Below Irvine 
the trough of the Allegheny again becomes constricted through- 
out almost its entire course. Usually its lower rocky trough 
below this point is not more than three-fourths as wide as it 
is above Irvine, and at one point near Parker its width is 
less than half that in the upper part of the valley. 


But the broad preglacial trough of the Conewango ex- 
tends across the Allegheny through Stoneham and Clarendon 
to Barnesville. The gravel deposits here are of the most 
interesting and significant character. East of Warren upon 
a rock shelf 250 feet above the present stream there is an 
extensive gravel deposit from twenty to fifty feet in thickness, 
containing many Canadian pebbles, and continuous with 
and forming a part of undisturbed gravel strata extending 
down the side of the trough to the river level. It is note- 
worthy also that the lower part of this deposit for a consider- 
able depth is fine sand, and at the bottom blue clay, indicating 
deposition in still water. Crossing the Allegheny to Stoneham 
we find here also a gravel deposit overlying deposits of fine 
sand and blue clay containing frequent logs of trees such as 
now cover the hills, and extending to a depth of 160 feet 
below the surface in the middle of the trough. South of this 
is a cranberry swamp two or three miles in length extending 
to Tiona, where we again meet a gravel deposit filling a 


BOUNDARY OF THE GLACIATED AREA, 163 


buried valley as deep as that underlying the swamp and the 
gravel at Stoneham. But while the Stoneham deposit con- 
tains Canadian material, that from Tiona to Sheffield consists 
wholly of local material which has been brought down from 
the sides of the mountain to the east and south. 

Here again an interesting thing occurs. The gravel 
deposit between Sheffield and Barnesville rises to the ‘level 
of a col which leads through a precipitous gorge into and down 
the Tionesta River reaching the Allegheny at the town of the 
same name. But the northern branch of the present Tionesta 
rises a considerable distance west of Stoneham; the deposit 
at Stoneham being the watershed between that place and 
the Upper Allegheny only a few miles to the north. From 
Clarendon to Barnesville this branch flows over a preglacial 
trough nearly 200 feet in depth, then the present stream 
occupies for the rest of its course a narrow rocky trough bor- 
dered only in a slight degree with gravel deposits. 

The explanation of this, as already intimated, is that upon 
the obstruction of the northerly flowing preglacial stream 
through the Conewango Valley, deep slack water was produced 
in the Upper Allegheny Valley, the depth being regulated by 
the height of the highest col at the south. The depth of the 
water at Clarendon and Warren was about 500 feet, as shown 
by the depth of the buried rock bottom of the river at Warren 
added to the height of the gravel terraces in the vicinity of 
Clarendon. In such depth of water, held in check by an 
obstructing col somewhere at the south the lower portions 
were stagnant so that blue clay and fine quicksand would 
settle and this is what is found to a thickness of about 200 
feet. Above this approximate level coarse sand and gravel, 
with occasional large pebbles, was spread in dumps and fans 
wherever tributary streams brought in material, which was 
pre-eminently the case where streams entered from the 
glaciated region. Such are the terraces of glacial gravel 
already described just east of Warren, and a still larger and 


164 THE ICE AGE IN NORTH AMERICA, 


higher one a mile, or so, above the mouth of the Conewango 
in the narrower valley of the Allegheny. 

A still more interesting and significant dump lies about 
one-half mile west from Clarendon where there is an extensive 
gravel deposit running parallel to the valley and resting on 
the older local slopes. The surface of this deposit is 160 feet 
above the present level of the valley. Its depth, however, as 
shown by numerous driven wells is 308 feet, of which the upper 
sixty feet is gravel containing a noticeable amount of granitic 
material, underlaid by 148 feet of sand with a small amount 
of gravel, and this in turn by 100 feet of clean clay. In this 
clay the drill, in some cases, went through a stratum of logs. 

Anticipating, somewhat, the more comprehensive discus- 
sions of the chapters on Preglacial and Glacial Drainage, the 


order of events as indicated by the facts in this interesting ~ 


locality will be found to be as follows: 

In early and middle Tertiary times the drainage of the 
Allegheny and upper Ohio basins was northward while the 
land levels were lower in the north than they were in the south. 
During the later part of the Tertiary period an elevation of 
land went on over all the region afterwards covered with 
elacial ice, being greater in the north than inthesouth. This 
differential elevation perhaps had much to do with the reversal 
of the drainage lines of which we have such abundant evidence. 
But the advance of the glacial ice front against the northerly 
lines of drainage completed the reversal, so that unprecedented 
floods of water poured over the cols between the reversed 
channels, wearing them down with great rapidity as is shown 
by the narrowness of the troughs and steepness of the sides 
of the gorges through various sections of the present drainage 
lines. The position of the highest col was probably a consider- 
able distance below the upper end of the Ohio River not 
unlikely a short distance below Wheeling, W. Va., as suggested 
by Chamberlin. 

In this view, the rock erosion of the Allegheny and Ohio 


BOUNDARY OF THE GLACIATED AREA. 165 


valleys ismainly preglacial, and the high level gravel terraces 
which line the troughs through their entire extent were de- 
posited during the various stages of this rock erosion. The 


fpases : ra 


' 

‘ 

- 
: 
i 
' 
i 
‘ 
' 


© deme 


Scale Wales 
tt - 1¢ {t 
C209, 
cet , 
Cdl 


Fie. 53.—Map of Upper Allegheny Valley, Pa. 


difficulty of accepting this hypothesis, arising from the fact 
that it involved believing that the deposition of the high 
level terraces went on without the filling of the lower and 


166 THE ICE AGE IN NORTH AMERICA, 


_ narrower portions of the rock gorges through which the stream 
_ runs, was met by the sagacity of Professor E. H. Williams, 
whose intimate knowledge of the subject obtained as a hy- 
draulic and mining engineer has enabled him to make the 
whole process clear. This is checked by the fact that the 
planes of sedimentation uniformly follow the contours of 
the underlying rocks and show that, first, those contours 
were carved out before the deposition began and, second, 
that the later sediments poured over them as in the case of 
ordinary bars and fans and varied from coarse to fine with 
the velocity of the current. 

As tidal currents scour out and keep clear certain channels 
where their action is concentrated, so a powerful river tor- 
rent scours out its main channel to a great depth, while it 
throws up and deposits its sediment both coarse and fine upon 
the higher bordering levels whenever there is a bend in the 
trough changing the course of the current, or wherever there 
is a strong tributary coming in at a broad angle. The forces 
involved are nothing other than those which form an ordinary 
flood plain, except that they are extremely vigorous. On 
following down the Allegheny and Ohio valleys all the high 
level gravel terraces can be accounted for by the action of 
the tumultuous torrents from the melting ice of the closing 
stages of the Glacial period as they poured through the 
tortuous channel as it now exists. 


showing bar on top of slack water sands. 
g and elevation above Warren. 


= 
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wal 


CHAPTER VII. 


(CONCLUDED) 
THE GLACIAL BOUNDARY WEST OF PENNSYLVANIA. 


Through Columbiana county, Ohio, as in the adjoining 
counties of Pennsylvania, there is, to the south of the heavy 
accumulations of till, a fringe of thinner glacial deposits from 
one to three miles wide. Over this margin there are scat- 
tered evidences of glacial action, consisting of granitic bowl- 
ders and patches of till here and there upon the highlands, 


* See G. F. Wright, “The Glacial Boundary in Ohio. Indiana, and Ken- 
tucky,” Western Reserve Historical Society; also “Ohio Geological Report,” 
vol. v, pp. 750-771; T. C. Chamberlin, “ Extent, etc., of the Wisconsin Ket- 
tle Range” (‘Transactions of the Wisconsin Academy of Sciences,” vol. iv); 
“‘ Geological Survey of Wisconsin,” vols. ii and iii (Madison, 1877-80); “ Pre- 
liminary Paper on the Terminal Moraine of the Second Glacial Epoch” (United 
States Report); George H. Cook, “ Annual Reports for New Jersey for 1877, 
1878”; G. M. Dawson, “On the Superficial Geology of British Columbia” 
(“Quarterly Journal of the Geological Society, 1878,” vol. xxxv, p. 89); J. W. 
Dawson, “ Changes of the Coast-Level in British Columbia” (‘‘ Canadian Natu- 
ralist,”” April, 1877); G. K. Gilbert, “On Certain Glacial and Post-Glacial Phe- 
nomena of the Maumee Valley, Ohio” (‘‘ American Journal of Science, 1871,” 
vol. ci, p. 339); C. H. Hitchcock, “ Moraines of North America” (‘‘ Popular Sci- 
ence Monthly,” 1881); Clarence King, “‘ United States Geological Explorations of 
the Fortieth Parallel,” vol. i; “Systematic Geology ” (Washington, 1878); Lewis 
and Wright, “‘ Report on the Terminal Moraine in Pennsylvania and Western 
New York, Second Geological Survey of Pennsylvania, Z”’; Warren Upham, 
“The Northern Part of the Connecticut Valley in the Champlain and Terrace 
Periods” (“ American Journal of Science, 1877,” vol. exiv, p. 459); ‘‘ The For- 
mation of Cape Cod” (“American Naturalist, 1879,” vol. xiii, pp. 489, 552); 
“Geological Survey of New Hampshire,” vol. iii (1878); ‘Geological and Natu- 
ral History Survey of Minnesota” (Report for 1879); “Terminal Moraines of 
the North American Ice-Sheet” (“American Journal of Science, 1879,’ vol. 
exvili, pp. 81, 197); Charles Whittlesey, “‘ Fresh-Water Drift of the Northwest- 
ern States” (“Smithsonian Contributions, 1866,” vol. xv); N. H. Winchell. 
“The Drift Deposits of the Northwest” (‘‘ Popular Science Monthly,” vol. iii, 
pp. 202, 286); “Geology of Minnesota” (Annual Reports, 1872, etc.). 


*See also full lists given in the Appendix. 


THE ICE AGE IN NORTH AMERICA. 


168 


at an elevation a from 300 to 500 feet above the Ohio 


River. North of this fringe the till is continuous, and every- 


o 
& 


where of great depth. At Palestine, on the eastern edge of 
the county, and at New Alexandria, near the western side, 


NY 


Ss 


I 


illersbu) 
ae pe oa 


Pville 


QQ 
YY \\ 


RNA 
RQ 


Xt Sy . 
\\ 


\\ 


\\ \ MAK 
\ 
UN AN 


MMMM 


SCALE OF MILES 


and the glacial 


deposits are marked, in a moderate degree, by the knobs and 


Fig. 56.—Map of the glaciated region of Ohio, showing a part of its extension in 
: Kentucky. 
kettle-holes characteristic of the moraine upon the south shore 
of New England. A mile or two west of Canton, in Stark 


wells are reported in the till fifty feet deep. This is upon 


the highest land in that part of the country, 


BOUNDARY OF THE GLACIATED AREA. 169 


county, the accumulations of glaciated material are upon a 
scale equal to anything upon Cape Cod. The northern part 
of Holmes county is covered with till, which is everywhere 
of great depth, and in numerous places near the margin dis- 
plays, though in a moderate degree, the familiar inequalities 
of the New England moraine. After the southern deflec- 
tion in Knox county, the glaciated region is entered near 
Danville, from the east, on the Columbus, Mount Vernon, 
and Akron Railroad, through a cut in till a quarter of a. 
mile iong, and from thirty to forty feet in depth. At the 
old village of Danville, near by, upon a neighboring hill, 
wells are reported as descending more than a hundred feet 
before reaching the bottom of the till. Through Licking 
county, both north and south of Newark, the depth of the 
glacial envelope is great up to a short distance of its east- 
ern edge. At the old canal reservoir, in Perry county, the 
characteristic features of a moraine come clearly out. The 
hill just to the south of this, on which Thornville is built, is 
a glacial deposit in which wells descend from thirty to fifty 
feet without striking rock. This is upon the highest land 
in the vicmity. The reservoir itself seems to be simply a 
great kettle-hole. All through Fairfield county the glacial 
accumulation is of a great depth down to within a very short 
distance of its margin. 

But perhaps the most remarkable of all the portions of 
this line in Ohio is that running from Adelphi, in the north- 
east corner of Ross county, to the Scioto River. The accu- 
mulation at Adelphi rises more than two hundred feet above 
Salt Creek, and continues a marked feature in the landscape 
for many miles westward. Riding along on its uneven 
summit, one finds the surface strewn with granitic bowlders, 
and sees stretching off to the northwest the magnificent and 
fertile plains of Pickaway county, while close to the south of 
him, yet separated by a distinct interval, are the cliffs of 
Waverly sandstone, rising two hundred or three hundred 
feet higner, which here and onward to the south pretty 
closely approach the boundary of the glaciated region. 


170 THE ICE AGE IN NORTH AMERICA. 


Through the southeastern corner of Highland county, and 
the northwestern corner of Adams, the terminal accumula- 
tions are less marked than in Ross county ; still, their bound- 
ary can be accurately and easily determined. It approaches 
the Ohio River, in the vicinity of Ripley and Higginsport in 
Brown county, and crosses it from Clermont county, entering 
Kentucky half a mile north of the line between Campbell 
and Pendleton counties in that State. Cincinnati was cov- 
ered with ice during a portion of the period. There are un- 
doubted glacial deposits within the bounds of the city at the 
railroad station at Walnut Hills, and near Avondale, at a 
height of about four hundred feet above the river. At North 
Bend, twenty miles below Cincinnati, the tunnel of the rail- 
road leading from the Ohio to the Great Miami River is 
through an indubitable glacial accumulation which rises two 
hundred feet above the river. The northwestern part of 
Boone county, Ky., was also covered with the ice toa dis- 
tance of several miles south of the Ohio River. 

Through Indiana the glacial boundary, after following 
the Ohio River to within ten or twelve miles of Louisville, 
Ky., suddenly bends to the north, leaving a large ’triangular 
portion of the State unglaciated. The base of this ungla- 
ciated triangle extends from Louisville to the Illinois line, 
and its apex is about thirty miles south of Indianapolis. 
The exact course of this part of the boundary is along a line 
running from the neighborhood of Louisville northward 
through Clark, Scott, Jackson, Bartholomew, and Brown 
counties to Martinsville in Morgan county, where it again 
turns west and south nearly parallel with, and west of, the 
West Fork of White River, through Owen, Greene, Knox, 
Gibson, and Posey counties, crossing the Wabash River 
into Illinois, near New Harmony, the seat of Owen’s cele- 
brated socialistic experiment. 

In Illinois the line continues in a southwesterly direction 
through White, Gallatin, Saline, and Williamson counties, 
where it reaches its most southern limit near the northern 
boundary of Johnson county, fifty or sixty miles north of 


BOUNDARY OF THE GLACIATED AREA. 171 


s SN I 
>. 1 
R SN LIM, : ! . 
\ ‘ AAs a © 
AN » Wy \. ' ' ! + 
SY YS MAAR t ty 
3A) \ WY » 
\ \\\ AAW | 
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\ A AN | 
\\ : s 
\ ~ \\ \ AS a 
AQ Xn : é 
MQ . \\\\ \ \) \ SIAN 
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Cairo, a little below latitude 38°. From Williamson county 
it starts westward upon its final course to the north, reaching 
the Mississippi River, near Grand Tower, in Jackson county. 
From this point to the vicinity of St. Louis the Mississippi 
runs nearly southeast, so that the glacial boundary in its 


172 THE IVE AGH IN NOR1TH AMERICA. 


northwest course is coincident with the bluffs on the north- 
east side of the river through Jackson, Randolph, and Mon- 
roe counties, IIL. 

_ So far I have traced the southern boundary myself, and 
the information here given is nearly all at first hand. Beyond 
the Mississi} ‘pl competent members of the United States 
Geological Survey have traced the course approximately to 
the Pacific Ocean. From these data we know that across 
- the State of Missouri the Missouri Itiver approximates closely 
to the glacial limit. The line enters Kansas a little south of 
Kansas City, and runs nearly west for a hundred miles to 
the vicinity of Topeka, where it curves northward, crossing 
the State of Nebraska about one hundred miles west of the 
Missouri River, and reaching the southern line of Dakota, 
near the junction of the Niobrara and the Missouri. In 
eastern Kansas and Nebraska the exact limits of the glaciated 
area appear, from the reports, to be somewhat difficult of 
determination. It would seem that the action of water and 
floating ice was predominant in determining the character 
of the glacial deposits over that region, and the theory is 
plausibly suggested by Professor Todd that the extension 
of the ice beyond the Missouri formed glacial dams across 
the valleys of the Kansas and Platte Rivers, so as to 
maintain for a short period temporary lakes of a consid- 
erable extent, which received and distributed the bowlder- 
laden fragments of ice, as well as the finer elements of the 
glacial deposits. The most of the glaciated portion of these 
States is deeply covered with fine loam, or doess, which is 
probably a water deposit, and, as we shall hereafter see, is on 
good grounds believed by Chamberlin and Salisbury to be 
an “assorted variety of glacial silt directly derived from gla- 
cial waters.” * 

Through Dakota the glaciated region is bounded by a line 
which runs northward from near the junction of the Niobrara 


* “ Preliminary Paper on the Driftless Area of the Uppcr Mississippi Val- 
ley,” by Thomas C. Chamberlin and Rollin: D. Salisbury, in the “Sixth Annual 
Report of the United States Geological Survey,” p. 304. 


BOUNDARY OF THE GLACIATED AREA. 173 


and Missouri Rivers, and keeps pretty close to the west edge 
of the river trough as far up as the mouth of the White 
River. Beyond this it breaks over the western edge of the 
trough for a short distance, and keeps approximately parallel 
with the river, from five to ten miles west of it, until reach- 


Struthers § Oo., Bngr’s, N.Y. 


Fig. 58.—Glaciated region of southern Ilinois. 


174 THE ICE AGE IN NORTH AMERICA. 


ing the vicinity of Oahe, a few miles above Pierre, at the 
mouth of Bad River. From this point to the mouth of the 
Cheyenne glacial deposits do not encroach upon the plateau 
to the west. But, above the mouth of the Cheyenne, the 
line strikes off farther west, and crosses the Moreau River 
about forty-five miles back from the Missouri, and the Grand 
and Cannonball Rivers at about the same distance. The 
Northern Pacific Railroad passes from the glaciated to the 
unglaciated region at Sims Station, about thirty miles west 
of Bismarck. 

In the chapter upon ‘‘ Terminal Moraines” we will speak 
more fully of the portion of Dakota lying east of the Mis- 
souri River; but west of the Missouri the deposits belong to 
what we have denominated the fringe, or what President 
Chamberlin perhaps more appropriately calls “the attenuated 
border.” This portion of the boundary I had the privilege of 
studying in the summer of 1888, driving some hundreds of 
miles through the Indian reservation, extending from Fort 
Yates southwestward to the Moreau, and thence southeast- 
ward to the vicinity of Pierre. Here I found the border, 
although somewhat attenuated, to be pretty sharply detined. 
The glacial marks, however, consisted almost wholly of 
bowlders and rather coarse gravel, and was pretty evenly dis- 
tributed over the surface of the plateau. The formation of 
the region is cretaceous, so that it is easy to recognize the 
Laurentian bowlders. In size these sometimes attain a diame- 
ter of four or five feet, and frequently almost cover the 
ground. The elevation attained by them runs up to about 
six hundred feet above the river. We found, however, no 
scratches upon these bowlders, nor were there any exposures 
of till or unstratified deposit, so characteristic of the terminal 
moraine and of the central portion of the glaciated area. 
But from my own experience I have no hesitation in classify- 
ing these deposits with those produced by direct action of the 
glacier. They are what would naturally occur on the attenu- 
ated margin of the ice-sheet. . 

I found evidence, also, of a temporary line of marginal 


=, 


| 
| 
. 


BOUNDARY OF THE GLACIATED AREA. 175 


drainage, which consisted of a broad, level-topped gravel 
deposit from four hundred and fifty to five hundred feet 
above the present bed of the Cheyenne River.* This old river- 
bottom is about two miles wide, and, where we crossed it, 
extended as far as the eye could reach both up and down the 
valley. Subsequently Mr. Riggs found that it joined the 
valley some miles above from the northwest. The gravel is 
rather fine and well worn, and there is only an occasional 
bowlder from one to two feet in diameter to be found upon 
the surface. On the higher levels there are no traces of the 
deposit. It has, therefore, as already said, the appearance of 
marking a marginal line of drainage, which, north of the 
Moreau River, was thirty or forty miles west of the Missouri, 
but which joined the Cheyenne just west of Fox Ridge, and 
followed that valley down to the vicinity of the Missouri, 
and ever after kept near its trough till the river passed out of 
the Territory at the Nebraska line. 

Soon after crossing the Northern Pacific Railroad in 
Dakota, the glacial boundary turns abruptly to the west, 
crossing the Yellowstone in Montana near Glendive. We 
give the delineation beyond this point in the words of Presi- 
dent Chamberlin: 

“ Passing north of the Judith Mountains, it again touches 
the Missouri in western Montana, near the mouth of the Ju- 
dith River, but at once swings away to the southward, to again 
strike and cross the river forty miles above Fort Benton, and 
about the same distance from the Rocky Mountains. Thence 
it curves rapidly to the northward, crossing the national bound- 
ary at the very foot-hills, and thence skirts them northward 
to the limits of present determination. This is the outline 
of the great northeastern sheet of drift. Along the Rocky 
Mountains, within the United States, it barely comes in contact 
with demonstrable glacial formations from the adjacent mount- 
ains, though widely intermingled with mountain ‘ wash.’ ” t 


* The elevations are kindly furnished me by Rev. Thomas L. Riggs, of Oahe. 
+ “Proceedings of the American Association for the Advancement of Sci- 
ence,” vol. xxxv, 1886, pp. 196, 197. 


176 THE ICE AGE IN NORTH AMERICA. 


In the chapter upon “Terminal Moraines” we will speak 
of the extension of the Missouri coteau into British America, 
as determined by Dr. George M. Dawson. But, while this 
eoteau is the limit of the heavier accumulations of Laurentian 
drift, it is evidently not the limit of the extent of glacial ice, 
for over an indefinite border to the west of it there is, accord- 
ing to Dr. Dawson, a large percentage of Laurentian mate- 
rial, amounting to nearly fifty per cent of the surface aceumu- 
lations, mingled with about the same proportion of quartzite 
drift brought down from the Rocky Mountains by the numer- 
ous streams originating in them. Dr. Dawson says that these 
Laurentian and eastern limestone bowlders continue to occur 
to within twenty-five miles of the base of the Rocky Mount- 
ains, and up toa height of 4,200 feet above tide. The dis- 
tance of these traveled blocks from the nearest part of the 
Laurentian region is about 700 miles. Beyond this point, to 
the west, eastern and northern rocks are not found. The 
elevation of this marginal drift is about 2,000 feet above the 
present height of the Laurentian plateau from which it came.* 

“To the westward, in the valleys of Flathead, Pend 
D’Oreille, and Osoyoos Lakes, and of Puget Sound, are 
massive deposits of drift, partly of northern and partly of 
iocal mountainous derivation. The Pend D’Oreille and 
Puget Sound deposits appear unquestionably to be tongues 
of the drift of British Columbia, which, if not constituting 
a continuous mantle, at least passes beyond the character of 
simple local mountain drift.” + 

In the Rocky Mountain region and to the westward there 
were formerly extensive glaciers in Montana, Wyoming, 
Colorado, Utah, Nevada, and California, where now they are 
almost entirely absent. But the glaciation of this region was 
never general. According to Whitney, there are no signs 
of ancient giaciers in western Nevada, though some of the 
mountains rise to a height of 10,000 feet. In the east Hum- 


* See the “ Quarterly Journal of the Geological Society,” vol. xxxi, 1875. 
+ See Chamberlin, as above. 


————————— ee 


Se ae 


and 


BOUNDARY OF THE GLACIATED AREA. 177 


boldt range, local glaciers once existed in all the higher por- 
tions. In some of the valleys they extended for seven or 
eight miles. In Utah the Wahsatch Mountains were the 
chief center of local glaciers. The principal mountain-mass 
is about fifteen miles wide, and peaks above 10,000 feet high 
are numerous. Th> glaciers formerly radiating from this 
mass did not, however, reach a very low level. In Colorado 
there are evidences of former glaciers only above the 10,000- 
foot line. Beyond that line, such valleys as those occupied 
by the head-waters of the Platte and Arkansas Rivers were 
once filled with glaciers whose terminal moraines, in some 
cases, formed dams of great extent, and thus gave rise to 
temporary lakes. The most sonthern point at which signs 
of local glaciers in the Rocky Mountains have been noted is 
near the summits of the San Juan Range in southwestern 
Colorado. Here a surface of about twenty-five square miles, 
extending from an elevation of 12,000 feet down to 8,000 
feet, shows every sign of the former presence of moving ice. 
Northward of Utah and Colorado the signs of former glacia- 
tion are also of the same local character—that is, glaciers 
everywhere radiated from the higher mountain-masses, and 
extended a short distance down the cafions and valleys. The 
Upper Cafion of the Yellowstone, in the famous park, was 
filled with glacial ice to a depth of 1,600 feet, and glacial 
marks were abundant down to the vicinity of Livingston. 

The glaciers of the Sierra Nevada and Cascade Range in 
California, Oregon, and State of Washington were on a 
much grander scale than those in the Rocky Mountains; 
but, in the one case as in the other, the glaciated areas are 
local, and, except in the state of Washington, not connected 
with the grand movement farther north. 

Upon this point Mr. Clarence King, whe had most care- 
fully explored the region, writes : 


In the field of the United States Cordilleras, we have so 
far failed to find any evidence whatever of a southward-mov- 
ing continental ice-mass. As far north as the upper Colum- 


178 THE ICE AGE IN NORTH AMERICA. 


bia River, and southward to the Mexican boundary, there is 
neither any bowlder-clay nor scorings indicative of a general 
southward-moving ice-mass. On the contrary, the great areas 
of Quaternary material are evidently subaérial, not subglacial. 
The rocks outside the limit of local mountain glaciers show no 
traces either of the rounding, scoring, or polishing which are 
so conspicuously preserved in the regions overridden by the 
northern glacier. Everything confirms the generalization of 
Whitney as to the absence of general glaciation. 

Wherever in the fortieth parallel area a considerable mount- 
ain-mass reached a high altitude, especially when 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, which can always be traced 
to its local source. In extreme instances, in the Sierra Nevada 
and Uintah Ranges, glaciers reached forty miles in length, and, 
in the case of the Sierra Nevada, descended to an altitude of 
2,000 or 2,500 feet above sea-level. Over the drier interior 
parts of the Cordilleras the ancient glaciers usually extended 
down to between 7,000 and 8,000 feet above the sea. In the 
case of the Cottonwood Glacier of the Wahsatch, a decided ex- 
ception, the ice came down to an altitude of 5,000 feet. .. . 

Not more than a thirtieth part of the entire surface of the 
fortieth parallel area was ever covered by glacial ice. It is 
characteristic of the cafions of these extinct glaciers that they 
give evidence of a gradual recession of the ice from its greatest 
extension until it is entirely melted. This retiring from its 
greatest bulk was not a continuous retrogression, but was 
marked by pauses at certain places long enough to permit the 
accumulation of considerable terminal moraines. In ascend- 
ing one of the larger cafions, as of the southern Uintah, there 
is observed a series of successive terminal moraines, and in 
passing to the upper heights of the ranges it is found that, in 
the great snow amphitheatres, glacial markings, rock-polish- 
ing, and the arrangement of morainal matter are evidently 
fresher than in the lower levels or points of greatest exten- 
sion. 

Whatever the greater causes may have been, the Cordilleran 
surface south of the State of Washington was free from an ice- 


wi el 


BOUNDARY OF THE GLACIATED AREA. 179 


sheet, and the only ice-masses were small areas of local glaciers 
which did not cover two per cent of the mountain country. 
Supposing the arctic land configuration to be as now, and 
a new oscillation of climate to bring on the conditions of a 
glacial period, it is certain that the present ice-masses would 
form the nuclei of new northern ice-fields, and Greenland 
would probably be the point from which the glaciers would 
move southward to cover eastern America ; and the absolute 
distance from such a center would have something to do with 
the failure of the ice to override the Cordilleras. Dawson’s 
suggestion of a great center of dispersion in Alaska, where an 
elevated and broad highland fronts the moisture-laden ocean- 
wind, has, it seems to me, a high degree of probability in ac- 
counting for the southerly-moving ice of British Columbia with- 
out recourse to that refuge of pure imagination, a polar cap.* 


With this agrees the testimony of Mr. I. C. Russell, in 
his report on the “Quaternary History of Mono Valley, 
California,” the advance sheets of which I have been kindly 
permitted to see. He writes: 


The Sierra Nevada during the Glacial epoch was covered by 
an immense 7évé field, which probably stretched continuously 
from a little north of latitude 36° nearly to latitude 40°. The 
width of this belt of perpetual snow must have been irregular, 
conforming to the present topography of the summit of the 
range, but it probably had an average width of between ten 
and fifteen miles. From beneath this snowy mantle trunk gla- 
ciers flowed both east and west down the flanks of the range. 

The evidence is such as abundantly to justify the conclu- 
sion that the ancient glacial system of the Sierra Nevada was 
local, and had no connection with a northern ice-sheet. The 
glaciers were clustered about and radiated from the higher por- 
tion of the range in the same manner as from the contempo- 
rary névé fields of the Wahsatch and Uintah Mountains. t 


* “Systematic Geology” in the “ United States Geological Exploration of 
the Fortieth Parallel,” 1878, pp. 459-461, 464. 

+ See the “Eighth Annual Report of the United States Geological Survey,” 
pp. 327, 328. 


180 THE ICE AGE IN NORTH AMERICA. 


The ancient area of glaciers in the Sierra Nevada Mount- 
ains was chiefly confined to the western slope, and was most 
remarkable in Tulare, Fresno, Mariposa, and Tuolumne coun- 
ties, California, where, as we have seen, glaciers still continue 
to exist. There are abundant marks of these ancient ice- 
streams in the upper valleys of Kings, San Joaquin, Merced, 
and Tuolumne Rivers. In the Tuolumne the glaciers were in 
some places several miles wide and twelve hundred feet deep, 
and extended as much as forty miles down the valley. Gla- 
ciers likewise filled the Yosemite Valley on the Merced 
River. It is a mistake, however, according to Whitney, to 
suppose that the Yosemite was formed, or indeed greatly 
modified, by glacial action.* The vertical walls and the rect- 
angular recesses are such as to indicate the action of disrupt- 
ive rather than erosive agencies in their formation. 

The north-and-south valley between the Cascade Mount- 
ains and the Coast range, in the State of Washington, is about 
one hundred miles wide. The northern half of this is pene- 
trated by the innumerable channels and inlets of Puget 
Sound, which extends from Port Townsend south about 
eighty miles to the parallel of Mount Tacoma. The Olym- 
pian Mountains to the west rise to a height of about ten 
thousand feet, as does Mount Baker in the Cascade Range to 
the northeast. The shores and islands of Puget Sound have 
every appearance of being portions of a vast terminal, mo- 
raine. They rise from fifty to two hundred feet above tide, 
and present a mixture of that stratified and unstratified ma- 
terial characteristic of the terminal accumulations of a great 
glacier. No rock in place appears anywhere about the sound. 
Bowlders of light-colored granite and of volcanic rocks are 
indiscriminately scattered over the surface and imbedded in 
the soil. One of these bowlders, near Seattle, two hundred 
feet above the sound, measures twenty feet in diameter, and 
twelve feet out of ground. The channels of the sound and 


% “The Yosemite Guide-Book,” p. 83. See also the opinion of Mr. Russell 
given near the close of Chapter X. 


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182 THE ICE AGE IN NORTH AMERICA, 


by a series of ridges showing every mark of glacial origin. 
Not only is the surface of these ridges covered with bowl- 
ders, but wherever the streets have cut down into the soil 
they show, at the depth of a few feet, an unstratified deposit 
abounding in striated stones. Superimposed upon this ridge 
there is a thin stratified deposit of varying depth, but in- 
creasing in extent down the slope toward tide-water. 

At Port Townsend, on the Strait of Juan de Fuca, and 
forty miles northwest of Seattle, the coarsely stratified de- 
posit is much greater in extent. A noteworthy section of 
this I had the privilege of studying at Point Wilson, two 
miles and a half northwest of Port Townsend. Here, facing 


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Fie. 60.—Section of the deposit at Point Wilson described in the text, showing one hun- - 
dred and fifty feet in height, about one hundred of which is coarsely stratified, and 
contains layers of vegetable matter. Bowlders from till at the top have fallen down 
to form a talus at the water’s edge. 


the strait toward the north, is a perpendicular bluff from one 
hundred and fifty to two hundred feet in height, composed 


BOUNDARY OF THE, GLACIATED AREA. 183 


of material coarsely stratified throughout its lower portion, 
but capped at the summit by about forty feet of coarse, un- 
stratified material abounding in large striated bowlders, which, 
as they have been washed out by the erosion of the sea, are 
falling down to the foot of the bluff in immense numbers. 
Near the bottom of the bluff there are several strata of vege- 
tal deposits. One of these, two feet thick, consisted almost 
wholly of the fragments of the bark of the fir-trees which 
are now so characteristic of that region. Fragments of wood 
project from the freshly exposed bank in great abundance. 
The meaning of these facts will be more readily apparent 
after a study of the phenomena to the north of the strait. 
The Strait of Juan de Fuea is from fifteen to twenty 
miles in width, setting in from the Pacific Ocean and run- 
ning east and west. Its north shore, near Victoria, on Van- 
couver Island, is remarkably clear of glacial débris. The 
rocks, however, near Victoria, exhibit some of the most re- 
markable effects of glacial scoring and striation anywhere to 
be found. Immediately south of Victoria long parallel fur- 
rows rise from the shore of the inlet, and ascend the slope 
of the hill to the south to its summit, a hundred feet or more 
above the water-level. At the steamboat-landing, outside of 
the harbor, extensive surfaces freshly uncovered exhibit the 
moutonnée appearance of true glaciation, and, in addition to 
the finer and abundant scratching and strive, display numer- 
ous glacial furrows from six inches to two feet in depth, 
from twenty to thirty-two inches in width, and many feet 
in length. These grooves are finely polished and striated, 
resembling those with which geologists are familiar on the 
islands near the the western end of Lake Erie. Like the 
corresponding grooves on the islands of Lake Erie, some ot 
those near Victoria also form graceful curves, adjusting them- 
selves to the retreating face of the rock-wall. That the mo- 
tion of the ice at Victoria was to the south appears not only 
from the direction of the strie, but from the fact that the 
stoss sides of the glaciated rocky projections are toward the 
north. That they are due to glacial action, and not to ice- 


184 THE ICE AGE IN NORTH AMERICA. 


Fie. 61.—Glacial groovings near the landing at Victoria (see text). (From Photograph.) 


bergs, is evident both from their character and from their 
analogy to numerous phenomena farther to the north un- { 
questionably connected with true glaciers. 


BOUNDARY OF THE GLACIATED AREA. 185 


Speaking of Vancouver Island and the adjacent region, 
the Scotch geologist, Robert Brown, uses the following lan- 
guage: 

The chief rock 7m situ there is a dense, hard, feldspathic 
trap, and this is plowed in many places into furrows six to 
eight inches deep and from six to eighteen inches wide. The 
ice-action is also well shown in the sharp peaks of the erupted, 
intruded rocks, having been broken off and the surface smoothed 
and polished, as well as grooved and furrowed, by the ice-action 
on a sinking land, giving to the numerous promontories and 
outlying islands which here stud the coast the appearance of 
rounded bosses, between which the soil is found to be composed 
of sedimentary alluvial deposits, containing the dédris of ter- 
tiary and recent shelly beaches, which have, after a period of 
depression, been again elevated to form dry land, and to give 
the present aspect to the physical geography of Vancouver 
Island. 

The whole surface of the country is strewn with erratic 
bowlders. Great masses of sixty to one hundred tons in weight 
—chiefly of various igneous and crystalline as well as sedi- 
mentary rocks, sufficiently hard to bear transportation—are 
found scattered everywhere over the island from north to south, 
and through the region lying on the western slope of the Cas- 
cade Mountains.* 


The same observer thus speaks of the glacial phenomena 
on the mainland in the same vicinity: 


The following section is given to show the general character 
of the drift at Esquimault Harbor : 


Black sandy and peaty ground, with broken shells.....: :, 2 to6 feet. 
Yellowish sandy clay, with casts of shells (Cardium and 

Mya) and a few pebbles and bowlders.............. 6tos * 
Gravel of scratched pebbles resting on rock............. 2to3 “ 


The rocks are grooved and scratched at the junction ; the 
direction of the glacial markings is between north to south 
and north-northwest to south-southeast. In a well-sinking, at 


* “ American Journal of Science,” vol. c, 1870, pp. 320, 321. 


186 THE ICE AGE IN NORTH AMERICA. 


Esquimault Barracks (for the boundary commission), the lower 
gravel was reached at forty-two feet, after going through a 
sandy-blue clay without shells or bowlders. The section in the 
cliff between Albert Head and Esquimault is as follows : 


Blue drift clay, with bowlders; junction with rock 


NoOsiseen, £41. s See kin Jpikin SMe eee Oe 70 feet. 
Fine sand and gravel, passing upward into coarse 
quantzose!wravel eae: bi. 1. «haemo aoe ee 100 to 120 feet.* 


I saw at Seahome (near Bellingham Bay), in the cuttings 
made for a tramway, the finest instances of fluting and groov- 
ing—evidences of glacial action—that I have ever seen on this 
coast. They were ninety feet in length, rnnning north and 
south, according to the theory of Professor Agassiz. + 


Vancouver Island, which trends parallel with the shore 
of the continent northwest by southeast, is nearly three hun- 
dred miles in length and from fifty to seventy-five in breadth. 
In character it seems but a continuation of the Coast Range 
of mountains, with numerous peaks rising from four to seven 
thousand feet above the sea. The shore-line of the continent 
upon the northeastern side of the Strait of Georgia is formed 
by a continuation of the Cascade Range, with a general ele- 
vation of from three to eight thousand feet, and is penetrated 
in numerous places, to a distance of from twenty-five to 
seventy-five miles, by inlets or fiords some miles in width. 
Dr. George M. Dawson describes the glacial phenomena in 
Bute Inlet (which enters the Strait of Georgia about oppo- 
site the center of Vancouver Island, in latitude 50° 30’) in 
the following language: 

This chasm, forty miles. in length, and running into the 
center 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 six to eight thousand feet. It must have 
been one of the many tributaries of the great glacier of the 
Strait of Georgia, and accordingly shows evidence of powerfu: 


* “Quarterly Journal of London Geological Society,” 1860, p. 202. 
+ “American Journal of Science,” vol. c, pp. 322, 323. 


BOUNDARY OF THE GLACIATED AREA. 187 


ice-action. The islands about its mouth are roches moutonnées, 
polished and ground wherever the original surface has been 
preserved. In Sutil Passage, near its entrance, grooving ap- 
pears to run about south 30° west. 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, while rough toward 
the south. The mountain-side above Arran Passage shows 
smooth and glistening surfaces at least two thousand feet up 
its face ; and, in general, all the mountains surrounding the 
fiord present the appearance of having been heavily glaciated, 
with the exception of from one to two thousand feet of the 
highest peaks. The high summits are rugged and pointed, . 
and may either never have been covered by glacier-ice, or owe 
their different appearance to more prolonged weathering since 
its disappearance. In some places parallel flutings high up 
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 south 22° 
east ; but in every case the motion appears to have been di- 
rectly down the valley, and to have conformed to its changes 
in course. Glacier-ice may still be seen shining bluely from 
some of the higher valleys at the head of the inlet, and farther 
up the Howathco River there are many glaciers in lateral yal- 
leys, some of which descend almost to the river-level. 

Mr. James Richardson, who has had an opportunity of 
examining many of the inlets north of Vancouver Island, 
writes as follows :* ‘‘ Throughout the whole of the inlets and 
channels which were examined, wherever the surface of the 
rock is exposed, the ice-grooving and scratching are very con- 
spicuous, from mere scratches to channels often several feet 
in width, and from a few inches to as much as two or three 
feet in depth. Often they can be distinctly seen with the 
naked eye from the surface of the water to upward of three 
thousand feet above it on the sides of the mountains. They 


* “Report of Progress of the Geological Survey of Canada, 1874-75,” p. 8. 


188 THE ICE AGE IN NORTH AMERICA. 


run in more or less parallel lines, and are not always horizontal, 
but deviate slightly up or down.” * 


Mr. Robert Brown, whom we have sane quoted, gives 
the following additional information as to regions still far- 
ther north : 


I have not been in Alaska proper, but in 1866, in a visit to 
the Queen Charlotte Islands, lying some thirty or forty miles 
off the northern coast of British Columbia, close to the southern 
boundary of the former Territory, marks of the northern drift 
quite as marked as in Vancouver Island were found there. t 


As already indicated, the mountains on either side the 
Strait of Georgia, and northwestward to the head of Lynn 
Canal, about latitude 59° 20’, are snow-clad throughout the 
whole season. The shores are everywhere rocky and pre- 
cipitous, retaining in many places far up their sides glacial 
striz parallel with the direction of the numerous channels 
which thread their way through the Alexander Archipelago. 
I had opportunity at Loring, on the western shore of Revilla 
Gigedo Island, to examine minutely the striation on the shores 
and islands of Naha Bay. ‘There are now no glaciers coming 
down from the mountains of this island, but the shores and 
islands abound in well-preserved glacial striz running west 
by 18° north, corresponding to the direction of the local val- 
ley, down which a glacier came in former times, entering 
Behm’s Canal nearly at right angles to its course upon that 
side of the island. ‘This is about latitude 55° 40’. 

Upon proceeding one degree to the north, [ had oppor- 
tunity also to observe closely the striz at Fort Wrangel. 
Here, too, they show the influence of the continental eleva- 
tion to the east, and are moving outward in a westerly direc- 
tion toward the Duke of Clarence Strait. 

In Glacier Bay the evidence of the recent vast extension 
of the glaciers down the bay, and of the facility with which 


* “On the Superficial Geology of British Columbia,” in the “‘ Quarterly Jour. 
ual of the Geological Society,” vol. xxxiv, February, 1878, pp. 99, 100. 
+ “ American Journal of Science,” vol. c, p. 323. 


BOUNDARY OF THE GLACIATED AREA, 189 


glacial ice adjusts itself to the local topography, is, as already 
stated, of a most explicit character.* In addition to the evi- 
dence already mentioned, we may add that numerous islands 
project from the surface of the Muir Glacier, as from the 
waters of an archipelago, and that the summits of these bear 
every mark of having been freshly uncovered by the decreas- 
ing volume of ice. Also that below the mouth of the gla- 
cier numerous islands in the bay present exactly the same ap- 
pearance, except that they now project from water instead of 
ice. Their recent glaciation is indicated by every charaeter- 
istic sign. Willoughby Island, about the middle of the bay, 
is as much as a thousand feet above the water. Were the ice 
to retreat a few miles farther back from its present front, it 
would doubtless uncover an extension of the bay, with numer- 
ous islands similar to those now dotting its surface south of 
the glacier. Fresh glacial débrzs lingers on the flanks of the 
mountains on either side of the inlet, to a height of 2,000 
feet. The fact is also worth repeating and emphasizing that 
at 3,700 feet above tide striz were observed, on the east side 
of Muir Inlet, not pointing down the mountain, as might be 
expected, but parallel with the axis of the bay, showing, be- 
yond controversy, that the present glacier is but a remnant 
of an earlier ice-movement, similar in character and direction 
to the present, but of vastly greater dimensions, and which 
extended until it filled the whole bay to its mouth in Cross 
Sound, a distance of twenty-five miles. At Sitka, also, the 
rocks of the harbor are all freshly striated—the direction of 
the striz being toward the west—that is, toward the open sea. 
Glaciers still linger in the mountains at the head of the bay 
to the east of Sitka. 

The absence of glacial phenomena north of the range of 
mountains, which forms the southern boundary of Alaska, and 
over the adjacent plains of Northern Siberia, completely 
disproves the once current theory that the glacial period 
was characterized by a vast ice-cap extending in all directions 


* See above, p. 56 et seq. 


190 . THE ICE AGE IN NORTH AMERICA. 


from the pole. For, in both these regions, though the soil 
is frozen to a depth of several hundred feet, there are no indi- 
cations of the presence of moving ice. Stagnantice, however, 
in many places takes the place of ordinary rocks. The expedi- 
tion of Dawson to the Yukon in 1887 and that of Schwatka 
and Hayes around Mt. St. Elias in 1892 demonstrated an 
actual northward movement of ice. Dawson writes: 


In the Lewes and Pelly Valleys, traces of the movement of 
heavy glacier-ice in northward or northwestward directions, 
were observed in a number of cases, the grooving and furrow- 
ing being equally well marked at the water-level and across 
the summits of hills several hundred feet higher. ‘The facts 
are such as to lead to the belief that a more or less completely 
confluent glacier-mass moved in a general northwesterly direc- 
tion, from the mountainous districts south of the southern 
sources of the Yukon, toward the less elevated country which 
borders the lower river within the limits of Alaska. This ob- 
servaticn, taken in connection with the evidence of the former 
northward movement of glacier-ice in the arctic regions to the 
east of the Mackenzie, appears to have very important bear- 
ings on theories of general glaciation. ¢ 


From all these facts it seems evident that the supposition 
of a slight intensification of the present conditions so favor- 
able to the production of glaciers in southeastern Alaska, 
unravels the whole intricate web of glacial phenomena upon 
the western coast of North America. 

' The present formation of glaciers on the coast of south- 
eastern Alaska is favored not so much by the coolness of the 
climate as by the elevation of the mountains and the excess- 
ive amount of precipitation, which, as before stated, is not 
far from one hundred inches annually. There is no evidence 
that the elevation of the coast has materially changed in 
recent times. But it would require only a slight change in 
the amount of precipitation, or a slight diminution of tem- 


* “Science,’’ vol. xi, 1888, p. 186; ‘‘“Geological Magazine,”’ vol. ee 
p. 347 et seq. 
7 ‘‘Annual Report of the Geological Survey,’’ 1886, p. 56, R. 


BOUNDARY OF THE GLACIATED AREA. as | 


perature, to secure all the additional force required toextend 
the present glaciers of southeastern Alaska, British Columbia, 


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Fia. 62.—Map of area covered by the North American ice sheet of the Pleistocene epoch 
atits maximum extension, showing the approximate southern limit of glaciation, 
the three main centers of ice accumulation, and the driftless area within the glacia- 
ted region. It is now proven that the maximum advance from the Keewatin center 
preceded that from Labrador;since bowldery deposits from the northeast extend 
over those from the northwest throughout a large part of Indiana and Illinois and 
for quite a distanceinto Iowa. Lake Superior copper is found in the oldest deposits 
in Pennsylvania, while red jasper conglomerate bowlders from Lake Huron are 
found in the newer deposits west of the Mississippi a few miles from Keokuk. 

(From the United States Geological Survey.) 


and of the Cascade Range of State of Washington and Ore- 
gon, until they should gorge all the channels of the Alex- 


192 THE ICE AGE IN NORTH AMERICA. 


ander Archipelago, fill the space occupied by the Strait of 
Georgia between Vancouver Island and the mainland, and 
cover with ice the whole valley between Mount Tacoma and 
the Olympian Mountains, where now we find the vast mo- 
raine deposits of the islands and shores of Puget Sound. 

A simple calculation impresses one with a sense of the 
unstable equilibrium of the forces leading to the increase or 
diminution of a glacier. We estimated that 77,000,000,000 
cubic feet of ice annually pass through the gorge at the head 
of Muir Inlet, and that the area of the ice-field supplying 
this stream is about twelve hundred square miles. The total 
amount of ice entering the inlet, therefore, is only equivalent 
to about two feet of ice over the field of supply. If from 
any cause two feet more of ice should annually accumulate 
over this area, or two feet less should annually melt away, 
the amount of ice compelled to go through the gorge would 
be doubled, and this would doubtless fill up the whole inlet 
aud bay to the south. When we reflect that, according to 
Newcomb,* the average amount of ice which would be 
melted by the sun over the whole earth is something more 
than a hundred, feet a year, and that, therefore, a change in 
intensity amounting to only one fiftieth of that exhibited 
by the present meteorological forces would produce the re- 
sults just mentioned, we can readily believe that oscillations 
in such a great glacier may be frequent in occurrence and of 
great magnitude. 

Southward, in Oregon, the Willamette Valley was filled 
in a similar manner by an extension of the glaciers still lin- 
gering on the flanks of Mounts Hood and Shasta. The 
absence of drift on the southern shore of Vancouver Island 
seems to point to a termination of the southerly movement 
from Alaska in the Strait of Juan de Fuca, where perhaps 
the confluent streams turned westward, and sent off vast 
drift-laden icebergs to the sea. Mount Baker, immediately 
to the east of this point, upward of ten thousand feet high, — 


* “ Popular Astronomy,” p. 247. 


BOUNDARY OF THE GLACIATED AREA. 193 


and still preserving glaciers on its flanks, would have lent 
material aid in this seaward movement. The shores and 
islands about Puget Sound have the appearance of being the 
terminal deposits of confluent glaciers coming down from 
the flanks of Tacoma on the southeast, and from the lower 
portions of the Cascade Range farther north, joined by 
smaller glaciers from the Coast Range on the west. It is 
clear that the earlier glacial movements on the Pacific coast 
were local in character, and must be studied independently 
of those east of the Rocky Mountains, and can be understood 
only by reference to the glaciers which still linger at the head 
of all its numerous valleys, inlets, and fiords. In these the 
investigator has a vera causa ever before his eyes to guide 
his steps and to assist his imagination. 


COAPIER, VUE 
DEPTH OF THE ICE DURING THE GLACIAL PERIOD. 


THERE are two sources of information concerning the 
depth attained by the ice in North America during the Gla- 
cial period: First, we have direct evidence in the height of 
the mountains which have marks of glaciation upon their 
summits ; secondly, calculations can be made, with some 
approximation to truth, from the distance through which 
bowlders have been transported. 

Very conveniently for the glacialist, the mountains of 
New England and the Middle States serve the purpose of 
glaciometers, preserving upon their flanks and summits in- 
dubitable evidence of the great depth of the ancient ice-sheet 
over that portion of the country. 

It requires but a cursory examination to see that the 
highest point of Mount Desert Island, on the coast of Maine, 
was completely covered by the glacier, showing that at the 
very margin of the ocean the ice must have been consider- 
ably more than 1,500 feet deep. Even Mount Washington, 
in New Hampshire, was either wholly enveloped by the ice- 
current, or if a pinnacle projected above the glacier it could 
have been no more than 300 or 400 feet higher, Professor 
Hitchcock having found transported bowlders to within that 
distance of the summit. The ice-current passed over the 
Green Mountains where they are from 3,000 to 5,000 feet in 
height in a course diagonal to that of their general direction, 
showing that such a mountain-chain made scarcely more of a 
ripple in the moving mass than a sunken log would make in 
a shallow river. Farther south, Mounts Monadnock, Tom, 


DEPTH OF THE ICE DURING THE GLACIAL PERIOD. 195 


and Holyoke, the Berkshire Hills, and East and West Mount- 
ain, near New Haven, were also completely enveloped in ice. 
Between the Adirondacks and the Alleghanies the Mohawk 
Valley was filled nearly to the height of the Catskills, and the 
southern edge was pushed up in Monroe, Sullivan, Tioga, 
and Potter counties, Pa., to a height of 2,000 or 2,500 feet 
above the sea. 

In remarking upon the accompanying sections, Professor 
Lesley, who made them, says that while they do not satisfy 
him in several important particulars, such as the regularity 
of its surface, the location of possible crevasses, the descent 
into the plain, the distribution of bowlders, etc., they serve 
to give a correct generalized view—first, of the great thick- 
ness of the ice-sheet, by contrasting it with the sections of the 
solid rocks from the present surface down to the plane of 
sea-level ; second, to allow the reader to judge for himself of 
the extent of the eroding power at this point. We append 
Professor Lesley’s reasons for constructing the scale as he has: 


As to the first point, I have given to the surface of the ice 
a gentle slope southward, by making it 600 feet thick over the 
mountain, and 1,800 feet thick over Cherry Creek ; which 
slope, if* continued northward, would suffice to make the ice 
cover the highlands (2,000 feet above tide) farther north, as we 
know that it did. Thirty years ago Agassiz gave me his law of 
the necessary minimum thickness of a glacier for crossing a 
barrier. It was in a conversation immediately subsequent to 
his study of the strie on the top of Mount Desert, pointing 
from Mount Katahdin, and descending into the sea. He said 
that no glacier could cross a ridge unless its thickness at the 
summit of the ridge was at least one half the height of the 
ridge. By this rule he judged that the ice-sheet of Maine was 
750 feet thick over the top of Mount Desert ; and this would 
account for the great distance south of Mount Desert of the 
terminal moraine. 

This rule was obtained by Agassiz and Desor in their long 
residence on the glacier of the Aar, and was based on numerous 
observations of local Alpine glaciers where they were crevassed 


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DEPTH OF THE ICE DURING THE GLACIAL PERIOD. 197 . 


in surmounting barriers of rock. Whether it is a rule to hold 
good under quite different circumstances, in the case of conti- 
nental ice-sheets, or not, we have no means of knowing; but 
it is the only rule at ourcommand. I have applied-it to the 
case of the Kittatinny Mountain, and made the ice-sheet 600 
feet thick where it crossed the crest. It may have been any 
amount thicker for all we know. 

The two sections given in this plate were constructed by 
H. M. Chance, some years ago, after special topographical 
surveys and contour-line maps had been made by him at the 
Delaware, Lehigh, and Schuylkill Water-Gaps. They are pub- 
lished in Reports G* and D*, with the maps to which they 
belong. 

I have added to the north end of the upper section one of 
the transverse sections of Godfrey’s Ridge, south of Strouds- 
burg, which I made in 1840, in order to show the outcrops of 
Oriskany sandstone and Lower Helderberg limestone from 
which the bowlders were taken by the ice which now lie on the 
Kittatinny Mountain. 

Mr. Lewis remarks, on page 91, that ‘‘almost every block 
of limestone that was taken from the Helderberg Ridge in 
Cherry Valley can be traced to its destination” ; and on page 
88 he directs special attention to the large numbers and great 
sizes of them which were carried across Cherry Valley and left 
perched upon the top of Red Ridge overlooking Wolf Hollow ; 
and to one which he found on the very summit of the Kitta- 
tinny Mountain, at an elevation of 1,200 feet above the out- 
crop in Godfrey’s Ridge.* 


In the earlier reports upon the mountain-region of north- 
eastern Pennsylvania, it was concluded by Professors I. C. 
White and H. C. Lewis that the ice in that part of the State 
had not surmounted elevations more than 2,220 feet above 
tide. But Professor J. C. Branner, on re-examining the 
region in the summer of 1886, found distinct glacial marks 
upon the summit of Elk Mountain, in Susquehanna county, 
2,700 feet above tide; while the whole range of Lackawanna 


* “Second Geological Survey of Pennsylvania,” vol. Z, p. xiv. 


198 THE ICE AGE IN NORTH AMERICA, 


Mountains, northeast of the Susquehanna Gap at Pittston, 
showed distinct signs of glaciation on their highest summits, 
which are from 2,000 to 2,200 feet above tide. This would 
give a depth of 1,500 feet in the Susquehanna Valley in that 
neighborhood.* 

The most formal attempt to estimate from known data 
the depth of the ice near its ancient margin is that by Pro- 
fessor J. C. Smock, in a paper t before the American Asso- 
ciation for the Advancement of Science at Montreal. Pro- 
‘essor Smock finds definite evidence in northern New Jersey 
of a depth of only about seven hundred feet to the ice, 
though it is impossible to say that it was not more. For ex- 
ample, the highest points of Schooley’s Mountain table-land 
ronsist of moraine hills from twelve to thirteen hundred feet 
above tide, while the Musconetcong Valley to the west, which 
the ice had to fill before it surmounted the elevations indi- 
eated, is seven hundred feet lower, showing that the ice must 
at that point have been in the neighborhood of a thousand 
feet in thickness. Professor Smock was also the first one to 
ascertain that Pocono Mountain, in Monroe county, Pa., 
showed signs of glaciation up to a height of over two thou- 
sand feet. From the study of the glacial prenomena of that 
vegion, - Professor Smock correctly infers that “the inclination 
of the continental ice-sheet of the Glacial epoch was not uni- 
form. The rise was probably steep near the margin. ; 
Thus, near Feltville and Summit, the drift-covered Spring- 
field Mountain, which is about a mile north of the line, is 
nearly six hundred feet high. The high drift-hills near 
Mount Hope (960 feet) [also] show a great thickness near 
the margin. . . . Northward the angle of the slope dimin- 
ished, and ihe alee surface approximated to a great level 
plain. The distance between the high southwestern peaks 
of the Catskills and Pocono Knob in Pennsylvania is sixty 


3 “The Thickness of the Ice in Northeastern Pennsylvania during the Gla- 
cial Epoch, MBY dacs Branner, in the “ American Journal of Science,” vol. exxxii, 
1886, pp. 362-366. 

+ “ American Journal of Science,” > vol. cxxv, 1883, p. 339 ef seg. 


DEPTH OF THE ICE DURING THE GLACIAL PERIOD. 199 


miles. The difference in the elevation of the glacier could 
not have exceeded a thousand feet. In that direction the 
slope was less than on a meridian line from the Catskills 
southward.” 

Professor Dana estimates that the height of the ice 
“above the region of New Haven, in southern Connecticut, 
may have exceeded two thousand feet, and could hardly have 
been less than fifteen hundred.” 

So far the evidence is direct and positive, because the 
glacial marks are left upon the mountain-summits mentioned. 
How far still above these summits it rose is not so easily 
determined. From this amount of direct evidence it may 
also reasonably be inferred that the depth of the ice over the 
lake and prairie region of the West was equally great. If 
our interpretation of the facts implying the presence of an 
ice-sheet in North America is correct, we have also positive 
evidence of a great depth of ice over the central portion of 
British America between Hudson Bay and the Rocky Mount- 
ains. Here we find, according to Dawson, that bowlders 
from the Laurentian axis of the continent, which stretches 
from Lake Superior northward to the west of Hudson Bay, 
have been transported westward a distance of seven hundred 
miles, and left upon the flanks of the Rocky Mountains at 
an elevation of something over four thousand feet.* But 
nowhere does the Laurentian axis reach two thousand feet, 
its average elevation, according to Sir William Logan, being 
from fifteen to sixteen hundred feet. If these bowlders 
were, as we suppose, transported by glacial ice, then the ice 
must have accumulated over the Laurentian axis to a depth 
of 2,400 or 2,500 feet, and must have been several hundred 
feet deeper in the central part of the Red River Valley. 
Mr. R. G. McConnell, of the Canadian Survey, also, from 
more direct evidence, estimates + that, in the plains surround- 
ing the Cypress Hills (in the upper valley of the South 
Saskatchewan, in latitude 49° 30’, longitude 110°, and not 


* See p. 214. + See his “ Report on the Cypress Hills Wood Mountain.” 


200 THE ICE AGE IN NORTH AMERICA. | 


more than one hundred miles from the southwestern limit 
of the glaciated area in Montana), the continental glacier, or 
the glacial sea, according to which one of the theories of 
transportation is adopted, had a maximum depth of two 
thousand feet. This he determines by the height to which 
he found glacial deposits resting upon the Cypress Hills. It 
is the necessity of accounting for such an elevation of bowl- 
ders in glacier-ice which has made the Canadian geologists 
hesitate about accepting the glacial theory. It seemed to them 
at first more probable that there had been a depression of 
about four thousand feet in the Rocky Mountain region, and 
that these bowlders were transported from the Laurentian 
axis by floating ice. We think, however, that such facts as 
are illustrated in the diagram of Professor Lesley’s on page 
196, as well as other facts yet to be stated concerning the 
elevation of bowlders in ice, go far to remove the objections 
to the glacial theory urged by the Canadian geologists, and 
we therefore speak with considerable confidence of the great 
depth of the ice over the Laurentian axis. The glacial the- 
ory, moreover, as Dr. Dawson frankly and early admitted, 
relieves them of many difficulties in accounting for the 
noticeable absence of other indications of subsidence in the 
region under consideration. For example, there is, first, ac- 
cording to Dr. Dawson,* a complete absence of any marine 
animal remains in the drift over that region; and, secondly, 
“the yielding, scarcely solidified” sediments over this vast 
region bear slight evidence of any such great change in ele- 
vation. 

The great depth of the ice over the lake-region during 
the Glacial period is also evident from the second mode of 
calculation, namely, that based upon the distance over which 
bowlders are known to have been transported by the direct 
movement of the ice. The fluidity and plasticity of ice are so 
slight that, where we find it moving hundreds of miles over 
a level country, the thickness at the starting-point can scarcely 


* “Report on the Forty-ninth Parallel,” as above, pp. 216, 244, 260, ef al. 


DEPTH OF THE ICE DURING THE GLACIAL PERIOD. 901 


have been less than that indicated by the evidence in New 
England. Over southern Ontario and Michigan, and over 
the larger part of Wisconsin, Minnesota, northern Illinois, 
and Iowa, the ice must have been thousands of feet in depth, 
or it never could have pushed southward to the latitude of 
Cincinnati, Louisville, and St. Louis. | 

The uncertainties attending this mode of calculation are, 
however, very great, and it can be taken only for approxi- 
mate results. In the Alps the lowest mean slopes down 
which glaciers move are 23° to 3°, or about 250 feet to the 
mile. But, as Professor Dana notes,* the thickness of the 
ice there is not over 500 feet. Mathematicians are not able 
to deal successfully with the problems of friction in viscous 
bodies. How such a body will behave in greatly increased 
masses can be determined only by experiment. In Green- 
land, where the thickness of the ice more nearly approaches 
that of the ice-sheet formerly covering the northern part of 
the United States, Jensen found the slope of the Frederik- 
shaab Glacier to be 0° 49’, or about seventy-five feet a mile; 
while Helland found the slope of the Jakobshavn Glacier to 
be only 0° 26’, or about forty-five feet to the mile.t This 
latter slope of the surface of the continental glacier would, 
if continuous, make the thickness of the ice 10,000 feet over 
northern New England, and about 11,000 feet over Lake 
Erie, while the depth of the ice in this calculation over the 
region north of Lake Huron and Lake Superior, from which 
certain bowlders in Kentucky came, would be nearly 30,000 
feet, since the distance moved is 600 miles or more. 

Upon the supposition that the slope from the front to- 
ward the interior was but half a degree, Croll estimates that 
the depth of ice at the south pole, at the center of the Ant- 
arctic Continent, must be as much as twelve miles. This is 
on the supposition that the diameter of the continent is 2,800 
miles. The same rate of calculation would, according to 


- 


* “ American Journal of Science,” vol. exxvi, 1883, p. 348. 
+ “ Meddelelser om Grénland,” 1879, and ‘American Journal of Science,” 
vol. cxxiii, 1882, p. 364. } 


OD * THE ICE AGH IN NORTH AMERICA. 


Hitcheock,* require the ice of the Glacial period to be eight 
miles deep over the central part of Labrador; and, if the 
movement came from Greenland, the same slope of forty- 
five feet to the mile would reach, at that point, the astonish- 
ing depth of eighteen miles. ; | 

It is not necessary, however, to suppose a uniform slope 
to the center of so vast an ice field. If, however, we assume 
with Chamberlin and Salisbury,f that there was an actual 
movement of glacial ice of 1,600 miles from the Labradorian 
center to the southern part of Illinois, and of equal extent 
from the Keewatin center west of Hudson’s Bay to Topeka, 
Kansas, an average slope of but ten feet to the mile would give 
a depthof three miles at the centers. That the depth was as 
great as this, seems the more probable from the fact that the 
Keewatin center is low, and unless the elevation of that 
region was then much greater than it is now the movement 
must have been produced by the pressure caused by the simple 
accumulation of ice. Staggering to the imagination as these 
suppositions are, they seem to be inevitable inferences from > 
the established facts. A depth of three miles over the central 
portions of the glaciated area in North America is, therefore, 
by no means improbable. 


* ‘New Hampshire Geological Report,’’ vol. iii, pp. 320, 321. 
+t Geology, vol. iii, pp. 330, 357. 


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Mar sHowIve THE GLACIAL GEOLOGY OF THE 
UNITED STATES AND SOUTHERN CANADA. 


wa Southern Limit of the Ice-sheet and Drifé. 
pel Terminal Moraines. i 
By Mountain Areas of Zocal Glaciation 
wa Mountain Are cal & : 
Zo iftless Area of Wis MLS. 


'SCOMSIN. 
Modified Drift i valleys of Southward 
wainage trom the Icé- ; 


all. Sheet 
Ml Boundaries of Glacial Lakes. 


110 


sone 


es 


CHAPTER IX. 


TERMINAL MORAINES. 


Stvce the word moraine originally designates a consider- 
able accumulation of glacial débris, it has been found impos- 
sible to apply the term to the marginal deposits along the 
whole boundary; for, as was stated in the chapter treating 
of the subject, the glacial margin in the Mississippi Valley is 
not marked by such accumulations as characterize it east of 
the Alleghanies. The glacial deposits south of New England 
are, however, truly phenomenal in their extent, and can with 
perfect propriety be called terminal moraines. Why glacial 
débris should have accumulated to such an extent along that 
line it is impossible to tell with certainty ; but, recurring to 
the principles already presented, it would seem, not only that 
such an extensive terminal moraine indicates an abundance 
of easily disintegrated rock to the north offering itself for 
transportation in the line of the glacial movement, but that 
it also indicates that the ice-front remained for a long time 
stationary in the latitude of New York between Nantucket 
and the Delaware River. How much the proximity of the 
ocean may have had to do with the maintenance of this sta- 
tionary ice-front we may never fully determine; but, both: 
by its natural effect in eroding the advancing ice-column, 
and thus limiting its movement, and by its tendency to pro- 
vide moisture to the clouds which furnished the glacier of 
that whole region with its fresh supply of snow, the neigh- 
boring waters of the Atlantic would seem to be an adequate 
cause for the phenomenon. At any rate, in the hills of Cape 
Cod, of Nantucket, of Martha’s Vineyard, of the Elizabeth 


204 THE ICE AGE IN NORTH AMERICA. 


Islands, and of the south shore of Rhode Island, and in those 
forming the backbone of Long Island, we have one of the 
most remarkable true terminal moraines anywhere to be 
found in the world. 

Throughout their whole extent these terminal accumula- 
tions form a marked feature in the landscape, rising for a 
considerable portion of the distance from one hundred and 
fifty to three hundred feet above the general level of the 
country, and being dotted over with huge bowlders transport- 
ed a greater or less distance from the north. Kettle-holes 
and the small lakelets which they inclose are also constant 
features in the Jandscape. Throughout this whole extent, 
also, the moraines are flanked on the south by extensive de- 
posits of the ‘‘over-wash” gravel carried out by the water 
arising from the melting ice. The line of these moraines is, 
of course, at right angles to the direction of the ice-movement 
which terminated here. 

It is a remarkable confirmation of the theory already pre- 
sented in explanation of kettle-holes, that a study of those 
which mark the moraines of this region reveals a strong tend- 
ency in them to arrange themselves with their longer diameters 
parallel to the general trend of the moraine. Professor B. F. 
‘Koons* has taken the exact bearings of one hundred and six 
of these kettle-holes upon the island of Naushon and upon the | 
mainland from Wood’s Holl to Falmouth, and finds that the 
longer axis of eighty-two out of that number is approximately 
parallel to the direction of the moraine—that is, nearly at right 
angles to the direction of the ice-movement; and he is doubt- — 
less correct in his inference that “this is what we should ex- 
pect if the kettle-holes marked the localities where fragments 
of ice were broken off from the face of the glacier and buried, 
wholly or in part, by the earth and stones borne down by 
the ice-sheet.” By reference to the chapter upon the Muir 
Glacier, with the illustration there introduced, the reader may 


*“ American Journal of Science,” vol. cxxvii, 1884, p. 260 ef seg. ; vol. 
exxix, 1885, p. 480 e¢ seq. 


TERMINAL MORAINES. 


easily convince him- 
self of the correct- 
ness of this sugges- 
tion. “Some of 
these kettle - holes,” 
Professor Koons 
goes on to say, “are 
upon a truly grand 
scale ; for example, 
one which contains 
several smaller with- 
in the large depres- 
sion, and is like an 
immense amphithea- 
tre with the hills ris- 
ing upon every side 
of it. Its highest 
border is one hun- 
dred and fifty feet 
above the bottom and 
the outlet is forty 
feet above the small 
lake at its center ; 
and on the south side, 
near its border, but 
upon still higher 
ground, a bowlder 
stands projected 
against the southern 
sky like a huge sen- 
tinel as the observer 
views it from the 
bottom of this im- 
mense pit.”* As 


* “ American Journal of 
Science,” vol. exxvii, p. 262. 


Scale of 'miles;4 


E 
3 
5 
5 


Beale of roda 124 


205 


, 
n 


103, 105, 106 


2, 94, 95, 99, 100, 
em are about one hundred feet i 


, Massachusetts, by Professor B. F. 
, 86, 87, 89. 91, 9 


Nos. 66, 72, 76, 78, 82, 84 


103 are upward of fifty rods in diameter ; several of th 


er and shorter axes, 


iT 
WD Ane 


art of the Elizabeth Islands, and in the vicinity of Wood’s Holl 
Gy 


the lon 


The crosses show the direction ade 


are upward of twenty-five rods in diameter ; 9 


depth. 


Fia. 64.—Map of kettle-holes on the northern 
Koons. 


206 THE ICE AGE IN NORTH AMERICA. 


many as eight of those examined by Professor Koons were 
upward of eight hundred feet long and about half as wide; 
the rims from seventy-five to a hundred feet high. 


Fia. 65—Map of western New York, showing distribution of morainal deposits. (From 
U.S. Geological Survey.) 


West of the Hudson Valley, as we have already seen, it 
is difficult to trace a well-defined and continuous moraine 
along the extreme glacial boundary. Such a moraine is 
pretty well made out across New Jersey and a portion of the 
distance between the Delaware and Susquehanna Rivers in 
Pennsylvania; but, beyond, the country is mountainous, and 
through a considerable portion of the way difficult of ex-_ 
ploration. Through central New York, however, there are 
specially marked accumulations of glacial débris near the 
water-partings between the St. Lawrence and Mohawk Val- 
leys and that of the Susquehanna. President Chamberlin is 
inclined to correlate the accumulations just south of the 
“Finger Lakes” of that region + with the interior moraine 


+ ‘Preliminary Paper on the Terminal Moraine of the Second 
Glacial Epoch,”’ p. 3538. 


TERMINAL MORAINES. 207 


which we have described as running through Cape Cod, 
Elizabeth Islands, the southern portion of Rhode Island, and 
the northern part of Long Island, and also with those to be 
described more particularly hereafter as the Kettle Range, 
in Wisconsin. This interior line he would designate “ the ter- 
minal moraine of the second Glacial epoch.” But, in order to 
avoid the assumption of a distinct second Glacial epoch before 
conclusive proof is presented, the happy phrase of Professor 
Cook, of New Jersey, seems preferable, who would call the 
marked accumulations in the region to the north of the gla- 
cial limit “ moraines of retrocession.” Still, there is no great 
impropriety in calling them simply terminal moraines, since, 
wherever the ice-front paused for any length of time, a spe- 
eial accumulation of débris would take place, and would be 
terminal to the ice at that point. 

West of the Alleghanies, President Chamberlin deline- 
ates this moraine as extending in a series of lobes pointing to 
the south across the States of Ohio and Indiana, making one 
grand loop whose axis is nearly parallel with that of Lake 
Erie, returning with its western arm into eastern Michigan, 
between Saginaw Bay and the southern end of Lake Huron. 
He discovers five minor loops in this moraine in the axes of 
the following river valleys: (1) the Grand and Mahoning ; 
(2) the Sandusky and Scioto; (8) the Great Miami—all in 
Ohio; (4) the White, in Indiana; and (5) the Maumee and 
Wabash. But the accumulations called terminal in this re- 
gion are by no means comparable in extent with those south 
of New England or west of Lake Michigan, and the system 
is made out with some difficulty. 

In this portion of the territory there is another interior 
morainic belt of such interest that we pause to describe it 
more particularly. We refer to that of the Maumee Val- 
ley in Ohio, and can best describe it in the words of Mr. 
G. K. Gilbert, its original discoverer : 


The Maumee River occupies the axis of the broad, shallow 
valley which it helps to drain. This valley has no strongly 


208 THE ICE AGE IN NORTH AMERICA. 


marked limits. Eastward it is continuous with the trough of 
Lake Erie, and westward with the valley of the Wabash River. 
At the north, or more properly the northwest, its slopes merge, 
ata height of five hundred to six hundred feet (above Lake Erie), 
with those of the valley of Lake Michigan ; and its southern 
slopes, reaching a height of four hundred to five hundred feet, 
pass into those of the Ohio valley. With these low sides and a 
width of 125 miles, all its inclinations are exceedingly gentle, 
and the title of plain can be applied to it with no less propri- 
ety than that of valley. North of the Maumee the general de- 
scent is to the southeast, and south of that river to the north- 
east. With slight exceptions, the smaller streams follow and 
indicate these slopes, but all the larger tributaries of the Mau- 
mee, including the St. Joseph, St. Mary’s, and Auglaize Rivers, 
and Bean or Tiffin Creek, appear to be independent of them. 
The St. Joseph, for example, flows to the southwest through a 
country where every rivulet runs to the southeast. The entire 
region drained by it lies on its right bank, while from its left 
the drainage is toward Bean Creek, the divide between the two 
streams being everywhere within three or four miles of the St. 
Joseph. In like manner, the course of the St. Mary’s is west 
and north, and, while from its left bank the streamlets flow 
northeast into it, from its right they flow northeast into the 
Auglaize. These hydrographical peculiarities are so singular 
and striking as to have excited some attention and curiosity 
before the region was visited. Upon examination, there was 
found a continuous ridge, following the eastern banks of these 
rivers, and evidently determining their courses. Running 
somewhat obliquely across the slopes of the country, it turned 
aside all the small streams, and united them to form the Sit. 
Joseph and St. Mary’s. The height of this ridge is ordinarily 
from twenty-five to fifty feet, and its width at base from four 
to eight miles. Along the St. Joseph it is not distinguished 
from the adjacent country by its superficial characters. In 
common with that, it has a gently rolling surface, with a gray- 
elly clay soil, supporting a heavy growth of varied timber. 
Farther south, where it forms the north bank of the St. Mary’s 
River in Van Wert and Mercer counties. it is marked by such 
peculiarities as to divide it very sharply from the adjoining 


TERMINAL MORAINES, 209 


plains, which are nearly level, with a soil of fine clay, and cov- 
ered by a heavy growth of elm, beech, ash, maple, etc. The 
ridge, on the contrary, presents a confused series of conical 
hills, chiefly of clay, but showing some pebbles and small 
bowlders, and clothed by a forest-growth almost exclusively of 
oak. Probably the only essential point in this contrast is that 
of hill and plain, and out of this the others have grown. 
There is good reason to believe that the clay deposit (Erie clay) 
of the plain is continuous with that on the hills. Where its 
surface is level, it has retained its soluble salts and accumu- 
lated vegetable mold, so as to form a rich soil favorable to a 
varied vegetation; while from the steep hill-sides a great 
amount of soluble and fine material has been washed, so as to 
bring to the surface some of the pebbles everywhere imbedded 
in greater or less abundance, and the character of the vegeta- 
tion has been determined by that of the soil. 

I conceive that this ridge is the superficial representation 
of a terminal glacial moraine, that rests directly on the rock- 
bed, and is covered by a heavy sheet of Eric clay, a subsequent 
aqueous and iceberg deposit. Though this formation has an 
average depth along the upper St. Joseph of over one hundred 
feet, and on the upper St. Mary’: of fifty feet, it has not suf- 
ficed to conceal a moraine of such magnitude, but has so far 
conformed to its contour as to leave it still visible on the face 
of the country—doubtless in comparatively faint relief, but 
still so bold as to exert a marked influence on the hydrography 
of the valley.* 


When, a little later, we come to speak of glacial erosion, 
something more will be said confirmatory of this hypotheti- 
eal moraine of Mr. Gilbert, and of the varying movements of 
ice in the Lake Erie Valley at different stages of the Glacial 
epoch. We shall then see abundant reason for supposing 
that there was, for a considerable length of time about the 
close of the period, an independent movement of ice in the 
direction of the longer axis of the lake, and that this 


* “On the Surface Geology of the Maumee Valley,” in the ‘‘ Geological Sur- 
vey of Ohio,” vol. i, pp. 540-542. 


Fic. 66.—Western face of the kettle moraine, near Eagle, Waukesha County, Wisconsin. (From photograph by President T. C. Chamberlin, United 
States Geological Survey.) 


TERMINAL MORAINES. 211 


movement was directly toward the head of the Maumee 
River. 

The general system of interior moraines upon which we 
were remarking is pretty well exhibited about the eastern 
shore of Lake Michigan, forming a grand loop around that 
lake, and connecting with two subordinate loops around the 
head of Grand Traverse Bay and Saginaw Bay. But it is not 
until reaching the country west of Lake Michigan, in Wis- 
consin, that these glacial accumulations become again a very 
prominent feature of the landscape. Here they constitute 
the so-called Kettle Range, which forms a loop pointing to 
the southwest in the line of the longer axis of Green Bay. 
President Chamberlin has shown * that the ice-movement to 
the southward through Green Bay was in a measure inde- 
pendent of that through Lake Michigan; so that the eastern 
arm of the Kettle Range might more properly be called a 
médial moraine, to which the Lake Michigan Glacier and the 
Green Bay Glacier both contributed their deposits. This 
eastern arm runs about half-way between Fond du Lac and 
Sheboygan, and thence a little west of south, through Wash- 
ington and Waukesha counties, between Oconomowoc and 
Pewaukee, and through Eagle to Milton, between Janesville 
and Whitewater. Thence it swings northward, passing a few 
miles west of Madison, and, crossing an elbow of the Wiscon- 
sin River, incloses in its folds Devil’s Lake, near Baraboo, 
and thence on northward into the wilderness of northern 
Wisconsin, a little beyond the latitude of St. Paul, where it 
turns westward and with some deflection reaches the St. Croix 
River at Hudson, a few miles above its junction with the 
Mississippi. From this point it trends southward past Min- 
neapolis through southeastern Minnesota, inclosing in its 
folds Minnetonka and many other beautiful lakes in that 
portion of the State. From this point on, Mr. Upham has 
traced the moraine in an ox-bow-shaped extension, whose 


* “Preliminary Paper on the Terminal Moraine of the Second Glacial 
Fpoch,” p. 315, et seg. 


912 THE ICE AGE IN NORTH AMERICA. 


southern extremity is near Des Moines, Iowa, and whose 
western limb is the Coteau des Prairies of eastern Dakota. 

The conclusions of Mr. Upham and President Chamber- 
lin, concerning the movements of the ice over the region 
west of the lakes, are intensely interesting and seem amply 
warranted by the facts. It appears that in the northwest the 
ice advanced in four lines of motion pointing to a center a 
little below Dubuque, Iowa, though the columns did not all 
reach the point of their apparent destination: 1. One line 
of advance was down the depression of Green Bay, in Wis- 
consin. The moraine of this lobe constitutes what is called 
the Kettle Range of that State, and terminates a little west of 
Madison, on the eastern edge of the driftless region. 2. A 
second line of movement was down the valley of Kewanee 
Bay. This movement spent its force in northern Wisconsin, 
reaching the vicinity of Eau Claire. 3. The third move- 
ment was along the line of the main axis of the western end 
of Lake Superior, and extended across the Mississippi past 
Minneapolis, as far as Lake Minnetonka, and to a line run- 
ning northwest from this point for a hundred miles or more. 
4. The fourth movement was from the region of Lake Win- 
nipeg in the Red River Valley toward the south and south- 
east, meeting and opposing the ice-current from Lake Supe- 
rior, along a line from Stearns county, Minn., southeast by 
Lake Minnetonka to Crystal Lake in Dakota county. This 
is the movement which extended southward to the vicinity 
of Des Moines, Iowa, and whose western flank is the Coteau 
des Prairies. 

The line northwestward from Minneapolis, where these 
last two movements met, was an interesting battle-ground of 
the glacial forces. First, the Lake Superior Glacier pre- 
vailed, and pushed over the ground to its extreme limit, 
éven beyond the Mississippi. This boundary-line runs from 
Crystal Lake through Minnetonka, Wright, and Stearns 
counties, Minn. A little later, the Red River Glacier 
gained the ascendency, pushing the front of the Lake Supe- 
rior Glacier back into Wisconsin, east of the Mississippi. 


TERMINAL MORAINES. 213 


The reality of this battle of the glaciers, and of this alter- 
nate advance and retreat of the opposing forces, is shown by 
the succession of deposits. The lower part of the ground 
moraine is characterized by a reddish color, and by rock- 
fragments from the region of Lake Superior; while the 
upper portion, now upon the surface, is of a bluish color, 
containing bowlders and pebbles of limestone and of creta- 
ceous shale, and other material brought from the northwest, 
showing that victory was first to the Lake Superior Glacier, 
but finally to that of the Red River. 

The evidence of the junction of these two great ice- 
streams appears clearly enough upon the surface when sec- 
tions of country a little distance apart are considered. This, 
Dr. G. M. Dawson had observed as early as 1875, when he 
wrote about it thus : 


A line drawn northeast and southwest, nearly parallel with 
the northwestern shore of Lake Superior, but lying a short dis- 
tance back from it, and cutting the Northern Pacific Railway 
some miles west of Thomson, in this part of Minnesota, sepa- 
rates superficial deposits of different aspects. Northwest of 
this line the prevailing tint of the drift material is pale yellow- 
ish-gray, or drab ; southeast of it, reddish tints are almost 
universal, and become specially prominent on the northern 
part of the line of the Lake Superior and Mississippi Railway, 
and continue to St. Paul. The junction of these two varieties 
of drift can not, of course, be exactly defined, but is interest- 
ing as an indication of the direction of transport of material 
in this region ; the reddish matter being derived from the red 
rocks of the lake-shore.* 


Some other interesting things concerning the deposits of 
this region can better be said when we come to treat of gla- 
cial dams and lakes, and of the cause of the Glacial period. 

The surprising thing to a glacialist, upon a first visit to 


* “Report on the Forty-ninth Parallel,” p.213. See also “The Fresh-Water 
Glacial Drift of the Northwestern States,” p. 9, by Colonel Charles Whittlesey, 
who, it would seem, had noted the distinction as early as 1866. 


214 THE ICE AGE IN NORTH AMERICA. 


southeastern Dakota, is the extensiveness of the apparently 
level areas where the till comes to the surface. This impres- 
sion is heightened, probably, by the absence of forests, and 
would very likely be the same in portions of Ohio and 
Indiana were it not for the timber. James River Valley, in 
Dakota, is depressed in the center about five hundred feet 
below the edges, but it is, roughly speaking, seventy miles 
across, and therefore the slope does not strike the eye. So 
level is the country, that every special line of glacial accu- 
mulation is a prominent feature in the landscape, and the 
various halting-places of the ice in its retreat are readily dis- 
cerned. Evidently, a lobe of ice for a long time filled the 
James River Valley, running parallel with that which occu- 
pies the upper Minnesota Valley, and extended southward 
into lowa. The edges of these lobes thinned out along the 
north-and-south line which runs near the east margin of 
southern Dakota, and favored the accumulation of the mo- 
rainic hills, to which we have already referred as the Coteau 
des Prairies. Professor Todd and others speak of this as a 
series of terminal moraines formed along the sides of the re- 
entrant angle, between the two lobes, whose apex penetrated 
to the vicinity of the Sisseton Agency. Perhaps, however, 
it would facilitate a proper understanding of the subject to 
speak of the Coteau des Prairies as a medial moraine, like 
that east of Green Bay, toward which the glacial afm 
carried on the deeper portions of the ice of both the Minne- 
sota River and James River lobes, gravitated in contrary 
directions. But, whatever the name, ‘ebriate it is that, start- 
ing from the Sisseton Agency, different lines of glacial accu- 
mulations stretch southward at varying angles, the later 
accumulations forming the more obtuse angle. Coming up 
the valley of the James from Yankton, one crosses the old- 
est of these accumulations (the Altamont Moraine) in the 
neighborhood of the city itself, and the second (or Gary 
Moraine) in the neighborhood of Mitchell, sixty miles to the 
north, having run parallel with it, ee for about thirty 
miles. The third (or Antelope Marsan is cucaueee near 


TERMINAL MORAINES. 215 


Huron, about sixty miles north of Mitchell, and continues 
visible upon either side of the river about twenty miles dis- 
tant, as far up as Aberdeen. 

The western side of this lobe is characterized by corre- 
sponding lines of receding moraines, the outer of which is in 
the vicinity of the Missouri River and on its eastern side. 
Together, these form the Missouri coteau. Everywhere, in 
coming up from the river on the west to the plateau, which 
is in most places from four hundred to five hundred feet 
above the river, one encounters two or three bowlder-cov- 
ered terraces, the highest of which are at an elevation of 
from three hundred to four hundred feet. The moraines 
rise to a considerable height above the general level, and, as 
upon the eastern side, are everywhere marked features of the 
landscape. The streams entering the Missouri from the east 
are all of them short, none being more than forty miles in 
length. These streams are in all cases bordered by broad 
and elevated local terraces, the edges of which, where they 
overlook the immediate trough of the stream, are crowded 
with granitic bowlders. In some cases, as Professor Todd 
has shown, these valleys terminate abruptly in the water- 
parting, as if being the continuation of glacial streams from 
the east, which had originated upon the ice-lobe while it 
filled the James Valley. 

Professor Todd, to whom the exploration of this region 
was assigned, thus describes the Missouri coteau : 


This moraine consists of loops, convex usually toward the 
west and south, but in rare cases toward the northwest, as will 
be seen. hese loops connect at re-entrant angles pointing 
toward the northeast and east, which are usually sharp, and 
sometimes are extended into elongated ridges. The moraine 
varies in elevation with the region on which it rests. Its rela- 
tive height is usually great at the head of the re-entrant 
angles or interlobular moraines. These frequently stand out 
like great promontories, rising from one hundred and fifty to 
four hundred feet above the plain around them. At the bot- 
tom of a loop the moraine is apt to be slight or wanting, if on 


> 
‘ay auuahayd 


&%, vs 
(2) y 


“ey, 
he 


Vy) : Lung Lake 


00 


. 


fils: 


THE GREAT REE VA 
‘ 


SKETCH MAP | 
OF THE 


2 =) OL SNE 
MISSOURI COTEAU &™* S\ 
AND ITS 
MORAINES. 
By J. E. TODD, 
Asst. Geologist U. S. G. S. 


 Moraines 1, 2, 3 & 4. 
Contours 
Railroads 
Limit of Drift 
tecererecese Shore of Lake Dakota 


Fie 67. 


TERMINAL MORAINES. 217 


lower land; the flow of water from the ice probably having 
earried away the dédris as rapidly as it was pushed forward by 
the ice. On the other hand, in case the loop was pushed up 
an inclined plane, and the water did not find free escape, it 
(the loop) is well developed all around. The outer moraine in 
some places is very rough and stony; at other points it is a 
smooth, broad ridge, with few knobs, and covered with a deep, 
fertile soil.* 


Dr. G. M. Dawson early discovered the significance of 
this great Missouri coteau in its extension north of the 
United States boundary-line, and thus describes it: 


On approaching its base, which is always well defined at a 
distance, a gradual ascent is made, amounting, in a distance of 
twenty-five miles, to over 150 feet. The surface at the same 
time becomes more markedly undulating, as, on nearing Turtle 
Mountain from the east, till almost before one is aware of the 
change, the trail is winding among a confusion of abruptly 
rounded and tumultuous hills. They consist entirely of drift 
material ; and many of them seem to be formed almost alto- 
gether of bowlders and gravel, the finer matter having been to 
a great extent washed down into the hollows and basin-like 
valleys without outlets with which this district abounds. The . 
ridges and valleys have in general no very determined direc- 
tion, but a slight tendency to arrangement in north-and-south 
lines was observable in some places. 

The bowlders and gravel of the coteau are chiefly of Lau- 
rentian origin, with, however, a good deal of the usual white 
limestone and a slight admixture of the quartzite drift. The 
whole of the coteau belt is characterized by the absence of 
drainage valleys ; and, in consequence, its pools and lakes are 
often charged with salts, of which sulphates of soda and mag- 
nesia are the most abundant. The saline lakes frequently dry 
up completely toward the end of the summer, and present 
wide expanses of white efflorescent crystals, which contrast in 


* “ Proceedings of the American Association for the Advancement of Sci- 


ence,” vol. xxxiii, 1884, p. 383. 


Cuosmeg “A “D) “4X0} oY} Ul poq|iosep syjsodop jelous oY} Sumoys ‘voLWoWy YJION JO <O119}U! VY Jo avd Jo UOLJOes pue dey—“gg “BI a 


Pe paCeae Wh 
oe 


di (hell * ELIE LLL LL helene 


4 


LLL / 


NI 
ws 
ba 


Th 


<i 


DSR Rn SY 
ae ON 


EN. 
‘ 


TERMINAL MORAINES. 219. 


color with the crimson Salicornia with 
which they are often fringed. 


Taking the difference of level between 
the Jast Tertiary rocks seen near the east- 
ern base of the coteau and those first found 


on its western side, a distance of about sey- 
enty miles, we find a rise of six hundred 
feet. The slope of the surface of the under- 
lying rock is, therefore, assuming it to be 
uniform, but little more than four feet 
per mile. On and against this gently in- 
clined plane the immense drift deposits of 
the coteau hills are piled. 

The average elevation of the coteau above 
the sea, near the forty-ninth parallel, is 
about 2,000 feet ; and few of the hills rise 
more than one hundred feet above the gen- 
eral level. 

Between the southwestern side of the 
coteau belt and the Tertiary plateau is a 
very interesting region with characters of 
its own. Wide and deep valleys with sys- 
tems of tributary coulées have been cut in 
the soft rocks of the northern foot of the 
plateau, some of which have small streams 
still flowing in them fed by its drainage ; 
but for the most part they are dry, or oc- 
cupied by chains of small saline lakes which 
dry up early in the summer. Some large 
and deep saline lakes also exist which do 
: not disappear even late in the autumn. 
They have a winding, river-like form, and 
fill steep-sided valleys. These great old 
valleys have now no outlet; they are evi- 
dently of preglacial age, and have formed 
a part of the former sculpture of the coun- 
try. The heaping of the great mass of 
débris of the coteau against the foot of the 
Tertiary plateau has blocked them up and 


en S 

, a ld i Ac — aS 

p i , Pir 
ret Tm ; 

b Races = ! | 

a 7 Mode Ld ph Ah a= RO 


a 
rey 
=) 


Long. 1049 W. (From the northeast, distant about four miles.) 


(G. W.. Dawson.) 


-. Fre. 69.—The Missouri coteau, forming the edge of the Third Prairie. 


i ‘ 
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F {I a 
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4 " 
Site i 
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A 7 ‘ P 
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Fi ! 
Hoe Eat) ie 
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220 THE ICE AGE IN NORTH AMERICA. 


prevented the waters finding their way northward as before ; 
and, since glacial times, the rainfall of the district has never 
been sufficiently great, in proportion to the evaporation, to 
enable the streams to cut through the barrier thus formed. 
The existence of these old valleys, and the arrangement of the 
drift deposits with regard to them, throw important light on 
the former history of the plains. ; 

Northward, the coteau ceases to be identified with the Ter- 
tiary plateau, and rests on a slope of cretaceous rocks. It can 
be followed by Palliser’s and Hector’s descriptions of the coun- 
try to the elbow of the South Saskatchewan, and thence in a 
line nearly due north through the Eagle and Thickwood Hills ; 
beyond the North Saskatchewan, however, it appears to be- 
come more broken and less definite. In Dr. Hector’s descrip- 
tion of certain great valleys without outlet in this northern 
- region, I believe I can recognize there, too, the existence of 
old blorked-up river-courses similar to those just described. 

South of the forty-ninth parallel the continuation of the 
belt of drift material can also be traced. It runs southeast- 
ward, characterizing the high ground between the tributaries 
of the Missouri and the Red River, which has already been 
noticed in connection with the water-shed of the continent ; 
but, wanting the backing of the lignite Tertiary plateau, it 
appears to become more diffuse, and spread more widely over 
the country. That the drift deposits do not form the high 
ground of the water-shed, but are merely piled upon it, is evi- 
dent, as cretaceous rocks are frequently seen in its neighbor- 
hood at no great depth... . 

In the coteau, then, we have a natural feature of the first 
magnitude—a mass of glacial débris and traveled blocks with 
an average breadth of perhaps thirty to forty miles, and ex- 
tending diagonally across the central region of the continent 
for a distance of about eight hundred miles.* 


To one familiar with the literature of the subject, it 
would seem that Dr. Dawson’s sagacity in thus early dis- 


* “Quarterly Journal of the Geological Society,” vol. xxxi (November, 
1875), pp. 614-616. The facts are more fully stated in his governmental “ Re- 
port on the Forty-ninth Parallel.” 


TERMINAL MORAINES. 221 


cerning the great significance of the Missouri coteau has not 
received from glacial writers all the recognition it fairly 
deserves. But here we have, as in so many other instances, 
fresh illustration of the fact that the minds of sagacious 
investigators run in the same channel. Noteworthy in- 
ventions and discoveries are not often due to the work of 
single individuals. From the references already given, it 
would appear that Dr. Dawson’s surmise as to the signifi- 
eance of the Missouri coteau, President Chamberlin’s theory 
as to the meaning of the Kettle Range, Professor Cook’s 
delineation of the moraine across New Jersey, and Clar- 
ence King’s iaterpretation of the glacial accumulations on 
the south shore of Massachusetts were, in the minds of 
the authors, nearly contemporaneous and of independent 
origin. 

The subject of this chapter will not be complete without 
speaking of those later and more local moraines which were 
formed when the ice had withdrawn itself from the country 
in general, but still lingered everywhere in the mountains. 
Such moraines are numerous in all the valleys of the White 
Mountains. Professor Agassiz * describes no less than fifteen 
terminal moraines of small size crossing the valley of the 
Ammonoosue, a short distance below Bethlehem. Similar 
moraines exist in the valley leading down the Saco near 
Bartlett, and in the White Mountain branches of the Andros- 
coggin, as well as in the valleys leading to the vicinity of 
Center Harbor, on Lake Winnepesaukee. The principal local 
moraine of the Androscoggin is near the State line between 
Shelburne, N. H., and Gilead, Me. This has been described 
by Professor Stone and others.+ Other interesting moraines 
described by Professor Stone in Maine are located at Read- 
field Village, and at Swan Island in the Kennebec Valley, 
and at Sabbattusville, Machias, and Waldoboro. 

Among the innumerable instances of local moraines on 


* “ Geology of New Hampshire,” vol. iii, pp. 236-238. 
+ “American Journal of Science,” vol. exxxiii, 1887, p. 379. 


299 THE ICE AGE IN NORTH AMERICA. 


the Pacific slope, the following, described by Mr. I. C. Rus- 


sell, may serve as specimens: 


If one proceeds up the cafion [of Leevining River, Mono 
county, California], he will cross five or six small terminal mo- 
raines which traverse from side to side the broad trench left 
by the ancient glacier. These are seldom more than fifteen or 
twenty feet high, and are separated by grassy meadows. The 
creek was formerly dammed by these moraines and forced to 
expand so as to form small lakes; but these have long since 
been drained by the cutting of channels through the obstruc- 
tions.* 


Other instances have been already mentioned in describ- 
ing the glaciated boundary in Colorado, southern California, 
Oregon, and the State of Washington. Moraines of retroces- 
sion characterize almost every mountain valley which was 
occupied by ice during the Glacial period. 

The distribution of till in North America has been the 
subject of an immense amount of investigation during the 
past few years, accounts of which will be found in the vari- 
ous scientific Journals and State reports. Most prominent of 
all are those carried on by Mr. Frank Leverett, Professor 
Geo. H. Stone, and Dr. Warren Upham of the United States 
Geological Survey, and embodied in the monographs on the 
“Glacial Formations and Drainage Features of the Erie and 
Ohio Basins,”’ ‘‘The Illinois Lobe,” ‘‘The Michigan Glacial 
Deposits” (by Leverett); “The History of Glacial Lake 
Agassiz’’ (by Upham); and the ‘‘Glacial Deposits of Maine”’ 
(by Stone). | 

From these it appears that there are no less than twelve 
moraines traceable across Ohio between Cincinnati and Lake 
Erie, all belonging to the last, or so-called Wisconsin Episode; 
these follow very irregular lines, and are not always easy of 
_ recognition. Evidently they are moraines of recession, indi- 


*“‘Quaternary History of Mono Valley, California,” p. 334. 


TERMINAL MORAINES. 223 


cating points where there was a marked pause in the retreat 
of the front, affording time for a considerable accumulation 
of material, and perhaps sometimes of a short advance. 
These well defined morainic deposits mark a movement from 
Labrador as a center, and over a considerable area overrode 
earlier deposits which had been laid down by the movement 
from the Keewatin center west of Hudson’s Bay. The Wis- 
consin moraines are well developed across New Jersey and 
Pennsylvania down to the line surveyed by Professor Cook 
and by Lewis and Wright asmarkedonourmap. Westof this 
the glaciated area in Ohio and Indiana was covered with Wis- 
consin drift down close to the southern border; while in [lli- 
nois it reached well down towards the center of thestate, and 
in Iowa projected in a well defined loop as far as Des Moines, 
and in the Dakotas extended to the Missouri River. 

An earlier movement from the same centeris denominated 
the Illinoisan. This projected beyond the Wisconsin deposits 
over nearly all the western portion of Illinois, and crossed the 
Mississippi River for a short distance in the neighborhood of 
Burlington, compelling the river to flow for a short period in 
a new channel that can be traced from Clinton to Lee County, 
Iowa. Jaspar conglomerate bowlders from north of Lake 
Huron are found, with more or less frequency, over the whole 
region covered by the Wisconsin and Illinoisan deposits 
lying west of Pennsylvania and southeast of a line connecting 
Des Moines, Iowa and Green Bay, Wisconsin. 

Outside of the Illinoisan area thereis in Iowa astill earlier 
pretty well defined series of deposits called the Iowan. Mr. 
Leverett, however, does not now feel like recognizing these 
as distinct from the other deposits. But there is a very well 
defined line some distance outside the Wisconsin deposits, 
running across the state from east to west and nearly through 
the middle, separating an area which is covered by loess and 
one which is bare of loess, the loess evidently having been 
derived from the ice of the northern portion as it was swept 


224 THE ICE AGE IN NORTH AMERICA. 


off by the melting waters. But of this we will speak more 
particularly when treating of the loess. 

Still outside of the Iowan and the Illinoisan deposits cna 
is a vast area in Southern Iowa, Northern Missouri, and — 
Eastern Nebraska and Kansas, which is covered with a still 
older till, denominated Kansan. This till. is much more 
thoroughly oxidized than the other, and is spread more evenly 
over the surface with an entire absence of moraines. Still 
farther east (in Illinois, Indiana, Ohio, Pennsylvania, and New 
Jersey) there is also frequently found an attenuated border 
of glacial material which is correlated with the Kansan, from 
its having many of the same characteristics. It is more 
completely oxidized, more evenly spread over the area, and 
is devoid of moraines. It now seems clear that this Kansan 
till is the result of a movement of ice which preceded those 
which deposited the other sheets of till and, moving east- 
ward covered a large part of the field which is now enveloped 
with Iowan, Illinoisan and Wisconsin deposits. The extent 
of this eastward movement is not generally appreciated. But 
Professor E. H. Williams found Lake Superior copper firmly 
imbedded in ‘‘Kansan till,” forty feet below the surface, 
at East Warren, Pennsylvania, several hundred miles east of 
the source of supply. 

A still earlier glacial deposit has been recognized by the 
geologists of Iowa at Afton near the southern line of the 
State, and hence called the Aftonian Episode. This is recog- 
nized both by its position underneath the Kansan till and 
by its excessive oxidization. But, owing to its position it 
does not offer itself to inspection in many places, and even 
where it is visible its true age is a matter of speculation. 

The earliest of all drift sheets is thought to have been 
recognized by Dr. George M. Dawson in the Province of 
Alberta, east of the Rocky Mountains, in Southern Canada, 
‘while Professor Calvin has discovered what he thinks is a 
Sub-Aftonian till in Iowa, which may correspond to that 
described by Dr. Dawson. 


TERMINAL MORAINES. 225 


The main evidence of the age of these deposits will come 
up for discussion when we consider the date of the glacial 
period in general and of its various episodes. (See chapter XX, 
pp. 580-592). | 

But it will be in place to give expression at this point to 
some cautions against premature judgments respecting the 
evidence. It is important to keep in mind (1) the fact that 
there is no valid objection to the supposition that geological 
changes proceed much more rapidly at some periods than at 
others. Indeed it is a fundamental doctrine of evolution 
that cumulative strains in the earth’s crust may go on un- 
noticed for an indefinite period until the limit of resistance 
is reached, when there will be a rapid readjustment which 
may well deserve the name of catastrophe. Preglacial 
elevation proceeded all through the latter portion of the 
Tertiary Period until the snows of the Glacial Period pro- 
duced the ice age, when the very weight of the ice facilitated 
the subsequent depression and the rapid return to the ocean 
of the water that had been locked up in the continental 
glaciers. In this accumulation of ice over the northern 
hemisphere and its subsequent return to the ocean there is 
brought to light a force of such incalculable power affecting 
the elevation and depression of the land that the effects are 
entirely abnormal to our present experience. We cannot 
reason back from the rate of present changes to that of 
the Glacial Period. | 

(2) Again, we are never at liberty to lose sight of the fact 
that a long period of disintegration of the rocks over the gla- 
ciated region preceeded the ice age. The rocks over that 
region were then rotted to a great depth as they are now in 
the region south of the ice limit. This furnished an immense 
amount of oxidized material for the first grist of the glacial 
mill, and that was spread widely over the southern margin 
of the glaciated area. 


CHAPTER X. 
GLACIAL EROSION AND TRANSPORTATION. 


Tue extent of glacial erosion is a hotly contested question. 
One class of writers has gone to the extreme of attributing 
almost all the erosion of the higher latitudes to glacial action, 


Vip 


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Fie. 70.—Canon of the Colorado. Stream-erosion in a dry climate. (Newberry.) 
while another class has scarcely allowed any eroding power 


to glacial ice, in comparison with that of running water. 
In considering the relative importance of these agencies, 


Ce lage 


4 
f F , 


‘BMOT ‘AYO BMOT JO JSOMYPION *}J]IP WRALOT JO u[sIvUL JO TINOS soTTuUT OMY ‘ssooT Coop jo Aydesrsodoy—]J \ aLVv ig 


GLACIAL EROSION AND TRANSPORTATION. 227 


two elements enter into the problem: (1) the relative rate of 
action of the two forces, and (2) the relative length of time 
during which they have been in operation. 

As to time, it is evident that those have a great advantage 
in the argument who exalt the eroding power of running 
water. However slowly the drops may wear away the stone, 
ample amends are made in the length of the periods through 
which the action has continued. From the earliest ages of 
geological history running water has been at work counter- 
acting the effect of the forces which have elevated the con- 
tinents. River-channels are, in fact, more constant than 
mountain-chains. Everywhere and at all times the accumu- 


Fig. 71.—Embossed floor of an ancient glacier in the valley of the upper Arkansas River. 
(Hayden.) 


lating waters on a continental area seek and find the lowest 
paths to the sea. The sand and gravel which these running 
streams push along over their beds act as the teeth of a saw 


upon the rising mountain-summits, so that everywhere in 
mountain-regions of great age we find deep, transverse val- 


228 THE ICE AGE IN NORTH AMERICA. 


leys of erosion. Among the best-known examples in the 
country are those of the Mohawk and Hudson in New York; 
of the Delaware and Susquehanna in Pennsylvania; the 
Ohio and its tributaries on the western flanks of the Alle- 
ghanies ; the Mississippi and all its western branches, together 
with the Colorado upon the eastern flanks of the Rocky 
Mountains; and the Columbia, the Fraser, and the Stickeen 
Rivers, which penetrate in chasms of great depth the rock- 
bound shore of the Pacific. 

At the Delaware Water-Gap the river has sawn a vertical 
chasm more than a thousand feet deep directly across the 
hard strata of the Kittatinny Mountain. For fifty miles 
above Lock Haven, on the West Branch of the Susquehanna, 
the river occupies a narrow valley of erosion more than a 
thousand feet in depth. For nearly twelve hundred miles, 
as the water runs, the Ohio River, with its extension up the 
Alleghany, occupies a narrow, crooked valley, one mile or 
more in width and several hundred feet in depth, which it 
has worn through nearly parallel strata of lime and sandstone 
rock. The trough of the Mississippi from Cairo upward is 
similar. to that of the Ohio, except that it is two or three 
times as broad. The cafions of the Colorado, of the Yellow- 
stone, and of the Columbia, are of world-wide renown. The 
Colorado has worn a channel with nearly perpendicular sides 
three hundred miles long and from three to six thousand 
feet deep.* Such are some of the well-recognized results 
produced by the long-continued mechanical action of running 
water. 

But, aside from its mechanical action, water with the 
acids it contains is a most efficient chemical force, acting as a 
solvent upon various rocks. Every salt-spring and every 
spring of hard water in a limestone region is undermining 
the country from which it issues, and is engaged in dissolving 
the solid material and in transporting it in solution to lower 
levels. It is only a question of time when the chalk cliffs of 


* “Elements of Geology,” by Joseph Le Conte, pp. 15-17. 


GLACIAL EROSION AND TRANSPORTATION. 229 


England and the extensive lime formations of the Appala- 
chian region in America shall all be dissolved and carried in 
invisible solutions to the sea. The Mammoth Cave is but 
the remnant of larger, longer, and more numerous caverns 
which have honey-combed vast regions in Kentucky and in 
Tennessee. Many of the extensive valleys of that region are 
but the depressions formed by the falling in of the roofs of 
innumerable caverns. 

The rate of chemical erosion on limestone rocks is not 
easy to estimate. The most elaborate attempt of which I am 
aware is that of Professor A. L. Ewing in the Nittany Val- 
ley, of Huntingdon county, Pa.* 


This valley, which is known by different names, extends 
through a considerable-portion of the Appalachian region. It 
consists of the remains of a great anticlinal fold, which, had it 
not been eroded away, would form an immense mountain-like 
plateau over 20,000 feet above its present height. As it is, the 
floor of the valley is composed of the upturned edges of the 
lower Silurian limestone, eroded through a thickness of 6,000 
feet. The valley is flanked on either side by the overlying 
Medina sandstone, which forms monoclinical ridges from 600 
to 1,000 feet above its floor. 


From data carefully collected, Professor Ewing ascer- 
tains that the amount of solid matter annually carried out of 
the valley in chemical solution is equal to a layer of 5,1., of 
a metre in thickness. Hence, to lower the surface to the ex- 
tent of one metre by this process would require 29,173 
years—that is, it would take about 9,000 years to remove one 
foot from the surface. 


It is safe to assume that had the rocks of this region been 
similar to those of the bordering mountains in their nature and 
power to resist dynamical agencies, we should have in place of 
Nittany Valley a mild anticlinal plateau somewhat above the 


= See “ Proceedings of the American Association for the Advancement of 
Science,” vol. xxxiii, 1884, p. 494. The paper was published in the “Second 
Geological Survey of Pennsylvania, T?,” pp. 451-454. 


230 THE ICE AGH IN NORTH AMERICA. 


mountains in elevation—say 1,000 feet above the present 
height of the valley. 

The erosion in the valley, then, in excess of that along the 
mountains has been mainly chemical, and at least a thousand 
feet of limestone have been thus removed. A simple further 
deduction shows that, accordingly, Nittany Valley has been 
one million years in process of formation. 

The limestone erosion could not begin before the latter 
stages of the Mesozoic era, possibly not before the Cenozoic 
era, as sufficient time must have elapsed subsequent to the Car- 
boniferous age to erode all formations of the Paleozoic era 
above the Trenton limestone. One million years seems not in- . 
consistent with other estimates of geological time. 


In view of such facts the advocate of glacial erosion can 
not continue to maintain that ice is the chief agency in form- 
ing the contour of continental areas; but must grant that, 
by reason of the great length of time during which water 
has been about its work of corrosion and erosion, it is, with- 
out doubt, the most important instrument in diversifying the 
features of the earth’s surface. Still, however short, by com- 
parison, have been the periods of glacial action, no one can 
study a glacier or a glaciated region without being deeply 
impressed with the eroding and transporting power of mov- 
ing ice. To get a full conception of its erosive power, one 
must either get beneath it, or be able to calculate the force 
of its movement from what he knows of the nature of ice. 
Neither of these plans is altogether satisfactory, but each of 
them is to some extent feasible. 

From the nature of the elements at work it has qi**« 
generally been supposed that an advancing glacier would act 
like a plow or scraper, greatly disturbing and modifying the 
deposits over which it passed. But observation and a more 
careful consideration of the qualities of ice have materially 
modified these early impressions. From the fact that a 
stream of ice moves faster at the top than at the bottom, it 
follows that its action on underlying deposits is more like 
that of a drag than like that of a plow. The rocky frag- 


GLACIAL EROSION AND TRANSPORTATION. 231 


ments frozen into the bottom of the ice are not held there by 
a perfectly firm and unyielding grasp. The same bowlder 
which plows a furrow in the rock beneath it, plows a longer 
furrow in the ice which is moving over it. This is finely 
illustrated by some observations of Professor Niles. 

In a visit to the great Aletsch Glacier, in the summer of 
1878, Professor Niles had an excellent opportunity to exam- 
ine the under side of the ice of this glacier near its front. 
Here he observed numerous elongated ridges of rock over 
which the ice was flowing lengthwise, adjusting itself to all 
the corrugated surface. When the ice passed the lee end of 
the ridge it carried with it “the mold of the profile so per- 
fectly that for more than twenty feet the blue arch presented 
aseries of parallel furrows, like the flutings of a Doric 
column.” 


There was there at that time another highly interesting and 
instructive exhibition of glacial action. Within a few feet of 
the down-stream end of one of these elongated roches mouton- 
nées and upon its crest, there was a bowlder fully three feet in 
diameter, which evidently had been slowly moving along this 
ridge for some distance, probably from its upper end. There 
were two sides of this block of stone which were not incased in 
ice, viz., the lower one resting upon the rock, and the one 
facing down the glacier. From the lower end of the ridge of 
rock I looked at the bowlder through a tunnel of pure, blue 
ice, Which was continued as a deep furrow in the under sur- 
face of the glacier for fully thirty feet from its beginning. As 
this was produced by the ice moving over and beyond the 
bowlder, it was evident that the ice was moving more rapidly 
than the stone. I a. erward found other examples of the same 
kind, but none so favorably situated for a striking exhibition of 
this property of ice. it will be understood that these stones 
were sufficiently below the upper surface of the glacier to be 
removed from the effects of the ordinary changes of the tem- 
perature of the atmosphere. Although stones which are ex- 
posed to such changes may be frozen into the ice at the edges 
of the glacier, yet I believe these were so situated as to cor- 


232 THE ICE AGE IN NORTH AMERICA. 


rectly represent the conditions and movements of this at still 
greater depths. If this is correct, and I believe it is, it follows 
that such fragments of rock are not rigidly held in fixed posi- 
tions in the under surfaces of glaciers and carried irresistibly 
along at the same rate, but that the constantly melting ice 
actually flows over them, and that their motion is one of ex- 
treme slowness, even when compared with the motion of the 
glacier itself.* 


In a visit to the glaciers of Norway in 1886, Professor J. 
_ W. Spencer found abundant confirmation of Professor Niles’s 
inferences concerning the low eroding power of glaciers in 
certain conditions. He reports that the advancing Nor- 
- wegian glaciers “do not conform to the surfaces over which 
they pass, but are apt to arch over from rock to rock and 
point to point, especially as they are descending the ice-falls.” 
Professor Spencer continues: 


Beneath the glaciers of Fondal, Tunsbergdal, and Buardal, 
in the northern, north-central, and south-central snow-fields 
of Norway, as well as under other glaciers, | observed many 
stones inclosed in ice resting upon the rocks, to whose surfaces 
—sometimes flat, sometimes sloping steeply—they adhered by 
friction and by the pressure of the superincumbent weight. 
Although held in the ice on four sides with a force pushing 


downward, the viscosity of the ice, or the resistance of its — 


molecules in disengaging themselves from each other in order 
to flow, was less than that of the friction between the loose 
stones and the rock ; consequently, the ice flowed around and 
over the stones, leaving long grooves upon the under surfaces 
of the glacier. 

An example of the ability of the ice to flow like a plastic 
body was shown in a cavern four hundred feet higher than the 
end. of the glacier, where the temperature was 4° C., while that 
outside was 13° ©. Upon the débdris of the floor rested a 
rounded bowlder, whose longer diameter measured thirty inches. 
A tongue of ice, in size more than a cubic yard, was hanging 


* “ American Journal of Science,” vol. exvi, 1878, p. 366 ef seg. 


an 


GLACIAL EROSION AND TRANSPORTATION. 233 


from the roof and pressing against the stone. In place of push- 
ing the stone along or flowing around it, the lower layer of ice 
above the tongue had yielded, and was bent backward as easily 
and gracefully as if it had been a thin sheet of lead, instead of 
one of ice a foot thick. 

The insufficiency of glaciers to act as great erosive agents 
is further shown at Fondalen, where a mass of ice thirty or 
forty feet thick abuts against a somewhat steep ridge of a rock 
ten feet or less in height. In place of a stone-shod glacier 
sliding up and over the barrier, the lower part of the ice 
appears stationary, or else is moving around the barrier, while 
the upper strata bend and flow over the lower layers of ice.* 


The whole body of facts concerning a ground moraine 
speaks in like manner of the limited amount of disturbance, 
in certain conditions, which is produced by the ice as it 
moves over loose material. There ean be little doubt that, 
for a breadth of a hundred miles or more on the border of 
the glacial limit in North America, the ice advanced over 
the loose material (which is variously called ‘* bowlder-clay,” 
“till,” and “ground moraine ”) without greatly disturbing it 
as a body. Indeed, this great mass of firmly compacted, 
unassorted, and glaciated material would seem to have ac- 
cumulated by degrees—the moving ice, dragging along under 
it successive strata of the grist which it had ground from the 
surface of the rocks far to the north, where its action had 
been more vigorous and long continued. For another strik- 
ing illustration of the power of ice thus to move for a limited 
distance over loose material without disturbing it, one has 
but to refer to the description already given of the buried 
forest near the southwestern corner of the Muir Glacier, 
Alaska.t Here large trees in great numbers, which have 
been preserved for an indefinite period underneath the gla- 
cier, are now being uncovered, and appear standing upright 


* See “Glacial Erosion in Norway and in High Latitudes,” reprinted from 
“Proceedings of the Royal Society of Canada,” 1887; extracted from “ Ameri- 
can Naturalist,” vol. xxii, 1888, pp. 218, 221, 223. 

+ See p. 65. 

y 


234 THE ICE AGE IN NORTH AMERICA. 


with their branches intact upon them, and their roots im. 
bedded in the soil in which they grew. A stratum of this 
soil even consists of moss and leaves and cones which origi- 
nally formed a carpet over the forest floor. There can be no 
doubt that, after the accumulation of sand burying the forest, 
the glacier advanced for a great distance over it, attaining 
a thickness at that point of two or three thousand feet. 

A little reflection will show that the advance of a glacier 
upon a new field is analogous to that of the breakers in the 
ocean over shallow bottoms, though the impressiveness of the 
scene is disguised to the physical senses by the slowness of 
the movement in the case of a glacier, and by the counteract- 
ing effect of the heat which limits the advance of the ice-front. 
Where the ice-movement is upon dry land, the front is ordi- 
narily represented by a sloping field of ice covered with 
débris deposited from the melting surface near its terminus. 
For a long time investigators were puzzled by the fact that 
many bowlders are found some miles south of the line mark- 
ing the limit of glacial scratches upon the surfaces of the 
rocks. But, in the light of the vrevious suggestions, it is 
easy to see that for some distance back from the southern 
margin there could have been no movement at all at the 
bottom of the ice, so that bowlders upon the surface might 
be transferred, as upon the summit of a breaker, from some 
distance back of the front to some distance beyond the far- 
thest limit attained by the lower strata of moving ice. This 
narrow belt of glacial deposits bordering the limit indicated 
by other glacial signs constitutes what Professor Lewis and 
myself * agreed to call “the fringe ” of the terminal moraine. 
West of the Alleghanies this fringe is, as already shown, so 
wide as to assume commanding importance, and everywhere 
deserves more attention than we at first gave it. t | 

This characteristic of the movement of glacial ice is illus- 
trated by another phenomenon which has not been sufficiently 


* See ‘Second Geological Survey of Pennsylvania, Z,” pp. 45, 206 e¢ seg. 
+ Sec above, p. 149. 


— a 


GLACIAL EROSION AND TRANSPORTATION. 235 


weighed. In most of the text-books the formation of ice- 
bergs is represented to be by the pushing out of the ice into 
the water until the depth is such as to overcome its specific 
gravity, and lift a mass of ice up bodily and float it away. 
An inference from imperfect data by Dr. Kane has doubt- 
less done much to foster this idea. 


Regarded upon a large scale, I am satisfied that the iceberg 
is not disengaged by débdcle, as I once supposed. So far from 
falling into the sea, broken by its weight from the parent- 
glacier, it rises from the sea. ‘The process is at once gradual 
and comparatively quiet. The idea of icebergs being dis- 
charged, so universal among systematic writers and so recently 
admitted by myself, seems to me now at variance with the 
regulated and progressive action of Nature. Developed by 
such a process, the thousands of bergs which throng these seas 
should keep the air and water in perpetual commotion, one 
fearful succession of explosive detonations and propagated 
waves. But it is only the lesser masses falling into deep 
waters which could justify the popular opinion. The enor- 
mous masses of the great glacier are propelled, step by step 
and year by year, until, reaching water capable of supporting 
them, they are floated off, to be lost in the temperature of 
other regions.* 


Doubtless some icebergs are thus formed. But any tour- 
ist to Alaska may now satisfy himself that the ordinary 
method of the formation of an iceberg is by the breaking off 
of masses from the top as that portion of the ice is pushed 


on in advance of the lower strata. Still, as the fractures 


would not always reach to the bottom of a deep inlet, masses 
thus left below the water would eventually rise to the sur- 
face in case the front of the ice were retreating, so as to 
reinove the superincumbent weight from them. 

Coming now to consider the direct action of glacial ice 
in the transportation of solid material, we speak first of that 
carried upon the surface. Apparently there is scarcely any 


* “ Arctic Explorations,” vol. ii, p. 148. 


236 THE ICE AGE IN NORTH AMERICA. 


limit to the size of the fragments of rock which can be 
transported upon the back of a glacier. Nor would there 
seem to be any definable limit to the distance through which 
these masses of rock can thus be carried, except as there is a 
limit to the movement of the ice itself. In walkimg out on 
the smooth surface of the eastern part of the Muir Glacier, 
it was not uncommon to encounter, miles away from any 
mountains, cubical blocks of stone as much as twenty feet 
in their several dimensions, which, with countless others of 
smaller size, united to form a medial moraine. Slowly but 
surely these great bowlders have been brought to their pres- 
ent position, and slowly but as surely they are moving on to 
the front of the glacier, where, in due time, they will be 
deposited in the terminal moraine. 


The summary of facts published by President Hitch- 
cock many years ago may fitly serve as an introduction to 
the more detailed account to follow. In this, after remark- 
ing upon the great size of single bowlders, he illustrates the 
remark by the following examples : 


‘The block called Pierre 4 Bot, near Neufch4tel, contains © 
40,000 cubic feet. It has been transported from near Mar- 
tigny, more than sixty miles, across the great valley of Switz- 


GLACIAL EROSION AND TRANSPORTATION. 237 


erland. Professor Forbes describes another bowlder in the 
Alps, one hundred feet long and forty to fifty feet high ; also 
another, sixty-two feet in diameter, containing 244,000 cubic 
feet. In this country bowlders occur of equal dimensions. 
Thus, on Cape Ann and its vicinity, I have not unfrequently 
met with blocks of syenite not less than thirty feet in diame- 
ter ; and in the southeast part of Bradford (Mass.) I noticed 
one thirty feet square, which contains 27,000 cubic feet, and 
weighs not less than 2,310 tons. In the west part of Sand- 
wich, on Cape Cod, I have seen many bowlders of granitic 
gneiss twenty feet in diameter, which contain 8,000 cubic feet, 
and weigh as much as 680 tons. ‘Two sandstone bowlders of 
the same size lie a few rods distant from the meeting-house in 
Norton. A granite bowlder of equal dimensions lies about half 
a mile southeast of the meeting-house in Warwick ; and one of 
similar dimensions lies on the western slope of Hoosac Mountain, 
in the northeast part of Adams, at least one thousand feet above 
the valley over which it must have been transported. One of 
granite lies at the foot of the cliffs at Gay Head, on Martha’s 
Vineyard, which is ninety feet in circumference, and weighs 
1,447 tons. In Winchester, N. H., I recently met with a block 
of granite eighty-six feet in circumference. It is near the road 
leading to Richmond. I noticed another in Antrim, in that 
State, one hundred and fifty feet in horizontal circumference. 
Finally, at Fall River was a bowlder of conglomerate which 
originally weighed 5,400 tons, or 10,800,000 pounds.* 


A well-known bowlder in eastern Massachusetts, situated 
on a precipitous cliff in the southern part of the town of 
Peabody, goes by the name of Ship Rock. This is a gran- 
ite, and measures forty-five feet in length by twenty-two in 
height, and twenty-five in width. Its estimated weight is 
1,100 tons, and it is surrounded by many loose fragments 
weighing from fifty to seventy-five tons each. This rock 
has been purchased by the Essex Institute of Salem, and is 
carefully preserved from destruction.t 


* “Elementary Geology,” pp. 242, 243. 
+ See “ Journal of Essex County Natural History Society,” p. 120. 


238 THE ICE AGE IN NORTH AMERICA. 


In Essex County, Mass., numerous bowlders are traced 
to the White Mountain region more than one hundred miles 
distant. Plymouth Rock is a bowlder which accomplished 
its pilgrimage long before the voyage of the Mayflower. The 
backbone of Long Island largely consists of morainic material 
torn from the rocky hills of Rhode Island, Connecticut, 
and Massachusetts. The ‘‘Judge’s Cave”? on West Rock in 
New Haven, 365 feet above the sea, is a bowlder weighing 
a thousand tons. 


Fic. 73—Mohegan Rock. 


The largest bowlder yet described in New England is 
Mohegan Rock, in the town of Montville, New London 
County, Conn. Its dimensions, as reported to me by Mr. 
David A. Wells, are as follows: Length of eastern side, 54 
feet; southern side, 70; western side, 56; northern, 58; 
maximum height at least 60 feet. The weight has been 
estimated at 10,000 tons. 

Professor Crosby, however, says that a bowlder in Madi- 
son, N. H.,isstill larger than this. Itsdimensionsare30x40x 
75 which would give 96,000 cubic feet and an estimated weight 


nit lating ti Data eS 


GLACIAL EROSION AND TRANSPORTATION. 239 


of 8,000tons. But both these must give place to one men- 
tioned by Professor Edward Orton at Oregonia in Warren 
County, Ohio, where a mass of Clinton limestone. covering 
three-quarters of an acre, and twenty feet in thickness, has 
been moved by ice several miles and left with glacial deposits 
both above and belowit. These, however, aresmall compared 
with a mass of chalk described by Professor Holst near Malmo 
in southern Sweden which is three miles long, one thousand 
feet wide and from one hundred to two hundred feet in thick- 
ness, and which has been transported an indefinite distance 
by glacial ice and left on the surface of ordinary deposits of 
till. This mass is extensively quarried for commerical pur- 
poses. The quarries show that the chalk, especially in its 
upper portions is much disturbed, being broken into small 
fragments. Even the flint nodules are generally cracked, 
but the mass as a whole is well defined. A similar transported 
mass of chalk is reported from the eastern shore of England 
upon which a village had unwittingly been built. 

The train of bowlders in Richmond, Mass., near the sum- 
mit of the Berkshire Hills, was long ago described by Presi- 
dent Hitchcock and Sir Charles Lyell, and more recently 
and accurately by Mr. E. R. Benton.+ So much has been 
written about this train of bowlders, that it is worth while to 
give the results of this later investigation. The locality is in 
the towns of Lebanon, N. Y., and Richmond, Lenox, and 
Stockbridge, Mass., upon the western side of the Berkshire 
Hills. The trend of the rocky strata here is nearly northeast 
by southwest, and the elevation of summits of the ridges 
about sixteen hundred feet above tide, the valieys being 
about six hundred feet lower. Beginning on the Canaan and 
Lebanon ridge in New York, there is a line of peculiar bowl- 


* “Geology of New York,” Part IV, p. 165, e¢ seg. 

+ ‘“‘ American Journal of Science,” vol. exxvi, 1883, p. 347. 

t Lyell’s ‘‘ Antiquity of Man.” pp. 355-362; “ Bulletin of Museum of Com- 
parative Zoology at Harvard College,” Cambridge, Mass., vol. v, No. III, p. 41, 
with map. 


240 THE ICE AGE IN NORTH AMERICA. 


ders about four hundred feet wide, running continuously for 
nine miles southeast. These bowlders are composed of a 
chloritic schist, whose only outcrop is at Fry’s Hill, on the 
summit of the Lebanon range. West of the ridge there are 
none of these bowlders, but east of the knob the train is con- 
tinuous. Near the knob the size of the bowlders is larger 
than at a distance from it. Indeed, the size gradually dimin- 
ishes as the distance increases. The bowlders are distributed 
equally over the valleys intervening and over the flanks and 
summits of the ridges crossed. Besides the main continuous 
train of bowlders there are three others more or less continu- 
ous for a part of the way, and originating near the same 
knob. The diameter of the bowlders varies from thirty feet 
near their origin, to an average of two feet in Stockbridge, 
nine miles away. In the vicinity are other bowlders from a 
ledge whose outcrop was from four hundred to eight hun- 
dred feet lower than the hills upon which they are now 
resting. 

Sir Charles Lyell’s explanation of these remarkable trains 
of bowlders was that they were deposited when the region 
was depressed, so that oceanic currents carried icebergs over 
the summits of the intervening range, dropping their burdens 
along on the way. But it is surprising that the burdens of 
the icebergs should have been deposited so regularly, and still 
more surprising that icebergs should have raised bowlders 
and deposited them on surfaces eight hundred feet higher 
than the ledges from which they were torn. This is one of 
those numerous cases where the glacial hypothesis easily 
explains all the facts, and where it is difficult to see how 
any other hypothesis can do so. 

The only really peculiar thing about these celebrated trains 
of bowlders is that in their case the peak from which they 
are derived is isolated so that their origin can be readily 
traced. The prevailing rocks of this region are of such a 
nature that large bowlders could not readily be formed from 
them, whereas over most of the glaciated region the bowl- 
ders are so abundant and from such a variety of localities 


GLACIAL EROSION AND TRANSPORTATION. 241 


that it is not easy to single out a particular train. Careful 
attention, however, will doubtless resolve the whole mass of 
till into confluent trains of bowlders and more finely com- 
minuted material. | 

In New Jersey, according to Professor Cook, the bowl- 
ders are readily traced all along the morainic margin as be- 
longing to well-known outcrops of trap, blue limestone, and 
erystalline rocks to the northwest. Near Drakestown, in 
Morris county, there is a mass of blue limestone which had 
been worked for years as a quarry without suspecting that it 
was but a bowlder. ‘“ As exposed it measures thirty-six by 
thirty feet, and the quarrying has gone twenty feet in depth. 
Its vertical diameter is unknown. Around it are many 
gneissic bowlders and other drift materials.” * This mass is 
about one thousand feet above the sea-level, and its native 
place must have been some miles to the northwest. 

In Pennsylvania the distance from which the glacial ma- 
terial near the border of the glaciated region has been trans- 
ported becomes at once more evident, because of its unlike- 
ness to the local rocks. West of the Kittatinny Mountain, 
there are no erystalline rocks within the State. Nor are 
there any to the north nearer than the Adirondacks in New 
York, or the highlands in Canada. Yet granitic, gneissoid, 
and hornblendic bowlders abound all along the glaciated 
border, and are an important means of determining the 
glacial limit. In the valley between Kittatinny and Pocono 
Mountains, in Monroe county, and on the summit of the 
Pocono plateau, 2,000 feet above the sea, granitic bowlders 
from one to three feet in diameter are abundant, though 
mingled with great piles of local fragments. The granite 
must have been transported a distance of 250 miles at least, 
and carried over the summits of the Alleghanies, intervening 
toward the northwest, and across the valley of the Mohawk 
in New York. The northern tributaries of the West Branch 
of the Susquehanna, likewise, bring down into that stream 


* New Jersey Report for 1880. 


242 THE ICE AGE IN NORTH AMERICA, 


numerous granitic pebbles, showing that glacial deposits in 
Lycoming county contain material from the far north which 
has been carried bodily over the summit of the Alleghanies. 
On proceeding west, the granitic outcrops from which the ma- 
terial could come, gradually recede to the north, thus increas- 
ing the distance between such bowlders and their nearest 
known source. From Salamanca, N. Y., southwestward to 
Cincinnati the whole country is literally covered, down to 
the glacial limit, with granitic, gneissoid, and hornblendic 
bowlders. Near Salamanca such bowlders abound at eleva- 
tions not far from 1,900 feet above tide, and 700 feet above 
the Alleghany River. In Beaver county they are numerous 
on the hills down to within six or seven miles of the Ohio 
River, and several hundred feet above it. 

The following are some of the more specific facts drawn 
from my own notes: In Columbiana county, Ohio, a granitic 
bowlder was found measuring thirteen by eleven feet, and 
eight feet out of the ground. Others near by were noted, 
measuring eight and five feet in diameter. In the same 
vicinity the till contains finely striated fragments of local 
sandstone, showing direct glacial action on the local rocks. 
In Holmes county, also, tinely polished and striated pebbles 
of corniferous limestone occur, mingled with fragments of 
granite in the till. These must have been brought from the 
other side of the water-shed, in the vicinity of Lake Erie, 
100 miles distant. Near Lancaster, in Fairfield county, there 
is a granitic bowlder measuring eighteen feet by eleven, and 
six feet out of the ground. In Ross county, near Adelphi, 
Chillicothe, and Bainbridge, numerous granitic bowlders were 
found on the hills from 400 to 600 feet above the valleys, and 
about 1,200 feet above tide. A hornblendic bowlder five by 
three by two feet was noted 550 feet above Bainbridge. In 
Brown, Clermont, and Hamilton counties large granitic bow]- 
ders abound on the hills down to the very northern edge of the 
trough of the Ohio. Here, also, are to be found numerous 
bowlders of jasper conglomerate from the region north of 
Lake Huron or near the lower end of Lake Superior. The 


GLACIAL EROSION AND TRANSPORTATION. 243 


variegated pebbles of red jasper and of darker quartzites are 
a striking feature in the rocks of that northern region. The 
bowlders of this material found in the vicinity must have 
been transported nearly 600 miles. Several bowlders of this 
description were found in Boone county, Ky., a number of 
miles south of the Ohio River and between 500 and 600 
feet above it. Bowlders of this jasper conglomerate are very 
abundant in Michigan, are not infrequent in northern Ohio, 
and occur in various localities in southern Indiana—one 
being observed near Nashville, Brown county, Ind., near 
the highest land in the State (about 1,100 feet). Granitic 
and hornblendic bowlders are very abundant, also, as far 
south as Carbondale, Jackson county, IIl., below latitude 38°. 
The surface rocks are here distinctly striated, and the trans- 
portation must have been independent of any conceivable cur- 
rent of water. The distance from this point to the parent 
ledges to the north can not be less than 600 miles. 

All over northern Missouri, the whole of Iowa, and east- 
ern Dakota bowlders of large size are of frequent occurrence. 
In some places they completely cover the ground, especially 
in the lines of the great moraines. Even west of the Mis- 
souri, for thirty miles beyond Fort Yates, granitic bowlders 
are so abundant as to be prominent features in the landscape. 
Farther north in the same Territory and in Montana they are 
reported as sometimes so thick that a person can walk for 
long distances upon them without touching the ground. 

As has been already remarked, the glacial movement was 
everywhere at right angles to the glacial boundary. We 
should expect, therefore, to find that the bowlders along the 
western border of the glaciated area beyond the Missouri 
River had been transported from the northeast, and such is 
undoubtedly the fact. Im the recent excursion (in 1888) 
through nortliern Nebraska and central Dakota, already re- 
ferred to,* [ had abundant occasion to see evidences of this 
transportation. On the hills in Nebraska, from 500 to 600 


* See above, p. 174. 


244 THE ICE AGE IN NORTH AMERICA. 


feet above the Missouri River, extending in a southwest direc- 
tion from Yankton, Dakota, to the glacial border, a distance 
of about forty miles, transported bowlders of considerable 
size are abundant, and among them are numerous specimens 
of the so-called Sioux Falls quartzite, whose nearest outcrop 
is about forty miles to the northeast. 

All along upon the eastern side of the river in Dakota 
the glacial accumulations are on an enormous scale, and tlie 
transported bowlders without number; and on crossing the 
river at Fort Yates, about fifty miles south of Bismarck, 
granitic bowlders, in numerous instances from three to five 
feet in diameter, are found resting continuously over a belt 
of the highlands from 500 to 600 feet above the river, and 
extending about forty miles to the west, where they suddenly 
cease. There is granite in the Black Hills, 200 miles to the 
west, and from that source some pebbles have been brought 
down the Cheyenne River, which rises in that region. But 
with this exception, there are no granitic bowlders over the 
area between the Black Hills and this glacial border just 
mentioned. The source, therefore, of these bowlders on the 
west side of the Missouri River, extending from Bismarck 
to the Nebraska line, must lie somewhere to the northeast. 
Many of them might well enough have come from the vicin- 
ity of Lake Superior, a distance of 400 or 500 miles, though 
possibly some of them originated in more limited outcrops 
of granite in northern Minnesota. 

In British America, the transportation was outward from 
the Laurentian axis in every direction. From this axis bow]- 
ders in immense quantities were carried from 600 to 700 
miles westward and left on the fianks of the Rocky Mount- 
ains, from 2,000 to 3,000 feet above their source. 

In Dr. George M. Dawson’s report upon the extension of 
the Missouri coteau into the central region of North Amer- 
ica, he estimated that nearly ninety-eight per cent of this 
great accumulation between the Missouri and Saskatchewan 
Rivers was from the Laurentian axis, some hundreds of miles 
to the east; and that, upon the fringe beyond the coteau, 


GLACIAL HROSION AND TRANSPORTATION. 245 


where there is a mingling of material brought down from 
the Rocky Mountains, there is still for some: distance as 
much as forty-eight per cent of Laurentian material. 

Still farther north Dr. Dawson reports a movement of 
bowlders toward the north in the head-waters of the Yukon 
River, and in‘the northern portion of the continent east of 
Mackenzie River. 


For the arctic coast of the continent and the islands of the 
archipelago off it there is a considerable volume of evidence to 
show that the main direction of movement of erratics was 
northward. The most striking facts are those derived from 
Professor 8. Haughton’s appendix to McClintock’s ‘‘ Voyage,” 
where the occurrence is described of bowlders and pebbles from 
North Somerset, at localities 100 and 135 miles northeastward 
and northwestward from their supposed points of origin. Pro- 
fessor Haughton also states that the east side of King William’s | 
Land is strewn with bowlders of gneiss like that of Montreal 
Island, to the southward, and points out the general north- 
ward ice-moyement thus indicated, referring the carriage of 
the bowlders to floating ice of the Glacial period. 

The copper said to be picked up in large masses by the 
Eskimo, near Princes Royal Island, in Prince of Wales Strait, 
as well as on Prince of Wales Island,* has likewise, in all prob- 
ability, been derived from the copper-bearing rocks of the Cop- 
permine River region to the south, as this metal can scarcely 
be supposed to occur in place in the region of horizontal lime- 
stone where it is found. 

Dr. A. Armstrong, surgeon and naturalist to the Investi- 
gator, notes the occurrence of granitic and other crystalline 
rocks not only on the south shore of Baring Land, but also on 
the hills at some distance from the shore. These, from what 
is now known of the region, must be supposed to have come 
from the continental land to the southward. 

Dr. Bessells, again, remarks on the abundance of bowlders 
on the shore of Smith Sound in latitude 81° 30’, which are 
manifestly derived from known localities on the Greenland 


* De Rance, in “ Nature,” vol. xi, p. 492. 


246 | THE ICE AGE IN NORTH AMERICA. 


coast much farther southward, and adds, ‘‘ Drawing a con- 
clusion from such observations, it becomes evident that the 
main line of the drift, indicating the direction of its motion, 
runs from south to north.” * 

It may further be mentioned that Dr. R. Bell, of the Cana- 
dian Geological Survey, has found evidence of 4 northward or 
northeastward movement of glacier-ice in the northern part of 
Hudson Bay, with distinct indications of eastward glaciation 
in Hudson Strait.+ For the northern part of the great Mac- 
kenzie Valley we are as yet without any very definite infor- 
mation, but Sir J. Richardson notes that Laurentian bowlders 
are scattered westward over the nearly horizontal limestones of 
the district. 

Taken in conjunction with the facts for the more southern 
portion of the continent, already pretty well known, the ob- 
servations here outlined would appear to indicate a general 
, movement of ice outward, in all directions, from the great 
' Laurentian axis or plateau which extends from Labrador round 
the southern extremity of Hudson Bay to the Arctic Sea ; 
while a second, smaller, though still very important region of 
dispersion—the Cordilleran glacier-mass—occupied the Rocky 
Mountain region on the west, with the northern and southern 
limits before approximately stated. f 


Some facts already mentioned * have prepared the way for 
the discussion of that most puzzling and interesting problem 
of the upward transportation of earthy material in moving 
ice. The evidence upon this point is too abundant to be 
ignored. Professor Charles H. Hitehcock reports finding near 
the very summit of Mount Washington many small bowlders 
which must have been elevated a considerable portion of its en- 
tire height. One of these bowlders, weighing ninety pounds, 
is now deposited in the museum of Dartmouth College; and 


* “ Nature,”’ vol. ix. 

+ “‘ Annual Report of the Geological Survey,’ Canada, 1885, p. 14, D.D; 
and “‘ Report of Progress,” 1882-’84, p. 36, D. D. 

¢ See “Glaciation of British Columbia,” “Geological Magazine,” August, 
1888, pp. 348, 349. 

* See above, pp. 197, 240. 


GLACIAL EROSION AND TRANSPORTATION. 247 


another, of equal weight, may be found in the museum of the 
Boston Society of Natural History.* Professor Hitchcock 
writes me that while none of the very large bowlders in New 
Hampshire have been lifted up very much, it is safe to say 
that every New England mountain has bowlders on its sum- 
mit that have been brought there by the ice from at least as 
great a distance as from its immediate base. 

Describing a cut in till, forty feet deep, near the village 
of Queechee, Vt., on the Connecticut River, Professor 
Hitcheock says it is full of small-sized glaciated stones, 
cemented together by thick bowlder clay. Every stone is 
striated. There are great numbers of the Burlington (Vt.) 
red sandstone, “ which must have traveled from over the 
Green Mountains, over sixty miles, and have been raised 
over an acclivity of 3,000 feet altitude.” + 

Professor A. S. Packard, Jr., reports t that, at the height 
of about 4,000 feet above the sea, on Mount Katahdin, Me., 
“is a large mass of glacial moraine matter which has escaped 
denudation, and this incloses frequent rounded and polished 
bowlders of fossils of the same species of Silurian shells, and 
of the same silicious slates, as are found 7m situ a few miles 
northwest, on Lakes Webster and Telos. . . . The parent 
beds are but about twelve miles distant,” and, according to 
Mr. Upham, must be 3,000 feet lower. 

One of the clearest instances of the elevation of bowlders 
in the ice is the one already alluded to,* in the vicinity of 
the Delaware Water-Gap, on the summit of Kittatinny 
Mountain. This summit consists of Medina sandstone, and 
is about 1,500 feet above tide. Yet Professor Lewis found 
numerous bowlders of Helderberg limestone upon it, which 
he thinks must have come from Godfrey’s Ridge, in Cherry 
Valley, only a few miles to the north, and 1,200 feet lower. 


* For particulars concerning these bowlders, see Hitchcock, ‘New Hamp- 
shire Geological Report,” vol. iii, pp. 204, 207, 272. 

+ “New Hampshire Geological Report,” vol. iii, p. 262. 

t “Memoirs of the Boston Society of Natural History,” vol. i, p. 239. 

#* See cut above, p. 196. 


248 THE ICE AGE iN NORTH AMERICA 


Professor Lesley adds his testimony that in all northeastern 
Pennsylvania there is no other source of these bowlders but 
the one line of outcrop mentioned by Professor Lewis ; but, 
as it extends a hundred miles in a northeasterly direction, he 
is not sure that the particular locality from which these Hel- 
derberg bowlders came can be determined. Still, he is cer- 
tain that every limestone bowlder in northern New Jersey 
and eastern Pennsylvania has come from some point along 
this line of outcrop. Nowhere, however, does the Helder- 
berg limestone rise to an elevation of more than 1,000 feet 
above tide, while some of these bowlders are 1,500 feet 
above tide. emarking upon this, Professor Lesley says : 


The only problem of prime difficulty is, how the ice man- 
aged to lift the fragments from the outcrop in the valley to 
the crest of the Kittatinny Mountain—a problem which is re- 
peatedly presented for our “olution at various points where the 
terminal moraine crosses our mountain - ridges, and where 
blocks from a valley to the north are left perched on a mount- 
ain-top to the south. And the problem is not confined to the 
line of the moraine, but repeats itself at points many miles 
back of the moraine. Twenty years ago I found Catskill red 
sandstone fragments which had been carried up the north 
flank of the Towanda Mountain, in Bradford county, and been 
left on the edge of a swamp upon its flat summit of coal-meas- 
are sandstone ; and there is no Catskill country to the north 
-f a higher elevation from which the ice could have brought 
them with a descending gradient. 

Professor James Hall informs me that fragments from 
the Mohawk Valley have been carried up over the Hel- 
derberg Mountain to the south of it. precisely as the Ron- 
dout-Walkill bowlders have been carried over the Kittatimny 
Mountain. 

So, judging by the southeast strie, the gneiss and granite 
bowlders of western Pennsylvania must have been carried up 
from the level of Lake Erie (570 feet above tide) to elevations 
of 1,500 feet, along the line of the terminal moraine, 1,700 feet 
above tide at Lake Chautauqua, and even 2,150 feet above tide 


GLAVIAL EROSICUN AND TRANSPORTATION. 249 


in Little Valley, Cattaraugus county, N. Y.; unless we sup- 
pose that all the Canadian bowlders were borne upon the swr- 
face of the ice, which is clearly impossible. 

Bowlders of Alpine glaciers seem always to descend to their 
final resting-place, but we have innumerable proofs that the 
American ice-sheet managed, in some way, to carry bowlders 
from valleys up to mountain-tops, although the amount of 
elevation in many cases, if not in all cases, may be much less 
than we are inclined, on a first inspection of the facts, to take 
for granted. 

In the case of the Helderberg limestone bowlders men- 
tioned, found by Mr. Lewis on the crest of the Kittatinny 
Mountain, it is not necessary to suppose that it came from 
Godfrey’s Ridge, only three miles distant (north) in the valley 
below, 1,000 feet beneath its present position. Indeed, the 
direction of the scratches on the mountain-side make such a 
supposition incredible. Jt is plain that it must have traveled 
down the valiey of the Delaware, and may have come from the 
continuation of the range in the State of New York. The 
elevation of the surface gradually increases going east. The 
rise in the bed of the river for the first thirty-five miles, from 
the Delaware Water-Gap to Port Jervis, is about 200 feet. 
The rise from Port Jervis to the Rondout-Walkill divide, 
twenty miles, is 80 feet more. There the crest of the Helder- 
berg Ridge must be nearly 1,000 feet above tide. The crest of 
the Kittatinny Mountain where the block lies is about 1.500 
feet above tide. Therefore, if the block came these sixty-five 
miles, it has been carried up only 500 feet above its original 
situation. 

Still, it remains a problem by what sort of internal move- 
ment a stone held in the ice can ascend, however gentle may 
be the gradient upward. That internal movements take place 
in all glaciers, is made visible to the spectator by their spoon- 
shaped stratification, and by the different rates at which their 
upper, lower, middle, and lateral parts move along, as well as 
by the fact that they press forward over rock-barriers. But 
so general a statement has no scientific value when evoked to 
explain the actual translation of a bowlder up a mountain- 
slope. In fact, our knowledge of how such an operation was 


250 THE ICE AGE IN NORTH AMERICA. 


performed is as vague as possible, and demands the attention 
of hydraulic engineers. * 


Elsewhere + I have briefly considered the way in which 
this upward movement of bowlders imbedded in the glacial 
current might be produced. The subject is of so much in- 
terest and importance that it will be well to recur to it here. 

Asa result of the differential motion ina glacier in which 
each higher stratum of ice is moving slightly faster than that 
which is immediately below it, it follows that the inclosed 
bowlders are subjected to a differential strain, in which the 
upper portions are impelled forward with greater rapidity 
than the lower portions. The result of this ditterential strain 
upon the upper and lower portions of the bowlder, combined 
with the friction and viscosity of the ice, must produce a 
movement slightly upward as well as forward. The bowlder, 
being inelastic, or at any rate less elastic than the ice in 
which it is imbedded, must move as one mass, while each 
particle of ice moves in independence of all the others. 
Now, the portion of ice lying immediately in front of a 
bowlder, being protected from the differential pressure of 
the ice behind by the interference of the inelastic foreign 
object, offers more resistance in that direction than is pre- 
sented along a line leading diagonally upward across the lines 
of greater movement above. In other words, the frictional 
pressure of the moving ice upon the upper portion of a bowl- 
der is greater than that on its lower portions, and the greatest 
of all resistance is immediately in front. The line of least 
resistance is consequently always in a direction slightly up- 
ward. If, for example, the movement of the ice at the upper 
surface of a bowlder be represented by 100, and that at the 
lower portion of the bowlder by 99, then one one-hundredth 
of the force might be supposed to be expended in producing 
a diagonal upward movement. Thus we can conceive that 
fragments of rock were picked up from beneath the glacier, 


* See “Second Geological Survey of Pennsylvania, Z,” p. xxiii ef seq. 
+ “Glacial Boundary in Ohio, Indiana, and Kentucky,” p. 31. 


GLACIAL EROSION AND TRANSPORTATION. 251 


and that, after moving a sufficient distance, they appeared 
upon its surface ; and we can easily believe that many bowl- 
ders have thus been repeatedly transferred from beneath the 
ice to its surface, and thence projected by the more rapid 
superticial motion to the front to be reincorporated into the 
lower strata of the mass, and re-elevated to the surface again. 

Upon this subject Professor Lesley offers the following 
ingenious suggestions : 


When two equal solid bodies descending opposite slopes 
meet, they arrest and support each other. 

Imagine myriads of cannon-balls rolled from both sides to 
meet in the middle of a symmetrical valley. Those arriving 
first would remain ever afterward the lowest stratum ; those 
which followed would arrange themseives in higher and higher 
layers until the valley was full or the supply exhausted. No 
shifting of places would take place after each had found its 
lowest place. 

But suppose opposite descending quantities of pitch, or 
moist clay, through which cannon-balls were scattered, to meet 
along the middle line of a valley; the two advancing fronts 
would mash against each other, and thicken upward, the in- 
cluded cannon-balls rising vertically in the thickening mass, 
the thickening being in proportion to the height and weight 
and rigidity of the masses of clay pressing from the side slopes 
upon the middle line which had come to rest. 

By substituting plastic ice for moist clay, and rock-bowlders 
for cannon-balls, we get an idea of how the American ice-sheet 
may have carried up (diagonally) the masses which it tore 
from low-lying outcrops to higher levels, and even over mount- 
ain-crests. . .. 

A terminal moraine is often described as if it were merely 
the tumbled-off accumulation of the medial and lateral mo- 
raines which cover the surface and sides of a glacier. But the 
fact is, that a glacier is like a plum-pudding—full of scattered 
sand and stones from top to bottom and from side to side, all 
of whicli are delivered at its front end down the valley. The 
surface exhibition is made much stronger than it would other- 
wise be by the perpetual melting of the upper surface and sides 


252 THE ICE AGE IN NORTH AMERICA. 


of the glacier. This brings the plums in the pudding to the 
surface, and mixes them with the medial moraine blocks which 


Fie. 74.—Glaciated pebble from southern Indiana. Natural size. This was one of the 
graving tools of the glacier. The striz are parallel with the longer axis. 


have ridden down from the forks of the valley. A constant 
concentration of the débris of the whole glacier thus goes on 
at its surface in spite of the occasional loss of some of the stuff 
by dropping into crevasses, the blocks thus temporarily lost 
fejoining their fellows at the surface, if the glacier be long 


GLACIAL EROSION AND TRANSPORTATION. 253 


enough, lower down the valley, or issuing midway of its front 
end in the mass of the terminal moraine.* 


It is urged, both against the foregoing statement of facts 
and their theoretical explanation, that observations in Green- 


Fie. 75.—Reverse side of the same pebble. 


land are irreconcilable with them. For it seems to be ad- 
mitted that the surface of the great ice-cap of Greenland is 


* “Second Geological Survey of Pennsylvania, Z,” p. xxv ef seq. 


254 THE ICE AGH IN NORTH AMERICA. 


tree from bowlders, except in the lines of movement extend- 
ing from the nunataks. A sufficient reply to this objection 
is to say that a country so long subject to glacial movements 
as Greenland has been must already have had the looser frag- 
ments of rock, which can be incorporated into the ice, gath- 
ered up and removed to the front, so that now the floor of 
the whole continent is so smooth and bare of fragments that 
there is nothing left for the glacier to get hold of. But dur- 
ing the movement of the glacier over the northern part of 


the United States, everything favored the mode of trans- 


portation and elevation of bowlders as described above. 

As already shown,* the transportation of large bowlders, 
though impressive in view of the enormous masses moved, 
probably represents but an insignificant part of the work of 
erosion and transportation which took place during the Gla- 
cial period. Some would even regard the subglacial streams 
pouring out in front of every glacier, and surcharged with 
fine sediment, as the most important instruments of glacial 


transportation. How much of the glacial grist has been car- _ 


ried away by this process it is impossible to determine with 
accuracy. It will, however, be of some interest to learn the 
best attainable results. 


In 1864 Dolfus-Ausset measured the fine sediment carried 
out by the stream from below the Unter-Aar Glacier, finding 
132 grammes in a cubic metre of water. This corresponds to 
a yearly rubbing off of about 0°6 millimetre of rock from under 


all parts of the glacier’s basins, or an erosion of one metre in 


1,666 years—about two and a half times as much as water 
could do in the’same period. It is not determined how much 
of the sediment came from sand washed under the ice by side 
streams, but’ it shows that the glacier does a considerable 
amount of work (‘‘ Matériaux pour I’Etude des Glaciers,” 1864, 
vol. 1, p. 276).+¢ 


* See above, p. 136. 
+ Professor W. M. Davis, in “ Proceedings of the Boston Society of Natural 
History,” vol. xxii, 1882, p. 26. 


re 


a a a ean! 


dt 


{ 
ee eee eee 


a 


eA Sy a a Aa a A rl lay A wm eh aa as aaa 


deh? ret ag mo 


au 


GLACIAL EROSION AND TRANSPORTATION. 255 


M. E. Collomb has made some interesting calculations 
. . . based upon the observations of MM. Dolfus and Desor on 
the Aar Glacier in 1844 and 1854. These glacialists found 
that the amount of water discharged from this glacier between 
the 20th of July and 4th of August averaged 1,278,738 cubic 
metres daily—the minimum being 780,000 cubic metres, and 
the maximum 2,100,000 cubic metres. The area occupied by 
the glacier is estimated at fifty-two square kilometres. Now, 
supposing that the old glacier of the Rhone (the area of which 
M. Collomb estimated at 15,000 square kilometres, but which 
is actually under the truth) discharged its water at the same 
rate, it must have yielded a daily supply of 605,000.000 
cubic metres. But if it be true, as all the facts would lead us 
to believe, that in the summers of the Glacial period more heat 
was received directly from the sun, then the daily discharge 
from such a glacier must have been greatly in excess of that 
amount. : 

. . . MM. Dolfus and Desor found that a litre of water 
from the Aar Glacier contained 0°142 gramme of fine mud ; so 
that, according to Collomb’s estimate of the area and daily dis- 
charge of the ancient Rhone Glacier, the wate. escaping from 
the latter must in summer time have transported 86,000,000 
kilogrammes, or about 8,50¢ tons (English) per diem—an esti- 
mate which, considering the circumstances already referred to, . 
is probably much under the actual truth. 

According to Helland, the quantity of mud in the rivers 
that issue from the glaciers of Greenland is very variable, as 
may be seen from the table given by him, which is as follows : 

Grammes of 


mud in 1 cubic metre 
of water. 


River of the glacier of Jakobshavn...... July 9,1875.... 104 
rh M2 Alangordlek..... eo) OS. wha. Dare 
fs $s Lardlak occ). 32. Foil teri’. oth eae 
a ni Tuaparsnit,:.:Angust. 6,  “..:j..,.,6%8 
. - Umiatorfik...... Be DO oe Oe tee 75 
* " Assakake fi.°... ced Miter eee Be 
= sh Rangerdlugssuak “ 11, “ .... 278 


Similar observations by the same geologist on the water 
issuing from the snow and ice-field of Justedalsbraeen likewise 


256 THE ICE AGE IN NORTH AMERICA. 


showed that the quantity of mud varied in the different streams, 
and even in the same river. ‘The result of ten different obser- 
vations in the months of June and July gave a mean of 147°9 
grammes of mud in 1 cubic metre of water. (See ‘‘ Quarterly 
Journal of the Geological Society,” 1877, p. 157.) * 


Mr. J. E. Marr gives the following facts concerning the 
extent to which erosion is proceeding beneath some of the 
Greenland glaciers : 


The erosive power of an ice-sheet is well seen by a glance 
at the observations made upon the rivers which flow into the 
tiords of Nagsugtok and Isortok, and which have their origin 
at the ends of the tongues of ice which occupy the val- 
leys continuous with these fiords. The river from the first 
_ contained only 200 to 225 grammes of mud per cubic metre of 
water in the month of July ; while the second, in the month 
of June, inclosed 9,129 to 9,744 grammes. This is compared 
with the amount carried by the Aar where it emerges from 
the glacier: it there contains only 142 grammes. The great 
difference presented by the rivers which fall into the two fiords 
is attributed to the fact that the ice moves with much greater 
speed toward the fiord of Isortok than toward that of Nagsug- 
tok. It is calculated that the quantity of fine mud carried 
into the former of these fiords amounts to 4,062,000,000 kilo- 
grammes: per day. This mud is deposited in the interior of 
the fiord, which is filled up to such an extent in its upper por- 
tion that even flat-boats can not pass up it. + 


The amount of material carried to the sea by the subgla- 
cial streams during the continuance of the Glacial period 
in North America could not be estimated, even though we 
knew the rate of transportation, unless we had more definite 
ideas than we now have of the length of time during which 
glacial conditions prevailed. But if, as is probably the case, 
the deposits of loess in the valley of the Mississippi are of 


* Geikie’s ‘“ Prehistoric Europe,” pp. 231, 232. 
+ See “‘ Geological Magazine,” April, 1887, summarized in “ American Jour- 
nal of Science,” vol. exxxiv, 1887, p. 318. . 


GLACIAL EROSION AND TRANSPORTATION. 257 


glacial origin, these may at some time give us a partial clew 
to the length of the period. 

Another method of estimating the amount of glacial ero- 
sion is by calculating the extent of the deposits over the 
glaciated region. Professor Newberry has estimated that 
the area south and west of the Canadian highlands, covered 
with glacial débris, is not much less than 1,000,000 square 
miles, and that the depth of the deposit over this broad 
marginal area can not be less, on the average, than thirty 
feet, and is probably twice that amount.* Professor Ciaypole 
found, upon comparing the estimates independently made 
in different counties of Ohio, Indiana, and Illinois, that the 
average depth for these three States was sixty-two feet, and 


S L396 be 

7 ee, Se / 

Zs 
Fig. 76.—Ideal section showing how the till overlies the stratified rocks. 


for Ohio alone fifty-six feet.t Recent extended experi- 
ments in boring for gas in western Ohio and eastern Indi- 
ana tend greatly to increase the estimate of Professor Clay- 
pole. There are whole counties in southwestern Ohio so 
deeply covered with glacial débris, that few of the citizens 
have ever seen the underlying rock. In other counties, 
where the rock occasionally crops out at the surface, the ex- 
tensive spaces between are found to be valleys of immense 
depth, filled with the unstratified material of the ground 
moraine. In Professor Orton’s recent report on the subject, 
giving the depth in fifty-three of the counties of Ohio as 
determined by the borings in 122 wells, the average is found 
to be upward of 90 feet (93 feet +). In some of the wells 
the depth was truly phenomenal, as in St. Paris, Champaign 
county, where, in one well, rock was not reached short of 


* “School of Mines Quarterly,” January, 1885, p. 7. 
+ “Glacial Erosion,” by William. M. Davis, “ Proceedings of the Boston 


Society of Natural History,” vol. xxii, pp. 19-58. 


258 THE ICE AGE IN NORTH AMERICA. 


370 feet, and in another, 530 feet of till was penetrated, and 
the well abandoned before rock was reached. In Dayton, 
Montgomery county, the glacial deposit was found to be 247 
feet ; in Cridersville, Auglaize county, 300 feet; in N ew- 
ark, Licking county, 235 feet; in Lebanon, Warren county, 
256 feet; in Osborn, Greene county, 207 feet ; in Hamilton, 
Butler county, 214 feet. These are all, perhaps, in pre- 
glacial valleys. But the average in various counties is cer- 
tainly significant. In Auglaize county, six borings give an 
average of 141 feet; in Butler county, four borings, 116 
feet. 

With reference to the correctness of this representation, 
it should be remarked that borings prosecuted in this man- 
ner are more likely to give an underestimate than an over- 
estimate of the real facts; for, as is well known, it is much 


easier and less expensive to drill through the sedimentary . 
rocks than through deep deposits of till and looser drift; 


so that the aim of the prospectors is to begin their wells at 
points where the rock will be reached at as small a depth as 
possible. But so completely have the pre-glacial lines of 
erosion been obliterated in many places in Ohio, that it is 
impossible to caleulate the proximity of the rock to the sur- 
face. Where the deepest drift was penetrated (530 feet in 
Champaign county), special effort was made to locate the 
boring where the superficial deposits were shallow; but, as 
the result proved, the surface indications were deceptive and 
a serious mistake was made, involving the contractor in great 
loss. It should, however, be observed’ that the deep well 
at St. Paris lies in the line of one of the great terminal 


moraines traced by Mr. Leverett across central Ohio, and’ 
where the depth of the glacial deposits is supposed to be’ 


excessive €ven in a moraine. 


Mr. Upham estimates the mantle of drift that conceals 
the rocks in central Minnesota to be between 100 and 200° 


feet deep. In the Red River region, to the north, and over 
a wide belt stretching many hundred miles along the flanks 


of the Rocky Mountains, in the Dominion of Canada, ‘the’ 


eas 


—— so 


© A AD le 


ne a gt llama ly me ae 


GLACIAL EROSION AND TRANSPORTATION. 259 


depth is equally great. In the upper valley of the South 
Saskatchewan, at an elevation of about 4,000 feet above the 
sea, and from 600 to 700 miles west of the Laurentian axis, 
from which much of the glaciated material came, Mr. McCon- 
nell reports sections of till 125 feet deep.* 

Professor Stone thinks the average thickness of the drift 
in Maine is between thirty and fifty feet. Mr. Upham’s 
early calculations for New Hampshire were much more mod- 
erate, namely, ten feet.t But he now informs me that he 
would make a much higher estimate. Besides, in so mount- 
ainous a district, we should expect a thinner deposit to re- 
main on the surface. The more rapid streams would trans- 
port a larger portion of the material to the sea than from the 
gentle slopes. Furthermore, the rocks of New Hampshire 
are better calculated to resist erosion than in some other por- 
tions of the country. Much of the soil of New Hampshire 
has been transported to the States farther south. No re- 
liable estimate has been ‘made of the average depth of 
the glacial accumulations over Massachusetts, Connecticut, 
and Rhode Island. There can be little doubt, however, that 
it is much greater than Mr. Upham makes for New Hamp- 
shire. . 

Professor Shaler { sets down the total amount of drift in 
New England and its neighboring terminal moraines at 750 
cubic miles, or more than the mass of the White Mountains. 
If evenly distributed, this would make a layer of about sixty- 
five feet. 

Professor Lesley says the depth of the glacial drift over 
the northeastern counties of Pennsylvania is not less than 
fifty feet. This is on the summit of the Appalachian plateau, 
while the old valleys, filled with glacial débris, are some of 
them of great depth. One on Mehoopany Creek, in Wyo- 
ming county, is filled with drift to a depth of more than 235 


* “ Report of the Cypress Hills,” 1886. 
+ ““New Hampshire Geological Report,” vol. iii, p. 298 
t “Illustrations of the Earth’s Surface: Glaciers,” p. 58 


260 THE ICH AGE IN NORTH AMERICA. 


feet. In this vicinity, Professor I. C. White * reports wells 
fifty feet deep which barely reach through the till, and this 
on elevations 1,335 feet above tide. | 

Great as thee amounts may seem, the estimation of the 
erosion in the Scandinavian Peninsula by Professor Helland 
is still larger.t Helland, after conference with several 
geologists familiar with the region, estimates that the aver- 
age depth of the drift over north Germany and northwest 
Russia is 150 German feet. This would indicate that the 
erosion from the Scandinavian Peninsula had been as much 
as 250 feet, since the material has nearly all been derived 
from. Scandinavia, and the area of the source of supply in 
Scandinavia is only two fifths of that over which it was dis- 
tributed. 

This estimate of Helland for Scandinavia is not, how- 
ever, greater than that of Professor Lewis for northern 
Pennsylvania. Here, on the Kittatinny Mountain, near the 
Delaware Water-Gap, this observer seems to have had a 
rare opportunity for directly measuring the eroding power 
of the ice at that point.t The summit of the mountain is 
crowned by compact strata of Medina sandstone, and trends 
northeast by southwest. The glacier surmounted the ridge 
on both sides of the Water-Gap, and extended twelve or 
fifteen miles farther south, while to the scuthwest the sum- 
mit of the mountain was outside of the line of ice-movement, 
which just here is bordered by cliffs of the crowning Medina 
sandstone seventy feet high, as if the ice, in moving past 
them, had worn down the strata underneath to that amount. 
Professor Lesley, at the Minneapolis meeting of the Ameri- 
can Association for the Advancement of Science, in 1884, 
took this as a measure of glacial erosion to illustrate how 


* See “Second Geological Survey of Pennsylvania on Wyoming, Lackawanna, 
Luzerne, Columbia, Montour, and Northumberland Counties G’,” p. xiii. | 

+ “Ueber die Glacialen Bildungen der nordeuropaischen Ebene, Deutsch. 
Geol. Gesell.,” Zft. xxxi, 1879, p. 97. 

+ “Second Geological Survey of Pennsylvania Z,” pp. 70, 90. See also 


above. p. 196. 


GLACIAL EROSION AND TRANSPORTATION. 261 


sinall it was. But Professor Newberry well replied that, if 
there was that amount of erosion so near the margin, what 
must it not have been farther back, where the stream of ice 
had acted for an indefinitely longer time. Probably, how- 
ever, Newberry is extravagant when he estimates that farther 
north the ice was ten times as thick, and continued to act 
ten times as long, making its erosive power one hundred 
times as great as that near the Water-Gap.* 

The foregoing evidence of glacial erosion drawn from 
the extent of marginal glacial deposits is complicated by our 
ignorance of the extent to which disintegration of the rocks 
had proceeded before the Glacial period. Professor Whit- 
ney t and Mr. Pumpelly ¢ have specially pressed this point, 
as have Professor Sterry Hunt and the late Mr. L. 8. Bur- 
bank,* to whom more credit is due than he has generally 
received for his early and sagacious suggestions upon the 
subject. The contrast between the glaciated and the un- 


ee 


Fie. 77.—Ideal section showing result of disintegration in an unglaciated region. 
(Chamberlin. ) 


glaciated region, in the extent to which the surface rocks are 
disintegrated by subaérial agencies, is very striking. South 
of the glaciated region granitic masses and strata of gneiss 


* “School of Mines Quarterly,” p. 12. 
+ “ Climatic Changes,” p. 7 ef seq. 
t “ The Relation of Secular Rock-Disintegration to Loess, Glacial Drift, and 
Rock Basins,” in the “ American Journal of Science,” vol. exvii, 1879, p. 133 
et seq. 

* “On the Formation of Bowlders and the Origin of Drift Material,” in 
the “ Proceedings of the Boston Society of Natural History,” vol. xvi, Novem- 
ber 19, 1873. 


262 THE ICH AGE IN NOKTH AMERICA. 


are often completely disintegrated to a great depth, some- 
times amounting to scores of feet. What seem like beds of 
gravel (and which can be handled with a shovel) often prove 
to be horizontal strata of gneiss from which the cementing 
material has been removed by the slow action of percolating 
acids brought down by the rains. North of the glacial 
boundary it is very rare to find any such extensive evidence 
of disintegrating agencies. Since the ice passed over this 
region there has not been sufficient time for subaérial agen- 
cies to produce any marked disintegrating effect. 

Now, it is with much plausibility contended that the 
action of the ice has been limited chiefly to the transporta- 
tion of this disintegrated material, and that it has had little 
effect as an eroding agency. ‘The strong point in this repre- 
sentation is, that there is little more loose soil over the 
margin of the glaciated region than would result from the 
simple transportation of the disintegrated material from the 
northern and central portions of the glaciated region to the 
marginal area. It certainly is clear, both from the necessities 
of the case and from actual observation, that the area of 
greatest erosion is nearest the center from which the ice 
radiated, and that, as the amount of deposition increased 
toward the margin, the erosion diminished. 

The advocates of the great erosive power of glacial ice 
appeal, also, to the general appearance of the glaciated sur- 
faces wherever exposed. The islands near Sandusky, in the 
western part of Lake Erie, for example, present some of the 
most marked indications of glacial erosion anywhere to be 
found, and the facts there are justly appealed to by Professor 
Newberry in support of the theory that the ice was a promi- 
nent agent in the formation of the basins of the Great 
Lakes. 

As this is so important a region for glacial study, I will 
give somewhat in detail the result of my own recent obser- 
vations. There are twelve or fifteen islands near the west- 
ern end of Lake Erie, of which Kelly’s, North Bass, Middle 
Bass, South Bass, and Pelee are the principal, each having 


a a dh een ty. Sit PY hr 


ee ee 


GLACIAL EROSION AND TRANSPORTATION. 263 


an area of several square miles, and none of them rising 100 
feet above the surface of the lake. They all consist of the 
hard limestones of the Niagara series. In every instance, as 
one approaches them from the eastern side, his attention is 
attracted by the remarkable depth and continuity of the 
glacial grooves running nearly east and west upon them, and 
which rise out of the water, and continue to the summit of 
the islands, or until they are covered by the ground moraine 


which has not been washed away by the waves. In some 


Fie. 78.—Glacial grooves on east side of South Bass Island, Lake Erie, running west 10° 
south. 


instances, these grooves are two or three feet deep, and ex- 
tend many rods in plain sight. Nor are they in all cases 
straight, but sometimes are extremely tortuous, winding along 
in their course like the channel of a sluggish stream. It is 
evident, in some cases, that the main features of these deep- 
est grooves have been determined by preglacial or subglacial 
water-action, and that the ice, or the ground moraine under 


=" 
ead 


Fie. 79.—Tortuous grooves on Kelly’s Island. Lake Erie. United States Geological 
Survey (Chamberlin). 


GLACIAL EROSION AND TRANSPORTATION. 265 


the ice, has moved along in a previously formed mold, 
scouring it out and polishing it, and somewhat enlarging it. 
Thus it comes about that sometimes even the under surface 
of a projecting rock has been scratched and polished by the 
ice-movement. In ease of the shallower grooves, two or 
three inches or less in depth, the abrupt variations are numer- 
ous, as if a pebble had encountered an obstacle to its direct 
movement, and turned aside to move onward in a new line 
of least resistance, the general course remaining substantially 
the same. 

That there has been here considerable erosion by direct 
action of the ice there can be no doubt; but that it is less 
than some suppose is perhaps shown from the cross-strie, 
which indicate four distinct but successive movements. The 
course of events was plainly as follows: 

1. When the advancing ice filled the valley of Lake Erie, 
but had not surmounted the summit of the water-shed to the 
south, and before the Illinois lobe of ice had extended across 
Lake Erie’s natural southwestern outlet, the ice-movement 


in Lake Erie was in the line of the longest diameter of the 


lake—i. e., southwest. 

2. During the height of the Glacial period, when the ice 
surmounted the water-shed between the lake and the Missis- 
sippi basin, about one hundred miles to the south and from 
five to seven hundred feet higher, the movement of the 
ice was very nearly north by south. There was then no 
opportunity for the ice to escape from the southwestern end, 
because of the larger general movement of the glacier across 
its pathway. So powerful was this movement in a southerly 
direction that deep north-and-south channels were eroded in 
all the islands. 

3. But, upon the retreat of the ice to the water-shed, and 
the withdrawal of the glacier, which crossed its way on the 
southwest, the former westerly line of movement was at once 
resumed. Each later movement has done much to obliterate 
the marks of the earlier. Upon the eastern slopes this oblit- 
eration is sometimes complete. But wherever there was a 


266 THE ICH AGE IN NORTH AMERICA. 


lee side of a prominence in which a north-and-south glaei- 
ated surface could be protected from the force of the eastern 
current, we find that it was protected, and the glaciated sur- 
face is as fresh on the removal of the soil as it is anywhere. 
In places the beveled edges of earlier grooves are perfectly 
distinct where the second cross-movement has obliterated a 
part of a groove, and left still untouched the portion of the 
earlier groove which was protected by a ridge. Within a 
half mile of each other there are grooves several inches in 
depth running at right angles to each other. For instance, 
upon the west side of Gibraltar (which is a small, rocky island 
at the mouth of Put-in Bay, close to South Bass Island), there 
- are deep grooves, running north by south, made by the sec- 
ond movement; but they were perfectly protected by the 
rock, which received the brunt of the third movement as it 
came from the east. One half mile west, and a little south 
of this point on the main island, where there is a shallow 
valley across the island, the east-and-west grooves are equally 
striking. This was doubtless the movement whose record is 
left in the moraine of the Maumee Valley, as already described 
by Gilbert.* 

4. There were also indications of still a fourth movement, 
which set in when the ice had receded so far that the obstruc- 
tion presented by the elevation of the water-shed to the south 
would no longer compel a westerly movement. But, when 
the ice-front was between these islands and the south shore, 
the movement would again be, according to theory, to the 
south, at right angles to the first and third movements. This 
last movement, however, was probably feeble and not of long 
continuance. Still, there are some signs of it in the shape 
of shallow strize across the second set of east-and-west fur- 
rows. While all this is witness to the efficiency of ice as an 
eroding agency, it conveys the impression that the erosion 
accomplished by each successive movement was concentrated 
in special channels, and was nowhere excessive. 


* See p. 207 


e Ps 
” 
— 


eo --—_ 


GLACIAL EROSION AND TRANSPORTATION. 267 


Fic. oe —Section of east and west glacial furrows, on Kelly’ sIsland. Till rests imme- 
diately on the rock, ‘with washed pebbles at the surface. 


The following very important extracts concerning glacial 
erosion, from the recent report of Mr. I. C. Russell, need 
no introduction and no comment : 


That the rock-basins in the high Sierra were excavated by 
glaciers the writer finds no reason whatever to question. They 
frequently occur at the lower limit of a steep slope, which is 
polished and grooved, and bears every indication of having 
been abraded by glacial action. In such cases the slope and 
the direction of the furrows show that ice once descended into 
the basin. On examining the opposite portion of the rim of 
the depression, glacial markings of the same character will be 
found. The proof is thus positive that the ice descended into 
the depressions now filled with water, and emerged from them ‘ 
again to continue its course. As there is no other agent known 
capable of eroding hollows in solid rock having the character 


*9AO[SUNOX *O “WW Jo Asa1n0p9) 


‘Surpecerd oy1 sv omUg—*[g “Sly 


GLACIAL EROSION AND TRANSPORTATION. 269 


of the basins observed in the high Sierra, it seems evident that 
the theory of the formation of rock-basins proposed by A. C. 
Ramsay, from evidence obtained in Scotland and Switzerland, 
is substantially correct, and furnishes the true explanation of 
the origin of the examples before us.* The manner in which 
the power of moving ice is directed so as to erode depressions 
may be open to discussion, but the conclusion that rock-basins 
are a result of glacial action is now too strongly supported by 
facts to be questioned. .. . 

On examining the numerous lakes more critically, one finds 
that many of them occupy depressions in morainal dédris, or 
are confined by terminal moraines. In numerous instances, 
however, as in Bloody and Gibbs Cafions, at the head of Rush 
Creek, and all about Mount Lyell and Mount Ritter, the fact 
that the lakes occupy depressions in solid rock is beyond ali 
question. One may waik entirely around many of them with- 
out stepping off rock in place... . 

As some writers—especially those who are given to solving 
the mysteries of Nature from their closets—have thought that 
lakes filling true rock-basins are a rarity, and have even doubt- 
ed whether they exist at all, we shall be interested in examin- 
ing this result of glacial action, while we wait for our mule- 
train to join us. The stream from above cascades over hun- 
dreds of feet of rock before reaching the lake ; on either hand 
the overshadowing cliffs tower upward for a thousand feet ; 
and we can walk along the lower border of the lake and find 
solid rock all the way across the cafion. There is no doubt, 
therefore, that the lake occupies a basin in solid rock. The 
ledge confining the waters rises in places almost perpendicu- 
larly to the height of over a hundred feet above the lake sur- 
face, and indicates by its rounded contour and polished and 
striated sides that the ice was once forced up from the basin, 
now filled with water, and flowed over the ledges and down the 
gorge. The sounding-line tells us that the bottom of the 
basin is fifty-one feet below the lake surface. We thus have 
a rock-basin of considerable depth, in the path of a glacier, 


* “On the Glacial Origin of Certain Lakes,” ete., “ Quarterly Journal of the 
Geological Society of London,” vol. xviii, 1862, pp. 185-204. 


270 THE ICE AGE IN NORTH AMERICA. 


the unmistakable markings of which descend into it on the 
upper side and emerge again at its lower margin.* 


rest 10° south, 


, running w 


le of South Bass Island 


, SIC 


Fig. §2.— Glacial furrows on west 


There is so much general interest in the question as to 
the formation of the Yosemite Valley that we append the 
remarks of the same high authority concerning it: 


# « The Quaternary History of Mono Valley, California,” pp. 281, 368, 369. 


A lla 


GLACIAL EROSION AND TRANSPORTATION. 271 


It is the opinion of the writer that the excavation of many 
of the valleys of the Sierra Nevada began long previous to the 
Quaternary, and are in fact relics of a drainage system which 
antedates the existence of the Sierra as a prominent mountain- 
range. 

Those who seek to account for the formation of the Yo- 
semite and other similar valleys on the western slope of the 
Sierra by glacial erosion should be required to point out the 
moraines deposited by the ice-streams that are supposed to 
have done the work. The glaciers of this region were so 
recent that all the coarse dédris resulting from their action yet 
remains in the position in which it was left when the ice 
melted. If the magnificent valleys referred, to are the result 
of glacial erosion, it is evident that moraines of great magni- 
tude should be found about their lower extremities. Observa- 
tion has shown that dédris piles of the magnitude and charac- 
ter required by this hypothesis are notably absent. 

It is perhaps not disgressing too far to state that the 
writer, while visiting the Yosemite, could not avoid adopting 
an hypothesis advanced some years since by J. D. Whitney, to 
the effect that the main characteristics of the valley are due to 
dislocation ; or, in other words, that the orographic block be- 
neath the valley has subsided. No facts were observed, how- 
ever, conflicting with the conclusion of Clarence King that 
the valley was occupied at least in part by glacial ice. The 
majestic domes of the Yosemite region have not been rounded 
by glacial action as some writers have supposed, but have been 
produced by the weathering of granite, in which a concentric 
structure on a grand scale was produced when the rocks were 
in a plastic condition.* 


Another illustration of the anomalous erosive power of 
glacial ice is seen in the so-called cergues so abundant in gla- 
ciated regions containing mountains. Here, again, we are 
under great obligations to Mr. Russell for his careful report 
upon these features of the high Sierra. Little is to be added 
to his discussion of the subject. 


* “The Quaternary History of Mono Valley, California,” pp. 350, 351. 


212 THE ICE AGE IN NORTH AMERICA. 


One of the most striking features in the sculpturing of the 
high Sierra is furnished by the grand amphitheatres or cirques, 
occurring about the more elevated peaks and crests. These are 
deep semicircular excavations, bounded on all sides, except that 
through which the drainage escapes, by bold cliffs or by per- 
pendicular walls from a few hundred to more than a thousand 


Fic. 83.—Glacial furrows on Gibraltar Island, one half mile from preceding, but running 
nearly north and south. 


feet in height. The bottoms of these excavations are often 
depressed below that portion of the rim through which the 
drainage escapes, and form rock-basins; at other times the 
basins are partially inclosed by dédris, and in some instances 
they have well-formed terminal moraines across their outlets. 
In these hollows there are transparent lakes of azure blue, 
which reflect the grandeur of the sheltering walls with wonder- 
ful distinctness from their unruffled surfaces. A horizontal 
cross-section of a cirgue is semicircular or horseshoe-shaped, 
and in certain portions of the range these are so numerous that 
they give a scalloped contour to the faces of the cliffs. The 


ah 
>i 
A 


@LACIAL EROSION AND TRANSPORTATION. 273 


interiors of some of the amphitheatres are terraced in the same 
manner as are the bottoms of the cafions leading from them, a 
feature which has been observed in the cirques of the Rocky 
Mountains as well. Nearly all the various branches of the 
ancient glaciers of the high Sierra headed in deep recesses of 
the character above described. In places the cirques occur on 
either side of a fragment of table-land, and have been eroded 
back until only a knife-edge of rock, so narrow and broken 
that the boldest mountain-climber would hesitate to traverse 
it, is all that divides one profound depression from another. 
Examples of this nature are common about Mounts Lyell 
and Ritter, and find a number of typical illustrations in the 
cliffs of the Kuna and Koip crests. At the head of Rush 
Creek are a number of separate cirques, each holding a gem- 
like lakelet, in which the various branches of the stream drain- 
ing the basin have their source. Silver Creek heads in a 
magnificent amphitheatre formed by the union of several 
cirques, which during the height of the Glacial epoch was 
completely filled with névé. On the south side of Kuna and 
Koip peaks are two vast amphitheatres which rank among the 
finest in the Mono region. . . . No topographic delineation or 
word description can convey the impressive grandeur of some 
of these vast, shrine-like recesses that have been sculptured 


_ during the lapse of centuries from the rugged cliffs of the high 


Sierra. 

In general the cirques open northward, but many excep- 
tions to this rule can be found, especially about the head-waters 
of Rush and Silver Creeks. 

It is in the cirques about the higher peaks that living 
glaciers are still found, and those not harboring perennial ice 
are deeply filled with snow during a large portion of the year. 
The slow melting of the snow and ice in these reservoirs feeds 
the rills which join one with another to form the creeks flow- 
ing into Lake Mono. The balance between the climatic con- 
ditions favorable to the existence of glaciers and those which 
insure their disappearance is here nicely adjusted. and, should 
the equilibrium shift to the side of greater congelation, these 
ancient cirgues would be the first points to exhibit the changed 
conditions. They were the fountains which gave birth to the 


274 THE ICE AGE IN NORTH AMERICA. 


ancient glaciers, and were also the last strongholds to be aban- 
doned when the reign of ice approached an end. 

Such amphitheatres are known in all mountain-regions 
where glaciers have existed. It has been the good fortune of 
the writer to examine them on some of the higher peaks of 
Colorado and New Mexico, about the crests of the Wahsatch 
and East Humboldt Mountains, as well as in Switzerland and 
New Zealand. Their origin is somewhat problematic, and has 
occasioned much discussion, as is well known to all who have 
followed the growth of glacial literature. 

In an article on the formation of cirques, by T. G. Bon- 
ney,” an attempt was made to prove that these peculiar feat- 
ures of mountain sculpture are the result of stream-erosion, and 
owe few if any of their characteristics to ice-action. 

The studies of B. Gastaldi,+ on the effects of glacial ero- 
sion in Alpine valleys, led him to reject Bonney’s hypothesis, 
and to conclude that they are a result of ice-erosion. 

The most extended as well as the most instructive essay 
concerning their formation that has come under the writer’s 
notice is from the pen of Amund Helland, entitled ‘‘On the 
Ice-Fiords of North Greenland, and on the Formation of 
Fiords, Lakes, and Cirques in Norway and Greenland.” { In 
this essay a clear and concise description of the cirques of 
Norway, Switzerland, and other regions is given, together 


with a brief summary of the various hypotheses that have — 


been advanced in explanation of their origin. Strong evi- 
dence is also presented to show that they are a result of glacial 
action. In Helland’s essay are included the views of Lorange, 
of the Norwegian Royal Engineers, who arrived at the con- 
clusion that they are formed principally by the effects of 
great changes of temperature in the vicinity of glaciers. We 
quote Lorange’s observations and conclusions as stated by Hel- 
land : 

‘‘Under the glaciers in cirques, where a space intervened 
between the bed of the cirque and the ice, he saw a great many 


* “Quarterly Journal of the Geological Society,” London, vol. xxviii, 1872, 
pp. 312-324. 

+t Ibid., vol. xxix, 1872, pp. 396-401. © 

{¢ Ibid., vol. xxxiii, 18738, pp. 142-176. 


ee eee 


ne natal ettmee =  o 


ee eee 


= ee en eee ae 


Nite oe 


‘ 


GLACIAL EROSION AND TRANSPORTATION. 275 


stones, some of which, sticking fast in the glacier, were quite 
lifted up from the bed of the cirgue, while others were touch- 
ing or resting on it; he thinks it probable that, as the tem- 
perature around the glacier constantly varies about the freez- 


Fic. $£—Glacial groove on Middle Bass Island, running nearly east and west, with a 
north-and-south groove crossing it. Notice the beveled edge of the east-and-west 
groove, which is here descending to the west. 


ing-point, the incessant freezing and thawing of the water in 
the cracks in the rock may split it, and the glacier may do the 
work of transportation for the fragments thus broken loose. 
On examining the interior of an empty cirque, we observe 
that a bursting, not a scooping out, of the rocks has taken 
place.” 

The writings of Penck, Léwl, and other European geolo- 


276 THE ICE AGE IN NORTH AMERICA. 


gists might be cited here, but it is not my intention to review 
the entire literature of the subject. , 

Sufficient observations have been recorded to show not 
only that cirques are of nearly world-wide distribution, but 
that they are confined to glaciated regions, and are not found 
in mountains where undisputed records of glacial action are 
absent. This in itself is good evidence that they have resulted 
from glacial erosion. The same conclusion is indicated by the 
fact that as a rule they open northward—that is, they occupy 
positions where glaciers first appear when a lowering of tem- 
perature renders their existence possible, and where they lin- 
ger longest when the climate ameliorates. It thus seems un- 
necessary to discuss in the present paper the various hypothe- 
ses which refer their origin to water erosion, crater elevation, 
ete. 

The descriptions presented in the essays we have cited, 
together with the observations of the writer, show that the 
cirques of the high Sierra are typical of their class, and present 
all the features to be seen in other similar regions. It is thus 
rendered evident that, if we can arrive at an acceptable expla- 
nation of their origin, it should explain the like phenomena 
in other regions as well. The writer has no mature theory to 
offer, but hopes to contribute something toward the desired 
end. 


It is usually difficult to draw a definite line between a — 


glacial cirque and the cafion leading from it. One is a contin- 
uation of the other. It is evident, also, that the walls inclos- 
ing a cirque have many features in common with the scarps so 
frequent in glaciated cafions. When the cirques themselves 
are terraced, this analogy is rendered still more complete. ‘The 
writer’s studies in the high Sierra and elsewhere have led to 
the conclusion that such scarps and ci;gzes result mainly but 
not wholly from glacial action. The initiation of the process, 
at least in the high Sierra, as in the case of many glacial 
cafions, must have been by subaérial erosion. 

Lorange’s observations show that when a mévé fills a 
cirque it is capable of removing blocks of rock from the inclos- 
ing walls. The fact that these walls are rough and angular, 
instead of smoothly polished, is proof that there is but little 


es ro 


ee ee 


a 


GLACIAL EROSION AND TRANSPORTATION. 277 


abrasion during the settling and consolidation of the névé in 
the amphitheatres in which it accumulates. At the bottom of 
the depressions, however, the conditions are different. Intense 
glaciation there takes place, as is attested by the rounded 
and striated surfaces, and by the occurrence of rock-basins. 
The ice filling a cirque impinges with great weight upon its 
bottom and in its motion outward tends to deepen the exca- 
vation. At the same time the blocks loosened from the walls 
of the cirque are carried away by the outward flow of the ice. 
There are thus at least two processes which unite in enlarging 
and deepening these peculiar features of glaciated mountain- 
tops. 

When a glacier leaves a cirgue and flows down a cajion 
the grade of which is uneven, the erosion of the ice-stream will 
also be uneven. The reason is that the ice in descending a 
steep slope exerts its greatest force at the base of the incline in 
the same manner as in the excavation of cirgues. The tend- 
ency of a moving ice-stream in descending a steep slope is to 
increase the inequalities of its bed ; this tendency, it seems 
probable, will lead to the formation of both scarps and cirques 
when the drainage of a high-grade valley is changed from.a 
liquid to a solid form. To illustrate: The grade of mountain. 
streams increases toward their sources, and when their gorges 
_become occupied by ice, the irregularities of their channels 
—caused principally by the meandering of streams, thus leay- 
ing projecting bosses on either side—may cause ice-cascades 
in the glaciers. An ice-cascade exerts the greatest erosive 
power at the base of the scarp which it descends, thus aug- 
menting the inequality. At the same time the cafion is broad- 
ened and the minor features resulting from stream-erosion are 
erased. The steeper the grade the more pronounced would be 
the action of the ice in remodeling and strengthening the ma- 
jor inequalities of its bed. The resulting scarps and terraces 
should therefore be most numerous and best defined near the 
heads of the channels in which they occur.* 


The prevalence of czrques is also graphically described 
by Dr. G. M. Dawson in his “ Report upon the Forty-ninth 


* “The Quaternary History of Mono Valley, California,” pp. 352-355. 


278 THE ICE AGE IN NORTH AMERICA. 


Parallel.” Speaking of the streams which rise in the Rocky 
Mountains, he says : 


The upper ends of the valleys surrounding the higher peaks 
and ridges are generally very abrupt and take the form of 
cirques, or amphitheatrical depressions of great depth, in the 
mountain -sides. The backs and sides of these are often 
nearly vertical, and they are sometimes only separated later- 
ally, by steep, knife-edge-like ridges, the crests of which form 
the most practicable paths to the summits. Hach of these 
‘upper terminations of the valleys generally also shows a small 
lake or pond in the hollow of the surrounding cliffs, the basin 
of which has evidently been formed by glacier-ice—which must 
here have been descending almost vertically—in the moraine 
matter or shattered rocky floor. . . . The water of the smaller 
lakes in the upper ends of the valleys, as seen from the heights 
around, is of a beautiful semi-opalescent indigo-blue, and must 
be of considerable depth.* 


These facts confirm the theories of the leading glacialists 
of Europe—for instance, Dr. Albrecht Penck, who ascribes 
the excavations of the most important lake-basins in Bavaria, 
like the Ammer See and Wurm See, to glaciers, and states 
that ‘a lake-basin filled with water or sediment lies at the 
mouth of each of the Alpine valleys through which glaciers 
protruded in ancient times.” ¢ 

- The Scotch lochs, and the rock-basins of Norway, would 
seem to be due to the same cause. It is probable also that 
the fiords of Norway and of British Columbia owe their 
greater depth near their heads to the same anomalous influ- 
ence of ice-erosion. Most of the arguments urged against 
the theory are based upon @ priori reasons urging the impos- 
sibility of any such result from such a cause. Of this more 
will be said when speaking a little later of the irregular depo- 
sition of glacial débris underneath the moving ice. 

Not enough is known about the nature of ice to affirm 


* Pace 245. 
+ Quoted by Newberry, in “School of Mines Quarterly,” January, 1885, p. 10. 


—. 


ee ee oe 


owe ohh te e® 


GLACIAL EROSION AND TRANSPORTATION. 279 


that it does not conform to the law of other moving fluids, 
Probably there is no reason why an ice-cascade should not 
produce results of erosion analogous to those of a waterfall. 


Summarily stated, our conclusions are that, like every- 
thing else connected with the action of such a complicated 
cause as that brought into view in the production of glacial 
phenomena, the exact extent of its erosive and transporting 
power is difficult to determine. The action of ice over the 
glaciated region took place after other forces had been in full 
operation during long ages; and hence it is often impossible to 
separate the effects of the second cause from those of the first. 

But there can be no doubt that running water is by far 
the most efficient of all eroding agencies which have given 
shape to the contour of the continents. Most important re- 
sults follow from the power of water to act as a solvent. 
Extensive regions have been undermined and _ lowered 
through the removal by water of the soluble salts. Such has 
perhaps been the origin of many of the valleys of the Appa- 
lachian region and of some cf the great lakes of the world. 
Running water is also a most effective mechanical agency, 
continually acting along the natural lines of drainage. The 
sand and gravel rolled along over the bottom of a rapid 
stream of water act like a rasp or a saw, and have everywhere 
worn deep narrow channels across the slowly rising mountain- 
chains. Water as an eroding agency has had a great advan- 
tage over ice in the far greater length of time during which 
it has been in the field to operate. 

Still, it can not be doubted that ice has had no small part 
in transforming the appearance of the portions of the world 
to which it has had access. Of this the evidence is abundant. 
in the great number and size of the bowlders scattered over 
the glaciated region, hundreds of miles from their native 
ledges, and weighing hundreds and even thousands of tons. 

Inasmuch as ice is frozen water, its melting furnishes the 
torrents to aid in the transportation. The finely comminuted 
material ground up underneath the ice is largely carried away 


280 THE ICE AGE IN NORTH AMERICA. 


_ 


by the torrential subglacial streams continually pouring out 
from the ice-front. It is doubtful if the larger part of the 
glacial grist is not thus transported far beyond the limit of 
the glaciated region. 

Notwithstanding the great waste, the extent of the glacial 
deposits yet remaining over the southern portion of the gla- 
ciated region is immense. Probably not less than 1,000,000 
square miles of territory in North America is covered with 
an average depth of fifty feet of glacial débris, forming the 
most permanently productive portion of the continent. It 
is in the extent of these glacial deposits, and in the certainly 
great amount of transportation by subglacial streams, that we 
have our most certain and impressive evidence of the enor- 
mous activity of erosive agencies during the Glacial age. 


eae apte. aint ae 


a a re rr si 


Fre. 85—Towan bowlders south of New Hampton, Iowa. (Photo by Calvin.) 


CHAPTER XI. 


DRUMLINS. 


eS 


“Drumiix” is the name now used to designate the ciass 
of glacial accumulations which Professor Hitchcock origi- 
nally called “ lenticular hills.” These abound in the vicinity 
of Boston, and large- 
ly give character to 
the scenery of the 
three northeastern 
counties of Massachu- 
setts. They are not, 
however, evenly dis- . 
tributed over the re- 7 ore : 
gion. Familiar ex- BROOKLINE & ee 
amples of them are | A 
Beacon Hill, Boston ; 
Bunker Hill, in 
Charlestown; Breed’s 
Island Hill, beyond 
East Boston; Green 
Hill, in Winthrop; 
Pewder-Horn Hill, 
in Chelsea ; Mount 
Revere ; Mount 
Washington, in Ever- 
ett; Tuft’s College Hill; Winter Hill and others, in Somer- 
ville; Bigelow Hill, in Brighton; White’s Hill, in Water- 
town; Owl Hill, in Waltham; Mount Ida, Prospect, Insti- 
tute, and Oak Hills, in Newton ; Corey’s and Walnut Hills, 


Aeuryg 


Fie. 86.—Drumlins in the vicinity of Boston. (Davis.) 


282 


THE ICE 


AGE IN NORTH AMERICA. 


A typical drumlin. (Davis.) 


Fie. 87.—Corey’s Hill, Brookline, Massachusetts. 


in Brookline ; Parker’s Hill, in 
Roxbury ; Bellevue and the 
Clarendon Hills, in West Rox- 
bury ; Brush Hili, in Milton; 
Jones’s Hill, Mount Ida, and 
Pope’s Hill, in Dorchester ; 
Wollaston Heights, Forbes, 
President’s and Great Hills, in 
Quincy ; Great and King Oak 
Hills, in Weymouth; Baker's, 
Otis, Prospect, and Turkey 
Hills, in Hingham ; Scituate 
and Bear Hills, in Cohasset ; 
Strawberry and Telegraph Hills, 
in Hull; and the hills of Deer 
Island in the harbor. More 
than a hundred others of the 
same character occur within this 
area. 

Mr. Warren Upham’s de- 
scription of these interesting 
features of the landscape is 
most complete and satisfactory : 


These hills vary in size from 
a few hundred feet to a mile in 
length, with usually half to two 
thirds as great width. Their 
height, corresponding to their 
area, varies from twenty-five to 
two hundred feet. But, what- 
ever may be their size and height, 
they are singularly alike in out- 
line and form, usually having 


steep sides, with gently sloping, 


rounded tops, and presenting a 
very smooth and regular contour. 
From this resemblance in shape 


DRUMLINS. 


to an elliptical convex lens, Professor 
Hitchcock has called them lenticular 
hills, to distinguish these deposits of 
till from the broadly flattened or undu- 
lating sheets which are common through- 
out New England. 

The trend, or direction of the longer 
axis, of these lenticular hills is nearly 
the same for all of them comprised 
within any limited area, and is approx- 
imately like the course of the striz or 
glacial furrows marked upon the neigh- 
boring ledges. In eastern Massachu- 
setis and New Hampshire, within twen- 
ty-five miles of the coast, it is quite 
uniformly to the southeast, or east- 
southeast. Farther inland, in both of 
these States, it is generally from north 
to south, or a few degrees east of south ; 
while in the valley of the Connecticut 
River it is frequently a little to the 
west of south. ‘In New Hampshire, 
besides its accumulation in these hills, 
the till is frequently amassed in slopes 
of similar lenticular form. These have 
their position almost invariably upon 
either the south or north side of the 
ledgy hills against which they rest, 
showing a considerable deflection toward 
the southeast and northwest in the east 
part of the State. It can not be doubted 
that the trend of the lenticular hills, 
and the direction taken by these slopes, 
have been determined by the glacial 
current, which produced the strive with 
which they are parallel.* 


* “Proceedings of the Boston Society of Nat- 
ural History,” vol. xx, pp. 224, 225. 


283 


(Davis.) 


Fic. 88.—Outline of drumlins in Boston Harbor. 


284 THE ICE AGE IN NORTH AMERICA. 


To this may be added the following interesting remarks 
by Professor William M. Davis: 


The general uniformity of outline in any single region is 
very noticeable ; indeed, the view from the summit of a com- 
manding drumlin, in the center of a group, shows as character- 
istic a landscape as that seen in looking from the Puy-de-Déme 
over the extinct volcanoes of Auvergne. Moreover, the con- 
trol that drumlins exercise over the laying out of roads and 
the division of property is so complete in districts where they 
abound, that it is the rule to find roads, fields, gardens, and 
even houses oriented in obedience to the march of the old ice- 
invasion. About Bos- 
ton there are hundreds 
of dwellings whose 
walls thus stand in 
close parallelism with 
the glacial scratches 
on bed-rock beneath 
them. * 


Besides the groups 
of drumlins so prom- 
inent in the vicinity 
of Boston, there are 
two or three others 
deserving of mention, 
and which may per- 
haps be brought in. 
to connection with 
them.t One of these, 

Fig. 89.—Drumlins in northeastern Massachusetts. about eight miles wide 
(Davis.) 

and twenty long. and 

containing thirty or forty well-marked individual hills of the 

character described, follows the coast from Beverly to New- 

buryport. Parallel to this there is a belt of country, about 


* *€ American Journal of Science,” vol. exxviii, 1884, p. 409. 
+ See map, p. 338. 


DRUMLINS. 985 


four miles wide, over which scarcely any of these hills are 
found. Still farther inland, a longer range can easily be 
traced. Beginning in the vicinity of Portsmouth, N. H., this 
interior series is well developed, in a southwest direction, 
through Rockingham county to Amesbury, Mass. Thence, 
on, it completely covers the townships in Essex county on 
either side of the Merrimack River to Lowell, and continues, 
with little interruption, through Middlesex county to the 
vicinity of Fitchburg, Worcester county. Toa limited ex- 
tent these same typical hills abound still farther west through 
the northern part of Worcester and Franklin counties to the 
Connecticut River. Areas of them are also reported running 
up from Ashburnham, Mass., to Weare, N. H.; also in the 
western part of Cheshire county, N. H., and in the vicinity 
of Worcester, Mass., as well as about Ambherst and in the 
northeastern part of the State of Connecticut. * 

The following additional facts have been collected by 
Professor Davis : + 


A fine series of drumlins stretches from about Spencer, 
Mass., to Pomfret, Conn., but the detailed study that it would 
well repay has not 
yet been attempted. 
Members of this 
series occur near 
Charlton _ station, 
Boston and Albany 
Railroad, with their 
bases at an elevation 
of nine hundred feet 
above sea-level, and 
others stand still Fie. 90—Onutline of Sen in central New 
higher. The por- 
tion of the group in Connecticut is described by Percival as fol- 
lows: “The district extending north from Hampton, through 


* Upham, in “ Proceedings of the Boston Society of Natural History,” vol. 
Xx, pp. 231, 232. 
+ “ American Journal of Science,” vol. exxviii, pp. 410, 411. 


286 THE ICE AGE IN NORTH AMERICA. 


Abington, Pomfret, and Woodstock, is characterized by a series 
of very smoothly rounded, detached hills, in which the rock is 
usually entirely concealed. ‘These form a.striking contrast with 
the longer and more continuous [rocky] ridges of the adjoining 
formation.” * Professor G. H. Stone reports that drumlins of 
large size, like those about Boston, have not been found in 
Maine. Western New York, between Syracuse and Rochester, 
presents a surprising number of parallel north-and-south drift- 
hills, probably familiar to many travelers by rail. Some of them 
are so long, smooth, and even, that the country thereabout 
has been described as fluted. 'These were long ago described 
by Professor James Hall, in his ‘‘ Geology of the Fourth Dis- 
trict of New York ” (1843) ; since then they have been strangely 


neglected until examined by Dr. L. Johnson, who has lately. 


published a paper, ¢ entitled ‘‘The Parallel Drift Hills of 
Western New York.” Some of the ridges are ‘‘ two or three 
miles long, and attain elevations of one or two hundred feet 
above the intervening valleys; but the greater number are 
shorter and steeper. Many of them were, when first cleared 
of timber, very steep at their north ends, and on their east 
and west sides; but, with very rare exceptions, the southern 
slope is gradual.” ‘These and other irregularities of form 


Fie. 91.—Drumlins in Wisconsin. (Chamberlin.) 


may require that some of the hills of this region should be 
separated from drumlins as here defined. In Wisconsin, the 


drift-hills, as described by President T. C. Chamberlin, ‘‘are 


arranged in lines, and their longer axes invariably lie parallel 
to the movement of the ice. In some localities, especially 


* “Geology of Connecticut,” 1842, pp. 256, 461, 479, 485. 
+ “Transactions of the New York Academy of Sciences,” vol. i, 1882, p. 77. 


ES Ol 


a 


DRUMLINS. 287 


in Dodge and Jefferson counties, these are mainly replaced by 


- long parallel ridges, sometimes several miles in length, with 


corresponding linear marshes interspersed. These correspond 
accurately to the direction of the ice-motion.”* According to 
Mr. Upham, drumlins are not found in the abundant drift of 
Minnesota. A few examples are mentioned for Pennsylvania, 
near its western border, by Professor Lewis. t 


In endeavoring to account for this class of hills, two or 
three facts are of special importance: 1. The material of 
which they are composed is very heavy and compact—almost 
as heavy and compact, indeed, as ice. Such masses could 
not have been shoved along bodily beneath the ice. In fact, 


Fie. 92.—Drumlins in Goffstown. N. H. (Hitchcock.) 


there would seem to be no reason why they might not resist 
the erosion of the glacier almost as well as many of the softer 
rocks did, especially when we remember that the pressure of 
the ice on the bottom need not have been uniform, but 
greater in some places than in others. 2. There are many 
indications that these hills were formed by accretion under 
the ice, there being, as Mr. Upham has shown, a tendency to 
lamination or coarse glacial stratification in the structure of 


* “Geology of Wisconsin,” vo]. i, 1883, p 283. 
+ “Second Geological Survey of Pennsylvania, Z,” pp. 29, 188. 


288 THE ICE AGE IN NORTH AMERICA. 


the hills.** 38. They are not characterized by kettle-holes. 
The surfaces are remarkably symmetrical, as if having been 
smoothed over by design, and all the irregular depressions 
are filled with homogeneous earth. 4. Up to one hundred 
feet above their base, the flanks of these hills in Massachusetts 
and New Hampshire are frequently covered with the water- 
worn deposits hereafter to be described and known as kames, 
and which are the very last work done by the ice at the 
points where they are found. The drumlins are, therefore, 
earlier than the kames. : 

In structure these hills resemble the lower portions of till, 
or the ground moraine. They are only imperfectly stratified, 
and very compact, and filled with foreign and finely striated 
stones. They are, without doubt, a true glacial deposit ; but 
how comes the deposit to be heaped up in these localities in 
such vast and shapely masses? Professor Shaler surmised 
that they were but the remnants of a continuous ground 
moraine which had been eroded from the whole country, 
except where it was protected by pedestals or underlying 
rock which served to break the force of the beating waves of 
the ocean.t To this ingenious theory there are two fatal 
objections: 1. Drumlins are frequently found where there 
are no rocky pedestals to protect their bases. 2. They occur 
in the interior far above any height to which it is supposed 
the ocean has reached since the Glacial period. ‘The alti- 
tudes at which they occur vary from the level of the sea to 
fifteen hundred feet above it on the height of land between 
the Merrimack and Connecticut Rivers.” + Mr. Clarence 
King would explain them as marking places in the great 
continental glacier where streams of water which had run 
for some distance in superficial channels along the surface of 
the glacier and collected a great amount of débris from the 
medial moraines, had finally plunged through a mowlin into 


* “ Proceedings of the Boston Society of Natural History,” vol. xx, p. 228. 
+ Ibid., vol. xiii, pp. 196-233. 
t Ibid., vol. xx, p. 238. 


ls 


DRUMLINS. 289 


a deeply hidden subglacial river.* Here, it is thought, vast 
cavities might be formed in which these accumulations would 
take place, while, by the movement of the ice, the crevasse 
might be transferred farther down, and so the accumulated 
deposit be subjected to the pressure and sculpturing power 
of the ice. 

Mr. Upham speaks on the subject as follows: “ The finely 
pulverized detritus and glaciated stones in the bottom of the 
ice-sheet had a tendency to lodge on the surface of any de- 
posit of the same material. When such banks of the lower 
till became prominent obstacles to the ice-current, its level- 
ing force was less powerful than this tendency of adhesion, 
which continually gathered new material, building up these 
massive rounded hills.” + Mr. Upham remarks upon the par- 
tial parallelism of these ranges of hills with the extreme ter- 
minal moraine, and, with his usual perspicacity, notes that 
both the glacial strize and the trend of the axes of the len- 
ticular hills nearest the coast in Essex and Suffolk counties, 
bear much more easterly than they do even a few miles in 
the interior. This points with much force to the effect which 
would be produced upon the movement of the ice near its 
margin when it had receded a considerable distance from the 
south, but especially from the east, where the waters of the 
Atlantic had access to the glacier along the margin of what 
is called the Gulf of Maine. When the waters of this gulf 
had eaten the ice well away into the Massachusetts shore, and 
thus removed the barrier to the east, the line of least resist- 
ance would be in that direction, and the current would natu- 
rally swing out toward the open sea. 

While recognizing the force of all Mr. Upham says, I can 
not forbear repeating an additional suggestion of my own 


*I do not know as Mr. King has anywhere published these views, nor, in- 
deed, as he would now be willing to own them, as here stated. They were 
given me in personal conversation, and contain so much that is worthy of con- 
sideration, that I venture to repeat the theory. 


+ “Proceedings of the Boston Society of Natural History,” vol. xx, p. 
234. 


290 THE ICE AGE IN NORTH AMERICA. 


made at the same time,* namely, that these hills perhaps 
represent an earlier moraine than that on the south shore of 
New England—1. e., one which was formed when, on the first 
advance of the ice, it had reached the latitude of Boston, and 
where for some reason it paused until great accumulations 
had taken place along its front; that afterward, upon a fresh 
advance, these accumulations were overrun by the ice with- 
out being leveled; being merely sculptured by it, and read- 
justed to the changing line of general movement; and that, 
finally, the retreat of the ice was so rapid over this region 
that there were no marked terminal accumulations; but the 
superglacial débris settled gently over the whole country, 
constituting the more highly colored superficial blanket of 
débris called by Hitchcock “upper till,” and furnishing the 
larger and more angular bowlders characteristic of the super- 
ficial deposits. I find also that Professor Charles Hitchcock 
had made the same suggestion as early as 1876.t+ 

The long discussion concerning the origin of these singu- 
lar hills would seem to have been brought to a close by the 
careful summary and discussion of facts given by Professor 
Davis, from which we have already quoted : 


The first clear reference to drumlins, as directly dependent 
on glacial action for their form, was made by M. H. Close.f 
They are here said to be parallel to the neighboring striz, and 
hence, like these, dependent on the ice-sheet for their present 
attitude and form. The same conclusion is presented in a 
paper of 1866, when the name drumlin was first specially pro- 
posed for them. Still later, when describing the physical 
geography of the neighborhood of Dublin, Close writes, ‘It 
is perfectly certain that it must have been the rock-scoring 
agent which produced the bowlder-clay ridges.” Besides this, 
Kinnahan and Close, in a pamphlet of 1872, stated their opin- 


* “Proceedings of the Boston Society of Natural History,” vol. xx, p. 218; 
also, “‘ Prehistoric Andover,” p. 4. 

+ Ibid., vol. xix, p.66. Professor N.S. Shaler now favors this view; see the 
“Seventh Annual Report of the United States Geological Survey,” 1888, p. 221. 

+ “Journal of the Royal Geological Society of Ireland,” vol. i, 1864, p. 3. 


DRUMLINS. 291 


ion that drumlins were formed in a way ‘‘ similar to that by 
which a stream of water often makes longitudinal niger of 
sand in its bed.”* This is to 
my mind the best suggestion yet 
given to account for them. 

J. Geikie wrote as follows: 
‘The remarkable linear direc- 
tion of certain mounds of bowl- 
der-clay in some districts of the 
Lowlands, agreeing as this does 
with the general bearing of gla- 
cial markings of the same lo- 
calities, induces us to believe 
that we have here, with certain 
modifications, the original con- 
tour of the till after the super- 
incumbent ice-sheet had disap- 
peared ” ; + but he believed that 
these forms may be also in part 
dependent on marine erosion. 
In the ‘‘Great Ice Age,” the 
same author briefly mentioned 
“the series of long, smoothly 
rounded banks or drums, and 
sow-backs, which run _ paraliel AE Se . 
to the direction taken by the ces Sidibiae 
ice,” and regarded them as very Fie. 93.—Drumlins in Ireland, after Kin- 
ibid ahodatisditvoni thets sce Hien Ainacyeai eS 
form. They are ‘‘ produced by the varying direction and un- 
equal pressure of the ice-sheet,” and are ‘‘the glacial counter- 
parts of those broad banks of silt and sand that form here and 
there upon the beds of rivers.” Dr. I. Johnson says that he 
accepts Geikie’s explanation, and applies it to the New York 
ridges which were “‘ formed underneath the glaciers by alterna- 
tions of lateral pressure” ; but this form of statement does not 
commend itself so highly as the preceding. 


* “General Glaciation of Iar-Connaught,” Dublin, 1872. 
t “Transactions of the Geological Society of Glasgow,” vol. iii, 1867, p. 61. 


292 THE ICH AGE IN NORTH AMERICA. 


In this country, Professor C. H. Hitchcock and Mr. War- 
ren Upham, while engaged on the geological survey of New 
Hampshire, were the first to discover the parallelism between 
glacial motion and the axes of drumlins in 1875. They con- 
cluded that ‘‘ the accumulation of these hills and slopes seems 
to have been by slow and long-continued addition of material 
to their surface, the mass remaining nearly stationary from the 
beginning of its deposition. Obviously this was the case with 
the lenticular slopes gathered behind the shelter of higher 
ledgy hills or upon their opposite sides.” * <A little later Up- 
ham wrote, ‘‘ Although we do not discover the cause of the 
peculiar distribution of these hills, it seems quite certain that 
they were accumulated and molded in their lenticular form 
beneath the ice.” + President Chamberlin’s observations led 
him to a similar conclusion : ‘‘ The drift presents some pecul- 
iar tendencies to aggregation. . . . A special tendency is ob- 
served over certain considerable areas lying not far from the 
Kettle Moraine to accumulate in mammillary or elliptical or 
elongated hills of smooth-flowing outline.” { And again, after 
repeating this opinion, it is suggested that ‘‘a deeply hidden 
boss of rock is usually and perhaps universally the determin- 
ing cause of these peculiar accumulations.” * 

In reviewing these explanations and the observations on 
which they are based, together with such evidence as my own 
studies have discovered, the conclusion that drumlins should 
be compared to sand-banks in rivers appears the most satisfac- 
tory yet advanced. They seem to be masses of unstratified 
drift slowly and locally accumulated under the irregularly 
moving ice-sheet where more material was brought than could 
be carried away. The evidence for the subglacial growth of 
drumlins may be summarized as follows : The scratched stones 
in the mass of bowlder-clay show a differential motion of its 
several parts as they were scraped and rubbed along from a 
generally northern source and gradually accumulated where 


* “Geology of New Hampshire,” vol. iii, p. 308. 

+ “Proceedings of the Boston Society of Natural History,” vol. xx, p. 228. 

t “Geology of Wisconsin,” vol. i, 1883, p. 288. 

* “Third Annual Report of the United States Geological Survey,” 1883. p. 
306. 


DRUMLINS. 293 


now found. The compactness of the mass suggests an origin 
under heavy pressure ; the attitude of the hills demonstrates 
a close dependence on the motion of the ice-sheet ; the super- 
position of kames on their flanks proves that their present 
form was essentially completed when they were uncovered by 
the ice-sheet, and the small change of form in the kames shows 
that the drumlins also can have suffered very little from post- 
glacial erosion ; the faint channeling of their smooth slopes by 
rain measures the small amount of denudation that they have 
suffered since they were made. It must therefore be concluded 
that they were finished closely as we now see them when the 
ice melted away, and hence they were of subglacial construc- 
tion. 

The supposed manner of accumulation of drumlins may be 
briefly sketched. It is well known that a stream of running 
water will at one point carry along silt and sand that must be 
dropped a little farther on where the current slackens, and the 
bank thus begun grows slowly in a form of least resistance, at- 
taining a maximum size when its increase of volume has so far 
diminished the cross-section of the stream and consequently 
increased the velocity that no more detritus can be dropped 
there ; but even then one end may be worn away while the 
other grows, the adjustment of velocity to channel is not per- 
manent. The motion of a glacial sheet has been justly com- 
pared to that of a broad river. The comparison may be ex- 
tended so as to liken the active head-waters of a stream to the 
presumably fast-moving part of the ice-sheet near its source or 
center of dispersion where the greatest erosion generally takes 
place. The delta of a river corresponds to the thinner and 
slower- moving marginal area of an ice-sheet, where drift 
brought from elsewhere is quietly and evenly deposited, as in 
Minnesota, and where erosion is relatively weak. A still fur- 
ther agreement is discovered in comparing the drumlins and 
sand-banks found in the middle course of the molten and solid 
streams as suggested by the several authors quoted above. In 
view of the irregularity of the surface on which the ice-sheet 
moved and of the greater weakness of some rocks than others, 
we must suppose an irregular velocity in the motion of the ice 
and an unequal distribution of the rubbish beneath it. If the 


294 THE ICE AGE IN NORTH AMERICA. 


faster motion at one place cause an excess of erosion there, the 
slower motion at another place may bring about an excess of 
deposition. ‘This difference of action is known to prevail be- 
tween the central and marginal parts of glaciated areas, and 
the local accumulation of drumlins in an intermediate region 
gives a smaller example of these two parts played by the ice. 
If the causes of the irregular motion of the ice lie in the gen- 
eral form of the country, the location of faster and slower cur- 
rents will be relatively permanent ; the districts of faster cur- 
rents would be found where the greatest volume of ice is 
allowed to pass, and some of the points of retardation may be 
the seats of long-continued drumlin-growth. The drumlins 
thus begun will depend less upon the immediately local form 
of the ground than on the topography of a more considerable 
district, and hence we need not suppose every drumlin to have 
begun its growth upon a knob of rock, although the beginning 
of many hills may have been thus determined. Once begun, 
the drumlins will go on increasing in size as long as deposition 
exceeds erosion, always maintaining an arched form of least 
resistance until a maximum size is reached or until the ice 
melts away ; and in their growth they will approach the form 
to which rough, rocky hills would be reduced by the reverse 
process of erosion if time enough were allowed. Under un- 
ending glaciation the whole surface must be rubbed down 
smooth.* 


As these theories relating to the formation of drumlins 
involve the general principles upon which we are to explain 
other evidences of the varying degrees of erosion effected by 
moving ice, we may as well introduce here, as anywhere, Mr. 
Geikie’s general reply to the objections urged from the sup- 
posed nature of the case: t 


Our ice-sheet flowed, we can not doubt, with a differential 
motion : it must have moved faster in some places than in 
others. In steep valleys and over a hilly country its course 


—_ 


* “ American Journal of Science,” vol. cxxvili, pp. 413-416. 
+ “The Preservation of Deposits of Incoherent Materials under Till or 
Bowlder Clay,” in the “ Geological Magazine,” February, 1878, pp. 2, 3, 6, 7. 


—————— er 


DRUMLINS. 295 


would often be comparatively rapid, but very irregular— 
lagging here, flowing quickly there—while in wide, open 
valleys that sloped gently to the sea, such, for example, as 
those of the Forth and the Tweed, the whole body of the ice 
would flow with a slower and more equable motion. As the 
ice-sheet approached its termination, more especially if that 
terminus chanced to be upon a broad and comparatively flat 
region, like East Anglia, the erosive power of the ice would 
become weaker and weaker, for two reasons: first, because of 
its gradual attenuation; and, secondly, because of its con- 
stantly diminishing motion. These, in a few words, are the 
varying effects which one might a priori infer would be most 
likely to accompany the action of a great ice-sheet. And an 
examination of the glacial phenomena of this and other coun- 
tries shows that the actual results are just as we might have 
anticipated, had it been previously revealed to us that a large 
part of our hemisphere was, at a comparatively recent date, 
almost entirely smothered in ice. In places where, from the 
nature of the ground, we should look for traces of great glacial 
erosion, we find rock-basins ; in broken, hilly tracts, where the 
ice-flow must have been comparatively rapid but irregular, and 
the glaciation severe, we meet with roches moutonnées in abun- 
dance, but with very little till ; in the open Lowlands and in the 
broad valleys where the ice-sheet would advance with dimin- 
ished but more equable motion, we come upon wide-spread and 
often deep glacial deposits, and now and again with interglacial 
beds ; while over regions where the gradually decreasing ice- 
sheet crawled slowly to its termination, we discover consider- 
able accumulations of till, often resting upon apparently un- 
disturbed beds of gravel, sand, and clay. 

The distribution of interglacial deposits, therefore, is really 
in itself a proof that they have been overridden by ice. When 
they occur in highly glaciated regions, it is only as mere 
patches, which, occupying sheltered places, have been _pre- 
served from utter destruction. In the opener, low grounds 
they are found in greater force, although in such places they 
almost invariably afford more or less strong evidence of having 
been subjected to much erosion and crumpling. But the. far- 
ther we recede from the principal centers of glaciation, and the 


296 THE ICE AGE IN NORTH AMERICA. 


nearer we approach the extreme limits reached by the ice- 
sheets, the more extensive and the less disturbed do inter- 
glacial deposits become. In a word, they occur in best preser- 
vation where the erosive power of the ice was weakest; they 
are entirely wanting where we have every reason to believes that 
the grinding force was strongest. 

It is needless to refer one to elie petty glaciers of the ae 
and Norway to prove that glacier-ice can not both erode its 
bed and accumulate débris upon that bed at one and the same 
time. A mountain-valley glacier is one thing—a glacier ex- 
tending far into the low grounds beyond the mountains, and, 
it may be, coalescing with similar extensive ice-flows, is 
another and very different thing. No considerable deposit 
could possibly gather below Alpine glaciers like those of Switz- 
erland and Norway ; but underneath glaciers of the kind that 
invaded the low, grounds of Piedmont and Lombardy we know 
that thick deposits of tough bowlder-clay, crammed with 
scratched stones, did accumulate ; and not only so, but that 
these glaciers flowed over incoherent deposits of sand and clay 
containing marine shells of late Tertiary age, without entirely 
obliterating them. ‘The deposits referred to occur now as little 
patches within the area bounded by the great terminal mo- 
raines. 

As physicists themselves are not yet quite agreed upon the 
subject of glacier motion, it is not incumbent upon the geolo- 
gist to explain the precise mode in which a thick mass of ice 
can creep over the surface of incoherent beds without entirely 
demolishing them. It is enough for him to show how the 
remarkable distribution of the interglacial beds, and the vari- 
ous phenomena presented by these deposits, indicate that ice 
has overflowed them. It is useless, therefore, to tell him that 
the thing is impossible. The statement has been made more 
than once that an ice-sheet several thousand feet thick is a 
physical impossibility ; but, unfortunately for this dictum, the 
geological facts have demonstrated that such massive ice- 
sheets have really existed, and there appears to be one even 
now covering up the Antarctic Continent. We used also to be 
told, not so many years ago, that the abysses of ocean must be 
void of life for various reasons, among which one was that the 


DRUMLINS. aor 


pressure of the water would be too great for any living thing 
to endure. Yet many delicate organisms have been dredged 
up from depths at which the pressure must certainly be no 
trifle. Now, there seems to be just as little difficulty in beliey- 
ing that these organisms existed in a perfect state at the bot- 
tom of the ocean, as that shells imbedded in clay would remain 
unbroken underneath the pressure of a superincumbent ice- 
sheet of equal or greater weight. If the ice were in motion, 
the clay with its included shells might be plowed out bodily, 
or be merely crumpled and contorted ; or it might be ridden 
over with little or no disturbance ; or, on the other hand, it 
might become involved with subglacial dédris, and be kneaded 
up and rolled forward—the shells in this case being broken, 
crushed, and. striated, just as we find that the shells in certain 
areas of till have been. The fate of the fossiliferous beds 
would, in short, be determined by the rate of flow and degree 
of pressure exerted by the superincumbent quwasi-viscous body 
—the motion of which would be largely controlled by the 
physical features of the ground across which it crept. 


CHAPTER XII. 
PREGLACIAL DRAINAGE. 


One of the most marked effects of the Glacial period 
was its influence upon drainage systems. The changes pro- 
duced in numerous river-courses of North America by the 
irregular deposits of till and modified drift, as well as by 
the existence of temporary barriers of ice during the con- 
tinuance of the continental ice-sheet, are subjects of unfailing 
interest to the student of physical geography, and are also of 
great practical significance in their relation to the economic 
and hygienic interests of the country. 

As compared with preglacial time, that which has elapsed 
since the close of the Ice age is admitted by all to be very 
short. Consequently, post-glacial erosion is much less than 
preglacial erosion. Before the advent of the continental 
ice-sheet, all the great valleys of North America had been 
sculptured by preglacial streams.* The effects are still to 
be seen even where extensive deposits of the Glacial period 
have partially obliterated them. The sedimentary rocks, 
occupying the basin of the Mississippi, and filling it with 
strata thousands of feet in depth, serve as one index of the 
extent of preglacial erosion; for all the material of this class 
of rocks has been ground up and transported by water. 
Coming down from the neighborhood of the White Mount- 
ains, the Adirondacks, and the Archean highlands of Canada, 
sediment-laden streams have, from the very earliest geologi- 
eal ages, been engaged in wearing away the hills, scooping 


* See Chapter X. 


PREGLACIAL DRAINAGE. 299 


out the valleys, and silting up the sea. The Alleghany 
Mountains were at one time the bed of the ocean upon 
which this sediment was deposited. The sandstones, shales, 
and conglomerates of the coal-measures attest the activity 
of the forces of that early period. The tops of the mount- 
ains in southern New York and northern and eastern Penn- 
sylvania are covered with subcarboniferous conglomerates of 
almost incredible depth and extent, consisting largely of 
well-rounded quartz pebbles, of all sizes up to two or three 
inches in diameter. These are water-worn, and must have 
been rolled along by impetuous currents from far-distant re- 
gions. Thus the tributaries of the Mississippi are, at the 
present time, bringing into its valley similar deposits from 
the mountain plateaus on either side. But no sooner did 
the convulsive forces of the earth begin to lift this great, 
stratified ocean-bed of the Appalachian region above the 
water, than it too became the subject of erosion, and began 
to furnish material for newer deposits farther to the south 
and west. 

The Ohio River and its tributaries furnish a good exam- 
ple of the extent of preglacial erosion. The traveler is im- 
pressed with the gorge in the Niagara River below the falls, 
as showing the force of running water when concentrated in 
a single line of drainage. The gorge of the Niagara, how- 
ever, is only about seven miles long, a thousand feet wide, 
and three hundred feet deep. This, as will appear later,* 
is one of the best measures of post-glacial erosion. But the 
Ohio River, containing a far less volume of water, has worn 
a much larger and deeper trough more than a thousand miles 
in length. The character of the trough of the Ohio and its 
tributaries is readily discerned, even by the passing observer. 
The strata on the opposite sides are horizontal, and match 
each other like the ends of a plank that has been sawed asun- 
der. The alternate layers of conglomerate, coal, shale, and 
sandstone upon the one side of the river correspond to simi- 


* See Chapter XX. 


300 THH ICE AGE IN NORTH AMERICA. 


lar layers on the other side. The width of the gap eut by 
the stream averages about a mile, with enlargements wher- 
ever a tributary comes in from either side. The tributaries, 
also, occupy corresponding narrow valleys of erosion, extend- 
ing even to their very sources in the mountains. The nature 
of the cause preducing these narrow troughs, and its long- 
continued operation in every one of these tributaries of the 
Ohio, are not difficult to see. They have all been formed by 
running water. The Tennessee, the Cumberland, the Ken- 
tucky, the Wabash, the Miami, the Licking, the Scioto, the 
Big Sandy, the Kanawha, the Hocking, the Muskingum, the 
Big Beaver, the Monongahela, and the Alleghany, together 
with their tributaries, all show the vast amount of water- 
erosion along these lines of preglacial drainage. 

But even these do not, in their present condition, reveal 
the whole extent of the effect of the constant and long-con- 
tinued erosive forces of preglacial times. The ancient hed 
of the Obio River was certainly one hundred and fifty feet 
deeper than that over which it now flows, it having been 
filed with glacial débris to its present level. According to 
Professor Newberry— 


At the junction of the Anderson with the Ohio, in Indiana, 
a well was sunk ninety-four feet below the level of the Ohio 
before rock was found. In the valley of Mill Creek, in the 
suburbs of Cincinnati, gravel and sand were penetrated to the 
depth of one hundred and twenty feet below the stream before 
reaching rock. On the margin of the Ohio, at Cincinnati, 
gravel and sand have been found to extend to a depth of over 
one hundred feet below low-water mark, and the bottom of 
the trough has not beén reached. The falls of the Ohio, formed 
by a rocky barrier across the stream, though at first sight 
seeming to disprove the theory of a deep continuous channel, 
really affords no argument against it ; for here, as in many 
other instances, the present river does not follow accurately 
the line of the old channel, but runs along one side of it. At 
the Louisville falls, the Ohio flows over a rocky point which 
projects from the north side into the old valley, while the deep 


PREGLACIAL DRAINAGE. 301 


channel passes on the south side, under the lowlands on which 
the city of Louisville is built. 

The tributaries of the Ohio exhibit the same phenomena. At 
New Philadelphia, Tuscarawas county, the borings for salt-wells 
show that the Tuscarawas is running one hundred and sev- 
enty five feet above its ancient bed. The Beaver, at the jurc- 
tion of the Mahoning and Chenango, is flowing one hundred 
and fifty feet above the bottom of its old trough, as is dem- 
onstrated by a large number of oil-wells bored in the vicinity. 
Oil Creek is shown by the same proofs to run from seventy- 
five to one hundred feet above its old channel, and that chan- 
nel had sometimes vertical and even overhanging walls.* 


Additional particulars of much interest concerning buried 
channels in the Ohio are given by other geologists. For ex- 
ample, Professor Joseph F. James presents cogent reasons 
for believing that the northward bend of the Ohio River, now 
culminating at Cincinnati, continued still farther north pre- 
vious to the Glacial period, and extended through Mill Creek 
up to join the valley of the Great Miami at Hamilton. He 
supposes that the main stream then ran north of the city 
through the valley in which Madisonville is situated. The 
evidence of this is, that below Cincinnati, a short distance, 
the present river flows, beyond all doubt, over bedded rock 
between Price Hill and Ludlow, Ky.; while borings show 
that up Mill Creek several miles the bed-rock lies certainly 
thirty-four feet below low-water mark, while at Hami'ton, 
twenty-five miles north of Cincinnati, the preglacial valley 
is found to be filled up to a depth of more than two hundred 
feet, and the bed-rock lies ninety-one feet below low-water 
mark in the Ohio at Cincinnati.+ : 

Mr. M. C. Read, among other numerous references to 
buried channels, describes one in Knox county, east of Gam- 
bier, in the valley now occupied by Owl Creek, where the 


* “Geological Survey of Ohio,” vol. ii, pp. 13, 14. 
¢ “Journal of the Cincinnati Society of Natural History,” Juiy to October, 
1888, pp. 96-101, and a subsequent personal communication. 


302 THE ICE AGE IN NORTH AMERICA. 


bed-rock lies eighty-two feet below the bottom of the present 
stream. West of Mount Liberty, in the same county, the 
drift conceals an old gorge two hundred and eighty-five feet 
deep.* Mr. P. Max Foshay, in a paper before the American 
Association for the Advancement of Science, in 1888, gives 
many reasons for supposing that Beaver Creek, which now 
empties into the Ohio, was connected by a buried channel 
with Grand River, emptying into Lake Erie at Painesville, 
and hence that a still larger portion of the upper Ohio drain- 
age than was supposed by Mr. Carll passed into the St. Law- 
rence Valley. ‘This suggestion was first made by Professor 
Spencer and indicated on one of his maps over twenty years 
ago. 

Every day is demonstrating that the present level appear- 
ance of the surface of the northwestern portion of Ohio is 
due to the extensive deposits of the Glacial period, whose 
effect has not been so much to make the hills low as to exalt 
the valleys. Professor Orton long ago called attention to the 
numerous buried channels near Springtield in Clarke county, 


one of which is occupied by the New York, Pennsylvania,. 


and Ohio Railroad.t The extensive explorations for stores 
of gas and oil now in progress in the western part of Ohio 
and the eastern part of Indiana are bringing to light buried 
channels in most unexpected places, that at St. Paris, Cham- 
paign county, being more than five hundred feet deep. This 
is an extreme case, but it illustrates what a network of pre- 
glacial gorges have been plastered up by the ice-movement 
which passed over the region. The country resembles, on a 
large scale, a checked and worm-eaten plank which a carpen- 
ter has filled with putty. 

One of the first effects of this fillmg up of the preglacial 
channels has been so to change the lines of superficial drain- 
age, in a great multitude of instances, that the streams are 
now made to run over rocky beds at levels far higher than 


* “Geological Survey of Ohio,”’ vol. ili, pp. 325-347. 
t ‘Geological Survey of Ohio,” vol. i, pp. 450-480. 


———E—E——— re 


PREGLACIAL DRAINAGE. 303 


they had formerly occupied. Thus it is that the glaciated 
region became again a region of waterfalls. Almost every 
stream entering Lake Erie from the south exhibits waterfalls 
produced in this manner. In Minnesota the falls of St. 
Anthony, at Minneapolis, and of Minnehaha, a few miles be- 
low, were thus produced, and, so, are post-glacial in their 
origin, the ancient channels having been filled with glacial 
débris. 

The falls of Niagara are due to the same cause. The pre- 
glacial outlet to Lake Erie was dammed up and buried by 
glacial débris, so that the water was compelled to seek 
another channel. Before the Ice age there was no Niagara 
River, and Lake Erie is, in fact, but a glacial mill-pond. 
The falls of the Genesee at Rochester are also clearly due to 
the same cause. The preglacial valley in the Genesee is now 
deeply buried. “ Between Mount Morris and Rochester the 
river follows its preglacial valley, but flows for much of this 
distance on an alluvial plain that closely resembles the filling 
of an old lake; above and below the limits named the river 
has cut a new channel since glacial times, giving some of the 
best natural sections in the State, and its old course is choked 
with drift.” * 

The falls of the Mohawk at Cohoes, also, doubtless indi- 
cate the existence of a deeply buried channel somewhere in 
the vicinity, connecting, as we shall see a little later, the 
basin of Lake Ontario with the Hudson. 

The evidence that the preglacial outlet of Lake Erie was 
much lower than its present outlet, lies in the fact that sev- 
eral rivers now entering the lake from the south flow at a 
level two hundred feet above that formerly occupied by them, 
since that distance has been penetrated beneath their present 
bottom before reaching rock. From various borings at Cleve- 
land it appears that rock bottom at the mouth of the Cuy- 
ahoga lies more than 500 feet below the level of the lake, 
and is at a depth of at least 200 feet twenty miles in land. 


*See Professor W. M. Davis, in the ‘Proceedings of the Boston 
Society of Natural History,’’ vol. xxi, p. 359. 


304 THE ICE AGE IN NORTH AMERICA. 


Thus, since the elevation of Lake Erie is only 373 feet above 
tide, the rock bottom of the Cuyahoga River, though 700 miles 
inland, is now nearly at sea level. Newberry also discovered 
that Grand and Rocky rivers flow over deeply buried 
channels. In the case of Rocky River, Dr. D. T. Gould has 


Boston Ledges 


= 
re accom! 
—— a ao =. Wey ha 


“ zai 
eae Zo Cuyahoga 
SS BN Drift deposits == Shale 
NL Stugaen? clay 10 Trp area Sand, 


————— 


SSS Shale 


: ATT == 
—_—— ———— = —— 
—S—SSS== a SS SSS SS = 
LSS —————SSSs — 
SS 


traced the buried channel sonthward for a distance of nearly 
thirty miles, or into its upper waters in Medina county. This 
he has done by collecting the record of wells along the route, 
und by noting various places where the present stream crosses 
the old bed, passing out of rocky banks for a short distance, 
and running through clay banks and over a clay bottom to 
enter its new channel again between rocky walls. 

Professor Spencer has also shown, with great probability, 
what was the preglacial line of drainage through which the 
waters, both of Lake Huron and of Lake Erie, flowed to enter 
Lake Ontario on their way to the sea. The line, as he first 
thought, passes out of Lake Huron through the valley of the 
Au Sable, crossing the Thomas River near London, in Canada, 
and entering the basin of Lake Erie a little east of Port Stan- 
ley. Thence, after passing around Long Point and Island, it 
bends northward through the valley of Grand River, and 
enters Lake Ontario at its extreme western point.* From 
later information, furnished me by letter, it appears that Pro- 
fessor Spencer is inclined now to make the connection be- 
tween Lake Huron and Lake Ontario direct, passing through 
Georgian Bay, and reaching Ontario in the vicinity of Toron- 


* “ Second Geological Survey of Pennsylvania,” Q*, pp. 357-406, 


a ee 


PREGLACIAL DRAINAGE. ‘305 


to, as shown in his accompanying map. Thence, according to 
Newberry, the ancient line of drainage passed through On- 
tario, and emerged in a stream occupying the valley of the 
Mohawk, to swell the current of the Hudson rather than 
that of the St. Lawrence.* 

The facts concerning this line of preglacial drainage had 
been thus succinctly stated by Professor Newberry in an ear- 
lier paper : Daa 

Some of the streams draining into the basin of Lake Ontario 
in former times cut their channels below the present ocean- 
level. All the salt-wells of Syracuse are sunk in one of these, 
which is filled with gravel and sand saturated with brine issu- 
ing from the salina group that forms its walls. The rock-bot- 
tom of this old river-bed was reached in some of these wells at 
a depth of fifty feet below the present level of tide-water. 

The valley of the Mohawk is a very deep channel of erosion, 
now half filled, which must have been traversed by a large 
stream flowing eastward at a level below that of the present . 
ocean ; and everything indicates that this was the ancient out- 
let of the basin of the Great Lakes. 

The channel of the Hudson is apparently the only possible 
continuation of this long line of drainage. As has been re- 
marked, it is of great and yet unknown depth. The clay by 
which it is partially filled has been penetrated to a depth of 
about one hundred feet along its margins. How deep it is in 
the middle portion can only be conjectured ; but Hell-Gate 
Channel, which has been kept comparatively free by the force 
of the tides, is in places known to be nearly two hundred feet 
deep ; and, since this is a channel of erosion formed by a stream 
draining into the Hudson, the ancient bed of the Hudson must 
be still lower. + 


The silting up of these preglacial outlets has enlarged 
Lakes Ontario and Huron far beyond their previous limits, 
and wholly created Lake Erie. Lakes Michigan and Superior 


* Paper read before the American Philosophical Society, November 4, 1881, 
p. 93. 
+ “Popular Science Monthly,” vol. xiii, p. 16. 


306 THE ICE AGE IN NORTH AMERICA. 


were likewise greatly enlarged by the damming up of outlets 
which formerly conducted their waters southward into the 
Mississippi. These barriers also turned the surplus waters 
of those inland seas toward the east. The outlet of Lake 
Superior through the rapids of the Sault Ste. Marie is caused 
by the increased depths of the glacial deposits to the west 
across the narrow isthmus separating it from Lake Michigan, 
where, doubtless, a ship-canal could be cut between these two 
lakes without encountering any rocks at all. From the south- 
ern end of Lake Michigan, also, a deeply-buried preglacial 
channel is believed to run southwest, through Kankakee, 
Livingston, and MacLean counties, toward the Mississippi. 
Professor Newberry’s theory of the eastward preglacial 
drainage from the region of Lake Ontario meets with insuper- 
able difficulties, notwithstanding the apparent support it 
would receive from the startling facts recently brought to 
light concerning the depth of the preglacial trough of the 
Hudson River, where the engineers sounding for a foundation 
for a conduit to convey water from the Catskill region to 
New York City in 1906, found that a short distance above 
West Point the rock bottom of Hudson River was 487 feet 
below the present bottom. The depth of the buried channel 
between New York and Newark is not certainly known, but 
the numerous railroad tunnels under the river are uniformly 
through unconsolidated sedimentary deposits, and in case 
of the Pennsylvania road abutments are sunk to a consider- 
able depth in the mud to support the tunnel, as if it were a 
bridge. Outside the harbor of the city this preglacial outlet 
has been traced by the sounding line of the Coast Survey for a 
distance of a hundred miles, to the edge of the deep water of 
the Atlantic. Over aconsiderable portion of this distance it 
has a width of more than a mile and is 2,000 feet deep. These 
facts concerning the Hudson, brought to light since Professor 
Newberry’s death would have greatly strengthened his 
argument. There is, however, one fatal objection to his con- 


PREGLACIAL DRAINAGE. 307 


clusion. At Little Falls, a spur of archaean rocks projects 
from the Adirondack Mountains and effectually separates 
the preglacial drainage of the western part of the state from 
that of the eastern. Professor Newberry had supposed that 
there was room for a deep preglacial channel to lead around 
this obstruction, but fuller examination shows that this 
could not have been the case. The upper part of the St. 
Lawrence is also crossed by continuous strata of archaean 
rocks, showing that there was no preglacial channel permitting 
drainage in that direction. 

To a superficial observer it would seem that the way was 
equally closed into the Mississippi Valley. For it would 
appear in the highest degree unlikely that the drainage of 
Lake Ontario, whose bottom is now 507 feet below tide 
level, could ever have found a way across the intervening 
highlands which separate it from the Mississippi Valley, the 
lowest place of which (at Chicago) is more than 600 feet above 
tide level. But our conception of the depth of the glacial 
deposits over this intervening area, and of the preglacial 
gorges that have been filled by them has been enormously 
enlarged by every fresh investigation of the region. 

The course of preglacial drainage in the upper basin of 
the Allegheny River is worthy of more particular mention. 
Mr. Carll, of the Pennsylvania Geological Survey, has conclu- 
sively shown that previous to the Glacial period the drainage 
of the valley of the upper Allegheny north of the neighbor- 
hood of Tidioute, in Warren county, instead of passing south- 
ward, as now, was collected into one great stream flowing 
northward through the region of Cassadaga Lake to enter the 
Lake Erie basin at Dunkirk, N. Y. The proof of this is that 
between Tidioute and Warren the present Allegheny is shal- 
low, and flows over a rocky basin; but from Warren north- 
ward, along the valley of the Conewango, the bottom of the 
old trough lies at a considerably lower level, and slopes to 
the north. Borings show that in thirteen miles the slope of 


308 THE ICE AGE IN NORTH AMERICA. 


the preglacial floor of Conewango Creek to the north is 136 
feet. The actual height above tide of the old valley floor at 
Fentonville, where the Conewango crosses the New York line, 
is only 964 feet; while that of the ancient rocky floor of the Al- 
legheny at Great Bend, afew miles south of Warren, was 1,170 
feet. Again, going nearer the head waters of the Allegheny, 
in the neighborhood of Salamanca, it is found that the ancient 
floor of the Allegheny is, at Carrollton, seventy feet lower than 
the ancient bed of the present stream at Great Bend, about 
sixty miles to the south; while at Cole’s Spring, in the neigh- 
borhood of Steamburg, Cattaraugus County, N. Y., there has 
been an accumulation of 315 feet of drift in a preglacial valley 
whose rocky floor is 155 feet below the ancient rocky floor at 
Great Bend. There must, therefore, of necessity have been 
some other outlet than the present for the waters collecting 
in the drainage-basin to the north of Great Bend. 

- While there are numerous superficial indications of buried 
channels running toward Lake Erie in this region, direct ex- 
ploration has not been made absolutely to demonstrate the 
theories. But, if resorted to, we know, from the facts just 
stated, that the line of some such drainage valley must be dis- 
covered. In the opinion of Mr. Carll, Chautauqua Lake did 
not flow directly to the north, but, passing through a channel 
nearly coincident with that now occupied by it, joined the 
northerly flowing stream a few miles northeast from James- 
town.* It is probable, however, that Chautauqua did not 
then exist as a lake, since the length of preglacial time would 
have permitted its outlet to wear a continuous channel of 
great depth corresponding to that known to have existed in 
the Conewango and upper Allegheny. 

Farther west as already shown, the Middle Allegheny 
appears to have followed a channel leading past Meadville 
through French Creek to the Lake in the vicinity of Erie, 
Pa., while the drainage of the Monongahela was clearly north- 
ward through Beaver Creek and the Mahoning and Grand 


* “Second Geological Survey of Pennsylvania,’’ iii. 


PREGLACIAL DRAINAGE. 309 


River valleys to Lake Erie, a little west of Ashtabula. This 
was demonstrated by Mr. Hice, who discovered pot-holes 
on the rock terraces of Beaver Creek all pointing northward. 
This line of preglacial drainage of the Upper Ohio has been 
chosen by the engineers as the best route for the canal to 
connect Lake Erie with the Ohio Valley. ‘The portion of the 
Upper Ohio following this line in preglacial times is that above 
Martinsville, where there is a well marked narrow place in 
the gorge indicating a preglacial col between two systems of 
drainage. The water, being thrown over this by the glacial 
dam, speedily eroded a channel such that upon the melting 
of the ice the water continued to flow in that direction. 

According to the investigations of Professors Tight and 
Bownocker, it would seem, also, that thedrainage of the Middle 
Ohio was through buried channels leading to the northwest, 
along a line nearly coinciding with the valley of the Scioto. 
As will be detailed more fully in another chapter (p. 379, 
seq.) the Middle Ohio, below Martinsville flowed southwest 
as far as Huntington, West Virginia, where it was joined by 
the Kanawha, a still larger stream coming down from the 
Appalachian Mountains through the deserted channel of 
Teazes Valley. At Huntington the united current turned 
northward to the vicinity of Portsmouth at the mouth of the 
present Scioto, where it was met by a shorter stream flowing 
eastward from a col in the Ohio at Manchester. Ten miles 
above Portsmouth, at Wheelersburgh the Little Scioto enters 
the Ohio after having flowed for many miles through a broad 
abandoned channel, which near the village of California 
inosculates with another running northwestward into the 
Scioto at Waverly. It is the opinion of Mr. Leverett, and of 
Professors Tight and Bownocker, that the Kanawha drainage 
in preglacial times took this course, and then proceeded ina 
northward direction through the buried channel of the Upper 
Scioto. 

A little below Columbus this stream was joined by one 


310 THE ICE AGE IN NORTH AMERICA. 


emerging from the Tuscarawas Valley through a clearly 
marked buried channel leading from one valley to the other 
at Newark. At the present time the Tuscarawas drainage 
turns a right angle at Dresden and flowing south to Zanes- 
ville is joined by the Licking River coming from the north- 
west, and both flow southward through a narrow, and clearly 
post-glacial valley to the Ohio at Marietta. 

The whole country north of Columbus is so deeply covered 
with glacial drift that it isimpossible to trace the preglacial 
drainage except through the aid of borings which have been 
made in search of artesian water, or of gas and oil. But these 
have revealed so many deep cafions, in some cases more than 


? (hen 
River Hot 


aaa coe ol cae 


i A ES EE CE OS es SY SS 


Fig. 95—Cross-section from Sonora, Illinois, to Argyle, lowa, showing old and new chane- 
nels of the Mississippi River. (From Iowa Geological Survey.) 


500 feet in depth, that it is by no means impossible, or even 
improbable that the whole drainage led off into the Wabash 
Valley, or perhaps more directly north into the bed of Lake 
Erie, and so around inte the Wabash or Illinois. 

The preglacial drainage of the Lower Ohio is equally inter- 
esting. As already shown, and as appears graphically in the 
map on p. 643, the Licking River of Kentucky continued 
north from Cincinnati through the valley of Mill Creek, hav- 
ing been joined at Ivorydale by that portion of the preglacial 
Ohio which came from the col below the mouth of the Scioto. 
This united stream, after reaching Hamilton, probably turned 
southward through the channel of the Great Miami, which is 
much broader than that of the Ohio just below Cincinnati. 
Below Lawrenceville, Indiana, there has been littie change in 


PREGLACIAL DRAINAGE. dll 


the course of the river since preglacial times except in the 
vicinity of Louisville, Kentucky, where it now flows over a 
rocky barrier constituting the Falls which obstruct navigation 
at this point. There is, however, a deeply buried channel 
south of Louisville filled with the coarser silt bought down by 
glacial floods from the melting ice which reached and crossed 
the river for some distance above. 

Coming to the Mississippi River two preglacial channels 
are of special interest. Cne lies just west of Minneapolis, 
- following a wide shallow depression dotted with small lakes 
and entering the valley of the Minnesota a short distance 
above Fort Snelling, where the present Mississippi joins the 
valley. This preglacial gorge is now filled with glacial débris 
to a depth of 200 feet or more. The present Mississippi 
after plunging over the Falls of St. Anthony occupies a narrow 
rocky gorge, which it has worn since glacial times, to its 
junction with the main valley. 

A similar broad, deep preglacial valley channel of the 
Mississippi now filled with glacial débris is found west of 
Keokuk, Iowa. This became so completely filled with till 
that the river was forced to seek its present channel, which 
passes over rocky rapids at Keokuk, compelling the govern- 
ment to construct there a canal with locks for the sake of 
navigation. (See Fig. 95). 

In Professor I. C. White’s report upon Pike and Monroe 
counties, Pennsylvania,{ he gives an account of no less than 
twenty-three channels which have been buried by glacial 
débris. Among these that of the Wallenpaupack Creek is 
the most striking. At present this creek empties into the 
Lackawaxen at Paupack Falls, where it descends 260 feet in 
a mile. But on ascending the creek two or three miles, to 
the vicinity of Tafton, the course of a preglacial valley can 
be easily recognized, leading into Kimball’s Run, and join- 
ing the Lackawaxen at Kimball’s Station. This channel is 


{Ibid, G®, pp. 52-63. 


pies THE ICH AGE IN NORTH AMERICA. 


now buried to a depth of 300 feet for a distance of many 
miles. | 

R. W. Ells calls attention, also, to the numerous buried 
channels* in the Eastern Townships, in the province of Que- 
bec, in the vicinity of Lake Memphremagog. These are, to 
a considerable extent, explored at the present time for the 
sake of the gold found in them. 

These are but a few of the innumerable facts indicating 
that before the great Ice Age not only the Ohio, but nearly 
all the streams of the eastern United States, occupied deeper 
channels than they now do. There were then probably no 
Great Lakes, and few if any waterfalls, as there are now no 
lakes and waterfalls south of the glaciated region. All the 
rivers had cut their channels down so low that they drained 
to the bottom any lakes that may have once existed. 


i “Annual Report of an Geological and Natural History Survey of 
Canada,’’ vol. ii, 1866, p. 49, J. 


.! 
¥ 
2h 


T= 


| \ ‘ 


MAP SHOWING, IN DOTTED LINES, 


Detroito 


San, dusky 


72104 67 40 57 


19 106 


~ 


50 


Kincardine 


20-30 37 54/ 


5 20 30 35 


37 218 


‘45 815 


Goueri 


8 2028 95 81/32 15 3 


20 


10 


20 
10 
Ss 
s 
Sable 


THE PREGLACIAL DRAINAGE IN THE BASIN OF 
THE LOWER GREAT LAKES. 
Corrected, according to the latest information, 
by Professor J. W. SPENCER 
SCALE OF MILES 


Ai) 75 100 


1b 25 


NOTE: The figures in the lakes give the 
depth of water in fathoms of six feet each. 


20 
ry ne 1 


dh 


Struthers § Co., Engrs, NK. 


CHAPTER XIII. 
DRAINAGE OF THE GLACIAL PERIOD. 


Dering the continuance of the Ice age, an extraordinary 
factor was in the field to modify the lines of drainage, and 
to give to them both a direction and a character such as they 
never had had at any other time. Throughout the whole ex- 
tent of the Glacial period the ice itself was a most important 
barrier, deflecting the course of the streams, and, at the same 
time, was a cause of irregularity in the volume of water 
such as is altogether unique in the history of the world. The 

vast mass of frozen water then stored up at a high level was 
an immense reservoir of force, ready, on proper conditions, 
: to descend in torrents through any channel which was opened 
before it. 
As the ice of the Glacial period advanced southward from 
the Laurentian highlands, it reversed the currents of all the 
’ great rivers which flowed to the north. One of the first and 
. most remarkable effects of this advance must have been the 
damming up of Nelson River, so as to cause the surplus 
water—ordinarily flowing through Hudson Bay into the 
North Atlantic—to pour over into the head-waters of the 
Mississippi and so into the Gulf of Mexico. Thus, from the 
beginning of the Glacial period to its close, the Mississippi 
River must have been the channel through which was carried 
off the waste water from the larger part of the Dominion of 
Canada as well as from the central portion of the United 
States. A little later, also, the drainage of the Great Lake 
region must have been obstructed toward the northeast and 
east; for, long before the eastern lobe of the glacier had 


314 THE ICE AGH IN NORTH AMERICA. 


reached the latitude of New York city, the valleys of the St. 
Lawrence and of the Mohawk must have been closed up by 
ice so as to reverse their lines of drainage. The waters of 
Lakes Superior and Michigan must then have flowed into the 
Mississippi River along the lines of the Fox, Wisconsin, and 
Illinois Rivers, while those of Lakes Huron and Erie poured 
into the Ohio River, at first down the Wabash, then, a little 
later, when the extension of the central lobe of ice cut off the 
western outlet of Lake Erie, over the lowest places in the 
water-shed into the valleys of the Scioto, the Muskingum, 
and Beaver Rivers; at the same time, every northern tribu- 
tary of the Alleghany was a glacial flood. 

But the scenes to have been witnessed during the ad- 
vance of the ice-sheet are as nothing compared with those 
which must have occurred during its retreat. Even now, 
every spring has its freshets, when the combined action of ice 
and water produces floods unparalleled at other seasons of the 
year. If this is the case upon the melting of the small amount 
of snow which annually accumulates in our present winters, 
the floods at the breaking up of the Glacial period itself 
must have been inconceivably great. With every recurring — 
spring we now look in the telegraphic summary for thrilling 
accounts of ice-gorges formed in the St. Lawrence, the Dela- 
ware, the Susquehanna, and the Missouri River. By reason 
of these gorges, and their accompanying destructive floods, 
Port Jervis, on the Delaware, and Mandan, on the Missouri, 
have become familiar names. Reasoning from the nature of 
the case, what, then, must have been the scenes during the 
last stages of the great Ice age, when, through the months 
of July, August, and September, warm southerly winds and 
a glowing sun were combining to dissolve, with utmost ra- 
pidity, the vast masses of ice which still lingered in the 
country! The channels were then compelled to carry off 
not only the annual precipitation, and the torrents of an oc- 
easional cloud-burst, but the stored-up precipitation which 
had been accumulating as glacial ice for thousands of years. 

Nor is this altogether theoretical. Though we have no - 


DRAINAGE OF THE GLACIAL PERIOD. 315 


telegraph to span the distances of time separating us from 
those events, we have come into possession of signs as intel- 
ligible as the lines and dots of the Morse alphabet, and even 
more trustworthy. These floods along the lines of glacial 
drainage have left their marks, and their direction and ex- 
tent can be traced almost as readily as in the case of the 
present streams. 

Ascending the channel of the Mississippi above its junc- 
tion with the Ohio, one enters a region where it is bordered 
on each side by rocky bluffs, and finds himself in a valley of 
erosion whose main features were determined in preglacial 
times. Above Grand Tower, in southern Lllinois, and as far 
north as St. Louis (a distance of about one hundred and fifty 
miles), the extreme margin of glacial deposits rests upon the 
east side of the river, and an unglaciated region is upon the 
west ; the width of the eroded valley being from five to ten 
miles, and its depth several hundred feet. Above St. Louis 
the valley gradually narrows, though it is still from two to 
eight miles in width, and about the same depth as below the 
city. At various places, along the sides of this eroded val- 
ley, the observer will find gravel terraces one or two hundred 
feet above the present flood-plain. These terraces are, in 
fact; the high-water mark of the closing floods of the Ice age. 

But the culmination of interest is reached on coming to 
the present junction of the Minnesota and Mississippi Riv- 
ers near St. Paul. From Fort Snelling, just above St. Paul, 
northward, the present Mississippi River is a comparatively 
recent stream, occupying a post-glacial bed. The true exten- 
sion of the trough of the Mississippi follows up the Minne- 
sota River. The gorge of the Mississippi, leading from Fort 
Snelling up to Minneapolis, is scarcely a quarter of a mile in 
width, and is about two hundred and fifty feet in depth ; 
while the trough of the Minnesota is from one to four miles 
in width, and its rocky bottom is more than one hundred and 
fifty feet lower than the present bed of the stream. In the 
bottom of this broad valley, for a distance of two hundred 
and fifty miles, the Minnesota River wanders about from 


316 _THE ICE AGE IN NORTH AMERICA. 


side to side as a very insignificant thing, entirely out of pro- 
portion to the valley which it occupies. Nor does the Min- 
nesota River have its sources in the highlands, like the Mis- 
sissippl. Its head is in Big Stone Lake, in the midst of this 
eroded trough, and but a few miles south of Lake Traverse— 
the head of the Red River of the North—also in the same 
trough and on the same absolute level. The water from Lake 
Traverse sometimes flows into the other lake. In short, the 
troughs of the Minnesota and the Red River of the North 
are one and continuous, and the depression joining them, 
known as Brown’s Valley, is to the glacialist one of the most 
interesting spots on the continent. The following is Mr. 
Upham’s description : 


Lakes Traverse and Big Stone are from one to one and a 
half mile wide, mainly occupying the entire area between the 
bases of the bluffs, which rise about one hundred and twenty- 
five feet above them. Lake Traverse is fifteen miles long ; it 
is mostly less than ten feet deep, and its greatest depth proba- 
bly does not reach twenty feet. Big Stone Lake is twenty-six 
miles long, and its greatest depth is reported to be from fifteen 
to thirty feet. The portion of the channel between these lakes 
is widely known as Brown’s Valley. As we stand upon the 
bluffs here, looking down upon these long and narrow lakes in 
their trough-like valley, which extends across the five miles 
between them, where the basins of Hudson Bay and the Gulf 
of Mexico are now divided, we have nearly the picture that 
was presented when the melting ice-sheet of British America 
was pouring its floods along this hollow. Then the entire ex- 
tent of the valley was doubtless filled every summer by a river 
which covered all the present areas of flood-plain, in many | 
places occupying as great width as these lakes. * 


Among the most interesting facts concerning the drainage 
lines of the glacial period are those connected with the 


* “ Proceedings of the American Association for the Advancement of Sci- 
ence,” vol. xxxii, 1883, pp. 216, 217. This glacial outlet through Brown’s Val- 
ley and the Minnesota has been fittingly named, by Mr. Upham, River Warren, 
after General G. K. Warren, who first described it. See map in Chapter XXL 


DRAINAGE OF THE GLACIAL PERIOD. 317 


advance and recession of the ice from the basin of the Great 
Lakes. As the advancing ice closed up the outlets leading 
into the St. Lawrence Valley the drainage was successively 
turned through Lake Champlain into the Hudson. A little 
later it was turned around the Adirondacks through the 
Mohawk River Valley into the Hudson. Later still it was 
turned over into the Susquehanna through the fissures now 
occupied by the Finger Lakes of Central New York. A still 
farther advance turned the vast current through the valley 
occupied by the Grand, Mahoning and Beaver rivers into the 
head-waters of the Ohio and helped in the formation of its 
present tortuous channel. 

Meanwhile the advance of the ice farther west was produc- 
ing numerous changes in the drainage of the upper lake region. 
At first the drainage of Lakes Erie and Huron was turned 
through the straits of Mackinaw into Lake Michigan and ran 
off through the line of the present drainage canal into the 
Mississippi through the Illinois River. Then, as soon as the 
eastern endof Lake Superior was closed up, the drainage from 
the western portion was through the St. Croix River at an 
elevation of 466 feet above the lake into the Mississippi a 
little below St. Paul. With the advance of the ice a little 
further into the southern peninsula of Michigan the channel 
through the Straits of Mackinaw was closed, forcing the water 
over a low col leading from Saginaw Bay into the head-waters 
of Grand River, and thence into Lake Michigan a short 
distance below Grand Rapids, and so again over the line of 
the Chicago drainage canal into the Mississippi basin. 

A still further advance closed up the entire passage into 
Lake Michigan and turned the drainage southward from 
Toledo, Ohio, through the pass at Fort Wayne, Indiana, into 
the Wabash River and thence into the Ohio. 

Of course the direct evidence of these facts is not now 
available, since the advancing ice has obliterated the beaches 
and terraces which were built up before it. But on the retreat 


‘ Priatleas 
ta 


“ROBLES € OTT 


>fo 
. 


yh i 

2 -* — ee ore ty 
Werrtwe BN Ni heels 
6 = 


-DRAINAGE MAP 


, Or 
SOUTHEASTERN 


IOWA 
by 


Frank Leverett. 
1901 


jpenle of Miles sp 


Le s <F 


Fig. 97.—Cross section of the Osage trough at Tuscumbia, Mo., with a Canadian 
bowlder on the upper terrace above the flood plain. (See p. 321). 


ee et ae 


DRAINAGE OF THE GLACIAL PERIOD. 319 


of the ice these lines were opened in reverse order and shore 
lines and abandoned channels were left for inspection for all 
time. These abandoned channels and the bordering high- 
level gravel terraces are clearly marked through the line of 
the St. Croix River in Wisconsin, through the line of the Chi- 
cago drainage canal, through the pass at Fort Wayne and 
along the whole course of the Wabash River in Indiana, and 
to a greater or less extent through the other passes which 
were occupied by the reversed glacial floods for a shorter 
time further east. The shore lines of the temporary glacial 
lakes whose levels were determined by the height of these 
several passes are also clearly marked around the west end of 
Lake Superior in the terraces above Duluth; and around 
the southern shore of Lake Erie where at three levels already 
mentioned they lead to Fort Wayne, at an elevation of 200 
feet above the present level of the lake, and from Saginaw Bay 
at levels of 150 and 100, respectively, to the upper and the 
lower passes into Grand River, Michigan. 

Mr. Frank Leverett discovered a most interesting dis- 
placement of a middle portion of the Mississippi River dur- 
ing the farthest advance of the Illinoisan ice-sheet, which 
pushed across the river for an average distance of from 
thirty to forty miles between Clinton and Keokuk. This 
forced the drainage along the border of the ice-sheet through a 
channel stil! clearly marked through Jackson, Clinton, Scott, 
Muscatine, Louisa, Des Moines, Henry, and Lee counties, 
a distance of about 150 miles. But on the retreat of the ice, 
the present channel was opened. 

Gravel terraces of great prominence also mark the course 
of final glacial drainage through the Mohawk River in Cen- 
tral New York, and a shore line around the southern side of 
Lake Ontario is distinctly traceable from the mouth of the 
Niagara gorge to the col at Rome, leading from the Ontario 
basin into the Mohawk. 


320 - THE ICE AGE IN NORTH AMERICA. 


Another striking deposit of this final glacial drainage can 
be seen on the eastern flank of the Adirondack Mountains 
at Chazy, a few miles west of Plattsburgh, where there is a 
large and most remarkable accumulation of rolled river 
pebbles two or three hundred feet above the level of Lake 
Champlain, while there is no stream .bed anywhere near 
this locality. The only explanation of it is (and it is entirely 
adequate), that this was a line of temporary drainage for the 
glacial floods which for a time accumulated in the upper 
St. Lawrence Valley and found their only passage for a while 
between the mountain mass of the Adirondacks and the wan- 
ing ice which filled the Champlain Valley. (For an illustra- 
tion from Alaska, see Plate VIII.) 


From the Missouri Valley there come some of the most 
startling facts revealing the extent of the floods which charac- 
terized the later stages of the glacial period. The present 
Missouri discharges (according to Humphreys and Abbott) 
twenty-nine cubic miles of water annually. Yet, even so, 
there are frequently floods in the lower part of the valley 
which reach a height of thirty or forty feet above present 
low water mark. But at the time of the greatest extent of 
the ice-sheet the drainage of not far from 250,000 square 
miles of ice covered area found its way into the Middle Mis- 
souri. For a considerable time towards the close of the 
glacial epoch the ablation of this ice would, at a moderate 
estimate, amount to ten feet per annum over this whole 
contributory surface. This would furnish 500 cubic miles of 
additional water to be carried off through the lower portion 
of the river channel during each summer between April and 
November. An examination of the lower channel shows that 
at Hermon twenty-five miles below the mouth of the Osage 
River where it joins the Missouri the passage between rocky 
bluffs 300 feet high is barely two miles wide. Mathematical 
calculations will show that it would require ninety-six days 
for a current two miles wide and two hundred feet deep, flow- 


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pe 


DRAINAGE OF THE GLACIAL PERIOD. O21 


ing at the rate of three miles an hour, to carry off this surplus 
drainage of 500 cubic miles accumulating each summer. 

If it should be supposed that the current would be much 
faster than three miles an hour, it is proper to note that 
from the known facts about the northerly depression of the 
land during the latter part of the glacial period it is extremely 
probable that the gradient of the stream was very much 
less during the time of these floods than it is now. Further- 
more, the gradient of the stream was much diminished by the 
flooded condition of the Mississippi into which the Missouri 
enters. For, the glacial floods pouring into the Mississippi 
and Ohio were of such enormous magnitude as probably to 
raise the level of the Mississippi 100 feet or more, during these 
summers. It is not at all unreasonable, therefore, to expect 
to find indications of glacial floods in the Lower Missouri 
rising to a height of 200 feet or more. 

And these we do find. In 1902, Dr. Ball of the Missouri 
Geological Survey found anumber of large Canadian bowlders 
in the valley of the Osage River sixty miles above itsjunction 
with the Missouri and forty miles south of the extreme limit 
of the extension of glacialice. There is no way to account for 
such bowlders in that position except on the supposition 
that they were floated in there by a backward current from 
the Missouri when its glacial floods, bearing floating masses of 
ice with Canadian bowlders upon their surface, reached a 
height of 200 feet. Since there was no melting ice in the valley 
of the Osage to increase its volume, such an eddy in the cur- 
rent would be sure to set up that valley and supply the cause 
necessary to explain what was a very puzzling problem when 
first propounded. Such floods also are needed in the Missouri 
Valley to account for the many level-topped extensive accu- 
mulations of loess (a fine river loam to be described more in 
detail in a later chapter) which occur at numerous points 
throughout the valley. 


Pear fae 
En 


Fia. 98.—The unshaded portion shows the glaciated area; but at Tuscumbia numerous 
Canadian bowlders are found in the upper gravel terraces bordering the Osage river. 
(See fig. 97, p. 318.) These could have come into this place only by the agency o 
bere water bearing ice floes from the glacial floods of the Missouri as described in 

the text. 


DRAINAGE OF THE GLACIAL PERIOD. 323 


The high level gravel terraces so constantly lining 
the water-courses in the Middle and Western States, and 
which formerly were attributed to the advance into these 
regions of the waters of the ocean, are readily accounted for 
by the action of the torrents set free by the melting of the 
ice during the closing years of the great Iceage. One of the 
striking confirmations of the glacial theory appears in the 
absence of terraces in the valleys of such minor streams as 
have their sources south of the glacial limits. For example, 
in Ohio the small streams in the southeastern part of the 
State, whose sources are outside of the glacial limits, present 
a marked contrast to the other streams of the State flowing 
south, as do also the streams flowing to the north and empty- 
ing into Lake Erie. The troughs of the Wabash, the two 
Miamis, the Scioto, the Hocking, and the Muskingum, with 
their tributaries, are all lined by gravel terraces, rising from 
fifty to one hundred and fifty feet above the present flood- 
plains, showing the enormous volume of the streams which 
flowed through them at the close of the period. The coarse- 
ness of the material in these terraces also bears witness to the 
violence of the currents. But between the mouth of the 
Muskingum, at Marietta, and the mouth of the Little Beaver, 
the streams entering the Ohio are devoid of terraces, the ex- 
planation being that their sources lie outside of the glaciated 
limit, so that they had access neither to the accumulations of 
the glacial deposits, which furnished material for the terraces, 
nor to the floods of water that distributed it. To the east- 
ward, again, upon striking the streams whose drainage-basins 
lie within the glaciated limit, high terraces, containing north- 
ern pebbles brought from beyond the water-shed, begin again 
to appear, both along the margins of the streams in the gla- 
ciated area, and also through their whole course below the 
boundary. In the matter of terraces, likewise, the northern 
tributaries of the Ohio are in striking contrast with the 
southern. 

Kast of the Alleghanies the same contrast appears between 
the streams rising within the glaciated area and those outside 


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DRAINAGE OF THE GLACIAL PERIOD. 329 


of it. The terraces on the East Branch of the Susquehanna are 
much more marked than those upon the West Branch, the 
explanation being that the East Branch lies almost wholly 
within the glaciated area, while only a few of the minor tribu- 
taries of the West Branch come down from it. But wherever 
they do so come, as in the case of Pine, Lycoming, and Loy- 
alsoek Creeks, a limited amount of drift from the far north 
is distributed along their banks, and deposited at their junc- 
tion with the main branch of the river. The Lehigh and the 
Delaware are likewise marked by high terraces containing 
pebbles from the far north, while the Schuylkill River, which 
lies just outside of the Placiaccd limit, has no such terraces. 
Thus, both by the method of agreement and of difference, we 
prove the connection of these terraces of the so-called “ Ter- 
race epoch” with the gorged and gravel-laden streams of the 
great Ice age. 

Before speaking of the lines of glacial drainage farther 
east, it will be profitable to direct our attention to another 
ess of closely connected facts confirming the theory of the 
glacial origin of these terraces. The larger part of the ma- 
terial contained in them is derived from the glacial deposits 
over the region through which the several streams flow. The 
hard fragments of granite, quartzite, and various metamorphic 
rocks from the region of Lake Superior and the Canadian. 
highlands are eminently fitted to withstand abrasion, and can. 
be rolled by a torrent for long distances before being ground 
to powder, while the softer sandstones and shales of the newer 
geological formations would be comminuted by the attrition 
of a comparatively few miles’ travel. Hence it comes about 
that the terraces of the Middle States are composed, in a pre- 
dominant measure, of material brought over the water-shed 
by the ice from the far north, and spread broadcast over the 
country, and thence collected by the streams of water and 
rolled along as far to the south as there was force in the cur- 
rent to move them, or through as great a distance as the 
hardness of the material of which they are composed would 
enable them to resist complete attrition. There is no more 


326 THE ICE AGE IN NORTH AMERICA. 


interesting verification of an hypothesis anywhere to be found 
than that furnished for the. glacial theory through the study 
of the character of some of these terraces at and below the 
glacial limit. Theoretically the terraces should, for the rea- 
sons just stated, be more prominent and consist of coarser 
material, just where the streams emerge from the glacial 
limit ; and such, from a wide collection of facts, is proved to 
be the rule. I have myself examined nearly ali the streams 
thus emerging from the glaciated area between the Atlantic 
Ocean and the Mississippi River.* In scores of places where 
streams thus emerge from the glaciated region—in Pennsyl- 
vania, Ohio, and Indiana-—their valleys are filled with an 
accumulation of water-worn northern drift, which, when fol- 
lowed downward, becomes gradually less in amount, as well 
as more water-worn, and finer in its constituent elements. 

This is notably the case in the Delaware Valley, at Belvi- 
dere, N. J.; in the Susquehanna, at Beach Haven, Pa.; in 
the Conewango (as already described), at Ackley, Warren 
county; in Oil Creek, above Titusville; in French Creek, 
a little above Franklin ; in Beaver Creek, at Chewtown, Law- 
rence county; on the Middle Fork of Little Beaver, near 
New Lisbon, Ohio; on the east branch of Sandy Creek, at 
East Rochester, Columbiana county; on the Nimishillin, at 
Canton, Stark county; on the Tuscarawas, at Bolivar; on - 
Sugar Creek, at Beech City ; on the Killbuck, at Millersburg, 
Holmes county; on the Mohican, near the northeast corner 
of Knox county; on the Licking River, at Newark; on 
Jonathan Creek, Perry county; on the Hocking, at Lancas- 
ter; on the Scioto, at Hopetown, just above Chillicothe; on 
Paint Oreek, and its various tributaries between Chillicothe 
and Bainbridge; and on the Wabash, above New Harmony, 
Ind.; to which may be added the Ohio River itself, at its 
junction with the Miami, near Lawrenceburg. 

Some of these instances are sufficiently interesting and 


* “@Glaciated Area of Ohio,” in the “American Journal of Science,” vol. 
exxvi, 1883, pp. 1-14; “ American Naturalist,” vol. xviii, pp. 755-767. 


DRAINAGE OF THE GLACIAL PERIOD. 327 


instructive to warrant a special description. The upper part 
of the Ohio River, between Pittsburg and New Richmond, 
in the vicinity of Cincinnati, lies entirely outside of the gla- 
ciated area, while nearly all of its northern tributaries rise 
within that area. In the happy phraseology of Professor 
Dana, the Ohio River becomes, therefore, the great distribu- 
ter, while its northern tributaries are the principal contribu- 
tors, of terrace material. Now, it is observable that, wherever 
a large contributor of drift material comes in from the north, 
there is a great increase in the extent and height of the ter- 
races for some distance below, and the material of which the 
terrace is composed is coarser at these points. Tor example, 
in the neighborhood of Cincinnati, the Ohio is joined by the 
Little Miami, and twenty miles below, at Lawrenceburg, by 
the Great Miami. Throughout their entire course these 
tributary streams flow through a region deeply covered with 
glacial deposits. As a consequence, the terraces here are of 
great height and width. At Cincinnati, the upper terrace 
upon which the original city is built is one hundred and 
twenty feet high; and at Lawrenceburg the valley, from 
three to four miles wide, is nearly filled to a height of one 
hundred and twelve feet above the flood-plain, with a ter- 
race deposit clearly derived from the glacial floods of the 
Great Miami and its tributaries. Below this point the ter- 
races of the Ohio gradually diminish in height, and the ma- 
terial becomes finer, and more and more water-worn. Above 
Cincinnati there is a marked development of the terraces at 
the mouth of the Scioto, at Portsmouth; and again, below 
Marietta, at the mouth of the Muskingum, where, opposite 
Blennerhassett Island, the terraces are in the neighborhood 
of one hundred feet above the present low-water mark. It 
is to be noted that both of these streams were so situated as 
to be among the largest contributors to the Ohio, both of 
glacial floods and glacial débris. 

But the most instructive place for the observation of this 
class of phenomena is to be found in Pennsylvania, at the 
junction of Beaver Creek with the Ohio River. From the 


328 THE ICE AGH IN NORTH AMERICA. 


mouth of French Creek, at Franklin, Pa., to the mouth of 
Beaver Creek, twenty-five miles below Pittsburg, a distance 
of about one hundred and fifty miles, no contributors of gla- 
cial material enter the Alleghany or the Ohio River, and the 
course of the river-bed lies wholly in the soft, sedimentary 
deposits of the coal-measures. Consequently, while this por- 
tion of the stream contains terraces with northern drift 
brought into the Alleghany above Franklin, they are of 
diminishing height, and contain a constantly diminishing 
amount of material from the glacial drift all the way down 
to the mouth of the Beaver. 

At the mouth of the Beaver there is a sudden enlarge- 
ment of the Ohio terrace, and it rises at once to a height of 
one hundred and twenty feet above the river. Upon the 
lower side of the Beaver, in the angle between it and the 
Ohio, down-stream, this terrace is very extensive, and the 
material very coarse, the terrace being, indeed, largely built 
up of pebbles and bowlders from a few inches to two feet 
or more in diameter, and all thoroughly rounded. On the 
opposite side of the Beaver, in the angle between its mouth 
and the upper portion of the Ohio, there is, for a limited 
distance, a terrace of equal height, but of entirely different 
composition from that upon the lower side. The terrace 
upon the upper side consists of fine material, being mostly 
sand and gravel derived from the coal-measures, through 
which the Ohio itself has cut its way. Pebbles from the 
northern drift are rare, and the local origin of the material 
is manifest at a glance. What, now, makes this difference 
between these terraces upon the opposite sides of this small 
tributary of the Ohio? A glance at the map will show.* 

The Beaver River emerges from the glaciated region only 
a few miles to the north of its junction witb the Ohio. The 
larger part of its drainage-basin lies in portions of northeast- 
ern Ohio and northwestern Pennsylvania, which are deeply 
covered with the terminal deposits of the continental ice- 


— 


* See map, p. 145. 


DRAINAGE OF THE GLACIAL PERIOD. 329 


sheet. The floods characterizing that period had access to 
an unlimited amount of material, which was easily swept into 
the current, and rolled down the torrential bed toward the 
Ohio River. Upon reaching the Ohio, the combined cur- 
rent of the two streams in the larger valley would have far 
less power of transportation than the constricted current in 
the channel of the glacial tributary. The bowlders would, 
therefore, be deposited at the mouth of the Beaver, where it 
joins the Ohio, and, owing to the influence of the current of 
the Ohio itself, would be carried below the junction of thf 
two rivers. Hence it is that we find so many glacial bowl- 
ders below the junction, and so few above it. The accumu- 
lation of a terrace of an equal height above the junction, but 
consisting of fine and local material, is also what would be 
required by theory as well as what is found to be the case in 
fact. Thus we have, in this single instance, one of the best 
possible verifications of the glacial hypothesis. 

Of the glacial terraces on the Delaware River, from the 
Water-Gap to Trenton, N. J., there will be occasion to speak 
more fully when treating of the subject of man’s relation 
to the Ice age in North America. Nor can we more than 
allude to those which line the Mohawk and the troughs of the 
Hudson and its tributaries. It is sufficient to say that the 
passengers upon the New York Central Railroad can satisfy 
themselves of the existence of these terraces east of Little 
Falls, N. Y., and between Schenectady and Albany, by 
merely looking out of the car-windows toward the north; 
and a moment’s reflection upon the topography of the coun- 
try will show that the terraces of the Mohawk and the up- 
per Hudson are much more recent than those of the Susque- 
hanna and the Delaware, since glacial streams could not have 
occupied the Mohawk until after the ice-front had retreated 
from northeastern Pennsylvania and the highlands of south- 
ern New York, in which the drainage-basins of the Susque- 
hanna and the Delaware River are situated. When, there- 
fore, the glacial floods of the Mohawk were at their height, 
the Delaware and the Susquehanna had been relieved of 


330 THE ICE AGE IN NORTH AMERICA. 


their excessive burdens, and had subsided to something like 
their present volume, 

As illustrating the capacity of the glacial theory to ex- 
plain the otherwise unaccountable facts connected with the 
recent changes in the drainage of the glaciated region, atten- 
tion is directed to two or three interesting localities east of 
the Alleghanies, where the dry beds of abandoned streams 
have been discovered. | 

We will first consider the outlets of an interesting glacial 
lake which temporarily occupied the upper part of Contocook 
Valley in Hillsborough county, N. H., the details concerning 
which were furnished as early as 1878 by Mr. Upham, in 
the New Hampshire Geological Report. The Contocook 
River now empties into the Merrimack a little above Con- 
cord, and flows in a direction north-northeast. As a conse- 
quence, the present outlet was, toward the close of the Gla- 
cial period, obstructed by ice some time after it had melted 
off from the southeastern portion of the valley. During that 
period a lake was held in the portion of the valley freed 
from ice, at a height sufficient to turn the drainage tempo- 
rarily to the south and southeast. At first the drainage was 
over the water-shed in Rindge, through Ashburnham and 
Winchendon, Mass., and thence into the Connecticut. The 
reality of this line of draimage is evidenced by the exten- 
sive kames and gravel deposits extending from the Conto- 
cook Valley through the towns of Rindge and Winchendon. 
When the ice had withdrawn a little farther north, an outlet 
was open to the southeast into the Souhegan River, and 
thence into the Merrimack. The evidence here is also con- 
clusive that, for a period, a stream of water eighty feet deep 
poured through this pass, and the lake formed in front of 
the ice was in its greatest extent thirty miles long, and from 
two hundred to two hundred and fifty feet in depth. The 
evidence of this remains in delta terraces at that level 
_ formed at various points where streams came into the lake. 

Another instance is in Grafton county, N. H., on the line 
of the Northern Railroad, between Grafton Centre and East 


DRAINAGE OF THE GLACIAL PERIOD. - 331 


Canaan, on the water-parting between the Merrimack and 
the Connecticut, where there is to be found the dry bed of a 
river which for a time flowed through a pass from the Con- 
necticut Valley into the Merrimack, but which is five hun- 
dred feet above the valleys. Here upon this mountain axis, 
in central New Hampshire, nine hundred feet above the sea, 
are numerous and large water-worn circular cavities in the 
rock, technically known as pot-holes, such as are formed in 
shallow rapids, wherever gravel and pebbles become lodged, 
first, in some natural slight depression, and then, through the 
whirling motion given them by the running water, these 
continue to wear a symmetrical depression so long as the 
supply of water continues, or until a channel has been cut 
througb. Pot-holes may be seen in the rapids of almost any 
rocky stream, with the gravel and pebbles, which do the im- 
mediate work when set in motion, still partially filling them. 
Such pot-holes exist in the anomalous position mentioned in 
New Hampshire, where no present stream could by any pos- 
sibility be made to flow. One of them, measured many years 
ago by Jackson, was eleven feet deep, four and a half feet in 
diameter at the top, and two feet at the bottom, and, when 
discovered, was filled with earth and rounded stones.* 

The explanation of this phenomenon furnished by Mr. 
Upham, while engaged on the New Hampshire Survey, is as 
follows: The ice of the Connecticut Valley, being farther 
from the glacial front, lingered considerably longer than that 
in the Merrimack Valley to the southeast, so that for a con- 
siderable period the drainage from the ice-front in the south- 
eastern part of Grafton county was compelled by the ice- 
barrier on the west to flow over this depression into the Mer- 
rimack basin, thus furnishing exactly the conditions neces- 
sary for the production of pot-holes and such other marks of 
water-action as have so long puzzled geologists at this point. 

Similar pot-holes, to be accounted for in like manner, 
have recently been described near Archibald, in Blakely 


* “New Hampshire Geological Report,” vol. iii, pp. 63-66. 


332 THE ICE AGE IN NORTH AMERICA. 


township, Lackawanna county, Pa.* The principal one is 
from fourteen to seventeen feet in diameter at the top, and 
is forty feet deep—the sides being very smooth. The de- 
pression is worn through strata of sandstone, shale, and coal. 
The pebbles which did the wearing were still in the bottom 
of the hole when it was discovered, and are mostly of foreign 
origin, though some of them consisted of pebbles cut from 
the coal-bed itself. The elevation is eleven hundred -and 
twenty-nine feet above tide, and no explanation seems possible 
except that which assumes that a stream of water was kept 
running in that position for a limited period by ice-barriers. 

In passing, it is interesting to remark that the study of 
the glacial deposits in the coal region becomes of great prac- 
tical interest from the relation of their buried channels to 
mining industries. Not only is there money to be saved by 
knowing the depth of the till, and the inequalities of its 
distribution, but the lives of the miners are seriously jeopard- 
ized by ignorance upon this point. On December 18, 1885, 
at Nanticoke, near the vicinity of the pot-hole just de- 
scribed, one of the most shocking mining disasters on record 
occurred, from miscalculating the course of a buried pre- 
glacial channel, which was penetrated by the miners in an 
unexpected place, causing a flood of quicksand, mud, and 
bowlders to fill the mine and immolate twenty-six miners 
beyond hope of rescue. : 

Another instance of glacial drainage worthy of record is . 
reported by Professor J. E. Todd from the Missouri coteau 
in Dakota. Crow Creek flows westward, and enters the Mis- 
souri in Buffalo county, heading well in the terminal mo- 
raine : + 

Two of its principal branches lead us into the heart of 
the great interlobular moraines, the Rees, and the range of 
which Turtle Point is the head, then by unmistakable channels 
trough them to the inner side of the moraine and out upon 


*“ Annual Report of the Pennsylvania Geological Survey,” 1885, pp. 
615--620.. + See map, p. 216. 


DRAINAGE OF THE GLACIAL PERIOD. 333 


the great ice-sheet itself. It produces strange sensations to 
pass up those dry, flat-bottomed valleys, with a steep bank on 
either hand fifty to one hundred and fifty feet in height, 
almost built of bowlders; huge cones of gravel, evidently 
formed in ancient eddies, here and there in the valley ; simi- 
lar valleys joining it now and then. You press on, wondering 
where the beginning can be, for your map tells you that there 
are streams which must cut right across its course if it con- 
tinues as far as you might judge from its width. You press on 
eagerly, you note the banks rapidly subsiding, but the channel 
you tread still preserves its gradual rise, then suddenly you 
come out upon the face of the range, and a magnificent view 
of the plain, two hundred to three hundred feet below, bursts 
upon you. You look for the inclined plane which by easy 
steps has brought you to this altitude, and find it ending 
abruptly with the face of the hills. You realize, as never 
before, the mass of ice which once must have occupied the 
expanse before you. You can see that stream, scores of yards 
in width, leaving its icy banks, now vanished in thin air, for 
the stony ones which still remain.* _ 


It seems clear, also, that the disturbing effects of the great 
ice-sheet upon the drainage of the Northwest will account 
for the numerous deserted river-valleys described by Dr. 
G. M. Dawson in the part of British America lying between 
the Lake of the Woods and the Rocky Mountains. Here 
the conditions were somewhat peculiar. The natural drain- 
age is down the flanks of the Rocky Mountains eastward to 
the Red River Valley. The Saskatchewan River drains the 
northern portion of the territory, while the Assiniboin with 
its branches, the Qu’ Appelle and Souris, drains the southern 
portion—the drainage-basin of the Souris joining that of the 
Missouri in Dakota. The Pembina River, a much smaller 
stream, empties into the Red River near the boundary-line, 
considerably south of the Assiniboin ; and the Sheyenne still 
farther south. 


* “Proceedings of the American Association for the Advancement of Sci- 
ence,” vol. xxxiii, 1884, p. 391. 


334 THE ICE AGE IN NORTH AMERICA, 


With the interpretation which the present discussion has 
put upon the facts, the following is the order of events: Dur- 
ing the farthest extension of the ice to the vicinity of the Rocky 
Mountains, the South Saskatchewan was compelled to flow 
around the front of the ice-sheet to join the Milk River at 
the boundary-line near the one hundred and tenth meridian, 
and thence into the Missouri. A great dry coulée, a portion 
of which is occupied by a large saline lake known as Peeko- 
pee, is a marked feature connecting these streams at the 
present day.* 

Coming eastward to the one hundred and second meridian, 
the Riviere des Lacs seems, without doubt, to have been the 
line of drainage for the Souris River for a distance of sev- 
enty-five or eighty miles. Characteristically enough, this 
ends northward, near the Souris River, “in a broad dry 
coulée, which shallows and dies away in a strip of bowlder- 
covered ground, which stretches northward toward the Souris 
River, five miles distant, and is somewhat lower than the 
general surface of the plain.” 

At this time there was a lake-like expansion of water in 
the Elbow of the Souris, covering Renville, Ward, and Mce- 
Henry counties, Dakota, the evidence of which is still plainly 


seen. This lake, again, was forced to seek a southern outlet, 


which it found through a cowlée in McHenry county into 
the head of the Sheyenne River, and thence followed its 
winding course to Lake Agassiz, near Fargo, where there is 
an immense delta of river gravel. 

Coming still farther east, the Pembina River occupies a 
valley very much larger than its present demands ; and, at. 
its junction with the Red River, there is also an immense 
gravel delta, indicating it as a line of drainage at one time of 
a far larger area than now. Upon following the valley of 
the Pembina up, it is found to continue through the Pelican 
Lake to the Elbow of the Souris, near the one hundredth 


* “Report on the Geology and Resources of the Region in the Vicinity of 
the Forty-ninth Parallel,” pp. 262-268. 


DRAINAGE OF THE GLACIAL PERIOD. 330 


meridian, and twenty-five or thirty miles south of the As- 
siniboin. Professor Hind finds evidence that this was the 
outlet temporarily not only of the Assiniboin but, through 
the Qu’Appelle and the River that Turns, to the South Sas- 
katchewan. Mr. Upham writes me that he has followed this 
old valley for one hundred and twenty-five miles as far as 
Birtle, in Manitoba. According to Professor Hind, the 
length of the valley of the Qu’Appelle, from Birtle up to 
the Saskatchewan, is two hundred and sixty-eight miles in 
direction northwest by southeast. The valley is uniformly 
about one mile wide, and from one hundred and ten to three 
hundred and fifty feet below the general level, and eighty- 
five feet above the present level of the South Saskatchewan, 
the descent being four hundred and forty feet from the 
Saskatchewan to the Assiniboin. The inclosing bluffs con- 
sist mainly of till, and the whole trough is characterized by 
numerous long, shallow lakes. These lines of marginal drain- 
age are readily explained upon the glacial hypothesis here 
maintained, and are a strong proof of that hypothesis. As the 
ice receded, more northern outlets were opened, and these 
temporary channels were naturally abandoned. 


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Fic. 100—Map of South Dakota showing the extent to which the channel of the Missouri 
River was permanently changed during theearly Wisconsinepoch. The brokenlines 
indicate the former course of the Grand, Cheyenne, and White Rivers as they joined 
the original Missouri when flowing through the James River valley. (Map by Todd.) 


336 THE ICE AGE IN NORTH AMERICA, 


According to Professor Todd the preglacial Missouri 
River entered the valley of the James near its upper portion, 
reaching its present channel at Yankton. Having filled this 
valley, the advancing ice from the northeast obstructed the 


mouths of the Grand, Moreau, Cheyenne, and White river . 


and, forcing the drainage in front of the ice across the cols 
between these streams, gave rise to the present tortuous 
channel across the State of South Dakota. Lake Arikaree 
was one of the temporary results of this advance. Its shore 
lines being clearly traced at a height of 400feet above the 


the present Missouri. The bowlders near the Moreau River | 


and the deserted river bed mentioned on pages 146 and 147 
are connected with the existence of this lake. 

Coming still farther southeast, we find that the Minnesota 
River makes a sharp turn to the north at Mankato, and so is 
favorably situated for having its drainage reversed while the 
ice rested over the counties about its junction with the Mis- 
sissippi near St..Paul. The facts are found to be according 
to the programme. There is abundant evidence of a tempo- 
rary lake, covering the territory of Blue Earth and Faribault 
counties, which emptied through a channel known as Union 
Slough, about eight miles long and from one-eighth to one- 
fourth of a mile wide, with bluffs from twenty to thirty feet 
in height, which connect Blue Earth River with the Eastern 
Branch of the Des Moines in Kossuth County, Iowa. 

In this connection it is in place also to refer to the dramatic 
history of Lake Bonneville during the Glacial Period, though 
a fuller account will be necessary in future chapters (see 
pages 615 and 703). This body of water accumulating in the 
basin of Great Salt Lake during the moist and cool climate of 
that period attained a depth of 1,000 feet, covering an area 
of 20,000 square miles. At this elevation there is a distinct 
shore line traceable around the whole distance, broken into 
occasionally by terminal moraines of the glaciers that came 
down from the Wasatch mountains. Near the northeast 
corner of the basin a dirt dam had been formed 375 feet high 


A 
A= oe is —— 


DRAINAGE OF THE GLACIAL PERIOD. 337 


by the wash from the mountains on either side. This dam 
separated the basin from the Port Neuf river which debouches 
upon the Snake river plain at Pocatello. Evidently when the 
opening was once made the whole body of water from the 
upper 375 feet of Lake Bonneville poured down this little 
valley in torrents which baffle all our descriptive powers. 
Evidence of its torrential action are visible all along the 
valley and especially at Pocatello where an immense bowlder 
bed was deposited. (See figures on pages 615 and 703.) 


Nove To THE Fourts Evition.—Since the following chapter upon 
“‘Kames’”’ was written, a partially successful effort has been made to 
distinguish between kames and eskers; but the distinction is not so 
well defined as to make it necessary to rewrite the chapter. Accord- 
ing to Professor Chamberlin (see Geikie’s ‘‘Great Ice Age,”’ third 
edition, p. 746), eskers denote the long gravel ridges which conform in 
general to the direction of the ice movement, while ‘‘kames take on 
the form of bunchy aggregations of knolls and irregular ridges, and 
have a tendency to arrange themselves in belts parallel to the margin 
of the ice.’ But ‘‘it is not to be understood that any sharp line of 
distinction can be drawn between the two types. They are connected 
by intermediate forms which are difficult to place in either class. The 
kames, as well as the eskers, are regarded as products of glacial drain- 


age.” 


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CHAPTER XIV. 
KAMES. 


Tur word “kame” has already been defined as a locai 
term applied to the sharp gravel ridges which abound in 
various parts of Scotland, and which in Ireland are called 
‘“‘eskers,” and in Sweden “osars.” As Mr. Geikie’s work 
on “The Great Ice Age” has given currency to the Scotch 
name, and as the word has been adopted by those who have 
investigated this class of formations most fully in America, 
it seems best to continue its use, though either of the other 
names is more euphonious. This class of ridges was first 
described in this country in 1842 by President Edward 
Hitchcock. Speaking of the gravel deposits in Andover, 
Mass.; known as Indian Ridge, he says they are “a collec- 
tion of tortuous ridges and rounded and even conical hills 
with corresponding depressions between. ‘These depressions 
are not valleys which might have been produced by run- 
ning water, but mere holes, not unfrequently occupied by a 
pond.” * The fuller description of their composition by Mr. 
James Geikie is as good for America as for Europe: 


The sands and gravels have a tendency to shape themselves 
into mounds and winding ridges, which give a hummocky and 
rapidly undulating outline to the ground. Indeed, so charac- 
teristic is this appearance, that by it alone we are often able to 
mark out the boundaries of the deposits with as much precision 
as we could were all the vegetation and soil stripped away and 


* “Transactions of the American Association of Geologists and Naturalists,” 
1842. 


340 THE ICE AGE IN NORTH AMERICA. 


the various subsoils laid bare. Occasionally, ridges may be 
tracked continuously for several miles, running like great arti- 
ficial ramparts across the country. These vary in breadth and 
height, some of the more conspicuous ones being upward of 
four or five hundred feet broad at the base, and sloping upward 
at an angle of twenty-five or even thirty-five degrees, to a height 
of sixty feet and more above the general surface of the ground. 
It is most common, however, to find mounds and ridges con- 
fusedly intermingled, crossing and recrossing each other at all 
angles, so as to inclose deep hollows and pits between. Seen 
from some dominant point, such an assemblage of kames, as 
they are called, looks like a tumbled sea—the ground now 
swelling into long undulations, now rising suddenly into beau- 
tiful peaks and cones, and anon curving up in sharp ridges 
that often wheel suddenly round so as to inclose a lakelet of 
bright clear water.* 


From this description it will be seen that there are some 
remarkable resemblances between kames and terminal mo- 
raines, since both of them are characterized by confused 
hummocks and tortuous ridges of glacial débris, connected 
with numerous bowl-shaped depressions, often containing 


Fig. 102.—Section of kame near Dover, New Hampshire. Length, three hundred feet : height 
forty feet; base, about forty feet above the Cochecho River, or seventy-five feet 
above the sea. a, a, gray clay ; 0, fine sand ; ¢, c, coarse gravel containing pebbles 
from six inches to one foot and a half in diameter ; d, d, fine gravel. (Upham.) 

lakelets. But in other respects there is a marked difference 
between them. In the first place, the material of which 
kames are formed is ordinarily much finer and more water- 
worn, and shows more abundant signs of stratification than 
that of which terminal moraines are composed. Secondly, 
while the terminal moraine forms a ridge at right angles to 
the: motion of the glacier, and marks the limit of its exten- 


* “The Great Ice Age,” pp. 210, 211. 


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KAMES. 41 


sion during a prolonged period, the kames approximately 
coincide in direction with the lines of glacial stria. A large 
part of New England is covered with kame deposits, arranged, 
in general, along the main lines of present drainage, with 
merely such anomalous exceptions as can readily be ex- 
plained by the interference which the ice itself offered to 
the course of the floods which characterized the last stages 
of the Glacial period. » 


NORTH SIDE. 


Fie. 103.—Sections of akameat Bennington Station, New Hampshire. Scale about forty feet 
to the inch. The upper figure shows a simple transverse section ; the lower figure is 
directly transverse on the right side, but longitudinal on the left. Counting from the 
top the strata are : 1, coarse yellow gravel, with pebbles up to eight inches in diame- 
ter, thickness, three to five feet; 2, fine sand, three to five feet; 3, coarse, dark 
gravel, containing pebbles up to one foot in diameter, three feet ;.4, fine sand, ob- 
scured at the bottom by crumbling of the bank, four to eight feet-; a. a. downfall 
of strata with irregular, broken, steep slope, against which lies an accumulation of 
sand ; B, depression of two feet, similar to the foregoing ; Fr, fault, seen only on the 
south side, dislocation of strata, six inches. (Upham.) 

The most satisfactory conclusion with regard to the origin 
of kames is that they mark, in the glaciated region, lines of 
drainage during the closing stages of the Ice age. It is evi- 
dent, from a moment’s reflection, that the streams of water 
resulting from the annual precipitation, combined with that 
from the wasting of the ice during these closing stages, must 
have been enormous, and may very likely have flowed in 
channels quite different from those chosen after the ice had 
completely melted away. Of course, these glacial streams 
must, in the main, have followed the great valleys; but 
many of the minor valleys were, at that time, so obstructed 
that the streams might disregard them and take a more di- 
rect route over the ice through the open channels and long 


tunnels which must then have existed. Those familiar only 


342 ' THE ICE AGE IN NORTH AMERICA. 


with the contracted glaciers of the Alps are scarcely prepared 
to appreciate the extent to which currents of water flow over 
the larger glacial masses and rearrange and transport the su- 
perficial material collected upon them. The “ subglacial” 
streams also are not always strictly subglacial, since they 
often flow through tunnels which are midway between the 
top and the bottom of the ice-mass. In the Muir Glacier, 
Alaska, for example, the two streams issuing from the ice- 
front near the sides of the glacier are several hundred feet 
above the level at which the two streams emerge near the 
center of the channel. There, also, streams of water of more 
or less size can occasionally be seen pouring out from the 
perpendicular front of the ice a hundred or more feet above 
the surface of the inlet. Nor is it any uncommon thing to 
see icebergs move off with water-worn tunnels in them 
which are still well filled with gravel and pebbles. In the 
various depressions in the surface of the glacier also, where 
at times extensive lakes of water are formed, there is much 
accumulation and assortment of earthy material far back from 
the terminal margin of the glacier. 

We will now endeavor briefly to reproduce the conditions — 
in New England near the close of the Ice age, in order to 
see how the facts fit into the theory just enunciated. 

The main north-and-south valleys of New England are 
now drained by the St. John, the St. Croix, the Penobscot, the 
Kennebec, the Androscoggin, the Merrimack, and the Con- 
necticut Rivers, with various smaller subordinate drainage- 
basins, such as the Machias, the Saco, and the Piscataqua. 
The larger valleys are also joined by various subordinate 
ones, tributary to them, running in various directions con- 
formable to the general contour of the country. But the 
present course of the rivers is not necessarily determined 
at every point by barriers of any great height. For exam- 
ple, there are no high barriers separating the northeastern 
portion of the Penobscot drainage-basin from the sources of 
the St. Croix and Machias Rivers. South of the Rangeley 
Lakes, also, where Ellis River joins the Androscoggin, it is 


KAMES. 343 


only a barrier of two or three hundred feet which causes the 
present deflection of the river to the east, through Lewiston 
to Brunswick. The great bend made by the Merrimack 
River at Lowell, Mass., is also caused by a glacial deposit to 
the south of only fifty or sixty feet in height. 

It is easy to see that. during the period of most rapid 
retreat, when the waters of the wasting ice-sheet over New 
England were seeking their ultimate channels, the lower 
portion of the ice itself was an important element in deter- 
mining the minor deflections in these lines of drainage. An 
ice-barrier of a few hundred feet in the Penobscot, between 
Passadumkeag and Mattawamkeag, would force the drainage 
of the Aroostook region into the valley of the Machias, and, 
in the predominance of the mountains from which the west- 
ern branches of the Penobscot River descend, we have a 
cause favoring such an extension of the ice as would produce 
the results indicated. In the case of the Merrimack River, 
the fact that, from Lowell to Newburyport, it flows in a 
northerly direction would also furnish a probable ice-barrier 
which for a time would drive the drainage of this basin di- 
rectly southward from Lowell and Lawrence toward Boston. 

It is not necessary to go into all the details concerning 
the intricate network of kames which mark the lines of 
drainage over New England, when ice-barriers to so great 
an extent directed the flow of the glacial torrents. The facts 
are impressive. Individual kames can be traced for long dis- 
tances, sometimes a hundred miles or more. The main lines 
in New England are shown on the accompanying map, be- 
ginning on the eastern side of Maine.* 

A few points merit particular attention. The Connecti- 
cut River Valley, from its sources to the Massachusetts line, 
contains the remnants of what seems to be a pretty continu- 
ous kame, but which has been largely eroded, and in many 
cases covered up by subsequent deposits of river-silt. Almost 


* See also “Kames and Moraines of New England” in “ Proceedings of the 
Boston Society of Natural History,” vol. xx, p. 211 ef seg. 


344 THE ICE AGE IN NORTH AMERICA. 


everywhere we find illustrations in the partial burying of 
kames by such river-silt that the deposition was previous 


S Chamberlain 
L. 


Y 


Gy St. Francis 


L.. Megantie 


ie 


SCALE OF MILES 
20 40 60 


wicuthers ¢ Co., Engr’s, N.Y. 


Fic. 104.—The kames of Maine and southeastern New Hampshire. The extension from 
New Hampshire can be seen in Fia. 101. (Stone.) 


to and independent of the present streams. For example, 
the Merrimack, between Lowell and its mouth, is crossed at 
right angles by two or three lines of kames, which descend 
into the valley from one side and come out upon the hills on 
the other. While crossing the valley these are partially, 


KANES, 345 


and in some places completely, buried beneath the river-silt 
which forms the present flood-plain. In one case, a few 
miles below Lowell, the end of this ridge, completely cov- 
ered with river-silt, may be seen where the river has cut 
across the old barrier. Professor Charles Hitchcock gives 
a similar section of a buried kame in Hanover, N. H., though 


wef aE Hanover Ag. Coll, Delta of 
w Terrace of Bloody Br., js Sas ~ Bw common, farm, ‘Mink. Br, 
= Norwich village, 525. ox <4 % m Ma 545. 500. 564. 


350 ft, 

above 

Seva. 

Fig. 105.—Section across the Connecticut Valley, from Norwich, Vermont, to Hanover, New 
Hampshire, distance three miles. The kame is nearly covered by later river silt. 
(Upham. ) 


~~ aee  Oe ee e e  ee  oe 


in this case it is parallel with the river, and not, as in the 
other, at right angles to it.* 

Inasmuch as the interpretation of the facts in the valley 
of the Connecticut is open to some question, and as the de- 
cision with respect to them will have an important bearing 
on our whole conception of the closing scenes of the Glacial 
period, it will be worth while to consider them more fully. 

Mr. Upham, in his survey of the Connecticut Valley,t 
discovered what he considered to be a line of kames extend- 
ing throughout nearly the whole length of the valley, though 
it had been much eroded in places, and in others was partially 
or completely buried by river-silt ; but of the character of the 
deposit as a true kame he felt quite confident —that is, he con- 
sidered that the line of gravel ridges which he found winding 
from side to side down this valley were deposited as the ice 
retreated, after the manner we have described in channels 
and tunnels formed near the front. In this view these ridges 
in age are intermediate between the till and the regular river 


* “Proceedings of the American Association for the Advancement of Sci- 
ence,” vol. xxxi, p. 8328; also Upham, in “ Geology of New Hampshire,” vol. iii. 

+ See “Geology of New Hampshire,” vol. iii, pp. 3-177; also, “ American 
Journal of Science,” vol. cxiv, 1877, p. 459. 


346 THE ICE AGE IN NORTH AMERICA. 


terraces—being newer than the till and older than the ter- 
races. 

On going over the ground in 1881 with Mr. Upham’s 
notes in his hands, Professor Dana concluded that what Mr. 
Upham had called kames were in reality a portion of the 
regular terrace formation. In Professor Dana’s view, the 
reputed kames are merely the coarser part of the terrace 
material accumulated in excessive amount in the larger val- 
ley wherever tributary streams brought into it their heavier 
burdens from the higher land. On this theory, the height 
of the floods in numerous localities must have been between 
two hundred and three hundred feet above low water in the 
river ; for in various places these deposits are at that height 
above the river. But upon the supposition that they are 


Segregated veins 
anJower portion. 


375 ft. above sea. wenn orn HFT 


Fia. 106.—Section east from Ledyard Bridge, Hanover, New Hampshire, showing segre- 

ame above the river, one hundred and forty fect. (Upham.) 
kames, deposited when the ice itself formed barriers to keep 
the streams in various abnormal positions, the glacial floods 
would not need to be more than from one hundred to one 
hundred and fifty feet in height, since that is all that is 
required for the deposition of the highest river-silt which 
occurs. 

It must be confessed that Professor Dana’s estimates of 
the size of the Connecticut River floods at that time are 
somewhat startling, even with all the changes of level for 
which he provides in his theory.* For, after reducing, by 
reason of the Champlain depression, the gradient of the 
stream during the close of the Ice period by one third, the 


* “ American Journal of Science,” vol. cxxiii, 1882, p. 198. 


KAMES., | 347 


slope of the surface of the Connecticut would still have been 
more than one foot per mile. This, in a torrent 2,500 feet 
wide, with a depth of 140 feet, would produce a current of 
eight miles per hour on the surface and of six miles on the 
bottom. With this size of the flood, the rate of discharge 
would be about four hundred cubic miles of water per an- 
num; whereas, at the present time, the total discharge of a 
year is only about five cubic miles. To cause this enormous 
rate, Professor Dana supposes that, for a short period, the 
Connecticut glacier melted at the rate of more than a cubic 
mile per day. As he estimates the area of this drainage-basin 
to be about 8,500 square miles, this would imply that at times 
as much as eight inches per day melted from this surface. 
This rapid rate of removal in summer is not, however, sup- 
posed to continue for a long period—probably less than five 
years. Professor Dana supposes that, at that time, the long 
tunnels worn in the glacier by the Connecticut and its tribu- 
taries, when they existed as subglacial streams, had become 
open channels in the ice. | 

Later and fuller investigations of Professor Emerson, 
give a different interpretation to many of the facts in the 
Connecticut Valley. It would now appear that the ice dis- 
appeared from the high lands on either side before it did in 
the valley, so that there was aseries of marginal lakes at 
successively lower levels leaving accumulations of gravel, 
and these were traversed occasionally by kame-like ridges. 
This conforms to what was evidently the course of events in 
the Champlain Valley parallel to it. There high-level gravel 
deposits which were at first supposed to be indications of a 
general depression of land, are explainable on the theory of 
marginal glacial lakes. 

The shore lines of such marginal lakes are clearly marked 
at Bakersfield, Franklin County, Vermont, and southward 
in the valleys of the Lamoile and Winooski rivers. The 
bowlder channel in Chazy, N. Y., described above, p. 320, 
marks as already said a water weir between the decaying 
ice-sheet and the Adirondack Mountains. 


348 | THE ICE AGH IN NORTH AMERICA. 


The levelly stratified plains of sand and gravel which 
spread out around the southern end of the kame systems, and 
which to a greater or less extent border their margin through- 
out their entire length, should not be passed without notice, 


Fia. 107.—Buried kame near Stroudsburg, Pennsylvania. (Lewis and Wright.) 


since they in a remarkable degree confirm our general theory 
concerning the origin of kames. As has been said, the 
kames mark the great lines of drainage which poured over 
the southern margin of the glaciated area during its later 
stagos when the ice itself furnished numerous and important 
barriers to direct the torrents, and when the earthy material 
in and on the ice was readily at hand to be’swept along by 
these temporary streams. The pebbles, sand, and gravel 
lodged by the way in the ice-channels, and on the surface, 
furnished the material from which the kames were to be 
formed. Wherever these streams came out of their confine- 
ment and flowed over a level country, they deposited vast 
deltas of sand and gravel, analogous to those that are now 
being deposited at the mouths of all large rivers. One of the 
most remarkable of these kame-deltas is that in Cherryfield 
and Deblois, near the eastern coast of Maine. This sandy 
plain, many miles in extent, is not an ocean deposit, but can 
be readily connected with the streams which deposited to the 
north of it one of the largest belt of kames in the State, and 
whose course can be traced for nearly one hundred miles 
toward Mount Katahdin. Down the line of the kame there 
poured, between icy walls, during the closing stages of the 
Glacial period, a vast but fitful silt-laden stream of water, 
which, as it emerged from its more constrained limits within 
the ice-sheet, was slackened in its movement and rapidly de- 


KAMES. 349 


posited the strata of sand and gravel forming the above- 
mentioned delta-plain.* 

This is but a type of innumerable other places. As the 
ice receded and the mouth of the kame-streams retreated to 
the north, the line of these deposits receded, and deltas were 
pushed out now upon one side and now upon another of the 
central kame. Often one can see these aprons of stratified 
deposits stretching out from the base of the kame into a 
swamp, the stream at that point not having been stationary 
Jong enough to allow the whole depression into which it was 
flowing to become filled with silt. Nearly all of the exten- 
sive gravel deposits in New England are thus related to some 
kame system, so that, when once their origin became under- 
stood, they were the means of assisting in the discovery of 
the kames themselves. An interesting illustration of this 
occurred in the case of the kames running through the 
Rangeley Lakes from north to south, and extending to the 
Androsceggin River and beyond, south of Andover, Me. 
From the extent of the gravel plains to the north of Port- 
Jand, Mr. Upham had surmised that a kame-stream must 
have come down from the north to account for the deposit. 
My brother, Rev. W. E. C. Wright, was soon after requested 
to look for such a kame in the course of a pleasure-trip he 
was about to make to these lakes. This he did, and the re- 
sult was that, what Mr. Upham had seen with the mind’s 
eye, the summer tourist had no difficulty in finding in reality. 
The kame can be traced up the stream not only to the lakes, 
but through and across them—their backs appearing occa- 
sionally above the water, and their line forming a shoal from 
one side to the other 

These aprons of over-wash gravel, marking the deltas of 
the kame-streams during the close of the Ice age, also char- 
acterize the whole glacial border to a greater or less extent. 
The entire south side of Cape Cod and of Long Island + pre- 


* See map, p. 344. 
+ See “The Geologica! Formation of Long Island, New York, with a Descrip- 
tion of ite “ld Water-Courses,” by John Bryson, 1885. 


300 THE ICE AGE IN NORTH AMERICA. 


sents a bordering plain of sand and gravel, deposited, in the 
manner above described, about the base of the great terminal 
moraine, and decreasing in height as the distance increases 
from the base to the south. Similar deposits characterize 
the southern flanks of the kettle-moraine of Wisconsin and 
its extensions both east and west. Several such are crossed 
upon the railroad from Elkhorn to Eagle, in Walworth county, 
Wis., where the hills of the moraines are to the north, and 
much low, swampy land lies to the south and east. It is evi- 
dent that the ice remained here just long enough for the cur- 
rents of water which swept down from the moraine to fill the 
depression with sand and gravel from its base down to the 
line of the railroad, whereupon the retreat of the ice-front 
allowed the course of the drainage to change, and to build 
up deltas at some other point. : 

The discussion of kames is not complete without directing 
attention to the fact that they do not by any means always 
occupy a continuous slope from the highlands to the glacial 
margin; and this has an important bearing upon the ques- 
tion of the mode of their formation, and their connection 
with ice-barriers and with ice-channels. Frequently, when 
following a kame down a gentle incline or over a level plain, 
it will be found that, on coming to a transverse valley one 
hundred and fifty or two hundred feet in depth, and perhaps 
more, the kame is not interrupted, but it descends into the 
valley on one side, and ascends on the other to the level plain 
beyond. This feature of the kames across the Merrimack 
River above Lawrence, Mass., has already been referred to. 
and it early attracted my attention, and was fully described 
in one of my first papers on the subject.* | 

Another interesting illustration of this phenomenon, and 
one which reveals the ingenuity of the investigator, is re- 
lated by Professor Stone respecting the kame which crosses 
Schoodic Lake in eastern Maine. He had followed the kame 


* See ““Some Remarkable Gravel Ridges”; also, ‘‘The Kames and Moraines 
of New England”; also, map p. 338. ‘ 


KAMES. 301 


to the north end of the lake, and had also learned of its ex- 
istence on the south end. Wishing to ascertain whether the 
kame was continuous to the other end, he inquired of the 
Jumbermen who are in the habit of “ warping” rafts of logs 
through the lake whether there was not a line of shoal water 
through it. But none of them had become aware of any such 
shallow line.* On asking them, however, if the anchorage 
was equally good at all places in the lake, they at once re- 
plied that it was not; that at certain places the bottom was 
gravelly, and the anchors would not hold. Upon asking what 
they did in such an event, they replied that all they had to 
do was to take the anchor to one side or the other, when usu- 
ally there was no difficulty in finding a good bottom. The 
explanation, to Professor Stone’s mind, of this state of things 
was, that the gravelly places of poor anchorage were along 
the line of the kame, and, by asking the lumbermen to mark 
upon the map the places where the anchor was in the habit 
of dragging, and which they were compelled to avoid, he 
was able to trace the kame from one end of the lake to the 
other. | 

Instances like this, of the indifference of the kames to 
the minor irregularities of the slopes of the valleys in which 
they are situated, are frequent. One worthy of special note 
is found in the valley extending from Wakefield, Carroll 
county, N. H., northward to Ossipee Lake. In this case 
two kame systems meet each other in the depression of the 
lake, having slowly descended for many miles, the one from 
the north and the other from the south. The explanation 
is that the outlet of Ossipee Lake is to the east, joining the 
Saco River at Cornish. Evidently this drainage-channel 
through the ice was opened while the ice still filled the 
southern part of Carroll county as far south as the head- 


* The process of warping rafts is as follows: An anchor is taken out some 
distance ahead of the raft and dropped upon the bottom; whereupon a wind- 
lass upon the raft connected with a rope that is fastened to the anchor is turned, 
and the raft is thus slowly drawn to the point over which the anchor is caught, 
when the anchor is raised and again taken forward, to have the process repeated. 


doz THE ICE AGE IN NORTH AMERICA. 


waters of the Piscataqua River. Thus there was, along a 
certain margin of the ice, a backward drainage of twenty 
miles or more, which offers a ready explanation for this 
seeming anomaly in the relation of the kame to the general 
slope of the valley down which the ice had moved. 

Several other instances, equally marked, described by 
Professor Lewis,* exist in the eastern counties of Pennsyl- 
vania. In these cases a great amount of glacial débris had 
been deposited upon the ice, a little back from its front, on 
the west side of the Delaware River, both above and below 
the Water-Gap. South of the Water-Gap these deposits are 
several hundred feet higher than the Delaware River, and 
lie between it and Kittatinny Mountain. When the Dela- 
ware had opened its own channel back to the present site of 
Portland, just below the Water-Gap, a line of backward 
drainage was established from the higher land on the south- 
west toward the northeast. This line is now marked for a 
number of miles by a very well-developed system of kames. 

A similar line of kames descends the valley of Jacobus 
Creek along the line of drainage to the Delaware River, 
sloping backward from the glacial margin near Johnson- 
ville toward Stroudsburg. Down this backward slope, for 
a distance of five miles or more, the kames are very con- 
spicuous. 

The gravel-ridges occurring in the southern or upper end 
of the numerous transverse valleys containing the Finger 
Lakes of central New York seem to be similar instances of 
kames formed by backward drainage. The course of events 
there seems to have been as follows: After the ice melted 
back to the water-shed between the Mohawk and the Sus- 
quehanna River, a large amount of water-worn material 
accumulated upon and about the margin before the great 
line of drainage through the Hudson and Mohawk Rivers 
opened. When, finally, the streams of this region were re- 


* “Marginal Kames,” in “ Proceedings of the Society of Natural Sciences,” 
Philadelphia, June 2, 1885, pp. 157-173. 


KAMES. 008 


stored to their natural course, and the drainage-line of the 
Mohawk was resumed, these kames of the Finger Lake re- 
gion would be naturally formed. 

Westward from New York the conditions are not favor- 
able for the formation of this class of glacial deposits. Still, 
there are numerous short series of kames in Ohio at the low 
place in the water-shed between the lake and the tributaries 
to the Ohio River. Through these the glacial torrents poured 
over into the southern streams during all that period when 
the outlet through the Wabash was closed up and the dam 
across the Mohawk Valley was at its height. Kames are 
abundant in Summit county, between Ravenna and Akron, 
and southward, and in the neighborhood of Seville, im Me- 
dina county. 

Occasional kame-like ridges are reported farther west, as 
in Pipestone county, Minn.* But, according to the testi- 
mony of Mr. Upham, whose experience is wider than that 
of any one else in these investigations, “ prolonged kames, 
comparable with those of Sweden and Scotland, and with 
those described in Maine, New Hampshire, and Massachu- 
setts, have not been found.” + 


A summary of the last three chapters may be helpful here: 
_ The extreme length of preglacial as compared with post- 
glacial time is evident from the enormous extent of pregla- 
cial erosion. Outside the glaciated region all the rivers oc- 
cupy deeply eroded valleys, showing the great length of the 
time through which eroding agencies have been at work. 
The post-glacial gorge of Niagara is but seven miles long, 
whereas the preglacial gorge of Ohio is both wider and 
deeper than that, and is more than a thousand miles in 
length. 

It is easy to see that all the northerly-flowing streams of 
preglacial drainage would be dammed up by ice during the 


* “Geological and Natural History Survey of Minnesota,” vol. i of the final 
report, p. 545. 
+ Ibid., “ Ninth Annual Report,” p. 290. 


304 THE ICH AGE IN NORTH AMERICA. 


greater part of the Glacial period. Of this as a reality there 
is abundant evidence. All the streams which rise within 
the glaciated region and flow southward were ecmpelled to 
carry away not only the annual precipitation, but, during 
the closing stages of the period, the waters of the accumu- 
lated precipitation of many thousands of years. If. the an- 
nual spring freshets of these streams are oftentimes terrific, 
what must have been the spring freshets in the Glacial period 
itself ! 

Into the Mississippi also were poured the surplus waters 
which now flow down the St. Lawrence, and into Hudson 
Bay. Lake Erie emptied its waters through the Wabash 
River, and Lake Michigan down the Illinois; while the 
great region drained by the Red and other rivers of Mani- 
toba and British Columbia had their outlet through Lake 
Traverse and Big Stone Lake, into the Minnesota, and 
thence into the lower Mississippi. The terraces of the gla- 
ciated region are the direct results of these glacial floods, 
and can be studied on every stream within its boundary. 

Besides the glacial terraces of our present streams, we 
have, in the so-called “kame systems,” still further evidence 
of the existence of temporary lines of drainage determined 
by ice-barriers. New England is gridironed by a system of 
gravel-ridges deposited by glacial streams which were, to a 
great extent, independent of the minor features in the pres- 
ent topography. In these and in the terminal moraines we 
study the skeleton of the continental ice-sheet as intelli- 
gently as the anatomist can study the skeleton of a dis 
sected animal. 


i eee 


CHAPTER XV. 
GLACIAL DAMS, LAKES, AND WATERFALLS. 


No single cause has done more to diversify the surface of 
the country, to add to the attractiveness of the scenery, and 
to furnish the key by which the conditions of the Ice age 
can be reproduced to the mind’s eye, than glacial dams. To 
them we owe the present existence of nearly all the water- 
falls in North America, as well as nearly all the lakes, while 
the shore-lines and other marks of temporary bodies of water 
produced by ice-barriers are of the most instructive character. 

In the chapter upon “Glacial Erosion and Transportation” 
we have already spoken at some length of rock-basins which 
have been formed by glacial action. In the case of the so- 
called cirgues there described, there can be no question that 
they have been produced by ice-action, the rocks being worn 
deepest where the ice impinged upon them most directly and 
for the longest period of time, leaving at the front a rocky 
rim much higher than the bottom of the czrgue. To what 
extent the fiords, and the lakes which are some distance from 
mountain declivities and have rock-rimmed basins, owe their 
origin to the same cause, is an unsettled question ; and still 
greater doubt appertains to such basins as are occupied by 
the great lakes of the United States and British America, 
Professor Newberry, whose opportunities for investigation 
have been most ample, would attribute these lake-basins 
largely to glacial erosion.* 


* “ Notes on the Surface Geology of the Basin of the Great Lakes,” “ Bos- 
ton Society of Natural History. 1862”; “Geological Survey of Ohio, Report of 


306 THE ICE AGE IN NORTH AMERICA, 


It is fair to Professor Newberry, however, to state that 
he never took extreme grounds upon this point, but that his 
fullest statement of the theory, written for the second vol- 
ume of his “ Report of the Geological Survey of Ohio,” was 
well matured, and gave weight to all the agencies which 
combined with ice-action to produce these basins. The facts 
which have to be borne in mind with reference to the Great 
Lakes are briefly these: 1. Lakes Ontario, Erie, Huron, and 
Michigan, being surrounded by sedimentary rocks whose 
strata at the present time lie nearly horizontal, evidently 
occupy valleys of erosion. The western end of Lake Supe- 
rior, however, occupies a synclinal trough, and is doubtless 
partly due to an early warping of the earth’s crust. 2. The 
bottoms of all these lakes, except Erie, are lower than the 
present sea-level, the depression in the case of Superior 
being 375 feet ; Michigan, 286; Huron, 127; Ontario, 507. 
If, then, these lakes occupy valleys of erosion, it is an inter- 
esting question to determine how any erosive agency could 
have operated to such a depth below sea-level. 

Professor Newberry’s theory is that, previous to the Gla- 
cial period, the region to the south and southwest of Hudson 
Bay was considerably elevated above its present position, 
and that from early ages the lines of drainage had been 
established in pretty much the same general course as at 
present, forming valleys of considerable extent where now 
the lake-basins exist; that, when the Ice age came on, the 
country to the north was still at a higher elevation than 
now, and as the local glaciers increased, they occupied, en- 
larged, and in some cases deepened, these old river-valleys, 
both by direct action in eroding the rocky basin and by 
the deposition of great quantities of glacial detritus. But 
his own statement of the theory is so perspicuous and 


Progress for 1869”; “The Surface Geology of the Basin of the Great Lakes 
and the Valley of the Mississippi,” “‘ Lyceum of Natural History Society, New 
York, 1869”; “The Surface Geology of Ohio,” “Report of Geological Survey 
of Ohio,” vol. ii, 1874 ; “‘ The Geological History of New York Island and Har- 
bor,” “‘ Popular Science Monthiy,” 1878. 


GLACIAL DAMS, LAKES, AND WATERFALLS. 357 


condensed that we can do no better than reproduce the most 
of it: 


Previous to the Glacial period the elevation of this por- 
tion of the continent was considerably greater than now, and 
it was drained by a river system which flowed at a much lower - 
level than at present. At that time our chain of lakes— 
Ontario, Erie, and Huron—apparently formed portions of: the 
valley of a river which subsequently became the St. Lawrence, 
but which then flowed between the Adirondacks and Appa- 
lachians, in the line of the deeply buried channel of the Mo- 
hawk, passing through the trough of the Hudson and empty- 
ing into the ocean, eighty miles southeast of New York. Lake 
Michigan was apparently then a part of a river-course which 
drained Lake Superior and emptied into the Mississippi, the » 
Straits of Mackinaw being not yet opened. 

With the approach of the cold period, local glaciers formed 
on the Laurentian Mountains, and, as they increased in size, 
gradually crept down on to and began to excavate the plateau 
which bordered them on the west and south. ‘The excavation | 
of our lake-basins was begun, and perhaps in large part effect- 
ed, in this epoch. 

As the cold increased and reached its maximum A ete a 
great ice-sheet was formed by the enormously increased and 
partially coalescing local glaciers of the former epoch. This 
many-lobed ice-sheet, or compound glacier, moved radiatingly 
from the south, southwest, and western slopes of the Canadian 
highlands, its Ohio lobe reaching as far south as Cincinnati. 
The effect of this glacier upon Lake Erie and Lake Ontario 
would be to broaden their basins by impinging against and 
grinding away with inconceivable power their southern mar- 
gins. ‘To the action of this agent we must ascribe the peculiar 
outline of the profile sections drawn from the Laurentian 
Hills across the basin of Lake Ontario to the Alleghanies, and 
across that of Lake Erie to the highlands of Ohio, viz., a long, 
gradual slope from the north to the bottom of the depression, 
and then an abrupt ascent over the massive and immovable 
obstacle against which the ice was banked, until, by the ws a 
tergo, it overtopped the barrier. In New York that barrier 


308 THE ICE AGE IN NORTH AMERICA. 


was a shoulder of the Alleghanies, too high and too rugged to 
be buried under a continuous ice-sheet; but its whole front 
was worn away for a hundred miles or more, and it was deeply 
creased where now we see the peculiarly elongated lakes of 
New York, and cut through in certain gaps, to the valley of 
the Delaware. In Ohio the erosion was easier and carried far- 
ther south. The barrier was also lower, and was finally over- 
topped by one great lobe of ice, which flowed on to the south 
and west until its edge reached the Ohio River... . 

With the amelioration of the climate the wide-spread ice- 
sheets of the period of intensest cold became again local gla- 
ciers, which completed the already begun work of cutting out 
the lake-basins. At first, the glacier which had before flowed 
over the water-shed in Ohio was so far reduced as to be unable 
to overtop its summit; but, deflected by it, it flowed along its 
base, spending its energies in cutting the shallow basin in 
which Lake Erie now lies. 

A further elevation of temperature curtailed the glacier 
still more, and Lake Erie became a water-basin, while local 
glaciers left from the ice-sheet excavated the basins of Lake 
Michigan, Lake Huron, and Lake Ontario. The latter lake 
was apparently formed by the same glacier that made the Erie 
basin, but when much abbreviated. It flowed from the Lau- 
rentian Hills and the north slope of the Adirondacks, and was 
deflected by the highlands south of the lake-basin, so that its 
motion was nearly westward. This chapter in the history of 
our lakes was apparently a long one, for Lake Superior, Lake 
Michigan, Lake Huron, and Lake Ontario are all of great 
depth. 

The melting of the glaciers was accompanied, perhaps 
occasioned, by a sinking of the continent, which progressed 
until the waters of the Atlantic flowed up the valley of the St. 
Lawrence to Kingston, and up the Ottawa to Arnprior (Daw- 
son). The valleys of the St. Lawrence and the Hudson were 
connected by way of Lake Champlain, and thus the highlands 
of New England were left as an island. It is also possible that 
the sea-water penetrated to the lake-basin through the valley 
of the Mohawk and through that of the Mississippi, but of 
this we have no evidence in the presence of marine fossils in 


GLACIAL DAMS, LAKES, AND WATERFALLS. 359 


the surface deposits. The great area of excavation in which 
the lakes lie was probably at this time filled to the brim with 
ice-cold fresh water; and this, flowing outward through all 
the channels open to it, may have been sufficient to prevent 
the entrance of the arctic marine mollusks, of which the re- 
mains are so abundant in the Champlain clays of the St. Law- 
rence Valley and the Champlain basin.* 


Lakes caused by glacial dams are of two classes: 1. Those 
produced by the irregular deposition of moraine material ; 
2. Those caused by the ice itself during the period of its 
continuance. The first of these classes may also be profit- 
ably subdivided into—(1) Those caused by deposits which 
have closed up old water-courses ; (2) Those caused by de- 
posits producing complete inclosures of the nature of kettle 
holes. 

Making the last class the first subject of consideration, 
we note that by far the larger number of the small lakes 
which diversify the glaciated region occupy the basins of 
kettle-holes. When treating of terminal moraines and 
kames, kettle-holes were spoken of as one of the prominent 
features characterizing these deposits, and the origin of the 
smaller ones at least was said to be due to the melting away 
of masses of ice which had from time to time been covered 
by the earthy débris which accumulates near the front and 
along all the great lines of drainage of extensive glaciers. 
Protected for a while by this débris from melting, these 
masses of ice first begin to disappear around the exposed 
edges of their sides, allowing the sand, gravel, and pebbles 
to be heaped up about their bases, so that, upon the final 
disappearance of the ice, an inclosure is left, varying in size, 
shape, and depth according to the extent of the ice-mass 
inclosed. Many of these kettle-holes are dry throughout the 
larger part of the year, since they are above the general 
level ; and the surrounding material of the rim is so coarse, 
that, even after long-continued rains, the water remains in 


* “ Geology of Ohio,” vol. ii, pp. 77-79. 


360 THE ICH AGE IN NORTH AMERICA. 


them but a short time; while others, whose bottom is below 
the general surrounding water-level, or whose rims chance 
to be of more compact material, retain a small amount of 
water during the most of the season, or throughout the 
entire year. In innumerable cases peat has accumulated in 
the bottom of these, and filled up a considerable portion of 


the lower part of the cone-shaped depression. It is thus that — 


nearly all the peat-bogs of New England and the Northwest 
have originated. In numerous cases the peat forms a rim 
about the edge at the water-level, while in the deeper por- 
tion the surface of the clear water looks up from the shad- 
ows, or reflects the sunshine like the pupil of a gigantic eye. 
In respect. to these glacial lakes partially surrounded by 
accumulations of peat, one almost uniformly finds local tra- 
ditions that they are without bottom, or at least that no one 
has been able to find it. The fact is, however, that they are 
none of them of great depth ; but the soft ooze of muck and 
mud which accumulates at the bottom renders sounding 
impracticable, and thus originates the illusion of unfathom- 
able depths. , 

The lakes and bogs of Ireland present familiar examples 
of this class of glacial inclosures ; while in this country one 
can not easily run amiss of them, either in New England or 
the Northwest. The southeastern portion of Massachusetts 
abounds in them in special degree. As before remarked, 
Plymouth county is little less than a ganglion of such gla- 
cial lakes with their inclosing deposits—Plymouth township 
alone being reputed to have three hundred and sixty. They 
appear all along the line of the terminal moraine, often cap- 
ping its very summit in the western portion of Long Island, 
even within the limits of the city of Brooklyn. 

As shown in a previous chapter,* the Elizabeth Islands 
consist of a network of deposits surrounding such depres- 
sions ; but in this case, as frequently elsewhere, the rims are 
of such coarse material that most of the depressions are dry. 


* See p. 205. 


GLACIAL DAMS, LAKES, AND WATERFALLS. 361 


All the lines of the kame-deposits in Maine, New Hamp- 
shire, and Massachusetts are marked by the frequent occur- 
rence of lakes and dry depressions of this description. 
“Tight Pond,” the name of one in the vicinity of Conway, 
N. H., is suggestive of its character. The resemblance so 
often noted by tourists between the scenery of Michigan 
and that of large portions of Ireland is produced by the pre- 
ponderance in both regions of this class of lakelets. The 
innumerable lakes of Wisconsin and Minnesota had a similar 
origin, and are limited chiefly to the tortuous line of the 
great Kettle Moraine, heretofore described as being so 
marked a feature in the topography of the country between 
Lake Michigan and Dakota. 
It was a long time before the true origin of these lake- 
lets in the Northwest was suspected. But no sooner was 
Mr. Upham set to survey the field in Minnesota, than, with 
his knowledge of the glacial phenomena of New England, 
he detected their character, and at once adopted a provisional 
hypothesis by which he successfully and economically direct- 
ed his future glacial investigations in the State. The lake- 
lets and dry depressions above Minneapolis, including even 
Lake Minnetonka itself, he perceived to be kettle-holes, such 
as characterize the terminal moraine on the southern shore 
of New England, and at once inferred that the moraine in 
that State would be found running along the curved lines 
formed by these lakelets, as laid down upon the maps by the 
topographical surveyors. There was a belt of such lakelets 
running a little west of north from Minneapolis, between 
the valley of the upper Mississippi and that occupied by the 
Minnesota and the southern part of the Red River of the 
North. In the vicinity of Minneapolis there was also a 
peculiar enlargement of this area of lakelets, whence it ex- 
tended into northern Iowa, but, for a width of sixty or 
seventy miles, and a length of two hundred and fifty or 
three hundred miles up and down the Minnesota Valley, 
there was a striking absence of lakes upon the maps. They 
reappeared again, however, to the west, in a line nearly par- 


362 THE ICE AGE IN NORTH AMERICA. 


allel with the first one described, and extended through the 
Coteau des Prairies of eastern Dakota. A single season’s 
work was sufficient amply to verify Mr. Upham’s hypothe- — 
sis, and all subsequent investigation has confirmed it, prov- 
ing that there was an independent movement of ice down 
the Minnesota Valley, pushing its lobate front far into the 
State of Iowa, and some distance beyond the part reached 
at that time by the general mass on either side. About 
this lobate margin a vast moraine was built up, whose 
irregular deposits formed the inclosures containing the lake- 
lets of that region. Over the intervening area, for a width 
of seventy miles, there is little left but the ground mo- 
raine, which is uniform in character, and from which the 
ice melted so rapidly that there was no chance for the for- 
mation of lakelets such as characterized the margin where 
the ice-front remained during the larger part of the 
period. 

Another class of glacial lakes is due to dams of glacial 
débris such as were spoken of in a preceding chapter. The 
lakes of this class are not so numerous as the former, but pre- | 
sent a greater variety of problems for investigation. To 
appreciate this part of the glacier’s work, we must bring 
again to mind the extent to which erosion had proceeded 
before the Glacial period began. As already detailed, the 
vast extent of preglacial erosion is apparent at once upon 
entering the unglaciated region upon the western flanks of 
the Alleghany Mountains, where all the rivers occupy nar- 
row troughs of erosion, hundreds of feet deep, and extending 
to the very sources of the streams. There are, over that un- 
glaciated region, few if any waterfalls, simply because the 
recession of the cataracts which once existed has in most 
cases proceeded so far that the streams have completed their 
work, and have already cut their channels through to their 
extreme limit. The State of Ohio is a portion of the Appa- 
lachian uplift, and its surface, for the most part, is more than 
a thousand feet above the sea. The southeastern part of 
the State is unglaciated, and is characterized by the freedom 


GLACIAL DAMS, LAKES, AND WATERFALLS. 363 


from waterfalls, and that depth and extent of the eroded 
valleys, which would naturally result from the prolonged 
continuance of water-action. On the contrary, the glaciated 
portion of the State presents a surface in the main remark- 
ably free from the effects of prolonged water-erosion. The 
northern and western portions of the State belong practically 
to the great prairie region of the interior. 

None know just where the old outlet to Lake Winnepe- — 
saukee in New Hampshire is; but, from the nature of the 
situation and the analogies of the case, there can be no 
doubt that it, together with the most of the larger lakes of 
New England, is held in place by deposits of glacial material 
fillmg up an old outlet. Doubtless, with comparatively little 
labor, trenches might be dug which should, when not below 
the ocean, drain them all to the bottom. There can be no 
doubt, also, that Lake Champlain and Lake George are held 
in their elevated positions by similar glacial dams, and such 
is certainly the case with many of the numerous lakes which 
dot the glaciated region of northern New Jersey. Toa 
similar origin is due the remarkable series of parallel lakes 
in central New York, having at the present time a common 
outlet in the Oswego River. Chautauqua Lake, now flowing 
over a rocky bed past Jamestown into the Alleghany, is one 
of the most elevated of this class of glacial lakes, being held 
in place by a vast glacial deposit filling up the mouth of an 
old outlet into Lake Erie. 

The evidence that Lake Erie is caused by the damming 
up of the old outlet of the valley by glacial débris, has 
already been presented, and the importance of this fact will 
appear when we come to discuss the date of the Glacial 
period. 

But, interesting as are these more permanent dams of the 
Glacial period, they must yield supremacy to the temporary 
lakes formed by the ice-barrier itself in its various adjust- 
ments to the topography of the country. Travelers in the 
Grindelwald Alps have their attention frequently directed 
to the diminutive specimens of such lakes still existing 


364 THE ICE AGE IN NORTH AMERICA, 


there. The following accurate and interesting account of 
them is from the pen of Professor William M. Davis: * 


Glacial lakes are now of little importance ; a few occur in 
the higher mountain-chains, but they are trifling in size, and 
rank with many other species only as curiosities unless they 
become of disastrous importance in the valleys below, from the 
floods that follow a giving way of their barriers. Three sub- 
species: are easily distinguished : First, when the advance of a 
glacier down a main valley closes the mouth of a lateral ravine ; 
_ second, when a glacier from a side valley obstructs the main 
stream ; third, when the great ice-sheet of early Quaternary 
times saad away so as to disclose the upper part of a valley 
sloping gently against it. 

The Merjelen See in Switzerland serves as the type of the 
first subspecies ; it is held back by the Great Aletsch Glacier 
in a little valley behind the Eggischhorn, a favorite point of 
view, from which the lake below and the whole stretch of the 
ice-stream in the main valley can be seen. Sometimes the 
waters find an outlet through the ice-barrier ; then the slow 
accumulation of months rushes out in a torrent, flooding the 
valley of the Massa below, and leaving miniature bergs broken 
from the glacier stranded on the rocky bottom ; subsequently, 
another motion of the glacier closes the outlet, and the basin 
slowly fills again. ‘The highest level of such a lake will be 
. determined either by free escape across the ice, when it will 
have a variable maximum, or by flow over a pass at the head 
of its lateral valley. The latter is the case with the Merjelen 
See, and the level of the pass is marked by a faint terrace and 
by a change of color on the rocks around the shore. f 
_ Although rare at present, these lakes have had a consider- 
. able importance in the. past. An extinct example was early 
recognized by Agassiz at the Parallel Roads of Glen Roy, near 
Ben Nevis, in Scotland ;{ these are simply the shore-line 


* “Proceedings of the Boston Society of Natural History,” vol. xxi, pp. 
$50, 351. 

+L. Agassiz, “Etudes sur les Glaciers” (1840), pp. 218, 220. Lyell, 
“Principles of Geology,” vol. i, p. 372; “ Antiquity of Man,” p. 309. 

+ Agassiz, “Geological Society Proceedings,” vol. iii, 1842, p. 331; here 
described as a lateral glacier closing the main valley. 


ai 


GLACIAL DAMS, LAKES, AND WATERFALLS. 365 


terraces of an old ice-barrier lake, the uppermost standing at 
the height of the pass into the next glen, but the cause of ,the 
others is not so apparent ;* the glacier which served as a bar- 
rier has long since disappeared, with all its Scotch com- 
panions. 

The Mattmark See, representing the second subspecies, is in 
the Saas valley, between Monte Rosa and the Rhéne, where 
the Allalin Glacier advances across the main valley bottom. + 
It differs from the preceding only in the relative position of 
lake and barrier, and in the lake’s level always being deter- 
mined by flow over the ice or its moraine. The Lac du 
Combal is in the same way held back by the Glacier de Miage 
at the southern base of Mont Blanc. Several temporary Swiss 
lakes of this construction have caused great damage by burst- 
ing through their barriers. A.famous case is that of the 
Gietroz Glacier in the valley of Bagnes, south of Martigny, in 
1818. The lake grew to be a mile long, seven hundred feet 
wide, and two hundred deep. An attempt was made to drain 
it by cutting through the ice, and about half the water was 
slowly drawn off in this way ; but then the barrier broke, and 
the rest of the lake was emptied in half an hour, causing a 
dreadful flood in the valley below.{ In the Tyrol, the Vernagt 
Glacier has many times caused disastrous floods by its inability 
to hold up the lake formed behind it.* In the northwestern 
Himalaya, the upper branches of the Indus are sometimes held 
back in this way. A noted flood occurred in 1835 ; it advanced 
twenty-five miles in an hour, and was felt three hundred miles 
down-stream, destroying all the villages on the lower plain, 
and strewing the fields with stones, sand, and mud. || 


* Lyell, “ Antiquity of Man,” p. 300. A good bibliography of this old lake 
is given by W. Jolly, in “ Nature,” May 20, 1880, p. 68. 

+ Heliotypes of this and the Merjelen See are given in “ Glaciers,” by Shaler 
and Davis, Boston, 1881. 

t Lyell, ‘‘ Principles,” vol. i, p. 348. ‘‘ Bibliothéque Universelle de Genéve,” 
vol. xxi, 1827, p. 227; vol. xxii, p. 58; vol. xxv, p. 24, etc. 

#* Sonklar, “Die Oetzthaler Gebirgsgruppe,” Gotha, 1860, p. 154. Stotter, 
“Die Gletscher des Vernagtthales in Tirol und ihre Geschichte,” Innsbruck, 
1840, p. 15. 

|| H. Strachey, “ Royal Geographical Society Journal,” vol. xxiii, 1853,.p. 55. 
Compare Drew, Jummoo, and Kashmir. 


366 THE ICE AGE IN NORTH AMERICA. 


Mr. J. E. Marr, in recording his observations upon the 
Jakobshavn Glacier, gives the following account of the gla- 
cial dams connected with it: 


The Jakobshavn Glacier stops up both ends of a valley, 
running parallel with its course, converting it into a lake, 
which is separated from the glacier throughout the greater 
part of its length by a nunatak.* The lower end of another 
valley considerably to the south of this is stopped by the ice- 
sheet, and the valley converted into a lake (Tasersiak), which 
is drained by a river running over the col at the head of the 
valley into the Strom Fiord, just as in the case of the Merjelen 
See, only the Greenland lake is much larger than this. <A 
similar lake drains into the North Isortok Fiord, and another 
into that of Alangordlia. ‘Two similar lakes are formed to the 
east of Sermilik Fiord, and several small ones to the east of 
Bjornesund. North of the Frederikshaab Glacier is a valley 
running north and south, the mouth of which is stopped by 
the Frederikshaab Glacier, while a tongue of ice flows through 
a col situated half-way up the valley and bars the valley, one 
part of the tongue of ice flowing a small distance to the north 
and another to the south, thus causing the conversion of the 
valley into two lakes. On the east of the Frederikshaab Gla- 
cier is the Lake Tasersiak, bounded on the north by the 
nunatak Kangarsuk, and stopped at its lower end by the Fred- 
erikshaab Glacier, and having a tongue of the ice-sheet en- 
tering into it at the upper end. ft 


With these facts concerning existing glacial dams in 
mind, we are prepared to study the signs of similar obstruc- 
tions, on a larger scale, which occurred during the progress 
of the Glacial period. We will first present the facts relat- 
ing to a supposed obstruction by glacial ice, of the Ohio 
River at Cincinnati. 

In the summer of 1882, after having the previous year 
completed, with Professor Lewis, the exploration of the gla- 


* See p. 79. 
+ “ Geological Magazine ” for April, 1887, quoted in the ‘‘ American Journal 
of Science,” vol. cxxxiv, 1887, p. 313. 


GLACIAL DAMS, LAKES, AND WATERFALLS. 367 


eial boundary through Pennsylvania, I continued the work 
through the State of Ohio, and traced the line at length to 
the Ohio River, near Ripley, about sixty miles above Cincin- 
nati. From this point, for about thirty miles down the river, 
to the vicinity of New Richmond, the glacial boundary lies 
upon the north bank of its trough; till, bowlders, and 
scratched stones being found on the highlands down to the 
extreme margin on the north side, but being absent from 
the corresponding highlands on the Kentucky side. Near 
Point Pleasant, the birthplace of President Grant, the river 
makes a long bend to the north, continuing in this direction 
to Cincinnati, and thence westward to North Bend, the 
home and burial-place of President William Henry Har- 
rison ; here it turns south again, thus forming in Kentucky 
a peninsula, as it were, pointing to the north, and including 
the territory of Campbell, Kenton, and Boone counties. 
Upon examining this district it was found that in places in 
Campbell county, and over the whole northern and western 
parts of Boone county, there were true glacial deposits on the 
highest lands—the elevation near Burlington being five hun- 
dred and fifty feet above low-water mark at Cincinnati. In 
places, large numbers of bowlders of northern origin were 
found stranded on the very summit-level of the region—i. e., 
on the divide, between the short streams running north and 
those running south, and between the Licking and the Ohio 
River. They were also found south of this secondary di- 
vide, seven miles back from the river, and five hundred feet 
above it (near Florence, Boone county). Several were recog- 
nized as belonging to a species of red jasper conglomerate, 
whose outcropping is well marked on the northern shore of 
Lake Huron and about the outlet of Lake Superior. These 
powlders are very beautiful ; and, farther north, where they 
are more abundant in the fields, are frequently used to adorn 
the front-yards of residences or even for the construction of 
public buildings. Some of the citizens of Cleveland, Ohio, 
have brought large fragments for this purpose from the par- 
ent ledges. But here, beside a roadway through the Ken- 


368 THE IO AGE IN NORTH AMERICA, 


tucky hills, were large specimens of this same conglomerate 
(one bowlder being nearly three feet in diameter), which had 
been transported by glacial ice fully six hundred miles from 
their native bed, and left to tell the story not only of their 
own travels, but of other most interesting events connected 
with the cause which transported them. These glacial de- 
posits south of the Ohio are such as to make it certain that 
the front of the continental glacier itself pushed, at some 
points, seven or eight miles beyond the Ohio River; and it 
is altogether probable that for a distance of fifty miles (or 


Fre. 108.—Conglomerate bowlder found in Boone County, Kentucky. (See text.) 


completely around the eastern, northern, and western sides of 
the Kentucky peninsula formed by the great bend of the 
river), the ice came down to the trough of the Ohio, and 
crossed it so as completely to choke the channel, and form a 
glacial dam high enough to raise the level of the water five 
hundred and fifty feet—this being the height of the water- 
shed to the south. The consequences following are inter- 


esting to trace. | 
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310 THE ICE AGE IN NORTH AMERICA. 


above the sea-level. A dam of 568 feet would raise the 
water in its rear to a height of 1,000 feet above the tide. — 
This would produce a long, narrow lake, of the width of the 
eroded trough of the Ohio, submerge the site of Pittsburg 
to a depth of 300 feet, and make slack water up the Monon- - 
gahela nearly to Grafton, W. Va., and up the Alleghany as - 
far as Oil City. All the tributaries of the Ohio would like- 
wise be filled to this level with the back-water. The length 
of this slack-water lake in the main valley, to its termination 
up either the Alleghany or the Monongahela, was not far 
from one thousand miles. The conditions were also peculiar 
in this, that all the northern tributaries head within the south- 
ern margin of the ice-front, which lay at varying distances to 
the north. Down these northern tributaries there must have 
poured during the summer months immense torrents of water 
to strand bowlder-laden icebergs on the summits of such high 
hills as were lower than the level of the dam. 

The facts leading to this conclusion, together with the 
theory itself, were first published by me in the “ American 
Journal of Science” for July, 1882.* At the conclusion I 
added that “it remains to be seen how much light this may 
shed upon the terraces which mark the Ohio and its tribu- 
taries in western Pennsylvania.’’ Soon after this I received 
from Professor I. C. White, of Morgantown, W. Va. (whose 
long experience and careful work upon the Pennsylvania 
Geological Survey has made his name a synonym for accu- 
racy of observation and skill in drawing conclusions), a letter 

stating that the theory of an ancient ice-dam at Cincinnati 
was the key to unlock what had heretofore been a great puz- 
zle to the Pennsylvania geologists. Briefly told, the progress 
of the discovery and discussions concerning it are as follows : 

On all the upper tributaries of the Ohio there are high- 
level terraces in abundance which the local geologists could 
with difficulty explain. Upon comparison, however, an im- 
portant portion of the series was found to have very nearly 


* “ American Journal of Science,” vol. exxvi, pp. 1-14. 


GLACIAL DAMS, LAKES, AND WATERFALLS. 371 


the same absolute elevation above the sea-level with that of 
the assumed top of the glacial dam at Cincinnati. At my 
request, Professor I. C. White prepared a paper to be read 
at the meeting of the American Association for the Advance- 
ment of Science at Minneapolis in the summer of 1883. In 
this paper the facts concerning the terraces in the valley of 
the upper Ohio were set forth, together with their bearing 
upon the existence of the supposed glacial dam. The Min- 
neapolis meeting was remarkable for the number of distin- 
guished geologists present who had given special attention to 
glacial phenomena. Among them was Professor Lesley, who 
has been for so many years the organizing mind of the Penn- 
sylvania Geological Survey. When the subject of the Cin- 
cinnati ice-dam was brought up by the reading of Professor 
White’s paper, Professor Lesley at once gave his adhesion to 
the theory, and frankly stated that what he had written some 
years before in explanation of the terraces in western Penn- 
sylvania was entirely superseded. He had then, in order to 
account for the terraces, resorted to the hypothesis of a gen- 
eral subsidence of the region to the extent of several hundred 
feet. But later he had himself perceived the inadequacy of 
such an hypothesis, since there were not, as upon this suppo- 
sition there should be, corresponding terraces upon the east 
side of the Alleghany Mountains. He had therefore ex- 
pressed the belief that some local obstruction would be dis- 
covered in the lower part of the Ohio which would account 
for the facts. ‘“ And now,” said he, “ Providence has pro- 
vided one, and Wright’s dam will explain it all,’ and went 
on to show that the absence of similar terraces on the east 
side of the mountains was fatal to the theory of a continental 
subsidence, while it was just what would be expected on the 
theory of an obstruction of the drainage of the upper Ohio. 

A theory of such wide significance is not, however, to be 
too hastily accepted, and much attention has since been di- 
rected toward its verification or disproval. 

In presenting the evidence upon this subject it is well to 
remark that the study of river terraces brings to light a com- 


a7). THE ICE AGE IN NORTH AMERICA, 


plex action of forces often difficult to unravel, and peculiarly: 
liable, in a case like this, to lead one astray. Hence it is 
probable that a part of the testimony in favor of the Cincin- 
nati ice-dam, drawn at first from the terraces of the upper 
Ohio, was irrelevant, since some of. the terraces were doubt- 
less due to the natural progress of river-erosion. For ex- 
ample, where streams flow down from the flanks of a mount- 
ain-chain, and have considerable opportunity to deepen their 
channels, they leave gravel deposits at various levels, and oc- 
casionally abandon some portion of their old bed to occupy 
a shorter and deeper cut-off. Upon examination of the 
Monongahela and its branches, it would seem that several of 
the terraces at first attributed to the effect of the glacial dam - 
at Cincinnati were formed in the manner thus indicated, or 
may have been so formed. In this case their remarkable 
correspondence with the height of the supposed obstruction 
at Cincinnati is one of those accidental coincidences that are 
often met with in nature. After eliminating, however, all 
such cases, there remains a constantly increasing residuum 
of facts which fairly refuse to be explained, except on the 
theory supposed. 

Beginning with one of the clearest cases, attention is di- 
rected to the head-waters of Brush Creek, in Pike county, 
Ohio. By reference to the accompanying map it will be 
seen that at the height of the Glacial period the front of the 
ice rested at the northwest corner of this county. A more 
accurate study of the details shows that the divide between 
Paint Creek and Baker’s Fork of Brush Creek is formed by 
the extreme portion of the terminal moraine. Before the 
Glacial period there was a continuous depression connecting 
Paint Creek with the valley of Brush Creek. At a point 
about five miles south of Bainbridge, on Paint Creek, in 
Ross county, this depression is filled wp, from side to side, 
to a height of about two hundred feet, with a glacial deposit 
containing numerous northern bowlders and scratched stones. 
On the northern side, toward Paint Creek, this deposit ex- 
hibits every mark of a terminal moraine, with its character- 


GLACIAL DAMS, LAKES, AND WATERFALLS. 373 


istic knobs, ridges, and kettle-holes ; while to the south of it 
there is an extensive plain known in the locality as the Beech 


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Fig. 110— Map of a portion of the glacial boundary in southern Ohio, showing its relation 
to Paint Creek cut-off and to Beech Flats, at the head-waters of Ohio Brush Creek. 
The general elevation of the unglaciated region is from three hundred to five hun- 
dred feet above the river-bed. The terraced valley of the Scioto River is approxi- 
mately indicated by the dotted line. The old valley of Paint Creek, now choked up 
by glacial déhris. ran around by Slate Mills. Thesmail stream coming in at the angle 
of the cut-off is the one from which an estimation of time is made in chapter xx, 


page 561. 


Flats. This, too, consists largely of transported material from 
the north ; but it is mostly fine like loess, and level-topped, 
and is about one hundred feet higher than the valley of 
Baker’s Fork, which heads in it and runs to the south, empty- 
ing into the Ohio River. 


374 THE ICE AGE IN NORTH AMERICA. 


It is evident that, while the ice-front rested over the 
northwestern portion of Pike county, and was depositing the 
terminal moraine just described, there ought to have been, 
during the whole time, a strong current of glacial drainage 
rushing down through Baker’s Fork into Brush Oreek, de- 
positing more or less of overwash gravel along its bed. But 
there are no marks of such a line of glacial drainage here. 
There are no terraces on Baker’s Fork ; and no granitic peb- 
bles are to be found in its valley, where they ought to exist 
in great numbers if there had been a glacial torrent pouring 
into it from the terminal moraine. The uniformity with 
which these lines of glacial drainage are marked by terraces, 
and by the presence of northern pebbles gathered from the 
glaciated region, is, as we have already seen, one of the most 
striking features just outside the glaciated region all the way 
from the Atlantic Ocean to the Mississippi River. For the 
exception in the present instance there would seem to be but 
one explanation, and that is as complete as it is unexpected. 
The ice-dam in the Ohio River, supposed on other evidence 
to have been in existence for a short time at the climax. of 
the Glacial period, perfectly accounts for this exceptional 
phenomenon, while no other adequate cause whose existence 
is at all probable can be found. The explanation is as fol- 
lows : 

The height above the tide of this moraine, which closes 
up the opening between Paint and Brush Creeks, is between 
nine hundred and a thousand feet, corresponding very closely 
with the supposed height of the water-level produced by the 
ice-dam at Cincinnati. Hence, during the existence of the 
dam, there would have been no chance for the formation of 
a glacial torrent down Brush Creek, since back-water extended 
to the very ice-front at its head, and the terminal deposit was 
laid down in still water. The limitations of this deposit at 
the head of Baker’s Fork and the level surface of Beech 
Flats, therefore, furnish a complete verification of the theory, 
and prove beyond question the reality of the Cincinnati dam. 

Furthermore, the lower portion of Paint Creek is so situ- 


GLACIAL DAMS, LAKHS, AND WATERFALLS. 375 


ated with reference to the glacial boundary that its mouth 
was for a time obstructed by the ice ; but, when the ice-front 
had withdrawn two or three miles, drainage would again be 
opened into the Scioto, and at a level which is a hundred 
feet or more lower than the surface of the moraine between 
Paint and Brush Creeks, so that the natural necessity for a 
glacial outlet down Brush Creek would exist only so long as 
the ice closed up the mouth of Paint Creek. From this de- 
scription of the situation it becomes evident that, so soon as 
the ice should have retreated from the Kentucky hills south 
of Cincinnati, so as to raise the blockade and reopen the chan- 
nel of the Ohio, it would doubtless also have retreated from 
the mouth of Paint Creek ; and the line of glacial drainage 
through that into the Scioto, and thence down the reopened 
Ohio, would have been re-established. 

A theory which so naturally accounts for so complicated 
a set of facts as these is well-nigh proved by this single in- 
stance. The only competing hypothesis possible is that of a 
general subsidence of the country producing the same water- 
level above Cincinnati which the ice-dam is supposed to have 
done. But such a theory lacks the positive evidence addu- 
cible for a glacial dam at Cincinnati; and, besides, it is not 
probable that a general depression of the country, such as 
would produce still water at the head of Brush Creek, would 
be of such short duration as is implied by the facts connected 
with this deposit. The gradual lowering of a barrier holding 
the water at that height would have caused numerous benches 
on the interior of the deposit toward the ice, whereas the 
terrace on that side is even more abrupt than on the other. 

A second class of facts supporting the theory of the Cin- 
cinnati ice-dam is drawn from the high-level terraces found in 
the trough of the upper Ohio and its main tributaries. One of 
the most significant of these occurs at Bellevue, on the north 
side of the Ohio River, five miles below Pittsburg, where a 
terrace is found about a mile long, half a mile wide, and fifty 
or sixty feet in depth, preserved upon a shelf of rock facing 
the river perpendicularly, and between two hundred and 


376 THE ICE AGE IN NORTH AMERICA. 


fifty and three hundred feet above it. The material of this 
high-level terrace consists largely of gravel and pebbles de- 
rived from the glaciated region, granitic pebbles being abun- 
dant init. It must therefore have been deposited since the 
ice came over into the head-waters of the Alleghany. Two 
theories are offered to account for this: One assumes the 
reality of the ice-dam at Cincinnati, and sees in this terrace 
a natural result of that obstruction. Bellevue lies in the 
lower angle formed by the junction of the Ohio and Alle- 
ghany Valleys; and the summit of the terrace under consid- 
eration corresponds closely in altitude with the elevation of 
the Cincinnati dam ; and here, in the eddy below the mouth 
of the Alleghany, at the beginning of the larger valley of 
the Ohio, was the natural place for the accumulation of 
bowlder-laden masses of ice brought down from the glacier’s 
front by the periodical floods of the Alleghany. 

If we leave the theory of general submergence out of 
account, the only other way to explain this accumulation is 
to regard it as a portion of a deserted river valley when the 
stream occupied a rocky bed more than three hundred feet 
above its present level. This would require a lapse of time, 
since the deposit was made, sufficient to allow the Ohio and 
all its tributaries to lower their rocky beds, for many hun- 
dred miles, to a depth of more than three hundred feet. As 
we shall see, later on, it seems to be entirely out of the ques- 
tion to suppose any such lapse of time since the last glacial 
period, for the Niagara gorge has receded only seven miles 
since then. But resort may be had to the supposition of a 
previous glacial period, during which the ice also came over 
into the head-waters of the Alleghany, and, indeed, every- 
where came down nearly to the limits of the glaciated region 
in Pennsylvania and Ohio already delineated. On this sup- 
position the time intervening between the first and the last 
glacial period would be equal to that required by the Ohio 
and its tributaries to lower their rocky beds at least three 
hundred or four hundred feet. This enormous lapse of time 
would carry us back, in all probability, well-nigh to the be- 


GLACIAL DAMS, LAKES, AND WATERFALLS. 377 


ginning of the Tertiary period. But, that no such length of 
time can have elapsed since these upper terraces were depos- 
ited, may be inferred from their structure and situation in 
various other places. For example, vegetable and animal 
remains of recent species are found in a very fresh state of 
preservation in river deposits of the Ohio Valley correspond- 
ing in age with the terraces in question. 

The first instance of this to be mentioned is one which 
has been carefully investigated and described by Professor 
I. C. White, and occurs on the Monongahela River, near 
Morgantown, W. Va. The trough of the Monongahela, 
which joins the Alleghany at Pittsburg to form the Ohio, 
is in every way similar to that of the Alleghany, with the 
single exception that the terraces which line its banks at 
heights corresponding to those of the Alleghany and upper 
Ohio, contain no pebbles of northern drift, but consist wholly 
of material which is native to the valley itself. At numer- 
ous places along the Monongahela there are extensive depos- 
its of pebbles and bowlders from two hundred to three hun- 
dred feet above the river, especially near where tributaries 
enter. In many of these deposits there is nothing to indi- 
eate their age; but, at Morgantown, W. Va., there would 
seem to be a decisive case, showing the comparatively recent 
date of the deposition of this series of terraces. The follow- 
ing is Professor White’s description : 


Owing to the considerable elevation—275 feet—of the fifth 
terrace above the present river-bed [in the vicinity of Morgan- 
town], its deposits are frequently found far inland from the 
Monongahela, on tributary streams. A very extensive deposit 
of this kind occurs on a tributary one mile and a half north- 
east of Morgantown ; and the region, which includes three or 
four square miles, is significantly known as the “ Flats.” The 
elevation of the ‘‘ Flats” is 275 feet above the river, or 1,065 
feet above tide. The deposits on this area consist almost en- 
tirely of clays and fine, sandy material, there being very few 
bowlders intermingled. The depth of the deposit is unknown, 
since a well sunk on the land of Mr. Baker passed through 


378 THE ICE AGE IN NORTH AMERICA. 


alternate beds of clay, fine sand, and muddy trash to a depth 
of sixty-five feet without reaching bed-rock. In some portions 
of the clays which make up this deposit, the leaves of our 
common forest-trees are found most beautifully preserved. 
Whether or not they show any variations from the species 
growing in that region, the writer has not yet had time to 
determine ; but, when a larger collection has been obtained, 
this subject will receive the attention that it deserves, since, 
if the date of the Glacial epoch be very remote, the species 
must necessarily show some divergence from the present flora. 
Of animal remains the only fragments yet discovered in this 
highest of the terraces is the tooth of a mastodon, dug up near 
Stewartstown, seven miles northeast from Morgantown. 


As the relation of this deposit near Morgantown to others 
farther up the river is important, we quote also from the sup- 
plementary statement of facts made by Professor White in a 
paper presented at the meeting of the American Association 
for the Advancement of Science at Buffalo, in 1886: 


In the region of Morgantown, on the main Monongahela, 
these terrace deposits end at about 275 feet above low water, 
or 1,065 feet above tide; while at Fairmount, twenty-six 
miles above, there is a vast amount of this terrace material 
thrown down about the junction of the Valley and West Fork 
Rivers, and the upper limit of the same is a little over two hun- 
dred feet above low water, which is here 850 feet above tide. 
About twenty miles farther up the river (West Fork), near 
Shinnston, the upper limit of the terrace material is found at 
160 feet above the water, but here the latter has an elevation 
of about 885 feet above tide. 

At Clarksburg, where the river unites with Elk Creek, there 
is a wide stretch of terrace deposits, and the upper limit is there 
about 1,050 feet above tide, or only 130 feet above low water 
(920 feet) ; while at Weston, forty miles above (by the river), 
these deposits cease at seventy feet above low water, which is 
there 985 feet above tide. It will thus be observed that the 
upper limit of the deposits retains a practical horizontality 
from Morgantown to Weston, a distance of one hundred miles, 


GLACIAL DAMS, LAKES, AND WATERFALLS. 379 


since the upper limit has the same elevation above tide (1,045 
to 1,065 feet) at every locality. 

_ These deposits consist of rounded bowlders of sandstone, 
with a large amount of clay, quicksand, and other detrital 
matter. The country rock in this region consists of the soft 
shales and limestones of the upper coal-measures, and hence 
there are many ‘‘low gaps” from the head of one littie stream 
to that of another, especially along the immediate region of the 
river ; and in every case the summits of these divides, where 
they do not exceed an elevation of 1.050 feet above tide, are 
covered with transported or terrace material ; but where the 
summits go more than a few feet above that level we find no 
transported material upon them, but simply the decomposed 
country rock. 

A fine example of one of these bowlder-covered divides. may 
be seen at the mouth of the Youghiogheny River, back of Mc- 
Keesport, Pa. The “divide” in question is one between the 
water of Long Run, which puts into the Youghiogheny, two 
miles above McKeesport, and that of another little stream 
which heads up against it, and flows into the Monongahela 
within the city limits. The divide between these two water- 
ways. although 275 feet above the Jevel of the river, is almost 
imperceptibie in a broad and bowlder-covered valley through 
which there is not the slightest doubt that the waters of the 
Youghiogheny once flowed during an epoch of submergence.* 


Passing farther down the Ohio Valley, we find a most 
interesting exhibition of this high-level slack-water depo- 
sition in Teazes Valley, Putnam county, W. Va. This val- 
ley rens from the Kanawha River, a little below Charleston, 
to the Ohio at the mouth of the Guyandotte, near Hunting- 
ton. The valley is clearly enough a remnant of the early 
erosion which sculptured the whole country. The water of 
the upper Kanawha evidently at one time took this course 
to the Ohio. The valley is very clearly marked, and its 
main features can be taken in by any one riding over the 


Chesapeake and Ohio Railroad between Huntington and 


* “ American Journal of Science,” vol. exxxiv, 1887, pp. 378, 379. 


380 THE ICH AGH IN NORTH AMERICA. 


Charleston. It is about a mile wide, and from two hundred 
to three hundred feet lower than the hills on either side, and 


Fie. 111.—Section of the deposit at Long Level, in Teazes Valley, West Virginia. ‘The 
puried piece of wood referred to in the text was about the middle of the cut on dig- 
ging into the perpendicular face of the bank. 


has a remarkably level floor throughout the greater part of 
its course. The bottom of the valley is filled throughout 


GLACIAL DAMS, LARES, AND WATERFALLS. 381 


with a deposit of river-pebbles covered many feet deep with 
a mixture of sand and clayey loam. In some places this loam 
is from thirty to forty feet deep, extending for several miles 
without interruption, as at Long Level, about the middle of 
the valley. Here a section, about half a mile long and twenty- 
five feet deep, shows at the top a stiff stratum of clay con- 
taining wood at a depth of seven feet. Immediately below 
is sand cemented together by the infiltrations of iron. The 
stratum above, containing the wood, had never been disturbed, 
and the wood is remarkably fresh in its whole appearance. 
It is searcely possible that it should have remained in such a 
position during all the time required for the erosion of the 
Ohio Valley and its tributaries from the level of Teazes Val- 
ley to its present level, two hundred and fifty feet below. 
Besides, there are many other things to show that the deposit 
was in slack water rather than on the flood-plain of a running 
stream. Unlike the deposit of a river on its banks, in this 
ease the silt extends clear across the valley, covering every- 
thing to a uniform depth, except where it has been removed 
by subsequent irregular erosion. 

Another evidence of the recent date of this deposit of 
river-silt in Teazes Valley, as compared with the erosion of 
the valley itself, appears in the relation of the transverse 
water-ways to it. Mud River and Hurricane Creek are two 
small streams rising some little distance to the south, but 
now either joining the valley, or crossing it at a level sixty 
or seventy feet lower than that of its rocky bottom. Mud 
River joins it at Milton, and then turns west and follows its 
course to the Guyandotte. But the level of Mud River, 
even where it now joins the valley, is one hundred and 
twenty feet lower, and this in a channel worn in the solid 
sandstone rock. Hurricane Creek is a still smaller stream, 
and crosses the valley within a few miles of its eastern end, 
emptying into the Kanawha some miles lowerdown. Where 
this small stream crosses Teazes Valley its bed is sixty or 
more feet lower down in the rock than that on which the 
pebbles and silt rest throughout the valley, and these de- 


382 THE ICE AGE IN NORTH AMERICA. 


posits come down on the rocky shelf bordering the Hurri- 
cane in a way to show that it could not have remained where 
it is during the time required for so small a stream to wear 
down so large and deep a channel. | 

The extension of Teazes Valley, after merging for a 
short distance with the Ohio, really continues back of Ash- 
land, Ky., on the south side of the river, down as far as 
opposite Hanging Rock in Ohio, in alla distance of about 
sixty miles. 

Among other decisive instances discovered by Professor 
White, and bearing on the recent date of these high-level 
terrace deposits, are the following : 


About ten miles above the mouth of the Big Sandy River, 
and on the West Virginia side, a considerable deposit of small 
water-worn bowlders occurs near the summit of a broad, flat- 
topped hill, at an elevation of four hundred feet above the 
stream, or not far from nine hundred feét above tide. This 
deposit is interesting from the fact that it is the only one that 
I was able to find between the point in question and the source 
of the river, nearly two hundred miles above, though the fail- 
ure may be satisfactorily accounted for in the precipitous char- 
acter of the bounding valley-walls, and the unusually soft and 
easily disintegrating nature of all the surface-rocks ; for along 
the Big Sandy even the Pottsville conglomerate becomes rot- 
ten, and very readily crumbles into loose sand, which, carried 
down by the rain, fills up the channel of the river, and has 
thus given name to the stream. It is not assuming to state 
that these rounded bowlders of local coal-measure sandstone 
could hardly have resisted the elements during the long time 
since the Big Sandy Valley existed at this 400-foot level. 

The Guyandotte River puts into the Ohio next above the 
Big Sandy, and on this stream, about one hundred miles above 
its mouth, a large deposit of rounded bowlders was observed 
on the inner side of one of its great curves opposite the mouth 
of Panther Creek. The bowlders cease at 150 feet above the 
stream, or about 925 feet above tide, according to levels run by 
Captain Miller, of the Trans-Flat Topland Company. The 
bowlder-deposits are found in greatest quantity about the 


GLACIAL DAMS, LAKES, AND WATERFALLS. 383 


junction of streams, and consequently at the mouth of Elk 
River, on the Great Kanawha, in the vicinity of Charleston, 
vast numbers of them extend to near 250 feet above this river 
(800 feet above tide), and scattering ones are found up to 390 
feet (or 945 feet above tide). Here, along with the hard rocks 
of local origin, we find great numbers that have come from the 
Blue Ridge in Virginia and North Carolina, nearly two hun- 
dred miles distant. 

I shall not be surprised if some of my readers regard this 
theory of an ice-dam at Cincinnati as visionary ; and, indeed, 
I do not myself present it as established with the same de- 
gree of certainty with which the more general facts relating 
to the Ice age are established. Still, I am confident that 
close reflection upon the evidence already presented will be 
sufficient to produce conviction to most minds. The bowl- 
ders found south of the Ohio River, opposite Cincinnati, are 
too large to have been carried except by ice, and they are so 
high above the river, and so far back from it, that floating 
ice could not have been the agent of transportation, except 
the channel itself were obstructed. Nor is there any im- 
probability arising from the nature of the case against such 
an obstruction by ice. For, through a distance of nearly 
fifty miles, the ice certamly came down to the northern side 
of the trough. In much broader valleys than this the ordi- 
nary ice-gorges during a spring freshet produce remarkable 
results, raising the water to a great height. But the course 
of the Ohio at Cincinnati is such as to invite gorges upon the 
largest scale; and, with a moving ice-front behind, a perma- 
nent closure is not improbable. If one should surmise that 
a depth of five hundred feet of water would lift the ice in 
the channel so as to secure a subglacial outlet, it should be 
remembered that the specific gravity of ice is such that it 
would require more than a depth of six hundred feet of 
water to lift a body of ice which was seven hundred feet 
thick ; and the bowlders on the south side of the river are so 
far distant, the one of which we give a cut being seven or 
eight miles south of the river, that the ice was donbtless 


384 THE ICE AGE IN NORTH AMERICA. 


considerably more than a hundred feet above the top of the 
trough at Cincinnati. 

Bringing to mind the other considerations, we think no 
one can doubt that the trough of the Ohio was mainly 
formed before the Glacial period. This we infer from the 
enormous lapse of time during which the river had been at 
work, viz., from the first elevation of the continent to the ear- 
liest date aacianad by any to a glacial period in North Amer- 
ica. With this trough formed, the problem of accounting 
for the terrace at Bellevue, below Pittsburg, containing gra- 
nitic pebbles is a most difficult‘one, except upon the theory of 
this ice-dam. The granitic pebbles mark it as connected 
with the Glacial period, and its height (three hundred feet 
above the river) renders it impossible of explanation on any 
other theory than one which assumes an incredible lapse of 
time since the deposit was made. The small extent to which 
the material of this terrace has been oxidized and disinte- 
grated, indicates no such enormous lapse of time; while the 
terraces in the Monongahela River, which Professor White 
describes as containing freshly preserved leaves at great 
depths, and the terraces in the neighborhood of the Big 
Sandy, containing pebbles peculiarly liable to disintegration, 
confirm the inference of the comparatively recent origin of 
a series of terraces in the upper Ohio, closely correspond- 
ing to the level of the Cincinnati ice-dam. To these con- 
siderations, also, are to be added those concerning Beech 
Flats, between the southwestern angle of Paint Creek and 
the head-waters of Brush Creek. Altogether this would 
seem sufficient to give a high degree of probability to the 
theory, and to justify the wide acceptance which has been 
given to it by the eminent geologists most familiar with 
the region. 

In presenting this brief summary of evidence bearing on 
the existence of the Cincinnati ice-dam, however, I am far 
from cousidering the discussion of the theory closed. It 
remains for local observers, first, to comprehend the facts 
already presented, and then to test the hypothesis in every 


GLACIAL DAMS, LAKES, AND WATERFALLS. 385 


legitimate manner possible. The field is a most inviting one, 
and will assuredly yield abundant fruits. 

Among other requirements made upon the theory it has 
been demanded that I should point out the outlet of the 
pent-up waters. But this I am not able at present to do. I 
have had neither the time nor the opportunity to explore the 
region south of Cincinnati sufficiently to say certainly where 
it was; nor have I come to a negative conclusion, so that I 


Fic. 112.—Spiit Rock. A conglomerate containing granitic pebbles. In Boone County, 

ata a(aee etl miles below Cincinnati, one hundred and sixty feet above 
can say that there is none to be found; nor do i know that 
any one else has done so. Professor Claypole is inclined to 
think Mr. Squier * has indicated the locality of the old outlet 
in some of the passes in the vicinity of Owingsville and 
Mount Sterling leading from the upper waters of the Lick- 
ing River into the valley of the upper Kentucky. From 


* See letter in “Science,” September 28, 1883; for additional facts, see the 
author’s “‘ Glacial Boundary in Ohio, Indiana, and Kentucky,”’ p. 86 


386 THE ICE AGH IN NORTH AMERICA. 


Gannet’s table of levels, which is very scanty in that portion 
of Kentucky, it would appear that the height of the water- 
partings between the Licking and the Kentucky is not 
greater than that of the ridge running south from Cincinnati 
between the Licking and the Ohio; so that such an outlet 
may exist somewhere in that vicinity. 

But I have not been sure that the water did not pass 
around the immediate margin of the ice reaching the Ohio at 
the mouth of Woolper Creek, about thirty miles below Cin- 
cinnati, where the celebrated post-glacial conglomerate known 
as Split Rock is situated. This formation consists of pebbles 
now firmly cemented together by intiltrations of lime. The 
mass rises one hundred and sixty feet above the river. The 
most of the pebbles are limestone from the Cincinnati group, 
but there are mingled with them granitic pebbles which 
show it to be a glacial deposit. On Middle Creek, a little 
lower down in Boone county, the same conglomerate is found 
at a still higher level, running up to four hundred feet; and 
at various places on the road to Big Salt Lick uncemented 
gravel, which is unquestionably of glacial origin, caps the 
tops of the hills at about the same height. It is not unlikely, 
therefore, that much of the outflow from around the dam 
was in the immediate vicinity of the ice-front. 

Professor E. W. Claypole, in an article * read before the 
Geological Society of Edinburgh and published in their 
“Transactions,” has given a very vivid description of the 
scenes connected with the final breaking away of the ice-bar- 
rier at Cincinnati. He estimates that the body of water held 
in check by this dam occupied twenty thousand square miles, 
and that during the summer months, when the ice was most 
rapidly melting away, it was supplied with water at a rate 
that would be equivalent to a rainfall of one hundred and 
sixty feet in a year! This conclusion he arrives at by esti- 
mating that ten feet of ice would annually melt from the 


* “The Lake Age in Ohio,” “ Transactions of the Geological Society of Edin- 
burgh,” 1887 


GLACIAL DAMS, LAKES, AND WATERFALLS. .387 


portion of the State which was glaciated, and which is about 
twice the extent of the unglaciated portion. Ten feet over 
the glaciated portion is equal to twenty feet of water over 
the unglaciated. To this must be added an equal amount 
from the area farther back whose drainage was then into the 
upper Ohio. This makes forty feet per year of water so con- 
tributed to this lake-basin. Furthermore, this supply would 
all be furnished in the six months of warm weather, and to 
a large degree in the daytime, which gives the rate above 
mentioned. 

The breaking away of the barrier to such a body of water 
is no simple affair. As this writer remarks: 


The Ohio of to-day in flood is a terrible danger to the val- 
ley, but the Ohio then must have been a much more formidable 
river to the dwellers on its banks. The muddy waters rolled 
along, fed by innumerable rills of glacier-milk, and often 
charged with ice and stones. The first warm days of spring 
were the harbinger of the coming flood, which grew swifter 
and deeper as summer came, and only subsided as the falling 
temperature of autumn again locked up with frost the glacier 
fountains. . . . The ancient Ohio River system was in its 
higher part a multitude of glacial torrents rushing off the ice- 
sheet, carrying all before them, waxing strong beneath the ris- 
ing sun, till in the afternoon the roar of the waters and their 
stony burden reached its maximum, and, as the sun slowly 
sank, again diminished, and gradually died away during the 
night, reaching its minimum at sunrise... . 

But, with the steady amelioration of the climate, more vio- 
lent and sudden floods ensued. The increasing heat of sum- 
mer compelled the retreat of the ice from the Kentucky shore, 
where Covington and Newport now lie, and so lowered its sur- 
face that it fell below the previous outflow-point. The waters 
then took their course over the dam, instead of passing, as 
formerly, up the Licking and down the Kentucky River Val- 
leys. The spectacle of a great ice-cascade, or of long ice-rapids, 
was then exhibited at Cincinnati. This cataract, or these rap- 
ids, must have been several hundred feet high. Down these 
cliffs or this slope the water dashed, meltirg its own channel, 


CUYAHOGA LAKE. 


Area about 55 Sqr. Miles, 
Scale, 3 miles to 1 inch. 


Summit IL. 
396 ft.abdy 
L. Eric 


Ql Tuscarary, 


pL. Cuyahoga 


La mane S 


aoe 5 
Ql 


La 


Struthers § Co., Engr’s,|\N. ¥. 


Fic. 112a.—Map illustrating a stage in the recession of the ice in Ohio. For a section of 
the deposit in the bed of this lakelet, see page274._ The gravel deposits formed at this 
stage along the-outlet into the Tuscarawas River are very clearly marked (Claypole). 


(‘‘ Transactions of the Edinburgh Geological Society.’’) 


. 
] 
; 


GLACIAL DAMS, LAKES, AND WATERFALLS. 389 


and breaking up the foundations of its own dam. With the 
depression of the dam the level of the lake also fell. Possibly 
the change was gradual, and the dam and the lake went gently 
down together. Possibly, but not probably, this was the case. 
Far more likely is it that the melting was rapid, and that it 
sapped the strength of the dam faster than it lowered the 
water. This will be more probabie if we consider the immense 
area to be drained. The catastrophe was then inevitable—the 
dam broke, and all the accumulated water of Lake Ohio was 
poured through the gap. Days or even weeks must have 
passed before it was all gone; but at last its bed was dry. The 
upper Ohio Valley was free from water, and Lake Ohio had 
passed away... . 

But the whole tale is not yet told. Not once only did 
these tremendous floods occur. In the ensuing winter the 
dam was repaired by the advancing ice, relieved from the melt- 
ing effects of the sun and of the floods. Year after year was 
this conflict repeated. How often we can not tell. But there 
came at last asummer when the Cincinnati dam was broken 
for the last time ; when the winter with its snow and ice failed 
to renew it, when the channel remained permanently clear, and 
Lake Ohio had disappeared: forever from the geography of 
North America... . 

How many years or ages this conflict between the lake and 
the dam continued it is quite impossible to say, but the quan- 
tity of wreckage found in the valley of the lower Ohio, and 
even in that of the Mississippi, below their point of junction, 
is sufficient to convince us that it was no short time. ‘‘ The 
age of Great Floods” formed a striking episode in the story of 
the ‘‘ Retreat of the Ice.” Long afterward must the valley 
have borne the marks of these disastrous torrents, far surpass- 
ing in intensity anything now known on the earth. The great 
flood of 1885, when the ice-laden water slowly rose seventy-three 
feet above low-water mark, will long be remembered by Cincin- 
nati and her inhabitants. But that flood, terrible as it was, 
sinks into insignificance beside the furious torrent caused by the 
sudden, even though partial, breach of an ice-dam hundreds of 
feet in height, and the discharge of a body of water held behind 
it, and forming a lake of twenty thousand square miles in extent. 


390 | THE ICE AGE IN NORTH AMERICA. 


To the human dwellers in the Ohio Valley—for we have 
reason to believe that the valley was in that day tenanted by 
man—these floods must have proved disastrous in the extreme. 
It is scarcely likely that they were often forecast. The whole 
population of the bottom lands must have been repeatedly 
swept away; and it is far from being unlikely that in these 
and other similar catastrophes in different parts of the world, 


Fia. 113.—Section of the lake ridges near Sandusky, Ohio. 


which characterized certain stages in the Glacial era, will be 
found the far-off basis on which rest those traditions of a flood 
that are found among almost all savage nations, especially in 
the north temperate zone. 


‘ 
7 
i 


GLACIAL DAMS, LAKES AND WATERFALLS. 391 


Since the above account was written there has been a 
very animated discussion of the theory, the result of which 
has been to confirm the general view here maintained, while 
modifying some of the subsidiary points. Professor T. C. 
Chamberlin early expressed his disbelief in the dam, and 
after traversing the Monongahela Valley from Morgantown 
to Pittsburg expressed his belief that the clay deposits there, 
which Professor I. C. White had regarded as practically on 
a water level for a distance of more than 100 miles, were flood 
plain deposits of a flowing stream descending with the gradient 
of the valley. As Professor Chamberlin had taken pains to 
express this view in his introduction to my Bulletin published 
by the U. 8. Geological Survey (No. 54), it became necessary 
for a committee of the American Association for the Advance- 
ment of Science to go over the ground with Professor White. 
The result was that everyone was convinced of the correctness 
of the facts as stated in my original publication.* It appeared 
that as Professor Chamberlin did not find Professor White 
at home, he failed to see the facts which Professor White had 
recorded. That an ice dam existed which ponded up the water 
in the Monongahela to a height of more than 1,000 feet above 
the sea is established beyond all controversy. But its immedi- 
ate connection with the Cincinnati ice dam is now thrown 
into the background by the broader considerations already 
brought to light in areas the formation of the present 
Ohio River. 

The following facts detailed ina paper read, by Professor 
White, before the Geological Society of America,f at the Buf- 
falo meeting in 1896 are as interesting as they are conclusive 
in establishing the existence of an ice-dam in the Upper Ohio 
Valley. Atthreedifferent points the divide between the Up- 
per Monongahela basin and the valley of the Ohio, is cut by 


> NR heh of the Geological Society of America,’’ vol xiv (1902), 


ong Published in ‘‘Am. Geol.,’’ vol. xviii, Dec. 1896, “Origin of the 
High Terrace Deposits of the Monongahela River.’ 


392 THE ICE AGE IN NORTH AMERICA. 


abandoned water weirs at an elevation of approximately 1,100 
feet above tide. These are just such channels or “cols” as 
would be cut by the escaping water impounded by an ice-dam 
which obstructed the northerly drainage of the Monongahela. 
The terrace deposits of clay, quicksand, sand and gravel, bor- 
dering the river valley for more than 100 miles below Weston 
in West Virginia, range from 1,020 to 1,068 feet above tide, 
while that at Pittsburg is 990 feet above tide. The present 
river falls 290 feet between Weston and Pittsburg, while 
the terrace falls only forty feet in 200 miles at Pittsburg, and 
eight feet at Geneva, 117 miles below Weston. In tabular 
form the facts are as follows. 


PRESENT RIVER TOP OF DEPOSITS 


MILES a A.T. 

0 Weston 990 _ 1,030 
40 Clarksburg 916 1,020 
75 Fairmont 851 1,067 

101 Morgantown 787 1,038 
117 Geneva (2 1,022 
206 Pittsburg 700 990 


These terraces are specially prominent wherever a tributary 
comes into the main valley to form a delta at the level of 
the impounded water. Frequently the clay topping of the 
terrace is more than sixty feet thick, furnishing material for 
numerous pottery establishments. 

The following plants were identified by Dr. F. H. Knowl- 
ton, as occurring in these clay deposits. 1. Equisetum arvense 
L.; 2. Cyperus sp.; 3. Potamogeton robbinsi Oakes; 4. Liqui- 
dambar_ styracifolia L; 5. Platanus occidentalis L (sycamore) ; 
6. Ulmus racemosa Thomas (the white elm); 7. Quercus 
falcata Michigan; 8. Betula nigra L. (black birch); 9. Fagus 
ferruginea Ait (beech) ; 10. Castanea pumila Mill (chinquapin). 
All of these are living species, and most of them are still 
found in the vicinity. But special interest attaches to Pota- 
mogeton robbinsit, of which a great number of fragments of 


GLACIAL DAMS, LAKES AND WATERFALLS. 393 


stems and leaves were found. Its present distribution is 
from New Brunswick to New Jersey, north of Lake Superior 
and northward. The occurrence of this species in these beds 
is, as Professor White remarks, of special interest, since it 
practically demonstrates that there was during glacial times 
a movement of water from the edge of the ice near Beaver, 
Pennsylvania, southward along the Monongahela Valley, 
through the escape weirs just described, which brought with 
it this northern plant. 

Since as already shown the preglacial drainage of both the 
upper and the middle portions of the Ohio basin was to the 
north, it follows that vast sheets of water were ponded up in 
front of the advancing ice-sheet from the moment that those 
northern outlets were closed. One of the most prominent of 
these would be that occupying the basin drained in preglacial 
times by the Monongahela and Lower Allegheny rivers, which 
originally flowed off through Beaver Creek and the Grand 
River valleys into Lake Erie a little east of Ashtabula. This 
temporary lake would have its level regulated by the height 
of the col already referred to at New Martinsville, a little 
below Wheeling, West Virginia. It was in this glacial lake 
that the deep still water clay deposits described along the 
Middle Monongahela accumulated. But after a compara- 
tively short period the col at New Martinsville was worn down 
so that a permanent line of drainage was opened in that direc- 
tion and Lake White, as we may be permitted to name it, 
no longer existed in the Monongahela Valley. 

But as the ice-sheet continued to advance through central 
and southern Ohio the other lines of northerly drainage were 
obstructed and other temporary lakes formed which continued 
until the col, in the Muskingum above Zanesville, and that in 
the Ohio below the mouth of the Scioto were eroded suffi- 
ciently to permanently open present lines of drainage. Then, 
finally, when the ice reached the junction of Mill Creek Valley 
and the Great Miami at Hamilton, O., the whole drainage 


394 THE ICE AGE IN NORTH AMERICA. 


which had been flowing in that direction was so obstructed 
that it was turned over the col which existed a little below 
Cincinnati, and the permanent channel was opened which 
is now followed by the Ohio River. During this period of 
erosion there was a temporary lake formed above Cincinnati, 
but of comparatively short duration, for the immense flow 
of water from the whole upper basin of the Ohio would work 
with great rapidity to cut down the col below the city. 

After this there followed in immediate succession, the 
Cincinnati ice-dam proper, of which an account has been 
given. For a distance of fifty miles the ice advanced into 
Kentucky to heights of land fully 500 feet above the present 
level of the river, and must have obstructed the drainage up ~ 
to that level. This was doubtless of comparatively short 
duration, but while it continued it would set the water in 
the whole valley above to that height, which would submerge 
Pittsburg to a depth of 300 feet, and reach far up both the 
Monongahela and the Allegheny rivers. The shortness of 
its duration, however, makes it difficult to distinguish its 
deposits from those which had been made during the con- 
tinuance of the earlier ice-dams. While admitting there- 
fore, that the ‘Cincinnati ice-dam”’ was at first somewhat 
overworked in accounting for the deposits in the Upper Ohio 
Valley, it is by no means ruled out of the problem. TheCin- 
cinnati ice-dam still remains a fact with which all students 
of the region are compelled to reckon. 

As already intimated, however, the existence of the Cin- 
cinnati dam would necessitate an overflow either into the 
Kentucky River or around the margin of the ice, and such a 
channel, if it ever existed, should be easily discovered. 
But though I have diligently searched for it, it has so far 
eluded observation. This has inclined me to account for 
the Kentucky deposits as results of annual ice gorges, dur- 
ing the climax of the period, in the narrow channel below the 
city. But even so the phenomenon is none the less impres- 
sive, and would involve the flooding of the upper Ohio and 
its tributaries to the extent stated. 


GLACIAL DAMS, LAKES, AND WATERFALLS. | 395 


On coming to the region of the Great Lakes, the influence 
of ice-barriers is very conspicuous. South of Lake Erie there 
is an ascending series of what are called lake ridges. These 
are composed of sand and gravel, and consist largely of 
local material, and seem to maintain throughout their entire 
length a definite level with reference to the lake, though 
accurate measurements have not been made over the whole 
field. The approximation, however, is_ sufficiently per- 
fect to permit us to speak of them as maintaining a uniform 
level. These ridges can be traced for scores of miles in a 
continuous line, and in the early settlement of the country 
were largely utilized for roads. In Lorain county, Ohio, 
an ascending series of four ridges can be distinguished at 
different levels above the lake.* The highest is from 200 
to 220 feet above it; the next is approximately 150 to 
160 feet; the next lower is from 100 to 118 feet; and the 
next lower less than 100 feet, while some appear on the 
islands near Sandusky which are not over 70 feet above the 
water-level. Eastward from Buffalo portions of this series 
have been traced, according to Gilbert, until they disappear 
against the highlands near Alden, on the Erie Railroad. 

Lake Ontario is likewise bordered by similar ridges upon 
its southern and eastern sides, but the investigations in that 
region are not yet complete enough to be altogether satisfac- 
tory. From what has already been done it is evident that 
they do not maintain so nearly a uniform level as on the 
shores of Lake Erie. Mr. G. K. Gilbert, of the United States 
Geological Survey, informs me that, from the vicinity of 
Oneida Lake toward the northeast, the ridges rise rapidly 
with reference to the lake-level, and that to a less extent 
they rise in a westerly direction, showing that if they were 
water-deposits, there has been considerable oscillation of the 
land both northeast and southwest of an axis following the 
line of the Mohawk Valley. 

‘That the ridges on Lake Erie mark toupee ary shore-lines 


* “ Geological Survey of Ohio,” vol. ii, p. 207. 


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GLACIAL DAMS, LAKES, AND WATERFALLS. 397 


of the lakes can not well be doubted, for they are not related 
to any great natural lines of drainage, but follow the wind- 
ings ofa definite level, receding from the lake wherever 
there is a transverse valley, and forming in some cases parallel 
embankments on either side of such valley, running inland 
as far as to the general level of the series, and then return- 
ing on itself upon the other side, to strike off again par- 
allel with the shore at the same level. Their relation to the 
lake is also shown by the local character of the material. It is 
usually such as would wash up on the shore out of the roek in 
place. In the sandstone region the ridges are largely made 
up of sand, mingled with fragments from the general glacial 
deposit. Over the regions of outcropping shales the ridges 
are composed largely of the harder nodules which have suc- 
cessfully resisted the attrition of the waves. Other evidences 
that they are shore-deposits are their stratification, the rela- 
tive steepness of their sides toward the lake, and the frequent 
occurrence of fragments of wood buried at greater or less 
depths on their outer margin. 

It need not be said that there has been much speculation 
concerning the cause which maintained the waters of the 
lakes at the levels indicated by these ridges, and permitted 
them to fall from the level of one to that of another in suc- 
cessive stages, so suddenly as they seem to have done; for, 
from the absence of intermediate deposits, it is evident that 
the formation of one ridge had no sooner been completed, 
than the one at the next lower level began to form. In the 
earlier stages of glacial investigation, before the full power 
and flexibility of glacial ice were appreciated, and before 
the exact course of the southern boundary of the ice-sheet 
was known, the elevation of the water to produce these 
ridges was supposed to have resulted either from a general 
subsidence of the whole region to the ocean-level, or from 
the elevation of a rocky barrier across the outlet. Both 
these theories were attended with insuperable difficu!ties. 
In the first place, there is no such amount of collateral evi- 
dence to support the theory of general subsidence as there 


398 THE ICH AGE IN NORTH AMERICA. 


should be if it really had occurred. The subsidence of the 
lake region to such an extent would have left countless 
other marks over a wide extent of country ; but such marks 
are not to be found. Especially is there an absence of 
evidences of marine life. The cause was evidently more 
local than that of a general subsidence. The theory of the 
elevation of a rocky barrier would also seem to be ruled out 
of the field by the fact that no other direct evidence can be 
found of such recent local disturbances. Such facts as we 
have point to a subsedence at the east rather than to an eleva- 
tion. 


But a glance at the course of the terminal moraine, and 


at the relation of the outlets of these lakes to the great ice- 
movements of the Glacial period, brings to view a most 
likely cause for this former enlargement and increase in 
height of the surface of the lower lakes. It will be no- 
ticed that the glacial front near New York city was about 
one hundred miles farther south than it was in the vicinity 
of Buffalo. Hence the natural outlet to the Great Lakes 
through the Mohawk Valley would not have been opened 


until the ice-front over New England and eastern New York ~ 


had retreated to the north well-nigh one hundred and fifty 
miles. A similar amount of retreat of the ice-front from 
its farthest extension in Cattaraugus county, in New York, 
would have carried it back thirty miles to the north of Lake 
Ontario, while a similar amount of retreat from eastern Ohio 
would have left nearly all the present bed of Lake Erie free 
from glacial ice. With little doubt, therefore, we have, in 
the lake ridges of Upper Canada, New York, and Ohio, evi- 
dence of the existence of an ice-barrier which continued to 
fill the valley of the Mohawk, and choke up the outlet through 
the St. Lawrence, long after the glacial front farther to the 
west had withdrawn itself to Canada soil. A study of these 
ridges may yet shed important light upon the length of time 
during which this ice-barrier continued across the valley of 
the Mohawk. | 


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Fic. 117—Nipissing Great Lakes and Champlain Sea. Numerous isobases give altitude 


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THE GLACIAL LAKE AGASSIZ 
By WaRREN UpnHam, D.Sc., 


Sr. Paut, MINN. 


As soon as the departing ice-sheet, which had enveloped 
the northern United States and British America during the 
glacial period, in its final melting off the land from south to 
north, receded beyond the water-shed dividing the basin of 
the Minnesota River from that of the Red River of the North, 
a lake, fed by the glacial melting, stood at the foot of the ice- 
fields, and extended northward as they withdrew along the 
valleys of the Red River to Lake Winnipeg, filling this valley 
and its branches to the heights of the lowest points over 
which an outlet could be found. Until the ice-barrier was 
melted away on the area now crossed by the Nelson River, 
thereby gradually draining this glacial lake, its outlet was 
along the present course of the Minnesota River. At first 
its overflow was upon the nearly level undulating surface 
of the drift, 1,050 to 1,125 feet above the sea, at the west 
side of Traverse and Big Stone counties, Minnesota; but in 
process of time this cut a channel there, called Brown’s 
Valley, 100 to 150 feet deep and about a mile wide, the highest 
point of which, on the present water divide between the Missis- 
sippi and Nelson river basins, is 975 feet above the sea-level. 
From this outlet the Red River valley plain extends 315 miles 
north to Lake Winnipeg, which is 710 feet above the sea. 
Along this entire distance there is a very uniform continuous 
descent of a little less than one foot per mile. 

Thefarmers and other residents of this fertile plain are 
well aware that they live on the area once occupied by a great 
lake; for its beaches, having the form of smoothly rounded 
ridges of gravel and sand, a few feet high, with a width of 
several rods, are observable extending almost horizontally 
long distances upon each of the slopes which rise east and west 
of the valley plain. Hundreds of farmers have located their 


402 THE ICE AGE IN NORTH AMERICA. 


buildings on these beach ridges as the most dry and sightly 
spotson their lands, affording opportunity for perfectly drained 
cellars even in the wettest seasons, and also yielding to wells, 
dug through this sand and gravel, better water than is usually 
obtainable in wells on the adjacent clay areas. While each 
of these farmers, in fact every one living in the Red River 
Valley, recognizes that it is an old lake bed, few probably 
know that it has become for this reason a district of special 
interest to geologists, who have traced and mapped its upper 
shore along a distance of about 800 miles. 

Numerous explorers of this region, from Long and Keat- 
ing in 1823, to Gen. G. K. Warren in 1868 and Prof. N. H. 
Winchell in 1872, recognized the lacustrine features of the 
valley; and the last named geologist first gave what has been 
generally accepted as the true explanation of the existence of 
the lake, namely, that it was produced in the closing stage 
of the glacial period by the dam of the continental ice-sheet 
at the time of its melting away. As the border of the ice-sheet 
retreated northward along the Red River Valley, drainage 
from that area could not flow as now freely to the north 
through Lake Winnipeg and into the ocean at Hudson Bay, 
but was turned by the ice-barrier to flow south across the 
lowest place on the water-shed, dividing this basin from that of 
the Mississippi. This lowest point is found, as before noted, 
at Brown’s Valley on the western boundary of Minnesota, 
where an ancient water-course, about 125 feet deep and one 
mile to one and a half miles wide, extends from Lake Traverse, 
at the head of the Bois des Sioux, a tributary of the Red River, 
to Big Stone Lake, through which the head stream of the Min- 
nesota River passes in its course to the Mississippi and the 
Gulf of Mexico. 

Detailed exploration of the shore lines and area of this 
lake was begun by the present writer for the Minnesota 
Geological Survey in the years 1879 to 1881, under the direc- 
tion of Professor N. H. Winchell, the State geologist. In 


THE GLACIAL LAKE AGASSIZ. 403 


subsequent years I was employed also in tracing the old lake 
shores through North Dakota for the United States Geological 
Survey, and in Southern Manitoba, to the distance of 100 
miles north from the international boundary te Riding 
Mountain, for the Geological Survey of Canada. For the 
last named survey, Mr. J. B. Tyrrell extended the exploration 
of the lake shore lines more or less completely for 200 miles 
farther north along the Riding and Duck mountains and the 
Porcupine and Pasquia hills, west of Lakes Manitoba and 
Winnipegosis, to the Saskatchewan River. 

This glacial lake was named by me in the eighth annual 
report of the Minnesota Geological Survey, for the year 
1879, in honor of Louis Agassiz, the first prominent advocate 
of the theory of the formation of the drift by land ice; and the 
outflowing river, whose channel is now occupied by Lakes 
Traverse and Big Stone and Brown’s Valley, was named also 
by me, in a paper read before the American Association for the 
Advancement of Science at its Minneapolis meeting in 
1883, the River Warren, in commemoration of General War- 
ren’s admirable work in the United States Engineering Corps, 
in publishing maps and reports of the Minnesota and Missis- 
sippi River surveys. 

Descriptions of Lake Agassiz and the River Warren are 
somewhat fully given in the eighth and eleventh annual reports 
of the Minnesota Geological Survey, and in the first, second, 
and fourth volumes of its final report. Three other special re- 
ports of my explorations of Lake Agassiz were published; the 
first in 1887, as Bulletin No. 39, of 84 pages, with a map, by 
the Geological Survey of the United States; the second in 
1890, by that of Canada, in its Annual Report, New Series, 
vol. iv, for 1888-89, forming Part E, 156 pages, with maps and 
sections; and last, this subject was most fully issued by the 
U. S. Geological Survey, as its Monograph XXV, 1895, a 
quarto volume of 658 pages and 38 plates (maps, views, and 
sections). 


404 THE ICE AGE IN NORTH AMERICA. 


Several successive levels of the ancient lake are recorded by 
distinct and approximately parallel beaches, due to the gradual 
lowering of the outlet by the erosion of the channel at Brown’s 
Valley, and these are named principally from stations on the 
Breckenridge and Wahpeton line of the Great Northern 
Railway, in their descending order, the Herman, Norcross, 
Tintah, Campbell, and McCauleyville beaches, because they 
pass through or near these stations and towns. 

The highest or Herman beach is traced in Minnesota from 

the northern end of Lake Traverse eastward to Herman, and 
thence northward, passing a few miles east of Barnesville, 
through Muskoda, on the Northern Pacific Railway, and 
around the west and north sides of Maple Lake, which lies 
about twenty miles east—southeast of Crookston, beyond 
which it goes eastward to the south side of Red and Rainy 
lakes. In North Dakota the Herman shore lies about four 
miles west of Wheatland, on the Northern Pacific Railway, and 
the same distance west of Larimore, on the Pacific line of the 
Great Northern Railway. On the international boundary, in 
passing from North Dakota into Manitoba, this shore coin- 
cides with the escarpment or front of the Pembina Mountain 
plateau, and beyond passes northwest to Brandon on the 
Assiniboine River, and thence northeast to the Riding 
mountain. 

Leveling along this highest beach shows that Lake Agassiz, 
in its earliest and highest stage, was nearly 200 feet deep above 
Moorhead and Fargo; a little more than 300 feet deep above 
Grand Forks and Crookston; about 450 feet above Pembina, 
St. Vincent, and Emerson; more than 500 feet above the 
city of Winnipeg; and about 500 and 600 feet, respectively, 
above Lakes Manitoba and Winnipeg. ‘The length of Lake 
Agassiz is estimated to have been nearly 700 miles, and its 
area not less than 110,000 square miles, exceeding the com- 
bined areas of the five great lakes tributary to the St. Lawrence. 


THE GLACIAL LAKE AGASSIZ. 405 


When the ice-barrier was so far melted back as to give out- 
lets northeastward lower than the River Warren, other 
beaches marking these lower levels of the glacial lake were 
formed; and finally, by the full departure of the ice, Lake 
Agassiz was drained away to its present representative, Lake 
Winnipeg. 

The rate of the northward ascent of the originally level 
highest beach, within the area of my leveling, varied from 
about six inches per mile near its southern end to about one 
foot per mile along the greater part of its extent to southern 
Manitoba. On the east side of the Red River Valley the old 
shores are higher than on its west side, the rate of ascent from 
west to east being about half as much as from south to north. 
The direction of maximum ascent of the planes of the former 
lake levels is therefore toward the north-northeast. Farther 
north several beaches of the seriesmapped by Tyrrell along 
the bases of the Riding and Duck mountains have a northward 
rise of two or three feet per mile. The changes of level were 
in progress and were nearly completed during the existence 
of Lake Agassiz, as is shown by the gradual diminution in 
the northward ascent of the successive lower beaches, until 
the latest and lowest differs only slightly from perfect hori- 
zontality. ; 

Gravitation of Lake Agassiz toward the ice-sheet accounts 
for a small part of the present inclination of the beaches. 
Changes in the temperature of the earth’s crust due to the 
glacial period and its termination produced a still smaller 
effect, but this tended to give the opposite slope, or a descent 
toward the north. Upward movement of this great land area, 
resulting from its being unburdened by the departure of the 
ice-sheet, was the chief element in the causes of the differential 
changes in the height of this basin. Flow of the plastic inner 
part of the earth’s mass, restoring its equilibrium or isostasy, 
uplifted first the southern half of the area of Lake Agassiz, 
from Lake Traverse to Gladstone in Manitoba; nextit raised 


406 THE ICE AGE IN NORTH AMERICA. 


the northern half of the lake area, while the region at the south 
was almost at rest; and finally, during the recent epoch, after 
the whole basin of Lake Agassiz was passed by this wave like 
permanent uplift, it has been elevating the basin of Hudson 
Bay, where the movement appears to be still in progress. 
Pleistocene oscillations of the land in many other parts of 
the world have been independent of glaciation, or these have 
been combined with movements due to the accumulation of 
ice-sheets and to their removal; but the uplifting of the basins 
of Lake Agassiz and Hudson Bay is apparently attributable 
wholly to the departure of the ice-sheet. 

The entire duration of Lake Agassiz, estimated from the 
amount of its wave action in erosion and inthe accumulation 
of beach gravel and sand, appears to have been only about 
1,000 years; and the time of its existence and of the end of the 
ice age is thought, from the rate of recession of the Falls of 
St. Anthony, cutting the post-glacial gorge of the Mississippi 
River from Fort Snelling to Minneapolis, to have been some- 
where between 6,000 and 10,000 years ago. 


CHAPTER XVI. 
THE LOESS. 


TuHE deposit called doess received its name in Germany, 
where it was first described. But its most remarkable devel- 
opments are in China and in America. The formation is 
one of great interest in every respect. It furnishes the most 
fruitful soil in the world, and is extensively used for the ex- 
eavation of houses in China and in some parts of America. 
At the same time it presents the scientific observer with a 
most attractive but puzzling problem. Professor Pumpelly, 
who has seen it in all parts of the world, gives the following 
lucid description of the deposit : 


This remarkable formation covers several hundred thousand 
square miles in northern China, and larger areas in the rest of 
Asia. It forms the soil also over an immense area in the west- 
ern United States. Its thickness varies in China up to two 
thousand feet, and to one hundred and fifty and two hundred 
feet in Europe and America. 

Loess is a calcareous loam. It is easily crushed in the hand 
to an almost impalpable powder, and yet its consistency is such 
that it will support itself for many years in vertical cliffs two 
hundred feet high. A close examination shows that it is filled 
with tubular pores branching downward like rootlets, and that 
these tubes are lined with carbonate of lime. It is to these 
that it owes its consistency and its vertical internal structure. 
It is wholly unstratified, and often where erosion has cut into 
it, whether one foot or one hundred yards, the walls are ab- 
solutely vertical. Its vertical internal structure causes it to 


break off in any vertical plane, but in no other. Hence, when 
26 


408 THE ICE AGE IN NORTH AMERICA. 


a cliff is undermined, the loess breaks off in immense vertical 
plates leaving again a perpendicular wall. 

It is divided into beds varying in thickness from one foot 
to two or three hundred, which thin out to nothing at the bor- 
ders and are separated by parting planes. These planes are 
marked by angular débris near the mountains, and by elon- 
gated upright calcareous concretions elsewhere. 

This remarkable combination of softness with great strength 
and stability of exposed surfaces is of inestimable value in a 
woodless country. In Asia, thousands of villages are excavated 
in a most systematic manner at the base of cliffs of loess. 
Doors and windows pierced through the natural front give 
light and air to suites of rooms which are separated by natural 
walls, and plastered with a cement made from the loess concre- 
tions. These are the comfortable dwellings of many millions 
of Chinese farmers, and correspond to the ruder dug-outs of 
Nebraska. 

‘To the same qualities is due the fact that the loess districts 
of China are exceedingly fertile plains, in each of which a rap- 
idly progressing erosion has excavated the most labyrinthine 
valley systems, in which all the members, down to the smallest 
tributaries, are sunk with vertical walls to depths of from one 
hundred to several hundred feet. Even the wagon-roads be- 
come in time depressed to a depth of fifty feet and more by the 
removal of the dust by wind. 

There is one more peculiarity of the loess: it not only is 
wholly unstratified, but it contains the remains of only land- 
animals and especially of land-snails. Alexander Braun ex- 
amined 211,968 specimens of shells from the loess of the Rhine 
between Basle and Bonn, and found that all were land-snails 
except only thirty-three individuals, consisting of Limnea, 
Planorbis, and Vitrina, which came from three isolated points 
in the valley of the Rhine and Neckar. 


Baron Richthofen, after prolonged study of the loess of 
China, propounded the theory that it was a wind-deposit, 
consisting of material which had resulted from the slow dis- 
integration of the rocks in the arid regions of central Asia, 
from which the westerly winds have been continually blow- 


THE LOESS. 409 


ing for an untold period. As applicable to China, Richt- 
hofen’s theory is perhaps adequate. Mr. Pumpelly is also 
inclined to accept the theory as applicable to Ameriea, re- 
marking that— 

No one can realize the capacity of wind as a transporter of 
fine material who has not lived through at least one great storm 
on a desert. In such a simoon the atmosphere is filled with a 
driving mass of dust and sand which hides the country under 
a mantle of impenetrable darkness, and penetrates every fabric ; 
it often destroys life by suffocation, and leaves in places a deposit 
several feet deep. 

The prevailing westerly wind, carrying sand, carves and pol- 
ishes the rocky crest of the Sierra Nevada, and, as Mr. King 
tells me, has formed long wind-stream deltas—if I may coin 
the term—in the form of lofty sand ranges stretching from 
each pass eastward, far out on the desert. 

The often cited instances of far-driven volcanic ashes show 
the ability of the wind to carry comparatively coarse dust 
through distances of several hundred miles, but it does not 
seem improbable that the finer particles may remain suspended 
while the wind makes a complete circuit of the globe. I wit- 
nessed on March 31st and April 1st, in 1863, a dust-fog at 
Nagasaki which lasted two days, and left only a just percepti- 
ble film of dust, observable only on the white, newly painted 
deck of a yacht. A similar fall occurred simultaneously at 
Shanghai, and both were contemporaneous with a terrific dust- 
storm which during two days shrouded the country about 
Tientsin in deep darkness. 

I am indebted again to Mr. Clarence King for the state- 
ment that dust-fogs occur on the coast of California with the 
prevailing west wind; and this may be, as he suggests, the 
finest residuum of the loess-dust of an Asiatic dust-storm.* 


Concerning the power of wind to transport dust, many 
other striking illustrations have been noted. Showers of red- 
dish dust occasionally fall upon ships far out at sea. Darwin 
describes one such storm encountered by him near the Cape 


* “ American Journal of Science,” vol. exvii, 1879, pp. 138, 134, 139. 


410 THE ICE AGE IN NORTH AMERICA. 


Verds, which was estimated to be sixteen hundred miles 
broad. A similar shower which passed over the southern 
part of France in 1846 is estimated by Ehrenberg to have 
deposited nearly a million pounds of dust. On examination 
he found that about one eighth of it consisted of microscopic 
organisms, many of which belonged in South America, thus 
showing that the wind had blown the dust across the Atlan- 
tic. In 1835 volcanic dust was blown from Guatemala to 
Jamaica, a distance of eight hundred miles. 

The main difficulty of applying the wind theory to account 
for the loess of the Mississippi Valley and of Europe lies in 
its definite relation to water-levels. For example, in the 
Rhine Valley the loess rests in places upon elevations of 
eight hundred feet above the river, but does not occur at 
higher levels. This would clearly indicate that it is a water- 
deposit. The problem has been to conceive how the water 
could be maintained at that level in the valley of the Rhine; 
and the theory has been put forth, and ably defended by 
Geikie and others, that the Rhine and other rivers emptying 
into the North Sea were obstructed at their mouths by the 
Scandinavian glaciers, and so the water was ponded back 
toward the Alps to the level at which the loess ceases. 

The absence of fossils of aqueous origin in the loess may 
be accounted for in two ways: 1. If the deposit took place, 
as was supposed, in temporary glacial lakes, there may have 
been no species existing in them to have left their remains. 
This would be likely to be the case for three reasons: (1) 
the lakes were of only temporary continuance ; (2) the tem- 
perature of the water must have been abnormally low; and 
(3) the superabundance of silt might interfere with animal 
life. 2. Professor Hilgard has suggested that the porosity 
of the loess, which favors the continual presence and percola- 
tion of water charged with acids throughout its mass, renders 
it almost certain that any inclosed fossils would have been 
rapidly dissolved. As to why this oxidizing and dissolving 
process should have selected fossils of aqueous origin, and 
made an exception in favor of those of terrestrial animals, 


THE LOESS. 411 


Professor Hilgard explains that the terrestrial fossils are, as 
a matter of fact, found near the marginal portion of the loess, 
where the destructive processes are least. Whether, also, 
there may not be a difference between the destruetibility of 
land- and fresh-water shells is also a question. The occur- 
rence of nodules of lime throughout the mass points to such 
a work of solution and redistribution by water. In regard to 
the frequent occurrence of the bones of the larger land-ani- 
mals, Professor Hilgard remarks: “That the phosphatic 
bones should not have dissolved as easily as the mere carbon- 
ate shells is readily intelligible; and as regards their mode of 
occurrence in the loess of the lower Mississippi they are 


Fic. 119.—Stratification of the loess in a railway cut at Plattsmouth, Nebraska, at a depth 
of Sek Sed feet from the surface. (From pioeran furnished by Dr. A. L. 
Child, of Kansas City, Mo.) (Chamberlin.) (United States Geological Survey.) 

always very much scattered, many bones belonging to the 
same individual being rarely found together, but seeming to 
have drifted widely apart. It is not easy to see how the 
cumbrous bones of the mammoth could have been widely 
separated in a subaérial deposit.” * 


* “ American Journal of Science,” vol. exviii, 1879, p. 110. 


412 THE ICE AGE IN NORTH AMERICA. 


- It. is to President Chamberlin, again,* that we are in- 
debted for the most careful study of this problem in the Mis- 
sissippi Valley. According to him, the loess is limited pre- 
dominantly to the river valleys, and the belt is ordinarily not 
over forty miles in width. As a rule, also, it is thicker and 
slightly coarser in character near the banks of the great riy- 
ers, and there shows some signs of stratification. 

A comparison of loess with sand and clay reveals some 
interesting facts. The loess is intermediate in size and tine- 
ness. When the particles are suspended in water, the loess 
settles much more rapidly than clay—as much of the loess 
settling in four hours as of the clay in thirty-six hours. Out 
of 150,000 particles of loess examined under the microscope, 
146,000, or about rinety-seven per cent, were less than -005 
of a millimetre in diameter. A grain of sand one millimetre 
in diameter is considered fine. But this would make 200,000 
particles of loess of the size mentioned, and 100,000 particles 
of the fineness of a large part of true clay. The size of the 
largest particles of loess noted by President Chamberlin was 
about one tenth of a millimetre in size, and consisted of seales 
of mica. The loess of Vicksburg is a little finer than that of 
Kansas City, and both a little finer than that from the Rhine. 
The particles of loess were found to be angular and irregular. 
“Sharp corners and rough surfaces are the rule, and any ap- 
proach to regularity or smoothness is the exception.” In 
the vicinity of the great rivers the grains are coarser than at 
points removed from them. In chemical composition the 
difference between loess and true residual clays is not very 
striking ; but, as compared with glacial clays, occurring in the 
till, there is a marked difference in several respects. The gla- 
cial clays have far less amount of silica and alumina, and a far 
larger amount of calcic and magnesian oxides and of carbonic 
dioxides. The glacial clays are evidently the result largely 
of mechanical abrasion; but the loess would seem to consist 
in larger proportion of material resulting from chemical dis- 


* “Driftless Area of the Upper Mississippi Valley,” pp. 278-307. 


THE LOESS. 413 


integration. But the amount of kaolinized products is nearly 
four times as great in the residuary clays as in glacial clays or 
loess. } 

The altitude of the loess deposits in the Northwest is by 
no means uniform, and its variations present great theoretic 
difficulties. In the lower part of the Mississippi Valley it is 
limited to a height of about two hundred and fifty feet. In 
the upper Mississippi Valley, however, it rises to a height of 
seven hundred feet above the bed of the river. ‘To account 
for this, the first impulse would be to suppose a general de- 
pression of the northern region. But this theory is excluded 
by various irregularities in this region itself. For example, 
the loess rises much higher upon the west side of the upper 
Mississippi than upon the east side, especially in the vicinity 
of the driftless area of Wisconsin. 

To explain this it is necessary to resort to a rather com- 
plex theory. In part, perhaps, the peculiar distribution of 
loess is attributable to a period of general northerly depres- 
sion during the Glacial epoch. This apparent depression, 
however, was probably not caused wholly by an oscillation 
of the crust of the earth itself, since it is shown that it may 
be due in some degree. to the attraction of the ice which had 
accumulated to the north. Mr. R. S. Woodward, of the 
United States Geological Survey, has worked out the prob- 
lem of attraction and its influence in producing a higher level 
of water at the north, on the supposition that the ice-sheet 
was ten thousand feet thick, and covered an area to the north 
2,600 miles in diameter, and finds that the possible influence 
of such attraction might change the water-level at the ice- 
margin thirty-eight degrees from its center as much as 573 
feet. But the elevation of the loess attains a height in Iowa 
and Wisconsin of 1,285 feet. This theory of change of the 
water-level by glacial attraction, therefore, though not ade- 
quate, very evidently comes in for a part of the credit of pro- 
ducing the puzzling facts relating to the deposition of loess.* 


* “Driftless Area of the Upper Mississippi Valley,” pp. 291-301. 


414 THE ICE AGE IN NORTH AMERICA. 


A noticeable phenomenon west of the driftless area in 
Wisconsin and Iowa is that the loess is thickest near the east- 
ern margin of the ice-lobe which passed southward through 
central Iowa. The distance from the driftless area to the 
Missouri River, or the width of this lobe in the latitude of 
Milwaukee, is not far from three hundred and forty miles. 
It is urged that the presence of an ice-lobe over that region 
may have had influence in elevating the loess deposits. Since 
attraction varies inversely as the square of the distance, such 
a mass of ice near at hand would slightly raise the water along 
its margin. The objection to this is that the wider ice-lobe 
to the east did not produce corresponding influence. 

Among the more fruitful supplementary hypotheses 
brought in to aid in the solution of this part of the prob- 
lem is to be mentioned that of glacial dams similar to those 
already alluded to in Europe. In this country the principal 
field in which they may have existed is where it is most 
needed, namely, west of the Mississippi. An examination 
of our map will at once suggest that it is possible for much 
of the loess in northeastern Kansas and eastern Nebraska to 
have accumulated in temporary lakes formed by glacial dams 
across the mouth of the Kansas and Platte Rivers, or even of 
the Missouri itself. How far this cause may have operated 
remains yet to be determined. 

So complicated are the facts pertaining to the loess as 
they now appear, that it is not likely that, for some time to 
come, investigators will arrive at a perfect agreement con- 
cerning its manner of deposition. Those, however. who 
have most attentively studied glacial phenomena may be par- 
doned if they work the glacial hypothesis for all that it is 
worth. The existence of the vast body of ice which covered 
the glaciated area introduces a very complicated and efficient 
cause which it is exceedingly difficult to eliminate from the 
problem; and it is as allowable for the glacialist to take 
refuge in supposed ice-dams, where their existence is possible 
and can not be disproved, as for the ordinary geologist to sup- 
pose vast orographic changes. The study of the loess has 


THE LOESS. 415 


not come so much within my own field of observation as 
other glacial deposits have done. Still, in southern Indiana 
and Illinois, and in western Iowa and eastern Nebraska, I have 
been able to study many typical regions of this deposit ; and 
the more attention I have given to the subject, the more I 
have been led to magnify the agencies of the Ice period in 
producing the results both positive and negative. I have 
come, therefore, to set an increasingly high estimate upon 
the suggestions of Mr. Upham, made after he had concluded 
his survey of the terminal moraine in Minnesota, Lowa, and 
eastern Dakota : 


When the ice-sheet extended to the Coteau du Missouri, 
the Coteau des Prairies, and the Kettle-Moraine, the floods 
formed by its summer meltings were carried southward by the 
present avenues of drainage, the streams which occupied the 
areas between its great lobes in order from west to east being 
the Big Sioux, Mississippi, and Wisconsin Rivers. The vast 
glaciers which were gathered up on the Rocky Mountains, and 
the ice-fields which sloped downward to their termination at 
the coteaus and the moraine north and east in Minnesota and 
Wisconsin, supplied every summer immense floods laded 
with silt, sand, and gravel, that had been contained in the 
melting ice. Very extensive deposits of modified drift were 
thus spread along the course of the swollen Missouri and Mis- 
sissippi. The Orange sand and gravel, described by Professor 
E. W. Hilgard and others in the lower Mississippi Valley, ap- 
pear to have been deposited in this way, but during the earlier 
Glacial epoch, when an ice-sheet reached in Dakota beyond 
the Missouri River to a termination forty miles west and 
twenty miles southwest of Bismarck, into northeastern Kansas, 
half-way across the State of Missouri, and nearly to the Ohio 
River. 

In the closing stages of this epoch, and during the time 
succeeding, till the date of the terminal moraine of the coteaus, 
and especially at the final retreat of the ice-sheet of this later 
epoch, the deposition of the overlying, finely pulverized, are- 
naceous and calcareous silt, called the Bluff formation, or loess, 
took place. This covers considerable areas along the Mis- 


416 THE ICE AGE IN NORTH AMERICA. 


sissippi from southeastern Minnesota to its mouth; but its 
greatest thickness and extent are found in the basin of the 
Missouri River from southern Dakota to its junction with the 
Mississippi, and upon the region crossed by the Platte or 
Nebraska River, its longest tributary from the west, which 
takes its head-waters from a large district of the Rocky Mount- 
ains. The continuity of this formation from the borders of © 
the ice-sheet and the glaciers of the Rocky Mountains to the 
shores of the Gulf of Mexico, the absence from it of marine 
shells, and the presence of land- and fresh-water shells, indicate 
that its deposition was by slowly descending floods, uplifted 
upon the surface of this sediment which was being accumu- 
lated during every summer through a long epoch, in the same 
manner that alluvium is now spread upon the bottom-lands of 
our rivers at their times of overflow. The occurrence of the loess 
in Guthrie, Carroll, Sac, and Buena Vista counties * in Iowa, 
covering the region next west of the terminal moraine, with its 
surface fifty feet above these drift-hills and one hundred above 
the undulating area of till adjoining their east side, proves that 
during the time of deposition of this part of the loess the ice- 
sheet extended to this limit, and was a barrier preventing the 
waters by which this sediment was brought from flowing over 
the lower area of till that reaches thence east to the Des 
Moines River. When the ice-sheet retreated beyond the water- 
shed of the Missouri basin, the principal source of these floods 
and their sediment was removed, and the subsequent work of 
the rivers which cross the area of the loess has been to excavate 
their present valleys or channels, bounded by bluffs of this 
formation. t 


A supplementary hypothesis to account for the subsidence 
assumed by some is, that a bodily depression of the crust of 
the earth was produced by the weight of the glacier. If one 
is inclined at first thought to reject this cause as moperative 
because of its relative insignificance, he should reflect that 


* “The Ninth Annual Report of the Geological and Natural History Survey 
of Minnesota,” p. 307 e¢ seq. 
+ Ibid., pp. 337, 338. 


THE LOESS. 417 


the forces maintaining the present contour of the earth’s sur- 
face may be very evenly balanced, so that a slight addition 
at one point, and subtraction from another, might be the de- 
cisive influence in turning the scale. It is now pretty gener- 
ally believed that the long-continued and steady periods of 
subsidence involved in the formation of extensive sediment- 
ary rocks was due to the constant accumulation of the silt, 
out of which the rocks are made. This silt was relieving the 
continents of its weight, and adding to the weight along the 
whole line of deposition. During the Glacial period the 
transference of water from the ocean to accumulate as ice 
upon land removed an immense pressure from the ocean- 
beds, and added an equal amount of weight to the glaciated 
area. How much influence this may have had in depressing 
temporarily this area and its margin, we are unable to tell. 
But it is one of those unknown causes in the field which may 
be supposed to have accomplished something. 

Professor Alexander Winchell has, in a recent interesting 
paper, suggested a correlation between this pressure of the ice 
over the glaciated region and the enormous outflows of lava 
along the Rocky Mountains and the Cascade Range on the 
Pacific slope.* The lava-beds of that region are enormous in 
extent and are certainly of very recent date, and seem to 
have poured out from long fissures instead of craters. Under- 
neath these beds there are, in California and Oregon, glacial 
deposits ; and it is in these lava-covered glacial deposits of 
southern California that human remains are supposed by 
Whitney to have been found. Professor Winchell’s theory 
connecting those lava outflows with the depression produced 
by the ice of the Glacial period in the east would relieve 
the subject of considerable embarrassment arising from the 
chronological difficulties that have been suggested. To the 
superficial objection that pressure over the Mississippi Valley 
would not produce volcanic eruptions at so great a distance 


* “Some Effect of Pressure of a Continental Glacier,” in “The American 
Geologist,” March, 1888, pp. 139-148. 


418 THE ICE AGE IN NORTH AMERICA. 


as the Pacific coast, it is readily answered: “ The terrestrial 
globe in some of its behavior may be compared to an India- 
rubber ball filled with water. If indented by pressure in one 
place, there must be a protuberance equal in volume in 
another place. In a ball of uniform composition, the pro- 
tuberance would be spread over the entire surface beyond 
the region indented, and the effect in one particular spot 
might be insignificant. Should a small area of the caout- 
chouc be thinner than the rest, that part would be protruded 
to a greater extent than other parts of the surface. Should 
there be small holes or fissures through it, the water would 
escape and flow over the surface—that is, the protuberance 
resulting from local pressure would be chiefly on the outside 
of the shell. As we ordinarily conceive it, the water would 
be squeezed out like the juice of a squeezed orange.”* 
Another supplementary theory which has been invoked 
to account for the loess, is, that it has, in certain sections 
at least, been brought to the surface by the agency of earth- 
worms and other animals which burrow in the ground. The 
remarkable facts adduced by Mr. Darwin concerning the ac- 
tivity of these humble agents give respectability to the 
theory ; and, indeed, the power of these agencies can be seen 
by any observer who will take the pains to notice the count- 
less marks of angle-worms which frequently appear upon the 
surface of the soil after a rain. Mr. Darwin estimated that 
the amount of soil brought to the surface by worms was in 
one case at the rate of nearly two tenths of an inch a year. 
It is estimated, also, by competent authority, that the number 
of worms to an acre is as great as fifty-four thousand and 
that they would weigh three hundred and fifty-six pounds. 
Trustworthy estimates also show that these creatures some- 
times raise annually to the surface fourteen tons, and again 
eighteen tons, to the acre.t From this it is easily seen that 
the predominance of fine earth upon the surface is due to the 


* “Some Effect of Pressure of a Continental Glacier,” p. 139. 
+ See Darwin, on “ Vegetable Mould and Earth-Worms,” chaps. iii and iv. 


THE LOESS. 419 


work of such animals as worms, crayfish, and ants. But these 
creatures are limited in the depth to which they can pene- 
trate the soil and convey it to the surface. Still, it is not im- 
probable that in many places where the loess-like deposits are 
shallow it may be the result of these agencies. 

The twenty years which have elapsed since this chapter 
was written have been marked by continuous discussion of 
this puzzling problem of the loess. Butitssolution seems still 
about as far distant as ever. The Richthofen theory which 
accounts for its accumulation and distribution by wind has 
now more supporters than ever. But there is still a large 
residuum of facts that resist explanation on that theory alone. 
The loess of China has doubtless accumulated in the mountain- 
ous region bordering on Mongolia through the agency of 
wind, which has brought it in from the desert wastes which 
stretch westward to the “roof of the World” in Central 
Asia. But even so it is aquestion whether the material was not 
ultimately of glacial origin. 

In the revised edition of Geikie’s ‘“Great Ice Age’ it is rep- 
resented that an ice field covered eastern Mongolia which would 
presumably furnish the required glacial grist. But after the 
demonstration that eastern Mongolia never supported ice 
fields, the glacialists were compelled to resort to the theory 
that the wind had brought the material across the desert of 
Gobi, all the way from the base of the mountains, which on 
three sides surround the Tarim Valley. Here during the 
glacial period there was a great extension of glaciers in the 
Pamir and in the Tian Shan and the Himalaya mountains. 
It is to the floods pouring from the fronts of these glaciers that 
some would look for the supply of loess which the winds 
have brought into the mountain border of eastern Mongolia. 
It is difficult to say that this cause is not adequate to the effect, 
for the prevailing winds are westerly over this whole region 
and loess when once started could easily be driven at succes- 
sive stages for any requireddistance. I can add my personal 


420 THE ICE AGE IN NORTH AMERICA. 


testimony to the extent and effects of the dust storms in east- 
ern Mongolia, where for a day at a time the dust raised by 
the wind was so dense that objects could not be distinguished 
half way acrosstheroad. And I have described immense drifts 
of loess near the summits of the mountains in that region five 
thousand feet above the sea, where it wasimpossibleto invoke 
the agency of water to account for the accumulation. __ 

But the investigations of Huntington and others seem to 
show that loess is not exclusively of glacial origin, but may 
be the finer product of subaérial disintegration, such as is 
going on all the while in desert regions such as exist in Central 
Asia and in the Rocky Mountain plateau. Still, whatever 
be the ultimate origin of the material, and however much 
influence we may attribute to the wind in transporting it 
from its original place of formation, water must be allowed 
a large share in its final distribution, and its accumulation 
belongs to a definite period corresponding to that of the glacial 
period. Itis perfectly evident to one who traverses the moun- 
tainous region of eastern Mongolia that loess is not now 
accumulating there through the agency of wind as fast as it 
is being removed by water, and carried down to the lower 
levels of the Yangtsi and Hoang rivers, and by them distrib- 
uted along the shores of the Chinese Sea. At the same time 
there are numerous level-topped areas of loess of great size 
all over northwestern China which indicate deposition by 
water. 

The same is true of the loess in the Mississippi and Mis- 
souri valleys. While it is doubtless true that in many places 
- the accumulations are due to wind, it is equally evident that 
there are many level-topped areas of loess along the borders 
of the Missouri which betoken the height reached by the 
overflowing floods of the stream when, as already shown, it 
was gorged by silt-laden water from the melting ice in the 
closing stages of the glacial period. Both wind and water 
had their share in the distribution. The absence of true 


ae 


THE LOESS. 421 


water species of shells in the loess is what we should expect 
in an accumulation which took place in periodical or annual 
overflows. Land snails still love the flood-plains of variable 
streams. In the vicissitudes of the last stages of the glacial 
period we nave the temporary presence of water provided for 
to suit the habits of such shells as are found in the loess. 


Fie. 120.—Deep gulley in the loess at Helena, Arkansas. Courtesy of U.S. Geo. Sur- 
vey. Photo, by A, F, Crider, 


CHAPTER XVII. 


FLIGHT OF PLANTS AND ANIMALS DURING THE GLACIAL 
AGE. 


Awone the most interesting incidental effects of the Gla- 
cial period is that of its influence in distributing plants and 
animals over the lower latitudes. A glance at a polar pro- 
jection of the northern hemisphere shows to what a remark- 
able extent the land is clustered around the north pole, and 
how easy it would have been, under favorable conditions of 
climate, for plants and animals to spread from that vicinity 
along different meridians, till, in the lower latitudes, they 
should be on opposite sides of the earth. In conformity 
with these natural lines of emigration, it has long been 
known that both among plants and animals the species of 
_ the northern hemisphere are much more closely allied than 
those of the southern hémisphere, where no such land-con- 
nection exists; and, as we shall presently see, the problem 
presented by the hates of plants in the northern hemi- 
sphere is very complex and curious. For its solution we are 
largely indebted to the sagacity of the late Professor Asa 
Gray, who discovered the key in the influence of the Glacial 
period. 

In 1857, after he was already familiar, from private cor- 
respondence, with Darwin’s theory of the origin of species, 
Professor Gray was called upon to study the extensive botan- 
ical collections brought back from Japan by the expeditions 
of Commodores Perry and Rodgers. Comparison of these 
species with those in corresponding latitudes in other por- 
tions of the world brought out clearly—what had been 


FLIGHT OF PLANTS AND ANIMALS. 423 


before but dimly perceived—that there was a remarkable 
resemblance between the existing plants of eastern Asia and 
those of eastern North America, that more species are com- 
mon to Japan and Europe than to Japan and western North 


iJ 
: " 9 5 


F ia. 121.—Map showing how the land clusters about the North Pole. 


America, and that the resemblance is greatest of all between 
Japan and eastern North America. Out of three hundred 
species, common to the temperate regions of eastern Asia 


424 THE ICE AGE IN NORTH AMERICA. 


and the corresponding region of North America, only one 
third is represented in western North America. 

The key applied by Professor Gray for the solution of 
this problem was suggested by the investigations of Heer and 
others, which had brought out the fact that, during the Ter- 
tiary period, just before the beginning of the Ice age, a tem- 
perate climate, corresponding to that of latitude 35° on the 
Atlantic coast, extended far up toward the north pole, per- 
mitting Greenland and Spitzbergen to be covered with trees 
and plants similar, in most respects, to those found at the 
present time in Virginia and North Carolina. Here, indeed, 
in close proximity to the north pole, were then residing, in 
harmony and contentment, the ancestors of nearly all the 
plants and animals which are now found in the north tem- 
perate zone, and here they would have continued to stay but 
for the cold breath of the approaching Ice age, which drove 
them from their homes, and compelled them to migrate to 
more hospitable latitudes. 

The picture of the flight and diapooul of these forests, 
and of their struggle to find, and adjust themselves to, other 
homes, is second in interest to that of no other migration. 
A single tree is helpless before such a force as an advancing 
glacier, since a tree alone can not migrate. But a forest of 
trees can. Trees can “take to the woods” when they can 
do nothing else, and so escape unfavorable conditions. 
There is a natural climatic belt to which the life of a forest 
is adjusted. In the present instance, as the favorable con- 
ditions near the poles were disturbed by the cooling influ- 
ences of the glacier approaching from the north, the indi- 
vidual trees on that side of the forest-belt gradually perished ; 
but, at the same time that the favorable conditions of life 
were contracting on the north, they were expanding on the 
south, so that along the southern belt the trees could gradu- 
ally advance into new territory, and so the whole forest-belt 
move southward, following the conditions favorable to its 
existence. It is therefore easy to conceive how, with the 
slow advance of the glacial conditions from the north, the 


FLIGHT OF PLANTS AND ANIMALS. 425 


vegetation of Greenland and British America was transferred 
far down toward the torrid zone on both the Eastern and the 
Western Continent. Being once thus transferred, the forest 
would be compelled to remain there until the retreat of the 
ice began again to modify the conditions so as to compel a 
corresponding retreat of plants toward their original north- 
ern habitat. Thus it is that these descendants of the pre- 
glacial plants of Greenland, arrested in their northward 
march, have remained the characteristic flora of the latitudes 
near the glacial boundary. On the other hand, the arctic 
species, which can not endure even a temperate climate, and 
which must have accompanied the advancing glacier south- 
ward, found their natural conditions again in two ways: 1. 
By following closely upon the steps of the retreating ice to 
extreme northern latitudes; and, 2. To use Professor Gray’s 
happy expression, by “taking to the mountains,” and finding 
near their summits the necessary arctic conditions. It is 
thus that the mountains of New England and Labrador con- 
tain many species of plants nearly identical with those on the 
Alps in Europe. 

No better presentation of this subject can be given than 
that of Professor Gray himself, made in an address delivered 
in 1878, and which by the kindness of Mrs. Gray I am per- 
mitted in large part to reproduce in this connection : * 


The forests of the whole northern hemisphere in the tem- 
perate zone (those that we are concerned with) are mainly 
made up of the same or similar kinds. Not of the same spe- 
cies, for rarely do identical trees occur in any two or more 
widely separated regions; but all round the world in our zone 
the woods contain pines and firs and larches, cypresses and 
junipers, oaks and birches, willows and poplars, maples and 
ashes, and the like. Yet, with all these family likenesses 
throughout, each region has some peculiar features, some trees 
by which the country may at once be distinguished. 


* ““ Forest Geography and Archeology,” a lecture delivered before the Har- 
vard University Natural History Society, April 18, 1878, by Asa Gray. Printed 
in the “ American Journal of Science,” vol. cxvi, pp. 85-94, 183-196. 


426 THE ICE AGH IN NORTH AMERICA. 


Beginning by a comparison of our Pacific with our Atlan- 
tic forests, it is to be noted that the greater part of the trees 
familiar on the Atlantic side of the continent are conspicu- 
ously absent from the Pacific forests. 


For example, the Pacific coast has no magnolias, no tulip- 
tree, no papaw, no linden or basswood, and is very poor in 
maples ; no locust-trees—neither flowering locust nor honey- 
locust—nor any leguminous tree; no cherry large enough for 
a timber-tree, like our wild black cherry ; no gum-trees (Wyssa 
nor Liquidambar), nor sorrel-tree, nor kalmia ; no persimmon, 
or bumelia; not a holly; only one ash that may be called a 
timber-tree ; no catalpa or sassafras; not a single elm, nor 
hackberry ; not a mulberry, nor planer-tree, nor maclura ; not 
a hickory, nor a beech, nor a true chestnut, nor a hornbeam ; 
barely one birch-tree, and that only far north, where the differ- 
ences are less striking. But as to coniferous trees, the only 
missing type is our bald cypress—the so-called cypress of our 
Southern swamps—and that deficiency is made up by other 
things. But as to ordinary trees, if you ask what takes the 
place in Oregon and California of all these missing kinds, 
which are familiar on our side of the continent, I must answer 
nothing, or nearly nothing. There is the madrofia (Arbutus) 
instead of our kalmia (both really trees in some places) ; and 
there is the California laurel instead of our Southern red bay- 
tree. Nor in any of the genera common to the two does the 
Pacific forest equal the Atlantic in species. It has not half as 
many maples, nor ashes, nor poplars, nor walnuts, nor birches, 
and those it has are of smaller size and of inferior quality ; it 
has not half as many oaks, and these and the ashes are of so 
inferior economic value that (as we are told) a passable wagon- 
wheel can not be made of California wood, nor a really good 
one in Oregon... . 

Now almost all these recur, in more or less similar but not 
identical species, in Japan, north China, etc. Some of them 
are likewise European, but more are not so. Extending the 
comparison to shrubs and herbs, it more and more appears 
that the forms and types which we count as peculiar to our 
Atlantic region, when we compare them, as we first naturally 


FLIGHT UF PLANTS AND ANIMALS. 427 


do, with Europe and with our West, have their close counter- 
parts in Japan and north China; some in identical species 
(especially among the herbs), often in strikingly similar ones, 
not rarely as sole species of peculiar genera or in related ge- 
neric types. I was avery young botanist when I began to notice 
this, and I have from time to time made lists of such instances. 
Evidences of this remarkable relationship have multiplied year 
after year, until what was long a wonder has come to be so 
common that I should now not be greatly surprised if a Sarra- 
cenia or a Dionea, or their like, should turn up in eastern 
Asia. Very few such isolated types remain without counter- 
parts. It is as if Nature, when she had enough species of a 
genus to go round, dealt them fairly, one at least to each quar- 
ter of our zone; but when she had only two of some peculiar 
kind gave one to us and the other to Japan, Manchuria, or the 
Himalayas ; when she had only one, divided these between the 
two partners on the opposite side of the table. As to number 
of species generally, it can not be said that Europe and Pacific 
North America are at all in arrears ; but, as to trees, either the 
contrasted regions have been exceptionally favored or these 
have been hardly dealt with. There is, as I have intimated, 
some reason to adopt the latter alternative. 

We may take it for granted that the indigenous plants of 
any country, particularly the trees, have been selected by cli- 
mate. Whatever other influences or circumstances have been 
brought to bear upon them, or the trees have brought to bear 
on each other, no tree could hold its place as a member of any 
forest or flora which is not adapted to enduye even the extremes 
of the climate of the region or station. But the character of 
the climate will not explain the remarkable paucity of the 
trees which compose the indigenous European forest. That is 
proved by experiment, sufficiently prolonged in certain cases 
to justify the inference. Probably there is no tree of the north- 
ern temperate zone which will not flourish in some part of 
Europe. Great Britain alone can grow double or treble the 
number of trees that the Atlantic States can ; in all the latter 
we can grow hardly one tree of the Pacific coast. England 
supports all of them, and all our Atlantic trees also, and like- 
wise the Japanese and north Siberian species, which do thrive 


428 THE ICE AGE IN NORTH AMERICA. 


here remarkably in some parts of the Atlantic coast, especially 
the cooler temperate ones. ‘The poverty of the European sylva 
is attributable to the absence of our Atlantic American types, 
to its having no magnolia, liriodendron, asimina, negundo, no 
Aischulus, none of that rich assemblage of leguminous trees 
represented by locusts, honey-locusts, gymnocladus, and cla- 
drastis (even its cercis, which is hardly European, is like the 
Californian one mainly a shrub) ; no Vyssa, nor Liquidambar ; 
no Hricacee rising to a tree; no bumelia, catalpa, sassafras, 
Osage orange, hickory, or walnut ; and, as to conifers, no hem- 
lock, spruce, arbor-vitz, taxodium, nor Torreya. As compared 
with northeastern Asia, Hurope wants most of these same 
types, also the ailantus, gingko, and a goodly number of conif- 
erous genera. I can not point to any types tending to make 
up the deficiency—that is, to any not either in east North 
America or in northeast Asia, or in both. Cedrus, the true 
cedar, which comes near to it, is only north African and Asian. 
I need not say that Kurope has no Sequoia, and shares no spe- 
cial type with California. 

Now, the capital fact is, that many and perhaps almost all 
of these genera of trees were well represented in Europe 
throughout the later Tertiary times. It had not only the same 
generic types, but in some cases even the same species, or what 
must pass as such, in the lack of recognizable distinctions be- 
tween fossil remains and living analogues. Probably the Eu- 
ropean Miocene forest was about as rich and various as is ours 
of the present day, and very like it. The Glacial period came - 
and passed, and these types have not survived there, nor re- 
turned. Hence the comparative poverty of the existing Eu- 
ropean sylva, or at least the probable explanation of the ab- 
sence of those kinds of trees which make the characteristic 
difference. 

Why did these trees perish out of Europe, but survive in 
America and Asia? Before we inquire how Europe lost them, 
it may be well to ask how it got them. How came these 
American trees to be in Europe? And among the rest, how 
came Europe to have Sequoias, now represented only by our two 
big trees of California? It actually possessed two species and 
more ; one so closely answering to the redwood of the Coast 


——— 


FLIGHT OF PLANTS AND ANIMALS. 429 


Ranges, and another so very like the Sequoia gigantea of the 
Sierra Nevada, that, if such fossil twigs with leaves and cones 
had been exhumed in California instead of Europe, it would 
confidently be affirmed that we had resurrected the veritable 
ancestors of our two giant trees. Indeed, so it may-probably 
be. Celum non animam mutant, etc., may be applicable even 
to such wide wanderings and such vast intervals of time. If 
the specific essence has not changed, and even if it has suffered 
some change, genealogical connection is to be inferred in all 
such cases. . . . 

I take it that the true explanation of the whole problem 
comes from a just general view, and not through piecemeal 
suppositions of chances. And I am clear that it is to be found 


by looking to the north, to the state of things at the arctic 


zone—first, as it now is, and then as it has been. 

North of our forest regions comes the zone unwooded from 
cold, the zone of arctic vegetation. In this, as a rule, the 
species are the same round the world ; as exceptions, some are 
restricted to a part of the circle. 

The polar projection of the earth down to the northern 
tropic shows to the eye—as our maps do not—how all the lands 
come together into one region, and how natural it may be for 
the same species, under homogeneous conditions, to spread 
over it. When we know, moreover, that sea and land have 
varied greatly since these species existed, we may well believe 
that any ocean-gaps, now in the way of equable distribution, 
may have been bridged over. There is now only one consid- 
erable gap. 

What would happen if a cold period were to come on from 
the north, and were very slowly to carry the present arctic cli- 
mate, or something like it, down far into the temperate zone ? 
Why, just what has happened in the Glacial period, when the 
refrigeration somehow pushed all these plants before it down 
to southern Europe, to middle Asia, to the middle and southern 
part of the United States ; and, at length receding, left some 
part of them stranded on the Pyrenees, the Alps, the Apennines, 
the Caucasus, on our White and Rocky Mountains, or wherever 
they could escape the increasing warmth as well by ascending 
mountains as by receding northward at lower levels. Those 


430 THE ICE AGE IN NORTH AMERICA. 


that kept together at a low level, and made good their retreat, 
form the main body of present arctic vegetation. ‘Those that 
took to the mountains had their line of retreat cut off, and 
hold their positions on the mountain-tops under cover of the 
frigid climate due to elevation. ‘The conditions of these on 
different continents or different mountains are similar but not 
wholly alike. Some species proved better adapted to one, some 
to another, part of the world: where less adapted, or less 
adaptable, they have perished ; where better adapted, they con- 
tinue—with or without some change—and hence the diversifi- 
cation of Alpine plants as well as the general likeness through 
all the northern hemisphere. 

All this exactly applies to the temperate-zone vegetation, 
and to the trees that we are concerned with. ‘The clew was 
seized when the fossil botany of the high arctic regions came 
to light ; when it was demonstrated that in the times next pre- 
ceding the Glacial period—in the latest Tertiary—from Spitz- 
bergen and Iceland to Greenland and Kamchatka, a climate 
like that we now enjoy prevailed, and forests like those of New 
England and Virginia, and of California, clothed the land. 
We infer the climate from the trees; and the trees give sure ~ 
indications of the climate. 

I had divined and published the explanation long before I 
knew of the fossil plants. These, since made known, render 
the mference sure, and give us a clear idea of just what the 
climate was. At the time we speak of, Greenland, Spitzbergen, 
and our arctic sea-shore, had the climate of Pennsylvania and 
Virginia now. It would take too much time to enumerate the 
sorts of trees that have been identified by their leaves and 
fruits in the arctic later Tertiary deposits. 

I can only say, at large, that the same species have been 
found all round the world ; that the richest and most exten- 
sive finds are in Greenland ; that they comprise most of the 
sorts which I have spoken of, as American trees which once 
lived in EKurope—magnolias, sassafras, hickories, gum-trees, 
our identical Southern cypress (for all we can see of difference), 
and especially Seqguotas—not only the two which obviously 
answer to the two big trees now peculiar to California, but sev- 
eral others; that they equally comprise trees now peculiar to 


FLIGHT OF PLANTS AND ANIMALS. 431 


Japan and China, three kinds of gingko-trees, for instance, one 
of them not evidently distinguishable from the Japan species 
which alone survives; that we have evidence not merely of 
pines and maples, poplars, birches, lindens, and whatever else 
characterize the temperate-zone forests of our era, but also of 
particular species of these, so hke those of our own time and 
country, that we may fairly reckon them as the ancestors of 
several of ours. Long genealogies always deal more or less in 
conjecture ; but we appear to be within the limits of scientific 
inference when we announce that our existing temperate trees 
came from the north, and within the bounds of high proba- 
bility when we claim not a few of them as the originals of 
present species. Remains of the same plants have been found 
fossil in our temperate region, as well as in Europe. 

Here, then, we have reached a fair answer to the question 
how the same or similar species of our trees came to be so dis- 
persed over such widely separated continents. The lands all 
diverge from a polar center, and their proximate portions— 
however different from their present configuration and extent, 
and however changed at different times—were once the home 
of those trees, when they flourished in a temperate climate. 
The cold period which followed, and which doubtless came on 
by very slow degrees during ages of time, must long before 
its culmination have brought down to our latitudes, with the 
similar climate, the forest they possess now, or rather the 
ancestors of it. During this long (and we may believe first) 
occupancy of Europe and the United States, were deposited in 
pools and shallow waters the cast leaves, fruits, and occasion- 
ally branches, which are imbedded in what are called Miocene 
Tertiary, or later deposits, most abundant in Europe, from 
which the American character of the vegetation of the period 
is inferred. Geologists give the same name to these beds in 
Greenland and southern Europe, because they contain the 
remains of identical and very similar species of plants; and 
they used to regard them as of the same age on account of this 
identity. But in fact this identity is good evidence that they 
can not besynchronous. The beds in the lower latitudes must 
be later. and were forming when Greenland probably had very 
nearly the climate which it has now. 


432 THE ICE AGE IN NORTH AMERICA. 


Wherefore the high, and not the low, latitudes must be 
assumed as the birthplace of our present flora, and the present 
arctic vegetation is best regarded as derivative of the temperate. 
This flora, which, when circumpolar, was as nearly homogene- 
ous round the high latitudes as the arctic vegetation is now, 
when slowly translated into lower latitudes, would preserve its 
homogeneousness enough to account for the actual distribution 
of the same and similar species round the world, and for the 
original endowment of Kurope with what we now call Ameri- 
can types. It would also vary or be selected from by the in- 
creasing differentiation of climate in the divergent continents 
and on their different sides in a way which might well account 
for the present diversification. From an early period the sys- 
tem of the winds, the great ocean-currents (however they may 
have oscillated north and south), and the general proportions 
and features of the continents in our latitude (at least, of the 
American Continent), were much the same as now, so that 
species of plants, ever so little adapted or predisposed to cold 
winters and hot summers, would abide and be developed on 
the eastern side of continents, therefore in the Atlantic United 
States and in Japan and Manchuria: those with preference 
for milder winters would incline to the western sides; those 
disposed to tolerate dryness would tend to interiors or to re- 
gions lacking summer rain. So that, if the same thousand 
species were thrust promiscuously into these several districts, 
and carried slowly onward in the way supposed, they would 
inevitably be sifted in such a manner that the survival of the 
fittest for each district might explain the present diversity. 

Besides, there are resiftings to take into the account. The 
Glacial period or refrigeration from the north, which at its 
inception forced the temperate flora into our latitude, at its 
culmination must have carried much or most of it quite beyond. 
To what extent displaced, and how far superseded by the vege- 
tation which in our day borders the ice, or by ice itself, it is 
difficult to form more than general conjectures, so different 
and conflicting are the views of geologists upon the Glacial 
period. But upon any, or almost any, of these views it is safe 
to conclude that temperate vegetation, such as preceded the ~ 
refrigeration, and has now again succeeded it, was either thrust 


FLIGHT OF PLANTS AND ANIMALS. _ 433 


out of northern Europe and the northern Atlantic States or 
was reduced to precarious existence and diminished forms. It 
also appears that, on our own continent at least, a milder cli- 
mate than the present, and a considerable submergence of land, 
transiently supervened at the north, to which the vegetation 
must have sensibly responded by a northward movement, from 
which it afterward receded. 

All these vicissitudes must have left their impress upon 
the actual vegetation, and particularly upon the trees. They 
furnish probable reason for the loss of American types sus- 
tained by Europe. _ 

I conceive that three things have conspired to this loss: 
1. Europe, hardly extending south of latitude 40°, is all within 
the limits generally assigned to severe glacial action. 2. Its 
mountains trend east and west, from the Pyrenees to the Car- 
pathians and the Caucasus beyond, near its southern border ; 
and they had glaciers of their own, which must have begun 
their operations, and poured down the northward flanks, while 
the plains were still covered with forest on the retreat from 
the great ice-wave coming from the north. Attacked both on 
front and rear, much of the forest must have perished then 
and there. 3. Across the’line of retreat of those which may 
have flanked the mountain-ranges, or were stationed south of 
them, stretched the Mediterranean, an impassable barrier. 
Some hardy trees may have eked out their existence on the 
northern shore of the Mediterranean and the Atlantic coast. 
But, we doubt not, taxodium and Sequotias, magnolias, and 
Liquidambars, and even hickovies and the like, were among the 
missing. Escape by the east, and rehabilitation from that 
quarter until a very late period, was apparently prevented by 
- the prolongation of the Mediterranean to the Caspian, and 
thence to the Siberian Ocean. If we accept the supposition 
of Nordenskidld, that, anterior to the Glacial period, Europe 
was ‘‘bounded on the south by an ocean extending from the 
Atlantic over the present deserts of Sahara and central Asia 
to the Pacific,” all chance of these American types having 
escaped from or re-entered Europe from the south and east is 
excluded. Europe may thus be conceived to have been for a 
time somewhat in the condition in which Greenland 1s now, 


434 THE ICH AGE IN NORTH AMERICA. 


and, indeed, to have been connected with Greenland in this 
or in earlier times. Such a junction, cutting off access of the 
Gulf Stream to the Polar Sea, would, as some think, other 
things remaining as they are, almost of itself give glaciation 
to Europe. Greenland may be referred to, by way of compari- 
son, as a country which, having undergone extreme glaciation, 
bears the marks of it in the extreme poverty of its flora, and 
in the absence of the plants to which its southern portion, 
extending six degrees below the Arctic Circle, might be entitled. 
It ought to have trees, and might support them. But, since 
destruction by glaciation, no way has been open for their re- 
turn. Europe fared much better, but suffered in its degree 
in a similar way. 

Turning for a moment to the American Continent for a 
contrast, we find the land unbroken and open down to the 
tropic, and the mountains running north and south. The 
trees, when touched on the north by the on-coming retrigera- 
tion, had only to move their southern border southward, along 
an open way, as far as the exigency required ; and there was 
no impediment to their due return. Then the more southern 
latitude of the United States gave great advantage over Ku- 
rope. On the Atlantic border, proper glaciation was felt only 
in the northern part, down to about latitude 40°. In the in- 
terior of the country, owing doubtless to greater dryness and 
summer heat, the limit receded greatly northward in the Mis- 
sissippi Valley, and gave only local glaciers to the Rocky 
Mountains ; and no volcanic outbreaks or violent changes of 
any kind have here occurred since the types of our present 
vegetation came to the land. So our lines have been cast in 
pleasant places, and the goodly heritage of forest-trees is one 
of the consequences. fs 

The still greater richness of northeastern Asia m arboreal 
vegetation may find explanation in the prevalence of particu- 
larly favorable conditions, both ante-glacial and recent. The 
trees of the Miocene circumpolar forest appear to have found 
there a secure home; and the Japanese Islands, to which most 
of these trees belong, must be remarkably adapted to them. 
The situation of these islands—analogous to that of Great 
Britain, but with the advantage of lower latitude and greater 


FLIGHT OF PLANTS AND ANIMALS. 435 


sunshine—their ample extent north and south, their diversified 
configuration, their proximity to the great Pacific Gulf Stream, - 
by which a vast body of warm water sweeps along their accentu- 
ated shores, and the comparatively equable diffusion of rain 
throughout the year, all probably conspire to the preservation 
and development of an originally ample inheritance. 

The case of the Pacific forest is remarkable and paradoxi- 
cal. It is, as we know, the sole refuge of the most character- 
istic and wide-spread type of Miocene Conifere, the Sequovas ; 
it is rich in coniferous types beyond any country except Japan ; 
in its gold-bearing gravels are indications that it possessed, 
seemingly down to the very beginning of the Glacial period, 
Magnolias and beeches, a true chestnut, Liquidambar, elms, 
and other trees now wholly wanting to that side of the conti- 
nent, though common both to Japan and to Atlantic North 
America. Any attempted explanation of this extreme paucity 
of the usually major constituents of forest, along with a great 
development of the minor or coniferous element, would take 
us quite too far, and would bring us to mere conjectures. 

Much may be attributed to late glaciation ; something to 
the tremendous outpours of lava which, immediately before 


_the period of refrigeration, deeply covered a very large part of 


the forest area ; much to the narrowness of the forest-belt, to 
the want of summer rain, and to the most unequal and pre- 
carious distribution of that of winter. 

Upon all these topics questions open which we are not pre- 
pared to discuss. I have done all I could hope to do in one 
lecture if I have distinctly shown that the races of trees, like 
the races of men, have come down to us through a prehistoric 
(or pre-natural-historic) period ; and that the explanation of 
the present condition is to be sought in the past, and traced in 
vestiges, and remains, and survivals; that for the vegetable 
kingdom also there is a veritable archeology. 


As the truth of a theory needs to be tested by the meth- 
od of difference as well as of agreement, we turn to inquire 
if it be not true that all mountains which reach above the 
snow-line have an Alpine flora, and whether it be not the 
conditions themselves which determine the peculiarities ? 


436 THE ICE AGE IN NORTH AMERICA. 


These questions are answered by an appeal to certain oceanic 
islands which were outside the influence of continental glacia- 
tion. According to Wallace, a striking proof of the theory 
presented by Professor Gray ‘is found on the Peak of Ten- 
eriffe, a mountain 12,000 feet high. In the uppermost 4,500 
feet of this mountain above the limit of trees, Von Buch 
found only eleven species of plants, eight of which were 
peculiar; but the whole were allied to those found at lower 
elevations. On the Alps or Pyrenees, at this elevation, 
there would be a rich flora comprising hundreds of arctic 
plants ; and the absence of anything corresponding to them 
in this case, in which their ingress was cut off by the sea, is 
exactly what the theory leads us to expect.” * 

On both continents, at the close of the Tertiary period, 
there occurred a remarkable extinction of animals which is 
doubtless connected with the advance of the continental ice- 
sheet. Among these we may mention two species of the 
cat family as large as lions; four species of the dog family, 
some of them larger than wolves; two species of bears; a 
walrus, found in Virginia; three species of dolphins, found 
in the Eastern States; two species of the sea-cow, found in . 
Florida and South Carolina; six species of the horse; the 
existing South American tapir; a species of the South Amer- 
ican llama; a camel; two species of bison; three species of © 
sheep; two species of elephants and two of mastodons; a 
species of Megatherium, three of Megalonyx, and one of 
Mylodon—huge terrestial sloths as large as the rhinoceros, or 
even as large as elephants, which ranged over the Southern 
States to Pennsylvania, and the Mylodon as far as the Great 
Lakes and Oregon.t 

This wondrous assemblage of animals became extinct upon 
the approach of the Glacial period, as their remains are all 
found in post-Pliocene deposits. The intermingling of forms 
is remarkable. The horses, camels, and elephants which 


* “The Geographical Distribution of Animals,” vol. i, p. 43. 
+ Ibid., p. 129. 


FLIGHT OF PLANTS AND ANIMALS. 437 


lived in North America before the Glacial period were found 
subsequent to the Glacial period only in the Old World, 
while the llamas, tapirs, and gigantic Hdendata are South 
American types. The progress of events seems to Lave been 
about as follows: In the warm period preceding the Glacial 
epoch, when the vegetation of the temperate zone flourished 
about the north pole, there was land connection between 
the continents, permitting the larger species of the Old World 
to migrate to North America. At the same time the con- 
ditions in North America were favorable to the tropical spe- 
cies of animals which had developed and flourished in South 
America. The refrigeration of the climate on the approach 
of the Glacial period, and the advance of the ice from the 
north, cut off retreat to the Old World species, and gradually 
hemmed them in over the southern portion of the continent, 
where all forms of life were compelled to readjust themselves 
to new conditions. The struggle for existence probably re- 
sulted, first, in the extinction of those South American spe- 
cies which had invaded North America during the warmer 
climate of later Tertiary times; and the more hardy emi- 
grants from the north would have the advantage from the 
similarity in climate in the southern United States during 
the Glacial period to that about the poles, where they had 
flourished immediately before. With the withdrawal of ice 
to the north, the struggle of these animals with the condition 
of existence began anew, and the mammoth and some others 
found themselves unable to cope with the changes to which 
they were compelled to adjust themselves. From the abun- 
dance of remains of these animals found in the peat-bogs of 
kettle-holes and in the glacial terraces of gravel and loess, it 
is evident that they followed close upon the retreating ice- 
front, and some of them continued the retreat to the Arctic 
Circle, where they still live and flourish; while others, like 
the elephant and mastodon, perished. 

Few things are better calculated to impress the scientific 
imagination than this dispersion and final extinction in North 
America of so many large animals native to the Old World; 


438 THE ICE AGE IN NORTH AMERICA. 


while some of them, like the horse, were admirably adapted 
to the present conditions, as is shown by their rapid increase 
since their introduction after the discovery of America by 
the whites. In a succeeding chapter we shall also see that 
man himself participated in this struggle with the new con- 
ditions introduced by the Glacial period on this continent, 
and that, in company with the mammoth, walrus, and other 
arctic species, he followed up the retreating ice both upon 
the Atlantic coast and in the Mississippi Valley. Whether, 
like some of his companions, he was unsuccessful in the con- 
test is not certain, though there is much to be said in favor 
of the theory that the Eskimos of the north are the lineal 
descendants of the preglacial men whose implements are 
found in New Jersey, Ohio, and Minnesota. Much also may 
be said to support the theory, alluded to by Professor Olay- 
pole, connecting the traditions of the destruction of large 
portions of the human race by a flood with the extermination 
of species naturally brought about by the conditions accom- 
panying the floods which closed the Glacial period. 

It is interesting to observe, also, that insects as well as 
plants and the larger animals were compelled to reckon with 
the Glacial period. They, too, participated in the southern 
migration enforced by the advancing ice, and also shared in the 
vicissitudes of its final retreat, compelling them to escape from 
the warmer belt of climate which again advanced upon them 
from the south. Like the forms of arctic and Alpine vegeta- 
tion, a portion of the insects also took to the mountains, 
where they still remain, as living witnesses to the reality of 
the Glacial period. The summits of the White Mountains 
are characterized by Alpine species of insects, one of which is 
thus described by Mr. Samuel Seudder : 


But even the narrow limit of the Alpine zone of the White 
Mountains claims for its own a single butterfly, which probably 
has a more restricted range than any other in the world. One 
may search the season through over the comparatively vast and 
almost equally barren elevations within the sub-Alpine district 
of the White Mountains and fail to discover more than here 


FLIGHT OF PLANTS AND ANIMALS. 439 


and there a solitary individual whirled by fierce blasts down 
the mountain-slopes, while, a few hundred feet above, the but- 
terflies swarm in great numbers. Every passage of the sun 
from behind a cloud brings them out in scores, and they may 
often be captured as fast as they can be properly secured. The 

contrast between the occasional and unwilling visitor in the 
sub-Alpine region and the swarms which flutter about the 
upper plateaus is most significant. Yet the Carices, the food- 
plant of the caterpillar, are quite as abundant in the lower 
regions as in the upper, even to the species C. rigida, upon 
which I found the larva feeding. Now, this butterfly (@nevs 
semidea) belongs to a genus which is peculiar to Alpine and 
arctic regions ; in fact, it is the only genus of butterflies which 
is exclusively confined to them. It has numerous members, 
both in this country and in the Old World. One is confined 
to the Alps of Europe ; most of the European species, however, 
are found only in the extreme north. The genus extends 
across the whole continent of America, and several of its spe- 
cies occur on the highest elevations of the Rocky Mountains. 
Several species are common to Europe and America, and it is 
to one of these that @neis senndea is most closely allied. A 
few species descend into the Hudsonian fauna, but, as a whole, 
the genus has its metropolis farther north. So that, im ascend- 
ing Mount Washington, we pass, as it were, from New Hamp- 
shire to northern Labrador; on leaving the forests, we come 
first upon animals recalling those of the northern shores of the 
Gulf of St. Lawrence and the coast of Labrador opposite New- 
foundland ; and, when we have attained the summit, we find 
insects which represent the fauna of Atlantic Labrador and the 
southern extremity of Greenland.* 


Commenting upon these and similar facts connected with 
other species of butterflies and with several species of moths, 
Mr. A. R. Grote pertinently says : + 


The question comes up with regard to the White Mountain 
butterfly, as to the manner in which this species of Geis 


—— 


* “Geology of New Hampshire,” vol. i, pp. 340, 341. 
+ “ American Journal of Science,” vol. cx, 1875, pp. 337, 338. 


440 THE ICE AGH IN NORTH AMERICA. 


attained its present restricted geographical area. ... How 
did the White Mountain butterfly get up the White Mount- 
ains? Iam disposed to answer, by the action attendant on 
the decline of the Glacial period. . 

The main ice-sheet had nae ‘Hien insensibly before it, 
and, during the continuance of the Glacial period, the geo- 
graphical distribution of the genus Geis had been changed 
from a high northern region to one which may well have in- 
cluded portions of the Southern States. And, on its decline, 
the ice-sheet drew them back again after itself by easy stages ; 
yet not all of them. Some of these butterflies strayed by the 
way, detained by the physical nature of the country, and 
destined to plant colonies apart from their companions. When 
the main ice-sheet left the foot of the White Mountains, on its 
long march back to the pole, where it now seems to rest, some 
of these wayward, flitting Geis butterflies were left behind. 
These had strayed up behind the local glaciers on Mount 
Washington, and so became separated from the main body of 
their companions, which latter journeyed northward, follow- 
ing the course of the retirement of the main ice-sheet. They 
had found in elevation their congenial climate, and they have 
followed this gradually to the top of the mountain, which they 
have now attained, and from which they can not now retreat. 
Far off mm Labrador the descendants of their ancestral com- 
panions fly over wide stretches of country, while they appear 
to be in prison on the top of a mountain. I conceive that in this 
way the mountains may generally have secured their Alpine 
animals. The Glacial period can not be said strictly to have 
expired. It exists even now for high levels above the sea, 
while the Eskimos find it yet enduring in the far north. Had 
other conditions been favorable, we might now find arctic 
man living on snow-capped mountains within the temperate 
zone. 

At a height of from 5,600 to 6,200 feet above the level of 
the sea, and a mean temperature of about 48° during a short 
summer, the White Mountain butterflies (Geis semidea) yet 
enjoy a climate like that of Labrador within the limits of New 
Hampshire. And in the case of moths an analogous state of 
things exists. The species Anarta melanopa is four _on Mount 


FLIGHT OF PLANTS AND ANIMALS. 441 


Washington, the Rocky Mountains, and in Labrador. <Agrotis 
Islandica is found in Iceland, Labrador, in the White Mount- 
ains, and perhaps in Colorado. As on islands in the air, these 
insects have been left by the retiring ice-flood during the open- 
ing of the Quaternary. 

On inferior elevations, as on Mount Katahdin, in Maine, 
where we now find no @neis butterflies, these may formerly 
have existed, succumbing to a climate gradually increasing in 
warmth from which they had no escape; while the original 
colonization, in the several instances, must have always greatly 
depended upon local topography. 

In a Russian Government Report made in 1900, is found 
a list of plants occurring in the provinces of Okhotsk and Kam- 
chatka. This list contains 746 species of phaenogamous or 
flowering plants, 173 identicalspecies of which are common to 
North America, that is, twenty-three per cent are found in 
North America. Many of these species are distributed uni- 
versally through the North Temperate Zone, and twenty-one 
are knownto have been introduced into America from Europe, 
but have become naturalized. If now we compare the flora 
of Manchuria, using the list published in the Russian Govern- 
ment Report on Manchuriafor 1897, with that on Kamchatka 
and Okhotsk for 1900, we find that there are 193 identical 
species common to both, that is, nearly twenty-six per cent, 
only five per cent more than that with North America. Of 
the 173 species common to North America and the Provinces 
of Okhotsk and Kamchatka, seventy-seven are also found 
in Manchuria. Out of the 284 genera found in Okhotsk 
and Kamchatka there are sixty-two genera not to be found 
in North America. This number will probably be increased 
when the Kamchatkan flora has been better studied, for the 
region is so inaccessible that the lists at present must be 
quite incomplete. 

The following list gives the plants common to the Okhotsk- 
Kamchatkan region and North America, those marked with 
a (*) are common to Manchuria also. 


442 


Anemone pennsylvanica, L. 
*A. nemorosa, L. 

A. parviflora, Mich. 
Ranunculus Flammula, L. 
R. Cymbalariz, Purch. 

*R. repens, L. 

Caltha palustris, L. 

Coptis trifolia, Salsb. 
Actaea spicata, L. 

Chelidonium majus, L. 
Dicentra lachenaliaeflora, 

Ldb. 

Nasturcium palustre, Leyss. 
*Barbarea vulgaris, R. Br. 
Arabis hirsuta, Scop. 

Cardamine bellidifolia, L. 

C. pratensis,’ L. 

Draba incana, L. 

*D. nemorosa, L. 
*Thlaspi arvense, L. 
*Capsella Birsa pastoris, L. 
*Sisymbrium Sophia, L. 
*Erysimum cheiranthoides, L. 
Viola palustris, L. 
V. blanda, Hook. 
*V. canina, L. 

Drosera rotundifolia, L. 
*Stellaria media, Willd. 

*S. borealis, MB. 

S. humifusa, Rot. 

*S. longifolia, Muhl. 
*S. longipes, Gold. 

Cerastium vulgatum, L. 
*C. arvense, L. 

Linum perenne, L. 
*Geranium sibiricum, L. 
*Oxalis Acetosella, L. 

Trifolium medium, L. 


THE ICE AGE IN NORTH AMERICA. 


T. pratense, L. 

Oxytropis campestris, D.C. 

Astragalus alpinus, L. 
*Vicia eracca, 1. 

*Lathyrus palustris, L. 

L. pratensis, L. 

*Spiraea betulifolia, L. 

*S. salicifolia, L. 

*Gum strictum, Ait. 

G. macrophyllum, Willd. 

Potentilla norvegica, L. 

P. Anserina, L. 

*P. fruticosa, L. 

*Fragaria vesca, L. 

Pyrus sambucifolia, Cham. 

et Schlect. 

*Epilobium angustifolium, L. 
Hippuris vulgaris, L. 
Claytonia virginica, L. 
Sedum Rhodiola, D.C. 

*Ribes rubrum, L. 
Saxifraga oppositifolia, L. 

*Chrysosplenium alternifolia, 

L. 

Mitella nuda, L. 

Ligusticum scoticum, L. 

Coelopleurum Gmelini, Ldb. 

Carum carui, L. 

Cornus canadensis, L 
*Adoxa Moschatellina, L. 
*Sambucus racemosa, L. 
*Linnea borealis, L. 

*Galium Aparine, L. 

G. trifidum, L. 

*G. verum. L. 

*Erigeron acris, L. 
Solidago Virgaurea, L. 

*Achillea millefolium, L. 


FLIGHTS OF PLANTS AND ANIMALS. 


A. Ptarmica, L. 
Matricaria discoidea, D.C. 
Tanacetum vulgare, L. 
Artemisia biennis, Willd. 
A. Stelleriana, Bess. 


*Gnaphalium ugliginosum, L. 
*Senecio pseudo-Arnica, Less. 


*Picris hieracioides, L. 


*Taraxacum officinale, Wigg. 


Crepis tectorum, L. 
*Vaccinium Vitis-Idaea, L. 
V. uliginosum, L. 


Arctostaphylus alpina, Sprgl. 


A. uva ursi, Sprgl. 
Andromeda polifolia, L. 


Phyllodoce taxifolia, Salsb. 
Loiseuria procumbens, Desv. 


*Ledum palustre, L. 
*Pyrola rotundifolia, L. 
P. minor, L. 
P. secunda, L. 


*Moneses grandiflora, Salsb. 


*Utricularia intermedia, 
| Hayne. 

Primula farinosa, L. 
*Lysimachia thyrsiflora, L. 
Samolus Valerandi, L. 
Gentiana Amarella. L. 
*Menyanthes trifoliata, L. 


*Polemonium coeruleum, L. 
*Mertensia maritima, G. Don. 


*Echinospermum Lappula, 
Lehm. 

*E. deflexum, Lehm. 
Limostella aquatica, L. 
Veronica Anagallis, L. 

VY. serpyllifolia, L. 
Castelleja pallida, Kunt. 


443 


*Kuphrasia officinalis, L. 
*Mentha arvensis, L. 
Thumus Serpyllum, L. 
*Nepeta Glechoma, Benth. 
Scutellaria galericulata, L. 
Galeopsis Tetrahit, L. 
*Plantago major, L. 
*Rumex acetosa, L. 
*Polygonum Bistorta, L. 
*P. viviparum, L. 
*P. aviculare, L. 
P. convolvolus, L. 
Empertum nigrum, L. 
Salix phylicifolia, L. 
*S. myrtilloides, L. 
*Populus tremula, L. 
=P alba, is: ; 
*“Humulus Lupulus, Ldb. 
*Urtica dioica, L. 
*Alnus incana, Willd. 
Myrica Gale, L. 
*Juniperus communis, L. 
*Chenopodium album, L. 
Atriplex patula, L. 
Sparganium simplex, Huds. 
Acorus calamus, L. 
Zostera marina, L. 
Potamogeton praelongus. 
Wulf. 
P. perfoliatus, L. 
Triglochin palustris, L. 
Alisma plantago, L. 
Corallorhiza innata, R. Br. 
*Microstylis monophylla, 
Lindl. 
Calypso borealis, Salisb. 
“treptopus amplexifolius, 
DAZ 


444 THE ICE AGE IN NORTH AMERICA. 


Smilicina trifolia, Desv. 


Allium Schoenoprasum, L. 


*Veratrum viride, Ait. 
Luzula spadicea. 

*L. campestris, D.C. 
Juncus balticus, Dethar. 
J. filiformis, L. 

J. articulatus, L. 


Eriophorum vaginatum, L. 


Carex alpina, Sw. 

C. vulgaris, Fries. 
*C. stenophylla, Wahl. 

C. rariflora, Smit. 
*Elymus mollis, Trin. 

Festuca ovina, L. 

Poa laxa, Henke. 
*P. pratensis, L. 

P. compressa, L. 

P. serotina, Ehrh. 
*P. nemoralis, L. 

P. annua, L. 


*Hierochloa borealis, R. et 


Sch. 


*Equisetum pratense, Chrk. 


E. limosum, L. 

*K. silvaticum, L. 
E. variegatum, Sehleich. 
E. scirpoides, Mich. 

*EK. arvense, L. 


*H. hyemale, L. 
Lycopodium Selago, L. 
*L. annotinum, L. 


— *L. alpinum, L. 


*L. complanatum, L. 
*L. clavatum, L. 
Selaginella rupestris, Spring. 
H. alpina, R. et. Sch. 
Deschampsia caespitosa, P. 
Bea. 
Calamagrostis Langsdorffii, 
Trin. 
Agrostis canina, L. 
Trisetum subspicatum, 
Beanv. 
*Phleum alpinum, L. 
Cryptogamia 
Botrychium Lunaria, Sw. 
Polypodium vulgare, L. 
*Woodsia ilvensis, R. Br. 
W. glabella, R. Br. 
Aspidum fragrans, Sw. 
*Crystopteris fragilis, Bernh. 
*Asplenium Folix-foemina, 
Bernh. 
*Pteris aquillina, L. 
*Adianthum pedatum, L. 
Struthiopteris germanica, 
Willd. . 


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CHAPTER XVIII. 


EUROPE DURING THE GLACIAL PERIOD. 


At this point it will be profitable to take a survey of the 
condition of some other parts of the world during the great 
Ice age. By the same marks which determine the extent 
of the glacier in America, it is evident that the existing gla- 
ciers of Switzerland and Norway are but remnants of what 
formerly existed in these localities. 

James Geikie’s statement of the situation in the ed 
Isles is sufficiently complete : 


During the climax of the Glacial period all Scotland was 
drowned in a wide-spread mer de glace, which coalesced in the 
north and east with a similar sheet of ice, that crept outward 
from Scandinavia. To the west the Scottish ice, meeting with 
no impediment to its course, overflowed the outer Hebrides to 
a height of 1,600 feet, and probably continued on its path into 
the Atlantic as far as the edge of the 100-fathom plateau, where 
the somewhat sudden deepening of the sea would allow it to 
break off and send adrift whole argosies of icebergs. The 
height reached by the upper surface of the ice that over- 
whelmed the outer Hebrides enables us to ascertain the angle 
of slope between those islands and the mainland. ‘This was 
1 in 211—that is to say, the inclination of the surface of the 
ice-sheet was about twenty-five feet in the mile—an inclination 
which would appear to the eye almost like a dead level. .. . 

The ice flowed off Ireland in all directions save to northeast 
_ In Antrim, upon the coast of which it encountered the Scottish 
mer de glace, which forced it to turn away to northwest and 
southeast ; but along the whole western and southern shores, 


446 THE ICE AGE IN NORTH AMERICA. 


where no obstacle to its passage intervened, it seems to have 
swept in one broad and continuous stream out—probably as 


. far as that of Scotland—into the Atlantic. The thickness 


attained by the ice that flowed into the Irish Sea from Scot- 
land, where it coalesced with the mer de glace coming from 
the eastern seaboard of Ireland, and also, as we shall presently 
see, with that creeping out from England and Wales, makes 
it quite certain that the area now occupied by that sea must 
at that time have been filled with glacier ice... . 

The North Sea was filled with a massive mer de glace con- 
tinually advancing in a general south-southwestern direction, 
the presence of which is distinctly traceable in the remarkable 
deflections of the glaciation all along the seaboard of Scotland 
from Stonehaven southward. It was simply owing to the 
superior elevation and extent of the Scottish mountains that 
the narrow strip of low-lying ground in the eastern maritime 
districts of that country was not invaded by an alien ice-stream. 
When we pass into England the hills become lower, and the 
area of low ground between the hills and the sea increases in 
breadth. There was thus less and less opposition offered to 
the southward advance of the North Sea mer de glace as it 
pressed upon the eastern shores of England, until eventually 
it overflowed bodily and crept southward across the midland 
table-land on its way to the valley of the Severn and the Bristol 
Channel. This remarkable glacial invasion is proved not only 
by the carry of local stones, and stones which have come south 
from the northern counties and Scotland. but by the appear- 
ance in the till at Cornelian Bay and Holderness of bowlders 
of two well-known Norwegian rocks, which were recognized 
by Mr. Amund Helland. ... 

The ice which would thus appear to have streamed trans- 
versely across England eventually coalesced with that which 
overflowed from the basin of the Irish Sea southeast through 
Cheshire, together with that which streamed east from the 
Welsh uplands, and the united mer de glace thereafter made 
its way into the Bristol Channel. Here it joined the thick 
ice that flowed out to sea from the high grounds of South 
Wales, the bottom-moraine of which is conspicuous not only 
in the mountain-valleys of that region, but also upon the low- 


EUROPE DURING THE GLACIAL PERIOD. 447 


lying tracts that extend from the hills to the sea. In the south- 
eastern counties, so far as we know at present, the ice-sheet at 
the climax of the Glacial period did not extend farther than 
the valley of the Thames, beyond which no trace of its bottom- 
moraine has been met with.* 


Professor A. Geikie summarizes the facts concerning the 
continent as follows: 


In Scandinavia the ice-striz run westward and southwest- 
ward on the Norwegian coasts, and eastward or southeastward 
across the lower grounds of Sweden. When the ice descended 
into the basin of the Baltic and the plains of northern Ger- 
many, it moved southward and southwestward, but seems to 
have slightly changed its direction in different areas and at 
different times. Its movements can be made out partly from 
the strize on the solid rock, but more generally from the glacial 
drift which it has left behind. Thus it can be shown to have 
moved down the Baltic into the North Sea. At Berlin its 
movement must have been from east to west. But at Leipsic, 
as recently ascertained by Credner, it came from north-north- 
west to south-southeast, being doubtless shed off in that direc- 
tion by the high grounds of the Harz Mountains. Its southern 
limit can be traced with tolerable clearness from Jevennaar, in 
Holland, eastward across the Rhine Valley, along the base of 
the Westphalian hills, round the projecting promontory of 
the Harz, and then southward through Saxony to the roots of 
the Erzgebirge. Passing next southeastward along the flanks 
of the Riesen and Sudeten chain, it sweeps across Poland into 
Russia, circling round by Kiev, and northward by Nijni-Nov- 
gorod toward the Urals. It has been estimated that, excluding 
Finland, Scandinavia, and the British Isles, the ice must have 
covered no less than 1,700,000 square kilometres of the present 
lowlands of Europe... . 

The ice is computed to have been at least between 6,000 
and 7,000 feet thick in Norway, measured from the present 
sea-level. From the height at which its transported débris 
has been observed on the Harz, it is believed to have been at 


* “ Prehistoric Europe,” pp. 189, 190, 192, 193. 


A448 THE ICE AGE IN NORTH AMERICA. 


least 1,470 feet thick there, and to have gradually risen in ele- 
vation as one vast plateau, like that which at the present time 
covers the interior of Greenland. Among the Alps it attained 
almost incredible dimensions. The present snow-fields and 
glaciers of these mountains, large though they are, form no 
more than the mere shrunken remnants of the great mantle of 
snow and ice which then overspread Switzerland. In the 
Bernese Oberland, for example, the valleys were filled to the 
brim with ice, which, moving northward, crossed the great 
plain, and actually overrode a part of the Jura Mountains, for 
huge fragments of granite and other rocks from the central 
chain of the Alps are found high on the slopes of that range 
of heights. * 

More recently the late Professor H. Carvill Lewis studied 
the field in Great Britain, and published conclusions some- 
what different from those which had been before accepted. 
He traced, according to the summary given by Upham, a 
terminal moraine “across southern Ireland from Tralee on 
the west to the Wicklow Mountains and Bray Head southeast 
of Dublin; through the western, southern, and southeastern 
portions of Wales; northward by Manchester, and along the 
Pennine Chain to the southeast edge of Westmoreland, thence 
southeast to York, and again northward to the Tees, and 
thence southeastward along the high coast of the North Sea 
to Flamborough Head and the mouth of the Humber.” t 

Professor Lewis propounded the theory that the supposed 
glacial deposits in England south of this line of terminal 
moraine were to be explained as water-deposits in a glacial 
lake produced by the damming up of the Humber River and 
a slight elevation of the earth at the Straits of Dover. It 
is proper to say, also, that in this theory Professor Lewis had 
been in part anticipated by Professor Boyd Dawkins, who 
had written as follows: 


The ice at this time was sufficiently thick to override 
Schihallion, in Perthshire, at a height of 3,500 feet, and the 


* “ Text-Book of Geology,” pp. 885, 886. 
+ “The American Geologist,” vol. ii, 1888, p. 375. 


EUROPE DURING THE GLACIAL PERIOD. 449 


hills of Galway and Mayo at 2,000 feet. Its southern limit in 
Britain is uncertain. According to Professor Ramsay and Dr. 
James Geikie, it extended as far south as the latitude of Lon- 
don , but the hypothesis upon which this southern extension 
is tounded—that the bowlder-clays have been formed by ice 
melting on the land—is open to the objection that no similar 
clays have been proved to have been so formed, either in the 
arctic regions, where the ice-sheet has retreated, or in the dis- 
tricts forsaken by the glaciers in the Alps or Pyrenees, or in 
any other mountain-chain. Similar deposits, however, have 
been met with in Davis Strait and in the North Atlantic, 
which have been formed by melting icebergs; and we may, 
therefure, conclude that the bowlder-clays have had a like 
origin. .. . The English bowlder-clays, as a whole, differ 
from the moraine profonde in their softness and the large area 
which they cover. Strata of bowlder-clay at all comparable 
to the great clay mantle covering the lower grounds of Britain 
north of the Thames are conspicuous by their absence from 
the glaciated regions of central Europe and the Pyrenees, which 
were not depressed beneath the sea.* 


Professor Lewis’s views are of such interest that our treat- 
ment of the subject would be incomplete without a fair pre- 
sentation of them, which can best be done in his own words: 


The great ice-sheet which once covered northern England 
was found to be composed of a number of glaciers, each of 
which was bounded by its own lateral and terminal moraines. 
These glaciers were studied in detail, beginning with the east 
of England ; and the North Sea Glacier, the Wensleydale Gla- 
cier, the Stainmoor Glacier, the Aire Glacier, the Irish Sea 
Glacier, and the separate Welsh glaciers were each found to 
be distinguished by characteristic bowlders, and to be defined 
by well-marked moraines. The terminal moraine of the North 
Sea Glacier, filled with Norwegian bowlders, may be seen in 
Holderness, extending from the mouth of the Humber to 
Flamborough Head, and consists of a series of conical hills 
inclosing meres. The moraine of the Stainmoor Glacier, char- 


* “arly Man in Britain,” pp. 116, 117. 


450 THE ICE AGE IN NORTH AMERICA. 


acterized by blocks of Shap granite, may be followed northward 
along the coast past Scarborough and Whitby ; then west along 
the Cleveland Hills; then south again through Oulston to the 
city of York ; then west to near Allerton, where the Stainmoor 
Glacier is joined by the Wensleydale Glacier, a fine medial 
moraine marking the line of junction. The Wensleydale Gla- 
cier is characterized by bowlders of carboniferous limestone 
and sandstone, and its lateral moraine is followed northward 
through Wormald Green, Markington, Fountains Abbey, and 
along the Permian outcrop to Masham, where it turns west to 
Wensleydale, passing Jervaulx Abbey, and running up the val- 
ley. North of Wensleydale the moraine of the Stainmoor Gla- 
cier is followed through Richmond to Kirby Ravensworth, and 
westward to the mountains, where the glacier attained an eleva- 
tion of two thousand feet. Thus the Stainmoor Glacier, a tongue 
of the great Irish Sea Glacier, had been divided into two branches 
by the Oleveland Hills, one branch going south to the city of 
York, which is built on its terminal moraine, the other branch 
flowing out of the Tees, and being deflected southward along the 
coast by the North Sea Glacier, with which it became confluent. 

The Irish Sea Glacier, the most important glacier of Eng- 
land, came down from Scotland, and being re-enforced by local 
ice-streams, and flowing southward until it abutted against the 
mountains of Wales, it was divided into two tongues, one of 
which flowed to Wellington and Shrewsbury, while the other 
went southwest across Anglesey into the Irish Sea. This great 
glacier and its branches are all outlined by terminal moraines. 
A small tongue from it, the Aire Glacier, was forced eastward 
at Skipton and has its own distinctive moraine. In the neigh- 
borhood of Manchester the great moraine of this Irish Sea Gla- 
cier may be followed through Bacup, Hey, Stalybridge, Stock- 
port, and Macclesfield, being as finely developed as the moraines 
of Switzerland and America. South of Manchester, it contains 
flint and shell fragments, brought by the glacier from the sea- 
bottom over which it passed. At Manchester the ice was at least 
fourteen hundred feet thick, being as thick asthe Rhéne Glacier.* 


* Abstract by the author of a paper read at the Birmingham meeting of the 
British Association, September, 1886. 


EUROPE DURING THE GLACIAL PERIOD. 451 


In a paper before the British Association in September, 
1887, Professor Lewis presented his views in greater detail, 
and answered objections, alleging that— 


The hypothesis of extra-morainic fresh-water lakes, dammed 
up by the glaciers, is sustained by all observed facts. The 
most important of these lakes was one caused by the obstruc- 
tion of the mouth of the Humber by the North Sea Glacier, 
whose terminal moraine crosses that river at its mouth. This 
large lake reached up to the 400-foot contour line, and ex- 
tended southward nearly to London, and westward in finger- 
like projections into the many valleys of the Pennine Chain. 
It deposited the ‘‘ great chalky bowlder-clay,” and erratics 
were floated in all directions by icebergs. It was bounded in 
the vale of York by the Stainmoor Glacier, and Charnwood 
Forest was an island in it. At its flood period it overflowed 
southwestward by torrential streams into the Severn Valley 
and elsewhere, carrying the ‘‘ Northern Drift” into the south 
of England. Other glaciers in England were bordered by simi- 
lar but smaller lakes wherever they advanced against the drain- 
age. ‘Three such lakes were made by the Aire Glacier, the 
largest of them extending to Bradford. The Irish Sea Glacier 
caused many similar lakes high up on the west side of the 
Pennine Chain, and at its southern end north of Wolverhamp- 
ton. The overflow streams from the most southern of these 
lakes joined those issuing from Lake Humber in the Birming- 
ham district, characterized by a ‘“‘commingling of the drift,” 
otherwise inexplicable. An examination of the supposed evi- 
dences for glaciation, and for a great marine submergence in 
central and southern England, shows that neither theory is 
sustained by the facts. Thus, the supposed strize on Rowley 
Rag prove to be root-marks or plow-marks; those reported 
at Charnwood Forest to be due to running water, or perhaps 
icebergs; the supposed drift on the chalk-wolds to be a local 
wash of chalk-flints ; the high-level gravels on the Cotteswold 
Hills to be preglacial ; the shells at Macclesfield, Moel Tryfan, 
and Three Rock Mountain to be glacier-borne, and not a proof 
of submergence ; the drift on the Pennine plateau of north 
Derbyshire to be partly made by icebergs floating in Lake 


452 THE ICE AGE IN NORTH AMERICA. 


Humber, and partly a decomposed millstone grit or Bunter ° 


sandstone ; and the supposed Welsh erratics on Frankley Hill 
at a height of eight hundred feet to be in place and due to an 
outcrop of the paleozoic floor. 

The conclusion that the glacial phenomena of England are 
due neither to a universal ice-cap nor to a marine submergence, 
but to a number of glaciers bordered by temporary fresh-water 
lakes, is in accordance with all the observations of the author 
in England and elsewhere. * 


It is fair to add, however, that soon after this meeting of 
the British Association at which this paper was read, his 
observations at Frankley Hill, in Worcestershire, and west- 
ward, led Professor Lewis to waver in his views, and he had 
resolved to go over all the ground again; but his untimely 
death prevented the accomplishment of this plan. Probably 
there can be little doubt of the correctness of Mr. Upham’s 
conclusion that, if Lewis had lived, he would have accepted 
the opinions of the majority of the geologists of Great Brit- 
ain, that land-ice really extended at one time as far south as 
the Thames. ‘Still, small portions of northern England 
escaped glaciation; . . . and these tracts of the high moor- 
lands in eastern Yorkshire and of the eastern flank of the 
Pennine Chain are similar to the driftless area of southwest- 
ern Wisconsin.” It would seem from Professor Lewis’s facts 
about a moraine in England, as well as from those presently 
to be stated concerning Professor Salisbury’s discoveries in 
northern Germany, that the farthest extent of the ice-front is, 
in Europe as well as in America, considerably in advance of the 
well-defined terminal moraine, and suggests the same difference 
of interpretation as here—i. e., this moraine is either the rem- 
nant of a later glacial period or it is a moraine of retrocession. 


* See also “ American Journal of Science,” vol. cxxxii, 1886, pp. 433-438; 
“Proceedings of the Boston Society of Natural History,” 1887; “Ueber Gla- 
cialerscheinungen bei Gommern unweit Magdeburg” (“ Zeitschr. d. Deutschen 
geolog. Gesellschaft, Jahrg., 1883,” pp. 831-848), and ‘“‘ Mittheilungen ueber 
das Quartaer am Nordrande des Harzes” (ibid., “ Jahrg., 1885,” pp, 897-905), 
von F. Wahnschaffe, in Berlin. 


ES 


_ 


EUROPE DURING THE GLACIAL PERIOD. 453 


The conclusion of Professor Lewis concerning the marine 
shells found at high elevations in glacial deposits on the. 
mountains of Wales, and which have generally been taken to 
indicate a deep submergence during the Glacial epoch or at 
the beginning of the second Glacial epoch, are of the greatest 
importance, and coincide with similar discoveries recently 
announced by Mr. Upham concerning the shells found in the 
vicinity of Boston, and supposed to indicate a post-glacial sub- 
sidence of considerable extent in that vicinity. These shells 
in the British Isles, like those in the vicinity of Boston, are 
mostly in fragments, are very thick and compact in structure, 
and often water-worn and sometimes striated. Their eleva- 
tion in the British Isles reaches as much as thirteen hundred 
and fifty feet above tide. Professor Lewis thinks they 
were plowed up by the glacier as it passed over the trough of 
the Irish Sea, and were elevated to their present position by 
the ice in the same manner that bowlders are seen so often to 
have been elevated in various parts of the United States. I 
again adopt the words of Mr. Upham in his recent comments 
upon this theory : 


The ample descriptions of the shelly drift of these and 
other localities of high levels, and of the lowlands of Cheshire 
and Lancashire, recorded by English geologists, agree per- 
fectly with the explanation given by Lewis, which indeed had 
been before suggested, so long ago as 1874, by Belt and Good- 
child. This removes one of the most perplexing questions 
which glacialists have encountered, for nowhere else in the 
British Isles is there proof of any such submergence during or 
since the Glacial period, the maximum known being five hun- 
dred and ten feet, near Airdrie, in Lanarkshire, Scotland. 
At the same time the submergence on the southern coast 
of England was only from ten to sixty feet, while no traces 
of raised beaches or of Pleistocene marine formations above 
the present sea-level are found in the Orkney and Shetland 
Tslands.* 


= 


American Geologist,” vol. ii, p. 375. 


454 THE ICE AGE IN NORTH AMERICA. 


The work begun by Professor Lewis was subsequently car- 
ried on by The Northwest of England Bowlder Committee, of 
which Professor Perey F. Kendall was for some years the 
efficient chairman. The final conclusion from these and other 
investigations are thus briefly summarized by Dr. F. W. 
Harmer,” as follows: 


“Most glaciologists believe that this country was invaded 
by ice, on the east from the German Ocean, and on the west 
from the Irish Sea. Crossing the Lincolnshire Wolds, ice 
from the North Sea, augmented, I think, by that of an 
inland glacier from the Vale of York, traveled towards the 
plain of the lower Witham and the Fenland, whence it over- 
spread a large tract of country to the east, the south and 
the west. To the east it reached the Suffolk coast, to the 
south nearly to the valley of the Thames, while to the west 
it filled those of the Welland, the Nene, and the Ouse, over- 
riding also the highland intervening. 

“Another branch of the northern glacier, keeping to the 
west of the Lincoln ridge, and reinforced by the North-Sea 
ice, moved towards Doncaster and up the Trent basin to 
- the vicinity of Derbe, where it met the Derwent glacier, and 
thence crept southward along the valley of the Soar into 
Warwickshire. 

“On the west, the Cheshire plain was invaded by ice from 
the Irish Sea which, diverting the glaciers descending from 
the mountains of North Wales towards the south, carried 
vast numbers of Scottish and Lake-District erratics into the 
northern part of the basin of the lower Severn, heaping 
them also upon Cannock Chase, and upon the high land near 
Wolverhampton. 

“In South Wales, Dr. Strahan and his colleagues have 
shown that ice descended in great thickness from the Breck- 
nock Beacons towards the Bristol Channel, reaching the 
shores of the latter near Swansea, filling the Neath and Taff 
valleys to overflowing, and rising to a great height on the 
intervening hills. | 


*“Quarterly Journal of the Geological Society” for November 1907, 
vol. Ixiii, p. 471-474. 


EUROPE DURING THE GLACIAL PERIOD. 455 


‘Evidence has also been found of the invasion of the 
southern part of this district by ice from the Irish Sea, 
which is supposed to have traveled up the Bristol Channel 
from west to east, and to have crossed the Pembrokeshire 
peninsula from St. David’s Head towards Gower and to the 
neighborhood of Cardiff: erratics believed to have been de- 
rived from the first-named locality have been found nearly 
100 miles to the eastward of their probable source. 

“The depth of St. George’s Channel between St. David’s 
Head and Ireland, however, exceeds 50 fathoms, and the 
natural course of the Irish-Sea glacier, joined by those 
descending the western slopes of the Welsh mountains, 
should have beer southward along the great submarine 
valley opening out to the Atlantic. The distribution of the 
erratics just mentioned seems therefore to indicate that the 
volume of ice, approaching the narrowest part of St. George’s 
Channel, was too great to enable it wholly to escape in that 
direction, some of it being forced by lateral pressure to travel 
eastward up the Bristol Channel. 

“Tt seems worth considering whether so important an ice- 
stream would not have blocked the entrance to the estuary 
of the Severn, the result being an accumulation of sedentary 
ice in the valley of that river, derived partly from the glaciers 
of central Wales and partly from Atlantic blizzards, which 
may have prevailed at that epoch. 

“This. view may possibly throw light on the origin of the 
great alluvial and lake-like plain of Glastonbury, and of the 
gorge at Clifton . . . It may explain also why Arenig 
boulders have been piled up on the Clent Hills, southwest 
of Birmingham, to a height of nearly 900 feet. It is difficult 
to understand that this could have occurred, if at that time 
the Welsh ice could have followed an unobstructed course 
along low ground towards the Bristol Channel. 

“The conditions here sketched out, namely, of ice moving 
upon central England from the sea in a direction opposed 
to that of the natural drainage, are precisely those under 
which glacial lakes with their accompanying over-flow chan- 
nels would have naturally originated.” 


456 THE ICE AGE IN NORTH AMERICA. 


During the summer of 1888 Professor Salisbury, who 
had been for several years associated with President Cham- 
berlin in the glacial survey of the Northwestern States and 
Territories, made also a hasty survey of northern Germany 
for the purpose of correlating the glacial deposits of that 
country with those in America. The results were most im- 
portant and interesting.* He found a double series of termi- 
nal moraines back some distance from the extreme glaciated 
limits, as in the Northwestern States of America, and resem- 
bling them both in their composition and in their situation 
with reference to the marginal deposits. As traced by Pro- 
fessor Salisbury, this belt of moraines follows approximately 
the curve of the south shore of the Baltic Sea, and not many 
miles from it. Its course lies through Schleswig-Holstein, 
Mecklenburg, Potsdam (about forty miles north of Berlin), 
thence swinging more to the north, and following nearly the 
line between Pomerania and West Prussia, crossing the Vis- 
tula about twenty miles south of Dantzic, thence easterly to 
the Spirding See, near the boundary of Poland. 

Among the places where this moraine can be best seen 
are—“1. In Province Holstein, the region about (especially 
north of) Eutin; 2. Province Mecklenburg, north of Crivitz, 
and between Biitow and Krépelin ; 3. Province Brandenburg, 
south of Reckatel, between Strassen and Birenbusch, south 
of Furstenberg and north of Everswalde, and between Pyritz 
and Solden; 4. Province Posen, east of Locknitz, and at 
numerous points to the south, and especially about Falkenburg, 
and between Lompelburg and Birwalde. This is one of the 
best localities. 5. Province West Preussen, east of Biitow ; 
6. Province Ost Preussen, between Horn and Widikin.” 

Comparing these with the moraines of America, Professor 
Salisbury remarks : 


In its composition from several members, in its variety of 
development, in its topographic relations, in its topography, in 


* Professor R. D. Salisbury on “Terminal Moraines in Northern Germany,” 
in “ American Journal of Science,” vol. exxxv, 1888, pp. 405, 406. 


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458 THE ICE AGE IN NORTH AMERICA. 


its constitution, in its associated deposits, and in its wide sep- 
aration from the outermost drift limit, this morainic belt cor- 
responds to the extensive morainic belt of America, which 
_extends from Dakota to the Atlantic Ocean. That the one 
formation corresponds to the other does not admit of doubt. 
‘In all essential characteristics they are identical in character. 
What may be their relations in time remains to be determined. 


Fie. 124—Contorted drift of the Cromer ridge; the termina] moraine of the North Sea ice. 


The glaciated areas of the Pyrenees and the Alps are inde- 
pendent of that covered by Scandanavian ice. In France, 
small glaciers were to be found in the higher portions of the 

Auvergne, of the Morvan, of the Vosges, and of the Cevennes; 
while from the Pryenees, glaciers extended northward through- 
out nearly their whole extent. The ice-stream descending 
from the central mass of Mt. Maladetta through the upper 
valley of the Garonne, was joined by several tributaries, and 
attained a length of about forty-five miles. 


EUROPE DURING THE GLACIAL PERIOD. 459 


The Alpine glaciers were much more extensive, filling the 
whole valley between them and the Jura Mountains, and push- 
ing up upon them to their summits. Eastward they deployed 
in the valley of the Rhine as far as Strassburg, and westward 
into the valley of the Rhone as far as Lyons, while southward 
they extended nearly to Turin and Verona in the valley of the 
Po. The accompanying map of Professor Penck shows their 
full extension eastward into Austria and the three successive 
epochs which he names the Wtrm, the Riss, and the Mindel, 
after the three rivers in which the several deposits were most 
typically preserved. ‘These correspond to the Wisconsin, 
the Illinoisan and the Kansan episodes in America, and were 
readily recognized as such by Mr. Leverett. For its bearing 
on later theorizing, it is worthy of notice that these several | 
borders are closely parallel to each other and not separated 
by any great distance. 


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CHAPTER XIX. 
THE CAUSE OF THE GLACIAL PERIOD, 


For the past few years speculation concerning the cause 
of the Glacial period has been largely dominated by an 
astronomical theory. But geologists have in general felt the 
impropriety, in such an important matter, of abandoning 
their own field to accept the glittering results of celestial 
mathematics. At any rate, it would be improper for them 
to let the astronomical solution go unchallenged. If the 
geologist suffers himself to be lifted into the air, like the 
fabled Antzeus, he labors at a disadvantage, and can be easily 
overcome. For this reason the glacialists of America have, 
of late, limited their labors chiefly to the collection of ter- 
restrial facts, and when asked, as they often are, “‘ What was 
the cause of the Glacial period?” the first answer has fre- 
quently been, “That is none of our business.” Still, it is by 
the interpretation of facts that causes are discovered, and the 
collection of facts concerning the glaciation of North America 
has advanced so rapidly during the past few years, that it is 
now high time to consider more fully their meaning and 
discuss the subject anew, if for no other reason than for the 
sake of finding out how little is known about it. 

It is easily seen that a glacier is the combined product of 
eold and moisture. A simple lowering of the temperature 
will not produce an ice age. Before an area can maintain a 
glacier, it must first get the clouds to drop down a sufficient 
amount of snow upon it. A climate which is cold and dry 
may not be so favorable to the production of glaciers as one 
which is temperate, but whose climatic conditions are such 


462 THE ICE AGE IN NORTH AMERICA. 


that there is a large snow-fall. For example, on the steppes 
of Asia, and over the Rocky Mountain plateau of our Western 
States and Territories, the average temperature is low enough 
to permit the formation of extensive glaciers, but the snow- 
fall is so light that even the short summers in high latitudes 
cause it all to disappear ; whereas, on the southwestern coast 
of South America, and in southeastern Alaska, where the 
temperature is moderate, but the snow-fall is large, great 
glaciers push down to the sea even in low latitudes. 

The circumstances, then, pre-eminently favoring the pro- 
duction of glaciers, are abundance of moisture in the atmos- 
phere, and climatic conditions favorable to the precipitation 
of this moisture as snow rather than as rain. Heavy rains 
produce floods, which ,speedily transport the water to the 
ocean-level ; but heavy snows lock up, as it were, the capital 
upon dry land, where, like all other capital, it becomes con- 
servative, and resists with great tenacity both the action of 
gravity and of heat. Under the action of gravity glaciers 
move, indeed, but they move very slowly. Under the influ- 
ence of heat ice melts, but in melting it consumes an enor- 
mous amount of force. 


In order to melt one cubic foot of ice, as much heat is re- 
quired as would heat a cubic foot of water from the freezing- 
point to 176° Fahr., or two cubic feet to 88° Fahr. To melta 
layer of ice a foot thick will therefore use up as much heat as 
would raise a layer of water two feet thick to the temperature 
of 88° Fahr. ; and the effect becomes still more easily under- 
stood if we estimate it as applied to air, for to melt a layer of 
ice only one and a half inch thick would require as much heat 
as would raise a stratum of air eight hundred feet thick from 
the freezing-point to the tropical heat of 88° Fahr. We thus 
obtain a good idea, both of the wonderful power of snow and 
ice in keeping down temperature, and also the reason why it 
takes so long a time to melt away, and is able to go on accu- 
mulating to such an extent as to become permanent. These 
properties would, however, be of no avail if it were liquid, 
like water ; hence it is the state of solidity and almost complete 


ee ee A ie Aaa a as ey lig ii, Se Terre = em le 


THE CAUSE OF THE GLACIAL PERIOD. 463 


immobility of ice that enables it to produce by its accumula- 
tion such extraordinary effects in physical geography and in 
climate as we see in the glaciers of Switzerland, and the ice- 
capped interior of Greenland. * 
- Theories respecting the causes of the glacial period alto- 
gether number more than half a score, principal of which are 
the following: 1. A decrease in the original heat of the planet; 
2. The shifting of the polar axis; 3. A former period of 
greater moisture in the atmosphere; 4. The depletion of 
carbon dioxide in the atmosphere by chemical union and 
oceanic absorption; 5. Variations in the temperature of 
space; 6. Variations in the amount of heat radiated by the 
sun; 7. The combined effect of the precession of the equinoxes 
and of the changing eccentricity of the earth’s orbit; 8. 
‘Changes in the distribution of land and water; 9. Elevation 
of the lands in northern Europe and America to a higher level 
than that now occupied. 
Though these causes cannot in all cases, and perhaps not in 
any case, be supposed to act except in combination with one 
another, it will be profitable to consider them separately. | 
lf, according to the first theory, the Glacial period was 
due to a decrease of the original heat of the planet, the period 
should not have culminated in the past, but we should still 
be looking for its culmination in the future; for both the 
earth and the sun are cooling off. We ay, therefore, drop 
out the first theory. 

If, according to the second theory, the cause had been the 
shifting of the earth’s axis of rotation, we should not find, as 
we now do, evidences that the warm climate which preceded 
the Glacial period approached the poles along the present 
circles of latitude; but, as it is, we find that the temperate 
flora which covered the arctic regions at the close of the 
Tertiary period approached the pole not only in Greenland 
and British America, but also in Spitzbergen and Nova 


* Wallace’s “ Island Life,” pp. 127, 128. 


464 THE ICE AGE IN NORTH AMERICA. 


Zembla. We may, therefore, drop this second theory out of 
consideration. 

The third theory, so ably advocated by Professor Whitney, 
that the Ice age was the direct result of the excessive moisture 
of earlier periods, and that the disappearance of glaciers is to 
be accounted for by a general drying up of the earth, is ruled 
out by the fact that there is evidence, among other things, 
from the vast deposits of salt existing in numerous parts of 


the world, that the work of desiccation has been going on in © 


some portions of the earth from the earliest geological ages. 
For example, central New York is, at the present time, one 
of the best-watered portions of the world; but it is underlaid 
by deposits of salt sixty or seventy feet in thickness, and these 
extend under much of the area of Upper Canada and Michi- 
gan. To produce this amount of salt there must have oc- 
curred, during the Upper Silurian age, the drying up of an 
inland sea over that region a mile in depth. We are com- 
pelled, therefore, to regard the era of the saline group of 
rocks, rather than the present, as the great age of desiccation. 
Besides, moisture in the atmosphere is efficient as a glacial 
cause only when it is precipitated as snow, and this must be 
determined by general meteorological conditions. There is 
probably moisture enough always in the air to produce an 
ice age if the conditions can be combined to precipitate it in 
the right form and at the right place to encourage the growth 
of glaciers. 

The fourth theory is that argued at great length by Profes- 
sors Chamberlin andSalisbury (‘‘Geology,” vol. ii, 665, vol. iii, 
432). According to this theory the presence of an excessive 
amount of carbon dioxide in the atmosphere increases the 
warmth of the earth’s surface by reducing the radiation. 
Therefore, whatever reduces the carbon dioxide in the envel- 
oping atmosphere of the earth will reduce its superficial 
temperature. It is well known that preceding the glacial 
epochs of the permian and pliocene periods there was a great 
extension of land areas on both continents accompanied by 
the formation of great mountain systems. This greatly in- 


a —- 


~iek 


THE CAUSE OF THE GLACIAL PERIOD. 465 


creased the absorption of carbonic dioxide from the atmos- 
phere, through the growth of vegetable and animal life. 
This is shown by the coal and lignite deposits, and by the 
vast beds of limestone and other carbonates. Through this 
means it is suggested, the temperature of the whole earth 
was so lowered that glaciers began to form in the higher lati- 
tudes and on the higher mountains. Coincident with this 
general lowering of temperature the water of the ocean, 
especially in the higher latitudes, would begin to absorb a 
greater proportion of the carbon dioxide and carry it down. 

The theory in full is much more complicated than this, 
and loses its value largely from this fact. But the most 
obvious objection to it is that the operation of the forces in- 
volved must be so slow that it could not fit into the rapid 
succession of events which crowded in upon one another 
during the last glacial period, which was characterized by 
numerous episodes of advance and recession of the ice-sheet 
and all within a very limited period even as geologists reckon 
time. 

The fifth theory and the sixth naturally go together. 
That there may be variations in the temperature of space is 
entirely within the realm of possibility, and that the sun 
may be a variable star is a statement which can not be proved 
absolutely false. Indeed, the hypothesis that the heat of the 
sun is kept up by a bombardment of meteoroids is defended 
by eminent astronomers. In case this were true, a known 
natural cause for the production of variability is certainly in 
the field, since the cometary bodies, which are circulating 
irregularly through space, are probably themselves but ganglia 
of meteoroids which may readily get entangled within the 
predominant sphere of the sun’s attraction, and become a 
means of increasing for a long period the amount of the sun’s 
heat. This theory can not be positively affirmed to be true; 
but, as long as it can not be disproved by astronomical con- 
siderations, it remains in the field to diminish the confidence 
with which we support other hypotheses. 


466 THE ICE AGE IN NORTH AMERICA. 


‘The seventh theory mentioned had in Mr. Croll and in Mr.. 


James Geikie most able and convincing advocates, and for 
many years was generally accepted as sufficient and satisfac- 
tory. Briefly stated, the theory is this: 

As is well known, the earth’s orbit is not a circle, but an 
ellipse, whose longer diameter at the present time exceeds 


its shorter by about 3,000,000 miles. ‘The sun is not in the | 


center, but is, in one of the foci of the ellipse, which at the 
present is about 1,500,000 miles outside of the center. As 
matters are now situated, therefore, the earth on the 21st of 
June (when it is said to be in aphelion) is 3,000,000 miles 
farther from the sun than it is on the 21st of December 
(when it is said to be in perihelion); that is, during the pres- 
ent winters of the northern hemisphere we are 3,000,000 
miles nearer the sun than we are during the summers. 


SP} 


Fie. 125—Exaggerated view of the earth’s orbit, showing the effects of precession of the 
equinoxes. A, condition of things now ; B, as it will be 10.500 years from now. 
But, if a line be drawn through the earth’s orbit joining 

the equinoxes—that is, the points passed through on the 20th 

of March and the 22d of September—we shall find that the 
winter is shorter than the summer. The period from the 
20th of March to the 22d of September, which constitutes 
the summer, is one hundred and eighty-six days, while that 


} 
i 


THE CAUSE OF THE GLACIAL PERIOD. 467 


from September 22d to March 20th is only one hundred and 
seventy-nine days, or seven days less. So that, while the 
earth is farther away from the sun during the summer, and 
receiving daily less heat, the additional seven days occupied 
by that part of the journey makes ample compensation, and 
the absolute amount of heat received during the longer time 
exactly equals that received by the earth during the shorter 
half of its journey. It will be observed, also, that when the 
summer in the northern hemisphere occurs at aphelion, the 
summer in the southern hemisphere occurs in perihelion, thus 
exactly reversing the conditions. 

Now it is claimed by Mr. Croll and others that when, in 
either hemisphere, the winter is short and occurs in perihelion, 
the climate of that hemisphere will be less favorable to the 
production of glaciers than in the hemisphere where the 
winter is long and in aphelion. Consequently, according to 
their theory, the situation of the earth is now favorable to the 
production of glaciers in the southern hemisphere, and un- 
favorable to their production in the northern. This theory 
is not based, however, on the idea that the hemisphere whose 
winter is in aphelion receives less heat from the sun than the 
other hemisphere during that season, but upon the supposition 
that the greater period occupied by the sun in passing through 
aphelion when the winter nights are long, gives more oppor- 
tunity for the loss of heat during winter in that hemisphere 
by radiation. 

Now, if it be correct that a winter in aphelion is favorable 
to glaciation, and a winter in perihelion unfavorable, then, 
from the astronomical changes which transfer this condition 
periodically from one hemisphere to another, we can reason 
that the northern and southern hemispheres are alternately 
subjected to conditions favorable to glaciation. For, through 
what is called the “ precession of the equinoxes,” the periods 
of aphelion and perihelion are exactly reversed in their rela- 
tions to the two hemispheres every 10,500 years. The points 
at which the equinoxes occur are slowly slipping around, 
making a revolution once in about 21,000 years; so that, 


468 THE ICE AGE IN NORTH AMERICA. 


10,500 years from the present time, the winter in the north- 
ern hemisphere will occur in aphelion instead of perihelion ; 
and, if the supposition be correct concerning the influence of 
this increased length of the winter and distance of the earth 
from the sun, the conditions would favor the return of a 
glacial period 10,000 or 11,000 years hence, and would imply 
that similar favorable conditions existed 10,000 or 11,000 
years ago. According to this theory, also, there should have 
been a succession of glacial periods every 21,000 years during 
long ages past. 

But there is still another periodicity in the movements of 
the earth about the sun with which to combine the preced- 
ing. The shape of the earth’s orbit is not permanent, but 
through the influence of the attraction of the planets upon it 
is subject to periodic changes. In astronomical terms, the 
“eccentricity ” of the earth’s orbit is subject to variations ; 
that is, there are sometimes very much greater differences 
than at present between the longer and the shorter diameters 
of the earth’s orbit. When this difference is greatest it 
amounts to no less than 7,000,000 miles; so that at certain 
times the earth is 14,000,000 miles farther from the sun in 
winter than in summer, and wice versa. At the time of 
greatest eccentricity, also, the difference in length between 
the summers and winters would amount to thirty-six days, 
instead of seven or eight as now. 

These periods of greatest eccentricity in the earth’s orbit 
during which, on Mr. Croll’s theory, the conditions were ex- 
tremely favorable for the production of glacial epochs, are 
somewhat unevenly distributed. One of them culminated 
200,000 years ago; another, 750,000; another, 850,000 ; 
another, 2,500,000 ; and another, 2,600,000. In the future 
they will occur 500,000, 800,000, 900,000 hence. In the 
present condition of the earth’s orbit this supposed cause is 
at its minimum. } 

Of the astronomical changes affecting the eccentricity of 
the earth’s orbit, we are certain. But the value of Croll’s 
theory depends upon the correctness of the original assump- — 


THE CAUSE OF THE GLACIAL PERIOD. 469 


tion, that when the winters occur in aphelion there will be a 
great increase of snow-fall and a marked lowering of tem- 
perature during the winter; and that, during the summers, 
heat would have less than its average influence in removing 
the snows of the previous winter. As already remarked, 
however, it should be noted that Mr. Croll’s calculations 
upon these two points do not rest upon any difference in the 
estimate of the absolute amount of heat received during 
these periods. But he assumes that an excessive amount of 
heat would be lost from the earth by radiation during the long 
winters in aphelion; so that the effect from that cause, when 
accumulated during a number of centuries, would be marked 
by a noticeable increase in the glacial fields of the hemisphere 
whose winter was in aphelion, and this would be connected 
with the decrease of glaciers in the other hemisphere, whose 
winters were correspondingly short and in perihelion. 

Having got glaciation started in one hemisphere during 
periods when the winters were in aphelion, Mr. Croll ad- 
duces an additional cause to help on tie refrigeration, in the 
effect which this cause itself would have upon the winds and 
the ocean-currents. He estimates that the heat conveyed by 
the Gulf Stream into the Atlantic Ocean is equal to one 
fifth of all the heat possessed by the waters of the North 
Atlantic; or to the heat received from the sun upon a mill- 
ion and a half square miles at the equator, or two million 
square miles in the temperate zone. “ The stoppage of the 
Gulf Stream would deprive the Atlantic of 77,479,650,000,- 
000,000,000 foot-pounds of energy in the form of heat per 
day.” The cause of the Gulf Stream, therefore, becomes a 
most important element in the problem. What is the force 
driving onward this immense body of warm water, which he 
estimates “to be equal to that of a stream fifty miles broad, 
a thousand feet deep, flowing at the rate of four miles an 
hour,” and whose temperature as it emerges from the Straits 
of Florida averages as high as 65° Fahr., twenty-five degrees 
of which is eventually parted with to ameliorate the climate 
of the North Atlantic ? 


470 THE ICE AGE IN NORTH AMERICA. 


_ With great cogency of reasoning, Mr. Croll shows that 
the trade-winds are the predominant cause of the present 
course of the Gulf Stream. After attempting to show the 
failure of all other theories to account for ocean-currents, and 
for the direction of the Gulf Stream in particular, Mr. Croll 
calls attention to the general correspondence between the 
direction of the winds and that of the great currents of the 
ocean, and shows how powerful this agency must be in giv- 
ing motion to the surface of the water, and by constancy of 
action, finally, to the lower strata of water. Now, from 
some cause or other, at the present time the southeast trade- 
winds are considerably stronger than the northeast. As a 
result, the southeast trades sometimes extend as far as latitude 
10° or 15° north of the equator; while the northeast trades 
rarely extend even as far south as the equator.* The geo- 


a 
6 


SS 


Fic. 126.—Map showing course of currents in the Atlantic Ocean. 6 and 0’ are currents 
set in motion by opposite trade winds ; meeting they produce the equatorial current 


which divides into c and c’ continuing on as a and @’ and e. 


* Croll’s ‘Climate and Time,” p. 70. 


te 


- 
mene 


Se 
eee. 
X\ 


co \ 
iq 
— 


2 
=) el 
< 


VA 
Wa fa} 


fh AY we 
oS 
AY 


Au 


Ww 
: 


\ UX 
e\\ 
+ \\\" 


Fic. 127.—July isobars and prevailing winds. The dotted lines inclose areas with pressure above thirty inches. 


The heavy lines inclose 


areas with pressure below thirty inches. 


472 THE ICE AGE IN NORTH AMERICA, 


graphical position and contour of South America give special] 
significance to this cause in its relation to the Gulf Stream 
and to all the regions dependent on it for warmth of climate. 

Cape St. Roque, the easternmost point of South America, 
is only five degrees south of the equator, and is fifty degrees, 
or three thousand miles, east of the longitude of: Florida. 
With the present relation of the trade-winds to each other, 
this situation of the continent of South America is favorable 
to the production of the Gulf Stream. For it is evident at 
a glance that the movement of water caused in the South 
Atlantic by the southeast trades will be at its maximum over 
the tropical belt in the vicinity of Cape St. Roque, and that 
the movement there will be in a general northwest direction. 
Hence there is great significance in the present contour of 
the continent, it being such that there is nothing to impede 
the movement of water once begun by the trade-winds in a 
northwest direction (at least, so much of it as is north of 
Cape St. Roque); but the current thus started must keep 
on its way until! it reaches the cul-de-sac formed by the Gulf 
of Mexico, and from this there is no escape except through 
the passage between the West India Islands and Florida. 
Here we have a deep, strong current, produced by the same 
hydrostatic law which propels the comparatively small stream 
in the hydraulic ram. Or, to draw an illustration from a 
grander spectacle, the movement is like that of the tides 
when passing up through gradually restricted channels. In 
such cases the thin onward movement of the tidal wave over 
a wide space is translated into a narrow but deeper and more 
powerful current up the gradually restricted channel into 
which it is forced; so that, whereas the general height of 
the tidal wave is but two or three feet, it sometimes in re- 
stricted channels, like the Bay of Fundy, rises to the height 
of seventy feet, and the so-called “bore,” characteristic of 
many tidal rivers, like the Orinoco and the Amazon, becomes 
the terror of navigators. Through such a translation of the 
gentle but steady pressure of the southeast trades over the 
wide area of the South Atlantic Ocean, the waters of the 


THE CAUSE OF THE GLACIAL PERIOD. 473 


Gulf Stream are projected through the Straits of Florida with 
a force sufficient to carry them across the Atlantic and to the 
shores of Iceland and Norway. So far Mr. Croll’s explica- 
tion is certainly very plausible, and seems to proceed from 
well-known physical principles, and is pretty generally ac- 
cepted by scientific men. 

This, however, is only the first step in his argument. 
Another glance at the map will show that if from any cause 
the relations of the trade-winds should be reversed, so that 
the northeast trades should predominate over the southeast, 
and extend some degrees south of the equator, then Cape St. 
Roque would intercept the movement caused by the south- 
east trades, and the warm water from the South Atlantic, 
which is now forced into the Caribbean Sea, would all of it 
_ do what part of it now does, namely, turn to the south, and, 
after following for a while the southwestern trend of the 
South American coast, would join the slow-moving whirlpool 
of the South Atlantic, whose center is on the parallel joining 
Montevideo and Cape Colony. It will thus appear that, in 
searching for the cause of the Gulf Stream, we are ultimately 
compelled to search for the cause of the present preponder- 
ance of the southeast trades in the Atlantic Ocean. This 
sends us backward upon a receding series of causes. 

The southeast trades preponderate because the southern 
hemisphere is cooler than the northern hemisphere, for wind 
is but the movement of the cooler and therefore heavier at- 
mosphere of one region toward a partial vacuum produced 
by a superior degree of heat in another. This conclusion 
pushes us back one step further to find the cause for the 
present lower relative temperature of the southern hemi- 
sphere, and here we strike what is probably a cozneidence, 
but which Mr. Croll and his followers have too readily ac- 
cepted as acause. Mr. Croll thinks he finds the cause of 
the low temperature of the southern hemisphere in the pres- 
ent prevalence there, in moderate degree, of the astronomical 
conditions to which he has attributed the production of gla- 
cial periods. The winters of the southern hemisphere now 


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VEST SAS 


THE CAUSE OF THE GLACIAL PERIOD. 475 


occur in aphelion—that is, when the earth is farthest away 
from the sun, and are seven days longer than the summers. 
While admitting that there is not as yet enough known about 
the laws governing the absorption and retention of the sun’s 
heat upon the earth’s surface to permit us to say with confi- 
dence that the acknowledged glacial condition of the southern 
hemisphere is not produced by the astronomical cause under 
consideration, it must be added that we are also unable to 
prove the inadequacy of other causes to produce the same 
results. In assuming the reality of Mr. Croll’s cause, we are 
in danger of resting on a theoretical may be rather than on 
well-established premises. At any rate, Woeikoff, in the 
ablest review that has yet appeared upon the subject, thinks 
the glaciation of the southern hemisphere may readily enough 
be accounted for without the aid of Croll’s theory, and sums 
up the case thus: 


The extent and depth of the oceans of the southern hemi- 
sphere give a greater steadiness and force to the winds of that 
hemisphere, and the difference is even more marked if we com- 
pare the westerly winds of middle latitudes rather than the 
trades, though also well seen in the latter. Now, land acts in 
two ways on the trade-winds: it weakens them, first, by the 
increase of friction. But this is not all. The trades, few 
ocean regions excepted, are not strong winds; they are impor- 
tant on account of their extent and steadiness. The gradient 
which causes them is small. Now, in such cases, land, even if 
it is not a continent but only a cluster of small islands, has a 
great influence on trade-winds in causing local gradients which 
may have even an opposite direction to the general gradients, 
thus causing different and even opposing winds. ‘The land- 
and sea-breezes and the monsoons are cases in point. Even 
where the disturbances of the normal ocean gradients are not 
large enough to cause monsoons, we see generally the trades 
oftener interrupted in summer, when they are weaker and when 
local thunder-storms and rains are more frequent on land. 
For the two reasons given, the trades of the southern hemi- 
sphere must be more extensive and stronger than those of the 
northern. 


476 THE ICE AGE IN NORTH AMERICA. 


. The relatively small extent of sea in middle latitudes of the 
northern hemisphere, in comparison with the southern, must 
tend to warm the seas of the former, even if the quantity of 
warm water from the tropical seas reaching them be equal. 
Thus, generally in the middle latitudes the evaporation goes 
on at a higher temperature from the seas of the northern than 
the southern hemisphere. Now, this has a very great influ- 
ence on the resulting precipitations; when the evaporation 
goes on at or near 32°, there is much more probability that the 
resulting precipitation will be snow and not rain, even on low 
lands ; the higher the temperature at which the evaporation 
takes place, the greater must be the height at which snow can 
fall, on account of cooling by expansion. 

Not all cold seas are favorable to glaciation. If they are 
surrounded by land on which the winters have a temperature 
considerably below 32°, they will be covered with ice, and thus 
evaporation will be checked just at the time when it is most 
favorable to snow-fall. The ice of the seas will be covered 
with snow, the temperature of the air over it may be very low, 
but the snow-fall will not be great, and thus the conditions not 
favorable to glaciation. Such is the condition of many seas of 
the northern hemisphere, as the Arctic Ocean north of Siberia, 
the Kara Sea, the bays and inlets north of the North American 
Continent, the Sea of Okhotsk, etc., which are covered with ice 
during many months. These conditions are favorable to cold 
of many months’ duration, but not to a large snow-fall and 
the resulting glaciation. The observations made at many 
points off the coasts of Siberia and the North American Archi- 
pelago have shown that the snow-fall is exceedingly light. The 
seas between 45° and 70° of southern latitnde are deep and not 
surrounded by land, and thus by far not so ice-bound, both on 
account of the absence of very low temperatures favorable to 
the formation of ice, and of the rupture of ice, when formed, 
by winds and currents. * 


Thus it is shown that the depth and relative extent of 
the southern ocean furnish a sufficient cause for its present 
glacial conditions. | 


* “ American Journal of Science,” vol. cxxxi, 1886, pp. 175, 176. 


THE CAUSE OF THE GLACIAL PERIOD. AT7 


As already intimated, the weak point in Mr. Crol!l’s the- 
ory is the general state of uncertainty as to the laws regulat- 
ing the absorption, retention, and distribution of the sun’s 
heat upon the earth. It is evident that the heat upon. which 
the earth is dependent is that of the sun; since, as Professor 
Newcomb has shown, the total amount of heat received from 
the stars is probably not one-millionth part of that received 
from the sun.* Now, as all admit that the annual amount 
of heat received from the sun is not affected by changes 
either in the eccentricity of the earth’s orbit, or in the rela- 
tion of the poles to that eccentricity, it is only the question 
of the retention and distribution of heat with which we have 
to do. And here we come to a most obscure realm of sci- 
entific investigation, where ignorance is still profound. The 
reason why the summit of a mountain is cold is not because 
of lack of heat from the sun, but it arises rather from the 
facility with which the heat is dissipated by radiation. On 
the contrary, the reason why the atmosphere of a greenhouse 
is warmer than that upon the outside is not because it recewes 
more heat, but because it retazns more. The intenser heat- 
rays of the sun readily penetrate the glass cover, while the 
less intense rays of radiated heat from the earth are unable 
to do so inreturn. It is well known, also, that clouds pre- 
vent a frost by checking the radiation from the surface of the 
earth. The laws regulating the influence of the atmosphere 
and the floating particles contained in it, over the retention 
of the sun’s heat in its lower strata, are as yet but little un- 
derstood. There is here an almost unlimited field for inves- 
tigation and discovery. 

And this, as just remarked, is the weak point of Mr. 
Croll’s theory. Everything here depends upon the forces 
which distribute the heat and moisture over the land-sur- 
faces. It is by no means certain that, when the winters of 
the northern hemisphere occur in aphelion, they will be 
colder than now. Whether they would be so or not depends 


* “ American Journal of Science,” vol. cxi, 1876, p. 264; vol. cxxvii, 1884, 
p. 22. 


478 THE ICE AGH IN NORTH AMERICA. 


upon the action of forces whose laws can not now be accurately 


calculated. As Woeikoff goes on to show, there are some very 
singular facts in the distribution of heat over the earth’s sur- 
face—proving that the equator is not so hot as theoretically 
it ought to be, and that the arctic regions are not so cold ; and 


this in places which could not be affected by oceanic currents. - 


For example, at Iquitos, on the Amazon, only three hundred 
feet above tide, three degrees and a half south of the equator, 
and more than a thousand miles from the Atlantic (so that 
ocean-currents can not abstract the heat from its vicinity), 
the mean yearly temperature is but 78° Fahr., while at 
Verkhojansk, in northeast Siberia, which is 67° north of the 
equator, and is situated where it is out of the reach of ocean- 
currents, and where the conditions for the radiation of heat 
are most favorable, and where, indeed, the winter is the 
coldest on the globe (January averaging —56° Fahr.) the 
mean yearly temperature is two degrees and a half above zero; 
so that the difference between the temperature upon the 
equator and that at the coldest point on the sixty-seventh 
parallel is only about 75° Fahr.; whereas, if temperature were 
in proportion to heat received from the sun, the difference 
ought to be 172°. Again, the difference between the actual 
January temperature on the fiftieth parallel and that upon 
the sixtieth is but 20° Fahr., whereas, the quantity of solar 
heat received on the fiftieth parallel during the month of 
January is three times that received upon the sixtieth, and 
the difference in temperature ought to be about 170° Fahr. 
upon any known law in the ease. 


But to be quite sure to get’ beyond the influence of ocean- 
currents, I will take the mean January temperature in the 
strictly continental climate of eastern Siberia, under 120° east. 
According to Ferrel’s tables : 

Under 50° north we have 0° Fahr. 
Under 60° north we have —30° Fahr. 

If the January temperature decreased from 50° to 60° north, 
- according to the hypothesis of Dr. Croll, it should be on the 
60° north —155° Fahr. 


; 
} 
t 
: 
: 


THE CAUSE OF THE GLACIAL PERIOD. 479 


But to be quite sure of taking the most favorable case for 
the hypothesis of Dr. Croll, | take the highest January tem- 
perature on the 50° north in Ferrel’s tables, that is, that on 
20° east =44° Fahr., and the coldest January temperature on 
the 60° north, that is, that of 120° and 130° east, = —30° Fahr. 
Yet in proportion to the quantity of heat received, the mean 
temperature of January on 60° north should be —140° Fahr. 

The following table gives the results of the three cases con- 
sidered : 


ieee TEMPERATURE, 60° N. 
Mean tem- | 


| 


Siok aS ~ | Difference. 
ou° N. =| On the hypothe-, 
sis of Dr-Croll, | Actual 

Mean January temperature of 

MOMHETICIANG.: 5. .)-cc cub ods ce 21°3 — 1479 al 149°6 
Mean January temperature in 

120° EK. (east Siberia)........ Ne — 155°3 —30 125°3 
Mean January temperature of 

warmest meridian 50° N., and 

coldest meridian on 60° N.... 44:0 — 1400 —30 | 110:0* 


These facts, and many others like them, make it evident 
that we understand very little about the laws governing the 
distribution of heat over the surface of the earth. Other 
things besides ocean-currents are active in the matter, and 
some of them must be far more potent than any cause which 
we now clearly discern. We quote again the words of the 
same high authority: 


How can we judge of the change of temperature resulting 
from this or that distance from the sun, even if we knew accu- 
rately the temperature of space, when we do not know the dia- 
thermancy of the atmosphere under different conditions? We 
know only that it is exceedingly different, according to the 
different quantities of carbonic acid and aqueous vapor con- 
tained in it, and in a far higher degree, according to the ab- 
sence or presence in different quantities of suspended liquid 
and solid particles (clouds, dust, smoke, etc.). Thus, when 


* Woeikoff in “ American Journal ef Science,” vol. cxxxi, p. 166. 


480 THE ICE AGE IN NORTH AMERICA. 


we do not know in how far the loss of heat is impeded, even an 
accurate knowledge of the temperature of space would be of 
small use in this matter. I will illustrate this by a homely 
example. Take a room where the fire is extinguished and the 
hearth or stove cold in the evening, and try to guess at the 
temperature the room will have in the morning. If we follow 
the method of Dr. Croll, we should inquire only about the out- 
side temperature, and not about the thickness of the walls, the 
windows, etc. I think that, taking the average construction 
of Russian, English, and Italian houses, if the inside tempera- 
ture was in all three cases 60° in the evening, and the outside 
temperature 20° in Russia, 32° in England, and 45° in Italy, 
the morning temperature in the room would not be very differ- 
ent, and probably even higher in the Russian room, owing to 
its thick walls, double windows, ete. 

Thus it is easy to see that the question how great will be 
the temperature of the air at a given place, say in midwinter, 
when the distance of the sun is greater or less than at present, 
can not be answered, even approximatively, especially in the 
exceedingly crude way it is put by Dr. Croll—that is, without 
distinguishing high and low latitudes, continent and ocean, 
ete. One thing is certain, that such a change will certainly 
have a greater influence on the temperatures in the interior of 
continents than on the oceans and their borders. The caloric 
capacity of water is so great, and the mobility of its particles 
so effectual in resisting a lowering of the surface temperature, 
by the convection currents it causes, that I doubt very much 
if, during a great eccentricity and winter in aphelion, the sur- 
face temperature of the oceans can be lower in winter than 
now ; the difference in the quantity of sun-heat is too small 
and too short-continued to give an appreciable difference in 
winter ; and, as in the year there is no difference in the quan- 
tity of heat received by the waters, I think there will be no 
difference in the temperature of the waters, and thus no influ- 
ence of great eccentricity with winter in aphelion on the ocean 
temperatures, and also no greater snow-fall than now. As to 
the continents, I admit that, though we are wnabdle to calculate 
the rate of decrease of temperature of the winter months in these 
conditions, there is no doubt that ¢¢ will be appreciable, and be 


THE CAUSE OF THE GLACIAL PERIOD. 481 


the greater the less a given place is under the influence of the 
seas. * 


We may test the theory still further by an appeal to geo- 
logical facts. According to Mr. Croll, there must have been 
a succession of glacial periods in the past, and it would seem 
that numerous indications of such. epochs, if they occurred, 
must exist in the successive geological strata. If such indi- 
cations are not found in requisite amount, the advocates of 
Mr. Croll’s theory are bound to give a satisfactory explana- 
tion of the failure. 

To a consideration of this evidence Mr. Croll devotes the 
seventeenth and eighteenth chapters of his book on “ Climate 
and Time,” and at the outset confesses that “ the facts which 
have been recorded as evidence in favor of the action of ice 
in former geological epochs are very scanty indeed.” To ac-. 
count for this deficiency of evidence, he adduces, first, “ the 
imperfection of the geological records themselves; and, sec- 
ond, the little attention hitherto paid toward researches of 
this kind.” | 

Mr. Croll’s presentation of the reasons, from the nature 
of the case, why the evidence of glaciation in the earlier geo- 
logical periods should be in large degree obliterated, is prob- 
ably as strong as can be made. He argues that the present 
land-surfaces in nearly all cases represent former ocean-beds, 
hence sedimentary strata deposited during the Glacial age 
must consist of the water-worn material which had been car- 
ried out from glacial streams into the bordering seas and 
oceans, so that the most distinct signs of glacial action which 
we could expect to find in sedimentary strata would be de- 
posits of pebbles, forming conglomerate rocks, and the oceur- 
rence in these conglomerates of occasional angular fragments, 
such as could only be transported on ice. 

Mr. Croll, also, very naturally, dwells upon the extent to 
which the land-surfaces exposed between two geological 
epochs must have suffered from denudation. Erosive agen- 


* Woeikoff in “ American Journal of Science,” vol. cxxxi, pp. 169, 172. 


482 THE ICE AGH IN NORTH AMERICA. 


cies would operate in the ordinary way during the whole 
period of elevation, the streams carrying down to the sea a 
large amount of material everyseason. But when the period 
of depression had proceeded so far as to bring the surface 
below the level of the sea, Mr. Croll believes the action of 
the waves would greatly hasten the operation, and would 
thoroughly sort out and roll the pebbles, washing the finer 
particles into deeper water. 

A careful consideration of the forces in operation, how- 
ever, does not seem wholly to justify this reasoning of Mr. 
Croll. In the first place, there must have been at various 
geological epochs, over the area now most studied, extensive 
land exposures, continuing through a long period of time. 
The Tertiary deposits contain many vegetable remains as 
well as animal, showing the existence of land areas of no 
small extent. The Carboniferous period reveals whole con- 
tinents maintaining, over a large portion of their extent, an 
elevation near the sea-level, in which there were continual 
but slight oscillations, tending, however, on the whole to 
subsidence. So that land-plants accumulated in sufficient 
quantity to form the coal-beds—the periods of depression 
being marked by sedimentary rocks formed by the consolida- 
tion of the wash that was spread over the whole region dur- 
ing the times of depression. 

Now, it does not seem possible that a glaciated area so ex- 
tensive as is that of North America, and so deeply covered 
with glacial débris, could be so completely removed by or- 
dinary denuding agencies that no more signs of it should 
appear than are found of such phenomena in the earlier geo- 
logical epochs; for the till, or ground-moraine, is not readily 
removed' by the action of water, even where subjected to the 
shore-waves of the ocean. The bowlders which are washed 
out of it form a protecting barricade around the base of the 
deposit, so that islands like those in Boston Harbor, com- 
posed wholly of till, are as nearly proof against the waves as 
are those of ordinary rocks. If there were in progress a sub- 
sidence of the glaciated area of North America, instead of 


THE CAUSE OF THE GLACIAL PERIOD. 483 


having the waves wash the glaciated surfaces away gradually 
from the edges inward, we should find merely an encroaci- 
ment made here and there upon the border during a portion 
of the subsidence, until, finally, when the waters covered the 
whole, all but a very thin stratum of the upper portion would 
be protected from further disturbance. Especially must the 
till remain in the innumerable buried channels of the glaci- 
ated region, and over the extensive protected northern slopes. 
It is thus difficult to conceive how there should ever be any 
such complete removal of the ground-moraine from the im- 
mense glaciated area of North America as Mr. Croll sup- 
poses to have occurred several times over in preceding gla- 
cial epochs. 

The facts supposed to prove, by direct evidence, the ex- 
istence of glacial periods in the various successive geological 
epochs, can be briefly stated.* 

Beginning with some of the oldest sedimentary strata, 
Professor Archibald Geikie has discovered what he believes 
to be unmistakable signs of glacial action in the north of 
Scotland, in Sutherlandshire, on rocks of Cambrian age— 
that is, just below the base of the Silurian system. Here he 
reports extensive surfaces of gneiss rock worn into the char- 
acteristic “rounded bossy surface” of glaciated regions, and 
this evidently runs under an extensive deposit of breccia of 
glacial origin, made up of fragments eroded by ice at that 
early period of glaciation.t Some of the fragments of this 
overlying breccia are said to be from five to six feet long. 

A second instance of early glaciation, mentioned by Pro- 
fessor Ramsay, occurs in the south of Scotland, in Ayrshire 
and Wigtonshire, in the Lower Silurian formations of that 
region. Here are extensive sedimentary rocks, containing 


* On the whole, the best summary of the evidence upon this subject, and the 
one to which we are mainly indebted for the facts here presented, was given by 
Sir A. C. Ramsay, Director-General of the Geological Survey of the United King- 
dom, in his Presidential Address before the British Association of Swansea in 
1880. (See “ Nature,” vol. xxii, p. 388 ef seq.) 

+ See communication to “‘ Nature,” vol. xxii, pp. 400-403. 


484: THE ICE AGE IN NORTH AMERICA. 


characteristic Lower Silurian fossils, in which are numerous 
erratic blocks of gneiss and granite, some of them as many as — 
nine feet in length. Both Dr. Ramsay and Mr. James Geikie — 
believe that the nearest source from which these fragments 
could come is one hundred miles or more to the north. Their 
theory is that, in the eariy Silurian times, the region oceu- 
pied by the Hebrides and the adjoining coast of northern 
Scotland consisted of an immense granitic mountain uplift, 
down which glaciers descended to the sea, sending off bowlder- 
laden icebergs, which wandered to the vicinity of Ayrshire 
and Wigtonshire, and there dropped their burdens. 

In India, also, according to Dr. Ramsay, Medlicott and 
Blanford describe “old slates supposed to be Silurian, con- 
taining bowlders in great numbers,” which these experienced 
authorities believe to be of glacial origin. They also de- 
scribe other very ancient transition beds which overlie rocks 
“marked by distinct glacial striations.” Again, Dr. Ramsay 
describes bowlder-beds in the south of Scotland, on the Lam- 
mermoor Hills, south of Dunbar, which “ contain what seem 
to be indistinctly ice-scratched stones.’ These beds lie “ un- 
conformably on Lower Silurian strata,” and are now gener- 
ally believed by the members of the Geological Survey of 
Scotland to be of glacial origin. Dr. Ramsay goes on to say: 


I know of no bowlder formations in the Carboniferous series, 
but they are well known as occurring on a large scale in the 
Permian brecciated conglomerates, where they consist of peb- 
bles and large blocks of stone, generally angular, imbedded in 
a marly paste; . . . the fragments have mostly traveled from 
a distance, apparently from the borders of Wales, and some of 
them are three feet in diameter. Some of the stones are as 
well scratched as those found in modern moraines or in the 
ordinary bowlder-clay of what is commonly called the Glacial 
epoch. In 1855 the old idea was still not unprevalent that 
during the Permian epoch, and for long after, the globe had 
not yet cooled sufficiently to allow of the climates of the exter- 
nal world being universally affected by the constant radiation 
of heat from its interior. For a long time, however, this idea 


THE CAUSE OF THE GLACIAL PERIOD. 4895 


has almost entirely vanished, and now, in Britain at all events, 
it is little if at all attended to, and other glacial episodes in the 
history of the world have continued to be brought forward and 
are no longer looked upon as mere ill-judged conjectures, 

The same kind of brecciated bowlder-beds that are found in 
our Permian strata occur in the Rotheliegende of Germany, 
which I have visited in several places, and I believe them to 
have had a like glacial origin. 

Mr. G. W. Stow, of the Orange Free State, has - late years 
given most elaborate accounts of similar Permian bowlder-beds 
in South Africa. There great masses of moraine matter not 
only contain ice-scratched stones, but on the banks of rivers 
where the Permian rock has been removed by aqueous denuda- 
tion the underlying rocks, well rounded and mammillated, are 
covered by deeply incised glacier grooves pointing in a direction 
which at length leads the observer to the pre-Permian mount- 
ains whence the stones were derived that formed these ancient 
moraines. | 

Messrs. Blanford and Medlicott have also given, in ‘“‘ The 
Geology of India,” an account of bowlder-beds in what they 
believe to be Permian strata, and which they compare with 
those described by me in England many years before. There 
the Talchir strata of the Gondwana group contain numerous 
bowlders, many of them six feet in diameter, and in one in- 
stance some of the blocks were found to be polished and striated, 
~ and the underlying Vindhyan rocks were similarly marked. 
The authors also correlate these glacial phenomena with those 
found in similar deposits in South Africa, discovered and de- 
scribed by Mr. Stow. 

In the Olive group of the Salt range, described by the same 
authors, there is a curious resemblance between a certain con- 
glomerate ‘‘and that of the Talchir group of the Gondwana 
system.” This ‘‘ Olive conglomerate” belongs to the Creta- 
ceous series, and contains ice-transported erratic bowlders de- 
rived from unknown rocks, one of which, a red granite, ‘is 
polished and striated on three faces in so characteristic a man- 
ner that very little doubt can exist of its having been trans- 
ported by ice.” One block of red granite at the Mayo salt- 
mines of Khewra ‘‘is seven feet high and nineteen feet in cir- 


486 THE ICH AGE IN NORTH AMERICA. 


cumference.” In the “transition beds” of the same authors, 
which are supposed to be of Upper Cretaceous age, there also 
are bowlder-beds with erratic blocks of great size. 

I know of no evidence of glacial phenomena in Eocene strata 
excepting the occurrence of huge masses of included gneiss in 
the strata known as Flysch in Switzerland. On this question, 
however, Swiss geologists are by no means agreed, and I attach 
little or no importance to it as affording evidence of glacier ice. 

Neither do I know of any Miocene glacier deposits except- 
ing those in the north of Italy, near Turin, described by the 
late eminent geologist, Gastaldi, and which I saw under his 
guidance. ‘These contained many large erratic bowlders de- 
rived from the distant Alps, which, in my opinion, were then 
at least as lofty as or even higher than they are now, especially 
if we consider the immense amount of denudation which they 
underwent during Miocene, later Tertiary, and post-Tertiary 
times. * ; 


In North America Professor Shaler would attribute the 
conglomerates. of Jurassic age in the valley of the Con- 
necticut, in a part of which lie the celebrated bird-tracks, to 
glacial origin.. This he infers, from the great thickness of 
the beds, the absence of life from the accompanying sand- 
stones, the subangular forms of many of the pebbles, and 
from the similarity in composition of the pebbles of that 


conglomerate with that-of those found in the modern drift — 


of the region.t' Upon this conclusion, however, it is proper 
to remark that the drift in the lower Connecticut Valley 
would, to a great extent, come from the same region, whether 
brought by ice or water, and the extent to which the pebbles 
would have been reduced to uniformity and smoothness by 
attrition depends upon the distance to which they have been 
rolled, or the length of time to which they have been sub- 
jected to wave-action. From what appears, the evidence is 
not clear that the fragments from which the pebbles are 


x ON ature,” vol. xxii, p. 389. 
+ See “Illustrations of the Earth’s Surface: Glaciers,” by N. S. Shaler and 
W. M. Davis. Boston: James R. Osgood & Co., 1881, p. 95. 


THE CAUSE OF THE GLACIAL PERIOD. 487 


made may not have originated in the near vicinity, and so 
their subangular condition need not imply glacial agency in 
transportation. 

Professor Shaler also is inclined to attribute the exten- 
sive conglomerate deposits of the Carboniferous age in the 
Appalachian district of North America to glacial action ; 
and certainly the extent of these conglomerate deposits un- 
derlying the coal-beds is surprising. “ In Pennsylvania they 
are about one thousand feet; in eastern Kentucky and east 
Tennessee their thickness rises to about two thousand feet.” 
Similar conglomerate deposits everywhere underlie the Car- 
boniferous system: According to Professor Shaler, ‘* we 


find it from southern France to Scotland, from Alabama to 


New Brunswick, in India, and elsewhere.” For the most 
part, however, the pebbles of this conglomerate consist of 
quartz or quartzite, well rounded, and seldom of larger size 
than can readily be transported by water ; though Professor 
Newberry is reported to have “found a bowlder of quartz- 
ite seventeen inches by twelve inches, imbedded in a seam 
of coal.” Altogether it seems more likely that we have in 
these conglomerates underlying the Appalachian coal-tields 
of America the wash brought down by large rivers heading 
in the mountain plateau toward the north and east, of which 
the Archean range on the Atlantic border, together with the 
hills of New England and the Adirondacks of New York, are 
but the remnants. That floating ice may have played some 
part in the streams coming down from these mountain-heighits 
is not improbable ; but it is doubtful whether the facts war- 
rant us in inferring anything more. 

Professor Shaler would also attribute a still lower series 
of conglomerates whose typical development is in eastern 
Tennessee and western North Carolina, and which rests un- 
conformably upon Laurentian rocks, to glacial action ; though 
he confesses that no scratched bowlders have yet been dis- 
covered in these deposits, but he writes: ‘‘ Recollecting that 
we know of no force that is competent to bring together such 
masses of pebbles derived from a wide-spread surface save 


488 THE ICE AGE IN NORTH AMERICA. 


glacial action, we are justified in believing that this deposit 
is a product of ice-action, though the waste has evidently 
been worked over by water since its production.” The 
thickness of the deposits he estimates to be in some places 
nearly twenty thousand feet. These deposits correspond in 
age to the Roxbury conglomerates in Boston, which are 
about five hundred feet in thickness, and “are composed of 
materials derived from various points in eastern Massachusetts 
and southern New Hampshire. The pebbles are rarely over 
a foot in diameter.” But Professor Shaler thinks “ their 
frequently subangular forms and the wide range of sub- 
stances associated together make it pretty clear that they 
have a glacial origin.” 

Upon this the same remark is applicable which was made 
in a preceding section, namely, that along this whole Appala- 
chian border there were formerly Archean highlands of in- 
definite height, of which the stumps are all that now remain 
in the present hills and mountains. The erosion of these 
mountains on their western flanks has furnished the material 
of the vast sedimentary deposits of the eastern part of the 
Mississippi basin. For all we know, the material spread out 
over this area of sedimentary rocks was all within reach of 
rivers coming down from Archean heights, and so there is 
no necessity of supposing extensive glacial transportation 
from more northern water-sheds such as we are compelled to 
suppose in the glacial age of recent date. The same remark 
may be extended to all the evidence adduced in the preced- 
ing sections concerning a succession of glacial periods.* In 
all cases they are of such limited character that local glaciers 
coming down from isolated mountain-masses, such as now 
come down from the mountains of Alaska, Patagonia, and at 
no very distant date from those of New Zealand, are sufficient 
to account for the facts. 

Returning to the point under discussion, it is proper to 
remark that the conclusions here presented with reference to 


* See Lyell, “ Principles of Geology,” vol. i, pp. 293-210. 


THE CAUSE OF THE GLACIAL PERIOD. 489 


Mr. Croll’s theory are those pretty generally adopted at the 
present time by the American gevlogists best qualified to in- 
terpret the facts. Thus, among the more eminent American 
geologists, Mr. G. K. Gilbert wrote, in 1883: 


It deals with a series of physical laws and physical condi- 
tions which interact upon each other in an exceedingly complex 
way—in so complex a way that meteorologists, who have to 
deal with only a portion of them, do not claim and scarcely 
hope for a complete analysis of their combinations. The op- 
portunities for arguing in a circle are most seductive, and the 
a priori probability that important considerations have been 
overlooked is not small. 

The only manner in which so comprehensive and intricate 
an hypothesis can be established is by stimulating inquiry which 
shall lead to corroborative evidence, and this is precisely what 
Croll’s hypothesis, after eight years of wide publicity, has failed 
todo. If it is true, then epochs of cold must have occurred 
with considerable frequency through the entire period repre- 
sented by the stratified rocks; and iceberg drift, if no other 
traces, should have been entombed at numerous horizons. It 
has not been found, however, and of the eight horizons claimed 
by Croll to show evidence of glacial action, the treatise under 
consideration [A. Geikie’s ‘‘ Text-Book of Geology” ] mentions 
only two with confidence, and two others with doubt. In the 
two instances to which queries are not attached, the phenomena 
appear to indicate local and not general glaciation. If the 
hypothesis is true, the cold of the Glacial epoch must have 
been many times interrupted by intervals of exceptional warmth, 
but little has been added to the evidence adduced by Croll for 
such an interruption, and in America, where there is now great 
activity in the investigation of glacial phenomena, the evidence 
of a single inter-glacial period is cumulative and overwhelming, 
while there is no indication whatever of more than one.* 


With this agrees the opinion of President Chamberlin : 


The various astronomical hypotheses seem to be the worse 
for increased knowledge of the distribution of the ancient ice- 


* “Nature,” vol. xxvii, p. 262. 
) 
dl 


490 THE ICE AGE IN NORTH AMERICA. 


sheet. I think I speak the growing conviction of active work- 
ers in the American field, that even the ingenious theory of 
Croll becomes increasingly unsatisfactory as the phenomena 
are developed into fuller appreciation. I think I may say 
this without prejudice, as one who, at a certain stage of study, 
was greatly drawn toward that fascinating hypothesis. 

But the more we know and ponder upon the enormous de- 
velopment of iceupon the plains of northeastern America, and 
contrast it with the relatively feeble development and disper- 
sion from the mountainous regions of Alaska, which now bear 
the greatest glaciers outside of the arctic regions, and the rela- 
tive absence of such accumulations in northeastern Asia—in 
short, the more we consider the asymmetry of the ice distri- 
bution in latitude and longitude, and its disparity in eleva- 
tion, the more difficult it becomes to explain the phenomena 
upon any astronomical basis, correlated though it be with 
oceanic and aérial currents and geographical features, by 

whatsoever of ingenuity.* 


Professor Le Conte remarks, in similar strain : 


Of the recurrence of many glacial epochs in the history of 
the earth there is as yet no reliable evidence, but much evidence 
to the contrary. It is true that what seem to be glacial drifts, 
with scored bowlders, etc., have been found on several geologi- 
cal horizons, but these are usually in the vicinity of lofty 
mountains, and are probably, therefore, evidence of local glacia- 
tion, not of a glacial epoch. On the other hand, all the evi- 
dence derived from fossils plainly indicates warm climates even 
in polar regions during all geological periods antil the Quater- 
nary. The evidence at present, therefore, is overwhelmingly 
in favor of the wniqueness of the Glacial epoch. This fact is 
the great objection to Croll’s theory. f 


All doubts, concerning the existence of carboniferous and 
cambrian glacial periods have, however, been removed by 
facts which have accumulated during the last twenty-five 


_ *“Proceedings of the American Association for the Advancement of Sci- 
ence,” vol. xxxv, p.211. 
+ “Elements of Geology,” p. 577. 


THE CAUSE OF THE GLACIAL PERIOD. 491 


years. It is now well ascertained that there have been several 
glacial periods but at irregular and widely separated intervals. 
The irregularity of the intervals would indicate that the cause 
cannot be the astronomical changes which Mr. Croll had 
adduced, for they occur at regular intervals. The facts as 
summarized by Professor Coleman are as follows:* 


(1) The Huronian rocks of Canada, which are the oldest 
sedimentary strata in existence, contain extensive conglom- 
erates in every area mapped in northern Canada through a 
region 1,000 miles long from east to west and 750 miles broad. 
Some of the bowlders in this conglomerate are tons in weight, 
while striated pebbles are as characteristic of glacial deposits 
as can be found in any other age. Sir Archibald Geikie had 
also noted similar deposits of archean age in Scotland. The 
deposits in Canada occur over hundreds of thousands of square 
miles. 


(2) In rocks of early cambrian age extensive conglom- 
erates such as would be formed from the petrification of 
glacial till are found in widely scattered regions, more specially 
of the southern hemisphere. From such deposits in China 
Mr. Baily Willis has recently brought back beautifully 
glaciated stones. But much larger areas in Australia and 
South Africa are covered with “‘tillite’’ of cambrian age. In ° 
South Australia Mr. Howchin has traced these deposits over 
an area extending 450 miles from north to south and 250 from 
east to west, with a thickness of 1,500 feet. In South Africa 
the cambrian tillite has been traced by Mr. Rogers over an 
area of 1,000 miles. In both regions the glaciated area lies 
near the 30th degree of latitude, andthemovement of bowlders 
has apparently been from south towards the north. Similar, 
but less clearly defined cambrian tillite has been reported at 
various places about Lake Superior. In Australia the ice 


*“‘Glacial Periods and Their Bearing on the Geological Theories,”’ 
“Bulletin of the Geological Society of America,’’ vol. xix, pp. 347-566. 


492 THE ICE AGE IN NORTH AMERICA. 


movement evidently reached sea-level in regions which now 
have a warm temperate climate. 

There was a glacial epoch of great intensity at the close 
of the carboniferous period, which has been studied with much 
care in India, Australia, South Africa and South America. 
In India bowlder conglomerates or “‘tillite” occur at points 
which are from 700 to 800 miles apart, or if those reported 
from Afghanistan be included, extending from latitude 35° 
to 16°, a distance of 1,500 miles. In Australia this permo- 
carboniferous tillite has been traced ‘‘ widely in all the states 
of the Commonwealth, including the island of Tasmania to 
the south, with a range of latitude between 20° 30’ and 43°. 
Striated rock surfaces are often found under the old bowlder 
clay, the directions of the scorings indicating a motion of the 
ice in general from south to north, as might be expected; but 
in various places the ice-sheet or sheets reached the sea, large 
bowlders occurring in stratified shale, as if dropped from 
ice, and marine fossils being found in close connection with 
the beds containing bowlders.” 

The most remarkable glacial deposits of this age, however, 
or in some respects of any age, are found in South Africa, 
where fully 1,000,000 square miles are covered with tillite 
extending from 30° southeast for a distance of 800 miles. It 
is found in all the provinces “‘from the south of Cape Colony 
to the middle of the Transvaal or possibly the southern boun- 
dary of Rhodesia, and from Priesk, in Cape Colony, on the 
west to eastern Natal.’ The deposit is thin in the north, and 
thick in the south where, in Cape Colony, it reaches a thick- 
ness of 1,000 feet. No striated rock surfaces are found in the 
south, but they abound in the north. The deposits occur at 
elevations of from 3,000 to 6,000 feet above the sea, but along 
the southern margin the deposits were evidently laid down in 
water, whether salt or fresh has not been determined. The 
most surprising thing about these deposits in South Africa is 
that the transportation has been from the equator towards the 


ee ee ee eee A ee ee ce Si Atii aia ease UR Baca Sais UA ay Sas Berean Sear ae ht 


Fic. 129—Glaciated pebble, 7 inches long, from Fie. 130-Glaciated pebble, 11inches 
Lower Huronian, Cobalt, Can. (A. P. Colman.) long, from Dwyka, Matjesfontein, 
CapeColony. (A. P.Colman.) 


Fic. 131—Glaciated pleistocene surface from Lower Huronian tillite near Thessalon, 
Ont. (A. P. Colman.) 


494 THE ICE AGE IN NORTH AMERICA. 


south pole. This was indicated by the fact just mentioned 
that they increased in thickness from north to south, as they 
do in the pleistocene glacial deposits of North America, 
though on different sides of the equator. But more decisive 
evidence appears in the direction of the scratches on the under- 
lying rock, which is from northwest to southeast; and from 
the bowlders which have all been transported in the same 
direction. 

In. India also the ice movement of the permo-carbonif- 
erous period was from the equator northward, toward the 
pole, in some cases bowlders having been transported 750 
miles in that direction. 

Other indications of a permo-carboniferous period have 
been reported by Karpinsky and Tchernyschev in the Ural 
Mountains, and by Ramsay in England, but no one has 
discovered clear evidences of such deposits in America. 

With reference to these deposits it is significantly remarked 
by Professor Coleman that ‘‘as in the pleistocene, there seems 
to have been an impressive grouping of the great ice-sheets 
in a special quarter, this time in the neighborhood of the 


present Indian Ocean; and their nearness to the equator, on 
low ground and reaching to the sea, makes it all the more 
puzzling that so little evidence of glacial work should be 


found in higher latitudes.”’ 


CHAPTER XIX. 
THE CAUSE OF THE GLACIAL PERIOD—CONTINUED. 


The eighth theory, which would attribute the growth and 
disappearance of glaciers entirely to changes in the distribu- © 
tion of land and water over the surface of the globe, was, 
according to his general principles, abiy and ardently advo- 
cated by Sir Charles Lyell; and no one can read in his 
“Principles of Geology” the chapters upon this subject 
without being greatly impressed by the possible influences of 
such changes. The ocean is the great equalizer of the earth’s 
temperature. Through unimpeded ocean-currents, like the 
Gulf Stream of the Altantic and the Kuro-Siwa cf the Pacific, 
the heat of the tropics is transferred many thousands of miles 
to ameliorate the climate of even the polar regions. It is 
quite possible that comparatively slight changes in level in 
the vicinity of the West India Islands and Central America 
might so affect the direction of the Gulf Stream as to produce 
most serious modifications of the climate in North America 
and Europe. Should a portion of the Gulf Stream be driven 
through a depression across the Isthmus of Panama into the 
Pacific, and an equal portion be diverted from the Atlantic 
coast of the United States by an elevation of the sea-bottom 
between Florida and Cuba, the consequences would neces- 
sarily be incalculably great, so that the mere existence ofsuch 
a possible cause for great changes in the distribution of moist- 
ure over the northern hemisphere is sufficient to make one 
hesitate before committing himself unreservedly to any other 
theory—at any rate, to one which has not for itself indepen- 
dent and adequate proof. 


496 THE ICE AGE IN NORTH AMERICA. 


It is profitable, also, in this connection, to reflect on how 
delicately balanced the forces of Nature now are with respect 
to the production of glaciers. As already noted,* the gla- 
ciers existing at the present time in the Alps have their peri- 
ods of advance and recession. A slight increase in the 
present snow-fall of Switzerland, if long continued, would 
produce alarming results. From this cause alone, the 
glaciers would at once begin to enlarge; and, in sympathy, 
the temperature would fall, and the increase of the glaciated 
area of Switzerland would go on until the whole country was 
again brought under the desolating reign of ice, or until the 
intervention of some counteracting force should stay its 
advance. It is not without reason, therefore, that some 
alarm was occasioned in Switzerland a few years ago by the. 
proposition to inundate the Desert of Sahara. Fortunately, 
no extensive inundation of that region is within the reach of 
human power. But, if it could be inundated, thus extend- 
ing greatly the evaporating area from which the clouds 
gather moisture for the Alpine heights, there is no telling 
what the result might not be. Should there be an annual 
increase of a foot of snow upon the Alps, a thousand addi- 
tional feet of snow would have to be dissolved every thou- 
sand years, with the enormous absorption of heat accom- 
panying the process. This simple calculation is sufficient to 
show the reality of the cause introduced by the eighth hy- 
pothesis, which would explain the Glacial period through 
the influence upon climate of changes in the distribution of 
land and water. ‘This cause is so effective that it may even 
be conceived to be sufficient, without the introduction of any 
other agencies. He 

The ninth theory, which introduces considerable change 
of levels .n the continents, rests, without doubt, upon a true 
cause, which, very likely, has coéperated with others, and 
may in itself have been the chief agency in producing the 
glacial conditions which we are studying. ‘The evidence in 
support of this theory was so well presented by Dr. Warren 


*See pagel05. 


THE CAUSE OF THE GLACIAL PERIOD. 497 


Upham, in the appendix to the original edition of this volume 
and his conclusions have been supported by so many lines of 
evidence which have since come to light, that we now insert 
it in the body of the discussion with such supplementary 
notes as he has thought it necessary to add. It is a signifi- 
cant confirmation of his views that Professor Chamberlin’s 
theory of the effect of the diminution of the carbonic dioxide 
in the atmosphere in producing glacial conditions involves 
extensive continental elevation of land surfaces as prelimi- 
nary to the supposed depletion of this important element. 


An examination of the evidence of changes in the relative 
heights of land and sea in various parts of the world during 
Quaternary time has led me to an explanation of the causes of 
theGlacial period, which, in this applicationof its fundamental 
principle, seems to be new, while in its secondary elements 
it combines many of the features of the explanations proposed 
by Lyell and Dana and by Croll. Briefly stated, the condi- 
tion and relation of the earth’s crust and interior appear to be 
such that they produce, in connection with contraction of the 
earth’s mass, depressions and uplifts of extensive areas, some 
of which have been raised to heights where their precipita- 
tion of moisture throughout the year was almost wholly 
snow, gradually forming thick ice-sheets; but under the heavy 
load of ice subsidence ensued, with correlative uplift of other 
portions of the earth’s crust; so that glacial conditions may 
have prevailed alternately in the northern and southern hemis- 
pheres, or in North America and Europe, and may have been 
repeated after warm interglacial epochs. 


Quaternary oscillations of land and sea in glaciated regions 
have been discussed by Croll and Geikie on the assumption 
that the earth was so rigid that its form would not be changed 
‘by the load of the ice-sheet nor by its removal, which seemed 
more probable because of the well-known physical and mathe- 
matical researches of Hopkins, Thomson, Pratt, and Professor 
G. H. Darwin. who conclude that the earth is probably solid, 


498 THE ICE AGE IN NORTH AMERICA, 


with not less rigidity than that of glass or steel. In def- 
erence to their researches, this conclusion is accepted and 
taught in recent text-books of geology by Le Conte and A. 
Geikie ; but in similarly recent text-books Dana and Prestwich 
teach that the earth probably consists of a comparatively thin 
crust underlaid by a molten interior, which may change within 
a moderate depth to a great nucleal solid mass. Among other 
geologists and physicists who have discussed the condition of 
the earth’s interior, King * and Shaler ¢ believe it to be solid ; 
while Whitney,f Dutton,* Powell, || Wadsworth,“ Crosby, } 
Gilbert,{ Claypole, } Airy, t Fisher,** and Jamieson, tt believe 
that it is molten, or, at least, is surrounded by a molten layer, 
and that the earth’s crust floats in a condition of hydrostatic 
equilibrium upon the heavier liquid or viscous mobile interior 
or layer enveloping the interior, subject, however, to strains 
and resulting deformation because of the earth’s contraction. 
The thickness of the crust, according to this hypothesis, is 
variously estimated to be from twenty to fifty miles, or posnieny 
a hundred miles or more. 

It must be confessed that we have only a very inadequate 
knowledge of the conditions which would result from the enor- 


* “United States Geological Exploration of the Fortieth Parallel,” vol. i, 
“Systematic Geology,” 1878, pp. 117, 696-725. 

._t “ Proceedings of the Boston Society of Natural History,” 1866, vol. xi, pp. 
8-15; 1868, vol. xii, pp. 128-136; 1874, vol. xvii, pp. 288-292. ‘Memoirs of 
the Boston Society of Natural History,” 1874, vol. ii, pp. 320-340. “ Seribner’s 
Magazine,” vol. iii, pp. 201-226, February, 1888. 

} “‘ Earthquakes, Volcanoes, and Mountain Building,” 1871, pp. 77-87. 

# “Penn Monthly,” vol. vii, pp. 364-378, and 417-431, May and June, 1876. 
“ United States Geological Survey, Fourth Annual Report, ” pp. 183-198 ; “Sixth 
Annual Report,” pp. 195-198. 

|| “Science,” vol. iii, pp. 480-482, April 18, 1884. 

A “ American Naturalist,” vol. xviii, June, July, and August, 1884. 

) “Proceedings of the Boston Society of Natural History,” 1883, vol. xxii, 
pp. 443-485. ‘Geological Magazine,” II, vol. x, 1883, pp. 241-252. 

} “ American Journal of Science,” III, vol. xxxi, pp. 284-299, April, 1886. 

$ “ American Naturalist,” vol. xix, pp. 257-268, March, 1885. “ American 
Geologist,” vol. i, pp. 382-386, and vol. ii, pp. 28-35, June and July, 1888. 

4 “Nature,” vol. xviii, pp. 41-44, May 9, 1878. 

** “ Physics of the Earth’s Crust,” 1881, pp. 223, 270, ete. 

++ ‘“ Geological Magazine,” III, vol. iv, 1887, pp. 344-348, 


THE CAUSE OF THE GLACIAL PERIOD. 499 


mous pressure and high temperature of the earth’s interior, and 
wide diversity in speculations on this subject will probably long 
continue. Professor Shaler, while holding that the earth is 
mainly solid throughout, perhaps having in its most mobile 
layer beneath the crust ‘‘a rigidity such as belongs to the 
metals of average resistance to compression,” yet is one of the 
earliest and most decided advocates of the opinion that the 
weight of an ice-sheet may depress the area on which it lies, 
and that the departure of the ice would be attended by re- 
elevation. In comparison, however, with the physical condi- 
tions and laws familiar to us upon the earth’s surface, the 
subsidence and elevation of extensive areas, as of nearly all 
glaciated regions, seem to demonstrate a mobility of the earth’s 
interior as if it were fused rock. The same conclusion is in- 
dicated by volcanoes, which are probably the openings of molt- 
en passages that communicate downward through the crust to 
the heavier melted interior, thence deriving their supply of 
heat, while their outpoured lavas consist largely or wholly of 
fused portions of the crust, the phenomena of eruption being 
caused by the access of water to the upper part of the molten 
rock near the volcanic vent. But the great plications of the 
strata in the formation of mountain-chains evidently involve 
only the upper part of the earth’s crust, crumpled into smaller 
area in adapting itself to the diminishing volume of the lower 
portion of the same crust, which, with the nucleus, is under- 
going contraction on account of the gradual loss of its heat, 
and perhaps also on account of progressing solidification and 
compression. There is in this process no dependence on the 
molten condition of the interior, except as that seems to be 
necessary for distortion of the earth, both of the crust and 
nucleus or mobile layer enveloping the nucleus, whereby con- 
siderable shrinkage of volume can take place before the ac- 
cumulated strain becomes sufficient for the formation of a 
mountain-chain. At the present time depressions and eleva- 
tions, probably caused by accumulating strains, are slowly 
changing the relations of land and sea upon many parts of the 
earth’s surface. In the same way the downward and upward 
movements which would be caused by the burden of the ice- 
sheet and its removal are doubtless in many places complicated 


500 THE ICE AGE IN NORTH AMERICA, 


by concomitant or subsequent movements thus due to defor- 
mations under strains, by which the elevation attributable to 
the departure of the ice-sheet may be augmented or partly or 
wholly counteracted, giving much irregularity to the glacial 
and post-glacial oscillations of the land. 

Jamieson appears to have been the first, in 1865, to suggest 
this view, which I receive from him, that the submergence of 
glaciated lands when they were loaded with ice has been caused 
directly by this load pressing down the earth’s crust upon its 


fused interior, and that the subsequent re-elevation was a 


hydrostatic uplifting of the crust by underflow of the inner 
mass when the ice was melted away.* Two years later Whit- 
tlesey published a similar opinion.+{ In 1868 Shaler referred 
the subsidence of ice-covered areas to a supposed rise of iso- 
geothermal lines in the subjacent crust, operating, in conjunc- 
tion with the ice-sheet, to produce downward flexure ;{ but in 
1874 and later he regards the depression as due directly to the 
weight of the ice, and the re-elevation as due to its removal. * 
The same view is advanced also by Chamberlin to account for 
the basins of the Laurentian lakes, where he believes a con- 
siderable part of the glacial depression to have been permanent. | 


* “Quarterly Journal of the Geological Society,” vol. xxi, p. 178. Later 
discussions of this subject by Mr. Jamieson are in the ‘‘ Geological Magazine,” 
II, vol. ix, pp. 400-407 and 457-466, September and October, 1882; and III, 
vol. iv, pp. 344-348, August, 1887. In the article last cited, he applies this ex- 
planation to the changes of the beaches of Lake Agassiz, which up to that time 
I had attributed mainly to ice attraction. The same principle, however, was 
brought forward by Herschel in 1836, and had been advocated by Professor 
James Hall, of New York, in 1859, in attributing to the weight of sediments the 
long continued subsidence of the areas on which they have been deposited in 
great thickness. 

--+ “Proceedings of the American Association for the Advancement of 
Science,” vol. xvi, pp. 92-97. 

_ “ Proceedings of the Boston Society of Natural History,” vol. xii, pp. 
128--136. 

* “ Proceedings of the Boston Society of Natural History,” vol. xvii, pp. 
288-292; “Memoirs,” ibid., vol. ii, pp. 335-340; ‘American Journal of 
Science,” III, vol. xxxiii, pp. 220, 221, March, 1887; “ Scribner’s Magazine,” 
vol. i, p. 259, March, 1887. 

-. || “ Geology of Wisconsin,” vol. i, 1888, p. 290; “ Proceedings of the Ameri- 


can Association for the Advancement of Science,” vol. xxxii, 1883, p. 212. The 
Ba Met eee ti Shc aua ea at ‘ 


a 


THE CAUSE OF THE GLACIAL PERIOD. O01 


Accompanying the subsidence of ice-loaded areas, there were 
doubtless uplifts of contiguous regions, perhaps sometimes 1n- 
cluding outer portions of the country glaciated. For example, 
the Quatenary elevation of which Le Conte finds evidence in 
the Sierra Nevada and northward may have been contempora- 
neous and correlative with depression of the northern parts of 
the continent beneath its ice-sheet. Furthermore, instead of 
being wholly offset by deformation of the crust, the glacial 
depression may have produced also extensive extravasation of 
lava, as is suggested by Jamieson * and Alexander Winchell, + 
for the vast Quaternary lava-flows of California, Oregon, Wash- 
ington, and a large adjacent region. As Jamieson well re- 
marks, this result would tend to cause a permanence of part of 
the depression of the ice-covered area. However it may have 
been caused, probably such permanent Quaternary subsidence 
is true for the coasts of many glaciated countries, as shown by 
* fiords, and for the basins of the Laurentian lakes, which, ex- 
cepting Erie, are depressed several hundred feet below the level 
of the ocean. 

One of the most interesting fiords of North America is that 
of the Saguenay, tributary to the St. Lawrence. Along a 
distance of about fifty miles the Saguenay is from 300 to 840 
_ feet deep below the sea-level ; its adjoining cliffs rise abruptly 
in some places 1,500 feet above the water ; and the width of its 
wonderfully sublime and picturesque gorge varies from about 
a mile to one mile and a half.{ This fiord, like the many 
‘which indent our Eastern coast from Maine to Labrador and 
Greenland, and our Western coast from Puget Sound to the 
Arctic Ocean, was eroded by a stream that flowed along the 
bottom of the gorge when it was above the sea ; and this erosion 
was probably going forward in the epoch immediately preced- 


problems of ice attraction and of deformation of the earth’s crust have been 
further discussed by President Chamberlin before the Philosophical Society of 
Washington, March 13, 1886; and, jointly with Professor Salisbury, in the 
“Sixth Annual Report, United States Geological Survey,” pp. 291-304. 

* “ Geological Magazine,” IT, vol. ix, 1882, p. 405. 

+ “ American Geologist,” vol. i, pp. 139-143, March, 1888. 

¢ “J. W. Dawson, “ Notes on the Post-Pliocene Geology of Canada,” 1872, 
p. 41. 


502 THE ICH AGE IN NORTH AMERICA. 


ing the Ice age, for earlier subsidence during any period of 
much length, geologically speaking, would have caused the 
submerged valley to be filled with sediments. The preglacial 
elevation of the Saguenay region therefore appears to have been 
at least 1,000 feet greater than now; and it seems to be similarly 
proved by fiords that nearly the entire extent of the conti- 
nental glaciated area was considerably higher before than after 
glaciation. 

There is also evidence that part of the Atlantic coast of the 
United States close south of the limits of glaciation was at least 
for a. short time preceding the Glacial period uplifted much 
above its present height. The submarine Hudson River fiord * 
indicates that the vicinity of New York and Philadelphia then 
stood 2,800 feet above the sea, and that it afterward slowly 
sank 1,600 feet, while a bar of that height was formed by coast- 
wise wash across the mouth of the fiord. In this remarkable 
preglacial elevation, and in its being more or less shared by the 
whole northern half of the continent, the formation of the 
North American ice-sheet seems to be explained. If this was 
the cause of glaciation, probably the formerly greater height of 
about 1,000 feet on the Saguenay was not exceptional. In- 
deed, the elevation there and over large portions of the vast 
territory of Canada, bounded on the east, north, and west by 
fiord-indented: coasts, may have been much more than is 
measured by the depth of the Saguenay River. 

Going a step further back, we may regard this northward 
elevation as a distortion of the earth’s form in the storage of 
energy of lateral pressure which culminated, with the introduc- 
tion of the new factor of northward depression by the ice 
weight, in the Quaternary uplifts of the Western plains, the 
Rocky Mountains, the Sierra Nevada, and the Great Basin. 
These important changes in the elevations of great areas during 
the comparatively short Quaternary period seem to be consistent 
only with the hypothesis that our globe has a comparatively 
thin crust and a molten interior. 

In the Glacial period significant changes of the sea-level 


* A. Lindenkohl, “‘ American Journal of Science,” III, vol. xxix, pp. 475-480, 
with plate, June, 1885. 


THE CAUSE OF THE GLACIAL PERIOD. 503 


were caused : first, by abstraction of water from the ocean and 
its deposition on the land as snow, which under pressure made 
the vast ice-sheets ; and, second, by ice attraction of the ocean, 
_ lowering it still further, except in the vicinity of glaciated 
lands. An area of about 4,000,000 square miles in North 
‘America, and another of about 2,000,000 square miles in 
Europe, were covered by ice-sheets, which in their maximum: 
extent had probably an average thickness of a half or two thirds: 
of a mile, or perhaps even of one mile. Assuming that these 
ice-sheets were contemporaneous, but disregarding ice-fields of 
smaller extent, which probably existed in parts of Asia and of 
the southern hemisphere, as also the glaciers of mountain dis- 
tricts, the lowering of the ocean surface, which covers approxi- 
mately 145,000,000 square miles, would slightly exceed 100 
feet, if the mean depth of the ice accumulation was half a mile. 
More probably the sea over the whole globe was thus depressed 
fully 150 feet, which would correspond to an average of about 
3,600 feet of ice on the glaciated areas of North America and 
Europe. For the second factor in causing such changes, Mr. 
R. S. Woodward’s computations* indicate that gravitation 
toward the ice would further depress the ocean probably 
twenty-five to seventy-five feet within the tropics and in the 
southern hemisphere, while it would raise the level enough 
near the borders of the ice-sheets to counterbalance approxi- 
mately the depression due to the diminution of the ocean’s 
volume, and would lift portions of the North Atlantic and of 
the Arctic Sea perhaps two or three hundred feet higher than 
now. Stream erosion while the sea was lowered to supply the 
ice of the Glacial period may explain the indentations of the 
southeastern coast of the United States, as Pamlico and Albe- 
marle Sounds, besides similar inlets in many other parts of the 
world ; but the excavation of Chesapeake and Delaware Bays 
seems more probably referable, at least in part, to the time of 
preglacial elevation, with the channeling of the now sub- 
merged Hudson fiord. 

When the ice-sheet of the last Glacial doa finally re- 


*“ United States Geological Survey, Sixth Annual Report,” pp. 291-300; 
and “ Bulletin No. 48,” ‘‘ On the Form and Position of the Sea-Level.” 


504 THE ICE AGE IN NORTH AMERICA. 


treated, the land which it had covered stood mostly lower 
than now, as is shown by the occurrence of fossiliferous marine 
deposits overlying the glacial drift up to considerable eleva- 
tions. Near Boston, and northeast to Cape Ann, the coast — 
seems to have been submerged to a slight depth, probably not 
exceeding ten to twenty-five feet. Proceeding toward the 
north and northwest, the elevation of the marine beds lying 
on the glacial drift increases to about two hundred and twenty- 
five feet in Maine, about five hundred and twenty feet in the 
St. Lawrence Valley at Montreal, and four hundred and forty 
feet at a distance of one hundred and thirty miles west-south- 
west of Montreal; but eastward, along the St. Lawrence, it 
decreases to three hundred and seventy-five feet opposite the 
Saguenay, and does not exceed two hundred feet in the basin 
of the Bay of Chaleurs ; while these marine deposits are want- 
ing in Nova Scotia and Cape Breton Island.* This subsidence 
accords well with the explanation that it was due to the press- 
ure of the ice- weight, which was greatest on the highlands 
between the St. Lawrence and Hudson Bay. 

Along the East Main coast of Hudson Bay and on Hudson 
Strait raised beaches are conspicuous, according to Dr. Robert 
Bell, up to heights of at least three hundred feet.t In the 
region draining from the southwest to James Bay, Dr. Bell 
reports marine shells in stratified beds overlying the glacial 
drift along the Moose, Mattagami, and Missinaibi Rivers up 
to about three hundred feet above the sea; { along the Albany 


* A. S. Packard, Jr., ‘Memoirs of the Boston Society of Natural History,” 
vol. i, pp. 231-262. J. W. Dawson, “Notes on the Post-Pliocene Geology of 
Canada” ; and “‘ American Journal of Science,” TI, vol. xxv, 1888, pp. 200-202, 
C. H. Hitchcock, “‘ Proceedings of American Association for the Advancement 
of Science,” Portland, 1873, vol. xxii, pp. 169-175; “Geology of New Hamp- 
shire,” vol. iii, pp. 279-282; and ‘‘ Geological Magazine,” II, vol. vi, 1879, pp. 
248-250. R. Chalmers, “Transactions of the Royal Society of Canada,” sec. iv, 
1886, pp. 1389-145. W. Upham, “ Proceedings of Boston Society of Natural 
History,” vol. xxiv, pp. 127-141, December, 1888; ‘“‘ American Journal of Sci- 
ence,” May, 1889. 

+ ‘Geological and Natural History Survey of Canada, Report of Progress 
for 1877-78,” p. 832 C; for 1882-83-84, p. 31 DD. 

t “Geological and Natural History Survey of Canada, Report of Progress 
for 1875-"76,” p. 340; for 1877-78, p. 7 C, 


THE CAUSE OF THE GLACIAL PERIOD. 905 


and Kenogami Rivers up to a height of about four hundred and 
fifty feet ;* and on the Attawapishkat to about five hundred 
feet above the sea.+ It is also evident that the shores of Hud- 
son Bay are still undergoing elevation,{ unlike the eastern coast 
of the United States and Canada, where the post-glacial uplift- 
ing has ceased, and there is now in progress a very slow sub- 
sidence of the land from New Jersey to the Gulf of St. Law- 
rence. 

Scantier but yet conclusive proofs of the uplift of British 
Columbia after glaciation are found in the valley of the Fraser 
River, and on the Pacific coast, in Vancouver Island and the 
Queen Charlotte Islands. Lamplugh has observed recent ma- 
rine shells in a railway cutting on the west bank of the Harri- 
son River, near its junction with the Fraser, at an elevation 
not less than one hundred feet above the sea.* At New West- 
minster, on the Fraser, near its mouth, raised beaches inclos- 
ing fragments of marine shells are reported by Bauerman about 
thirty feet above the river.|| Fossiliferous marine deposits 
found in the vicinity of Victoria and Nanaimo, in the south- 
east part of Vancouver Island, at small elevations above the 
sea, are believed by Dr. G. M. Dawson to have been formed at 
or near the wasting edge of the ice-sheet ;* and near the mid- 
dle of the northeast side of this island two distinct deposits of 
till occur, with mtervening beds of loess-like silts, from which 


* “ Geological and Natural History Survey of Canada, Report of Progress 
for 1871-72,” p. 112; for 1875-76, p. 340; “Annual Report,” vol. ii, for 
1886, pp. 34 and 38 G. 

+ “Geological and Natural History Survey of Canada, Annual Report,” vol. 
i, p. 27 G. 

t ‘‘Geological and Natural History Survey of Canada, Report of Progress 
for 1877-’78,” pp. 32 C and 25 CC; for 1878-79, p. 21 C; for 1882—’83-’84, 
pp. 26 and 30 DD; “ Annual Report,” vol. i, for 1885, p. 11 DD. 

* “ Quarterly Journal of the Geological Society,” vol. xlii, 1886, pp. 284, 285. 

| “Geological and Natural History Survey of Canada, Report of Progress 
for 1882-—’83-’84,” p. 33 B. 

A “ Geological and Natural History Survey of Canada, Annual Report,” voi. 
ii, for 1886, p. 99 B; “Quarterly Journal of Geological Society,” vol. xxxiv, 
1878, pp. 97, 98, and vol. xxxvii, 1881, p. 279. Compare also Mr. G. W. Lamp- 
lugh’s observations of glacial shell-beds at Esquimault, near Victoria, “ Quar- 
terly Journal of Geological Society,” vol. xlii, 1886, pp. 276-284 


506 THE ICE AGE IN NORTH AMERICA. 


this author infers two periods of glaciation, separated by an 
interglacial epoch, in which the land was submerged from one 
to: two hundred feet.* Again, in the northeast part of the 
Queen Charlotte Islands Dr. Dawson finds evidence of sub- 
mergence to the amount of two or three hundred feet, while 
the glacial conditions still endured. + 

In Europe the glaciated area stood at a greater height be 
fore the Ice age, as is shown by fiords; it was similarly de- 
pressed while loaded with the ice-sheet ; and since then it has 
been partially re-elevated. Its maximum post-glacial uplift 
known in the British Isles, so far as it has not been counter- 
acted by subsequent depression, is five hundred and ten feet, 
near Airdrie, in Lanarkshire, Scotland;{ and in Scandinavia 
it is about six hundred feet.# As in all the North American 
districts noted, these upward movements seem attributable to 
the rise of the earth’s crust, upborne by inflow of a molten 
magma beneath. 

But the derivation of the floras of the Firée Islands, Ice- 
land, and even Greenland from the flora of Europe, demon- 
strates, according to Professor James Geikie, that the portion 
of the earth’s crust extending from Britain and Scandinavia 
to Greenland was uplifted in early post-glacial times about 


* “ Geological and Natural History Survey of Canada, Annual Report,” vol. 
ii, p. 105 B. 

+ “‘ Geological and Natural History Survey of Canada, Report of Progress 
for 1878-79,” p. 95 B. Further important notes of recent changes in level of 
.the coast of British Columbia, and of Washington Territory and Alaska, are 
given by Dr. Dawson in the “Canadian Naturalist,” new series, vol. viii, pp. 241 
—248, April, 1877. He concludes that this area had a preglacial elevation at 
least about nine hundred feet above the present sea-level, during part or the 
whole of the Pliocene period, this being indicated by the fiords; that it was 
much depressed in the Glacial period; and that in post-glacial time it has been 
re-elevated to a height probably two or three hundred feet greater than now, 
followed by subsidence to the present level, the latest part of this oscillation 
being a somewhat rapid depression of perhaps ten or fifteen feet during the 
latter part of last century—a movement which may still be slowly going on. 

t ‘Quarterly Journal of the Geological Society,” vol. vi, 1850, pp. 386-388, 
and vol. xxi, 1865, pp. 219-221; “ American Geologist,” vol. ii, pp. 371-379, 
December, 1888. 

# “Geological Magazine,” I, vol. ix, 1872, p. 309; and II, vol. ii, 1875, 
p. 390. 


, 
: 
: 
| 


THE CAUSE OF THE GLACIAL PERIOD. 507 


three thousand feet higher than now ;* and the same author 
shows that nm interglacial time tropical animals passed from 
Barbary into Spain upon land where now the Strait of Gi- 
braltar has a depth of one thousand feet.t These changes in 
the relations of land and sea can not be ascribed to glacia- 
tion, but seem to be distortions of the earth’s form, such as 
may be attributed to the action of strain upon the crust by 
which the earth can become reduced in volume through the 
subsidence and elevation of extensive areas during intervals 
between epochs of mountain-building. In the same class of 
changes are also to be included, wholly or in part, the post- 
glacial elevation of Grinnell Land and the northwestern coast 
of Greenland, one thousand to sixteen hundred feet ; { post- 
Pliocene upward movements of two thousand feet or more in 
Jamaica and Cuba ;* the recent uplift of the coast of Peru at 
least twenty-nine hundred feet,|| which in diminished amount 
seems to extend along the whole range of the Andes ; its prob- 
able connection with the upheaval of the Cordilleras of North 
America, where Le Conte believes that the elevatory move- 
ments reached their greatest intensity in early Quaternary 
time, causing a rise of several thousands of feet in the Sierra 
Nevada ;“ and the apparently correlative subsidence of a great 


* “ Prehistoric Europe,” pp. 513-522, and 568, with Plate E. 

+ “ Prehistoric Europe,” pp. 325, 337-339 ; ‘‘ Quarterly Journal of the Geo- 
logical Society,” vol. xxxiv, 1878, p. 505. 

¢ “ Quarterly Journal of Geological Society,” vol. xxxiv, 1878, p. 66; “ Geo- 
logical Magazine,” ITI, vol. i, 1884, p. 522. 

* J. G. Sawkins, “Reports on the Geology of Jamaica,” 1869, pp. 22, 23, 
307, 311, 324-329; W. O. Crosby, “On the Mountains of Eastern Cuba,” “ Ap- 
palachia,” vol. iii, pp. 129-142. Compare William M. Gabb’s memoir, ‘‘ On the 
Topography and Geology of Santo Domingo,” “Transactions of the American 
Philosophical Society,” vol. xv, pp. 103-111. | 

|| A. Agassiz, “ Proceedings of the American Academy of,Arts and Sciences,” 
vol. xi, 1876, p. 287; and “Bulletin of the Museum of Comparative Zodlogy, at 
Harvard College,” vol. iii, pp. 287-290. Above this height, at which corals are 
found attached to rocks, recent elevation of much greater amount seems to be 
indicated by terraces, by saline deposits, and by the presence of eight species of 
Allorchestes—a genus of marine crustacea, in Lake Titicaca, 12,500 feet above 
the sea. 

4“ American Journal of Science,” III, vol. xxxii, pp. 167-181, September, 
1886. 


508 THE ICH AGE IN NORTH AMERICA. 


area dotted with coral islands in the Pacific. The Quaternary 
uplifts of the Andes and Rocky Mountains and of the West 
Indies make it nearly certain that the Isthmus of Panama has 
been similarly elevated during the recent epoch. On the line 
of the Panama Railway the highest land rises only two hundred 
and ninety-nine feet above the sea, and the highest on the 
Nicaragua Canal is about one hundred and thirty-three feet, 
while the isthmus nowhere attains the height of one thousand 
feet.* It may be true, therefore, that the submergence of this 
isthmus was one of the causes of the Glacial period, the con- 
tinuation of the equatorial oceanic current westward into the 
Pacific having greatly diminished or wholly diverted the Gulf 
Stream, which carries warmth from the tropics to the northern 
Atlantic and northwestern Europe. 

In view of the extensive recent oscillations of land and 
sea both in glaciated and unglaciated regions, it seems a rea- 
sonable conclusion that, while some of these movements have 
resulted directly from the accumulation and dissolution of ice- 
sheets, more generally, when the whole area of the earth 1s 
considered, they have been independent of glaciation. May 
not such movements of the earth’s crust, then, have elevated 
large portions of continents, as the northern half of North 
America and the northwestern part of Europe, to heights like 
those of the present snow-line on mountain-ranges, until these 
plateaus became deeply channeled by fiords and afterward coy- 
ered by ice-sheets ? For the recentness of the latest glaciation, 
believed to have ended in the northern United States not more 
than ten thousand to six thousand years ago,t forbids our re- 


a — = 


* Charles Ricketts, ‘‘The Cause of the Glacial Period, with reference to the 
British Isles,” “Geological Magazine,” II, vol. ii, 1875, pp. 573-580. A. R. 
Wallace, “The Geographical Distribution of Animals,” vol. i, p. 40. 

+ N. H. Winghell, “Geology of Minnesota,” “Fifth Annual Report,” for 
1876, and “Final Report,” vol. ii, pp. 818-341; “Quarterly Journal of the 
Geological Society,” vol. xxxiv, 1878, pp. 886-901. E. Andrews, “ Transactions 
of the Chicago Academy of Sciences,” vol. ii. James C. Southall, ““The Epoch 
of the Mammoth and the Apparition of Man upon the Earth,” 1878, chaps. xxii 
and xxiii. G. F. Wright, ‘“‘ American Journal of Science,” III, vol. xxi, pp. 120- 
123, February, 1881; “The Ice Age in North America,” chap. xx. G. K. Gil- 
bert, “Proceedings of the American Association for the Advancement of Sci- 
ence,” vol. xxxv, 1886. 


q 
¥ 
f 
‘ 
' 


THE CAUSE OF THE GLACIAL PERIOD. 509 


ferring the glacial climate to conditions brought about by a 
period of increased eccentricity of the earth’s orbit from two 
hundred and forty thousand to eighty thousand years ago, 
which has been so ably maintained by Croll and Geikie; and 
some other adequate cause or causes must be sought for the 
successive Quaternary glacial epochs of these great continental 
areas and other districts of smaller extent both in the northern 
and southern hemispheres ; also for the rare occurrence of gla- 
cial conditions in various portions of the earth during past 
geologic ages, especially in the Carboniferous and Permian 
periods. The principal cause of all these epochs of glaciation 
seems to the writer to be probably found by the clew supplied 
in the relations already stated of the earth’s crust and interior, 
whereby they become somewhat distorted from the spheroidal 
form while the process of contraction goes forward, the lateral 
pressure bearing down some portions of the earth’s surface, 
and uplifting other extensive areas. Protuberant plateaus, 
swept over by moisture-laden winds, would be the gathering- 
grounds of vast ice-sheets, which would probably wax and 
wane with the changes of the earth’s attitude toward the sun, 
by which the earth’s place in any season, as summer, alternates 
from aphelion to perihelion, and back to aphelion in cycles of 
twenty-one thousand years. A similar explanation of the Gla- 
cial period was long ago proposed by Lyell and Dana, but 
without referring the elevatory movements to the earth’s de- 
formation by contraction and accumulating lateral pressure 
while approaching an epoch of mountain-building, which 
fundamental principle was first suggested to me in an article 
from the pen of Professor W. O. Crosby, on the origin and 
relations of continents and ocean basins.* 

During the periods immediately preceding great plications 
and shortening of segments of the earth’s crust involved in the 
formation of lofty mountain-ranges, the broad crustal move- 
ments causing glaciation would be most wide-spread and attain 
their maximum vertical extent. The accumulation of ice- 
sheets may have brought about the depression of their areas, 


* “Proceedings of the Boston Society of Natural History,” 1883, vol. xxii, 
pp. 455-460. 


510 THE ICE AGE IN NORTH AMERICA. 


with corresponding elevation of other plateaus, which in turn 
would become ice-covered, so that the epochs of glaciation of © 
the northern and southern hemispheres may have alternated 
with each other ;* and this may have been several times re- 
peated, because of crustal oscillations due to ice-weight and its 
removal, the effects of elevation and depression of the land — 
being re-enforced by climatic influences arising from the revolu- 
tion each twenty-one thousand years in the place of the seasons. 
When the building up of a great range of mountains ensued, 
which may have been initiated and accelerated by the repeated | 
depressions under ice-weight and consequent transfers of the 
earth’s deformation from one region to another, the accumu- 
lated strain in the earth’s crust, with development of immense 
lateral pressure, would be diminished below the limit of its 
competency to cause glaciation. 

Such Quaternary mountain-building is known to have oc- 
curred on a most massive scale in Asia, where the Himalayas, 
stretching fifteen hundred miles from east to west, and tower- 
ing twenty thousand to twenty-nine thousand feet above the 
sea, are known to have been formed, at least in great part, and 
perhaps almost wholly, during this latest geologic period,f 
contemporaneously with the glaciation of North America, 
Kurope, and portions of the southern hemisphere. Within the 
same time the great table-land of Thibet,{ and much of central 
and. northwestern Asia, have been uplifted ; the tract extend- 
ing from the Black and Caspian Seas northeast to the Arctic 
Ocean has risen to form a land-surface ; and the deep basin of 
Lake Baikal has been probably formed in connection with 
these crustal movements. Accompanying the formation of the 
Himalayas, there has been doubtless much disturbance by 
faults, local uplifts, and here and there plication of strata 


* Compare the opinions of Hutton, cited in A. Geikie’s “ Text-Book of Geolo- 
gy,” second edition, p. 912, that the former greater extension of glaciers in New 
Zealand was caused by an increase in the elevation of the land, and that it be- 
longed to a much earlier time than the Ice age in the northern hemisphere, 
probably to the Pliocene period. 

+ “Manual of the Geology of India,” by H. B. Medlicott and W. T. Blanford, 
Calcutta, 1879, Part I, pp. lvi, 372; Part II, pp. 569-571, 667-669, 672-681. 

t Ibid., Part II, pp. 585, 586, 669-672. 


THE CAUSE OF THE GLACIAL PERIOD. oll 


along the whole complex east to northwest and west mountain 
system of Oceania, Asia, Europe, and Northern Africa, from 
‘New Guinea, the Sunda Islands, Anam, and Siam, to the Can- 
casus, Carpathians, Balkans, Apennines, Alps, Pyrenees, and 
Atlas Mountains, stretching quite across the eastern hemi- 
sphere ; but the greater part of the relief from the previously 
existing deformation of the earth was doubtless along the cen- 


tral part of the belt, in the colossal Himalayan range. In 
like manner the North American Cordilleras and the Andes, 
reaching in one continuous mountain system from the Arctic 


Circle to Cape Horn, have experienced within the same period 
great disturbances, as already noted, similar to those of the 


mountains of Southern Europe and the adjacent part of Africa. 
‘With this American orographic belt is also probably to be 


associated the mountain system, consisting largely of volcanoes 


‘now active, which forms the Aleutian Islands, Kamtchatka, 
-the Kurile Islands, Japan, Formosa, the Philippines, Borneo, 
and Celebes, lying nearly in the same great circle with the 


Andes and Rocky Mountains, and with them continuous in 
an arc of about two hundred and forty degrees. Along two 


lines transverse to each other, one having an extent of half 


and the other of two thirds of the earth’s circumference, the 
great lateral pressures of the earth’s crust, which probably 
caused the elevation and glaciation of extensive areas during 
the Quaternary period, have been relieved by plication, faults, 
and uplifts, in the processes of the formation of mountain- 
ranges. * 

Combined with oscillations of the earth’s crust, which are 
here regarded as the primary cause of the growth and decline 
of ice-sheets, many other concomitant conditions, notably 
changes in aérial and oceanic currents, and the earth’s cycles of 
twenty-one thousand years through precession and nutation, 
enter into the complex causation of recurrent glacial and inter- 
glacial epochs, and serve to intensify or to mitigate the severity 
of the glaciation due to elevation. The influences of these 
conditions would be nearly the same that are claimed for them 


* See Prestwich’s “Geology,” vol. i, chap. xvii, treating of the relative ages 
of the principal mountain-ranges of the world. 


512 THE ICH AGE IN NORTH AMERICA. 


in the luminous glacial theory of Croll, but their origin and - 
effectiveness toward causing a glacial climate are here referred 
to extensive crust oscillations instead of eccentricity of the 
earth’s orbit. The prolonged warm interglacial epoch, or sev- 
eral such epochs, of which evidence is obtained in the Qua- 
ternary deposits of Kurope and North America, preceded and 
followed by severe arctic climate and ice-sheets, meet an ade- 
quate and consistent explanation in the view here taken ; and, 
indeed, the same reasoning that is presented by Croll in the 
details of the secondary elements of his theory seems equally 
applicable if these depend primarily on crustal elevation. 

The principal interglacial epoch in the United States, un- 
der this view, may well have been several times longer than 
either the previous or subsequent epochs of glaciation, or than 
the whole of post-glacial time, as claimed by McGee ;* but it 
does not follow that an exact parallelism will be found in the — 
glacial history of Europe. Former extension of vast glaciers 
in the Rocky Mountains and Andes, the Pyrenees and Alps, 
the Atlas range, the Caucasus, the Himalayas, and elsewhere, 
far exceeding the glaciers of the present time, may be due to 
the uplift of these mountains much above their present height, 
followed by subsidence t+ with retreat of the ice ; but these os- 
cillations and resulting alternations of climate were not proba- 
bly synchronous everywhere. ‘The highest mountain-ranges in 
four grand divisions of the world—namely, Asia, Europe, and 
North and South America—were doubtless largely uplifted and 
plicated, with formation of deep adjoining lakes, during the 
early part of the Quaternary period. Twice upheavals of the 
whole district of the Alps seem to have covered the region with 
great accumulations of ice, which each time may have depressed 
the area, first to be succeeded by the formation of interglacial 
deposits with lignite, and during each depression to send down 
floods, spreading loess along the Rhine, the Rhone, and the 
Danube.t After the later epoch of subsidence and glacial re- 


* “ American Journal of Science,” III, vol. xxxv, pp. 463-466, June, 1888. 

+ A. Geikie’s “ Text-Book of Geology,” second edition, p. 934. 

+ J. Geikie’s “Great Ice Age,” second edition, chapters xxxiii and xxxty, 
and his “ Prehistoric Europe,”’ chapters ix and xi. 


~~ «as 227 ee OO ee ee 


i Ad ee ee lle 


THE CAUSE OF THE GLACIAL PERIOD. 513 


cession, there seems to have been a renewal of elevation, as 
shown by the height and slopes of the loess. 

Asia had no extensive ice-sheet like those of Europe and 
North America, probably because a sufficient elevation was not 
attained there until the Himalayas and Thibet were uplifted in 
the Glacial period. Their southern latitude and the position 
of Thibet and Mongolia in an arid and partly rainless belt, 
which stretches thence west to the Sahara, forbade their glacia- 
tion ; but from these recently uplifted Asiatic table-lands and 
mountains the most extensive Quaternary deposits of the world 
have been brought down by rivers and spread in the vast low 
plains of Siberia, eastern China, and northern India, sloping 
gently toward the sea, into which the finer part of this allu- 
vium is carried. All the puzzling features of the Chinese loess 
formation,* reaching to great elevations with such thickness 
and slopes of its surface that it could not be so accumulated as 
alluvium of flooded streams under the present conditions, seem 
to be readily explained by referring its deposition to annual 
floods from immense snow-melting, during the European Gla- 
cial epochs, upon the gradually rising central part of the Asi- 
atic Continent, which consists largely of easily erosible strata, 
and had in preglacial time become extensively disintegrated by 
weathering under a dry climate. 

With this reference of glaciation primarily to oscillations 
of land, a new element of Quaternary history is introduced, 
which seems to help much in accounting for peculiarities in 
the areal distribution of identical or closely allied species of 
animals and plants that have doubtless sprung from a common 
source but have now become widely separated. Not only are 
we able to follow Gray in his tracing the origin of the big trees 
of California, of the species in the flora of the eastern United 
States—which are the same with species of Japan, China, and 
the Himalayan region, or are represented there by closely re- 
lated forms, though unrepresented in Hurope—and of mount- 


* Baron Richthofen, “ Geological Magazine,” II, vol. ix, 1882, pp. 293-305. 
J. D. Whitney, “ American Naturalist,” vol. xi, pp. 705-713, December, 1877. 
R. Pumpelly, ‘“‘ American Journal of Science,” III, vol. xvii, pp. 1383-144, Feb- 
ruary, 1879. -E. W. Hilgard, “American Journal of Science,” III, vol. xviii, 
pp. 106-112, August, 1879. 


514 THE ICE AGE IN NORTH AMERICA. 


ain plants identical with those of the Arctic zone ;* but also we 
may now more satisfactorily bridge over the tropics and equa- 
tor, by uplifts and subsidences of mountain-ranges, so that 
species incapable of enduring a torrid climate could sometimes 
become dispersed even to such distances as from north tem- 
perate latitudes to Tierra del Fuego and the Cape of Good 
Hope. + 

It seems probable that the rate of the earth’s contrac 
has been somewhat uniform throughout the vast ages known 
to us by the researches of geology ; but the corrugation of the 
earth’s surface in mountain-building has been much more rapid 
in some epochs than in others, and between the times of for- 
mation of great mountain-ranges there have been long intervals. 
of quietude. { The slowly progressing contraction of the globe 
has been uninterrupted, and in some way the cooled outer part 
of the crust which has not shared in this diminution of volume 
has been able to accommodate itself to the shrinking inner 
mass. As stated on a previous page, this has probably resulted 
in distortion of the earth’s form, both of the whole thickness 
of the crust and of the probably molten interior, within mod- 
erate limits during the periods of quiet, until so much lateral 
pressure has been accumulated as to compress, fold, and uplift 
the strata of a mountain-range. In attributing the severe 
climate of glacial epochs to great uplifts of the areas glaciated 
through such deformation preparatory to the process of mount 
ain-building, it is distinctly implied that the Quaternary period 
has been at first exceptionally marked by such broad crustal 
movements, and has since gained comparative rest from the 
lateral stress to which they were due by equally exceptional 


Pee a 


* “Sequoia and its History,” “ Proceedings of the American Association for 
the Advancement of Science,” Dubuque, vol. xxi, 1872, and “ American Jour: 
nal of Science,” III, vol iv; “ Forest Geography and Archeology,” “ American 
Journal of Science,” III, vol. xvi, 1878 ; ‘ Characteristics of the North Ameri; 
can Flora,” ‘‘ Report of the British Association for the Advancement of Science,” 
Montreal, 1884, and ‘‘ American Journal of Science,” III, vol. xxviii. 

+ Darwin’s “ Origin of Species,” chapter xi. Wallace’s “ Geographical Dis- 
tribution of Animals,” chapter iii, and his ‘“‘ Island Life,” chapter vii. 

t Dana’s “ Manual of Geology,” third edition, p. 795 ; Prestwich’s “ Geology " 
vol. i, chap. xvii. : 


THE CAUSE OF THE GLACIAL PERIOD. 515 


plication, uplifts, and faults in the birth and growth of mount- 
ains. Further, it is implied also that stress in the earth’s crust 
had been gradually increasing through long previous time, 
while the processes of mountain-building failed to keep pace 
with contraction, but were still sufficient to keep the earth’s 
deformation less than is required to produce glaciation ; for no 
evidences of intense and widely extended glacial conditions are 
found in the great series of Tertiary and Mesozoic formations, 
representing the earth’s history through probably ten or fifteen 
millions of years. And indeed these conclusions, drawn from 
the Quaternary Glacial period and the absence of glaciation 
through vast eras preceding, accord well with the known age 
and stages of growth of mountain-ranges that have been formed 
during these eras. No epoch since the close of Palzeozoic time 
has been more characterized by mountain-building than the 
comparatively short Quaternary, whose duration may probably 
be included within one hundred thousand or two hundred 
thousand years. The continuation of the earth’s faunas and 
floras, with only very slight changes of species and exceedingly 
rare instances of extinction through the Quaternary period, not- 
withstanding its remarkable vicissitudes of climate and changes 
in the relative heights of land and sea, which seem especially 
adapted to produce both modifications and extinctions of or- 
ganic forms, bears indisputable testimony of the brevity of this 
period, when compared with those of Tertiary and Mesozoic 
time. As we extend our investigations backward in the geo- 
logic record, the species now existing are found in decreasing 
numbers until we come to the beginning of the oldest. In 
their places very different species, genera, orders, and groups 
_tenanted the earth before them ; and the gradual and doubtless 
very slow evolution of the present from the past must have re- 
quired duration almost incommensurable by years and centu- 
ries. But the total of mountain-building that has taken place 
during the Mesozoic and Tertiary eras is disproportionately 
small in comparison with that of the Quaternary period, even 
when ample allowance is made for long and very great denu- 
dation. 

Not until we go back to the Permian and Carboniferous 
periods are numerous and widely distributed proofs of very 


516 THE ICE AGE IN NORTH AMERICA. 


ancient glaciation encountered. The atmosphere had been 
purified by the formation of Paleozoic limestones of great 
thickness, and by the storing up of the principal coal-deposits 
of the world ; and these changes in the air had quite surely 
produced eee diversities of climate than before existed, 
especially in respect to the range of temperature in the seasons 
and in the several zones. Alternating beds of coal, shales, and 
sandstones, which form the coal-measures, indicate oscillations 
of level and climatic conditions much like those of the Qua- 
ternary period ;* and bowlder-bearing deposits, sometimes 
closely resembling till and including striated stones, while the 
underlying rock also occasionally bears glacial grooves and 
striz, are found in the Carboniferous or more frequently the 
Permian series in Britain, France, and Germany,t Natal,t 
India,* and southeastern Australia.|| In Natal the striated 
glacier floor is in latitude 30° south, and in India only 20° 
north of the equator. During all the earth’s history previous 
to the Ice age, which constitutes its latest completed chapter, 
no other such distinct evidences of general or interrupted and 
alternating glaciation have been found ; and just then, in close 
relationship with extensive and repeated oscillations of the 
land, and with widely distant glacial deposits and striation, 
we find a most remarkable epoch of mountain-building, sur- 
passing any other time between the close of the Archean era 
and the Quaternary. The Appalachian Mountain system of 
the United States, with its grand plications and upheaval of 
the whole Paleozoic group of rocks, belongs to this epoch, 
and the same line of disturbance extends. by faulting and up- 
hifts northeastward to Gaspé and Newfoundland. In Europe 


* Croll’s “‘ Climate and Time,” chap. xxvi. 

+ “Climate and Time,” chap. xviii; Wallace’s ‘Island Life,” chap. ix. 

t “Quarterly Journal of the Geological Society,” vol. xxvi, 1870, pp. 514—- 
517; vol. xxvii, 1871, pp. 57-60. 

# “ Manual of the Geology of India,” Part I, pp. xxxv—xxxviii, 102, 109-112, 
229. 

| “Quarterly Journal of the Geological Society,” vol. xliii, 1887, pp. 190- 
196. “Die carbone Eiszeit,” by Dr. W. Waagen, “ Jahrbuch d.k.k. geol. Reich- 
enstalt,” Vienna, 1888, vol. xxxvii, Part II, pp. 145-192; reviewed in the 
“ American Geologist,” vol. ii, pp. 886-340, November, 1888. 


Ns 


leer: ak ~”, 


THE CAUSE OF THE GLACIAL PERIOD. O17 


the Permian period ended with disturbance and mountain- 
building along a somewhat irregular west-to-east course through 
southern Ireland, Wales, England, northern France, Belgium, 
Germany, and southern Russia ;* and it is to be remarked 
that this European orographic line lies approximately in the 
same great circle with the Appalachian ranges, both being in- 
cluded by an arc of ninety degrees. Transverse to this circle 
the Sinian Mountain system of eastern Asia was formed in the 
same epoch, stretching from southwest to northeast along the 
border of the Old World as the Appalachians similarly bound 
our own contiuent.t{ Each of these mountain systems was 
perhaps much longer than the extent now remaining, and each 
has been reduced by erosion to only moderate heights ; but it 
is not improbable that their altitude originally was like that 
of the loftiest ranges of the world, some of which have been 
formed and the others much uplifted during the last geologic 
period. 

The shortness of the time that has elapsed since the latest 
glaciation of North America, according to the observations 
and computations of N. H. Winchell, Andrews, Wright, and 
Gilbert, shows that this cold epoch was not coincident with 
the period of eccentricity of the earth’s orbit, which is regarded 
by Croll, Geikie, and Wallace as the primary cause of the Ice 
age. Eccentricity, therefore, had no share in producing this 
most recent glaciation, which was more intense and severe, 
and probably more sudden and brief, than the earlier very cold 
epoch of the Ice age, as indicated by comparison of the mo- 
rainic and other drift deposits. Furthermore, it seems proba- 
ble that the Quaternary Glacial period, including its two or 
more epochs of glaciation, each subdivided by episodes of tem- 
porary retreat and readvance of the ice, besides the principal 
interglacial epoch of warm or temperate climate, and perhaps 
complete departure of the North American ice-sheet, was 
wholly subsequent to the maximum eccentricity which the 


* Prestwich’s “ Geology,” vol. i, p. 300. 

+ ‘‘ Geological Researches in China, Mongolia, and Japan,” by Raphael Pum- 
pelly, “‘ Smithsonian Contributions,” vol. xv, 1867, chap. vii. The conclusions 
reached by Pumpelly concerning this mountain system are fully confirmed by 
the subsequent grand work of Baron Richthofen on the geology of China. 


518 THE ICH AGE IN NORTH AMERICA. 


earth’s orbit attained two hundred thousand years ago. 
Through all the past ages of geology, also, the earth has from 
time to time passed through similar stages of increased eccen- 
tricity, sometimes having a still higher maximum,* which we 
should expect, in accordance with Croll’s theory, to find re- 
corded by deposits of glacial drift intercalated in the Tertiary, 
Mesozoic, and Paleozoic strata of circumpolar and temperate 
regions. But the recentness of the Quaternary glaciation, and 
the general absence of earlier drift formations,+ excepting 
within the Carboniferous and Permian periods, seem to demon- 
strate that eccentricity has not been the primary cause of gla- 
ciation, either with the concurrence of climatic conditions and 
changes of the course of winds and of oceanic currents such 
as might attend its slight modifications of the seasons, while 
the present arrangement and relative heights of land and sea 
were unchanged, or, as Wallace suggests,{ with much greater 
elevation of the areas glaciated, which he thinks to have been 
necessary, seconding the effects of eccentricity, for the accumu- 
lation of ice-sheets. Indeed, we may well doubt that eccen- 
tricity has exerted any determining influence in producing 
unusual severity of cold either during the Quaternary or any 
former period. 

Elevation of broad areas, as half of North America and half 
of Europe, either synchronously or in alternation, to such 
heights that their precipitation of moisture throughout the 
year was nearly all snow, forming gradually ice-sheets of great 
thickness, seems consistent with the conditions of the earth’s 
crust and interior, which are indicated by the changes in the 
levels of glaciated countries. A molten magma beneath the 
solid crust appears, in connection with contraction of the earth 


* Croll’s ‘Climate and Time,” chap. xix, with plate iv, representing the 
variations in the eccentricity of the earth’s orbit for three millions of years before 
A. D. 1800, and one million of years after it. 

+ Nordenski6ld reports that, in sections observed by him in Spitzbergen and 
Greenland, including all formations from the Silurian to the Tertiary, and occu- 
pying in the aggregate, as he estimates, not less extent than a thousand English 
miles, he has never observed erratic blocks nor any evidence of glacial action.— 
“Geological Magazine,” IT, vol. ii, 1875, pp. 525-532, and vol. iii, 1876, p. 266. 

+ “Island Life,” chaps. viii, ix, and xxiv. 


THE CAUSE OF THE GLACIAL PERIOD. 519 


and the formation of mountain-ranges, to afford an adequate 
explanation of glaciation. It is probable that the great up- 
lifts which are thus supposed to have caused ice-accumulation 
were very slow in their progress, and that their effect upon 
extensive continental areas was so distributed that the maxi- 
mum changes in slope on thei borders would nowhere exceed 
twenty or thirty feet per mile, while perhaps some portions 
of the uplifted region would receive no change of slope. And 
the subsidence beneath the weight of accumulated ice was 
probably equally slow and similarly distributed, no limited 
district being greatly changed. Excepting the rare instances 
where disturbances of mountain-building or extraordinary ris- 
ing or sinking of mountain-ranges were associated with these 
movements, the contour of the country, with its valleys, hills, 
and mountains, has remained in general the same from pre- 
glacial time through the Ice age to the present with only 
changes of slope, small in any limited tract, which in long 
distances allowed great upheavals and depressions. The ele- 
vation of the central part of glaciated areas, with downward 
slopes on all sides, would favor the outward flow of the ice-sheets 
and their erosion and transportation of the drift. But mount- 
ains and hills jutted upward in ridges and peaks within the 
moving ice-sheet, as they now stand forth in bold relief above 
the lowlands; and the ice with its inclosed drift was pushed 
around and over them, some portions being deflected on either 
side, and usually a larger part being carried upward across 
their tops. Katahdin, the White Mountains, the Green Mount- 
ains, and the Adirondacks, stood directly in the pathway of 
the ice outflowing southeastward from the Laurentian high- 
lands. Its thickness in northern New England and northern 
New York seems to be measured approximately by the eleva- 
tion of the highest of these summits above the adjoining low- 
lands, about one mile; but northward the ice-sheet evidently 
was somewhat deeper upon the valley of the St. Lawrence, and 
Professor Dana’s estimate seems still reliable, that its maxi- 
mum depth, lying on the water-shed between this valley and 
Hudson Bay, was probably about two miles. 


520 THE ICE AGE IN NORTH AMERICA. 


SUPPLEMENTARY NOTES. 
By WARREN UPHAM. 


The twenty-one years which have elapsed since the prep- 
aration of this chapter have not furnished any facts mate- 
rially to modify the views here presented. ‘The most impor- 
tant additional discussions of the subject are those of Messrs. 
Chamberlin and Salisbury advocating an atmospheric the- 
ory,* which they state as follows, when treating of the Permian 
Glacial epoch. 

“The increased area of the land, and its increased ele- 
vation, give increased contact between the atmosphere and 
the rocks of the earth susceptible of carbonation and oxida- 
tion, as already indicated. As a result, the atmosphere 
lost carbon dioxide and oxygen at a more rapid rate than in 
the previous period.” 

Here, and in other extensive developments of this theory 
by Chamberlin in the ‘‘Journal of Geology,” it is definitely 
shown that the supposed decrease of carbon dioxide, re- 
garded as the chief cause of glaciation, is ascribed to in- 
creased altitude of continental areas. In other words, the 
new theory espoused by Chamberlin and Salisbury, depends 
in the same way as my epeirogenic theory, called by them 
the “hypsometric hypothesis,’”’ on exceptional continental 
elevation. Each view recognizes two periods so preémi- 
nently characterized by extensive ice-sheets, namely, the 
Permian and the Pleistocene, that we must believe, from 
the records of glaciation, that they each had much greater 
land altitude, for large parts of the continents, than any 
other period in all the vastly long ages of geologic time. 
The great epeirogenic elevations preceding and causing both 
the Permian and Pleistocene ice ages are well emphasized in 
the foregoing pages; but there we had not learned how the 


* See ‘‘Geology,’’ vol. ii, pp. 655-677; vol. iii. pp. 424-446; also 
above p. 


THE CAUSE OF THE GLACIAL PERIOD. 521 


ordinary meteorologic conditions of high land elevation were 
reinforced, in their tendency to produce ice-sheets, by the 
concomitant depletion of atmospheric carbon dioxide. Now, 
through the fruitful studies of Arrhenius, Chamberlin, and 
others, we see how the great altitude of the Continents at 
these two periods of great areas of long continued glaciation, 
so very widely separated in time and therefore remarkably 
unique and exceptional, worked in two ways, not only by 
_ the common meteorologic effects, but also by the newly 
recognized results of depletion of carbon dioxide, to give the 
marvelous glacial periods thus ending Paleozoic and Ceno- 
zoic time. 

Further studies will give the proportional effectiveness 
of these two ways by which great uplifts of the continental 
areas have induced glaciation. ‘The final theory will rest 
not less on the sagacious early views of Dana, with their 
further advocacy by Le Conte and other writers, including 
Wright and myself, than on the very helpful work of Arrhen- 
jus and Chamberlin in their added contribution to explain 
how the land uplifts accumulated ice-sheets with snowfall 
all the year upon their vast expanses. Indeed I yet think, 
that the broad view of the causation of glacial periods as 
given above was presented truly and vividly, with no more 
than the proper emphasis on the-very exceptional occurrences 
of only these two periods of general continental glaciation. 

Coming next to the great question whether the Pleistocene 
ice-sheets of North America and Europe were wholly melted 
away, as is argued by Professor James Geikie and less decid- 
edly by Chamberlin and others, we cannot adduce sure 
proofs for such conclusions from the central areas of these 
great ice-sheets on the opposite sides of the Atlantic ocean. 
The interior of New England and of British America, like 
the central parts of Sweden and Norway, have not yet 
revealed such sequence of glacial deposits and intervening 
fossiliferous beds, of somewhat temperate faunas and floras, 


022 _ THE ICE AGE IN NORTH AMERICA, 


as to give any conclusive evidences of complete departure of 
the ice-sheets and their subsequent renewal to again spread 
over nearly all of their former areas. Only in the peripheral 
parts, broadly speaking, of these two immense ice-fields, are 
proofs of successive stages of glaciation, divided by old land 
surfaces and fossil-bearing stratified beds, either of the modi- 
fied drift or of alluvial, lacustrine, or marine sedimentation. 

Minnesota, somewhat far back from our southern lim- 
its of the maximum glaciation, has well ascertained proofs 
of so great recession.of the borders of the North American 
ice-sheet as to uncover the south half of this state, succeeded 
by renewal of the snowfall and ice accumulation until the 
borders of our continental ice-sheet again reached southward 
as far as the Iowan and the Wisconsin drift. The earlier 
glaciation appears surely to have been of much longer dura- 
tion than the later Iowan and Wisconsin stages. Thus our 
Pleistocene Ice age was much diversified and even very com- 
plex, yet I would now far more confidently ascribe all our 
North American drift formations to one prolonged and con- 
tinuous glacial period, with great fluctuations of the glacial 
border, especially in the interior of the continent, than to 
regard our ice age as two-fold or three-fold, in the sense of 
having its vast ice-sheet wholly melted away, or even nearly 
so, with ensuing renewal of the snow and ice-fields. 


Geologically very rare, an ice age would scarcely be dupli- 
cated with so nearly the same limits of ice extension upon 
half of our continent. The same general conclusion is also, 
as I think, applicable to the European glaciation. Almost 
inconceivable geologic duration divided the Permian and 
Pleistocene Ice ages. In this most recent and geologically 
_ short Ice age which has ended, as I surely believe, within the 
last 10,000 to 5,000 years, at the threshold of the historic 
period, I cannot think that the stupendous climatic changes 
implied in the glaciation could permit complete repetition 
of these continental ice-sheets in America and Europe, in 


THE CAUSE OF THE GLACIAL PERIOD. 523 


each area so closely extending to nearly the same maximum 
limits in the earlier and the later parts of this Glacial period. 
It is better, until proofs are obtained in the central regions 
of the drift areas on each continent, to regard. their time of 
glaciation as one and continuous, with much areal oscilla- 
tion, such as is proverbial of weather, both during the gen- 
eral stages of growth and departure. 

My explorations of the Minnesota drift deposits, so far 
_as they appear to require great recession and later reidvance 
of the snow and ice accumulation, may be cited in the final 
reports of our state geological survey, the most notable of 
these observations being as follows, supplementing Prof. N. 
H. Winchell’s observations of an interglacial forest bed in 
Mower county and other localities of southern Minnesota.* 

1. The exceedingly interesting and elsewhere unequaled 
chains of lakes in Martin county, one of the central counties 
of our most southern tier, I can explain only by regarding 
them as proofs of a fully developed interglacial system of 
drainage running there from north to south, which became 
afterward ice-enveloped in the Iowan and Wisconsin stages 
of our Glacial period. 

2. Somewhat the same conclusion seems again enforced 
by the section of the drift close southwest of New Ulm, in 
Brown county, about 40 miles north of these chains of lakes. 

3. In the northern part of Chisago county, on the east 
side of Minnesota, Rushseba township, in which Rush City 
is situated, about 50 miles north of St. Paul and Minne- 
apolis, has a considerable tract,§ some 5 or 6 miles long and 
of nearly as great width, where reddish-modified drift, spread 
by streams flowing down from the receding northeastern 

*See below p. 605. 

t ‘‘Geology of Minnescta,”’ vol. i, 1884, pp. 479-485, with the map 
facing page 472. 

t Ibid, vol. i, pp. 581-3, with section, and with map facing p. 562. 


§ ‘Geology of Minnesota,” vol. ii, 1888, pp. 409-415, 417, 418, the 
last giving the record of that well, with the map facing page 399. 


524 THE ICE AGE IN NORTH AMERICA. 


lobe of the ice-sheet, forming for a time a land surface which 
bore timber, was subsequently overspread by an ice-lobe 
whose current was from the northwest to the southeast and 
east. The overlying yellowish gray till, spread as a continu- 
ous and nearly uniform bed only ten to twenty feet thick 
and forming a nearly level expanse of so much extent, at 
least 5 miles in diameter, has plentiful limestone fragments 
from the northwest, being thus in remarkable contrast with 
the red till deposits lying beneath the gray till in that region, 
which came from the northeast and therefore has no lime- 
stone. A well’ on this area encountering peat and decaying 
fragments of wood in a water-deposited clay beneath the 
gray till and at the top of the older underlying modified drift 
gravel and sand, testifies that this was a land surface with 
peat and forest trees, previous to the-very latest glaciation 
which brought the yellowish gray till.* 

4. On the southern part of the area of the Glacial Lake 
Agassiz, at Barnesville in Clay county, about 190 miles 
northwest of the Twin Cities (St. Paul and Minneapolis), 
a well penetrates twelve feet of till, and next beneath, in the 
bottom of the well, went one foot into quicksand, ‘“‘contain- 
ing several branches and trunks of trees, thought to be tam- 
arack, up to eight inches in diameter, lying across the well, 
which, together with the inflow of water, prevented farther 
digging.”’ This well is on the till area of the village of Barnes- 
ville, about eighty feet below the highest beach of Lake 
Agassiz, which passes from south to north about three miles 
east of this village. At the time of my survey of that region 
and when this volume was published, in 1888, I considered 
the occurrence of this interglacial bed within the area of the 
glacial lake as good evidence that the ice-sheet in that inter- 
glacial stage was melted back at least so far as to give out- 
flow into Hudson Bay from the Red River Valley, draining off 
the interglacial forerunner of Lake Agassiz. ‘Subsequent 
studies and general reasoning lead me, however, now to hold 

* See above p. 184. 


THE CAUSE OF THE GLACIAL PERIOD. 525 


the different view that probably the earlier interglacial lake 
in this valley may have even cut its channel of southern out- 
let, at the site of Brown’s Valley, to a lower level than the 
well in Barnesville, or that the attitude of the land then 
was unlike what it now has, having then such an ascent from 
south to north that the Barnesville locality in that inter- 
glacial time was above the general surface of the region at 
Brown’s Valley, into which the River Warren, outflowing 
from Lake Agassiz, cut its deep continuous valley. So I 
now think that we have there, in the section of this well, 
only evidence of an ice retreat (that is, a departure of the 
outer part of the ice-sheet) so far north as to that region, 
about halfway between the south and north boundaries of 
this state.* My numerous papers show how, as I think, 
good forests and other luxuriant vegetation may have 
flourished near the border of the ice-sheet, accompanying 
the recession of that border. 

The questions are sure to be asked: Why is the boundary 
of the glaciated region in the United States so irregular ? 
What was the cause of its withdrawing so far north in western 
New York, and of its sudden bend to the south in eastern 
Ohio, and of its lobe-like projections in southeastern Indiana 
and southern Illinois? And what was the cause, at a later 
stage, of the lobate contour of the moraines west of Lake 
Michigan in Wisconsin, Iowa, Minnesota, and Dakota? These 
questions we can only answer by saying that the distance to 
which the great American ice-sheet penetrated the southern 
latitudes was evidently not dependent, to any great extent, 
upon the elevation of the land over which it was compelled to 
move. The ice did not uniformly move farther south where 
there was a depression of the land, and the boundary does 
not ordinarily retreat to the north on account of the higher 
elevations opposing its progress. South of New England the 


* Geology of Minnesota, vol. ii, pp. 661-2, and 668; with the map 
facing p. 656. 


526 THE ICE AGE IN NORTH AMERICA. 


glacial front was at the sea-level, and the ocean itself may 
have kept it from advancing farther. In Pennsylvania the 
boundary-line crosses the Alleghany Mountains diagonally, 
being nearly as high on Pocono Mountain, in the’eastern part 
of the State (about two thousand feet), as in the southwestern 
part of New York, where it is sixty or seventy miles farther 
north. In Ohio the highest portion of the State is in Logan 
county, almost directly north of Ripley, in Brown county, 
the most southern point reached in that. State. The unglaci- 
ated portion in southern Indiana, projecting about seventy 
miles northward into the glaciated region, is indeed some- 
what higher than the land on either side, but nowhere is its 
elevation greater than that of the larger portion of Ohio. 
The farthest extension of the ice in Illinois is closely coinci- 
dent with the trough of the Mississippi Valley, and westward 
of the Mississippi River the edge of the ice withdrew farther 
and farther north pretty nearly in proportion to the increas- 
ing elevation of the country, until, at Sim’s Station, in the 
vicinity of Bismarck, Dakota, it is nineteen hundred and sixty 
feet above tide, and continues thence to ascend northward to 
a height of three or four thousand feet in the upper valley of 
the Saskatchewan. | 
There is, thus, a general conformity in its southern exten- 
sion to the valley of the Mississippi. The ice of the Glacial 
period as a whole did, indeed, move down that great valley, 
and its most southern point is in the middle of it, where it 
it is not more than five hundred feet above the sea; but it is 
evident that the total width of the southern portion of this 
ice-sheet is so great, and the slope itself so slight, that this 
depression could not have been the main cause of the great 
extension to the south in Illinois. The width of the glaci- 
ated area from southern Ohio to eastern Kansas, on the thirty- 
ninth parallel, not far from the extreme limit of glaciation, 
is nearly a thousand miles. The cause, therefore, of the lo- 
bate character of the southern boundary must, in all proba- 
bility, be sought in the irregular areas of excessive snow-fall 
existing to the north during the advance and continuance of 


THE CAUSE OF THE GLACIAL PERIOD. 527 


the Glacial period. From a glance at the map it would seem, 
therefore, that the greatest area of snow-fall was somewhere 
in the vicinity of Lake Superior, and that a secondary area of 
large snow-fall was in the vicinity of Labrador; for the south- 
ern boundary of the glaciated region consists essentially of the 
ares of two circles whose centers would fall within the areas 
indicated. | 

In speaking of these two areas as centers of radiation for 
the glaciers of the great Ice age in North America, it is not 
affirmed that the movement received no impulse from still 
farther north. It is not improbable that the upper portion 
of Baffin Bay was filled and crossed by the glaciers still 
lingering over the continental area of Greenland, and that 
this Greenland ice aided in the movement which covered the 
northern part of the United States with its icy mantle. But 
it was probably by reaction rather than by direct action that 
aid came from that quarter. The accumulations to the north 
prevented an outflow in that direction, and so compelled a 
southerly movement from the vicinity of the Laurentian 
highlands. It is not, however, probable that any Greenland 
ice ever reached the United States. None of the bowlders 
so common in the United States are, so far as known, more 
than a few hundred miles distant from their parent ledges. 
There was doubtless all the while an ice-stream down Bat- 
fin Bay toward the Atlantic Ocean, with a movement into 
it from both sides. But even if this were not the case, the 
areas south of Hudson Bay and in Labrador would still be 
the predominant influence in determining the southern out- 
line of the glacial boundary. The snow that piled up from 
year to year over those centers would be compelled to move 
off in the lines of least resistance. Now, ice can be an ob- 


struction to other ice as well as to water; and what the . 


Greenland glacier probably did was to close up the upper 
portion of Baffin Bay, so that the excess of snow-fall over 
the subcenter referred to as north of Lake Superior could 
not move off to the northeast, but was compelled to spend 
all its force in a southerly movement. It is evident also that 


528 THE ICE AGE IN NORTH AMERICA, 


every subcenter where the snow-fall was larger than the 


average would, to some extent, make its influence felt upon 
the shape of the margin. 

Here is a field for the mathematician. When the prop- 
erties of ice are more fully understood from experimental 
investigations, and the laws of its fluidity brought under 
mathematical formule, it will doubtless be possible, from a 
study of the contour of the glacial boundary, to calculate the 
position of all the principal areas of largest precipitation 
during the Glacial period. 

Those remarkable lobe-like projections in southern Ohio 
and Indiana, for example, indicate subcenters of accumu- 
lated ice not far back from the margin. The still more 
remarkable prolongation of the loops in the kettle-moraine 
in Wisconsin, and its extension through the States farther 
west, point, as President Chamberlin sagaciously and cor- 
rectly supposes, not merely to greater snow-fall over the 
regions from which the ice-emovement radiated, but to the 
conservative influence of the deeper valleys and depressions 
to the north, which were filled with ice. These loops of the 
kettle-moraine sustain a remarkable relation to the valley of 
Green Bay, and to the northeast and southwest axis of Lake 
Superior, while the ice-lobe which occupied the valley of the 
Minnesota and extended to the center of Iowa is evidently 
related to the great valley of the Red River of the North. It 
is not improbable that the depth of ice in such a depression 
as Lake Superior would, by its very thickness, tend for a long 
time to increase the snow-fall over its own area, and in other 
ways to resist the antagonistic agencies which were gradu- 
ally driving the ice-front back to the north. The driftless 
area of southwestern Wisconsin is situated just where it es- 
capes these several ice-movements dominated by the depths 
of Lake Michigan and Lake Superior, and it is to this day— 


as Professor Dana has pointed out—a region of light pies | 


tation. 
If this discussion of the cause of the Glacial period 
seems unsatisfactory, the justification is that the present 


‘ ee 


THE CAUSE OF THE GLACIAL PERIOD. 929 


knowledge of the whole subject is in an extremely unsatis- 
factory condition; and in this, as in other things, the first 
requisite of progress is to squarely face the extent of our 
ignorance upon the question. The causes with which the 
glacialist deals are extremely complicated, and yet they are 
of such a nature as to invite investigation, and to hold out 
the hope of increasing success in mastering the problem. 
There is opportunity yet for some Newton or Darwin to 
come into the field and discover a clew with which success- 
fully to solve the complicated problem which has so far baf- 
fled us. To the genuine investigator it is a source of inspi- 
ration rather than of depression to have such an untrodden 
field before him. 

Conciusion.—Geology is pre-eminently a terrestrial sci- 
ence, and there is danger of a misdirection of effort when 
the geologist forms an alliance with the astronomer. Astro- 
nomical data are so largely theoretical, and the quantities 
which the astronomer multiplies are often so nearly infinitesi- 
mal, that quantitative error is in peculiar danger of becom- 
ing enormous in large calculations. Hence, we can not count 
it altogether an advantage that astronomical speculation has 
been so rife during the past few years in determining the 
causes and the chronology of the Glacial period. 

Of the various cosmical theories to account for the Gla- 
cial period, that of Mr. Croll is by far the most plausible and 
interesting. It must be admitted that his data concerning 
the various distances at which the earth is, found from the 
sun during the winters of different periods, and concerning 
the periodical variations in the length of the winters, rest 
upon well-ascertained facts. It is no doubt true that about 
one hundred thousand years ago the winters were at times 
several days longer than now, and the northern hemisphere 
was receiving daily considerably less heat than now, since it 
was several millions of miles farther away from the sun. 

But the distribution of the earth’s heat by winds and 
oceanic currents is a subject concerning which much less is 
known. The phenomena presented in a hot-house are puz- 


530 THE ICH AGE IN NORTH AMERICA. 


zling. The heat of the sun goes through the glass, but can 
not readily get out again. It is well known, also, that a 
slight increase of moisture in the atmosphere, or a slight 
film of cloud over the sky, prevents a frost. The real prob- 
lem lies, therefore, in the meteorological field. Now, during 


Mr. Croll’s “ aphelion ” winters, the summers are in “ perihel- 


ion,” and the summer heat in this hemisphere while in peri- 
helion is more intense than at other times. In fact, the 
earth receives at all times the same absolute amount of heat 
from year to year. Thus, we can not avoid the conclusion 
that the predominant influence in climate may consist in the 
power of moisture-laden atmosphere to retain and transport 
the heat, thus determining its distribution. As a matter of 
fact, we find that the equator is not so hot as theoretically it 
should be, and the arctic regions are by no means so cold as, 
on Croll’s theory, they ought to be. . The difference between 
the mean temperature on the equator and that at the coldest 
point on the sixty-seventh parallel is really only about 75° 
Fahr.; whereas, if the temperature at these points were pro- 
portionate to the amount of heat received from the sun, the 
difference would be 172°. Such facts as these lead meteor- 
ologists to regard Mr. Croll’s theory with much less favor 
than formerly. nee 

But the glacialist is not so much concerned to know the 
ultimate cause of the Glacial period.as he is to collect the 
facts which characterize the period. The truth is, that the 
meteorological forces of Nature are so powerful and complex 
that there is an embarrassment of riches in the field of gla- 
cial theory. It is easy to see that a slight increase of snow- 
fall over the Alps would cause a permanent enlargement of 
all the glaciers of Switzerland, and threaten every interest of 
that republic, and perhaps of central Europe; for the ulti- 
mate effects of a climatic disturbance in one such center can 
not well be estimated. 

Much light upon the condition of things during the Gla- 
cial period in America must yet come from a careful study 
of the lobate contour of the terminal moraines. The shapes 


j ut 
— Ss ee 


THE CAUSE OF THE GLACIAL PERIOD. 531 


of these moraines, coupled with what may yet be learned 
concerning the nature of ice and concerning the shifting 
course of the atmospheric currents, will, in all probability, 
eventually furnish the data for the solution of the question 
of the true cause of the Glacial period. A fair field here 
invites the active and prolonged attention of some future 
meteorological Darwin or Newton, and promises immortality 
such as they have attained. 


CHAPTER xk 
THE DATE OF THE GLACIAL PERIOD. 


Two causes have combined in recent years to favor erro- 
neous calculations concerning glacial chronology. Of these, 
the first has been the almost unquestioned acceptance of the 
astronomical theory subjected to examination in the preced- 
ing chapter. If Mr. Croll’s theory of the cause of the Gla- 
cial epoch is correct, then we should no longer speak of an 
ice age, but of a succession of such ages, whose dates could be 
readily determined from a table showing the periods of high- 
est eccentricity in the earth’s orbit. According to this table, 
the modern period most favorable to the production of a 
glacial epoch began about two hundred and forty thousand 
years ago and ended about seventy thousand years ago. The 
whole intervening time was one of high eccentricity, when, 
during the recurring intervals in which the winters occurred 
at aphelion, the excess of winter over summer ranged from 
fourteen to twenty-six days, and the intensity of the heat 
received from the sun during those aphelion winters was ten 
per cent less than at the present time. During the time in- 
tervening between seventy thousand and two hundred and 
forty thousand years ago, there occurred, therefore, according 
to this theory, a succession of glacial and interglacial periods 
in which geologists and archzologists are invited to distrib- 
ute their remarkable discoveries concerning glacial man. 
Undue confidence in this theory has had no small influence 
in diverting attention from the more legitimate lines of in- 
vestigation. 

A second source of error has been an incorrect interpre- 


‘plage <A 


THE DATE OF THE GLACIAL PERIOD. 533 


tation of Lyell’s principle of uniformity in Nature’s opera- 
tions. This has led to an exaggerated estimate of everything 
pertaining to geological time. There is a prevalent popular 
impression that all geological events happened a great while 
ago. This impression arises largely from the imperfect ap- 
prehension of the extent to which changes are now going on 
in the world. In reality, however, Lyell’s greatest service 
consisted in quickening our conception of the instability of 
the present condition’ of things, and of the intensity of 
present natural forces. He riveted the attention of his 
readers upon the cumulative effect of such earthquakes as are 
now of daily occurrence, and occasionally of enormous influ- 
ence, and continually reminded them of the frequency and 
intensity with which new volcanoes are now from time to 
time bursting forth. Continuity, therefore, rather than uni- 
formity, is the word which most properly expresses the prin- 
ciple underlying the theories of this great geologist. A pe- 
rusal of his works makes it evident that evolution, and not 
dull repetition, characterizes the processes of Nature. There 
is therefore really nothing in Lyell’s working principle to 
raise any antecedent presumption in favor of an extreme 
antiquity for the Glacial period. 

On the contrary, the present tendency, both among as- 
tronomers and geologists, is to diminish estimates of geologi- 
cal time in almost every period. The hundreds of millions 
of years claimed, not long ago, as necessary for the deposition 
and metamorphism of the geological strata, and for the ele- 
vating and eroding forces to produce the present contour of 
the earth’s surface, have on geological evidence been reduced 
to much more moderate limits. Thirty million years is now 
shown to be ample for the deposition, by forces still in op- 
eration, of all the sedimentary strata of which we have 
knowledge. At the same time the astronomers aflirm that 
life can not have existed on the earth earlier than twelve 
million or fifteen million years ago.* Before that period 


* See Newcomb’s “ Popular Astronomy,” pp. 513-519. 


004 THE ICE AGH IN NORTH AMERICA. 


the radiation of the sun’s heat was so intense that life a 
have been impossible upon our globe. 

But he who pauses to reflect upon how long a period one 
million years is, and takes the pains to multiply the annual 
changes of the present time by that number, will not feel 
cramped by the limits which astronomers are now setting to 
geological time. In this general shortening of our concep- 
tion of geological periods, the evolutionists also find no small 
relief in the more moderate estimates made concerning the 
date of the close of the Glacial period; for it is very clear 
that the changes in species since the great Ice age are trifling. 
The flora and fauna of the world during the Glacial period 
were essentially the same as those of the present time. Even 
man is believed to have been an inhabitant of America, as 
well as of Europe, before the ice had withdrawn from the 
head-waters of the Delaware River, and from the mountains 
of Scotland and the north of England. If these changes in 
the organic world have been so slight since the Glacial epoch, 
it follows that, the further back that period is placed in time, 
the greater are the difficulties of the evolutionists. The 
more the evolutionists are limited. in time by the astrono- 
mers, the more do they need a rapid rate of change as the 
basis of their calculations. If, therefore, the Glacial period 
should prove to have ended only ten thousand years ago in- 
stead of seventy thousand, the Darwinian would be relieved 
from no small embarrassment. Thus, so far as there is likely 
to be any odium theologicum in the ease, the desire to sup- 
port a short biblical chronology and the counter-desire to dis- 
credit Darwinism, and vece versa, may be left to counteract 
each other. 

In view of the doubt expressed in the preceding chapter 
concerning Mr. Croll’s theory, it does not seem proper for 
geologists to rest satisfied with mere astronomical calcula- 
tions respecting glacial chronology. We may, therefore, be 
permitted to turn to the more congenial task of considering 
the direct geological evidence bearing on the question. In 
this field there are three classes of facts to which we can 


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536 THE ICE AGE IN NORTH AMERICA. 


confidently look for light: 1. The amount of erosion and 
' disintegration which has occurred since the Glacial period. 
2. The extent to which lakes and kettle-holes have been filled 
with sediment. 3. The apparent freshness of organic re- 
mains in glacial deposits. 

Beginning with the extent of erosion which has taken 
place since the withdrawal of the ice, our attention is, natu- 
rally enough, directed first to the gorge below the Falls of 
Niagara. How this comes to be a glacial chronometer has 
already been seen.* The old outlet of Lake Erie, which 
must have existed as the result of preglacial erosion, was 
filled up during the great Ice age, and the Niagara River is 
the outlet of the pond thus created. Originally the water 
plunged over the escarpment at Queenston, about seven 
miles below the present cataract. This escarpment is formed 
by an outcrop of a thick deposit of Niagara limestone, the 
summit of which is about three hundred feet above the level 
of Lake Ontario. This is underlaid by a softer rock, which 
is more rapidly disintegrated than the upper strata; hence 
the upper strata always project beyond the lower, and every- 
thing favors the continuance of the cataract at the head 
of the gorge as it wears back. The problem is to’ de- 
termine how long the Niagara River has been in wearing 
out the gorge between Queenston and the present cata- 
ract. The solution of that problem will furnish an answer 
to the other question, How long has it been since the ice- 
barrier across the valley of the Mohawk was removed, so 
that the dammed-up waters of Lake Ontario and Lake 
Erie would subside sufficiently to permit the formation of 
the cataract at Queenston and the commencement of erosion 
in the present gorge? The problem is comparatively simple, 
and its bearing upon the date of the Glacial period is clear. 

The Falls of Niagara have receded about seven miles. 
The conditions have been from the first so nearly uniform 
that the present rate of erosion can not differ largely from 


* See chapter xii, p. 303 e¢ seq. 


— 


THE DATE OF THE GLACIAL PERIOD. 037 


the average rate. There is some evidence that a part of the 
work above the Whirlpool had been done by a local stream 


WAurrlp oob 


which formerly passed from the Whirlpool westward to St. 
Davids, since there is no doubt of the existence of a filled-up 
preglacial channel running from the Whirlpool to St. Day- 
ids. But the evidence that this channel extended above the 
Whirlpool toward the present cataract is so imperfect that we 
must leave it out of the question, and take the whole length 
of the gorge from Queenston to Niagara as our dividend. 
The problem remaining is to find the rate of recession, and 
this will serve as a divisor. 

The comparative youth of the Niagara gorge is evident 
from the present condition of its mouth at Queenston. This 
is narrow, and its walls abrupt; but it is well known that, by 
the inevitable action of natural forces, the mouth of a river- 
gorge must become, in process of time, very much enlarged, 
since from the beginning its sides have been exposed to 
the eroding action of the elements and to the undermin- 
ing action of the river. In the unglaciated region the 
mouths of such gorges are universally wide and V-shaped, 
and the banks much obscured at the bottom by the accumu- 
lation of débris. In this respect the mouth of the present 
gorge at Queenston is in striking contrast with that of the 
old gorge which opened at St. Davids. As will be seen by 
reference to the map, this, though narrower where it left 
the Whirlpool than the present main gorge below the Whirl- 


Rk I os [R= 
SS BN 

\\\\ 
N jagara \\ 


aS 


—Z 
LE 
Z Fa 


pwr 


Gasp 
—FRIVER 


Queenston , 


7D 


SSS, 


Z 


(q hirlpool 


SCALE OF MILES 


0 4 1 


; \ ae \ 
l ‘iagar: ) \ 
Struthers § Co., Engr’s, N.Y. singel Scanct hs a . 


Fie. 134.—Map of the Niagara River below the falls, showing the buried channel from 
the whirlpool to St. Davids. Small streams a, 0, c, fall into the main gorge over a 
rocky escarpment. No rock appears in the channel at @, but the rocky escarpment 
reappears at e. 


THE DATE OF THE GLACIAL PERIOD. 539 


pool and not over half as long, is still at its mouth by St. 
Davids several times as wide as that of the present Niagara 
gorge at Queenston. 

Coming to the main question, and taking the whole of 
the gorge from Queenston to the present cataract as the 
work done by the Niagara River since the ice-barrier in the 

valley of the Mohawk gave way, the problem is to find the 
rate of recession. Until very recently the estimates of this 
rate have been scarcely more than mere guesses. The emi- 
nent French glacialist Desor thought it could not have been 
greater than one foot in a century, which would place the 
beginning back 3,500,000 years. In 1841 Sir Charles Lyell 
and Professor James Hall examined the gorge together ; and 
Sir Charles, in his lectures in Boston before the Lowell Insti- 
tute soon after, estimated that the maximum rate of reces- 
sion could not be greater than one foot a year, which would 
fix the minimum date of its beginning at about thirty-five 
thousand years ago. On the contrary, all the guides of that 
period who had observed the falls for many years, were con- 
fident that the rate of recession was as much as two feet a 
year ;* while Mr. Bakewell, an eminent English geologist, who 
had given much personal study to the question, estimated 
that, for the forty years previous to 1830, the rate of recession 
had been about three feet a year. Mr. Bakewell’s son care- 
fully reviewed the phenomena again in 1846, in 1851, and in 
1856, and found no occasion to revise his father’s estimate.t 

To furnish the basis for more accurate calculations, Pro- 
fessor James Hall had a map of the falls made in 1842, from 
a trigonometrical survey, so that there should be a fixed 
standard for future comparison. Within the past few years, 
accurate surveys have ayain been made, both by the geolo- 
gists of the State of New York, and by members of the 
United States Coast Survey. In 1886 the American Associa- 
tion for the Advancement of Science held its annual meeting 


* Lyell’s ‘‘ Travels in America ”’ (first series), vol. i, p. 27. 
+ “ American Journal of Science,” vol. xxiii, 1857, pp. 87, 93. 


540 THE ICE AGE IN NORTH AMERICA. 


at Buffalo and great interest was naturally centered upon this 
question of the rate of the recession of the falls. Mr. G. K. 
Gilbert, of the United States Geological Survey, whose au- 
thority is unsurpassed on such subjects, gave it as his conclu- 
sion that the “‘maximum length of time since the birth of the ~ 
falls, by the separation of the lakes, is only seven thousand 

years, and that even this small measure may need significant 

reduction.” At the same time Mr. R. S. Woodward,* of 

Washington, made a new survey, and gives the results defi- 

nitely as follows: The length of the front of the Horseshoe Fall 

is twenty-three hundred feet. Between 1842 and 1875 four 
and a quarter acres of rock were worn away by the recession 

of the falls. Between 1875 and 1886 a little over one acre 

and a third disappeared in a similar manner, making in all, 

from 1842 to 1886, about five and a half acres removed. 

Subsequent surveys have amply supported these conclu- 
sions. From the survey made in 1905, by Mr. Carvel Hall, 
state engineer of New York, it appears that the recession of 
the Horseshoe Fall (which is where the principal volume 
of water descends) during the sixty-three years between 
1842 and 1905 was 333 feet, or at the rate of 5.3 feet per 
annum : : 

The foregoing estimates concerning the recession of the 
Niagara gorge assume a uniform rate, and that all the work 
has been done since the glacial period. As to the first of 
these assumptions, Dr. Julius Pohlman,t of Buffalo, adduces 
some evidence to show that the present course of the Niagara 
from the Whirlpool to Queenston follows an old line of drain- 
age, in which a small stream had eroded a shallow valley 
previous to the ice period, and thus, by reducing the thick- 
ness of the upper layer of hard limestone along its course, 
had greatly facilitated the work of recession, when the whole 
torrent of Niagara began to pour over the escarpment. Dr. 
Pohlman has also greatly increased our conception of the 
work already done before the Glacial period by the stream 
which had its exit from the Whirlpool to St. Davids. This 


* Report in ‘‘Science,’’ September 3, 1886. | 
t ‘Transactions of the Amer. Institute of Mining Engineers,’’ 1888. 


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00> 668 008 oot 6 069 003 
—_—_S——oSSS———Ssr - 


4333 JO 31V0S 


oN eT? STs 


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042 THE ICE AGE IN NORTH AMERICA. 


stream, composed of the waters of the Tonawanda and Chip- 
pewa Creeks, was of considerable extent, and by its action 
had doubtless predetermined the course of the present river 
above the Whirlpool, and may actually have worn a consid- 
erable part of the present gorge above the Whirlpool. 

Another element of uncertainty, which has led Mr. Gil- 
bert and others to retract their former views, or at least to 
hold them in suspense, relates to the variations of the water 
supply since the beginning of the erosion. 

It should, however, be noted that the erosion at Niagara 
began long before the close of the Glacial period, namely 
when the ice had melted off from the Mohawk Valley so as 
to permit the drainage to take that course to the Hudson, and 
lower the level of the existing glacial lake to that of the col 
at Rome, N. Y. This would permit erosion to begin at the 
mouth of the Niagara gorge, long before the ice had retreated 
from the lower St. Lawrence Valley and from Canada in 
general. 

A most interesting state of things respecting the varia- 
tions of the water supply at Niagara comes to light in connec- 
tion with the differential northerly depression of land during 
the Glacial period, and its re-elevation after the disappearance 
of the ice. From the fact that there was a northerly depres- 
sion of 600 feet at Montreal, and presumably as much in the 
northern basin of the Great Lakes, it follows that upon the 
melting off of the ice from the Ottawa Valley, and from the 
water parting between it and Lake Huron, the drainage might 
for the most part be diverted in that direction, leaving the 
Niagara with only that supply of water which would be fur- 
nished by the local basin about the east end of Lake Erie. In 
1892, I was sofortunate as to find clear evidence of this outlet 
leading across from Lake Nippissing, past the town of North 
Bay, into the Mattawa River and thence into Ottawa at the 
town of Mattawan. The col at North Bay is less than 100 
feet above the present level of Lake Huron, while the evi- 


THE DATE OF THE GLACIAL PERIOD. 548 


dences of a post-glacial flow of water in enormous quantity are 
perfectly clear. At Mattawan there is an enormous delta 
of bowlders where the valley of the Mattawa joins that of the 
Ottawa. Many of the bowlders are several feet in diameter, 
and they are all waterworn. Moreover, the bowldery delta 
has been pushed out into the Ottawa Valley so as to dam the 
river and create a deep lake-like expansion above and a long 
series of rapids below. In confirmation of the theory that 
there was a flow of water through this channel for a consider- 
able time Mr. Taylor found miniature pot-holes worn in 
some of the large bowlders of the delta terrace at Mattawan. 

Of course while the drainage of the Upper Great Lakes 
was diverted around to the St. Lawrence by way of the Ottawa 
Valley, the recession of the Niagara gorge was practically at 
a standstill. It is important therefore to ascertain how long 
a time this continued. Calculations upon this point will 
largely depend upon the question of how rapidly the post- 
glacial re-elevation of the region went on. Happily we have 
much evidence upon this point, all of which indicates a rapid 
rate as compared with that which is now going on. 

The most important evidence comes from Dr. Upham’s 
study of the shore lines of the glacial Lake Agassiz which 
spread over the valley of the Red River of the North (see 
page 401). Thistemporary lake covered more than 100,000 
square miles and its shore lines are easily traced for hundreds 
of miles, like railroad embankments, across the prairie coun- 
try of that region. There are several series of these shore 
lines, at successively higher levels. But at the head of the 
valley where the outlet was through Big Stone and Traverse 
lakes into the valley of the Minnesota River, the beaches are 
approximately at the same level. On proceeding northward, 
however, while the lower beach remains nearly horizontal, the 
upper one rises until in latitude 51° 52,’ 200 miles north of 
the international boundary, it is 400 feet above the lower 
shore line. Thus it appears that during the existence of this 


F 1a. 136—Exposure of Niagara shale in Niagara gorge. (Photo by Dutton). 


14-2 __191_ 57 140 
~ 41 +3 NIAGARA Soca Wes Aa 
Niche wai) amo resort 4 S 
i BBE: 
i] t ‘ ‘ 4 
naan ‘ ' 
DTT TE ry CLInTON { } sy FA 


=< 


Coty: MEDINA (01 pet 


o 
eo 


ee eo 


Fie. 137—Diagram showing small amount of actual enlargement of the mouthof Niagara 
Gorge at Lewiston. 


THE DATE OF THE GLACIAL PERIOD. 045 


lake there was a rise of 400 feet in the northern part while 
there was a rise of but a few feet at the southern end. 

These facts give us a chance to estimate the rate of this 
differential rise in the land lying north of the glacial border 
which has been going on up to the present time, and thus 
furnishes data from which to calculate the length of time dur- 
ing which the depression at North Bay was sufficient to divert 
the water of the Upper Great Lakes from Niagara. From the 
data collected by Dr. Upham during his investigations of 
Lake Agassiz he concludes that its entire existence could not 
have been more than 2,000 years and probably was not more 
than 1,000 years. 

The facts upon which Dr. Upham relies, are: 1. The small 
size of the deltas deposited on the margin of the lake by the 
great rivers entering from the west; 2. The small size of the 
ridges themselves; 3. The limited extent of the dunes about 
the southern end of the lake. 

1. The most important rivers which formed deltas in the 
lake are the Cheyenne, the Assinniboineand theSaskatchewan, 
which all come in from the region to the westward which was 
free from ice during the greater part of the time of the exist- 
ence of the lake. The gradient of these streams is rapid, and 
the supply of sand and gravel within their reach is abundant. 
Yet their delta deposits at the level of the beaches is small, 
and entirely inconsistent with the continuance of the lake for 
more than 1,000 or at most 2,000 years. 

2. Theshore lines, or beaches, are very much smaller than 
those around Lake Erie, which, as we elsewhere show, could 
not have been more than 2,000 to 3,000 years in forming. 

3. The dunes at the south end are not over one-tenth the 
size of those at the south end of Lake Michigan, which demon- 
strably were not over 10,000 to 15,000 years in forming. 

In explanation of this point it is necessary to call attention 
to the facts concerning the dunes south of Lake Michigan. 
These are very prominent features along all the railroads 


ag { 


Fic. 1388—Photograph looking north-west towards St. Davids showing the excessive ene 
largement of themouthofthe preglacial channel. 


ee 3 


ee 


Fie. 139—Section, drawn to equal vertical and horizontal scale, showing enlargement of 
Niagara gorge on the east side at its mouth at Lewiston: 1, Niagaralimestone, 
20 to 30 feet ; 2, Niagara shale, 70feet ; 3, Clinton limestone, 20 to 30 feet; 4, Clinton 


and Medina. shale, 70 feet; 5, Quartzose Medina sandstone, 20 to 30 feet; 6, softer 
Medina sandstone, 120 feet above water level. 


THE DATE OF THE GLACIAL PERIOD. 547 


entering Chicago from the east, but theyare limited in extent, 
and are in process of formation at the present time, the rate 
of which can be approximately calculated. Lake Michigan 
is now a closed body of water at the south end, and it is eating 
into its western banks and bluffs at a rapid rate, the shelf 
eroded by the waves since the departure of ice from its central 
depths being about seven miles wide. The shingle, gravel 
and sand derived from this erosion of the banks is carried along 
the west shore southward past Chicago to the south end of 


ITE: j 


i 
+... 

On ne 
- 


Fig. 140—Hypothetie hydrography of the Great Lakes at a date after the melting of the 
great glacier from the St. Lawrence Valley. 


the lake, where it is taken up bythe wind and blown outward 
to form the dunes which are now so prominent a feature in 
the landscape. It has been important for various reasons to 
learn how fast the sand is being carried past the Chicago 
front, so that engineers have made very careful estimates. On 
comparing the rate at which the material is being carried 
past Chicago, with the total amount of sand contained in the 
dunes at the south end of the lake, it appears that the process 
cannot have been going on more than 10,000 years. 

Now, since Dr. Upham estimates that the dunes at the 
south end of glacial Lake Agassiz are not over one-tenth the 


548 THE ICE AGE IN NORTH AMERICA. 


size of those south of Lake Michigan, those on Lake Agassiz 
would have been formed in about 1,000 years. Hence this 
differential northerly elevation of land over the basin of 
Lake Agassiz to the extent of 400 feet must have taken place 
within that limited period. Such being the ascertained rate 
of elevation in the Red River Valley, it is altogether probable 
that the rise in the land at North Bay would not occupy a 
much longer period, for the conditions with respect to the 
glacial ice and its recession are nearly alike in both regions. 
In addition to this evidence adduced by Dr. Upham, I had 
long before called attention to the small amount of erosion 
which had taken place in the delta at Mattawan since the 
glacial outlet there had been closed. 

Another independent line of evidence indicating the 
brevity of the past life of the Niagara gorge is drawn from a 
study of its width at the mouth. In 1898 and 1899 I was 
deputed by the New York Central Railroad to study the lower 
part of the eastern side of the gorge, to shed what light I 
could upon the stability of the conditions surrounding the 
road bed built along the face of the gorge. Every facility for 
examination and measurement was granted me. Briefly, the 
results were as follows: the width of the river at the mouth of 
the gorge is 770 feet, which is practically the original width of 
the gorge, for the débris falling down has prevented the stream 
from enlarging its channel at the base of the cliff. 

Assuming that the cliff was originally perpendicular, 
measurements showed that the strata at the summit had 
receded on the east side only to the extent of 388 feet, making 
the total width of the top of the gorge at the mouth 1,553 
feet, on the supposition that the west side had been worn 
away as fast as the east side had been. But various irregulari- 

ies prevented as accuratemeasurementsonthatside. Nowthis 
subaérial erosion of 388 feet from the top of the gorge on one 
side indicates the removal of an inverted section of the face 
of the gorge, with a base of 388 feet and a height of 340 feet, 


of New York Central Railroad. 


st side of Niagara Gorge, at its mouth; showing course 


X—Section on ea 


PLATA 


f= 


of 


AY 


THE DATE OF THE GLACIAL PERIOD. 549 


the height of the cliff at this point. If the subaérial erosion 
of the face of the gorge proceeded at the rate of one-quarter 
of an inch per annum, the material would have been removed 
in less than 10,000 years. That this rate is not excessive 
was shown both from the vast amount of débris that is now 
annually precipitated upon the railroad track, and from actual 
measurements of the extent to which the hard strata of lime- 
stone had been undermined since the track was laid, in 1854, 
when it was found that the underlying Clinton and Niagara 
shales had worn away more than three inches a year, leaving 
the harder strata to project from thirteen to fourteen feet. 
As illustrating the rapidity of erosion from the sides of the 
gorge it is in point to remark that in 1898 there fell off at one 
time from the face of the cliff on the east side of the Whirlpool, 
100,000 tons of rock, whereas the amount which we have 
supposed to fall away annually from the one mile and a half 
measured by us is only 1,237 tons. From these facts it is 
evident at once that the erosive agencies tending to give a 
V-shape to the mouth of the gorge could not have been in 
operation much more than 10,000 years. To suppose they 
had been at work for 30,000 or 40,000 years, as many still 
try to do, involves an absurdly low rate of activity on the part 
of the forces which have been constantly at work. 

Something more also needs to be said about the significance 
of the preglacial channel leading from the Whirlpool to St. 
Davids. In the first place it should be noted that the mouth 
of this gorge is very wide, being in fact nearly a mile in width, 
thus indicating great age. In the second place, the depth of 
the Whirlpool (150 feet), and the width of the head of the St. 
Davids gorge (fully twice that of the Niagara gorge immedi- 
ately above and below), point to an extreme age. It seems 
altogether probable, indeed almost demonstrable, that the 
St.Davids’ gorge had been worn back by a small stream formed 
by the junction of two streams, one coming along the line of 
the present gorge through the Whirlpool Rapids, and the 


550 THE ICE AGE IN NORTH AMERICA. 


other coming from the north from asmall water shed bounded 
by the escarpment at Queenston. As the gorge both above 
and below the Whirlpool is for some distance not more than 
one-half the average width, it is probable that through these 
spaces these small streams had worn in preglacial times 
narrow gorges leading to the Whirlpool which had only to be 
cleared of their glacial débris and somewhat enlarged by the 
present stream when the cataract had receded to that point. 
This would account both for the narrowness and the shallow- 
ness of the gorge at these places. Whereas the water at the 
Whirlpool is 150 feet deep and still more than that for two 
miles below the Falls, it is only 35 feet deep in the Whirlpool 
Rapids. Furthermore, at Fosters Flats, one mile below the 
Whirlpool there is a projecting shelf extending into the gorge 
from the western side nearly half its width, but into its upper 
end on the side next to the main cliff there is the head of an 
old narrow gorge opening up stream. This can hardly be 
anything else than a remnant of the gorge supposed to have 
been formed by a small northerly stream which found an 
outlet through the Whirlpool. 

We are bound to state, however, that Dr. Spencer main- 
tains that the St. Davids outlet was not worn down to the 
level of the present Whirlpool, and so is only a remnant of 
erosion in some preceding era. But it is to be observed that 
Dr. Spencer’s borings to determine the depth of the glacial 
filling in the St. Davids gorge, were considerably one side of 
the center, while the measurement nearest the. center was 
abandoned before penetrating the rock below. The great 
age of the gorge would imply a fully formed V-shape for it, 
which would make the depth of the glacial filling to be small 
near the sides. There is, therefore, no valid reason to doubt 
that the St. Davids preglacial outlet was complete from the 
Whirlpool at a depth equal to that of the present Niagara 
gorge. 

In view of all these considerations it seems evident that a 


TH#H DATE OF THE GLACIAL PERIOD. 551 


considerable portion of the erosion of the Niagara gorge, 
both above and below the Whirlpool, had been accomplished 
before the glacial period, so that all the present stream had to 
do was to clear of its unconsolidated till the portions of the 
preglacial gorge which it occupied, and somewhat widen the 
channel. 

For future reference, if for nothing else, it is worth while 
to introduce at this point a portion of our detailed study upon 
the rate at which lateral erosion is proceeding through 
atmospheric influences alone along the face of this gorge. 


In 


| 


Miaygara Ls. 


tagara SA. 


Sec 78 See TT 


Fie. 141—Sections showing the actuol rate of erosion along the sides of the Niagara 
Gorge. 


Section I was made 860 feet south of the tunnel at the north 
end of the gorge, and the measurements were taken from the 
outer rail of the track at points where a perpendicular excava- 


Say ee THE ICE AGE IN NORTH AMERICA. 


tion in the Clinton Shale had been made fifty-five years be- 
fore. The average of fifteen measurements.made at twenty 
foot intervals, showed that at the line of greatest erosion 
fourteen feet of the Clinton Shale had fallen away during 
that period; giving a rate of three inches a year. 

Section II was made 6.317 feet from the tunnel in what was 
a perpendicular excavation in the Niagara Shale fifty-five 
years before. The average amount of greatest erosion along 
this exposure was obtained by eleven measurements through- 
out a distance of 1.185 feet, and proved to be fourteen and 
eight tenths feet, or three and one quarter inches per year. 

From these measurements it appears that the rate at which 
the Clinton and Niagara shales crumble away-over the whole 
surface, through atmospheric agencies alone where unpro- — 
tected, is one and a half inches per year. 

The question as to how much protection has been afforded 
by the talus and the growth of vegetation cannot be defi- 
nitely answered, but as our photograph on p. 544 shows the 
Niagara shale has not been protected to any extent by a talus, 
and but slightly by vegetation. It therefore seems entirely 
within the bounds of probability that the erosion of the Nia- | 
gara Shale at the mouth of the gorge has proceeded at one- 
seventh the rate at the exposures measured, which is about 
one quarter of an inch per year, or one foot in forty-eight 
years, which is the rate necessary to accomplish the whole 
amount in 10,000 years. 


A second typical place for the study of the recession of 
post-glacial waterfalls is presented in the gorge of the 
Mississippi River below the Falls of St. Anthony at Min- 
neapolis. The problem here presented has been carefully 
studied by Professor N. H. Winchell as follows.* 


- From the Falls of St. Anthony to Fort Snelling the gorge 
between the rock-bluffs is somewhat less than a quarter of a 


* “Geology of Minnesota,’’ vol. ii, pp. 313-316, 340, 341. 


THE DATE.OF THE GLACIAL PERIOD. 503 


mile in width, and the rock has a freshly broken appearance, 
the large fragments thrown down by the action of the water 
on the easily crumbled sand-rock, as the falls have receded, 
still existing in the talus along the bluffs. Throughout this 
distance (about eight miles) the strata are horizontal, the thick- 
ness of the drift-sheet overlying them nearly uniform, and all 
other conditions, so far as they can be seen, that would affect 
the rate of recession, seem: to have exerted an unvarying in- 
fluence. The inference is inevitable that the rate of recession 
has been practically uniform between the two points named. 
There is an aspect of age, and long weathering, presented by 
the rock in the bluffs of the Mississippi below Fort Snelling. 
It has a deeply changed color, a light-yellow, oxidized exterior, 
which marks all old bluffs. The blue color is found at greater 
depths from the surface than it is in the rock of the bluffs 
above Fort Snelling. This stained condition also pervades the 
lime-rock at the mouth of Bassett’s Creek and at the quarries 
in the ancient river-bluffs near the mouth of Shingle Creek, 
on both sides of the river. Another notable difference between 
the bluffs above Fort Snelling and those below consists in the 
absence of caves, and subterranean streams entering the river, 
above Fort Snelling. Although the Trenton limestone exists 
in full force about St. Paul, in the bluffs east and north of the 
city, yet it had been cut through by some means prior to the 
drift so as to allow the entrance and exit of streams of water 
at levels below its horizon through the sandstone. None such 
are found above Fort Snelling. The surface drainage is shed 
by the limestone, and is precipitated over the brink of the 
gorge, forming several beautiful cascades. When such streams 
enter the river below Fort Snelling, they either enter some 
subterranean passage and appear at the mouths of caverns in 
the sandstone, or as springs in the drift along the talus, or 
they find an ancient ravine down which they plunge, by a se- 
ries of rapids over bowlders, to the river-level, rarely striking 
either the lime-rock or the underlying sand-rock. Again, the 
rock-bluffs at St. Paul, and everywhere below Fort Snelling, 
are buried under the drift-sheet. Their angles are sometimes 
seen jutting out from some wind-beaten corner, but nearly 
everywhere thev are smoothed over by a mantle of drift and 


oo4 THE ICE AGE IN NORTH. AMERICA. 


loam. Even the immediate river-bank, where the lime-rock 
should be intact, shows that it has been extensively disrupted 
and its débris, often coarse and water-worn, in pieces from four 
to ten feet long, is mixed with the coarse bowlders, gravel and 
the drift, at the height of fifty to seventy-five feet above the 
water-level, the heterogeneous mass lying on the worn upper 
surface of the St. Peter sandstone. But above Fort Snelling 
the upper edge of the lime-rock is intact all the way to the 
falls, and shows a fresh-cut section. It is surmounted by a 
continuous sheet of drift, which rises from the water-level in 
one bluff coincident with the rock-cut. Its individual strata 
show that they were cut by the recession of the falls in the 
same manner as the strata of the rock. They do not conform 
in their undulations to the outline of the rock, as if the gorge 
were present when they were formed, as at St. Paul. There 
is no spreading of loam over these cut edges, except such as 
has fallen down from above at the time of their removal or 
subsequent to it. At Fort Snelling, the direction of the Mis- 
sissipp1 changes abruptly at a right angle. The change is 
caused by entering the wide gorge which runs in that direc- 
tion. This gorge is that in which the Minnesota runs, and is 
out of proportion with the amount of water which it carries. 
This valley continues in the same direction, and with the same 
width, beyond the confluence of the Mississippi, but takes the 
name of the latter stream. At one mile below the mouth of 
the Minnesota it isa mile and a half wide. 

These features of greater age, pertaining to the bluffs of 
the Mississippi below Fort Snelling, are seen in the old rock- 
bluffs of the river above the mouth of Bassett’s Creek as far as 
to Shingle Creek. The rock there is deeply changed in color, 
and is hid by the drift, and the bluffs, as left by the more an- 
cient river, are far apart, the old gorge being three or four 
times as wide as that between the falls and Fort Snelling. 
These rock-bluffs, consisting of the same limestone as that 
which at the falls is below the water, here rise from thirty to 
forty feet above the river, and are buried under loam, or under 
drift and loam. This part of the old valley continues south-. 
wardly, by way of Bassett’s Creek (below its last turn), across 
the western suburbs of Minneapolis, through the valleys occu- 


THE DAT# OF THE GLACIAL PERIOD. 555 


pied by Lakes Calhoun and Harriet, and joins the Minnesota 
at some point above Fort Snelling, the precise locality being 


“FALLS IN 1830 
H\ FALLS IN 1680 


—s 

4 

%, 
4% 


= 
Zz 


if 


RY 


aut Re 


se ae 
a, 


— a 1 ty 


T 


= 
= 
A 
= 
S 
=— 
= 
~ 


LTS" 


Fie. 142_—Map of Mississippi River from Fort Snelling to Minneapolis and the vicinity, 
showing the extent of the recession of the Falls of St. Anthony since the great Ice 
age. Notice the greater breadth of the valley of the Minnesota River as described in 


the text. 
hid by a subsequent deposit of drift. It was cut down into 
the St. Peter sandstone over one hundred feet at least, as 
shown by the well at the Sumner school-house, and about two 


556 THE ICH AGE IN NORTH AMERICA. 


hundred and seventy-five feet, as shown by the deep well at the 
Lakewood Cemetery. ‘This would show that probably the an- 
cient valley of the Minnesota where it passes Fort Snelling, 
and all the way through Ramsey county and below, has been 
filled more than two hundred feet by drift that originated 
since the excavation of the gorge. ‘This supposition is borne 
out by all borings that have been made between the rock-bluffs 
at lower points, as at West St. Paul and at Lake City. Such 
excavation is not found in the river-gorge between Fort Snuel- 
ling and the Falls of St. Anthony ; but, below the water, are 
found, first, some large fragments of limestone, and some bowl- 
ders of foreign origin, the whole being generally less than 
twenty-five feet in thickness, and below that the undisturbed 
St. Peter sand-rock is found, suitable for the foundation of 
piers for bridges. 

These facts warrant the conclusion that that part of the 
Mississippi gorge above Fort Snelling has been excavated by 
the recession of the falls since the last general drift movement, 
and that prior to that event there was a gorge which passed 
from the present channel of the Mississippi at the mouth of 
Bassett’s Creek southward to the great gorge of the Minnesota 
at some place above Fort Snelling. It is probable that this 
gorge was then occupied by waters that drained from the 
northern part of the State, and had existed through many ages, 
dating back to pre-Cretaceous times. It seems to have been 
filled first by a blue till, or partly filled, and to have remained 
free for the passage of the Mississippi during the on-coming of 
the Glacial epoch, till the advent of the ice of the last Glacial 
epoch, when morainic accumulations so choked it that the 
water of the river was driven out and compelled to seek an- 
other passage to the Minnesota. When this last event took 
place, the Falls of St. Anthony probably began at Fort Snel- 
ling, the water being precipitated over the rock-bluff of the 
pre-existing old gorge, unless the whole valley was too deeply 
buried under water. Whether this was at the beginning or at 
the acme of cold, or at the recession of the ice, is a question 
which may well be considered, but at this time the only point 
that is claimed is that it was not earlier than the beginning of 
the last Glacial epoch, and was probably near the acme of cold. 


THE DATE OF THE GLACIAL PERIOD. 057 


Having thus established the post-glacial origin of the 
gorge below the Falls of St. Anthony, the next point was to 
determine the rate at which the recession has been proceed- 
ing. Fortunately, upon this point an abundance of evidence 
is available. The falls were first visited and described as 
early as 1680 by the Jesuit missionary Hennepin. His de- 
scription is found in the Amsterdam edition of his works, 
printed in 1704. The falls were again visited in 1766, eigh- 
ty-six years later, by Carver, another Jesuit missionary. In 
addition to his description this traveler made a sketch of the 
falls, which was engraved to accompany his travels, published 
in London in 1778. Subsequent travelers who describe it 
are Major Z. M. Pike, in 1805; Major Stephen S. Long, in 
1817; Schooleraft, in 1820; Professor William Keating and 
Mr. Beltrami, Rev. W. T. Boutwell and Schooleraft, in 1832; 
and Mr. G. W. Featherstonhaugh, in 1835. In addition vari- 
ous artists have gathered descriptions of the falls as they ap- 
peared in 1842, 1848, 1853, and in 1857, and daguerreotypes 
were taken in 1851; while in 1853, before the erection of saw- 
mills, Mr. J. W. Bond gave a careful description of the falls 
as they then existed, and numerous living witnesses fix their 
position in 1856, when artificial changes were introduced, 
which so modified the rate of recession as to disturb further 
calculation. The period, then, during which evidence is avail- 
able for caleulation is that between Hennepin’s visit in 1680 
and the year 1856—one hundred and seventy-six years. The 
descriptions are so minute that Professor Winchell is able to 
fix beyond doubt the various stages of recession between 
these dates. 

In 1680 the falls were near the south end of Hennepin 
and Spirit Islands, not far above the present Tenth Ave- 
nue Bridge. In 1766, at the time of Carver’s visit, the falls 
had receded about four hundred and twelve feet, and were at 
Carver’s Island. In 1856 the west falls were about tive hun- 
dred feet below their present position, which is now made sta- 
tionary by artificial means. According to Professor Winchell, 
the recession from 1680 to 1766, between Ilennepin and 


558 THE ICH AGE IN NORTH AMERICA. 


Carver, was four hundred and twelve feet ; and between 1766 
and 1856, six hundred feet, making a total between 1680 and 
1856, of one thousand and eighteen feet. ‘These give re- 
spectively the rates 4°79, 6°73, and 5:08 feet per year, and for 
the corresponding periods necessary for the recession of the 
falls from Fort Snelling (a distance of a trifle over eight 
miles) 8,819 years, 6,276 years, and 8,315 years. The aver- 
age of these three results is 7,803 years.” 

Professor Winchell then proceeds to discuss the possible 
elements of error in this calculation : 

1. That arising from difference in the volume of the 
river. The terraces already described in the chapter on 
“ Preglacial Drainage,” as characterizing both the Minnesota 
River and the upper Mississippi, reveal the existence of 
_ enormous floods during the closing stages of the Glacial pe- 
riod. Indeed, these floods in the Minnesota River were so 
high as to fill it up to the level of the lime-rock at Fort Snel- 
ling, about one hundred feet. During the existence of this 
high water, therefore, there could have been no cataract at 
Fort Snelling or farther up the Mississippi. The Falls of 
St. Anthony could have begun only after the floods of the 
Minnesota began to shrink so as to uncover the lime-rock at 
Fort Snelling. 

2. Difference in the height of the falls at various points 
from Fort Snelling up to its present position. Thisis shown 
to be comparatively insignificant, so that it can be left out of 
the account. 

3. The stage of the Glacial period when the recession 
began. Upon this we quote again at length : 


This point has already been considered in the possible va- 
riations in the volume of the river. It is probable that the 
Mississippi, in diminutive form, began to flow in its new 
channel at the acme of the cold,* since the moraine of the sec- 
ond Glacial epoch runs across the country, approximately 
through this region, and since it would have remained in its 


* See map of Minnesota in next chapter (Fig 181). 


THE DATE OF THE GLACIAL PERIOD. 599 


preglacial channel till it was driven out by the encroaching 
moraine. It was the easier removed from its old channel by 
reason of its reduction in volume. When it began its course 
in its new channel, it flowed over a broad plain of gravel and 
sand, the then latest accumulations of glacial torrents. This 
plain of gravel and sand extended throughout the adjoining 
space now occupied by such drift deposits. The same kind of 
deposits filled the whole Minnesota Valley, from side to side, 
and rose as high as the plains back of Fort Snelling. The 
river, being comparatively small, had but little effect on these 
deposits. If it excavated any channel, the torrents from the 
ever-present glacier-ice filled them at once—indeed, 2 exca- 
vated, i¢ refilled, as 7¢ was glacier-born.. It was on the retire- 
ment of ice, bringing a greater drainage area into contribution 
to swell the main streams at this latitude, that these rivers 
began to deposit the fine loam-sand which covers the coarse 
gravel and sand of these terraces. It was still later, when 
the rivers were shrunk, by the partial or complete with- 
drawal of the glaciers from their remote sources, that they 
began to excavate through the loam and the gravel and 
sand and finally entered on the slow erosion of rock-gorges. 
Thus it appears that the date from which the recession of 
the falls must be reckoned was after the outlet of Lake 
Agassiz had been opened toward the north, one of the last 
acts of the Ice age. .. . 

Finally, if all the supposed irregularities be allowed their 
full force, and all the elements of doubt be admitted, their 
combined effect would not, at the most, more than slightly 
modify the result. And even if it should double the first result, 
or should reduce it to one half, the chief value of the calcula- 
tion is not impaired. That consists in showing the lateness of 
the last Glacial epoch compared with the enormous time that 
has sometimes been supposed to have elapsed since its de- 
parture. 

If the occurrence of our winter in aphelion, caused by the 
precession of the equinoxes and the revolution of the line of 
the apsides, about eleven thousand three hundred years ago, 
was the cause of our last Glacial period, it follows that it re- 
quired about thirty-five hundred years for the withdrawal 


560 THE ICH AGE IN NORTH AMERICA. 


of the ice-margin from the vicinity of Fort Snelling to that 
place where the discharge of Lake Agassiz was operied to- 


ward the north, reducing the Minnesota to nearly its present 


size. This change must have given prominence and erosive 
effect to the waterfall at Fort Snelling, if it did not give it 
birth. 


These calculations concerning the age of Niagara and 
the Falls of St. Anthony are amply sustained by the study 
of various minor waterfalls and gorges in Ohio to which I 
have myself given special attention. For example, at Elyria, 
twenty-five miles west of Cleveland, Black River plunges 
over the outcropping Waverly sandstone, and flows onward 
to the lake through a wide valley in the Erie shale, which 
was doubtless preglacial, though no buried channel above 
has yet been discovered. The gorge below the falls, which 
has been eroded since glacial times, and which approximately 
represents the work done by Black River during that time, 
is only a trifle over two thousand feet long. The water 
flowing over the falls represents the drainage of about four 
hundred square miles, and the sandstone which forms the 
precipice over which the water plunges is underlaid by soft 
shale very favorable to rapid erosion. In March, 1871, a 
mass of rock fell which was so large that the concussion 
shook the whole town and produced the semblance of an 
earthquake. With the present forces in operation at this 
point, it would seem incredible that the average rate of re- 
cession should not be considerably more than one foot in 
fifty years. Yet thus infinitesimal would be the rate if one 
hundred thousand years must be allowed for the time separat- 
ing us from the birth of the present waterfall at Elyria. 
The shortness of this and other similar gorges in that region 
points to a great reduction of the prevalent estimates of 
glacial chronology. 

Another interesting confirmation of this moderate esti- 
mate is to be found in Paint Creek Valley, in the southern 
part of Ohio, to which attention was directed in a previous 
chapter. As was discovered by Professor Orton several years 


_— — 


THE DATE OF THE GLACIAL PERIOD. 561 


ago, this stream, a few miles above its junction with the 
Scioto, at Chillicothe, abandoned its preglacial valley in a 
most singular manner.* The preglacial valley of Paint 
Creek for about twenty miles above its junction with the 
Scioto runs in a northeast direction from the town of Bain- 
bridge. The valley is nearly a mile wide at the bottom, and 
about five hundred feet below the general level. But the pres- 
ent stream, after it has abandoned this old valley, occupies 
for two or three miles a narrow gorge not over five hundred 
feet wide, cutting directly through the table-land, and re- 
entering the old valley considerably lower down in its course. 
The only satisfactory explanation of this is found in a study 
of the local glacial phenomena. The lower or northeastern 
part of this preglacial valley is exactly on the line of the gla- 
cial boundary, and was for a certain period obstructed by the 
most advanced portions of the glacier, which dammed up 
the water and raised it to a level at which it would be forced 
in front of the ice across a tongue of the table-land, thus 
eroding the present channel.+ 

This portion of the channel, as already indicated, is about 
three miies long, from three hundred to five hundred 
feet deep, five hundred feet wide at the top, and two hun- 
dred at the bottom. The walls near the top consist of fifty 
or sixty feet of Waverly sandstone, while all below is a soft 
shale crumbling very readily. The question in glacial chro- 
nology is to find the age of this gorge, which is clearly post- 
glacial. The true solution of the problem comes from a 
study of one of the lateral gorges formed by a small tributary 
entering the main gorge midway from the south. This 
tributary, though dry a portion of the year, is at other times 
a raging torrent, and drains an area of two or three square 
miles. Yet in the soft shale, so favorable for rapid erosion, 
it has worn a gorge less than six hundred feet long, but hav- 
ing a mouth of nearly the same width where it joins the 


* “ Geological Survey of Ohio,” vol. ii, p. 653. 
+ See map, p. 373. 


562 THE ICE AGE IN NORTH AMERICA. 


main channel. It can scarcely be possible that these forces 
have been in operation in their present position for many 
thousand years; for, ac- 


cording to the testin.uny 


of Mr. Long, who has 
been a resident upon the 
ground for fifty years, 
and has definite data for 
calculation, this tributary 
creek has worn back sev- 
eral feet since his re- 
membrance. If the rate 
of recession for this trib- 
utary gorge were as little 
as one foot in twenty 
years, only twelve thou- 
sand years would be re- 


plishment of the work 
Fig. 143.—ldeal view of an old unglaciated coun- 
try, showing the form assumed by the emi- done. If we should go 


nences when erosion has proceeded to a great ° 
extent. (United States Geological Survey.) back to the period as- 


any be signed by Mr. Croll’s the- 
ory to find the Glacial period, the rate of recession would 
be incredibly slow, and far below what is pretty certainly the 
rate at the present time. 

An extreme length was at one time given to the intergla- 
cial episodes by attributing to interglacial time much erosion 
that was preglacial. For example Professor Chamberlin in 
his early publications regarded the gorge of the Ohio and the 
Allegheny as well as those of the Delaware and the Lehigh as 
the work of interglacial erosion. If this were the case, the 
interglacial episodes must have been of enormous extent, for 
these are rock gorges ot great length and 200 or 300 feet in 
depth. 

Subsequent investigations, however, showed that the most 
of this erosion was preglacial rather than interglacial. At 
Warren, Pennsylvania, on the Allegheny River, as already 


* 


quired for the accom- . 


edn snk, 


aa = 


~~ 2g ede 


i ai 


THE DATE OF THE GLACIAL PERIOD. 563 


detailed, the upper gravel terraces which Professor Chamber- 
lin had separated from the lower ones by this enormous 
interval, were found to 
be continuous, showing 
that they belonged to 
the same period, while 
deeply buried gorges filled 
with glacial débris of 
Kansan age opened into 
the main channel from 
the south. As already 
remarked, also, the high- 
level terraces of the 
Monongahela were not, 
as Professor Chamberlin 
maintained, ordinary 
river flood-plains, but 


eZ 77 = Z = sae oak 
shore lines of a glacial Fie. 144—A country, in contrast with that on the 


opposite page, in which the drainage has been 
lake produced by dam- disturbed by glacial deposits and the streams are 


ming upo Se eoutlel this beginning to wear new channels. (Chamberlin.) 
Lake Erie, by way of the Mahoning and Grand River valleys. 
The most, therefore, that can be made of the interglacial 
time from the erosion of the Ohio River gorge is that needed 
for the wearing down of the cols between the branches of the 
various streams that were flowing north and were dammed up 
by the advancing ice-sheet. As already shown it was the 
junction of these upper branches which formed the present 
tortuous channel of the Ohio River. The gorge of the Dela- 
ware was proven to be preglacial by the investigations of 
Professor E. H. Williams, which brought to light the fact that 
at Bethlehem, Pa., the present Lehigh River flows over a 
bed of glacial débris filing an old channel which is 120 feet 
deep, and this in a region reached only by the very earliest 
ice invasion. The rock gorge of the Delaware into which the 
Lehigh empties must, therefore, be wholly preglacial. 


564 THE ICE AGE IN NORTH AMERICA. 


Another most instructive illustration of the extent of 
preglacial erosion is found west of Keokuk, Iowa,* where there 
isa buried channel of great width now filled with glacial débris 
while the river at Keokuk flows over a rock bottom and 
through a comparatively narrow channel. 


' 
| 
ty 
1 
ral 
a 
re) 
“J 
\ 
| 
| 
! 
| 
! 
' 
| 


S 
2 


CCAR = ae 


Fic. 146—Cross section of the new course of Plum Creek, showing its original width and 
its enlargement in twelve years. 


Another means of measuring thhe amount of erosion 
since the Glacial period is found in post-glacial river-valleys 


by estimating the amount of material which has been car- 


ried out by the present streams from the glacial deposit 
itself. 

Professor Hicks, of Granville, Ohio, reported in 1884,7 
some important results of such an investigation in the valley 
of Raccoon Creek, Licking county, near the glacial border. 
Thi present flood plain of this creek is now bordered on 
either side by gravel terraces about fifty feet high, which are 


*See cut on page 310. 
+ ‘Baptist Quarterly’’ for July, 1884. See also Fig. 99, p. 324. 


awed 


THE DATE OF THE GLACIAL PERIOD. 565 


evidently the remains of a modified glacial deposit formerly 
filling the whole valley to that height. Since the Glacial 
period the present stream has been occupied with the task of 
slowly removing this material. The number of cubie yards 
which it has already carried away can be approximately esti- 
mated. The rate of removal is more difficult to determine. 
Assuming the rate to be the same per cubic foot of water as 
that which is transported by the Mississippi River past New 
Orleans, which doubtless is far too small, the time required 
would be, according to the calculation of Professor Hicks, 
less than fifteen thousand years. 

I have been able to make a more definite calculation in 
connection with Plum Creek, in Oberlin, Ohio. The situa- 
tion is peculiarly favorable both on account of its relation to 
the glacial shore lines around Lake Erie, and of its freedom 
from disturbing obstacles. The section of the Creek Valley 
from which the facts are gathered lies ten miles south of the 
present shore of Lake Erie, and 250 feet above the lake level. 
It is about five miles south of the highest of the lake ridges, 
and fifty feet higher than the upper ridge. Its course is 
_ wholly in glacial till with no rock bottom anywhere in its 
course. The average gradient of the stream is twelve feet 
to the mile, falling 100 feet in eight miles. It is evident that 
the stream did not begin the erosion of its present trough 
until the ice-sheet had retreated from the water-shed on the 
south and had uncovered the outlet of the glacial lake at 
Fort Wayne, which determined the level of water on whose 
shores the upper ridge was thrown up by the waves. The 
Plum Creek trough is therefore older than the Niagara gorge 
by the length of time that was required for the retreat of the 
ice-sheet from the south shore of Lake Erietothe Adirondack 
Mountains, a distance of 200 or 300 miles; for, asalready said, 
Niagara did not begin its work until the Mohawk Valley, 
south of the Adirondack Mountains was free from ice. 

Now, in 1895, a reservoir was constructed in the village 
occupying the whole width of the trough of the creek, and 


566 THE ICE AGE IN NORTH AMERICA. 


compelling the engineers to open a new channel across an 
undisturbed neck of the original glacial till. The section of 
this chosen for observation was 500 feet long, and at first 
consisted of a ditch twenty-one feet wide at the top, and 
ten at the bottom, with an average depth of eleven feet, 
though on the south side it rose to a height of twenty feet 
above the bottom. But, after a lapse of twelve years (in 
1907), the stream had enlarged the ditch to a width of fifty- 
one feet at the top, andof seventeen feet at the bottom, giving 
an average width of thirty-four feet compared with the original 
of fifteen and one-half feet. A simple mathematical calcula- 
tion shows, therefore, that in twelve years this stream had 
removed from a 500-foot section whose banks were exposed 
to the direct action of the current on both sides, 101,750 
cubic feet of solid matter, or, 8,450 cubic feet per annum. 

To get a more perfect basis of comparison, measurements 
were taken of a section 5,000 feet long below the village, where 
the original conditions had been undisturbed. In this sec- 
tion the eroded trough averaged 400 feet in width and seven- 
teen feet in depth, and this entirely in glacial till such as 
characterizes the whole valley. The total amount, therefore, 
of work accomplished, by the stream in this section since the 
present line of drainage was opened was the removal of 
34,000,000 cubic feet of till. 

To obtain a still more approximate basis for calculation 
it was necessary to measure the length of the sections of the 
edge of the trough whcre the stream impinges directly against 
the bluff and so is eroding under conditions similar to those 
in the cut-off at the reservoir. Upon doing this it was 
found that these exposed sections amounted to 1,600 feet in 
length, which is 600 feet more than that of both sides of the 
cut-off. The annual erosion, therefore, in the 5,000-foot 
section is now one and six-tenths greater than in the cut-off, 
making 13,568 cubic feet of material per year. At this rate 
the 34,000,000 feet of material from the 5,000-foot section 


THE DATE QF THE GLACIAL PERIOD. 567 


would be removed in 2,505 years; a result so incredible that 
we are called to examine more closely into the various con- 
ditions affecting the problem, some of which would tend to 
retard the eroding action of the stream, and some to accel- 
erate it. 

Of the retarding influences the most conspicuous is the 
former existence of a dense forest of large trees covering the 
whole basin. It is scarcely possible, however, that the rate 
would be reduced from this cause lower than to one-tenth of 
that of the present time, which, if there were no counteract- 
ing causes, would extend the time to 25,000 years. 

But, on the other hand, it is evident that the rate of erosion 
in the main trough is, at its present width, at a minimum. 
For, as the width of the trough has enlarged, it has taken the 
stream a longer and longer time to swing from side to side in 
its meanderings. At the outset the stream acted through the 
entire length on both sides as it now does in the cut-off, and 
when the width of the trough was half what it is now, the 
erosion was twice as fast. 

It is safe to say, therefore, that the average rate during 
the forested condition would be twice what we have allowed. 
This would reduce the time to 12,500 years, which cannot be 
far from a correct estimate. For, in addition to the early 
constriction of the channel in increasing the rate, it should 
be kept in mind that on the first withdrawal of the ice there 
was no forest to retard the action of the stream. Further- 
more, it is altogether probable that there was a much greater 
precipitation over the basin of the creek while the ice lingered 
over the area immediately to the northward, and this would 
increase the rate of erosion. 

It has been necessary to enter thus fully into details con- 
cerning one instance in order to get the force of the cumula- 
tive argument from the innumerable similar instances which 
present themselves all over the area in which the natural 
drainage is towards the front of the ice-sheet. Present 


568 THE ICE AGE IN NORTH AMERICA. 


eroding forces cannot have been at work over this region for 
much more than 10,000 years, and this is some time previous 
to the beginning of the work of the present Niagara River. 


Another class of facts which seems to set moderate limits 
to glacial chronology relates to the amount of superficial ero- 
sion of glacial deposits of various sorts, and the extent to 
which the rocks have been disintegrated since that period. 

President T. C. Chamberlin, when State geologist of 
Wisconsin, remarked that no sensible denudation had taken 
place there since glacial times.* Even Mr. Croll expresses 
surprise at the small amount of erosion which has taken 
place since the kames of Scotland were deposited. Both in 
Europe and in America these peculiar relics of the Glacial 
period retain a sharpness of outline which it is difficult to be- 
lieve could have survived the protracted period of one hun- 
dred thousand or even of forty thousand years, according to 
Hitchcock’s reckoning. When, also, one considers the chemi- 
cal agencies at work to decompose the rocks wherever un- 
protected by a covering of till, the freshness of the glaciated 
surfaces never ceases to be a cause of astonishment. 


Dr. Geo. F. Becker, of the United States Geological Sur- 
vey, bears striking testimony to the freshness of the glaciated 
surfaces of the rocks in the mountains of California on the 
Pacific Coast. He writes: 


“No one, who has examined the glaciated regions of ‘the 
Sierra can doubt that the great mass of the ice disappeared 
at a very recent period. The immense areas of polished 
surfaces fully exposed to the severe climate of say from 
7,000 to 12,000 feet altitude, the insensible erosion of streams 
running over glaciated rocks, and the freshness of erratic 
bowlders are sufficient evidence of this. There is also evi- 
dence that -the glaciation began at no very distant geologic 
date. As Professor Whitney pointed out, glaciation is the 
last important geological phenomenon and succeeded the 
great lava flows. 


* “Geology of Wisconsin,”’ vol. ii, p. 632. 


THE DATE OF THE GLACIAL PERIOD. 569 


“There is also much evidence thai erosion has been trifling 
since the commencement of glaciation, excepting under 
peculiar circumstances, east of the range, for example, at 
Virginia City; and sites which there is every reason to sup- 
pose preglacial have scarcely suffered at all from erosion, 
so that depressions down which water runs at every shower 
are not yet marked with water-courses, while older rocks, 
even of tertiary age and close by, are deeply carved. The 
rainfall at Virginia City is, to be sure, only about ten inches, 
so that rock would erode only say one-third as fast as on the 
California coast; but even when full allowance is made for 
this difference, it is clear that these andesites must be much 
younger than the commencement of glaciation in the north- 
eastern portion of the continent as usually estimated. So, 
too, the andesites near Clear Lake, in California, though 
beyond a doubt preglacial, have suffered little erosion, and 
one of the masses, Mount Konocti (or Uncle Sam), has 
nearly as characteristic a volcanic form as Mount Vesuvius.’’* 


Dr. Bell} alsowrites as follows: “On Portland promontory, 
on the east coast of Hudson’s Bay, in latitude 58°, and south- 
ward, the high, rocky hills are completely glaciated and bare. 
The strie are as fresh looking as if the ice had left them 
only yesterday. When the sun bursts upon these hills 
after they have been wet by the rain, they glitter and shine 
like the tinned roofs of the city of Montreal.” Again, Pro- 
fessor Macount writes of the red Laurentian gneiss in the 
vicinity of Fort Chippewayan, at the west end of Lake Atha- 
basca: “The rocks around the fort are all smoothed and 
polished by ice action. When the sun shines they glisten 
like so much glass, and a person walking upon them is in 
constant danger of falling.” 


* “Bulletin of the Geological Society of America,”’ vol. ii, pp. 
196, 197. To the same effect see the testimony of Prof. I. C. Russell 
and Prof. Gilbert, below p. 609. 

t “Bulletin of the Geological Society of America,’’ vol. i, p. 308. 

t ““Geological Survey of Canada, Report of Progress,’’ 1875-1876, 
p. 90. 


570 THE ICE AGE IN NORTH AMERICA. 


“Likewise, concerning the glaciation of Europe, we find 
that in Wales and in Yorkshire, England, the amount of 
denudation of limestone rocks on which bowlders lie has 
been regarded by Mr. Mackintosh* as a proof that a period 
of not more than six thousand years has elapsed since the 
bowlders were left in their positions. The vertical extent 
of this denudation, averaging about six inches, is nearly the 
same with that observed in the southwest part of the Province 
of Quebec by Sir William Logan and Dr. Robert Bell, where 
veins of quartz marked with glacial striae stand out at 
various heights not exceeding one foot above the weathered 
surface of the enclosing limestone. 

As illustrating how little we know about the causes which 
produce the variations in snow fall, even from year to year, 
and render it impossible to form trustworthy a priori opinions 
concerning the proximity of the causes which are capable of 
producing glacial conditions, Mr. Becker writes that in 
1890 the “snowfall in the Sierra was exceptionally large, 
about two and one-fourth times the average precipitation — 
having fallen. Much of this snow remained unmelted through 
the season, and when I left the mountains, on October 1, 
there were still thousands of snowbanks where in ordinary 
seasons none remains even far earlier in the season. Many 
of these banks were also of great depths, say 100 feet, more 
or less. It is clear, therefore, that were this and succeeding 
winters to be as wet as the last, the range would show glaciers 
in great numbers, much as the Alps now do; in short, the 
glacial period of the Sierra would recur in a moderate way. 
Now, no one doubts that there was some cause for the unusual 
snowfall of 1889-90 but no one has any suspicion what it 
was. No sensible change in cosmical or terrestrial condi- 
tions has occurred, the weather of the world at large was not 
remarkable, and, excepting as to precipitation, the year was 
not extraordinary even in California.” 


* “Quarterly Journal of the Geological Society,’’ vol. xxxix, pp. 
67-69; vol. xlii, pp. 527-539. 


THE DATE OF THE GLACIAL PERIOD. 571 


Again evidence comes from the extent to which lakes, 
dating from the Glacial period, have been filled with sedi- 
ment. Little reflection is required to make it evident that 
our present lake-basins could not always have existed; for, 
except where counteracting agencies are at work, the “ wash” 
of the hills will, in due time, fill to the brim all inclosed 
areas of depression. Mr. Upham, of the Minnesota Geo- 
logical Survey, expresses surprise at the small extent to 
which the numerous lakes of that State have been filled 
with the sediment continually washing into them. “The 
lapse of time since the Ice age has been insufficient for rains 
and streams to fill these basins with sediment, or to cut out- 
lets low enough to drain them, though in many instances we 
can see such changes slowly going forward.” * 

Dr. E. Andrews, of Chicago, has made calculations, de- 
serving of more attention than they have had, concerning the 
rate at which the waters of Lake Michigan are eating into 
the shores, and washing the sediment into deeper water or 
toward the southern end of the lake.t The United States 
Coast Survey have carefully sounded the lake in all its parts, 
and have ascertained the width of the area of shallow water 
extending inward from the shores. It is well known that 
waves are limited in their downward action, so that there 
will be a surrounding shelf, or shoulder of shallow water, in 
cases where the waves of a deep lake are eroding its banks. 
This fringe of shallow water encircling Lake Michigan is 
only a few miles wide; and from such data as have been gath- 
ered, the average rate of erosion is found to be as much as 
five or six feet per annum; which would indicate that the 
lake-basins had not been in existence more than seventy-five 
hundred years. 

Leaving these more indefinite and in many respects un- 
satisfactory efforts to estimate the age of lake-basins, we 
may get some assistance in approximating to a correct chro- 


* “ Minnesota Geological Report” for 1879, p. 73. 
+ “American Journal of Science,” vol. xeviii, 1869, pp. 172 et seg. 


572 THE ICE AGE IN NORTH AMERICA. 


nology of the Glacial age by studying the smaller kettle-holes | 
which constitute so marked a feature in the kames and 
moraines of the glaciated region. As already shown, the most 
satisfactory explanation of these curious depressions is, that 
they mark places where masses of ice were buried in the 
débris of sand and gravel brought down by the streams of 
the decaying glacier ; and where, upon the melting of the 
buried ice, a cone-shaped depression was left with sides as 
steeply inclined as the nature of the soil would permit. At 
any rate, there can be no question that the kettle-holes were 
formed during the closing stages of the Glacial period. 

As typical of numberless others we present the facts 
concerning a kettle-hole near Pomp’s Pond in Andover, 
Mass.* 


Pomp’s Pond is itself a moraine basin about a quarter of a 
ile in diameter, and but slightly above the level of the Shaw- 
shin River, into which it empties. Upon its north side is an 
accumulation of gravel and sand, with pebbles intermingled, 
in which there are several of the smaller characteristic bowl- 
shaped depressions of which we have spoken. Their appear- 
ance is much like that of volcanic craters. You ascend a 
sharp acclivity from every side toarim of gravel, and then 
descend as rapidly into the bowl-shaped or crater-like depres- 
sion.. A section carried across will present the idea. 


Ve. 147,— Section of kettle-hole near Pomp’s Pond. Andover, Massachusetts. (See sie 
(For general view of the situation, see Fig. 101, p. 338). 


From the level of the pond, and two or three rods from the 
edge, you begin to ascend at an average rate of about one foot 
in three, till the south side of the rim is reached, at a height 
of fifty-two and five tenths feet above the pond. (a) (This rim 
is not, however, of a uniform height. On the east side it rises 


* T here transfer a few paragraphs from my “Studies in Science and Re- 
ligion.”’ 


i i 
~ 


THE DATE OF THE GLACIAL PHRIOD, 573 


into a pyramid seventy-seven feet high.) (0) Then, descending 
fifty and five tenths feet vertically, you are carried one hundred 
and thirty-eight feet horizontally, reaching at that point the 
edge of a circular mass of peat which is ninety-six feet in di- 
ameter. (c) From the opposite side the ascent of the northern 
rim begins, and you descend from its top to the valley, repeat- 
ing almost exactly the first descent from the pond. The dis- 
tance from rim to rim, or the diameter is three hundred and 
eighty feet. 3 

It is evident that since the first formation of this crater- 
shaped depression no material can have reached the bottom, 
except from three sources: 1. The wash from the side ; 2. 
The decay of vegetation which grew within the circumference 
of the rim; 3. The material brought by the winds. It is 
equally evident that what is once in can not get out. 

Dust, leaves, and twigs carried by the winds inevitably 
lodge in such depressions more thickly than in other places, 
since the atmosphere in such hollows is comparatively quiet. 
For the same reason the surrounding trees as they are blown 
down are more likely to fall toward the center of the kettle- 
hole ; and the ashy material which their roots abstract from 
the sides of the depression is no insignificant factor in the 
problem. 

Now, from the angle of the declivity, the original depth of 
the depression can be approximately estimated. If the angle 
be still the same as at first, the first three terms of the propor- 
tion would be 138 : 50°5 :: 48 : 1743, making the original 
depth below the present surface of the peat a trifle over 17°5 
feet. If, however, we suppose the original slant to have been 
steeper and the rim higher, we can still see that there must 
have been a limit to the depth. Suppose the rim to have been 
one third higher and the slant one third steeper, we then 
should have in round numbers the proportion 138 : 68 :: 48: 
2345, making the original depth of the depression nearly 
twenty-four feet below the present surface of the peat. From 
the nature of the material it is impossible that the depth could 
originally have much exceeded that amount. 

Accepting this conclusion, the problem is, to determine the 


time it would require the agencies mentioned above to fill the 


o¢4 THE IGE AGE IN NORTH AMERICA. 


bottom of this bowl to a depth of twenty-four feet—a cone 
ninety-six feet in diameter at the base and twenty-four feet to 
the apex—which would be equal to a deposit of only eight feet 
over the present surface of the bottom. ‘The question is, 
Could this have stood with so little change for eighty thousand 
years ; or even for forty thousand years, if we were to accept 
Professor Charles H. Hitchcock’s estimate of the prolongation 
of the effects of Croll’s period ?* Is not the supposition of 
ten thousand years sufficiently extravagant ? If the close of 
the great Glacial period be so far back as Mr. Croll estimates, 
we must believe that sediment would accumulate, in the situ- 
ation above described, over the surface of the present peat-bog, 
at the rate of only one inch in a thousand years; while, if 
we put the close of this period back ten thousand years, the 
rate of accumulation would seem to be as slow as our imagina- 
tion can well comprehend. One hundred inches, which is 
little more than eight feet, divided into one hundred thousand 
parts, would be only :001 of an inch; that is, if this depression 
has been in existence one hundred thousand years, we must 
believe that with all the dust there is in the air, and all the 
soil that would wash down the steep incline of all the sides, 
and all the vegetable matter growing in and falling into the 
depression, one thousand years would be required for one inch 
of sediment to accumulate! If we reduce this supposed period 
to 50,000, 25,000, and 12,500 years successively, the time re- 
quired for the accumulation of an inch of sediment would be 
proportionally 500, 250, and 125 years. If any one will be 
at the trouble of dividing an inch into 125 equal parts, he will 
probably be surprised at the insignificance of the quantity. 
The slowest rate at which Boucher de Perthes calculates for 
the accumulation of peat over Roman pottery in the valley of 
the Somme is three centimetres, or a little over an inch, in a 
century. 

We do not bring railing accusation against those who, from 
astronomical considerations, confidently speak of the close of 
the Glacial period as an event which occurred scores of thou- 
sands of years ago; but it is important to know what other 


* “Geology of New Hampshire,” vol. iii, p. 327. 


., = 


THE DATE OF THE GLACIAL PERIOD. 57 


Or 


beliefs that long chronology carries with it. If any one 
chooses to believe that kettle-holes can stand one hundred 
thousand years, and fill up only twenty-four feet from the 
apex of the inverted cone, he must run the risk of bene 
considered credulous. 


Inrejectingthe theory of Mr. Croll concerning an indefinite 
succession of glacial periods, we did not mean to foreclose 
the discussion connecting the question whether there have 
not been several Pleistocene glacial epochs. This question 
must, therefore, now be considered with more particular 
reference to its bearing upon matters of chronology. As 
the reader doubtless observed in the remarks upon Croll’s 
theory, quoted from Mr. Gilbert and President Chamber- 
lin, in the preceding chapter, each of them spoke of an ‘‘In- 
terglacial Period’ as clearly indicated in North American 
geology. The calculations just made relate to the chronology 
of what President Chamberlin called the “second glacial 
epoch.” Niagara Falls, the Falls of St. Anthony, the kettle- 
holes of Massachusetts, and the valley of Plum Creek, 
are none of them upon the extreme border of the glaciated 
region. Raccoon Creek is nearer the margin. Calculations 
respecting those interior points, therefore, do not give the 
date of the extreme marginal deposits. Hence it becomes 
a matter of prime importance to consider to what extent 
the ice retreated during the various climatic episodes 
which characterized the epoch. Many, perhaps most, of 
the authorities on glacial subjects at the present time ho!d 
that during two or three of these episodes the ice retreated 
as far as the Laurentian Highlands and then re-advanced to 
the limits of what are called respectively, the Iowan, the 
Ilinoisan and the Wisconsin boundaries of glacial drift. 
It is necessary, therefore, to discuss these questions in con- 
siderable detail. 

The most obvious evidence adduced in favor of inter- 
glacial epochs in America consists of the so-called ‘inter- 


076 THE ICE AGE IN NORTH AMERICA, 


glacial” forest-beds.* These forest-beds and vegetal de- 
posits occur over a wide area, and in places have glacial de- 
posits both under them and over them. The first supposi- 
tion with regard to them was that these various forest-beds 
were contemporaneous, and indicated a general retreat of - 
the ice after its first invasion of North America until it had 
entirely disappeared or lingered only in the Canadian high- 
lands; whereupon there was a readvance of the ice, over- 
whelming the forests and other vegetal deposits which had 
collected in kettle-holes and other depressions, and burying 
them beneath a second sheet of ground-moraine, where they. 
are opened to present inspection whenever wells penetrate 
them or eroding streams expose them on their banks. But 
it is not clear that these interglacial forest-beds might not 
originate in front of the margin of the slowly retreating ice 
if only there were comparatively brief periods of readvance 
along successive lines of latitude. Thus they may belong to 
various times of oscillation, both during the general advance 
and during the general retreat of the glacier. If, for ex- 
ample, at any time during the period of advance there had 
been a retrocession of the ice-front for a short distance, for- 
ests and vegetable growth would soon have spread over the 
marginal belt from which the ice had retreated, and, upon 
a readvance, these would be overwhelmed and covered with 
a new stratum of glacial deposition. In case of some of 
the peat-beds, it is probably necessary to suppose that they 
were formed where they are, and are really interglacial ; but, 
in case of many of the fragments and logs of wood found 
in the glacial deposit, we are not compelled to suppose an 
interglacial origin. Wood will stand transportation in the 
ground-moraine almost as well as bowlders, and it is by no 
means certain that much of the timber found in the till may 


* See Chamberlin, “ Geology of Wisconsin,” vol. i, chap. xv, especially 
pp. 271-291; “ Driftless Area,” pp. 211-216; N. H. Winchell in “‘ Proceedings 
of the American Association for the Advancement of Science,” vol. xxiv, 1875, 
pp. B, 438-56; “Geology of Minnesota,’ vol. i of the ‘‘ Final Report,” pp. 363 
et seqg.; J.S. Newberry, “ Geological Survey of Ohio,” vol. ii, pp. 30-33. 


Fic. 148.—Perpendicular section of till at Oxford, Ohio, showing a piece of wood three 
inches in diameter projecting from the face. This has evidently been transported in 
the till like a bowlder. The section is about fifty feet ; portion shown, about fifteen 
feet, near the middle. (United States Geological Survey.) (Wright.) 


578 THE ICE AGE IN NORTH AMERICA. 


not have belonged to the original forests which covered the 
country in front of the first sheet of advancing ice. These 
logs may have been picked up like the bowlders, and trans- 
ferred to the south a long time after their original deposi- 
tion. Thus, it may be that the “forest-beds” near the mar- 
gin of the glaciated area are of more recent origin than those 
some distance back, since the ice in its final retreat may 
have proceeded with few and slight oscillations. As Presi- 
dent Chamberlin suggests, also, “ certain subaqueous deposits 
so closely resembled true till that they have been mistaken 
for it, and there is perhaps no case of superposition of beds 
supposed to represent two glacial periods that is not still 
open to these doubts.” * 

President Chamberlin, whose knowledge of the facts 
bearing on this subject is wider than that of any one else, 
therefore does not rely so much upon the existence of in- 
closed forest-beds and a supposed superposition of distinet 
beds of glacial débrzs, in proof of distinct glacial epochs, as 
upon certain other considerations of a more general nature, 
such as the following : 


The earlier drift is characterized, in the interior basin, 
by a wide but relatively uniform distribution, manifesting 
only occasional and feeble tendencies to aggregation in mo- 
rainic ridges. It is not bordered, except in rare instances, by 
a definite terminal moraine, but ends in an attenuated border. 
It is not characterized by the prevalence of prominent drum- 
lins or other similarly ridged aggregations. The phenomena of 
glacial erosion connected with it are generally feeble. Glacial 
striz are indeed present, even in the peripheral portions, but 
the surface of the rock is not usually extensively planed. The 
whole aspect of the deposit indicates an agency which spread 
the drift over the surface smoothly, and relatively gently, with 
little forceful action. The drainage phenomena are also of 
the gentle order. We have yet failed to find evidence of very 
vigorous drainage connected with the older drift of the in- 


* See “Geology of Wisconsin,” vol. i, p. 272. 


THE DATE OF THE GLACIAL PERIOD. 579 


terior basin except in osars and kames, whose conditions of 
formation were exceptional, but, on the contrary, abundant 
proof of slow-moving waters and imperfect drainage, indicat- 
ing low slope of the surface. | 

The later Glacial epoch, on the contrary, was character- 
ized by strong glacial action, planing the rock-surface vigor- 
ously, even up to the very limit of its advance. The glaciers 
plowed up immense moraines about their edges, except on 
smooth plains whose slope was away from the ice-movement. 
The drainage was usually vigorous, and immense trains of glacial 
gravel stretch away from the margin of the ice-sheet, reaching 
great distances down the valleys and frequently filling them 
to great depths with well-assorted material. The vigorous 
action of the glaciers of the second epoch and the rapid drain- 
age, in general, stand in marked contrast with the gentle 
action and imperfect drainage of the earlier epoch. One of 
the conditions that determined the distinction was probably 
the difference in elevation that characterized the two epochs. 

The interval between these two leading epochs we regard as 
the chief interglacial epoch, representing a greater lapse of 
time and a greater change in the dynamic agencies of the age 
than the several other interglacial intervals, or episodes of 
deglaciation, which mark the complicated history of the Ice age. 

As belonging to the earlier Glacial epoch, we recognize two 
drift-sheets that have been described by the geologists of the re- 
spective States as occurring in southwestern Ohio, southern In- 
diana, central and southern Illinois, eastern and southern Iowa, 
northern Missouri, eastern Nebraska; and southeastern Min- 
nesota. 

Between these occur, at numerous points, vegetal and fer- 
ruginous accumulations and other evidences of a non-glacial 
interval. To this horizon belong the larger number of de- 
posits described under the term ‘‘ old forest-bed,” but very 
many vegetal deposits so referred do not, in our judgment, 
belong there, but are referable to several distinct horizons. * 


Others adduce as evidence of the distinct Glacial epochs 
in North America the greater oxidization and general de- 


* “ Driftless Area,” pp. 214, 215. 


080 THE ICE AGE IN NORTH AMERICA. 


composition of the material upon the extreme border of the 
glaciated region as compared with that of the kettle-moraine 
in Wisconsin, and what is considered to be a moraine of corre- 
sponding age in the regions both east and west. 


A striking evidence of the reality of this difference in 
oxidization is related by Professor Penck. When Mr. Frank 
Leverett was visiting him in Germany the two went out 
together into the Alpine fields where Professor Penck had 
distinguished three well marked stages of glaciation of — 
increasing amounts of oxidization and erosion. These suc- 
cessive periods of glacial and interglacial episodes he had 
named after three streams in the foothills of the Alps in south- 
ern Germany, where the deposits are typically present; 
viz., Mindel, Riss and Wiirm.* In every instance Mr. Leverett 
was able to correlate these with the three divisions which he 
had made in America; viz., the Kansan, corresponding to 
the Mindel period; the Illinoisan to the Riss; and the Wiscon- 
sin to the Wiirm. But he did not recognize the Iowan. All 
these identifications were made in the field without previous 

knowledge of Professor Penck’s determinations. But with 
~ reference to this evidence it is to be noted: 

1. That the more complete oxidization of the glacial 
débris along the southern border and the greater decomposi- 
tion of the granitic bowlders and pebbles distributed over this 
border, are naturally accounted for by the obvious fact that 
for the most part the material along the southern border, 
and for some distance back from it, was that which was first 
picked up by the advancing ice, and was probably already 
oxidized and partially decomposed by the long-continued 
action of preglacial agencies when the ice began its removal. 
Its oxidization, therefore, may not be any true indication of 
the remoteness of its transportation and deposition. It is 
evident that every successive period of movement from the 
north would operate upon lower strata of rock and upon the 
masses which had been less affected by secular agencies of 


*See above page 459. 


THE DATE OF THE GLACIAL PERIOD. 581 


decomposition. Thus it is natural that the more northern 
moraines and glacial deposits, of various kinds, a = 
fresher than the southern. fen’: : 


The peculiar facts brought to light concerning the oxidiza- 
tion of the belt of oldest till, bordering the Wisconsin moraine, 
in Pennsylvania, are worthy of close attention in this connec- 
sion. As already noted, Professor Williams found by exten- 
tive field work that the moraine as marked by Lewis and 
Wright across Pennsylvania was not the extreme boundary of 
glacial action, but lay on an average twenty or twenty-five 
miles back from that boundary. This attenuated border was 
teferred to by Lewis'and Wright as “the fringe,” but they 
did not endeavor to ascertain its limit in that state: ‘The 
deposits over that area would, however, now be correlated 
without doubt with those of Kansan age in the ‘Mississippi 
Valley. 

It is noteworthy, therefore, that the surface outcrops 
over this attenuated belt (examined inthousandsof places and 
at all elevationsineastern Pennsylvania up to 650 feet ‘above 
tide, and under caps of glacial deposits only a few feet thick, 
that vary from loose gravels to compact clays) are universally 
fresh and undecomposed, showing that the already oxidized 
deposit was laid upon a freshly glaciated surface, and that 
time enough has not since elapsed to decompose or oxidize 
the gneiss, limestone, and slate rocks to any appreciable 
extent. A striking illustration of this has already been given 
in connection with the mammoth coal-beds at Morea, Pa., 
within one mile of the extreme limit of glaciation, and twenty- 
five miles south of the moraine of Lewis and Wright (p. 154). 
Here the surface of the rock is distinctly glaciated, and 
covered with from six to ten feet of sandy till through which 
water easily percolates. But the coal is rotted only to the 
depth of three-fifths of one inch, while immediately south of 
it, in the unglaciated region, it is rotted to the depth of many 
feet. 


582 THE ICE AGE IN NORTH AMERICA. 


2. The till over this attenuated border is a mixture of 
fresh and oxidized material at all levels, showing that most 
of the oxidization preceded the glaciation, and that not suffi- 
cient time has elapsed since for the oxidization of the fresh 
material picked up by the glacier. This statement is based 
upon the examination of sections miles in length; when it 
everywhere appears that there is such a mixture of fresh 
material with oxidized material that the conclusion is irre- 
sistible that it was one movement which brought both. 

For example, in the vicinity of Warren and south of Oil 
City at an elevation of 380 feet above the Allegheny River 
numerous pebbles were found, both of sedimentary and of 
granitic rocks, which had evidently been oxidized nearly to 
their center before starting on their journey from Canada, 
but had been planed down on one side so as almost to expose 
the core on that side, while leaving the oxidized layers undis- 
turbed on the other. Some of these described were five inches 
or more in diameter and had been rotted so that only an 
inch or more of fresh nucleus remained; while in some cases 
the unoxidized core was exposed through the glacial erosion 
of one side. These instances were numerous. Mr. Williams 
informs me that ‘‘one striking peculiarity in those with joint 
planes through which the water could readily reach the 
center, was that the relative permeability of the mass from 
its different sides did not have the slightest influence on the 
position of the fresh nucleus. It was as often nearer the side 
whence water could most easily enter than to any other side. 
This impressed me greatly,” he says, “‘asan indication of the 
extreme recency of the final shaping as with time the relative 
porosity of the various sides would tend to bring the re- 
maining nucleus under the usual law as to position.” 

I am permitted, also, to use the following extract from 
Professor William’s unpublished notes, in which he sums up 
some most significant facts concerning the Kansan advance: 


“The glaciated outcrops in the east [in Pennsylvania] are 


THE DATE OF THE GLACIAL PERIOD. 583 


solid: those in the west more oxidized and rotten, but the 
critical condition in the west. as in eastern Pennsylvania 
is the constant presence and mixture of fresh rolled material. 
As the age of the mixture is the age of the freshest part, 
there is finally no difference between the ages of the eastern 
and western Kansan drift. 

“The rustiness of the western gravelsshows that they were 
the rolled and weathered surface fragments picked up by 
the ice, and modified by its action. With the crystallines 
which are thoroughly oxidized to their center, we find a 
few specimens which look on one side like a piece of rusty 
gravel. The black bisilicates have entirely disappeared, 
and have left pits and a rusty staining. The feldspar also 
has kaolinized. In these very old ones, the glaciated sides 
were never scraped down to the fresh interior, but uniformly 
show a rusty though solid exterior, quite smooth and firm 
to the hammer. 

“By breaking these, we would find that the solid nucleus 
might be one-eighth of an inch from one side which had been 
glaciated, and three inches or more from the other side which 
had remained unglaciated.” 

I am not aware that adequate attention has been paid to 
this class of facts over the Iilinoisan and Kansan areas in the 
Mississippi Valley, but I was much impressed with the fresh- 
ness of the Canadian bowlders which were found at Tus- 
cumbia, on the Osage River, in central Missouri, and by the 
freshness of many of the pebbles in a great gravel-pit at Hol- 
liday on the Kansas River a few miles above Kansas City to 
which the railroads have resorted for a long time for ballast 
and which contains much material from the far north. 

In this connection it is proper to call special attention to 
the accumulating evidence going to show that the glacial 
movement from the Keewatin center was not strictly con- 
temporaneous with that from the Labradorian center but 
preceded it by a longer or shorter interval. 

In the first edition it was suggested that the remarkable 
re-entrant angle in the glacial border at Salamanca, N. Y., 
indicated the junction of two ice-movements from widely 


584 THE ICE AGE IN NORTH AMERICA. 


separated centers of accumulation to the northeast and north- 
west. Positive evidence in support of this was found, as 
already stated, by Prof. Williams in 1897 in the discovery of 
a rolled piece of native copper from Lake Superior firmly 
imbedded in till at East Warren, Pa., forty feet below the 
surface, showing that the older ice-movement from the north- 
west invaded the region now coverd with the later deposits 
from the northeast to the extent of several hundred miles; 
for, as already shown, northeastern drift extended some dis- 
tance across the Mississippi at Burlington, Iowa. 


The most important evidence supposed to indicate the 
complete retirement of the continental ice-sheet between 
successive deposits is found near Toronto, Canada. This was 
first investigated by Dr. G. J. Hinde in 1878, but has since 
been more thoroughly studied by Professor A. P. Coleman, of 
Toronto University. Briefly stated the facts are that in the 
valley of the Don River and at Scarboro Heights near Toronto 
there is at the base a deposit of till which after having been 
extensively eroded was covered by sedimentary deposits 150 
feet in thickness which had been brought into standing water 
by the stream to form a delta whose base extended twenty-five 
or thirty miles along the shore. The lower strata of this delta 
deposit are thirty-five feet below the present level of the lake, 
and probably at about the same relative level as when laid 
down. But the water from some unknown cause rose as the 
accumulation progressed until it was 150 feet higher than 
now, when the upper sediments of coarser gravel were depos- 
ited the water began to fall, and a period of erosion succeeded. 


This proceeded until at Scarboro a V-shaped channel, 
one mile wide at the top and 150 feet deep, was worn in the 
sedimentary deposits, whereupon the ice advanced again 
and covered the whole with sheets of bowlder clay and 
assorted drift to a total depth of 200 feet. Here certainly 
seems to be an interglacial deposit of unusual extent. 

Nor is the character of the fossil plants and animals 
included. in the interglacial deposits any less noteworthy. 


THE DATE OF THE GLACIAL PERIOD. 585 - 


Both the fauna and the flora of the lower, or Don, beds indi- 
cate a much warmer climate than those of the upper, or Scar-: 
boro beds. In the Don beds there are found leaves and wood 
of maple, elm, ash, hickory, basswood, and even of pawpaw 
and osage orange which now flourish only in latitudes several 
degrees south of Toronto. Also, of the mollusks found in the 
Don beds, four of the species are not now found in the St. 
Lawrence basin, but only after passing the watershed which 
separates it from that of the Mississippi. 

On the other hand, the upper, or Scarboro sands and 
clays are wanting in the species indicating a warmer climate 
but abound in both a flora and a fauna suggestive of Labra- 
dor and of the region north of Lake Superior. 

In the opinion of Professor Coleman these facts cannot, 
be accounted for except on the supposition that the earlier 
ice-sheet retired from practically the whole region to the 
northward before the latter one began its advance; which 
certainly looks very reasonable at first sight. But there are 
a number of considerations, too much overlooked, which 
perhaps permit a contrary conclusion. 

1. Weare not warranted in assuming that the advance of 
the ice was simultaneous from the Keewatin and the Labra- 
dorian centres. On the contrary it seems certain, as has been 
shown above, that the advance from the Keewatin center 
was much earlier than from the other. The so-called Kansan 
till underlies the Illinoisan for several hundred miles east of 
the Illinoisan border. For example the Illinoisan ice crossed 
the Mississippi at Burlington, Iowa, and advanced many 
miles westward. But Kansan ice had at an earlier time 
spread eastward so as to carry Lake Superior copper as far 
as Warren in Western Pennsylvania. In a previous chapter 
(p. 527) attention is called to the fact that the boundary of 
the glaciated areas in the central and eastern parts of the: 
United States consists of the arcs of two circles with their 
centers respectively in Labrador and the Lake Superior region. | 
This will appear at a glance by consulting the map. Now, 


586 THE ICE AGE IN NORTH AMERICA. 


the junction of these arcs is at Salamanca, New York, almost 
exactly on the meridian of Toronto. It is therefore a plau- 
sible hypothesis that the lower till at Toronto was deposited 
by the Keewatin ice-sheet near its eastern margin and that 
it withdrew some time before the Labradorian sheet reached 
that point. | 

This opens up a wide field of speculation connected with 
our theories of the cause of the spread of the various ice-sheets. 
On the theory that elevation of land is the prime cause it 
would appear that the rise of land proceeded in a wave from 
west to east. The Keewatin center therefore rose first and 
sent out its ice-sheets far south to Kansas,and east to Pennsyl- 
vania. Then as it began to sink under its accumulating load 
of ice, the eastern or Labradorian center began to rise and in 
due time started its glaciers to meet the vanishing ones from 
the Keewatin center. But, possibly long before Toronto was 
reached by the Labradorian ice-sheet, the Keewatin glacier had 
retired from its eastern limit amid conditions of climate that 
were essentially preglacial. For it must be borne in mind that 
the retreat of the ice can only take place when the climate is 
abnormally warm. Indeed such warmth would seem to be 
essential for the melting of the ice. 

An interesting direct.proof of this was found by Dr. Holst 
in southern Sweden, where he excavated gravel beds in front 
of the principal moraine which contained remains of plants 
and animals characteristic both of warm and cold climates 
in close connection, and which must have been contemporane- 
ous. Similar facts were reported to me by Professor Tscher- 
naschev from Finland. Itis also well known that large species 
of oysters lived long after the glacial epoch in Maine, especially 
at Damariscotta, which do not survive except on our southern 
coasts. It isin point also to instance the spread of the masto- 
don, the mammoth, the rhinoceros and even the hippopot- 
amus under the conditions which prevailed in northern 
Europe and Asia during the glacial period. 


THE DATE OF THE GLACIAL PERIOD. 587 


A further line of inferences follows from studying the 
probable cause of the rise of the water in Lake Ontario dur- 
ing the accumulation of the interglacial delta at Scarboro. 
This, as we have stated, was 150 feet, and the deposits at the 
bottom indicate a warm climate, and those at the top a cold 
climate. Now if we study the conditions involved it will 
appear that there isstrong confirmation of the theory just 
advanced. Evidently, as Professor Coleman points out, 
the deposition of the Don beds began when the level of Lake 
Ontario was just about what it is at the present time. That 
would imply that its outlet was still through the St. Lawrence, 
which must then have been unobstructed by ice. But as the 
Labradorian ice advanced and closed up this outlet the water 
level would eventually rise to the height of the col at Rome, 
N. Y., leading through the Mohawk into the Hudson River. 
This is 200 feet above Lake Ontario. But as it is shown that 
now the axis of post-glacial elevation is the Mohawk Valley, 
the north shore of Lake Ontario may well have been rela- 
tively fifty feet higher during glacial times than it is now, 
which would bring the elevation of the col at Rome into exact 
harmony with that of the upper Scarboro beds. Under this 
theory we have that gradual passage from warm to colder 
conditions which we need to account for the change in species 
in passing from the lower to the upper beds. And this is 
just what Dr. Lamplugh has shown to be the case in the 
glacial deposits of England.* 

2. The uniformity in the distribution of the till over the 
southern portion of the glaciated area in the Mississippi 
Valley is partly an illusion, due to the fact that the great 
amount of loess covering the region, especially in southern 
Indiana and Illinois and in eastern Nebraska, prevents, to a 
considerable extent, observations upon the original surface, 
and this loess, as has already been shown, is doubtless the 


* “Presidential Address to the Geological Section of the British 
Association for the Advancement of Science,’’ at York, 1906. 


588. THE ICE AGE IN NORTH AMERICA. 


finer part of the glacial débris carried southward by the gla- 
cial streams—so that, upon any theory, we should expect a 
much larger accumulation of loess over the southern portion 
of: the area. | 
| Mr. Leverettrelieslargely on the great erosion of the Kansas 
sheet tillasanindicationofitsage. He estimates, for example, 
that innorthern Missouri not over thirty per cent of the origi- 
nal plainisleft upon the retreat of the ice, in the narrow tabu- 
lar remnant remaining upon the divides. ‘‘The streams are 
flowing in valleys that have broad slopes and bottoms, the 
slopes being so toned down as to fall generally below 5° and 
not uncommonly to 3° or even less. Theslopes of the valley, 
twenty-five meters in depth, often havea breadth of about a 
kilometer, and the bottoms of small drainage lines often 
exceed a kilometer in width. Topographic sheets of the 
United States Survey, which well illustrate the post-Kansan. 
erosion, are the Atlanta, Edina, and Kahoka quadrangles of 
northern, Missouri.” (See comparison of North American 
Glacial; Deposits, from “ Zeitschrift fur Gletscherkunde,”’ vol. 
iv, p., 298). 
~ With this he compares a part of the Belleville, Ill., topo- 
graphic sheet which shows 60 per cent or more of the original 
glacial plain untouched by erosion; but again in the Iowan 
drift. (which Mr. Leverett would now identify with the Illi- 
noisan epoch), the portion of the glacial plain which is undis- 
sected is not greatly in excess of the Kansan plain from 
Missouri. 

It should benoted furthermore that the blanket of Kanga 
till is comparatively uniform over its whole area. There are 
no moraines in it, and there never were any. Moreover, the 
deposit was rarely thick enough to disguise the preglacial 
topography. Much of the supposed evidence of post-glacial 
erosion. is probably the result of this: failure of the glacial 
cee vy iD fill the valleys Siar channels of ae original topog- 
raphy. | 


eCr Rats 


1:83333. 


' aoe 


re = = 


Be ale§ or 1.666660. eae se 


sheet. Scale #; Million or 
erosion. 
n drift. 


foto 
as art re : 
» 2. 3.9 
oe Be de 
a e al: 
ee } 
Sa HE re ge 
=n SME - 


: NY ae eo. 
eras BRN iy eee 


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in 


(Ko ey VSS on Gre ae P| 


PALE ee if bos 


a ees + 


Fic. 149—Part of Altanta 
_ Co tourinterva]l 20 feet 


590 THE ICE AGE IN NORTH AMERICA. 


The controlling influence of the preglacial topography may 
be observed in the neighborhood of Galesburg, Illinois, where 
all along the divide between the Illinois and Mississippi 
rivers the surface presents an extensive general level, covered 
with glacial drift of Illinoisan age to a considerable depth. 
But as one proceeds on either side towards the rivers men- 
tioned the size of the preglacial valleys increases so rapidly 
that the glacial blanket is not sufficient to disguise them, 
while near the water-shed on both sides appear the original 
extensive amphitheaters characteristic of valleys of extreme 
age. , 

Evidently the post-glacial erosion is not by any means so 
great as would at first appear to be the case. But what seem ~ 
to be valleys of post-glacial erosion are simply adjustments of 
the glacial blanket to the precedent valleys of erosion. 

Again, the broad valleys bordering the south-flowing 
streams of gentle gradient in the Illinoisan and Kansan 
regions differ only in moderate degree from similar valleys 
in the Wisconsin area. As instances I would note the valleys 
of the Nishnabotna, the Tarkio, the Nodaway, and the 
Platte rivers of northwestern Missouri, all of which rise in 
southwestern Iowa, and, after flowing long distances, enter 
Missouri. One can but be impressed in crossing these valleys 
with their great width, and with the signs that they were 
occupied by immensely larger streams of water than it is 
possible to provide under present conditions. On comparing 
these valleys with that of the river Styx, a small streamin 
Wisconsin drift just south of the water-shed in MedinaCounty, 
Ohio, we find a very small stream occupying a level flat- 
bottomed valley, a third of a mile wide, which is evidently 
the product of the lingering ice and the floods pouring through 
the valley during the melting of the late Wisconsin period. 
The contrast between this valley and the valleys in north- 
western Missouri is by no means great, certainly not so great 
as to imply an enormous lapse of time between their formation. 


THE DATE OF THE GLACIAL PERIOD. o91 


In both cases, doubtless, the wide troughs were preserved 
by the presence of lingering masses of the melting ice sheet. 

3. The theory of a general depression of the glaciated 
area with reference to the sea-level may apply to a certain 
portion of a single period as well as to one of two distinct 
periods. We may suppose a low slope of a surface and the 
consequent imperfect drainage and slow-moving waters dur- 
ing the maximum extent of a single glacial epoch as well 
as during the first of two epochs. The theory that the 
weight and attraction of the ice were tangible factors in pro- 
ducing the relative depression of land which characterized a 
portion of the Ice age would lead us to expect the greatest 
depression during the period of maximum extension. When 
the ice-front had retreated from Carbondale, Ill., to Mad- 
ison, Wis., the intervening area had been relieved from an 
enormous amount of pressure. 

4. With reference to the comparative absence of glacial 
strize and of planing and grooving over the southern area, it 
should be noted, first, that fresh exposures of rock in that 
region are very infrequent, owing to the great depth of till 
and loess; and, secondly, that upon any theory the gla- 
cial grooving and striation would necessarily grow fainter as 
the boundary was approached, because the movement of ice 
over that portion was so much less than over the central and 
northern portions; and, thirdly, the absence of planation 
is not relatively so great as is sometimes represented. The 
grooves and striz in Highland and Butler counties, Ohio, 
very near the margin, and in southwestern Indiana and 
southern Illinois, still nearer the margin, are as clear and 
distinct as can anywhere be found. Also, upon the surface 
of the limestone rocks, within the limits of the city of St. 
Louis, where the glacial covering was thin, and disintegrat- 
ing agencies had had special opportunities to work, I found 
very clear evidences of a powerful ice-movement; and at 
Du Quoin, IIl., only forty or fifty miles back from the ex- 
treme limit of glaciation, I was greatly impressed with the 
extent to which the surface rock had been planed, by ex- 


592 THE ICE AGE IN NORTH AMERICA. 


amining the fragments brought up from a shaft which had 
recently been sunk first through fifty or sixty feet of surface 
soil, and then for some distance into the rock. The small 
fragments from the surface of the rock thrown up were 
most beautifully planed and striated. 

A thorough study of the condition and disteibatea of 
the buried forest-beds bears strongly, as I can not but think, 
against the complete separation of glacial epochs in North 
America. In addition to the facts about to be enumerated, 
it is a significant circumstance that the buried vegetable de- 
posits under consideration do not mark a warm climate, but. 
a climate much colder than the present—such a vegetation, 
in fact, as would naturally flourish near the ice-margin. The 
buried forests of southern Ohio have a striking resemblance 
to those we described in Glacier Bay, Alaska. Peat and 
hardy coniferous trees are predominant. 

One of the most instructive localities in which to sindy 
organic remains embodied in glacial deposits is in the region, 
included in the southern part of Montgomery and the north- 
ern part of Butler county, Ohio. The glacial deposits con- 
taining organic remains in that. vicinity were first described 
by Professor Orton, of the Ohio Survey, in 1870.* Near 
Germantown, on Twin Creek, in Montgomery county, about 
thirty miles north of Cincinnati, there is exposed, at a sharp 
angle of the stream, a perpendicular bank of drift ninety-five 
feet in height. Underneath this is a deposit of peat as much 
as fourteen feet thick. The upper portion of the peat “ con- 
tains much undecomposed sphagnous mosses, grasses, and 
sedges.” . Both the stratum of peat and the clayey till above 
‘contain many fragments of coniferous wood, some of 
which ean be. identified as red cedar (Juniperus Virginia- 
nus).” Immediately above the peat-bed there is from tifteen 
to twenty-five feet of what seems to be true till. This shows 
no sign of stratification, and abounds in striated stones. 
Next above occurs a band about ten feet thick of stratified 


* “ American Journal of Science,” vol. ¢, 1870. 


THE DATE OF THE GLACIAL PERIOD. 593 


material containing coarse gravel and a good deal of fine 
sand. Above this to the top seems again to be true till, 


Fie. 151.—Section of till near Germantown, Ohio, overlying thick bed of peat. The man 
in the picture stands upon a shelf of peat from which the till has been eroded by the 
stream. The dark spot at the right hand of the picture, just above the water, is an 
exposure of the peat. The thickness of the till is ninety-five feet. The partial strat- 
ification spoken of in the text can be seen about the middle of the picture. The fur- 
rows up and down had been made by recent rains. (United States Geological Sur- 
vey.) (Wright.) 


with, however, an occasional pocket of sand or thin stratum 
of stratified material. But, both up and down the stream 
from this point the till merges into gravel-beds partially ce- 


594 THE ICH AGH IN NORTH AMERICA. 


mented together by infiltrations of lime and iron. Down 
the stream the stratum of peat rises to a higher level, so as 
eventually to come in contact with the first band of stratified 
material just mentioned, the intervening till gradually thin- 
ning out between them. The appearance is that of a saucer- 
shaped deposit of peat such as would have formed in a ket- 
tle-hole, and which was subsequently filled and covered with 
the advance of the glacier. 

That the facts indicate a somewhat prolonged interval 
between the first advance of the ice over the immediate re- 
gion and the second, can not, therefore, well be denied, for 
the peat is clearly enough between two glacial deposits. But 
it may well be questioned whether an interval of two or three 
centuries would not suffice for the accumulation of the peat 
described ; for it will be observed that it seems to have oc- 
curred in a large kettle-hole in which the vegetable matter 
naturally gravitated toward the center and is much deeper 
there than near the edges. It is not therefore allowable 
to take the extreme thickness of peat as the measure of the 
amount of accumulation during the interglacial period. | 

As to the rapidity with which peat may accumulate in 
favorable circumstances, we can do no better than transfer 
a recent discussion of the subject from the pen of the veteran 
botanist, Leo Lesquereux, contributed to the “ Annual Report 
of the Pennsylvania Geological Survey for 1885 ” : * 


Two conditions are necessary for the origin and growth 
of peat—water either stagnant in basins, lakes, pools, etc., or 
water abundantly supplied by a boggy atmosphere, increased 
by dense forest-growth. 

Pools of stagnant water, when not exposed to periodical 
drying up, are invaded by a peculiar vegetation : first, mostly 
composed of conferve, simple, thread-like plants, of various 
color and of prodigious activity of growth, mixed with a mass 
of infusoria, animalcules, and microscopic plants, which, partly 
decomposed, partly continuing the floating vegetation, soon 


* Pages 106, 107, 113, 114. 


THE DATE OF THE GLACIAL PERIOD. 995 


fill the basins, and cover the bottom with a floating of clay- 
like mold. So rapid is the work of these minute beings, that 
in some cases from six to ten inches of this mud is deposited 
in one year. Some artificial basins in the large ornamental 
parks of Europe have to be cleaned of such muddy deposits of 
floating plants, mixed with small shells, every three or four 
years. 

When left undisturbed this mud becomes gradually thick 
and solid—in some cases of great thickness, affording a kind 
of soil for the growth of marsh-plants, which root at the bot- 
tom of the basins or swamps and send up their stems and 
leaves to the surface of the water or above it, where their 
substance becomes in the sunshine hard and woody. 

As these plants periodically decay, their remains, of course, 
drop to the bottom of the water; and each year the process is 
repeated, with a more or less marked variation in the species of 
the plants. After a time the basins become filled by these suc- 
cessive accumulations of years or even centuries, and then the 
top surface of the decayed matter, being exposed to atmos- 
pheric action, is transformed into humus and is gradually cov- 
ered by other kinds of plants, making meadows and forests. 

In this way many deposits of peat are buried under- 
ground and remain unknown until discovered by diggings or 
borings. Such are the immense peat deposits in the great 
swamps of Virginia, the Dismal Swamps, and all along the 
shores of the Atlantic from Norfolk to New Orleans. 

In other cases when basins of stagnant water are too 
deep for the vegetation of aquatic plants, Nature attains the 
. same result by a different special process, namely, by the pro- 
longed vegetation of certain kinds of floating mosses, espe- 
cially the species known as sphagna. These floating masses 
grow with prodigious speed, and, expanding their branches in 
every direction over the surface of ponds or small lakes, soon 
cover itentirely. They thus form a thin floating carpet, which, 
as it gradually increases in thickness, serves as a solid soil 
for another kind of vegetation, that of the rushes, the sedges, 
and some kinds of grasses, which grow abundantly mixed with 
the mosses, which by their water-absorbing structure furnish a 
persistent humidity sufficient for the preservation of their re- 


596 THE ICE AGE IN NORTH AMERICA. 


mains against aérial decay. The floating carpet of moss be- 
comes still more solid, and is then overspread by many species 
of larger swamp-plants and small arborescent shrubs, espe- 
cially those of the heath family ; and so, in the lapse of years 
by the continual vegetation of the mosses, which is never inter- 
rupted, and by the yearly deposits of plant remains, the carpet 
at last becomes strong enough to support trees, and is changed 
into a floating forest, until, becoming too heavy, it either breaks 
and sinks suddenly to the bottom of the basin, or is slowly 
and gradually lowered into it and covered with water. .. . 

The absorbing power of the peat-mosses enables them to 
grow higher and higher above their original water-level, from 
which they thus gradually emerge. The name emerged bogs 
has been therefore given them. 

The peat of emerged bogs is less compact; the annual 
layers are more distinct, generally well defined in their succes- 
sion. At the top of the bog the layers measure about one inch 
in thickness, at the bottom less than one eighth inch, and 
in old bogs still less. The growth, therefore, though not very 
rapid, is easily observed and registered in several ways. 

It may be measured by compass and level from the border 
of the swamp, the central portion of which becomes gradually 
higher and higher, screening from the view of a spectator on 
one side of it objects which had been before observable on the 
other side of it. 

It may be estimated also by a time-scale, in cases where 
ancient bridges, pavements, etc., whose epoch of construction 
is certified by documents, are ee buried under beds of 
peat of known thickness. 

Again, in places where peat-bogs have been worked for a 
number of years, old pits are encountered, now entirely re- 
filled ; and when this happens with peat, during the life of 
the proprietor, who has himself dug the old pits and can recall 
the exact date, very precise data are thus furnished for learning 
the amount of time necessary for the reproduction of a bk 
thickness of peat. 

The rate of growth depends, of course, on atmospheric or 
other local circumstances, but, putting together many such 
pieces of documentary testimony obtained in different coun- 


THE DATE OF THE GLACIAL PERIOD. 597 


tries, the average production of compact matter may in a 
general way be estimated at one foot in a century. 

In immerged bogs, formed of vegetable débris falling into 
water, the peat grows more slowly and less regularly. The 
actual rate of its growth has not yet been positively recorded. 
In very extensive bogs, stretching between Swiss lakes, timber 
posts have been discovered on the line of an old road, and 
parts of a bridge buried beneath five or six feet of compact, 
black peat. Although the exact date of these constructions 
has not been fixed, the discovery of Roman medals in the 
vicinity suggests the beginning of the Christian era. ‘This 
shows that the kind of peat which results from the maceration 
of plants under water is of much slower growth than the peat 
layers of the emerged boys. It is also more compact, and is 
quite black, the vegetable matter being more completely de- 
composed, and its internal structure generally so destroyed as 
to be unrecognizable. The peat of emerged bogs, on the con- 
trary, is yellowish-brown, fibrous, its annual layers distinct, 
and the woody fragments more generally recognizable. 


Since the above was written a well sunk at Germantown 
through the till 100 feet deep, nearly a mile northeast of the 
exposure shown on p. 593, penetrated a peat layer several 
feet in thickness, showing that the deposit is extensive and 
perhaps older than we had estimated. It should also be said 
that Mr. Leverett is not fully convinced thatthe gravel under- 
neath the peat is glacial, but thinks that it probably is. 

But we are not compelled to assume a slow growth, nor 
even the average growth asthe rate. The cool, moist climate of 
a glacial age would seem to be peculiarly favorable to both 
the growth and the preservation of peat; so that two hun- 
dred or three hundred years is perhaps ample for the pro- 
duction of all the facts connected with the peat accumula- 
tions at this point. If it be asked how such a deposit of 
peat could be overwhelmed with ice without disturbance, the 
answer is that, as suggested by N. H. Winchell, before che 
reinvasion of ice the peat in the kettle-hole and probably the 


598 THE ICVh AGE IN NORTH AMERICA. 


rim of the whole had become frozen, and so capable of re 
taining its form. 

Similar deposits of peat in superficial kettle-holes are very 
frequent in the glaciated region, and constitute an important 
portion of. the reserved stores of fuel laid up for the future 
use of man. Professor Lewis and myself had an excellent 
opportunity to study such a modern deposit at Freehold, 
Warren county, Pa.* Here one half of such a hole had 


=== Sir trattif ew of yeh 7 


——— SS 
- SSS 


Fic. 152—Section of kettle-hole in Freehold, Pennsylvania. (See text.) 


been removed in making a road, and exposed a complete 
and fresh section through the middle. The depth of the 
peat in the middle was six feet, growing gradually thin- 
ner in each direction toward the sides. Peat and soil were 
mingled in alternate layers near the edges. Numerous logs 
of prostrate trees were also imbedded in the peat. It is 
evident that had there been a readvance of the ice over this 
region after the above accumulation was complete, and had 
the soil become frozen, there would have been at Freehold 
an interglacial deposit of vegetable matter closely analogous 
to that described at Germantown. 

A comparatively short interval between the periods of 
recession and advance of the ice-front in southern Ohio is 
also indicated in numerous places where fragments of wood 
are found imbedded in true glacial deposits near the glacial 
margin. For example, near Darrtown, on Four-Mile Creek, 
in Butler county, Ohio, is an exposure of till, sixty-five feet 
high, containing fresh red-cedar logs near the bottom, and 
fragments of wood in all conceivable positions throughout 
the lower half of the deposit. The deposit is true till, being 


unstratified and full of scratched stones, many of which are - 


granitic. There is, however a line of stratified material 


* See “Second Geological Survey of Pennsylvania, Z,” p. 171. 


a 


THE DATE OF THE GLACIAL PERIOD. 599 


about half-way up the bank, which is about two feet thick, 
and contains pebbles several inches in diameter. Not much 


Fig. 153.—Section in till near Darrtown, Butler County, Ohio, sixty-five feet high. 
Coarse line of stratification near the middle. Fresh cedar logs at the bottom. (See 
text.) (United States Geological Survey.) (Wright.) 


wood is found above this line, yet there is some, and the 
structure above seems identical with that below. All this 
would seem to indicate that there was a temporary retreat of 


600 ‘THE ICH AGE IN NORTH AMERICA. 


the ice, when fora short time water sorted and deposited 


material over the lower stratum of till; then there was a re- 
advance, pushing along a vast mass of unsorted material over 
the stratified stratum without disturbing it. In the deposit 
already described near Germantown, evidence of as many as 
four such marks of successive advances and retreats can be 
seen. 

Again, near Oxford, in Butler county, a few miles up 
the same stream (Four-Mile Creek) from Darrtown isan ex- 
posure of till where the unstratified character is perfectly 
manifest in which I observed and photographed a piece of 
wood, well preserved, projecting from the perpendicular face 
of the bank about forty feet below the surface, and where no 
land-slide could have occurred.* _ Equally good sections were 
also seen on Aunt Ann’s Run, near the city of Hamilton, in 
the same county, and only about twenty miles north of Cin- 
cinnati. 

Usually, as has been remarked, these buried deposits of 
peat and wood have been assumed to imply the existence of 
two distinct glacial periods. But, from what has been said 
above, it would appear that the facts point rather to shorter 
periods of advance and recession of the ice-front, analogous 
to those which are now in progress in the Alpine glaciers, as 
heretofore noted. That the interval between the two move- 
ments noted at Darrtown was comparatively short is evident 
from the fact that the fragments of wood found mingled 
with the till, both above the stratum of stratified material 
and below it, are identical in kind, and are in a similar state 
of preservation. This locality is about twenty miles back 
from the glacial margin. 

In the instances next mentioned of wood being found 
imbedded in glacial deposits the locality is still nearer the 
glacial margin, and, instead of being interglacial are pre- 
glacial—that is, the vegetable remains have glacial deposits 
over them but not under them. 


* See Fig. 148, p. 577. 


THE DATE OF THE GLACIAL PERIOD. 601 


A sycamore log was reported to me as found at Morgan- 
town, Morgan county, Ind., thirty feet below the surface. 
This is, however, in a stratified deposit, but one which was 
evidently formed in connection with the last stages of the 
Glacial period at that point. It is one quarter of a mile back 
from the little creek running through the village, and the. 
glaciai limit is but a few miles south, on the higher lands of 
Brown county. 

Again, near Seymour, Jackson county, Ind., logs of wood 
are reported as occasionally found in digging wells in the 
village at a depth of twenty feet below the surface. Sey- 
mour is on a glacial terrace, in the line of one of the largest 
glacial floods carrying off the melting torrents from the de- 
caying ice over a good part of southeastern Indiana. The wide 
terrace on which Seymour stands, and in which the logs are 
found, is about sixty feet above the present bed of the East 
Fork of White River, running through the place. Black- 
walnut logs are also mined from the banks of the river in 
low water. This instance is not probably decisive of the 
age of the buried wood, as the terrace may be the product 
of the so-called second Glacial period. Still, there can 
be no doubt that the most recent glacial advance extended 
to the borders of Brown county, which lies a little west of 
the locality just spoken of, and’ which is nearly in the lat- 
itude of Butler county, Ohio, alluded to in a previous para- 
graph. 

Another most decisive instance of vegetable remains in 
till near the margin occurs in Bigger township, in the south- 
eastern corner of Jennings county, Ind. Here Mr. Burchill 
reported to me the finding of wood im a well, twelve feet 
deep, in a hard blue clay which, from neighboring exposures, 
is, without dovbt, true till. On another farm, near by, wood 
was reported to me as found thirty feet below the surface in 
a well that failed to reach the rock at that depth. This is 
on as high land as there is in that region, and is about ten 
miles north of Madison, on the Ohio River, and about five 
hundred feet above it. 


602 THE ICE AGE IN NORTH AMERICA. 


Professor Borden * reports a well at Paris Crossing, in 
Jefferson county, about twelve miles southwest of the fore- 
going place, in blue-drift clay forty feet below the surface. 
The same authority also reports a well at Milan, near the 
summit of Ripley county, Ind., which is as far south as Cin- 
cinnati, and about twelve miles northeast from the river, with 
muck and wood fifty-four feet down in what is evidently 
the true till of the region. 

In Hamilton county, Ohio, the late Colonel Charles 
Whittlesey reported thirty-five wells containing muck-beds, 
leaves, or timber, from three hundred to five hundred feet 
above the Ohio River.t That at New Burlington is certainly 
in till. 

In Highland county, Professor Orton reports many cases 
of the occurrence of such vegetable deposits. In the village 
of Marshall, “eleven wells out of twenty reached a stratum 
of vegetable matter with leaves, branches, roots, and trunks 
of trees.” Marshall is on the very limit of the glaciated 
region. Similar instances were reported to me in the south- 
ern part of Highland county and in Clermont county. 

In Ross county, near Lattas, Mr. J. M. Connell reported 
to me finding wood in a well, situated very near the extreme 
limit of glacial action, and where it could not possibly have 
been brought into position by means of water. .The locality 
is four hundred and twenty-five feet (barometer) above the 
valley, just to the north, near Frankfort, and five hundred 
and twenty-five feet above the valley of the Scioto River at 
Chillicothe, ten miles to the east. The till is massed up 
against and upon the margin of a rocky plateau, here facing 
the north, in great quantities. The well described was in 
this marginal till upon the highest land, and passed through 
twelve feet of yellow clay, then through three or four feet 
of blue clay, then ten feet of yellow clay, then gravel for 
five feet. About thirteen feet below the surface there was 


* “Geological Report of Indiana,” 1875, p. 172. 
{ “Smithsonian Contributions to Knowledge,” 1869, pp. 13, 14. 


THE DATE OF THE GLACIAL PERIOD, 603 


found a log of wood three or four feet long and about three 
inches in diameter. This was in the blue clay, and was ac- 
companied with traces of muck. 

There is not space to mention the many other places 
where wood is reported in the modified drift filling what are 
perhaps preglacial channels serving as outlets of the melting 
glacial torrents, and which may therefore have been trans- 
ported a long distance from their native place. One such 
was reported to me in the valley of Raccoon Creek, in Gran- 
ville, Licking county, Ohio, and but a few miles from the 
glaciated border. This was found ninety-four feet below the 
surface of the terrace, which would bring it about forty feet 
below the present bed of the stream. A few miles farther 
up in this same valley so many red-cedar logs were formerly 
found beneath the glacial terraces along the valley, and the 
wood was so fresh, that a flourishing business was for a while 
carried on in manufacturing household utensils from them. 
Red cedar is not found in that region now, and these logs 
are probably of the same period with those described as 
found in true glacial till in Butler county, and which are so 
fresh as to preserve still the peculiar odor of the wood. 

Professor Collett reports that all through that portion of 
southwestern Indiana included within the glacial boundary 
there are found, from sixty to a hundred and twenty feet be- 
low the surface, peat, muck, rotted stumps, branches and 
leaves of trees, and that these accumulations sometimes occur 
through a thickness of from two to twenty feet. 

We may mention, also, as probably connected with the 
period of the ice-dam at Cincinnati, the well-preserved or- 
ganic remains found in the high-level terraces of various trib- 
utaries of the upper Ohio. In the vicinity of Morgantown, 
Professor I. C. White, as already noted, reports that, in the 
terraces which he connected with the period of the Cincinnati 
ice-dam, the leaves of cur common forest-trees are most beau- 
tifully preserved some distance below the surface, and that 
logs of wood in a semi-rotten condition were encountered 
seventy feet below the surface. At Carmichaels, in Wash- 


604 THE ICE AGE IN NORTH AMERICA. 


ington county, Pa., a log of wood was also reported to me 
as found in a situation similar to that described by Professor 
White, buried thirty feet in the sand of a corresponding » 
high-level terrace some miles back from the present bed of 
the Monongahela. Wood was also reported to me as found 
in a similar situation in terraces two hundred and fifty feet 
above the Alleghany River at Parker, Pa. The terraces 
there are many miles outside the glacial limit, but by their 
granite pebbles are unmistakably connected with the Glacial 
period. The wood was reported as dug from quicksand in 
a well two miles east of the river, and two hundred and fifty 
feet above it. iat : 

Another instance of wood which has been preserved in a 
deposit of the Glacial age is worthy of more minute descrip- 
tion. In this case I have the advantage of having found it 
myself. The locality is that of Teazes valley, Putnam county, 
W.Va. This valley runs from the Kanawha River a little 
below Charleston to the Ohio at the mouth of the Guyan- 
dotte near Huntington. The valley, as already described,* is 
clearly enough a remnant of early erosion, when the water 
of the upper Kanawha took that course to join the Ohio. 
The valley is very clearly marked, being about a mile wide, 
and from two hundred to three hundred feet lower than the 
hills on either side, and having a remarkably level floor 
throughout the greater part of its course. The bottom of 
the valley is filled throughout with a deposit of river-pebbles 
covered many feet with a mixture of sand and clayey loam. 
In some places this loam is from thirty to forty feet deep, 
extending for several miles without interruption, as at Long 
Level, about the middle of the valley.t Here a section about 
half a mile long and twenty-five feet deep shows at the top 
a stiff stratum of clay containing wood at a depth of seven 
feet. Immediately below is sand containing much iron, and 
cemented together by the infiltrations of the ore. The stra- 
tum above, containing the wood, had never been disturbed, 


* See p. 379. 1 See Fig. 111,on p. 380. 


THE DATE OF THE GLACIAL PERIOD. 605 


and the wood (a small specimen of a knot of some coniferous 
tree) is remarkably fresh in its whole appearance. It is 
scarcely possible that it should have remained in such a posi- 
tion during the immense period supposed by Mr. Croll to 
have elapsed since the glacial age. 

Many of these cases of subglacial vegetable accumula- 
tions are beneath or in deposits of the very earliest portion 
of the glacial period. Unquestionably of this age are those 
found in Jackson, Jennings and Jefferson counties, Indiana, 
and those found by Professor I. C. White in the terraces of 
the Monongahela River, which are now correlated with the 
earliest stages of the ice advance to the water-shed between 
the Great Lakes and the Ohio River. 

Farther north, notably in Mower County, Minnesota, a 
stratum of peat from eighteen inches to six or eight feet in 
thickness, with much wood, is very uniformly encountered 
in digging wells, the depth varying from twenty to fifty feet. 
“‘From all accounts it (the peat stratum) appears to be em- 
braced between glacial deposits of gravelly clay, and it 
seems to mark a period of interglacial conditions when 
coniferous trees and peat-mosses spread over the country . 
There are extensive marshes now existing in northern Min- 
nesota, mainly covered with ericaceous plants, with some 
cedar and tamaracks that are forming immense peat deposits. 
With an increase of the amount of moisture in the air such 
peaty accumulations would spread over much higher levels. 
A return of glacial conditions would bury such marshes be- 
low the deposits that are known as drift.’’* 

The observations of Professor Tarr upon the burial of 
forests and peat bogs by the recent advance of glaciers in 
Alaska are deserving of the most careful consideration in our 
interpretation of the significance of the facts which are being 
here detailed. 


*N.H. Winchell in “Geology of Minnesota,’’ vol. i of ‘Final Re- 
port,”’ p. 363. 


606 THE ICE AGE IN NORTH AMERICA. 


‘Along both the Atrevida and the Malaspina glacier mar- 
gins, the glacier and glacial deposits are advancing in forested 
regions and overspreading old soils, peat beds, and forests. 
When the process of present change is at an end there will 
be in this region soil beds and plant beds interbedded with 
glacial deposits, and all as the result of a sudden change in 
glacier-margin conditions. It requires no elaboration of this 
subject to make it clear that here is a hint of great significance 
in the interpretation of pleistocene deposits. In view of 
such phenomenaas those described above it is evident that the 
interpretation sometimes placed upon plant beds and soil beds 
intercalated in pleistocene deposits—namely, that they prove 


i 
| 


Fria. 154—Forest lately disturbed and about to be overwhelmed by an advancing Alaskan 
glacier. (Photo by Gilbert. ) 


separate glacial epochs—can hardly stand without the support 
of other and convincing evidence that the plant or soil bed 
interval was of long duration.’’* 

All this is in the region where the natural drainage is to the 
south; but, upon entering the northern water-shed, especially 
in the area now covered by the deposits of Lake Agassiz, in- 
terglacial deposits would seem necessarily to imply that the 


*R. 8. Tarr and B.S. Butler, ‘““The Yakutat Bay Region, Alaska,’’’ 
“U.S. Geological Survey,’’ ‘‘Professional Paper,’ 64, pp. 86, 87. 


THE DATE OF THE GLACIAL PERIOD. 607 


ice had melted back sufficiently to reopen the natural drain- 
age lines of the Red River Valley into Hudson Bay. Mr. 
Upham confesses that beds of vegetal deposit which are 
both underlaid and overlaid by till are very rarely found in 
northern Minnesota. Still, he supposes some such are found, 
and gives an exhaustive list of instances.* The two which 
he mentions as being in the area of Lake Agassiz are encount- 
ered in digging wells, first, at Barnesville, Clay county, where 
twelve feet of till was penetrated, then one foot of quicksand 
“containing several sticks of tamarack up to eight inches in 
diameter ; second, in Wilkin county, where the record is that 
till occupied the first eight feet, then a layer of gray sand 
one half an inch in thickness, then a much harder lower till 
for eighteen feet, which was underlaid by sandy black mud 
containing many snail-shells. But these two cases hardly 
seem sufficient to establish the theory, while the correspond- 
ing cases adduced by the Canadian geologists farther north 
are not described with sufficient minuteness to render their 
meaning unequivocal.t . 

Another class of phenomena bearing on the questions of 
the discontinuity and date of the great Ice age is to be found 
in the inclosed lake-basins lying between the Rocky Mount- 
ains and the Sierra Nevada, near the fortieth parallel. Nu- 
merous salt lakes now occupy this region. But it is evident, 
even upon hasty examination, that these are but insignificant 
remnants of those which formerly occupied it. Great Salt 
Lake is estimated to have contained at one period four hun- 
dred times its present volume of water. The terraces mark- 
ing its former limits are very distinctly visible, and are nine 
hundred feet above its present level. Lake Mono has several 
distinct terraces, the highest of which is six or seven hun- 
dred feet above the present level. Pyramid and North Car- 
son Lakes, in Nevada, are but the remnants of an immense 
salt lake extending from the Oregon boundary to latitude 


* “Minnesota Geological Report for 1879,” p. 48. 
+ ‘Report of Progress, Geological Survey of Canada, 1882-’84,” p. 414, C. 


608 THE ICE AGE IN NORTH AMERICA. 


38° 30’ south, a distance of two hundred and sixty miles. 
The Central Pacific Railroad is built through the bed of this 
lake for one hundred and sixty-five miles, from the vicinity 
of Golconda to that of Wadsworth. This ancient lake has 
been carefully surveyed and described by Mr. I. C. Russell, 
of the United States Geological Survey,* and has been named 


| (| il 
cw 


il} 


tl 


il 
in 


NT 


| ly il 


Fic. 155.—Sketch map of the Pacific coast, showing the outlines of the ancient lakes Bon- 
neville and Lahontan. (Le Conte.) 


* “Third Annual Report of the United States Geological Survey,” pp. 195= 
235, and “ Monograph XI,” 1885. 


THE DATE OF THE GLACIAL PERIOD. 609 


Lake Lanhontan, as that of which Great Salt Lake is the rem- 
nant was named Lake Bonneville, after the first explorers of 
the region. These basins have now no outlet to the sea. 
That of Lake Lahontan never had any; but, if the relative 
levels were the same at former times as now, Lake Bonne- 
ville at its greatest extent poured through Snake River into 
the Columbia. 

During the year 1890 Mr. Gilbert published the first volume 
of his monograph upon Lake Bonneville—the ancient enlarge- 
ment of Great Salt Lake, Utah—to which reference has just 
been made above. Mr. Gilbert estimates that at its maxi- 
mum stage the area of this lake was 19,750 square miles—that 
is, about ten times the present size of Great Salt Lake—and 
that its maximum depth was one thousand and fifty feet, as 
compared with about forty feet at. present. The climatic 
changes indicated by the studies of this ancient lake cor- 
respond closely with those indicated by Mr. Russell’s study 
of Lake Lahontan as detailed on page 607. Early in post- 
tertiary times there was a great rise in these lakes, though 
not sufficient by ninety feet to reach the passage through 
the Port Neuf River into the Snake. This first rise was fol- 
lowed by a long epoch of desiccation, during which it is prob- 
able the lakeentirely disappeared. Thisinter-lacustrine epoch 
was a long one, as is indicated: by the extent of the gravel 
deposits which were then laid down. After this there was a 
second rise, in which the water attained theheight of the pass- 
age from the Cache Valley to the Port Neuf, and then rapidly 
“cut a channel three hundred and seventy-five feet deep in the 
alluvium to a sill of limestone.”’ At this level (about six hun- 
dred feet above the Great Salt Lake) the water was held for a 
long time, forming what is known as the Provost shore-line. 
During the period of the Provost shore-line, glaciers descended 
from the Wahsatch Mountains, and left their moraines near 
the margin of the lake. 


610 THE ICE AGE IN NORTH AMERICA. 


In searching for an explanation of the former increase in. 
size of these bodies of water, the conditions of the Glacial 
period naturally present themselves as furnishing an ade- 
quate cause. Glaciers, however, never occupied much of the 
territory, being found only to a limited extent in the border- 
ing mountain-ranges. But the proximity of the glaciated 
region, and, indeed, the general conditions favoring the pro- 
duction of the Glacial period in North America, would be 
ample to produce the temporary enlargement of these lakes. 
A slight increase in precipitation, or a slight diminution of 
temperature, would either of them cause a rise in the water 
until the balance should be readjusted between the rainfall 
and the evaporation. 

It would seem that there is here also a significant record 
of an interglacial epoch, for the lakes have had two periods 
of increase, with an arid period intervening. During the 
first rise of the lakes, sediment to the extent of one hundred 
and fifty feet in thickness was deposited. There was then a 
dry period, in which the lakes were reduced to their present 
dimensions, or even smaller, when these first deposits were 
subjected to a period of erosion by surface streams, and partly 
covered with gravel. There was also upon it a deposit of 
great quantities of compact stony tufa precipitated from 
waters saturated with calcium carbonate. After the period 
of low water there was a subsequent reflooding of the basin, 
which reached a horizon thirty feet higher than the first. 
During this rise a deposit of thinolite took place, and of other 
substances whose position and character serve to note the 
changes. Subsequent to this rise the evaporation proceeded 
at an increased rate until the basins were completely desic- 
cated, and only began to refill within a period which Mr. 
Russell estimates to be less than three hundred years. All 
this, however, might have occurred within the space of a few 
thousand years, and does not, independently of other evidence, 
go far to establish the complete duality of the Ice age. 

As to the date of the expansion of these lakes, Mr. Rus- 
sell expresses it as his opinion that ‘the last desiccation oc- 


THE DATE OF THE GLACIAL PERIOD. * ‘Ot4 


curred certainly centuries, but probably not many thousands 
of years ago.”* This opinion is sustained by the fact that 
the erosion of present streams in these old beds is slight, and 
by the fact that in the cafions of the high Sierra, which were 
once occupied by glaciers, “the smooth surfaces. are still 
scored with fine, hair-like lines, and the eye fails to detect 
more than a trace of disintegration that has taken place since 
the surfaces received their polish and striation. . . . It seems 
reasonable to conclude that in a severe climate like that of 
the high Sierra it [the polish] could not remain unimpaired 
for more than a few centuries at the most.” To the same 
effect is the testimony of Mr. Gilbert as to the date of the 
last great extension of Lake Bonneville, of which he says: 
“The Bonneville shores are almost unmodified. Intersect- 
ing streams, it is true, have scored them and interrupted 
their continuity for brief spaces ; but the beating of the rain 
has hardly left a trace. The sea-cliffs still stand as they first 
stood, except that frost has wrought-upon their faces so as to 
erumble away a portion and make a low talus at the base. 
The embankments and beaches and bars are almost as perfect 
as though the lake had left them yesterday, and many of 
them rival in the symmetry and perfection of their contours 
the most elaborate work of the engineer. There are places 
where bowlders of quartzite or other enduring rock still re- 
tain the smooth, glistening surfaces which the waves scoured 
upon them by dashing against them the sands of the beach. 
“ When this preservation is compared with that of the low- 
est tertiary rocks of the region—the Pliocene beds to which 
King has given the name Humboldt—the difference is most 
impressive. The Pliocene shore-lines have disappeared. 
“The deposits are so indurated as to serve for building- 
stone. They have been upturned in many places by the up- 
lifting of mountains. Elsewhere they have been divided by 
faults, and the fragments, dissevered from their continuation 
in the valley, have been carried high up on the mountain- 


* “ Monograph XI,” p. 273. 


612 THE ICE AGE IN NORTH AMERICA. 


fianks, where erosion has carved them in typical mountain. 
forms. . . . The date of the Bonneville flood is the geologic 


yesterday, and, calling it yesterday, we may without exag- 


geration refer the Pliocene of Utah to the last decade the 
Eocene of the Colorado basin to the last century, and re- 
legate the laying of the Potsdam sandstone to prehistoric 
times.’’”* 

Mr. Gilbert believes that all this is attributable to sue- 
cessive elevations of the region, with an intervening subsidence. 


The evidence of a post-tertiary elevation is found ‘in the 
deeply submerged channel near Cape Mendicino,” while the 


proofs of asubsequent depression “are supplied by the marine 
terraces of the Columbia and Fraser basin, and by the post- 
tertiary beds of the California coast recently described by 
Dall as rising gradually toward the south until at Monterey 
and southward they are about six hundred feet above the 
sea-level. . . . The uplifting of the Wahsatch range 
is shown to be still in progress by post-Bonneville fault- 
scraps.’ Mr. Gilbert’s study of the horse-remains found in 
the region would assign them to the period of ‘the upper- 
most of the Lahontan and Bonneville beds,” thus transferring 
their geological horizon from the late tertiary to the latter 
part of the glacial period. 

It is interesting to note, in connection with these old 
lake-basins, that the Dead Sea in Palestine probably has a 
similar relation to the development of glaciers in the Le- 
banon Mountains, and Russell is of the opinion that the 
gravel-deposits reported at various elevations about it are, 
like those of Lakes Bonneville and Lahontan, records of 
the Glacial period. 

My own investigations upon the glacial deposits of the 
Lebanon Mountains, however, showed that there had never 
been any glaciers reaching the head-waters of the Jordan 
Valley; but there was a glacier descending from the highest 

*“‘Second Annual Report of the U.S. Geological Survey,’’ p. 188. 


} ‘‘Jordan-Arabah and the Dead Sea, ‘Geological Magazine,’’ 
vol. 5, pp. 337, 387. 


} 
4 
; 
% 
aq 
1 

4 

’ 


THE DATE OF THE GLACIAL PERIOD. 613 


summit of the mountains about thirty miles northeast of 
Beirut and depositing an extensive moraine upon which the 
present grove of the Cedars of Lebanon are growing. The 
height of the summit is a little over 10,000 feet, and the glacier 
descended to the Ievel of 5,000 feet above the sea. The mo- 
raine is about three miles broad at the foot, and extends five 
miles back toward the summit, and is several hundred feet 
thick at its termination. Though not directly connected 
with the Jordan Valley the climatic conditions accompanying 
the formation of this glacier doubtless extended a long dis- 
tance in that direction and so may account for the enlarge- 
ment of the Dead Sea indicated by the abandoned shore- 
lines, the most persistent of which is 650 feet above its present 
level. (See “Records of the Past,’ July, 1906, pp. 195-204.) 

Such are, in brief, the considerations which seem to make 
it proper to hesitate before recognizing the theory of discon- 
tinuous pleistocene epochs in America as an established 
doctrine to be taught. The most of the facts adduced to 
support the theory of distinct epochs are capable of explana- 
tion on the theory of but one epoch with the natural oscil- 
lations accompanying the retreat of so vast an ice-front. It 
seems more likely that the retreat from the extreme border 
of the glaciated area to the line of the moraines of the several 
later glacial epochs was analogous to that from one to another 
of the successive twelve or thirteen receding concentric lines of 
moraine appearing on our general map and on that of 
Minnesota made from the latest reports, than that successive 
glacial advances should so nearly duplicate the first as it is 
made to do on the other theory. 

After a painstaking discussion of the whole subject, 
Professor Prestwich expresses it as his opinion that— 


The time required for the formation and duration of the 
great ice-sheets in Europe and America (the Glacial period) 
need not, after making all allowances, have extended be- 
yond fifteen thousand to twenty-five thousand years, instead 


614 THE ICE AGE IN NORTH AMERICA. 


of the one hundred and sixty thousand years or more which 
have been claimed. | 

The adoption by some of a term of eighty thousand 
years for the post-Glacial period has been very much the 
result of the belief that no shorter time would account for 
the excavation of the valleys supposed to have been formed 
during this period, on the assumption of a “‘uniformitarian”’ 
rate of denudation. Thisrate, based on observations made 
at the present time, always seemed to me open to grave 
objections, and in this belief subsequent experience has 
confirmed me. . . . and I would for the same reasons limit 
the time of the so-called post-Glacial period, or of the 
melting away of the ice-sheet, to from eight thousand to 
ten thousand years or less.* 


Summary. — The terrestrial facts brought to light as 
clearly. bearing on the question of the date of the glacial era 
are much more numerous than they have heretofore been 
supposed to be. Scarcely more than a beginning has been 
made in their collection and interpretation ; but, as far as we 
have gone, the investigation has been most interesting and 
suggestive. For the most part these facts imply a later date 
for the Glacial period than the current astronomical theory 
would admit, and so far they go to disprove that theory. 

The glaciated area seems a vastly newer country than 
the unglaciated. In the glaciated region the waterfalls have 
hardly more than begun to recede; the valleys and gorges 
are both narrower and shallower than in the unglaciated por- 


tion of the country ; the lakes and kettle-holes are yet unfilled 


with sediment, and their outlets have not yet to any great 
extent lowered the drainage lines; the striated rocks have 
resisted disintegration to a remarkable degree during post-gla- 
cial times, and the moraines and kames have retained their 
original forms with little signs of erosion. Niagara Falls 
and the Falls of St. Anthony can neither of them be over 
ten thousand years old. The waves of Lake Michigan can 


* See Prestwich’s “ Geology,” vol. ii, pp. 533, 534. 


THE DATE OF THE GLACIAL PERIOD. 615 


not have washed its shore for a much longer time, and the 
smaller lakes and kettle-holes of New England and the North- 
west can not have existed for the indefinite periods some- 
times said to have elapsed since the glacial era, while eternity 
itself is scarcely long enough for the development of-species 
if the rate of change is no greater than is implied if man and 
his companions both of the animal and vegetable kingdom 
were substantially what they are now as long ago as the date 
often assigned to the great Ice age. 

But while approximate limits are already set to giacial 
chronology, the field is still open for an indefinite amount of 
painstaking inquiry. Local observers may now profitably 
spend as much time upon a single river-valley or in a single 
county as has yet been spent upon the whole field between 
Cape Cod and the Mississippi. 


Fie. 156—Bowlder bed at Pocatello, Idaho, where the Port Neuf river debouches upon 
the Snake river plain. These bowlders were brought down to their present position 
by the torrential floods which followed the overflow of Lake Bonneville, described 
on pages 609 and 704. 


CHAPTER XXI. 


MAN AND THE GLACIAL PERIOD. 


Wuen, in 1863, Sir Charles Lyell published his great 
work upon “The coaenis of Man,” the general public was 
somewhat surprised to find that one tenia and sixty pages, 
or almost one third of the entire volume, was devoted toa 
discussion of glacial phenomena. This course was justified 
by the fact that rough-stone implements, undoubtedly of 
human ed EG had recently been found in deposits 


BIG. 1é 7.—Typical collection of Gulealithie implements, 
reduced in photograph to one eighth natural size. 
The four in the lower row are of “argillite from the 
gravel in Trenton, New Jersey. The smal! one, a lit- 
tle above the lower row is from Moustier, France. 
The large one in the middle row is from’ Amiens, 
France. The two at the left of it are from France. 
The one at the right is from upver Egypt. These 
are all of flint. The four in the upper row, a core of 
flint and flakes of flint. 


supposed to be of 
glacial age in north- 
ern France and 
southern England, 
making the question 
of the antiquity of 
man one no longer 
of mere history or 
archeology, but of 
glacial geology. A 
further reason for 
the prominence giy- 
en to the discussion 
of purely glacial 
questions in Sir 
Charles Lyell’s work 
was the comparative 
ignorance, at that 


time, of the character, extent, and significance of glacial phe- 
nomena. The discussions running through the previous 


MAN AND THE GLACIAL PERIOD. 617 


chapters of the present volume prepare the way for readily 
understanding even a summary statement of the facts already 
discovered con- . | 
necting man 
with the Gla- 
cial period in 
North Ameri- 
ca. We may, 
therefore, with- 
out further pre- 
liminaries, at 
once address 
ourselves to the 
subject, and de- 
scribe the con- 


ditionsin which 


implements of Fic. 158.—Reverse side of 2 implements shown in the preced- 
ing figure. 


3 ee a =. ao 
human manu- 

facture have been found in the glacial deposits on this con- 
tinent. 

At the outset two questions arise in the discussion: 1. 
Whether the implements found are really artificial and gen- 
uine. 2. Whether the deposits in, which they occur really 
belong to the Glacial period. 

1. That the implements are of human origin is evident 
from close inspection, and comparison with natural frag- 
ments. Flint and some other species of stone are specially 
adapted for the manufacture of implements, because of their 
hardness, and of the facility with which flakes can be struck 
from them so as to leave a sharp, cutting edge. Many nat- 
urai forms of flint can be appropriated as useful tools with- 
out modification. The action of frost upon a flint nodule, 
or the accidental falling of a stone upon it, may produce a 
sharp-edged fragment of convenient size for use. But the 
proof of human workmanship consists in a series of fractures 
of such character and so arranged that they irresistibly indi- 
cate design. One prominent feature of an artificial flake is 


618 THE ICE AGE IN NORTH AMERICA. 


the so-called “bulb of percussion.”” When a sharp, well- 
directed blow falls upon a flint nodule, the force distributes 
itself in such a way that, in the immediate vicinity of the 
blow, a slight hollow is made in the nodule, and the corre- 
sponding bulb in the flake is shaped somewhat like the ball of 
one’s thumb, while the rest of the flake is straight and regu- 
lar in form. It is possible that this bulb of percussion may 
sometimes be made by the accidental falling of one stone 
upon another; but such an occurrence must, in the nature of 
the case, be very rare, since the blow must be delivered at 
exactly the right point and at the proper angle, in order to 
produce the right result. The chances are exceedingly small 
that such a blow should be delivered except by design. 

As to the arrangement of the fractures, the evidence is 
even more conclusive. A simple cutting edge may readily 
be formed by natural forces; but, in the implements that 
are regarded as of human origin, the arrangement of the fract- 
ures producing the cutting edge is so complicated as to pre- 
clude the supposition that they are undesigned. Nor does it 
require many secondary chippings to establish the artificial 
origin of an implement. A half-dozen subsidiary chippings 
on a natural flint pebble, serving to bring it into a symmetry 
such as would serve the purpose of a human being, is evi- 
dence enough. A trained eye has no difficulty in distin- 
guishing, at a glance, between natural forms and artificial 
forms. ‘The loose statements asserting that there is occasion 
for grave doubt as to whether the mass of so-called palso- 
lithic implements are really implements can only be made, 
and be believed, by those who have given little personal at- 
tention to the subject. 

That I may not seem to place too much confidence in 
my own judgment in this all-important matter, I have 
thought it best to secure the opinion, concerning the imple- 
ments of which this chapter treats, of one who has had ample 
opportunity to examine them and compare them with those 
from other parts of the world, and whose authority would 
be second to that of none. I therefore addressed a letter 


MAN AND THE GLACIAL PERIOD. 619 


to Professor Henry W. Haynes, of Boston, requesting his 

opinion on the subject. His reply I will, with his consent, 

reproduce.* 3 
Boston, January 23, 1889. 


DEAR Proressor Wricgut: You ask for my opinion in 
regard to the artificial character of the quartz fragments dis- 
covered by Miss Babbitt, at Little Falls, Minn., as well as of 
the argillite objects discovered by Dr. Abbott, at Trenton, 
N. J., and those still more recently obtained by Dr. Metz and 
Mr. Cresson. In replying to your inquiry I must premise by 
stating that, although I have had abundant opportunity of 
studying all these different objects, I have only visited one of 
the localities where they were found—that is Trenton, N. J.— 
where, as you know, I was accompanied by yourself, Professor 
Boyd Dawkins, and the late Professor Henry Carvill Lewis, in 
my examination of the region ; but I had previously visited 
many localities in Europe, where paleolithic implements have 
been discovered ; and I have myself found many. Several 
years of study in that country have made me familiar with 
the cleavage of flint, and the method of fabricating rudely 
chipped implements. Subsequently, in this country, for a 
still longer period, I have given much attention to the tools 
and weapons of the Indians, and the different materials of 


* I would remark that Professor Haynes’s private collection of paleoliths is 
one of the largest in this country, and abounds in representatives from every 
locality where they have been found. The following is a list of his publications 
upon the subject: Silex Acheuléeus de VEgypte, “ Bull. de la Soc. d’Anthrop. 
de Paris,” 3d ser., vol. i, p. 389; “The Fossil Man,” “ Popular Science Monthly,” 
July, 1880, p. 350; “The Egyptian Stone Age,” “Nation,” January 27, 1881; 
“Discovery of Paleolithic Implements in Egypt,” “ Memoirs of the American 
Academy of Arts and Sciences,” vol. x, p.357; “ The Argillite Implements,” ete. 
“Proceedings of the Boston Society of Natural History,” vol. xxi, p. 1382; “ The 
Paleolithic Man,” “ American Antiquarian,” vol. vi, p. 187; ‘The Stone Age in 
Prehistoric Archeology,” ‘ Science,’’ vol. iv, pp. 469, 522; “Man in the Stone 
Age,” “Science,” vol. v, p. 43; “The Bow and Arrow unknown to Paleolithic 
Man,” “Proceedings of the Boston Society of Natural History,” vol. xxiii, p. 
269; “‘ Paleolithic Man in London and its Neighborhood,” “ Science,” vol. ix, 
p- 221; “Opinion on Paleolithics,” ‘‘ American Antiquarian,” vol. x, p. 125; 
“The Prehistoric Archeology of North America”; ‘ Narrative and Critical 
History of America,” vol. i. pp. 329-368. 


620 THE ICE AGE IN NORTH AMERICA. 


which they were fashioned, in a great many different localities. 
I think, therefore, I have gained an acquaintance with the 
character of the fracture of very many different kinds of stone, 
which have been broken by man intentionally for his use as tools. 
I say this, because I have always.been in the habit of compar- 
ing and contrasting such broken stones with those whose fract- 
ure had been occasioned by different natural forces, so that 
I might learn the resemblances and the differences between. 
them. ‘This is a subject which it is difficult to treat of satis- 
factorily in writing, as it is so much an affair of ocular dem- 
onstration. ‘These little minute differences and peculiarities 
are very palpable, when they are pointed out, although a geolo- © 
gist, or a mineralogist, who is perfectly familiar with the ma- 
terial, but who may have had little or no training as an arche- 
ologist, may have failed to notice them. The whole subject 
is one solely for the judgment of the expert; and when a 
heap of. broken stones, characterized by a general external re- 
semblance, ‘has been submitted to the determination of several 
trained archeologists, as I have often seen done in Europe, 

there has been no difference of opinion among them as to 
which were natural and which were artificial forms. Of course, 

if the broken stones have been afterward subjected to the action. 
of running water, so as to produce a general wearing away of the 
edges of the fractures, the difficulty of discriminating becomes 
much greater. In such cases only a very practiced eye can de- 
cide; and the opinion of any man, however eminent he may 

be in other departments of knowledge, who has not had great 
archeological experience, is practically worthless. 

It was in the autumn of 1880 when we visited Trenton, 
and at that time I found a few paleoliths there myself; after-. 
ward Dr. Abbott gave me quite a collection of his own find- 
ing, which I have had ever.since in my possession, and have 
continually studied. So in repeated instances have I examined 
his great collection in the Peabody Museum. At a meeting 
of the Boston Society of Natural History, in January, 1881, 
I expressed my conviction as to the artificial character of 
these argillite implements, notwithstanding the fact that the. 
coarseness of their material precludes their ever equaling in 
workmanship the flint implements of Europe. My subsequent 


MAN AND THE GLACIAL PERIOD. §21 


study of the same and other objects from that locality has only 
served to strengthen the opinion I then expressed. 

The quartzes discovered by Miss Babbitt I first saw in the 
autumn of 1882, when she forwarded a box of them for my 
inspection. The following summer she sent me another lot 
of them on deposit ; both of these have been in my possession 
ever since, and have been repeatedly studied by me. I have 
also examined the collection she sent to the Peabody Museum. 
I should judge that I have thus had at least a hundred and fifty 
of these pieces of quartz brought under my careful scrutiny. 
Miss Babbitt had no knowledge of archeology, and her fanci- 
ful speculations in regard to the supposed use that had been, 
or might have been, made of certain fragments, which she dig- 
nified with the name of types, have tended to obscure the real 
presence among them of some well-marked examples of palezo- 
lithic implements. I wrote her my opinion in regard to them, 
and a portion of my letter was printed by her in connection 
with her articles on ‘‘ Vestiges of Glacial Man in Minnesota,” 
in the June and July numbers of the “‘ American Naturalist ” 
for 1884. In this I stated that ‘‘ some of them I believe to be 
implements ; many are only chips struck off in shaping imple- 
ments, and refuse pieces left from such work ; many are natural 
forms, and one or two rolled pebbles. . . . I trace clearly upon 
your implements such a preparation of them (i. e., by having 
had most of their projections battered off by another stone) 
for holding them in the hand. Many of yours bear evident 
marks of use in the worn condition of portions of their edges 
or of their points.” All my subsequent study of them has 
tended to confirm this opinion, and I can only repeat my 
assured conviction that these rudely fashioned implements, and 
the fragments that were found with them, whose edges are 
still as sharp as when they were first struck off, are the ‘‘ prod- 
uct of an intentional breaking by the hand of man and not 
the result of natural causes.” 

It is important to notice that among the hundreds of 
paleolithic implements discovered by Dr. Abbott, at Trenton, 
a few made of quartz are so absolutely similar to those found by 
Miss Babbitt, and now either in my possession or at the Peabody 
Museum, that it would be impossible to distinguish them apart. 


622 THE ICE AGE IN NORTH AMERICA. 


The implements discovered by Dr. Metz and Mr. Cresson, 
and now also in the Peabody Museum, are as palpable human 
tools as any I ever saw, although, on account of the inferior 
quality of the material of which they are made, they are not 
equal in excellence to similar objects of like age in Europe. 
I can not conceive of any one, who has a proper acquaintance 
with the subject, entertaining a moment’s question as to their 
artificial character. 

By this frank expression of my conviction, I have en- 
deavored, as best I can, to answer your questions, and remain, 


Sincerely yours, 


HENRY W. HAYNEs. 


A still further question with regard to these implements 
relates to their genuineness. Their present commercial value 
offers temptation for their forgery, and there can be no doubt 
that hundreds of implements of the very earliest type have 
been made to order and sold to unsuspecting collectors. 
Still, however perfect these forgeries may be in form, only 
the inexperienced and the unwary can be deceived by them. 
There are certain chemical changes affecting the superficial 
aspect of an implement which time only can produce. A 
fresh flake can readily be distinguished by a practiced eye. 
As yet not enough is known of the rapidity with which 
weathering takes place under stated conditions, to make it a 
basis for chronological calculation; but the difference be- — 
tween a very ancient implement and a very recent one is 
easily enough detected. It isa significant fact early observed, 
and supported by all recent discoveries (if we except those 
in California, of which further mention will be made), that 
in America as in Europe the implements found in glacial 
deposits are all of a peculiar type. None but implements of 
stone have been found in these deposits; and of the stone 
implements none are polished and smooth, but all are rude 
in form and roughly flaked. From their evident antiquity, 
as will be shown a little later, these rough stone implements 
are called palwolithic (Gr. mandaws “old,” and dios, 


MAN AND THE GLACIAL PERIOD. 623 


“stone ”); while the later stone implements are classified 
as neolithic (Gr. véos, “ new,” and AlGos, “ stone”). 

Paleolithic implements are said to be old, however, not 
because of any inelastic theory of evolution, implying that 
people using rude arts always precede those who are more 
skilled, but the age of these implements as a class is deter- 
mined by the fact that they have been found in undisturbed 
glacial deposits or under other geological conditions showing 
their antiquity. Such implements are unquestionably older 
than others found upon the surface ; and, in their case, the 
evidence of great age is definite and conclusive, while the 
antiquity of the implements found upon the surface is sub- 
ject to more or less of doubt. If man inhabited the region 
bordering upon the great ice-sheet when it extended to its 
farthest limits, his implements should be found near the sur- 
face of the ground outside those limits; and such might be 
of even greater age than those which are found in stratified 
glacial deposits themselves. Also, as the ice receded, it is to 
be expected that man would follow it in its slow recession 
(as the Eskimo does to-day in Greenland) and that his imple- 
ments would be lost upon the surface. How long he may 
have continued thus to use implements of paleolithic type 
can not readily be determined. Mr. Thomas Wilson, of the 
Smithsonian Institution, has already collected, or had reported 
to him, many thousand implements of the paleolithic type 
found in various parts of North America. In almost all 
cases these were found upon the surface, and there is no 
means of determining their age except from their general 
weathered appearance, as implements of the same forms have 
been made and used all through the Stone age. 

About the year 1860 interest in the subject of man’s an- 
tiquity received a new and definite impulse in connection 
with the discoveries of Boucher de Perthes in northeastern 
France. As long ago as 1841 this indefatigable investigator 
discovered rudely fashioned stone implements in high gravel 
terraces along the valley of the Somme at Abbeville. An 
account of his discoveries was published in 1846. Little at- 


624 THE ICE AGE IN NORTH AMERICA. 


tention was paid to the matter, however, until 1859, when 
Dr. Falconer, Mr. Prestwich, Mr. Evans, Sir Charles Lyell; 
and other English geologists visited the locality, and brought 
the discovery more fully to public attention. Full deserip- 
tions may be found in the works of Sir Charles Lyell on 
“The Antiquity of Man” * and Sir John Lubbock on “ 4 
historic Times.” + 

The river Somme is a small stream, about one hundred 
miles in length, occupying a broad, deep trough, about a mile 
in width at Abbeville, worn out 4 chalk formations. Upon 
the sides of this trough, up to an elevation of something over 
one hundred feet, there are remnants of gravel terraces, 
formed when the river flowed at a correspondingly higher 
level than now. ‘These terraces consist wholly of material 
local to the Somme Valley, and not in any degree of foreign — 
drift. The implements found are imbedded in undisturbed 
strata of this gravel. In connection with them, also, there 
are found bones of many animals now extinct, those of the 
Elephas primigenius being specially numerous. 

Soon after the confirmation by these eminent authorities 
of the important discoveries made by Boucher de Perthes, 
examination showed that the same class of rudely formed 
chipped stone implements occurred also in gravel-deposits in 
southern England. The relation of these deposits to the 
streams was similar to that of those in the valleys of north- 
eastern France. Indeed, a discovery of paleeoliths had been 
made in England more than fifty years before, in the very 
first years of the century; but its importance was not sus- 
pected until Boucher de Perthes’s discoveries called attention 
anew to the subject. Mr. John Frere had, in the year 1800, 
described a collection of flints found at Hoxne near Diss, in 
Suffolk, England, specimens of which were preserved in the 
British Museum and in the collections of the Society of Anti- 
quaries. These proved to be of the same type with those 
found at Abbeville, and the deposits are of corresponding 


* P. 106 ef seq. + P. 342 et seq. 


MAN AND THE GLACIAL PERIOD. 625 


character in the two places. Similar discoveries were also 
made at various other places in southeastern England, the 
most important being in the vicinity of Southampton and the 
Isle of Wight. 

When we come to examine these European deposits with 
reference to their relation to the Glacial period, it must be 
confessed that we enter a rather obscure field. The region 
in Europe in which paleolithic implements have been found 
imbedded in the gravel of river terraces is peculiar for its 
limitation. In Great Britain none have been found north of 
a line connecting the British Channel with the Wash, and 
on the Continent these discoveries are all outside the direct 
action of glaciers either from the Scandinavian or the Swiss 
fields. Hence it will be seen that the problem is quite dif- 
ferent from that which we shall presently study in America, 
and is far more complicated. Still, the same rule holds good 
in one country as in the other, that the higher terraces are 
older than the lower, and there can be little doubt that the 
terraces in which paloliths are found are directly or in- 
directly of glacial origin. But the data for estimating the 
time which has elapsed since the deposition by glacial tor- 
rents of the high-level gravels in the valley of the Somme 
and in southern England are much less clear than in this 
country. 

The year 1875 marks an epoch in the prehistoric arche- 
ology of North America, since it was then that Dr. C. C. 
Abbott’s attention was first specially attracted to the imple- 
ments of a paleolithic type found in the neighborhood of his 
residence in Trenton, N. J. Whether these implements were 
from the surface, or from the gravel which underlies the city, 
was at first uncertain, for they had then been found only in 
the talus of the gravel-banks. But Dr. Abbott’s residence 
at .Trenton enabled him during the succeeding year to give 
attention to the numerous fresh exposures of the gravel 
made by railroad and other excavations; and he was soon 
rewarded for his pains by finding several chipped imple- 
ments in undisturbed strata of gravel, some of which were as 


626 THE ICE AGE IN NORTH AMERICA. 


much as twelve feet below the surface. Since that time he 
. has continued to 
make similar 
discoveries at 
various _ inter- 
vals. In 1888 
he had already 
found four hun- 
dred implements 
of the paleeolith- 
ic type at Tren- 
ton, sixty of 
which had been 
taken from re- 
corded depths in 
the gravel, two 
hundred and fif- 
ty from the talus 
at the bluff fac- 
ing the river, and 
the remainder 
from the surface, 
or derived from 
collectors who 
did not record 
the positions 
or circumstances 
under which 


they were found. 


Fic. 159.—Face view of argillite implement, found by Dr. C. C. % 
Abbott, ee fblnit aed’ New vivo t in dank three In 1878 Profess 
feet from ace of bluff, and twenty-two feet from the sur- . 
face (No. 10,985). (Putnam. )* or J. D. Whit- 


* This cut, together with the following ones credited to him, Professor F. 
W. Putnam has kindly furnished me, for use in advance of publication, from 
his elaborate report upon the palzolithic implements in the Peabody Museum of 
American Archeology and Ethnology, Cambridge, Mass. The numbers in paren- 
theses are those on the implements, and correspond to the catalogue of the 
museum. The figures are natural size. 


MAN AND THE GLACIAL PERIOD. 627 


uey, with Mr. Lucien Carr, of the Peabody Museum, Cam- 
bridge, visited Dr. Abbott, and they together found several 
palzeolithic implements in the undisturbed gravel.* And 
again, in 1879 and 1880, Professor F. W. Putnam was with 


Dr. Abbott when specimens 
were found in similar condi- 
tions. Mr. Carr describes the 
situation as follows: It was “in 
a fresh exposure made by a re- 
cent heavy storm, and was about 
three feet deep in the ground, 
and one foot in from the perpen- 
dicular face of this newly ex- 
posed surface.” Professor Put- 
nam gives the following descrip- 
tion of his discoveries: 


A short distance from Dr. 
Abbott’s house, and very near 
where the Trenton gravel joins 
the marine gravel, there is a deep 
gully through which flows a small 
brook. In this gully the gravel- 
bank is constantly washing away, 
and presenting new surface ex- 
posures. After a heavy rain in 
June, 1879, I visited the spot 
with Dr. Abbott and his son. 
Here I noticed a small bowlder 
of about six or eight inches in 
diameter, projecting an inch or 
two from the face of the bank 
about four feet from the surface 
of the soil above ; I worked the 
stone from the gravel in which 


Fie. 160.—Side view of the preceding. 
(Putnam.) 


it was firmly imbedded and drew it out. At the back part of 
the cavity thus made I noticed the pointed end of a stone, and 


* “ Proceedings of the Boston Society of Natural History,” vol. xxi, p. 145 


628 THE ICE AGE IN NORTH AMERICA. 


after working it up and down a few times, so as to loosen the. 


gravel about it, I drew out the implement now exhibited, 


a b 


ome 


rit 
sh 


“a 


——_ 


Fie. 161.—Argillite implement found by Dr. C. C. Abbott, March, 1879, at A. K. Rowan’s: 
farm, Trenton, New Jersey, in gravel sixteen feet from surface. a, face view ; 3, 
side view. (No. 11,286.) (Putnam.) 


On the same day I discovered a second specimen in place 
eight feet from the surface, and Dr. Abbott’s son Richard 
found another about four feet from the surface. These three 
specimens were found within twenty or thirty feet of each 
other, after a heavy shower had made the most favorable con- 
ditions for their discovery. 


My own first visit to the locality was in November, 1880, 
in company with Professors W. Boyd Dawkins, Henry W. 
Haynes, and H. Carvill Lewis, when we were conducted by 
Dr. Abbott to the various localities favorable for investiga- 


tion. Professor Lewis and myself also repeatedly visited the 


MAN AND THE GLACIAL PERIOD. 629 


locality afterward. But neither of us was ever so fortunate 
as to find a paleolithic implement in place, or even in the 
fresh talus of the bluff facing the river. As our experience 
is that of many others who have visited the locality, and 
hence of attempts in some quarters to throw doubts upon the 
genuineness of Dr. Abbott’s discoveries, it is worth while to 
record that Professors Dawkins and Haynes independently 


Fic. 162.—Chipped pebble—black chert, found by Dr. C. C. Abbott, 1876, near the site 
of Lutheran church, Trenton, New Jersey, in gravel six feet below the surface. a, 
face view ; 6, side view. (No. 10,986.) (Putnam.) 


found implements in the talus over which we had passed a 
moment or two before; but, as the attention of Professor 
Lewis and myself was directed chiefly to the geological prob- 
lems relating to the character and age of the deposit itself, 
our failure to discover implements where trained eyes saw 
them but illustrates the limitations of observers. To distin- 
guish a roughly flaked human implement in a bed of gravel 
and pebbles where the ratio of artificial flakes to the natural 
forms is as one to a million, is like finding a needle in a hay- 
mow. Hence negative evidence, or a failure of particular 


630 THE ICE AGE IN NORTH AMERICA. 


observers to find implements, has very little weight in 
discrediting the testimony of others who have been more 
successful. : | 

The acrimonious controversy over the genuineness of 
these implements of supposed glacial age was finally put to 
rest by a fortunate discovery made by Mr. Ernest Volk, while 
working under the auspices of the Peabody Museum of Cam- 
bridge, Mass. The discovery was that of a human femur, in 
undisturbed gravel twenty feet below the surface, and be- 
neath a thick deposit of crossbedded coarse gravel which 
unquestionably belongs to the glacial era. The accompanying 
illustration of the gravel pit in which this was found lies in 
the same bank shown in the illustration on p. 521, but after 
the gravel bank had been excavated 100 feet or more farther 
back from the river. 

Accepting as now beyond question that. these palzeolithic 
implements ‘at Trenton occur in undisturbed strata of the — 
gravel, of which the evidence just given would seem to be 
sufficient, the question of the archzologist as to the age of 
the deposit is asked of the geologist, and it is for him tu 
answer. In the light of the preceding chapters, a ready an- 
swer is found to this question. The city of Trenton is built 
upon a horseshoe-shaped gravel-deposit which is about three 
miles in diameter, extending back about that distance to the 
east from the present river. This deposit is somewhat lower 
around its inland boundary than along the river. The prongs 
of this horseshoe rest, one at Trenton, and the other two 
miles below, just north of the house of Dr. Abbott. This 
gravel is thus described by Professor Shaler : 


The general structure of the mass is neither that of ordi- 
nary bowlder-clay nor of stratified gravels, such as are formed 
by the complete rearrangement by water of the elements of 
simple drift-deposits. It is made up of bowlders, pebbles, and 
sand,..varying in size from masses containing one hundred 
cubic feet or more to the finest sand of the ordinary sea-beach- 


MAN AND THE GLACIAL PERIOD. 631 


Fic. 163.—Typical section of the Trenton gravel in which the implements described in 
the text are found. Note the distinct stratification and the large angular bowlder 
near the surface, showing the presence of floating ice, since by no other means 
could such a bowlder get into sucha position as here found. The elevation of the 
surface is here 50 feet and is about half a mile back from the river edge of the bluff. 
Perpendicular exposure is here between 30 and 40 feet. 

(Photograph by Abbott.) 


es. There is little trace of true clay in the deposit ; there is 
rarely enough to give the least trace of cementation to the 
masses. The various elements are rather confusedly arranged ; 
the large bowlders not being grouped on any particular level, 
and their major axes not always distinctly coinciding with the 
horizon. All the pebbles and bowlders, so far as observed, -are 
smooth and water-worn, a careful search having failed to show 
evidence of distinct glacial scratching or polishing on their 
surfaces. The type of pebble is the subovate or discoidal, 
_and though many depart from this form, yet nearly all ob- 
served by me had been worn so as to show that their shape 
had been determined. by running water. ,The materials com- 
prising the deposit are very varied, but all I observed could 
apparently with reason be supposed to have come from the 


Fig. 164—Graveldepositat Trenton, N.J., where Mr. Volk found a human femurin Dec- 
ember, 1899. The arrow points to the spot where the femur was discovered. 
(Courtesy of Records of the Past. ) ; 


MAN AND THE GLACIAL PERIOD. 633 


extensive valley ot the river near which they lie, except per- 
haps the fragments of some rather rare hypogene rocks.* 


It is now settled that the rocks from which these beds 
were derived are all in place in the upper Delaware Valley.t 

The distinction between the river-gravel and that which 
overlies the larger part of southern New Jersey is marked in 
several ways. The Trenton gravel is much coarser than the 
genera! deposit, it is also largely composed of fresher looking 
and softer pebbles, showing that it has been subject to much 
less abrasion than the other, and that it is of more recent 
age; it is alsc limited to the river-valley, and finally is not 
overlaid by the Philadelphia brick-clay which, so far as it 
extends, rests unconformably upon the general deposit of 
gravel. The general deposit of gravel in this region is com- 
posed almost exclusively of small, well-rounded pebbles of 
quartz and of hard limestone which “are not fresh looking, 
but are eaten and weather-worn by age.” 


Fie. 128.—Section across the Delaware River at Trenton, New Jersey. a, a, Philadelphia 
red gravel and brick clay (McGee’s Columbia deposit) ; 6, 6, Trenton gravel, in which 
the implements are found; c, present flood-plain of the Delaware River. (After 
Lewis.) (In Abbott’s ‘‘ Primitive Industry.”’) 


The elevation of this implement-bearing gravel at Tren- 
ton is not far from forty feet above the present high-water 
limit; and Trenton is now at the head of tide-water. These 
gravels are continuous as a terrace all along up the river. As 
one ascends the river, however, their height (at least below 
the Water-Gap) is reduced to fifteen or twenty feet above 
the present flood-plain. 

But most significant of all the facts indicated are the 
character and position of the Philadelphia red gravel and 
brick-clay. This also is confined to the river-valley and its 
tributaries, and rests unconformably upon the older gravel 


* “Report of Peabody Museum,’’ vol. ii, 1876-’79, pp. 44-47. 


Tt ‘‘New Jersey Report for 1877,’’ p. 21; Lewis on ‘‘The Trenton 
Gravel,”’ p. 5. 


634 THE ICE AGE IN NORTH AMERICA. 


formations, rising to a height of one hundred and fifty feet 
above the river, and there ceasing. This elevation relative 
to the river is maintained as far up as Easton, where the 
bed of. the river itself is one hundred and fifty ewe feet 
above tide-level. Finally, the Philadelphia brick-clay con- 
tains numerous bowlders of considerable size, derived from 
the ledges of Medina sandstone and other rocks above. This 
marks it as a deposit of the glacial flood some time during the 
declining centuries of the great Ice age. 

The succession of events would seem to be as follows: 
During the early part of the Glacial period the ice accumu- 
lated in the upper portion of the valley of the Delaware to a 
depth of many hundred feet. The area in the valley of the 
Delaware covered by the ice is not far from six thousand 
square miles. It is not improbable that the average depth 
of the ice accumulated over the region was considerably more 
than fifteen hundred feet, or a quarter of a mile, making 
the total accumulation of ice more than fifteen hundred 
cubic miles, with its southern border sixty miles above 
Trenton. All this as it melted must find its outlet to the 
sea through the Delaware River. It is evident ata glance 
that during the decline of the Glacial period, when the pro- 
cess of melting was proceeding with greatest rapidity, the 
floods in the valley below must have been upon a scale of 
surprising magnitude. 

And yet it is impossible that diese glacial floods in the 
Delaware should have been so enormous as to have filled the 
valley below Trenton to the height of one hundred and fifty 
feet, for this valley is nowhere less than five miles in width 
and constantly enlarges toward the sea. If the water at 
Trenton were raised one hundred and fifty feet, the slope to 
the bay would be about two feet per mile. Now, a current 
of five miles per hour, one hundred and fifty feet deep and 
one mile wide, would discharge a cubic mile of water every 
eight hours, or three cubic miles per day. (The mean rate 
of the Ohio River, with an average descent of five inches to 
the mile, is three miles per hour—that of the Mississippi 


MAN AND THE GLACIAL PERIOD. 635 


very nearly the same.) To supply such a volume of water 
as this, the whole accumulation of ice in the upper Delaware 
would suflice for only five hundred days, or for about sixteen 
months. And to furnish this amount of water there would 
need to be, during such floods, a daily accumulation by rains 
and the melting ice over the whole upper valley of the Dela- 
ware of about three feet of water, which of course is incred- 
ible, even if we suppose the floods confined to a single month 
of each successive year. Hence, without doubt, we may con- 
clude that the deposition of the bowlder-bearing  brick-clay 
in the Delaware Valley below Trenton implies a depression 
of that region to the extent of one hundred or more feet: 

Doubtless the region north of Trenton shared in this de- 
pression, but, being above the tide-water, the effects would 
not be equally evident. The valley above Trenton is narrow; 
at Lambertville, about twelve miles up the stream, a trap- 
dike contracts the valley to a width of about one quarter 
of a mile. Above this point the supposition of floods suft- 
cient to deposit the bowlder-bearing clay is, therefore, not in- 
eredible, especially since the descent in the stream was prob- 
ably less then than now. For the depression of that period 
proceeded, as we have seen, at increased rate northward. 
In Montreal, it was five hundred feet; in Vermont, about 
three hundred feet; and how much more or less in the 
vicinity of Lake Erie we can not tell. Such depression 
would greatly diminish the velocity of the torrent, and the 
narrow places in the valley would work to the same end. 
Professor Dana has shown that in the lower part of the val- 
ley of the Connecticut River the floods rose during the Cham- 
plain epoch from one hundred and fifty to two hundred feet 
above the present high-water mark. But the Connecticut 
River Valley below Middletown is contracted by trap-dikes 
much as the Delaware is at Lambertville; and the drain- 
age basin of the Connecticut is three times as extensive as 
that of the Delaware (being twenty thousand square miles). 
The effect of this obstruction, however, is partly offset by 
the branch currents which, as Professor Dana shows, set 
off from the Connecticut at various places above Middle- 
town. 


636 THE ICE AGE IN NORTH AMERICA. 


After an exhaustive examination carried on for several 
years in connection with the New Jersey Geological Survey, 
Professor Salisbury reports finding deposits in that state 
corresponding to those here spoken of as Philadelphia brick 
clay and red gravel, which he describes under the local names 
of Bridgeton and Pensauken, reaching a height of 200 feet 
in the case of the former and 150 of the latter. But he is 
inclined to refer these ‘in large part to subaérial (fluvial 
and pluvial origin’). On this theory the deposits were 
chiefly brought into place by the Delaware and its tributaries 
during the close of the first glacial period, when the land was 
nearly at its present level, and the streams were overloaded 
with glacial débris. This accumulated as a broad delta over 
lowlands which were subsequently so much eroded that only 
the present remnants are left. 

But the extent over which the deposit is spread, as well 
as its character militates strongly against this theory. For 
the deposit extends for many miles northeast of the Delaware 
at Trenton, above where the unaided current of the glacial 
stream would carry the material, while several miles south- 
east of Trenton, bowlders, three and four feet in diameter, 
are found at an elevation of 200 feet, the bowlders being 
identical in material with others bearing glacial scratches 
found in the valley of the Delaware, twenty or thirty miles above 
Trenton. It hardly is possible that the whole area south of 
Trenton to the limit of these bowlders was covered with 
Bridgeton gravel to this height, Besides, the distribution 
of the bowlders in the brick clays of Philadelphia was evidently 
by stranded icebergs. In this clay bowlders two and three 
feet in diameter are distributed in a manner that would be 
impossible in any other way. A depression of 200 feet in the 
lower valley of the Delaware, therefore, cannot easily be 
dispensed with. Similar facts lead to the same conclusion 
respecting the depression at the mouth of the Susquehanna 
at the head of Chesapeake Bay, near Havre de Grace. 


MAN AND THE GLACIAL PERIOD. 637 


At any rate, in the Delaware Valley we find bowlder-bear- 
ing clay rising to a height of one hundred and tifty or more 
feet above the present high-water level. In the Lehigh 
Valley, at Bethlehem, a few miles above its junction with 
the Delaware, and several miles south of the limit of the ice- 
field, Professor Lewis and myself found this bowlder-bearing 
clay containing scratched pebbles and lying unconformably 
upon thick deposits of coarse stratified gravel at a height 
of one hundred and eighty feet above the river. Farther 
up the Lehigh Valley also, near Weissport, we ascertained 
the limit of ice-carried bowlders to be one hundred and 
eighty feet above the river. 

We are probably safe in assuming that these floods, de 
positing clay and bowlders at the height above mentioned, 
mark both the period of greatest depression during the Gla- 
cial epoch and that when the ice was most rapidly melting 
away. Of course, the deposition of what Professor Lewis 
styles “red gravel,’ and the high gravels at Bethlehem, oc- 
curred earlier, since the clay overlies them. 

It is evident that the deposition of this bowlder-bearing 
clay is separated from that of the implement bearing gravel 
at Trenton by a period of considerable physical changes, if 
not of vast time. 

Considering, now, this Trenton gravel, we find it to be 
limited at the head of tide-water toa level of about forty 
feet, and diminishing in height relatively to the river both 
as one ascends and as one descends the channel, until at 
Yardleyville, a few miles above Trenton, it merges into the 
terrace which maintains a pretty uniform height of fifteen or 
twenty feet above the river all the way to the Water-Gap. 
Above the Water-Gap the gravel terraces rise to a much 
greater height. At Stroudsburg a second terrace stands 
seventy-five feet above the first terrace, which is about fifteen 
feet above Broadhead Creek. But this upper terrace is 
kame-like in its structure, and hence would be explained in 
part by the lingering presence of the glacier itself. 

The descent of the river-valley from Belvidere, where the 


638 THE ICE AGE IN NORTH AMERICA. 


ice-sheet terminated, to Trenton, is two hundred and thirty- 
two feet, or.at the rate of nearly four feet per mile. 

‘Now, the transportation of gravel by a river is dependent 
both upon the amount of material accessible to the running 
stream and upon the rapidity of the current. Toward the ~ 
close of the Glacial period the pebbles accessible to the stream 
were superabundant, having been deposited in excessive 
amount by the melting of the glacier in the lower latitudes. 
The water-worn pebbles at Trenton were probably largely 
derived from this source. Even a glacial torrent may have 
more loose material than it can manage, and so may silt up 
its bed with gravel. Hence it is not necessary to suppose 
the river at this point to have been of sufficient volume to 
fill the whole valley with water to the height of the terraces, 
tifteen or twenty feet. The river may have flowed upon a 
more elevated gravel bottom in a shallower current = the 
terrace would seem to imply. 

When, now, the current, passing down this declivity of 
four feet to the mile, reached the level of the sea at Trenton, 
its transporting power would be greatly diminished, and thus 
we should have an accumulation of gravel at the head of 
tide-water, without bringing into the problem the supposition 
of any very extraordinary increase in the volume of the 
river. The transporting capacity of a stream of water is esti- 
mated to vary as the sixth power of the velocity; i. e:, if a 
current is checked so that it moves at only half its former 
rate, its transporting capacity is diminished to one sixty- 
fourth.* It is easy to see that the sudden enlargement of 
the valley just above Trenton, as well as the occurrence there 
of tide-water, would diminish the rapidity of the river, and 
hence cause an extraordinary deposition of gravel when 
the moraines above were fresh and when ice-fields still lin- 
gered in the southern valleys of the Catskills. The process 
of deposition must have been so rapid that it might well 
have taken place not long before the withdrawal of the con- 


* See Le Conte’s “ Elements of Geology,” pp. 18-20. 


MAN:AND THE GLACIAL PERIOD. 639 


tinental glacier to the north of the Catskills. The time re- 
quired for the river under present conditions. to erode the 
channel it now occupies was of much greater duration. The 
following is the probable course of events : 

1,,.The Philadelphia brick-clay was deposited during the 
height of the Glacial epoch, when the Delaware Valley was 
considerably depressed below its present level. This is Mc- 
Gee’s Columbia. period. | 

2; Toward the close of that period, when the land had 


‘resumed its present level and the ice had nearly all. dis- 


appeared :south of the Catskills, the still. swollen stream 
brought-down the superabundant loose material from the 
kames:and moraines of. the glaciated area and deposited it in 
the valley below. The material was so abundant that doubt- 
less the whole. channel was silted up so that the bed of the 
river was considerably above. that it now occupies. At Tren- 
ton. it flowed over:and through:an extensive delta of coarse 
‘grayel forty feet above its present level ; and, above Trenton, 
dyer an accumulation of gravel from fifteen to twenty feet 
above the present high-water mark. This period was marked 
by the presence of the mastodon and. other extinct animals 
with: palzeolithic man in the neighborhood of Trenton.* 
« , 8.. During the Terrace epoch the river. worked its way 
‘down. through the delta gravel at Trenton, and has since 
eroded: its present channel which is about two miles wide. at 
that point. Higher up, where the current is swift, the lateral 
erosion in recent times has been small. 

.4, To.determine approximately the date of the earliest 
evidence of man’s appearance at Trenton we have as data: 
(1) The amount of erosion in the gravel at Trenton. (2) The 


¥ Tt should have been mentioned earlier that Professor Cook found in this 
gravel, fourteen feet below the surface, the tusk of a mastodon, and that near 
the same place, at a depth of sixteen feet from the surface, Dr. Abbott took 
from it a portion of a human under-jaw, also from another place a human tooth, 
and from still another’ a “‘ very thick and in several respects singular human 
cranium.” Interesting as these are, however, they are too fragmentary to add 
materially to our information derived from the implements. See ‘‘ Annual Geo- 
logical Report for New Jersey for 1878,” p. 24; “Report of Peabody Museum 
for 1886,”’ p. 408. 


640 THE ICE AGE IN NORTH AMERICA. 


general evidence from other sources bearing upon the date 
of the close of the Glacial epoch in this country, more fully 
treated of in the preceding chapter. 

Since my first visit to Trenton I have studied attentively 
all the streams situated like the Delaware with reference to 
the glaciated area between the Atlantic Ocean and the Mis- 
sissippi River, and can state from personal observation, as 
heretofore detailed, that a common cause, which can not be 
anything else than glacial floods operating while the ice re- 
mained over the head-waters of these streams, has been at 
work filling them with gravel-deposits similar to those de- 
scribed along the Delaware. Without exception, those south- 
erly-flowing streams, whose drainage area lies to any consider- 
able extent within the glaciated regions, are lined by exten- 
sive terraces of the overwash gravel of the Glacial! period. 

On obtaining definite information as to these facts, I at 
once pointed out * the importance of having local observers 
turn their attention to the discovery of palzoliths at various 
points in Ohio, where the glacial conditions were similar to 
those in the valley of the Delaware at Trenton. In my re- 
port to the Western Reserve Historical Society (p. 26) I wrote 
as follows: *“‘The gravel in which they [Dr. Abbott’s im- . 
plements] are found is glacial gravel deposited upon the 
banks of the Delaware when, during the last stages of the 
Glacial period, the river was swollen with vast floods of 
water from the melting ice. Man was on this continent at 
that period when the climate and ice of Greenland extended 
to the mouth of New York Harbor. The probability is, that 
if he was in New Jersey at that time, he was also upon the 
banks of the Ohio, and the extensive terrace and gravel de- 
posits in the southern part of our State should be closely 
scanned by archeologists. When observers become familiar 
with the rude form of these palzolithic implements, they will 


* “ American Journal of Science,” vol. cxxvi, pp. 7-14; “The Glacial 
Boundary in Ohio, Indiana, and Kentucky”; ‘‘ Western Reserve Historical 
Society,” 1884, pp. 26,27; ‘Ohio Archeological and Historical Quarterly,” 
vol. i, pp. 176, 177. 


MAN AND THE GLACIAL PERIOD. 641 


doubtless find them in abundance. But whether we find 
them or not in this State [Ohio], if you admit, as I am com- 
pelled to do, the genuineness of those found by Dr. Abbott, 
our investigation into the glacial phenomena of Ohio must 
have an important archeological significance, for they bear 
upon the question of the chronology of the Glacial period, 
and so upon that of man’s appearance in New Jersey.” 

The substance of these remarks had been previously made 
by me in a meeting of the “Boston Society of Natural His- 
tory ” for March 7, 1883, and reported in “ Science,” vol. i, pp. 
269-271. Commenting upon this report Dr. Abbott sent a 
communication to “ Science,” from which the following ex- 
tracts are very significant and interesting as connected with 
the discussion : 


In ‘‘ Science” of April 13th, p. 271, Professor Wright re- 
marks that ‘‘no paleolithic implements have yet been found 
fin Ohio], but they may be confidently looked for.” It has 
seemed to me possible, from mv own studies of the remains of 
paleolithic man in the valley of the Delaware River, that traces 
of his presence may only be found in those river-valleys which 
lead directly to the Atlantic coast, and that paleolithic man 
was essentially a coast-ranger, and not a dweller in the interior 
of the continent. If we associate these early people with the 
seal and walrus rather than with the reindeer, and consider 
them essentially hunters of these amphibious mammals rather 
than of the latter, it is not incredible, I submit, that they did 
not wander so far inland as Ohio, nor even so far as the east- 
ern slope of the Alleghanies ; and we need not be surprised if 
palzolithic implements, concerning which there can be no 
doubt whatever—for recent Indians made and used stone imple- 
ments that are ‘‘ paleolithic”’ in character—are not found in 
Ohio, nor even in Pennsylvania west of the valley of the Sus- 
quehanna River... . 

On the other hand, if the relationship of paleolithic man 
and the Eskimo is not problematical, and the latter is of Ameri- 
can origin, then I submit that man was preglacial in America, 
was driven southward by the extension of the ice-sheet, and 
probably voluntarily retreated with it to more northern re- 


642 THE ICE AGE IN NORTH AMERICA. 


gions ; and, if so, then in Ohio true palezolithic implements will 
surely be found, and evidences of man’s preglacial age will ulti- 
mately be found in the once-glaciated areas of our continent.* 


The expectation of finding evidence of pregiat man 
in Ohio was met not long after this. 

Ata meeting of the Boston Society of Natural History t 
for November 4, 1885, “ Mr. Putnam showed an implement 
chipped from a pebble of black flint, found by Dr. C. L. 


Fic. 166.—Chipped pebble of black chert, found by Dr. C. L. Metz, October, 1885, at Madi- 
sonville, Ohio, in gravel eight feet from surface under clay, a, face view ; b,'side 
view. Note its resemblance to Fig. 126, from Trenton, New Jersey. (No. 40,970.) 
(Putnam. ) 

Metz, in gravel, eight feet below the surface, in Madison- 

ville, Ohio. This rude implement is about the same size and 

shape of one made of the same material, found by Dr. Ab- 
bott in the Trenton (N. J.) gravel, and is of special interest 
as the first one known from the gravels of Ohio.” Professor 

Putnain’s announcement, followed by a letter from Dr. Metz, 


saying that he had since found another implement in the 


* “Science,” vol. i, p. 359. ¢ “ Proceedings,” vol. xxiii, p. 242. 


MAN AND THE GLACIAL PERIOD. 643 


gravel at Loveland, led me, on the 11th and 12th of No- 
vember, 1887, to visit the localities and see their relation to 
the glacial deposits of the region. The situation is as fol- 
lows: 


! 
t 

id O 
| WARREN 


e 
Lebanon 


a 


AS ae 
KS 76 
RIES 


PRICE rere 


S 
Ss 


eee eer 


Scale of Miles RS a 
RSS 
an ae 8% spl 
J.C. Teaters, B.C.ES/A/ 
7 


RS 
Ly 


pe 


wot ts 


Fic. 167.—Map showing glacial boundary, channels, and terraces near Cincinnati. 


Madisonville is situated eleven miles northeast of Cincin- 
nati, in a singular depression connecting the Little Miami 
River with Mill Creek, about five miles back from the Ohio 
(see Fig. 167). The Little Miami joins the Ohio some miles 
above Cincinnati, while Mill Creek joins it just below the 


644 THE ICE AGE IN NORTH AMERICA. 


city. The general height of the hills in that vicinity above 
the river is from four hundred to five hundred feet. But 
the hills just north of Cincinnati are separated from the 
general elevation farther back by the depression referred to, 
in which Madisonville is situated. — 

The depression is from one to two miles wide, and about 
five miles long, from one stream to the other, and is occu- 
pied by a deposit of gravel, sand, and loam, clearly enough 
belonging to the Glacial-terrace epoch. Recent investigations 
make it probable that the Ohio formerly flowed north through 
Mill Creek, and joined the Great Miami near Hamilton. The 
surface of this is generally level, and is about two hundred 
feet above the low-water mark in the Ohio. On the east 
side, on the Little Miami River, at Red Bank, opposite Madi- 
sonville, the gravel is coarse, merging into pebbles from one 
to three or four inches through, interstratitied with sand, and 
- underlaid, near the river-level, with fine clay. There is here 
a thin covering of loess, or fine loam. On going westward 
this loess-deposit increases in thickness, being at Madison- 
ville, one mile west, about eight feet thick. Farther west 
it is much deeper, and seems to take the place of the gravel 
entirely. At several railroad cuttings, compact glacial clay 
appears underneath all. 

Thus, it is evident that this cross-valley, connecting Mill 
Creek with the Little Miami back of Avondale, Walnut © 
Hills and the observatory, was once much deeper than now, 
and has been filled in with deposits made when immense 
glacial floods were pouring down these two streams from the 
north. The Little Miami was a very important line of glacial 
drainage, as is shown by the extensive gravel-terraces all along 
its course, to which the railroads resort for ballast. The 
coarser material was deposited near the direct line of drainage, 
where the current was strong, while back from the river to- 
ward Madisonville, there was naturally an increase of the fine 
deposit, or loess, which is practically a still-water formation. 

In making an excavation for a cistern, Dr. Metz pene- 
trated the loess, just described, eight feet before reaching 


MAN AND THE GLACIAL PERIOD. , 645 


the gravel, and there, just below the surface of the gravel,. 
the implement referred to was found. There is no chance 
for it to have been covered by any slide, for the plain is ex- 
tensive and level-topped, and, according to Dr. Metz, there 
had evidently been no previous disturbance of the gravel. 

Subsequently, in the spring of 1887, Dr. Metz found 
another paleolith in an excavation in a similar deposit in the 
northeast corner of the county, on the Little Miami across 
from Loveland. The river makes something of an elbow 
here, open to the west. This space is occupied by a gravel- 
terrace about fifty feet above the stream. The terrace is 
composed in places of very coarse material, much resembling 
that of Trenton, N. J.. where Dr. Abbott has found imple- 
ments. The excavation is about one quarter of a mile hack 
from the river, near the residence of Judge Jolmson. The 
section shows much coarser material near the surface than at 
the bottom. The material is largely of the limestones of the 
region, with perhaps ten per cent of granitic pebbles. The 
limestone pebbles are partially rounded, but are mostly ob- 
long. Some of them are from one to three feet in length. 
These abound for the upper twenty feet of the section on 
the east side toward the river. One granitic bowlder noticed 
was about two feet in diameter. On the west side of the 
eut, away from the river, mastodon-bones were found ina 
deposit of sand underlying the coarser gravel and pebbles. 
It was here, about thirty feet below the surface, that Dr. 
Metz found the paleolithic implement referred to. 

In October, 1889, Mr. W. C. Mills, president of a local 
archeological society of some importance at Newcomerstown, 
on the Tuscarawas River, in Ohio (see map on page 168), found 
a flint implement of paleeolithic type fifteen feet below the sur- 
face of the glacial terrace bordering the valley at that place. 
The facts were noted by Mr. Mills in his memorandum-book at 
the time, and the implement was placed with others in his col- 
lection. But, as he was not familiar with implements of that 
type, and did not at the time know the significance of these 
gravel deposits, nothing was said about it until meeting me the 
following spring, when I was led from his account to suspect 


646 THE ICE AGE IN NORTH AMERICA. 


the importance of the discovery. Mr. Mills soon after 
sent the implement to me for examination, and its value 
at once became apparent. In company with Judge C. C. 
Baldwin and two or three other prominent citizens of 
Cleveland, [ immediately visited Newcomerstown. A cut 


Fie. 168.—The smaller is the paleolith from Newcomerstown, the larger from Amiens 
(face view). 


of the implement is given in the accompanying pages, 
made from a photograph one quarter the diameter. Beside 
it is a paleolith which came into my possession from Dr. 
Evan’s collection in London, with his certification that it 
is from the valley of the Somme. The two implements as 
they appear side by side, are in shape and finish the exact 


—— or cS TC 


MAN AND THE GLACIAL PERIOD. 647 


counterparts of each other. The one from Newcomers- 
town, however, is made from a local flint which occurs in 
nodules in the “Lower Mercer” limestone, which is situated 
in the lower part of the coal-measures, and crops out a few 
miles from there. 


ane 


Ub 


Fie. 169.—Edge view of the preceding. 


The implement has upon it the patina characteristic of 
the genuine flint implements of great age in the valley of 
the Somme, and is recognized by Professor Haynes, of 
Boston, as in itself fullfilling all the requirements looked 
for in such a discovery. The gravel-pit in which it was 
found is one which for some years has been resorted to by 


648 THE ICE AGE IN NORTH AMERICA. 


the railroads for ballast. Mr. Mills saw the implement as 
it was projecting from the undisturbed gravel in the fresh 
exposure, and took it out with his own hands. The surface 
of the glacial terrace is here thirty-five feet above the 
prefent high-water mark of the river, and, as already said, 
the implement was found fifteen feet below the surface. 
The terrace is one which characterizes the Tuscarawas 
River everywhere below the glacial boundary, and the 
illustration upon page 324 might well have been taken 
from this very spot. 


Fic. 170.— Face View Fic. 171—Face View. Fic. 172—Diagonal View 
of the Implement of Sharpened Edge. 


In 1892 another important discovery was made in the upper 
terrace of the Ohio River at Brilliant, Ohio. This was a well 
fashioned flint implement one inch long which was found in 
place beneath eight feet of cross bedded sand and gravel where 
there had been no chance for secondary deposition or a land 
slip. The surface of the terrace was nearly uniform for two 
miles in length and a quarter of a mile in width at a height 
of 80 feet above low water, and fifty feet above the present 
high water mark. Excavations near by to a depth of 43 feet 
show continuous cross bedded stratification of sand and gravel 
with clay in small quantities. Mr. Sam Huston, the County 
Surveyor, and a well known geological collector of highest 


MAN AND THE GLACIAL PERIOD. 649 


reputation saw the point of the implement projecting from 
the perpendicular bank while the workmen were at dinner, 
and extracted it with his own hands. The implement was 
submitted to the joint meeting of the Geological and Anthro- 
pological sections of the American Association for the Ad- 
vancement of Science at Springfield Mass., in 1895, where 
Professor F. W. Putnam, Mr. F. H. Cushing and Miss Alice 
Fletcher and others all recognized it as an indubitable relic 
of great antiquity. 

Its great age was indicated by the patina with which it 
was covered, and by the fact, instantly recognized by Dr. 
Cushing, that the form was antique, being intermediate 
between that of paleoliths and modern Indian implements. 


Fie. 173.—Section of the Trough of the Ohio at Brilliant. Location of 
the implement shown by a *. 


For full accounts see ‘‘Popular Science Monthly” for De- 
cember 1895, pp. 157-166. 

The cumulative evidence of these facts is increased with 
the discovery, by Mr. Hilborne T. Cresson, of Philadelphia, 
in 1886, of implements of similar type in Medora, Ind. 
Medora is situated in Jackson county, about one hundred 
miles west of Cincinnati, and is on the border of the glaciated 
region in that State. The situation is upon the East Fork of 
White River, near where it enters the triangular unglaciated 
portion of Southern Indiana as seen in the map of the gla- 
cial boundary. The eastern border of this consists of sand- 


duet tS 


Raa 
NS 


Xx 


SS 
No 


as ! 


at tata 
1 


> 
“os 


. a 
x 
ore 


ke 


aS 


SS 


a 


ee 


ix 


wes 
3 


meESS 
» 7“. % 
7] 


ry 
aS ae we 


SARE) 


Fie. 174,— Paleolith of gray flint, found by Mr. H. T. Cresson, May 1886, at Medora, In- 
diana, in glacial gravel, eleven feet from surface, in bluff on east fork of White River. 
(Face view.) (No. 46,145.) (Putnam.) 


Fic. 175.—Side view of the preceding. (Putnam.} 


652 THE ICE AGE IN NORTH AMERICA 


stone knobs formed by the outcropping of the subearbonit- 
erous strata, which here dip to the west. The unglaciated 
area is, therefore, considerably higher than that which adjoins 
it on the east, and is much cut up into gorges along the 
drainage lines, and must have furnished a favorite retreat, 
both for man and animals, during the maximum extension of 
the ice. . 

Mr. Cresson, having been called into this locality on busi- 
ness, and finding that it was near the glacial boundary as I 
had recently traced it, was led to turn aside for an hour or 
two to examine a bank of modified drift. While digging 
with his hunter’s knife under a bowlder of about one hun- 
dred pounds weight to see if it showed signs of glaciation, he, 
to his surprise encountered a well-wrought paleeolithie flint 
implement. Fortunately, a long experience in exploring the 
gravel-beds in France where paleoliths occur (and, indeed 
from experience in exploring while a youth a shelter-cave 
which we will hereafter describe, on the banks of the Dela- 
ware) had prepared him fully to appreciate the discovery ; 


Fic. 176.—Section of glacial gravel at Medora, Indiana. in which Mr. Cresson found the 
palreolith figured in the text. A. is a deposit of soil three feet in depth ; B, modified 
drift eight feet in depth: D. is probably till ; L, L, layers of alluvium ; C, the bowl- 
der, under which the implement was found at X. 


and he remained a day or two until he had thoroughly in- 
vestigated the surroundings and made further search for im- 
plements. Such search, however, was not rewarded with suc- 
cess, since all that he found later were from the surface, and 
of a neolithic type. According to Mr. Cresson, this palzeo- 


MAN AND THE GLACIAL PERIOD, 653 


lith was found in undisturbed gravel about fifty feet above 
the flood-plain of the river. The gravel was firmly packed, 
and the implement was with difficulty extricated from it with 
his hunting-knife. Above it and the bowider just mentioned 
were eight feet of gravel and loam, capped by three feet of soil. 
Mr. Cresson was thoroughly convinced that it would have 
been impossible for any implement of recent manufacture to 
have rolled down from the soil above and assume the position 
it was in with reference to the bowlder. Besides, the imple- 
ment is of a true palzolithic type, and has the usual marks 
of age characterizing such implements.* 


Th 

Hm oe 

é es ae 
\ i 


1 
AN 


Fic. 177.1, a, convex surface of a chert implement found at the month of Little Elk 
River. Morrison County, Minnesota, sapposed to be a scraper. 1.0. profile view of the 
same.t 2, @, convex surface of « chert implement found at Little Falls. Minnesota. 
2, 6. profile view of the same. The figures do not perfectly represent the evident- 
ly chipped edges. (Winchell.) 

Another locality especially worthy of attention, in which 
palzoliths have been found, is at Little Falls. Morrison 
county, Minnesota, the situation of which ean readily be seen 
by reference to the map on page 546. The first discover- 
ies at this point were made as long ago as 1877, and an ac- 
count of them was given in the “Sixth Annual Geological 
Report of Minnesota.” + These implements were made from 


chert and quartz, and were recognized by Professor N. H. 


* See Mr. Cresson’s report on the subject, in the “ Proceedings of the Boston — 
Society of Natural History,” vol. xxiv, p. 150 et seq. 
+ This specimen is regarded a finished inplement by Putnam.  { Pp. 53-58. 


654 THE [CE AGE IN NORTH AMERICA. 


Winchell as belonging to the age of the glacial deposits 
which here line the trough of the Mississippi. A little later, 
Miss France E. Babbitt examined the locality more carefully, 
and found a large number of additional implements. 
Her discoveries were first reported in a paper read before 
the Minnesota Historical Society in February, 1880. A 
fuller account was presented at the meeting of the Ameri- 
can Association for the Advancement of Science at Minne- 
apolis in August, 1883. At that time also the subject was 
thoroughly canvassed by the numerous geologists present, 
and a paper was read upon the subject by Mr. Warren 
Upham, to whose work upon the surface geology of the 
Northwest we have so often had occasion to refer. To get 
the whole subject before our readers we can do no better 
than to append the principal portion of an elaborate paper 
read by Mr. Upham before the Boston Society of Natural 
History, on December 31, 1887, which will be the more 
readily understood by reason of the previous chapters of the 
present volume detailing the general results of Mr. Upham’s 
work in that region : 


The recession of the ice-sheet of the last Glacial epoch in 
Minnesota seems to be clearly marked by as many as ten 
stages of halt or readvance, in which distinct marginal mo- 
raines were accumulated, besides the moraine on the limits 
of its farthest extent. Six summers of geologic field-work 
in that State have been spent by the writer chiefly in the 
examination of its glacial and modified drift, of these mo- 
raines, and of the beaches and deltas of the glacial Lake 
Agassiz, which was formed in the valley of the Red River of 


the North and of Lake Winnipeg by the barrier of the 


departing ice-sheet. In their bearings upon this subject, my 
observation and study of that region convince me that the 
rude implements and fragments of quartz discovered at Little 
Falls were overspread by the glacial flood-plain of the Mis- 
sissippi River. while most of the northern half of Minnesota 
was still covered by the ice, contemporaneously with its for- 
mation of the massive moraines of the Leaf Hills and with 


MAN AND THE GLACIAL PERIOD. 655 


the expansion of Lake Agassiz on their west side, respectively 
sixty and eighty-five miles west of Little Falls. This was 
during the highest stage of Lake Agassiz, and previous to its 
extension beyond the north line of Minnesota and Dakota. 
More than twenty lower beaches of this glacial lake have been 
traced, belonging to later stages in the recession of the ice- 
sheet, before it was melted so far as to reduce Lake Agassiz 
to its present representative, Lake Winnipeg. Estimated by 
comparison with the series of moraines and beaches formed 
during the glacial recession, the date of the gravel plain at 
Little Falls appears to be about midway between the time of 
maximum extent of the last ice-sheet and the time of its 
melting on the district across which the Nelson River flows 
to Hudson Bay. | 

The town of Little Falls is on the east bank of the Mis- 
sissippl River, in Morrison county, near the geographic center 
of Minnesota. It is about a hundred miles northwest from 
St. Paul and Minneapolis, and nearly an equal distance 
southeast from Itasca Lake. The elevation of Itasca Lake 
is about 1,450 feet above the sea; of the Mississippi, at the 
head of the rapids or Little Falls, from which the town derives 
its name, 1,090 feet ; and at the head of St. Anthony’s Falls 
in Minneapolis, 796 feet. Following the general course of 
the river, without regarding its minor bends, its descent from 
Lake Itasca by Little Falls to Minneapolis averages about two 
feet per mile, and is approximately uniform along the entire 
distance. Considered in a broad view, this central part of the 
State may be described as a low plateau, elevated a few hundred 
feet above Lake Superior on the east and the Red River Valley 
on the west., In most portions it is only slightly undulating 
or rolling, but these smooth tracts alternate with belts of 
knolly and hilly drift, the recessional moraines of the ice- 
sheet, which commonly rise fifty to one hundred feet, and in 
the Leaf Hills one hundred to three hundred and fifty feet 
above the adjoining country. The bed-rocks are nearly every- 
where concealed by the drift-deposits, into which the streams 
have not eroded deep valleys, their work of this kind being 
mostly limited to the removal of part of their glacial flood- 
plains. The upper portions of the Mississippi and of its 


656 THE ICE AGH IN NORTH AMERICA. 


chief tributaries, and all the smaller streams throughout this 


region, flow in many places through lakes which they have. 


not yet filled with silt nor drained by cutting down their 
outlets. At Little Falls the glacial flood-plain of the Mis- 
sissippi is about three miles wide, reaching two miles east, 
and one mile west from the river. Its elevation is twenty- 


five to thirty feet above the river at the head of the rapids, 


which have a descent of seven feet. The Mississippi here 
flows over an outcrop of Huronian slate, and the same forma- 
tion is also exposed by the Little Elk River near its mouth, 
on the west side of the Mississippi three miles north of Little 
Falls. Veins of white quartz occur in the slate at both these 
localities, and were doubtless the source of that used by man 
here in the Glacial period for the manufacture of his quartz 
implements. | 

The locality and section of the modified drift, where these 
worked fragments of quartz were found by Miss Babbitt, 
and the account of their discovery, are best told in her own 
words from her paper read before the Anthropological Section 
of the American Association for the Advancement of Science 
at its Minneapolis meeting in 1883. I quote as follows : 

‘‘Rudely worked quartzes had previously been discovered 
here by the State Geologist of Minnesota, Professor N. H. 
Winchell, by whom they had been described and figured in 
the State Geological Report for 1877. . . . The find reported 
by Professor Winchell consists of chipped objects of a class 
generally ascribed to what is called the rude stone age. Of 
these many appear to be mere refuse, while others are regarded 
as finished and unfinished implements. The Winchell speci- 
mens have been assigned, upon geological ground, to a pre- 
historic era antedating that of the mound-building races, and 
reaching back to a time when the drift material of the terrace- 
plain was just receiving its final superficial deposit. It is 
found that, at intervals, the surface soil of the terrace con- 
tains these quartzes to a depth of not unfrequently three or 
four feet. | 

“The lowest and newest formation at this place is the 
present flood-plain of the river. It is still in process of depo- 
sition, being yet subject to partial overflows at periods of 


y 
ae =~ 
— 
sa ed ek ial emcee ral" Fees 


MAN AND THE GLACIAL PERIOD. 657 


exceptionally high water. In that portion of the town of 
Little Falls situated east of the Mississippi, this bottom-land 
is limited on the east by a high, ancient river-terrace, which 
has here an average elevation of about twenty-five feet above 
the river. . . . This older terrace, like the present flood-plain, 
has been spread out by the immediate action of water. . ... 


Fic. 178.—Quartz implement, found by Miss F. E. Babbitt, 1878, at Little Falls. Minneso- 
ta, in modified drift, fifteen feet below surface. a, face view; 0, profile view. The 
bdlaek represented on the cut is the matrix of the quartz vein. (No. 31,323.) (Put- 
nam.) 


While occupied in examining the river bank at Little Falls in 
quest of wrought quartzes, one day during the season of 1879, I 
had occasion to ascend a slope lying between the new flood-plain 
and the older terrace, by a path leading through a sort of gap 
or notch in the latter (three hundred and ten rods, very nearly, 
or almost one mile north of the east-west road by Vasaly’s 
Hotel ; ten rods west of the road to Belle Prairie ; and thirty- 
eight rods from the river). . . . It seemed that at some past 
period a cut had been effected here by drainage, and that the 
wash-out thus formed had afterward been deepened by being 


658 THE ICE AGE IN NORTH AMERICA. 


used, now and then, as a wagon-track. In this notch I dis- 
covered the soil to be thickly strewed with pieces of sharp, 
opaque quartz. These were commonly of a white color, and 
ranged in size from minute fragments to bits as large as a 
man’s hand, and in some instances even larger. There were - 
many hundreds of these chips visible, scattered over an area 


Fic. 179—Quartz implement. found by Miss F. E. Babbitt, 1878, at Little Falls, Minne- 
sota, in modified drift, fifteen feet below surface. a, face view ; 5, side view. (No. 
31,316.) (Putnam.) 


the width of the wagon road, and ten or fifteen yards im length. 
They were conspicuously unwaterworn, and likewise mostly 
unweathered, though occasionally a bit was picked up having 
some one of its surfaces weathered, while fractured or wrought 
faces appearing upon other parts of it, looked as fresh as if the 
work of yesterday. On the other hand, the mass of stone 
rubbish upon and among which the quartzes were strewed is 
much water-worn, many of the pieces being well rounded, while. 
none of them are wholly angular. 

‘* By continued observations at this locality, I found that 
many of these quartz chips were brought to light at every suc- 
ceeding freshet of the season, being washed out of the sand by 


MAN AND THE GLACIAL PERIOD. 659 


descending drainage. Their immense and continually increas- 
ing numbers seemed to warrant the belief that they had re- 
sulted from systematic operations of some sort, once conducted, 
for unknown purposes, upon this particular spot. A portion 
of the studied specimens subsequently yielded evidence of 
having received shape from human hands, and therefore it 
was assumed provisionally that the site of exposure represented 
a prehistoric workshop. 

“* Prolonged investigation ensued ; and investigation estab- 
lished the hitherto unsuspected fact that no quartz chips nor 
fragments were inclosed in the upper part of the gravel and 
sand terrace at the notch, nor within a considerable distance 
at either hand, though they were sought with careful scrutiny. 
. . . Ultimately it was ascertained that the notch quartzes had 
dropped to the level at which they were seen from a thin layer 
of them once lying from ten inches to two feet above it, and 
subsequently broken up through the wearing away of the sand 
underneath by drainage. This layer or stratum was still intact 
on the north and south and partially so on the east, in which 
direction it had, however, at certain points, suffered some dis- 
placement by wagoning. It extended in a nearly horizontal 
plane into the terrace, in the sloping edge of which the notch, 
opening into its west bank and truncated at its edge, is cut. 
. . . The quartz-bearing layer averaged a few inches only in 
thickness, varying a little as the included pieces happened to 
be of smaller or larger size. The contents were commonly 
closely compacted, so much so that one might sometimes ex- 
tract hundreds of fragments, many of them very small ones, 
of course, from an area of considerably less than a square yard. 

“The quartz bed, so far as examined, rested upon a few 
inches of sandy soil, which passed downward into a coarse 
water-worn gravel, immediately overlying till. Above the 
quartz chips, stratified gravel and sand extended up to the sur- 
face of the terrace. The pebbles of the gravel lying directly 
on the quartz-bearing stratum were small and well rounded, 
and were noticeably less angular than those of the gravel below. 
The stratum of quartz chips lay at a level some twelve or fif- 
teen feet lower than the plane of the terrace-top. 

‘* These observations show that the quartz chips were spread 


660 THE ICE AGE IN NORTH AMERICA. 


originally upon an ancient surface that has been since covered 
deeply by the modified drift which forms the terrace. It will 
be remembered that the quartz chips and implements discovered 
by Professor Winchell in this vicinity are contained in the up- 
per stratum of the terrace-plain ; but the notch quartzes do 
not occur at the terrace-top, and can not have been derived 
from it, but are confined strictly to a single stratum of the 
lower gravels closely overlying the till. Hence the two sets of 
objects can not be synchronous, though they may have been 
produced by the same race at different stages of its existence. 
The notch quartzes must, of course, be older than those de- 
scribed. by Professor Winchell, by at least the lapse of time 
required for the deposition of the twelve or fifteen feet of modi- 
fied drift forming the upper part of the terrace-plain, above 
the quartz-bearing, stratum.” 

This description by Miss Babbitt shows that these imple- 
ments and fragments of chipped quartz occurred in a well-de- 
fined thin layer in the modified drift forming the glacial flood- 
plain of the Mississippi River, as shown in the section which I 
have drawn (see the following figure). I have examined the 


w. Stratum containing dified Dri Ja E. 
ie 4 Caste che pene Terrace of Moc Legied Drif' 1 a aes 
ow epooenas = == = 


terraces and plains of this valley drift from St. Paul and Min- 
neapolis to Brainerd, some twenty-five miles north of Little 
Falls, and find them similar in material and origin with the 
modified drift terraces in the valleys of the Merrimack, Con- 
necticut, and other rivers in New England. These water- 
courses extending southward from the region that was covered 
by the ice-sheet became the avenues of drainage from it during 
its retreat. A part of the drift which had been contained in 
the lower portion of the ice was then washed away by the 
streams formed on the ice in its rapid melting and was depos- 
ited as modified drift, forming layers of gravel, sand, and fine 
silt, in the valleys along which the floods supplied by this 
melting descended toward the ocean. Along the Mississippi 


a ice cael la Ne = a 


a ai = <a iti oe ee eee 


MAN AND THE GLACIAL PERIOD. 661 


the flood-plain of modified drift at Brainerd has a height of 
about 60 feet above the river ; at Little Falls, as before noted, 
its height is 25 to 30 feet; at St. Cloud, 60 feet; at Clear- 
water and Monticello, 70 to 80 feet ; at Dayton, 45 feet ; and 
at Minneapolis, 25 to 30 feet above the river at the head of 
St. Anthony’s Falls. 

The modified drift at Little Falls lies on the till or direct 
deposit of the ice-sheet, and forms a surface over which the 
ice never readvanced. It lies far within the area that was ice- 
covered in the second and latest principal epoch of glaciation, 
and by reviewing the steps in the recession of the ice of that 
epoch we shall be able to ascertain approximately what were 
the outlines of its receding margin when the gravel and sand 
plain of Little Falls was deposited, inclosing these evidences 
of man’s presence. ‘The ice-sheet, supplying both this modi- 
fied drift and the floods by which it was brought, still covered 
much of the upper part of the Mississippi basin, which only 
reaches about a hundred miles north of Little Falls; and: the 
courses of massive morainic belts show the continuation of the 
glacial boundary northwestward across Dakota and with less 
clearness eastward across the Laurentian lakes. 

When the ‘latest North American ice-sheet attained its 
greatest area, its southern portion from Lake Erie to Dakota 
consisted of vast lobes, one of which reached from central and 
western Minnesota south to central Iowa. This lobe in its 
maximum extent ended near Des Moines, and its margin was 
marked by the Altamont moraine, the first and outermost in 
the series of eleven distinct marginal moraines of this epoch 
which are recognizable in Minnesota. When the second or 
Gary moraine was formed, it terminated on the south at Min- 
eral Ridge in Boone county, Iowa. At the time of the third 
or Antelope moraine, it had farther retreated to Forest City 
and Pilot Mound in Hancock county, Iowa. The fourth or 
Kiester moraine was formed when the southern extremity of 
the ice-lobe had retreated across the south line of Minnesota 
and halted a few miles from it in Freeborn and Faribault 
counties. The fifth or Elysian moraine, crossing southern Le 
Sueur county, Minnesota, marks the next halting-place of the 
ice. At the time of formation of the fifth moraine, the south 


662 THE ICE AGE IN NORTH AMERICA. 


end of the ice-lobe had been melted back a hundred and eighty 
miles from its farthest extent, and its southwest side, which at 
first rested on the crest of the Coteau des Prairies, had retired 


‘pease tiled tor oe < 


4 
thirty to fifty miles to the east side of Big Stone Lake and the | 
east part of Yellow Medicine county. During its next stage of 5 
retreat this ice-lobe was melted away from the whole of Le . 
Sueur county, and its southeast extremity was withdrawn to j 
Waconia, in Carver county, where it again halted forming its 4 
1 
; 
| 
R 
. 
‘a 


J 


oe OF 
& MINNESOTA. 
ES) Medified Drift along the Mis S189 pL 


A Glacial Strie. 
7 rminal Moraines. 


Prolable Border of the Ice-sheet at the 
at i time of deposition of the Modified |, 
MNT PAULL Drift at Little Falls. 
Sa) KH Boundary of Lake A TZ 
ema, TS) River Warren. 

GZ Pare of the Driftless Area. 


- 


a ee 


Fic. 181.—Map showing the stages of recession of the ice in Minnesota as described in 
the text. (Upham.) 


sixth or Waconia moraine. The seventh or Dovre moraine 
marks a pause in its recession when its southeast end rested on 


ee ee Te ee en 


MAN AND THE GLACIAL PERIOD. 663 


Kandiyohi county. Probably nearly all of the southern half of 
Minnesota was at this time divested of its ice-mantle, while 
nearly all of the northern half was still ice-covered, the glacial 
boundary across the State passing in an approximately east to 
west course not far from Little Falls. 

By its next recessions the ice-border was withdrawn to the 
eighth or Fergus Falls moraine, and the ninth or Leaf Hills 
moraine. These are merged together in the prominent accnu- 
mulations of the Leaf Hills, which reach in a semicircle from 
Fergus Falls to the southeast, east, and northeast, a distance 
of fifty miles, marking the southern limits of this ice-lobe when 
it terminated nearly due west of Little Falls and half-way be- 
tween the south and north borders of Minnesota. Conspicuous 
morainic hills a few miles east of Little Falls, and others in 
the north part of Morrison county and along its west side, 
seem to be correlated with the Fergus Falls moraine. Much 
of the modified drift of the Mississippi Valley at Little Falls 
was probably deposited when the ice-sheet terminated at these 
hills five to fifteen miles distant on the east, north, and west. 
Eastward from Morrison county, this moraine continues north- 
east to the north side of Mille Lacs, thence probably through 
the south edge of Aitkin county and the north part of Pine 
county, and onward northeasterly to the west end of Lake 
Superior. The Leaf Hills moraine extends from the northeast 
part of the Leaf Hills, near the Leaf Lakes, east across northern 
Todd county and northwestern Morrison county and then 
north-northeast by Gull, Pelican, White Fish, and Crooked 
Lakes. Next it probably takes an eastward course, crossing 
the Mississippi several miles north of Sandy Lake and the 
St. Louis River near the mouth of the Cloquet, and thence 
_an east-northeast course passing not far south of the Cloquet 
River and reaching the north shore of Lake Superior about 
half-way between Duluth and Pigeon Point. The upper portion 
of the modified drift at Little Falls, probably including the 
stratum of chipped fragments of quartz, is referable to the 
time of the recession of the ice-sheet north from the Fergus 
Falls moraine to the Leaf Hills moraine. At the west end of 
the Leaf Hills and thence through a distance of fifty miles 
northward, this stage of recession carried the ice-border 


664 THE ICH AGE IN NORTH AMERICA. 


back only five to ten miles; and in the main Leaf Hills, as 
before noted, the two moraines are united. Across the Mis- 
sissippi basin the glacial recession between them uncovered 
an area mainly twenty to forty miles wide. ‘The portion of 
the ice-sheet nearest to Little Falls at the time of the Leaf 
Hills moraine was in the vicinity of Fish-Trap Lake and Lake 
Alexander, in northwestern Morrison county, only twenty 
miles distant. There, as in the Leaf Hills, this moraine and 
that of Fergus Falls come together. Ascending the Mississippi, 
a distance of eighty miles intervened between Little Falls and 
the ice-border at the time of the Leaf Hills moraine, which 
extends approximately parallel with the river and ten to twenty 
miles from it on its northwest side in passing north-northeast- 
ward from Morrison county. 

During the formation of the tenth or Itasca moraine, and 
of the eleventh or Mesabi moraine, crossing the lake region at 
the head of the Mississippi, the gravel and sand of the modi- 
fied drift were probably wholly deposited north of Little Falls. 
_ Later moraines, formed at times of halt or readvance, inter- 
rupting the recession of the ice-sheet between northern Minne- 
sota and Hudson Bay, have not been determined, but I believe 
that they:exist and await discovery when the glacial drift of 
that wooded and very scantily inhabited region shall be fully 
explored. The many beaches of Lake Agassiz, all showing an 
ascent northward when compared with the level of the present 
time, but with this ascent gradually decreased during the suc- 
cessive stages of the lake, probably find their explanation in 
the manner of retreat of the ice in Canada, interrupted there, 
as farther south, by pauses and the formation of moraines. 

Contemporaneously with the deposition of the glacial flood- 
plain at Little Falls and the accumulation of the Leaf Hills, 
the ice-front forming the north shore of Lake Agassiz crossed 
the Red River Valley between Fargo and Grand Forks, and ex- 
tending northwesterly across northern Dakota, as shown by 
its moraines remarkably developed along the south side of 
Devil’s Lake and onward to Turtle Mountain. Toward the 
east, the ice-sheet at this time had receded from the south- 
west part of Lake Superior, which was held about five hundred 
feet higher than now and overflowed to the St. Croix and 


MAN AND THE GLACIAL PERIOD. 665 


‘Mississippi Rivers by the way of the Bois Brulé River and Upper 

St. Croix Lake. It seems nearly certain also that the ice- 
border continued across Green Bay and the north part of Lake 
Michigan ; and farther east I think that it probably crossed 
southwestern Ontario and the central or northern portions of 
New York, Vermont, New Hampshire, and Maine. The Lau- 
rentian lakes were dammed by the retreating glacial barrier 
and overflowed at the lowest points on their southern water- 
shed. The time when the Little Falls stone implements and 
fragments from their manufacture were covered by the modi- 
fied drift seems therefore somewhat later than that of the im- 
plements found in southern Ohio and in New Jersey ; for, if 
this was the course of the ice-boundary east from the Leaf. 
Hills of Minnesota, it had already receded beyond the region 
where the glacial floods could be discharged by the Little 
Miami and Delaware Rivers. j 

If the question be asked, How many thousand years ago was 
this ? a reply is furnished by the computation of Professor N. 
H. Winchell, that approximately eight thousand years have 
elapsed during the erosion of the post-glacial gorge of the 
Mississippi from Fort Snelling to the Falls of St. Anthony ; 
of Dr. Andrews, that the erosion of the shores of Lake Michi- 
gan, and the resulting accumulation of dune-sand drifted to 
the southern end of that lake, can not have occupied more than 
seventy-five hundred years ; of Professor Wright, that streams 
tributary to Lake Erie have taken a similar length of time to 
cut their valleys and the gorges below their waterfalls ; and of 
Mr. Gilbert, that the gorge below Niagara Falls has required 
only seven thousand years or less. These measures of time 
carry us back to the date of the Little Falls quartz-workers, 
when the ice-sheet of the last Glacial epoch was melting away 
from the basins of the upper Mississippi and of the Laurentian 
lakes. 

Plants and animals doubtless followed close upon the retir- 
ing ice-border, and men living in the region southward would 
make journeys of exploration to that limit, but probably they 
would not take up their abode for all the year so near to the 
ice as Little Falls at the time of the Fergus Falls and Leaf 
Hills moraines. It may be that the chief cause leading men 


666 THE ICE AGE IN NORTH AMERICA. 


to occupy this locality, so soon after it was uncovered from the 
ice, was their discovery of the quartz-veins in the slate there 
and on the Little Elk River, affording suitable material for 
making sharp-edged stone implements of the best quality. 
Quartz-veins are absent or very rare and unsuited for this use 
in all the rock-outcrops of the south half of Minnesota that 
had become uncovered from the ice, as well as of the whole 
Mississippi basin southward, and this was the first spot acces- 
sible whence quartz for implement-making could be obtained. 
While the deposition of the valley-drift at Little Falls was still 
going forward, men resorted there, and left, as the remnants 
of their manufacture of stone implements, multitudes of quartz 
fragments. By the continued deposition of the modified drift, 
lifting the river upon the surface of its glacial flood-plain, 
these quartz-chips were deeply buried in that formation. The 
date of this valley-drift must be that of the retreat of the ice 
of the last Glacial epoch, from whose melting were supplied — 
both this sediment and the floods by which it was brought. 
The glacial flood-plain, beneath whose surface the quartz frag- 
ments occur, was deposited in the same manner as additions 
are now made to the surface of the bottom-land ; and the 
flooded condition of the river, by which this was done, was 
doubtless maintained through all the warm portion of the year, 
while the ice-sheet was being melted away upon the region of 
its head-waters. But in spring, autumn, and winter, or, in 
exceptional years, through much of the summer, it seems prob- 
able that the river was confined to a channel, being of insuffi- 
cient volume to cover its flood-plain. At such time this plain 
was the site of human habitations and industry. After the 
complete disappearance of the ice from the basin of the upper 
Mississippi, the supply of both water and sediment was so 
diminished that the river, from that time till now, has been 
occupied more in erosion than in deposition, and has cut its 
channel far below the level at which it then flowed, excavating 
and carrying to the Gulf of Mexico a great part of its glacial 
flood-plain, the remnants of which are seen as high terraces or 
plains upon each side of the river. 

The question concerning the manner in which human 
remains have become incorporated in the glacial gravels is 


® 


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[op Suljepnumoos y—ze T “pry 


668 THE ICE AGE IN NORTH AMERICA. 


of considerable importance as well as interest. Many have 
seemed to assume that they could come into position only 
by being dropped into the water from a boat. Theaccompany- 
ing illustration, however, from a photograph of Professor 
Russell taken in front of the Malaspina Glacier, Alaska, 
shows what was doubtless the real method. A glacial delta 
is here seen in process of formation. In the summer time, 
when the drainage channels were overcharged both with 
water and débris they would build up a delta terrace near 
their mouth. During a considerable portion of the year, 
however, these deposits would be exposed surfaces over 
which man: could wander and hunt at his leisure. In the 
illustration such a stream has been diverted into a forest and 
is fast burying the trees, as is seen to have been the case in 
front. of the Muir Glacier (see frontis plate). At Trenton, 
N ew, Jersey; this exposed delta terrace would have been 
doubly attractive to man from the fact that it contained. 
many pebbles of argillite from which he was accustomed to 
manufactute his injplements. 


CHAPTER XXII. 
MAN AND THE GLACIAL PERIOD (continued). 


Tue preceding instances all belong, without question, to 
the later stages of the.Ice age in America. Those geologists 
who speak of two glacial periods would classify the gravels 
at Trenton, N. J., Madisonville and Loveland, O., Medora, 
Ind., and Little Falls Minn., as belonging to the later stages 
of the second Glacial epoch—the deposits at Little Falls 
being, as Mr. Upham has already stated, somewhat subse- 
quent to any of the others. We come now to astill more 
startling discovery, made by Mr. Cresson, near his summer 
residence, on the Delaware River,:at Claymont, Del. Fora 
general idea of the situation the reader is referred to the 
map of New Jersey in the general chapter upon the glaciated 
area.* The discovery was made while an extensive excava- 
tion was in progress connected with the building of the Balti- 
more and Ohio Railway. It was my privilege, in November 
1888, to examine the locality in company with Mr. Cresson,, 
Ret bore give the results of the observations : 

The point is located about one mile and a half west of 
the river bank, and about one hundred and fifty feet above 
tide-water. ‘The ascent from the river at Claymont is by three 
or four well-marked benches. These probably are not ter- 
races, in the strict sense of the word, but shelves marking dif- 
ferent periods of erosion, when the land stood at these sev- 
eral levels, but now thinly covered with old river deposits. 
The cut where the discovery was,made is well shown in our 


* See p. 141. 


ee my 
¢ = : 


Cuosseip 4q ydeasojoqd wo) “3x94 043 ut 
pansy sinomtadu srqitjowed punoy uossarD “ay, a9 ‘aIBMRI[ACT “JNOUTARIO IvaT {Nd OIYO PUY sIOTUNTV| JO WOTO9S JO MOTA [RIIUAEH—‘egT “PI 


MAN AND THE GLACIAL PERIOD. 671 


accompanying illustration, reproduced from a photograph. 
The lower part of this cut consists of decomposed schist 
rocks in place and of deposits which are preglacial. These 
extend in the illustration to the top of the light band run- 
ning through the picture. The portion above this light band 
belongs to what was described in the preceding chapter as 
pertaining to the formation denominated by Professor Lewis 
the Philadelphia red gravel and brick-clay, being identical 
with that at Philadelphia both in its composition and in its 
stratigraphical relations, and extending continuously down 
the river from that city (nineteen miles). By Mr. McGee this 
would be denominated the Columbia formation, since he cor- 
relates the deposits in the Delaware Valley with those in the 
District of Columbia in the valley of the Potomac. The age 
of this deposit we have already discussed,* and we need here 
only repeat that it is without doubt a glacial formation of a 
much earlier period than that farther up the valley at Tren- 
ton, N. J., where Dr. Abbott made his important discoveries. 
While that at Trenton belongs to the later stages of the Ice 
age, this at Claymont is to be connected with the ice when 
at its maximum extension, and when the level of the region 
was depressed one hundred feet or more. In a preceding 
chapter I have given.my reasons for questioning the theory 
of Mr. McGee, who would connect this deposit with a glacial 
age previous to, and entirely distinct from, that which was 
concerned with the deposits at Trenton, and which he would 
make from three to ten times as remote. But, whichever view 
upon this point prevails, whether that of two distinct glacial 
epochs, or of one prolonged epoch with various halts in the 
retreat of the ice, the Philadelphia red gravel and brick-clay 
must be regarded on the least calculation as some thousands 
of years older than the deposits at Trenton, N. J., Loveland 
and Madisonville, O., Medora, Ind., and Little Falls, Minn. 

The circumstances of the discovery are thus reported by 
Mr. Cresson : 


* See pp. 613, 635 et seq. 


ee ee ee 


- Kin 


apn ngs 


foam 
a 


a 


ia 


ee eed 


ee ee eee a ee ee 


ee eee eee 


4 

§ 

a 

- 

3 

‘ ‘ 
Fic. 184,—Nearer view of the same, with the finger pointing to the precise place in the 44 
bank where the implement was found. (From photograph by Cresson.) 4 

uy 

) 


MAN AND THE GLACIAL PERIOD. 673 


Toward midday of July 13, 1887, while lying upon the 
edge of the railroad cut, sketching the bowlder line, my eye 
chanced to notice a piece of steel-gray substance strongly re- 
lieved in the sunlight against the red-colored gravel just above 
where it joined the lower grayish-red portion. It seemed to 
me like argillite, and, being firmly imbedded in the gravel, was 
decidedly interesting. Descending the steep bank as rapidly 
as possible, the specimen was secured. . . . Upon examining 
my specimen, I found that it was unquestionably a chipped 
impiement. There is no doubt about its being firmly imbed- 
ded in the gravel, for the delay I made in extricating it with 
my pocket-knife nearly caused me the unpleasant position of 
being covered by several tons of gravel... . Having duly 
reported my find to Professor Putnam, I began at his request a 
thorough examination of the locality, and on May 25, 1888, 
the year following, discovered another implement, four feet 
below the surface, at a place about one eighth of a mile from 
the first discovery. . . . The geological formation at which 
the implement was found seems to be a reddish gravel mixed 
with schist. : | 


The implements thus discovered by Mr. Cresson in this 
early deposit of the Glacial period must be connected with 
others near by, found by him several years before in.a shel- 
ter-cave, since destroyed by the railroad excavation. This 
was situated near the small building that appears at the right 
of our picture.* Interested as a youth in the reports of 
cave explorations in Europe, he carefully excavated this rock 
shelter in 1866, making notes of and preserving everything 
he found. As recorded at the time, the lower part of this 
cave was filled to a depth of about six feet with a deposit ap- 
parently identical with the Philadelphia red gravel and brick- 
clay. This contained only paleolithic implements of argil- 
lite similar to those (figured on the following page) from the 
railroad cut near by. Argillite implements, mingled with 
others of jasper, quartzite, and bone, with fragments of pot- 


*See Fig. 183, p. 670; also “ Proceedings of the Boston Society of Natural 
History,” vol. xxiv, p. 145. 


674 THE ICE AGE IN NORTH AMERICA 


tery and human bones and charcoal, were found nearer the 
surface. The total depth of the deposit was about fifteen feet. 


1D 
- Pas y ii! 4 
ac a 4! / 


Fig. 185.—Argillite implement, found by H. T. Cresson, 1887, in Baltimore and Ohio Rail- 
road cut, one mile from Claymont, Delaware, in Columbia gravel, eight to nine feet 
below the overlying clay bed. a, face view ; 0, side view. (No. 45,726.) (Putnam.) 


The progress of the race from the Paleolithic to the Neo- 
lithic age here suggested corresponds in part to that indicated 
by Dr. Abbott’s discoveries at Trenton, where the transition 
from the paleolithic type of implement to the more modern 
types, though sudden at the top of the gravel itself, is gradual 
from the top of the gravel to the surface of the soil. For, 
according to him,* argillite implements occur in greatest 


* “ Procecdings of the American Association for the Advancement of Sei- 
ence,” vol. xxxvil. 


MAN AND THE GLACIAL PERIOD. 675 


abuudance at the base of the deposit of “ black soil” which 
overlies the gravel to an average depth of about one foot. 
“The flint implements known as Indian relies belong to this 
superticial or black soil,’ and they are found abundantly on 
the surface, more sparingly near the surface, and “more 
sparingly still the deeper we go,” until, on reaching the 
gravel proper, they disappear entirely. 

In this connection it is interesting to note that at the 
mouth of Naaman’s Creek, the nearest point on the river from 
the shelter-cave just described, Mr. Cresson has also discovered 
remains of prehistoric wooden structures below the level of 
low tide. These consist of the ends of rude piles which had 
evidently been fashioned by stone implements, but for what 
purpose intended it is not evident. In dredging here, he 
found numerous rude argillite implements of the paleeolithiec 
type, which, in the vicinity of two of the structures, were 
mingled with those of a modern type. 

Thus the valley of the Delaware would seem to contain 
a record of the passage of the race on the Atlantic coast 
from the Paleolithic to the Neolithic age. Here, about as 
far below the ice-front at that time as the shore of Greenland 
now is, the hardy hunters who had been driven before the 
advancing cold of the great Ice age found ample space for 
their pursuits, and excellent shelter in the dense forests which 
everywhere bordered the southern front of the great snow- 
tields. The proximity of the ocean furnished, doubtless, a 
supply of fish, while numerous animals, long since extinct in 
this region, were for a time fellow-fugitives with man from 
the advancing northern foe. Among these companions of 
man we may pretty certainly include the mastodon (one of 
whose tusks, as already remarked, was found by Professor 
Cook in the Trenton gravel itself), the walrus, the Greenland 
reindeer, the caribou, the bison, the moose, and the musk-ox, 
for the remains of all these animals are found either in the 
superficial gravel deposits of southern New Jersey, or in the 
adjoining region of country to the south and west. The 
picture of human life during that period in the valley of the 


676 THE ICE AGE IN NORTH AMERIC. 
Delaware is substantially the same as that presente 
archeologists of Europe for southern England and noi 
: p58 ‘ oes Er. eo Aa . ; ° “Oy 
France in the declining years of the Glacial period. 


X 
i 
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niet & 


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WA 


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s house and the relation of the bluff to the present flood plain of the Missouri River. (Courtesy of Records of the Past) 


LQ 
S 


SSS 
SWORE ROAR NRHN 


AQQ 


CESS 
SSAs“v“_ 


WOOL 


showing Mr, Concannon’ 


iew 


SQV 


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i 


CHAPTER XXIII. 
MAN IN THE MISSOURI VALLEY. 


Professor N. H. Winchell* has given a complete list of 
human remains supposed to have been found in the loess of 
the Missouri Valley, which belongs to the deposits of the 
Iowan stage of the glacial recession. But so much uncertainty 
surrounds several instances of these that it will be sufficient 
to mention only three of the best authenticated and most 
significant cases, viz., those found at Lansing, Kansas, and 
at Florence near Omaha, Nebraska, and at St. Joseph, Mis- 
souri. 

The important discovery at Lansing, Kansas, was made in 
February 1902, by Mr. Martin Concannon while excavating 
a tunnel underneath his residence, and was brought to the 
notice of the public by Mr. M. C. Long of Kansas City, Mis- 
souri. The skeleton was found seventy-two feet from the 


mouth of the tunnel. The excavation was carefully and - 


repeatedly examined by various expert geologists, including 


Professors T. C. Chamberlin, R. D. Salisbury, S. W. Williston, — 


EK. Haworth, N. H. Winchell. Warren Upham and W. H. 
Holmes. I can also speak fro: careful personal inspection 
ef the whole locality. Subsequently also Mr. Gerard Fowke 
and Mr. Long were engaged by Mr. Holmes to dig a cross 
section striking the tunnel near the place where the skeleton 
was found. The unanimous testimony was that the remains 
occurred as reported in undisturbed loess. In fact several 
other less important human relics were found by Mr. Fowke 
in his excavations. 


* “Records of the Past,’’ vol. vi (May 1907), pp. 148-157. 


yaaa 


aaa Se a en ee fe ee me 


MAN IN THE MISSOURI VALLEY. 679 


The only questions as to the glacial age of the relic is 
whether this remnant of loess belongs to the original deposit 
connected with the Iowan stage of glacial recession, or whether 
it may not have been re-deposited at some later stage of 
river erosion. Professor Chamberlin maintained that it was 
a secondary deposit, and that its antiquity “is measured by 


GEOLOGY 
OF THE CONCANNON FARM Ms N 
err y 
& | 
The Region is covered by the lowan Loess 6! 
With Kansan Drift onthe Uplands. “i 
a 
BERS 
oe 
N 
x. 
yd 
~ 
Bx 
Q 
N 
yi 


One Half Inch = 100 Feet. io 
Fig. 187. 


the time occupied by the Missouri River in lowering its bot- 
tom, two miles more or less in width, somewhere from fifteen 
to twenty-five feet, a very respectable antiquity, but much 
short of the close of the glacial invasion.”* But after three 
visits to the locality, Professor Winchell seems to show con- 
clusively that the loess belongs to the original undisturbed 


* “Journal of Geology,’’ October-November, 1902. 


680 THK ICE AGE IN NORTH AMERICA. 


deposit of Iowan age. My own personal investigations on 
the ground amply sustain this view as will appear from study of 
the accompanying illustrations. 

The remnant of loess is protected on a rocky promontory 
left between the main valley of the Missouri and a small 
stream whose channel dates from preglacial times. The 
stratum near the bottom of the tunnel in which the skeleton 
was found is between eleven and twelve feet above the extreme 
present highwater mark of the river, while the loess overlying 
the skeleton is twenty feet thick; and loess underlies the house 


Fre. 188—View showing entrance to tunnel in which the Lansing Skeleton was found 
(Courtesy of Records of the Past.) 


still several feet higher, and mantles the narrow slope well 
up to the 200 foot level constituting the loess plain which 
furnishes the location for the city of Leavenworth, a short 
distance away. West of the tunnel, also, the loess slopes 
rapidly upwards to the same level. 

The most conclusive witness to the original and undis- 
turbed character of the deposit in which the tunnel was exca- 
vated will be seen from a study of the accompanying map. 
The bottom of the tunnel is on a rock exposure of limestone 
whose outcrop extends from B to the side ravine, where, after 
a short iaterruption, it appears on the other side westward to 


MAN IN THE MISSOURI VALLEY. 681 


A, where the main tributary creek descends from the apex of 
a rocky gorge into what is evidently a preglacial portion 
extending 500 feet from A to C. There is no rock visible in 


Fic. 189—Front view of skulland femur bones of Lansing Skeleton. (Courtesy of Records 
of the Past.) 


the valley from A to C, and the water which in dry weather 
comes into its head continually disappears in the gravel 
underneath, whose surface at the entrance of the tunnel is 


Fre. 190—Side view of skull and femur bones of Lansing Skeleton. (Courtesy of Records 
of the Past.) 


twenty feet below the rock exposure, while a wella little farther 
east was sunk to a depth of twenty-four feet without striking 
rock, and the railroad immediately east of the mouth of the 


682 THE ICE AGE IN NORTH AMERICA. 


buried gorge is supported by piles driven thirty feet into | 


the alluvium. Above A this ravine lies wholly in the en- 
veloping loess. 

From this it is evident that the rock erosion in the lower 
part of the tributary entering at A is neither post-glacial nor 
interglacial, but is a remnant of preglacial erosion when the 
whole region was so much elevated that the river had lowered 
its bed a considerable depthbelow thatnow occupied by it. At 
Omaha the rock bottom of the river is known to be eighty 
feet below its present bottom. Since the advent of the con- 
tinental ice-sheet the preglacial gorge has been aggraded to 
a considerable extent, and meanwhile, during the Iowan stage 
of the glacial period the loess bluffs of the Missouri Valley, 
here so pronounced, were deposited on the ever rising flood- 
plain of the torrents which for many centuries poured out 
from the melting ice during the closing stages of the epoch. 
The Lansing skeleton antedates the deposition of the entire 
loess formation. 

Positive evidence of the aqueous character of the loess 
overlying the skeleton, was noted by Mr. Upham; namely, 
a ‘‘distinct darker layer of loess mostly about two inches thick 
but in part merely a threadlike line, traceable continuously 
through all the seventy-two feet of the west wall of the tunnel, 
running about three or four feet above the limestone floor, 
and one foot or a little more above the base of the loess.”’ 
This extended in a straight plane descending from,south to 
north about one inch to ten feet. Other lines of nearly horizon- 
tal stratification were also observed, thus clearly showing that 
it is an aqueous deposit of the same character with that of 
the loess of the whole valley. 


The most plausible suggestion for the later deposition has ~ 


been made by Professor J. E. Todd,* who thinks it possible 
that the loess on which the Concannon house stands may be 


* “Recent Alluvial Changes in Southwestern Iowa,’’ ‘‘ Proceedings 
of Iowa Academy of Science,’’ 1907, pp. 257-266. 


wil 
as ~ i *} 4 
aoe Darren EE 


MAN IN THE MISSOURI VALLEY. 683 


the remnant of a cone of dejection brought down from the 
adjoining loess terrace when the Missouri River was flowing 
on the opposite side of the trough, two miles distant. Some 
remarkable facts are given by him of the rapid growth of 
such cones in the Missouri Valley opposite Nebraska City, 
since the occupation of the country by whites. But the fact, 
just stated concerning the slight northward dip of the strati- 
fication noted by Dr. Upham, and the extent to which the 
remnant of the deposit runs up the ridge back of the house to- 
wards the main terrace would seem to render Professor Todd’s 
theory incredible. 

As to the skeleton itself, it so much resembles that of some 
modern American Indians, that the Americanists who exam- 
ined it at the International Meeting in New York, in the 
autumn of 1902, and later Professor Holmes and Mr. Hrdlicka 
think it incredible that it can be of glacial age. Their opinion, 
however, is largely discounted by the fact that greatly exag- 
gerated ideas of the antiquity of the glacial epoch are enter- 
tained by most of these experts. When the evidence is made 
to show that the date of the Iowan glacial episode did not 
close until about the time that the civilization of Egypt, 
Babylonia and Western Turkestan had attained a high degree 
of development, and that the cranial capacity had at that. 
time in those regions reached that of the higher races of the 
present time, there.would seem to be little dependence to be 
put upon 4 prior dicta adverse to the glacial age of the Lansing 
skull. 

The remains of the Nebraska Loess-Man were discovered 
in the summer of 1906, by Mr. Robert F. Gilder, who soon 
after called in Mr. E. H. Barbour, Professor of Geology in 
the University of Nebraska to make more extended investi- 
gations and give an expert opinion as to the age of the deposit. 

The locality of thisdiscovery is inthe township of Florence 
on the western loess bluffs of the Missouri River a few mikes 
aboveOmaha. Herefromtentotwenty feet of glacial drift rest- 


684 THE ICE AGE IN NORTH AMERICA. 


ing on a stratum of carboniferous limestone, is overlaid by 150 
feet of loess, making the elevation above the river 200 feet. 
Near the surface there were found many relics indicating 
recent interments. But at lower depths, reaching in some 
cases eleven and a half feet, bits of bone were found. Be- 
low a depth of five feet there was no evidence that the loess 


Fic. 191—Section of Long’s Hill, Nebraska. The man is pointing to the base of the loess 
resting upon 40 feet of till. (Courtesy of Records of the Past.) 


had been disturbed subsequent to its deposition, since here 
the characteristic vertical lime tubes and concretions were 
everywhere present. Moreover the fragments of bones were 
widely scattered, only five or six fragments being found to a 
cubic yard, and some of these evidently were water worn. The 
prize specimen was that of a skull broken, disarticulate and 


MAN IN THE MISSOURI VALLEY. 685 


scattered over a space of twenty-five square feet, between four 
and five deep in the undisturbed loess. The walls of this 
were thick, measuring as much as three-eighths of an inch. 
Counting all the fragments, Professor Barbour estimates that 
there are probably ten or twelve individual skulls represented 
in this loess bone bed and that comparison shows them to be 
of the Neanderthal type, with thick cranial walls.* 

Weare bound to say, however, that the glacial age of these 
relics, like everything else of much moment in scientific dis- 
covery, has been disputed by high authorities. Inthiscaseit has 
been done by Professor B. Shimek,f an accomplished investi- 
gator of land shells. From study of these in the loess deposits 
of the region he has become an ardent advocate of the zolian 
hypothesis respecting the distribution of loess, and hence 
approaches the question with the bias of that theory. For 
a general discussion of the £olian hypothesis the reader is 
referred to the chapter on the Loess. Itissufficient to say here 
that it is hardly possible that so experienced an authority as 
Professor Barbour, and one so familiar with the loess of the 
region could be mistaken in the matter. His excavations 
were extensive, and most carefully made, and his conviction 
of the undisturbed character of the portion of the deposit in 
which the remains were found was unequivocal. Professor 
Shimek’s judgment in the case is also greatly discounted by 
his equally positive, but certainly, erroneous opinion that the 
deposit in which the Lansing skeleton was found was clearly 
distinct from ordinary undisturbed loess, ‘‘ evidently consisting 
of slumped material.’”’ In short there is no valid reason to 
doubt the glacial age of the loess in which the remains of the 
Nebraska man were found. 

The relic described by Miss Owen is an implement of 
paleolithic type, chipped from a porphyritic pebble (probably 


* “Nebraska Geological Survey,”’ vol. ii, part 5, pp. 318-327; part 6, 
pp. 331-348. Also ‘‘Records of the Past,’’ vol. VI, Feb. 1907, pp. 34-39. 

T ‘‘Bulletin of Geological Society of America,” vol. xix, pp. 243- 
254, 1908. fyite 


686 THE ICE AGE IN NORTH AMERICA. 


from the Black Hills, Dakota). The illustration speaks for 
itself. This was found projecting from the face of an old 
cut for a road through the loess in the northern part of the 
city of St. Joseph, Missouri. It was found not less than twenty 


Fie. 192—Implement from Dug Hill. (Miss Owen). 


feet below the surface where there could be no question con- 
cerning its undisturbed character. This is on the east side of 
the Missouri River, where the total depth of the loess is more 
than 100 feet.* : 

* “Records of the Past,’’ October. 1907, pp. 289-292. 


atthe 


ET se a ll ae Tiss ap 


te ee 


a a 


CHAPTER XXIV. (Concluded). 
MAN AND THE LAVA BEDS OF THE PACIFIC COAST. 


The occurrence of human relics in the auriferous gravels 
of California, where in some places they are capped with ex- 
tensive lava overflows, though still a subject under hot 
discussion is too important and interesting to be passed over 
without a full detail of the facts. The connection of these 
facts with the glacial epoch, though inferential, is by no means 
uncertain; for, confessedly, the lava flows west of the Rocky 
Mountains, though commencing early in the tertiary period, 
have continued in great volume down to very recent times, 
some extensive eruptions having occurred in California and 
Idaho within the last two or three hundred years; while the 
remains of extinct animals found in the auriferous gravels are 
substantially the same as to be found in the glacial deposits 
of the eastern United States and Europe. At the same time 
the indications are clear that the glaciers of the Sierras in 
California and elsewhere extended greatly beyond their present 
limits down to a period of time separated from us by only a 
few centuries. Nor should the existence of unbelief, on the 
part of many, prevent a candid consideration of the facts, 
for 1t is pre-eminently a question of evidence such as is em- 
ployed in all historical investigations, and so, open to chal- 
lenge. But we are convinced, it is beset with difficulties 
no greater than pertains to all investigations of a similiar 
nature. 

The incredulity prevailing concerning these facts will 
largely disappear upon consideration of the evidence of re- 


688 THE ICE AGE IN NORTH AMERICA. 


cent activity of volcanic forces on the Pacific Coast, and of 
the recency of the disappearance of the glaciers from the 
mountains of the region. All competent observers have re- 
marked the freshness of the lava deposits in the Snake river 
Valley in Idaho, while Mr. Diller* has shown that in the 
great interior basin in California near Lassen Peak, between 
Snag Lake and Lake Bidwell, there is a region many miles in 
extent covered with lava and volcanic ash to a uniform depth 
of many feet, with conesrising more than 600 feet, all of which 
must have been ejected within the last 200 years. Stumps 
of trees are still projecting from the stratum of volcanic ash 
which killed them, while the charred trunks of other trees 
which were overwhelmed by the lava stream still remain 
undecayed. It is impossible that these trunks could have 
resisted the corroding agencies even of this dry atmosphere 
for many centuries while none of the fresh trees growing on the 


surface of the stratum of volcanic ash are more that 200 years. 


old. 
It should be remembered also that the vast erosion since 
the auriferou gravels were covered by lava was hastened by 


the enormous floods which occurred when the glaciers which 


had been subsequently formed melted off. The floods aris- 
ing from the annual melting of the snow in the region are now 
enormous. How much greater must they have been in the 
declining years of the Glacial Epoch! 

The first evidence upon the point to which we will turn 
attention is that produced by Professor J. D. WhitneyT of 
Harvard University, concerning human remains believed by 
him to have been found in strata which mark the closing 
period of the Tertiary epoch in California. 

The following description of the deep placer deposits in 
_ which these remains have been found is given by Le Conte: 


i See “Bulletin of U. 8S. Geol. Survey,’’ No. 79, 1891. 


+ ‘‘Report on the Auriferous Gravels of the Sierra Nevada,’’ 1879, 
p. 258 ef seq. 


fe, AE ei 


MAN AND THE LAVA BEDS. 689 


There are in many parts of California two systems of river- 
beds, an old and a new. The old belongs to the Tertiary ; the 
new, to the Quaternary and present. The change took place 
during the oscillations of the Quaternary. The old river-system 
is substantially parallel to the present river-system, though in 
some places the one cuts across the other. It is probable, 
therefore, that there was but little change in the general direc- 
tion of the slope, produced by the oscillations of this epoch. 
These old river-beds are filled with drift-gravel, and often cov- 
ered with lava-streams. These drift-gravels probably repre- 
sent the beginning of the Glacial epoch, though Whitney 
thinks an earlier or Pliocene epoch. The present river-system 
sometimes cuts across, sometimes runs parallel to, the lava- 
filled beds of the old river-system, and the beds of the former 
have in their turn been eroded two thousand to three thousand 
feet in solid rock. In these also have been accumulated im- 
mense quantities of gravel and bowlder drift, evidently brought 


R SEATED — 
rt 


Sar CANTO TA & 


: oe see set raters 4 Ry MINT 
SSN Seb OR MT SR’ 
EN 
S SSN 


——S = — 
————— 
——— ———S 


Fie. 193.—Lava-stream cut through by rivers ; a, a, basalt ; b, b, volcanic ashes ; ¢, ¢, ter- 
tiary ; d,d,cretaceous rocks ; 2, RF, direction of the old river-bed ; R’, R’, sections of 
“the present river-beds. (Le Conte from Whitney.) 


down from the glacial moraines by the swollen rivers of the 


Champlain and early Terrace epochs. These facts are illus- 
trated by Figs. 193 and 194, in which R#’ represents the present 


+ oer ee ree, 
- _ os 


-_----— 

- 

So eae eR 
- 

-— ~ 


<— ee - 


--— 
Re 
Sr 


5 | a ‘ff ! " R & 1 ; 
i Divina |! H | | MR | 


Fic. 194.—Section across Table Mountain, Tuolumne County, California. 0b, lava ; G, grav- 
el; 8, Slate ; R, old river-bed ; #’, present river-bed. (Le Conte.) 


river-system, in Fig. 193, cutting across, and in Fig. 194 run- 
ning parallel to, the old system R. 
Although it is impossible to synchronize with certainty 


690 THE ICE AGE IN NORTH AMERICA. 


these events with the changes in the eastern portion of the 
continent, yet the order of sequence is evident ; and that the 


greater part, if not all, occurred in the Quaternary, is also evi- 


dent... . 

The history of changes shown in these sections is suffi- 
ciently obvious. In the time of the old river-system, & was a 
river-bed, doubtless with a ridge on either side represented by 
the dotted lines. In this bed accumulated gravel, containing 
gold. Then came the lava-flow, which of course ran down the 
valley, displacing the river and covering up the gravels. The 
displaced rivers now ran on either side of the resistant lava, 
and cut out new valleys, two thousand feet deep, in the solid 
slate, leaving the old lava-covered river-beds and their aurifer- 
ous gravels high up on aridge. In other cases the convulsion 
which ejected the lava also changed greatly the general slope 
of the country, and therefore the direction of the streams. In 
such cases of course the present river-system cuts across the 
old river-beds and gravels, and their covering lavas, as shown 
in Fig. 142. 

The age of the old river-gravels is still doubtful ; that of 


the newer river-gravels is undoubtedly Champlain or early Ter- - 


race. Below we give a list, taken from Whitney, of the re- 
mains found in these gravels : 

Newer Placers.—Great mastodon, mammoth, bison, tapir 
(modern), horse (modern), man’s works. 

Deep Placers.—Great mastodon,* mammoth, tapir (mod- 
ern), rhinoceros (ally), hippopotamus (ally), camel (ally), horse, 
extinct species. 

It will be seen that the fauna of the deep placers unite Pli- 
ocene and Quaternary characters. The great mastodon, the 
mammoth, and the tapir, are distinctively Quaternary, while 
the others are Pliocene. The plants, according to Lesquereux, 
are decidedly Pliocene. Therefore Whitney has not only placed 
the deep placers in the Pliocene, but made them the repre- 
sentative of the whole Pliocene, and probably Miocene, and 
the lava-flow as the dividing-line between the Tertiary and the 


* Whitney states that the mastodon is not found here, but it has been 
since found. 


MAN AND THE LAVA BEDS. 691 


Quaternary. But, all the facts considered, it seems most prob- 
able that both the filling of the old river-beds, and their pro- 
tection by lava, took place comparatively rapidly, and were 
together the closing scene of the Tertiary drama. The deep 
gravels, therefore, may be placed indifferently in the latest 
Phocene or earliest Quaternary. The newer gravels are un- 
doubtedly Quaternary and recent. Certain it is that the deep 
placer-gravels are similar in all respects to the Quaternary 
gravels all over the world, except that, by percolating alkaline 
waters containing silica, they have been cemented in some 
cases Into grits and conglomerates. This is because they are 
covered with lava which yields both the alkali and the soluble 
silica. 

In any case, we have here an admirable illustration of the 
immensity of geological times. The whole work of cutting 
the hard slate-rock two thousand feet or more has been done 
siuce the lava-flow, and therefore certainly since the beginning 
of the Quaternary.* 


It will readily be seen that these upper gravels, whether 
we call them Tertiary or Quaternary, are with reference to 
the historical period very ancient, though recent if spoken 
of from a geological point of view. The question of man’s 
antiquity does not turn on the name of the formation ; but 
upon the reality of the existence of his remains in the upper 
gravels. Indeed, there does not seem to be any hard-and- 
fast line of demarkation between the Tertiary formation and 
the Quaternary, or recent. In making chronological calcula- 
tions from the vast amount of erosion spoken of in the pre- 
ceding paragraph, Le Conte warns us, however, to note the 
prodigious rapidity with which erosion now proceeds in con- 
nection with hydraulic mining. “In the North Bloomfield 
mine, the pebble-loaded torrent resulting from the incessant 
play of the hydraulic jet against the cliff, though working 
but eight months per year, has cut in four years a channel 
three feet wide and fifty feet deep in solid slate.” + 


* Le Conte’s “ Elements of Geology,” 1888, pp. 555, 585. 
¢ “ American Journal of Science,” March, 1880, vol. exix, p. 179. 


692 THE ICE AGH IN NORTH AMERICA. 


Unfortunately, the evidence that human remains have 
been taken from beneath these lava-capped mountain-ridges 
is neither of recent date nor that of professed geologists. 
‘We are compelled to depend upon the testimony of plain 
miners, exhibiting what they found and recounting what 
they saw several years ago. ‘This fact, which needs expla- 
nation, is said to arise from the wholesale changes in the 
methods of mining introduced by hydraulic processes. By 
present methods terraces are washed down into a promiscu- 
ous heap by jets of water forced against them with great ve- 
locity, so that there is little hope of finding the archeologi- 
cal specimens they may have contained. The golden days 
for the archeologist in California have passed by. Still, so 
many independent witnesses from different localities have 
testified to the facts which we now relate, and circumstantial 
evidence so fully corroborates the statements of the witnesses, 
that Professor Whitney and_his associates think they are be- 
yond question.* 

As early as 1863 Dr. Snell, of Sonora, began a systematic 
collection of animal and human remains from the mines in 
his vicinity. In his collection were several objects marked as 
“From under Table Mountain,’ among which was a human 
jaw. Dr. Snell’s collection was destroyed by fire, and he 
died in 1869; but Professor Whitney and Mr. Voy had 
repeatedly examined it and conversed with him. A stone 
utensil, apparently used for grinding, was the only one 
‘which Dr. Snell claims to have taken with his own: hands 
from the dirt as it came out of the tunnel under the mountain. 

In 1857 Hon. Paul Hubbs, of Vallejo, Cal. (subsequently 
‘a State Superintendent of Public Instruction), picked a por- 
tion of a human skull out of the dirt as it was brought from 
the Valentine shaft, under Table Mountain, near Shaw’s Flat. 
This skull was given to Dr. C. F. Winslow, who soon after 
(October 7, 1857) divided it, and sent one piece to the Phila- 


* A few paragraphs are here substantially reproduced from my “ Studies in 
Science and Religion,” p. 285 et seq. 


MAN AND THE LAVA BEDS. 693 


delphia Academy of Sciences and the other to the Boston 
Society of Natural History, where it still remains, and in 
whose “* Proceedings ” (vol. vi, p. 278) Mr. Winslow’s original 
communication may be found. 

Ten years after, Mr. Hubbs more fully detailed -the cir- 
cumstances of the discovery, and Professor Whitney and 
Gorham Blake, Esq., made special examination of the locality 
and careful inquiries of the owners of the mine, and satistied 
themselves that the bone really came from under the basaltic 
covering of Table Mountain. Mr. Walton, one of the owners, 
did not remember anything about the bone, but did remem- 
ber that a “mortar” had been found in the tunnel, near 
the same situation. 

In 1870 Mr. Oliver W. Stevens gave to Mr. Voy a large 
stone bowl, which was incrusted with sulphuret of iron, and 
which he makes affidavit that he picked with his own hands, 
in 1853, from a load of dirt which came from a tunnel under 
Table Mountain, two hundred feet in, at Shaw’s Flat. 

Mr. Llewellyn Pierce also makes affidavit that a certain 
stone mortar which he gave to Mr. Voy was taken, in 1862, 
from under Table Mountain, eighteen hundred feet from the 
mouth of the tunnel. 

All this is preliminary to the famous Calaveras skull, the 
facts about which are as follows : 

In February, 1866, Mr. Mattison, one of the owners of 
a claim on Bald Mountain, near Altaville, says he took from 
a tunnel under the basaltic capping of the mountain an ob- 
ject which, on account of incrusted earthy and stony ma- 
terial, he thought at first to be the petrified root of a tree, 
but which he discovered to be a portion of a skull. He took 
it to Mr. Scribner, agent of the express company, who, after 
seeing the importance of the discovery, passed it over to Dr. 
William Jones of Murphy’s, a physician of extensive practice 
and scientific tastes. Both these gentlemen were well known 
to Professor Whitney, and their veracity is vouched for by 
him. The skull was forwarded by Dr. Jones to the offiee 
of the State Survey on the following June (1866). Mr. Mat- 


694 THE ICE AGE IN NORTH AMERICA. 


tison has been repeatedly interviewed, and his testimony is 
uniformly coherent and explicit, to the effect that he took 
the skull with his own hands from gravel underneath a cap- 
ping of forty feet of black lava and in connection with drift- 
wood. ‘The appearance of the skull in every way corrobo- 
rates his statement. The original incrustation shows that it 
was not taken fromacave. The late Dr. Wyman, of Harvard 
College, and Professor Whitney together carefully removed 
the incrustations from the skull. Fragments of bones and 
gravel and shells were so wedged into the cavities of the 
skull as to satisfy them that there could be no mistake as to 
the character of the situation in which it was found. Chemi- 
cal analysis showed that organic matter was nearly absent, and 
the carbonate of lime had largely displaced the phosphate ; 
i. e.,1t was in a fossilized condition. 

In a visit to Sonora, California, and to Bald Mountain, where 
the Calaveras skull was discovered, I was so fortunate also 
myself as fo run upon evidence of a previously unreported 
instance of the discovery of a stone mortar under ‘Table Mount- 
aim. The mortar was found in October, 1887, by Mr. C. 
Mc'Tarnahan, the assistant surveyor of Tuolumne county. It 
was lying in the gravel reached by the Empire Tunnel, and 
about a mile west of the Valentine shaft mentioned on page 
692. ‘T’his tunnel had been excavated 758 feet before reaching 
the gravel, and the mortar was found 175 feet in a horizontal 
line from the edge of the Table Mountain basalt, and about 100 
feet below the surface. The object was taken out and laid 
beside the mouth of the tunnel, and was given to Mrs. M. J. 
Darwin, of Santa Rosa, Cal., who has given it to me. The 
mortar is made from a bowlder of some eruptive rock, and is 
six and a half inches through; the hollow: being about three 
and a half inches in diameter, and about three inches deep. 

‘This mortar is now in possession of the Western Reserve 
Historical Society of Cleveland Ohio. An account of the 
discovery was given to the Geological Society of America, at 
Washington, in 1891. 

At the same meeting Mr. George F. Becker of the U. Ss. 
Geological Survey, presented the affidavit of Mr. John H. 


Bess, Seth i he ee ee ae 


Pt 2 i a — . 
Pe OE ie GD ee 


— 2 i 


MAN AND THE LAVA BEDS. 695 


Neale, a mining engineer of much experience and high reputa- 
tion, to the effect that in 1877 while running the Montezuma 
tunnel into the gravel underlying the lava of Table Mountain, 
Tuolumne County, near Rawhide Gulch, and when 1,400 feet 
from the mouth of the tunnel and between 200 and 300 feet 
from the edge of the solid lava, he found several spear heads 
of some dark rock and nearly one foot in length, and, near by, 
_ two mortars and a pestle. 

“Mr. Neale declares it utterly impossible that these relics 
can have reached the position in which they were found ex- 
cepting at the time the gravel was deposited, and before the 
lava cap formed. There was not the slighest trace of any 
disturbance of the mass or of any natural fissure into it by 
which access could have been obtained either there or in the 
neighborhood.’’* 

With regard to this evidence Mr. Becker justly remarked 
that the mining engineer is of all persons in the world best 
fitted to determine whether the gravel in such a tunnel had 
been disturbed, for the chief danger in such mining arises 
from penetrating old drifts. Therefore a geologist would 
rather trust an engineer’s testimony in such a case than his 
own. | 

The only reason found by Mr. Sinclair (whose general 
criticisms will be given later) for doubting the facts as here 
stated arises from the circumstances that the mortar of 
andesite and the spear heads of obsidian are found in pre-vol- 
eanic gravels. But this objection overlooks the fact that there 
was extensive commerce between the aboriginal tribes, and 
that the outflows of lava were by no means contemporaneous 
in different parts of the Pacific coast. Obsidian, for example, 
is found in large quantities in the mounds of Ohio, two thou- 
sand (2000) miles from any original deposit of the material. 

Another bit of evidence from the same vicinity was pre- 
sented by Mr. Becker at the same meeting of the Geological 


* ‘“‘Bulletin of Geological Society of America,”’ vol. ii, p. 192. 


696 THE ICE AGE IN NORTH AMERICA. 


Society. . This was a broken pestle found by Mr. Clarence 
King and taken with his own hands from undisturbed gravel 
under Table Mountain in the vicinity of Tuttletown not 
far from Rawhide Gulch. As Mr. King was a geologist of 
the highest reputation this would seem to be convincing 
evidence. But it is suggested that he may not have given 
attention to the question whether there had not been secondary 
cementation of the gravel, so that this may possibly have 
been in a talus. It is, however, hardly to be supposed that so 
experienced a geologist as Mr. King would have failed to 
notice a point of so much importance. 

As already remarked the fact that new discoveries do not 
continue to be made in the auriferous gravels is readily ac- 
counted for from the fact that the profitable mines where such 
relics would be likely to be found have been worked out, and 
hence such mining has ceased. 

The gravels under Table Mountain have not yielded enough 
gold to pay for the mining, and hence have been abandoned, 
while hydraulic mining so mingles the débris washed down that 
the discovery of implements in place is practically out of 
the question. Still, important discoveries do now occur. 

In “Science” for March 6, 1906, Mr. J. F. Kemp, of the 
U.S. Geological Survey, reported the discovery of mortarsand 
pestles in the auriferous gravels at Waldo, Josephine County, 
Oregon. The discoveries which he reports were made in 1901 
and 1902. The latter was brought out by the miners during 
the night shift from 58 feet below the surface, where it was 
embedded in ‘‘the blue cement gravel’”’ of the ‘‘ pay channel.” 
So firmly was it embedded that they had to resort to picks 
to extricate it and ‘‘the bed or hole out of which they pulled 
itremained, showing itsperfect mould. ‘“Inthemorning,” says 
Mr.W. J. Wimer, the manager (who carefully noted the facts), 
“it was still packed tightly to its very rim-with blue cement 
gravel’ which after being carefully picked out yielded several 
“large colors of gold.’”” The mortar is about twelve inches 


= ti ei 


MAN AND THE LAVA BEDS. 697. 


high by nine inches across, and is made of the hardest granite. 
Pestles were found in this deposit often enough to cause no 
surprise. In 1901 another mortar with some pestles had been 
found ten ee under the surface and about 300 yards oe this 
in the same “pay dirt.’ 


Fig. 195—McTarnahan Mortar from under Table Mountain 


We omit mention of a large number of human remains 
found at great depths in the ancient higher-level gravel where 
not covered with lava, though some of them are doubtless of 
the same age with those from under Table Mountain. 

According to Professor Whitney, the evidence “all 
points in one direction, and there has never been any at- 
tempt made to pass off on any member of the Survey any- 
thing out of keeping or, so to speak, out of harmony with 
what has been already found, or might be expected to be 
found. It has always been the same kind of implements 
which have been exhibited to us—namely, the coarsest and 
the least finished which one would suppose could be made, 
and still be implements at all.” This result, he cogently re- 
marks, would hardly be possible where so many parties are 
concerned in furnishing the evidence, if the objects were not 
genuine, and shows to his mind that the evidence has not 
been got up to deceive. 

As might be expected, strenuous efforts have been made 
to discredit these facts. With reference to the Calaveras 
skull, we read in Dr. Southall’s “ Recent Origin of Man” 
(p. 558) that “ Dr. Andrews informs “1s [Dr. Southall] that 
the Rev. R. W. Patterson, D. D., of Chicago, tells him that 


* “Records of the Past’’ vol. v, June, 1906, pp. 190-191. 


698 THE ICE AGE IN NORTH AMERICA. 


he was informed by the Rev. W. W. Brier, a reliable minister 
of Alvarado, Oal., that his [Brier’s] brother, a miner, was 
one of two men who took the so-called Calaveras skull from 
a cave in the side of the valley, and placed it in the shaft, 
where it was found, and that the whole object was a prac- 
tical joke to deceive Professor Whitney, the geologist.” 
Whether this is probable can be judged from the foregoing 
statement of facts as since detailed by Professor Whitney. 
At any rate, it would have been the proper thing for this 
renegade brother of the Rev. Mr. Brier to have submitted 
himself to closer cross-examination from competent parties 
than he seems to have done. : . 

Sir William Dawson and others have questioned whether 
these human remains might not have been introduced at a 
period subsequent to the deposition of the gravel and the 
overflow of the lava. They have suggested that the Indians, 
in searching for gold, may have run horizontal shafts into 
the gravel underneath ; or, since the lava is not compact but 
tufaceous in its character, it does not seem impossible that, 
in some places, pits may have been sunk from the surface. 

The most formidable opposition to Professor Whitney’s 
conclusions comes, curiously enough, from evolutionists, so 
that, upon this question, they are now found ‘‘among the 
prophets.” The thorough-going evolutionist believes that 
early man was ape-like in his features, and that he invariably 
passed through a stage in which he used rough stone imple- 
ments before learning to polish them. But the Calaveras 
skull, which, if genuine, far antedates anything human 
which has been discovered in Europe, is not of a particularly 
inferior order, and the implements purporting to come from 
under Table Mountain are not of the paleeolithic type, but, 
though exceedingly coarse and rude, correspond to those of 
the smooth stone period in Europe. Professor Putnam, 
however, suggests,* and Professor A. Winchell is ready to 


* “Report of the United States Geological Surveys west of the One Hun- 
dredth Meridian,” vol. vii, pp. 10-15. 


MAN AND THE LAVA BEDS. 699 


admit,* that man wandered into California long before he 
entered Europe, and attained there the higher state of devel- 
opment reached by paleolithic man in other parts of the 
world at a much later date. 

The objection to Professor Whitney’s inferences arising 
from the possibility that the aboriginal inhabitants of that 
region themselves carried on mining operations for the sake 
of obtaining this gold is presented, in a convincing manner, 
by Dr. James Southall. According to him,t Bancroft, in 
his “ Native Races of the Pacific States,” refers to it asa 
well-known fact that mining operations were carried on in 
Mexico to a great extent, opening galleries into the sclid 
rock, in some cases two hundred feet or more in depth; and 
Schooleraft, in his “ Archeology,” | describes one of these 
ancient shafts, which was discovered in 1849. This was two 
hundred and ten feet deep, and its mouth was situated on a 
high mountain. “The bones of a human skeleton were 
found at the bottom. There were also found an altar for 
worship and other evidences of ancient labor.” 

It is to be observed that, in the quotation from School- 
craft made by Bancroft, it is stated that “no evidence has 
been discovered to denote the era of this ancient work. There 
has been nothing to determine whether it is to be regarded 
as the remains of the explorations of the first Spanish advent- 
urers, or of a still earlier period. The occurrence of the re- 
mains of an altar looks like the period of Indian worship.” 
Professor Putnam, however, writes me: “I think there is a 
strong objection to the ancient mining theory, inasmuch as 
we do not know of gold among the Californian Indians. The 
Mexicans had it, but did they mine it in California? The 
stone mortars we find in the California gravels are not of 
Mexican type, but of Californian type, the same form used 
in recent times.” 


* “ Pre-Adamites,” p. 428. + “Pliocene Man in America,” p. 7. 
¢ Vol. i, p. 105. For a full summary of facts see Bancroft’s “ Native Races 
of the Pacific States,” vol. iv. 


700 THE ICE AGE IN NORTH AMERICA. 


A more serious arraignment of this whole evidence is 
made by Professor W. J. Sinclair of Berkely, California. 
It is unnecessary to review the whole of Mr. Sinclair’s 
argument in detail. But in general it is sufficient to say that 
it is mainly occupied with throwing doubt upon the sufficiency 
of the evidence in eachof the many individual cases of alleged 
discovery reportedby Professor Whitney and others, but fails 
to break the force of the cumulative evidence arising from the 
great number of instances. For, it is highly improbable that 
so many cases each with so great probability would have been 
fabricated from such widely separated places. The theory of 
fraud in so many separate instances agreeing in the main 
point of contention yet differing so much in detail is exceed- 
ingly improbable. While the supposition that the gravels 
underneath the lava deposits had been previously worked 
over almost the whole area, is equally improbable. | 

But in particular it must be admitted that there has been 
a mistake in respect to the Caliveras skull reported to have 
been found by Mr. Mattison. The skull examined by Pro- 
fessors Whitney and Wyman and now in possession of the 
Peabody Museum of Harvard University evidently did not 
come from under the lava deposits described by Whitney as 
occurring at Bald Hill. For, Mr. Sinclair’s examination of 
the skull and of the incrustation enveloping it shows that it 
must have come from some cavern in the vicinity used by 
the Indians as a sepulcher. Hence it follows that if Mr. 
Mattison actually took a skull from his drift under Bald Hill ~ 
some other skull must have been substituted for it in the 
course of transmission. Thatthis could have been done under 
the circumstances without impeaching the honor of any of the 
parties involved is readily seen from a fuller statement of 
some of the circumstances. Such, at any rate is the opinion 
of Professor Putnam. (See Sinclair’s paper above quoted, 
p. 129). In confirmation, I may state that in 1890 when I 
visited Mr. Scribner he gave me the story substantially 


MAN AND THE LAVA BEDS. 701 


as Professor Whitney relatesit, but with some additional details 
bearing specially upon the points here raised though they had 
not been raised at that time. He said to me that when he 
gave the skull to Dr. Jones, soon after Mr. Mattison had given 
it to him, he was not able to furnish the particulars to the 
Doctor, as at the time he was not impressed with its impor- 
tance. Dr. Jones, therefore, put it outside his office, with 
other collections of a similar sort, where it lay for several 
months until Mr. Mattison came to him one day for medical 
treatment, whereupon he asked him the particulars about the 
discovery of the skull, which he then forthe first time learned. 

This, therefore, makes it possible that while Mr. Mattison 
found a skull as he asserts he did and gave it to Mr. Scribner 
the wrong one was selected from Dr. Jones’ pile, sothat nothing 
is known now of the nature of the true skull or of the incrusta- 
tion upon it. But that Mr. Scribner or Dr. Jones endeavored 
to impose upon Professor Whitney, is not credible from the 
known character of the men, and from their behavior in the 
whole matter; while there would have been no motive for 
any one to have imposed upon poor Mr. Mattison who was 
spending his last cent in vain efforts to find gold. And cer- 
_ tainly, he made no effort to profit from thealleged discovery. 
It follows simply that we must drop out of the discussion 
everything that has been heretofore been said about the 
eharacter of the skull. With that absent the discovery 
reported by Mr. Mattison becomes more easily credible than 
it was before. 


A discovery in Idaho strongly confirmatory of tnose on the 
Pacific Coast is too important and interesting to be omitted. 

In the autumn of 1889, Mr. Charles Francis Adams, then 
President of the Union Pacific Railroad, brought to my notice 
a small clay image, an inch and a half in length, which had 
been found by Mr. M. A. Kurtz while boring an artesian well 
at Nampa, Ada county, Idaho. The image was of slightly 
baked clay, incrusted in part with a coating of red oxide of 


702 THE ICE AGE IN NORTH AMERICA. 


iron, which indicated considerable age, and came up in the 
sand-pump from a depth of three hundred and twenty feet. 
Near the surface the well penetrated a stratum of basalt, fifteen 
feet thick. Below this basalt there were alternate beds of clay 
and quicksand to the depth mentioned, where the sandstone 
rock was encountered. The well was tubed with heavy iron 
tubing six inches in diameter, so that there could be no mistake 
about the occurrence of the image at the depth stated. The 
detailed evidence was published by me in the “ Proceedings of 
the Boston Society of Natural History” for January, 1890. 
During the following summer, I visited the locality and found 
ample confirmation of it. 

It is proper also to be stated that Mr. G. M. Cumming, 
general manager of the Union Pacific lines in that district was 
on the ground the day the “find” was made, and carefully 
scanned the evidence, with the conclusion that there was no 
doubt of the facts as given. Probably no person in the world 
was better able than he to judge of the evidence. Later, other 
officials of the railroad who had interests in the vicinity took 
pains at my suggestion to re-examine the evidence with the 
result of confirming it in every respect. On the other hand, 
no one has come forward to challenge the evidence except on 
purely @ priori grounds arising from preconceived opinions 
of the extreme antiquity of the deposits in which it is said ~ 
to have been found. Close attention to the accompanying 
conditions will, however, I think modify these preconceptions. 

In the valley between the Boisé and Snake Rivers, in south- 
western Idaho, where Nampa is situated, there is an area of sey- 
eral hundred square miles covered with fresh-appearing basalt, 
which apparently came from vents thirty or forty miles to the 
east, but in its western flow barely extended five miles beyond 
Nampa. Below that point there is no lava for seventy miles. 
The clay and quicksand covering the stratum in which the 
image was found would seem to have accumulated in the valley 
of a stream having access to such an amount of sedimentary 
material that for a time it filled up rather than eroded its chan- 
nel. Apparently the conditions favorable for such effects would 


+ 


MAN AND THE LAVA BEDS. ~ 703 


be most readily furnish during the Glacial period, when the 
streams of that region were swollen not only with the in- 
creased annual precipation, but with the melting of the 
glaciers which doubtless had for a long time occupied the 
mountains near the head-waters of the Boisé River to the 
north. Very likely, also, the lava-flows which obstructed 
the river a few miles above Boisé City turned its course to 
the southward, so that it may have wandered for some time 
over the plain in the vicinity of Nampa. 


Fic. 196—Nampa figurine and map of the Snake river valley illustrating the text. 
For photograph of the bowlder bed at Pocatello described in the text, see page 615. 


In addition to these general considerations we have here 
a most interesting and suggestive special situation from which 
much evidence may be derived in support of the foregoing 
interpretation of the facts. In the summer of 1890, while 
making investigations in the Snake River Valley at Pocatello, 
350 miles above Nampa, and where the elevation is 2000 feet 
higher, I was confronted with an immense delta of bowlders, 
many of them three and four feet in diameter, at a consider- 
able distance from the foot hills of the mountains to the south, 
which seemed inexplicable from any natural causes within 


704 (HE ICE AGE IN NORTH AMERICA. 


my knowledge. This delta of bowlders had been covered with 
a thin deposit of loam, and the city of Pocatello was built 
uponit. While I wasthere the city authorities were endeavor- 
ing toputin asewersystem, but were impeded by thegeneral 
occurrence of these obstructing bowlders of great size. This 
bowlder bed is just where the Port Neuf River debouches 
upon the Snake River Plain. But upon going up the tributary 
valley a half mile or so the large bowlders ceased, and there 
was a scoured out channel free from them. | 

The explanation of this puzzling phenomenon was soon 
found in the result of Mr. Gilbert’s investigations respecting 
the history of Lake Bonneville, to which reference has already 
been made. It was through the Port Neuf River that the 
great debacle from Lake Bonneville poured when the rising 
water surmounted the 1000-foot dirt barrier which retained 
the upper 350 feet of water over an area of 20,000 square 
miles. Mr. Gilbert estimates that it would require twenty 
years for a stream as large as Niagara to lower this body 
of water to the bottom of the dirt dam which was finally 
broken through, and that a stream as large as that did mean- 
while pour through the opening leading to the Port Neuf, 
and so on into the Snake River Valley at Pocatello. Here, 
therefore, we have not only an adequate cause for the bowlder 
bed at Pocatello with all its peculiarities, but for the seemingly 
anomalous facts in the valley at Nampa 350 miles below, and 
at a level 2000 feet nearer that of the sea. The conditions 
were such as to favor the rapid accumulation of fine sediment 
which appears above the mouth of Boisé River, and above the 
great constriction of the channel which occurs a short distance 
beyond at Huntington, and continues for a long distance 
below. Sh 

Light is shed upon the geological date of this debacle by 
the fossils found at Glens Ferry, about half way between Po- 
catello and Nampa, and described by Dr. Dall. They are as 
follows: Goniobasis taylort Gabb (sp.), Lithasia antiqua Gabb, 


MAN AND THE LAVA BEDS. 705 


_Latia dalli White, Sphoerium idahoensis Meek, and S. negosum 
Meek. 

These are found in consolidated gravel 100 feet beneath 
a thick capping of lava. The elevation of the lava here is 
400 feet above that at Nampa, 85 miles farther down the 
river. According to Dall these sedimentary rocks belong to 
_Cope’s “Idaho Lake,” and are ‘very likely middle or later 
pliocene. Both the unconsolidated character of the Nampa 
beds and the lower level at which they occur indicate a pleisto- 
cene age. They occur ina basin which has either been eroded 
out of Pliocene deposits synchronous with those at Glens 
Ferry, or in one formed by uneven elevations of land of which 
we have no definite record. The rapidity with which the 
deposits at Nampa were formed appears from their character. 
One of the beds of quicksand was 100 feet thick and two other 
40 and 30 respectively. For 70 miles below Nampa there are 
no superficial lava beds, while there at the Oregon line, the 
Snake River Valley becomes very much constricted, and con- 
tinues in a narrow gorge fora long distance. The situation 
furnishes just such conditions as would favor the rapid 
accumulation of fine sediment naturally brought down by 
such debacle from Lake Bonneville as is known to have taken 
place in pleistocene or glacial times. With respect to the 
age of the lava deposits it is also to be said that all observers, 
(espeeially Hayden and Russell) call frequent attention to 
outflows of lava in various parts of the Snake River Valley 
that are very recent—some of them not more than two or 
' three centuries old. We, therefore, are amply justified in 
connecting the Nampa figurine with deposits of glacial age. 


706 THE ICE AGE IN NORTH AMERICA. 


Concuusion. In the discoveries narrated above of man’s 
relation to the glacial epoch the study of every class of glacial. 
phenomena becomes invested with all the higher interest of 
historical research. Signal changes were introduced into the. 
- world’s history by the conditions which accompanied the 
Glacial epoch. In America as well as in Kurope this advent. 
of northern cold greatly disturbed the conditions of animal 
life, and, we may well suppose, directly led to the extine- 
tion of many animal species. In North America the camel, 
' the hippopotamus, the rhinoceros, the tapir, the mammoth, 
the horse, the mastodon, were abundant at the opening of 
the Quaternary age. Their complete extermination is one 
of the most startling facts in geology. But, as Darwin has 
so well shown, the effects of a glacial advance are by no 
means limited to the region directly reached by the ice. In 
pushing southward the plants and animals of the northern 
part of the continent, the struggle for life in the more 
crowded quarters of the decreasing congenial portions of the 
country became more and more intense, and thus doubtless 
was brought about much of the extinction of species which 
the geologists have to record as having taken place in the 
early part of the Quaternary period. The evidences of. 
man’s existence in North America before the close of the 
Glacial period would indicate that he too shared in the sharp 
struggle which ensued with the new and rapidly changing 
conditions of that time. Did he also, like so many of his 
companions among the larger animals, share in this extine- 
tion? The sharpness of the transition from the paleolithie 
to the neolithic type of implements, as we pass out from the 
Trenton gravel into the shallow soil above it, would seem to 
indicate an absolute distinction between the two succeeding 
races. But even so, whether the first became extinct from 
natural causes, and the other simply came in later as colonist, 
or whether the latter as conqueror exterminated the first, 
may always remain a doubtful question. It is possible that 
the Eskimo is the lineal descendant of preglacial man in 
America, and the conditions of life with which the Eskimo 


MAN AND THE LAVA BEDS. © 707 


_is so passionately in love would seém to resemble closely 
those which evidently surrounded paleolithic man in New 
Jersey, Ohio, Indiana, and Minnesota. But, on the other 
hand, such human remains as we have from the Trenton 
gravel are regarded by Professor Putnam as belonging to a 
race distinct in type from the Eskimo. 

A closing remark is in place with reference to the date 
of man’s appearance in America. In the first place it should 
be observed that, to say man was here before the close of 
the Glacial period only fixes a minimum point as to his an- 
tiquity. How long he may have been here previous to that 
time must be determined by other considerations. Secondly, 
with our present knowledge of glacial phenomena, the date 
of the close of the Glacial period is regarded as much more 
modern than it was a few years ago. Sir Charles Lyell’s 
estimate of thirty-five thousand years as the age of the Niag- 
ara gorge, which is one of the best measures of post-glacial 
time which has yet been studied, is greatly reduced by what 
we now know of the rate at which erosion is proceeding at 
the falls. Ten thousand years is now regarded as a liberal 
allowance for the age of that gorge. But, finally, the term 
“close of the Glacial period ” is itself a very indefinite ex- 
pression. The Glacial period was a great while in closing. 
The erosion of the Niagara gorge began at a time long sub- 
sequent to the deposit of the gravel at Trenton and at Madi- 
sonville. Between those two events time enough must have 
elapsed for the ice-front to have receded a hundred miles or * 
more, or all the distance from New York to Albany; since 
only at that stage of retreat would the valley of the Mohawk 
have been freed from ice so as to allow the Niagara River to 
begin its work. The deposits at Trenton, Madisonville, and 
Medora, took place while the ice-sheet still lingered in the 
southern water-shed of New York and Ohio. When, there- 
fore, the age of the movnd-builders of Ohio is reckoned by 
centuries, that of the glacial man who chipped these palzo- 
lithic implements must be reckoned by thousands of years. 

As is evident from the description of Mr. Upham, the 


708 THE ICE AGE IN NORTH AMERICA. 


gravel at Little Falls, Minn., is considerably more recent than 
- that in the more southern localities, since the gravel in Min- ) 
nesota could have been deposited only when the ice-front had 
retreated some hundreds of miles from its farthest extension, 
while the first-named deposits occur near the very margin of 
the glaciated area. 

Most of those who have taken pains to read the preceding 
pages through from the beginning have doubtless been sur- 
prised at the wide range of questions involved in the subject 
under discussion. ‘The movement of ice itself brings up for 
consideration one of the most singular and obscure of physical 
problems. A wide field of investigation is still open to the 
physicist in determining how it is that brittleness and mo- 
bility can so unite in one substance as to produce the phe- 
nomena of motion observed in living glaciers. The majesty 
of the ice-movement, as brought to light in the study of the 
glaciated area in North America, is equaled only in the 
movement of the forces of astronomy, or in that of those 
which have elevated the mountain-ranges on the surface of 
the earth. Almost every human interest in the northern 
part of the United States and in British America is likewise 
seen to be profoundly affected by the ice-movement which 
we have been permitted to study. During the great Ice age 
the old lines of drainage were obliterated, and new lines 
established, crooked places were made straight, and rough 
places plain. The change in the river-courses produced by 
the obstruction of glacial deposits has given rise to the innu- 
merable waterfalls where have grown up the flourishing 
manufacturing and commercial centers of New England and 
the interior. The Great Lakes are in the main the result of 
similar glacial obstruction. The vast internal commerce of 
the lake region avails itself of slack-water navigation result- 
ing from the ice-movements of the Glacial age. The imnu- 
merable lakes of smaller size which adorn the surface of the 
northern part of the continent are also the result of glacial 
action. The anomalous distribution of insects and plants can 
likewise, in many cases, be traced to the same cause. The 


MAN AND THE LAVA BEDS. 709 


arctic butterflies and the Alpine flowers upon the summit of 
Mount Washington, as well as the gigantic forests of Califor- 
nia and some of their more distant relatives on the Atlantic — 
coast, were fugitives from the arctic regions in glacial times, 
who have since become naturalized citizens of the lower lati- 
tudes. And, finally, man himself is connected with the clos- 
ing centuries of the Glacial period in the United States. 
American scholars who are ambitious to carry on archxo- 
logical investigations need no longer go to the valley of the 
Euphrates or the Nile, or to the languages of central Asia, 
to find the oldest relics of man in the world, or the surest 
means of determining the greatness of his antiquity. A 
boundless, comparatively unworked, most promising and most 
interesting field lies before the American investigator in the 
glacial problems of his own country. Nowhere else in the 
world did the ice of the Glacial period deploy out upon so 
wide a margin of dry land, and leave so inviting and easy a 
field of study. Every river rising within the glacial boundary 
and emerging from the glaciated region presents a problem 
worthy of the life-long attention of any investigator. Every 
glacial waterfall and every glacial lake holds out the possibil- 
ity of yielding up an important clew to chronological ques- 
tions of absorbing interest. The ingenuity of Professor Asa, 
Gray and others in tracing out the effects of the great Ice 
age upon the distribution of plants and animals, has only 
introduced us to subjects which need yet to be worked out 
in endless detail. The object of the present treatise will be 
largely accomplished if it serves to stimulate and guide the 
host of local investigators which the subject is sure to in- 
terest. 


BIBLIOGRAPHY 


W. R. Abercrombie: ‘‘Crossing the Valdez Glacier, Alaska, at Bates 
Bay,” ‘‘American Geologist,’’ vol. xxiv, pp. 349-354. 

W. C. Alden: ‘‘The Chicago Folio,’”’ “Geol. Atlas of the United 
States,’ U. S. Geological Survey, Folio 81; ‘Delevan Lobe of the 
Lake Michigan Glacier of the Wisconsin Stage of Glaciation and 
Associated Phenomena,” “Professional Papers of U. S. Geological 
Survey,” No. 34; “The Drumlins of Southeastern Wisconsin,’ 
“Bulletin of U. S. Geological Survey,’’ No. 273. 

Ralph Arnold: “The Tertiary and Quaternary Pectens of Califor- 
nia,’’ ‘‘ Professional Papers, U. S. Geological Survey,’’ No. 47. 

W. W. Atwood: ‘‘Glaciation of San Francisco Mountain, Arizona,”’ 
“Journal of Geology,” vol xiii, pp. 276-279; “‘Glaciation of the 
Uinta and Wasatch Mountains, Utah,” ‘‘ Bulletin of U. S. Geologi- 
eal Survey,’’ No. 61; ‘‘The Glaciation of the Uinta Mountains,”’’ 
“Journal of Geology,”’ vol. xv, pp. 790-804. 

H. Foster Bain: ‘‘Preglacial Elevation of Iowa,’ ‘‘ Proceedings, 
the lowa Academy of Science,” vol. ii, pp. 23-26; ‘‘Interloessal Till 
near Sioux City, Iowa,”’ ibid., pp. 20-23; ‘‘ The Aftonian and Pre-Kan- 
san Depositsin Southwestern Iowa,” ibid., vol. v, pp. 86-101; ‘‘ Notes 
on the Drift of Northwestern Iowa,’ ‘‘ American Geologist,’ vol. xxiii, 
pp. 168-176; “‘Relation of the Wisconsin and Kansas Drift Sheets in 
Central Iowa, and Related Phenomena,”’ “ Iowa Geological Survey,”’ 
vol. vi, pp. 433-476. 

E. S. Balch: ‘‘Glaciers or Freezing Caverns,’’ Phila., Allen, Lane 
& Scott, 1900. 

S. P. Baldwin: ‘‘Recent Changes in Muir Glacier,’’ ‘‘ American 
Geologist,’ June, 1893; ‘Pleistocene History of the Champlain 
Valley,” ibid.. March, 1894. 

H. M. Bannister: ‘‘The Drift and Geologic Time,’’ “‘Journal of 
Geology,’’ vol. v, pp. 730-743. ’ 

E. H. Barbour: “‘ Ancient Inhabitants of Nebraska,’’ ‘‘ Records of 
the Past,’’ vol. vi, pp. 40-46; also ‘“‘ Nebraska Geological Survey,”’ 
vol. ii, pt. 5, pp. 318-327, pt. 6, pp. 331-348, “Glacial Grooves and 
Strie in Southeastern Nebraska,’’ “Journal of Geology,’’ vol. 
viii, pp. 309-312. 


712 THE ICE AGE IN NORTH AMERICA. 


G. H. Barton: “Glacial Origin of Channels on Drumlins,”’ “ Bulle- 
tin of the Geological Society of America,”’ vol. vi, pp. 8-12; “‘Glacial 
Observations in the Umanak District, Greenland,’’ ‘Technological 
Quarterly,’ vol. x, pp. 213-244. 

H. Basedow and J. D. Iliff: ‘‘On a Formation known as ‘Glacial 
Beds of Cambrian Age’ in South Australia,’”’ ‘‘Quarterly Journal of 
the Geological Society of London,” vol. lxiv, pp. 260-263. 

H. Bashore: ‘The Harrisburg Terraces,’’ ‘‘American Journal of 
Science,’’ February, 1894; ‘“‘Notes on Glacial Gravels in the Lower 
Susquehanna Valley,’’ ibid., April, 1896. 

E. S. Bastin: ‘‘A Permian Glacial Invasion (in the Transvaal),”’ 
.““American Geologist,’’ vol. xxix, pp. 169-170. 

C. S. Beachler: ‘‘An Abandoned Pleistocene River Channel’’ 
{in Decatur County, Ind.], ‘Journal of Geology,”’ vol. ii, pp. 62-65. 
_ J.M. Bell: ‘Douglass Glacier and its Neighborhood,” ‘“‘Geograph- 
ical Journal,’ August, 1908; ‘‘Heart of the Southern Alps, New 
Zealand,” ibid., August, 1907. 

Robert Bell: ‘‘ Proofs of the Rising of the Land around Hudson Bay,”’ 
‘‘ American Journal of Science,’’ March, 1896; ‘‘On Glacial Phenomena 
in Canada,’ ‘‘Bulletin of the Geological Society of America,’’ vol. 
i, pp. 237-310; ‘‘A Great Preglacial River in Northern Canada,” 
‘‘Proceedings of the Royal Society of Canada,’’ May 15, 1895; ‘‘The 
.Labrador Peninsula,’’ ‘‘Scottish Geographical Magazine,”’ July, 1895. 
‘“‘The Geological History of Lake Superior,’”’ “Can. Inst. Trans.,”’ 
vol. vi, pp. 45-60. 

C. P. Berkey: ‘Laminated Interglacial Clays of Grantsburg, Wis.,’’ 
“Journal of Geology,’’ vol. xiii, pp. 35-44. 


S. W. Beyer: ‘Buried Loess in Story County [Iowa], “Pro-— 


ceedings of the Iowa Academy of Science,” vol. vi, pp. 117-121; ‘“Evi- 
dence of a Sub-Aftonian Till Sheet in Northeastern Iowa,”’’ ibid., 
vol. iv, pp. 58-62. 

Eliot Blackwelder: ‘‘Glacial Features of the Alaskan Coast between 
Yakutat Bay and the Alsek River,’’ ‘‘ Journal of Geology,’ vol. xv. 
pp. 415-483; ‘“On the Probable Glacial Origin of Certain Folded 
Slates in Southern Alaska,’’ ibid., vol. xv, pp. 11-14. 

W. P. Blake: ‘Glacial Erosion and the Origin of the Yosemite 
Valley,’’ ‘‘Transactions of the American Institute of Mining Engi- 
neers,’ vol. xxix, pp. 823-835; ‘‘Remains of a Species of Bosin the 
Quaternary of Arizona,’ ‘‘ American Geologist,’’ vol. xxii, pp. 65-72. 

W. S. Blatchley: ‘‘Gold and Diamonds in Indiana,” ‘‘ Indiana 
Department of Geology and Natural Resources,’’ 27th Annual Report, 
pp. 11-47. 

J. A. Bownocker: ‘‘History of the Little Miami River [Ohio],’’ 
‘Ohio State Academy of Sciences,’’ Special Papers, no. iii, pp. 32-45. 

J. H. Bretz: ‘‘Glacial Lakes of Puget Sound,’’ ‘‘ Journal of 
Geology,” vol. xviii, pp. 448-458. 


BIBLIOGRAPHY. 713 


A. P. Brigham: ‘‘ Drift Bowlders between the Mohawk and Susque- 
hanna Rivers,’’ ‘‘ American Journal of Science,’’ March, 1895; ‘‘The 
Finger Lakes of New York,”’ “‘ Bulletin of the American Geographical 
Society,’’ 1893; ‘‘Rivers and the Evolution of Geographic Forms,”’ 
ibid., 1892; ‘‘A Chapter in Glacial History, with Illustrative Notes 
from Central New York,’”’ ‘‘Transactions of the Oneida Historical 
Society,’ 1892; ‘‘Glacial Flood Deposits in Chenango Valley’’ 
[New York], ‘“Bulletin of the Geological Society of America,”’ vol. viii, 
pp. 17-30; ‘‘Topography and Glacial Deposits of Mohawk Valley,” 
ibid., vol. ix, pp. 183-210. 

R. W. Brock: “Boundary Creek District, British Columbia,’’ 
“Canada Geological Survey,’’ Summary Rept., 1901, pp. 49-67, 
[Glaciation, p. 57]. 

A. H. Brooks: “Sketch of the Geology of Southeastern Alaska,’’ 
“U.S. Geological Survey, Professional Paper,’’ no. 1, pp. 31-33; 
and others: ‘‘Reconnaissances in the Cape Nome and Norton Bay 
Regions, Alaska, in 1900,” “‘U. S. 56th Congress, 2d Sess., House 
Document,’’ No. 547. [Surface geology, pp. 41-47]. . 

E. R. Buckley: ‘‘Ice Ramparts,”’ ““Wis. Acad. Sci. Arts and Letters,’’ 
Trans., vol. xiii, pt. 1, pp. 141-157. 

E. P. Buffett: ‘‘Some Glacial Conditions and Recent Changes on 
Long Island,”’ ‘‘ Journal of Geography,’’ February, 1903. 

E.M. Burwash: ‘‘ Geology of the Nipissing-Algonia Line [Ontario],”’ 
“Ontario Bureau of Mines,”’ 6th An. Rept., pp. 167-184. 

F.H.H. Calhoun: ‘‘The Montana Lobe of the Keewatin Ice Sheet, s 
“U.S. Geological Survey, Professional Papers,’’ No. 50. 

Samuel Calvin: ‘‘The Buchanan Gravels: An Interglacial Deposit 
in Buchanan County, Iowa,’’ ‘‘American Geologist,’’ February, 
1896; ‘“‘Geology of Jones County,’’ ‘‘Iowa Geological Survey,’”’ vol. 
v, (Annual Report, 1895), pp. 33-112; ‘‘The Aftonian Gravels and 
their Relations to the Drift Sheets in the Region about Afton Junc- 
tion and Thayer [Iowa],’’ ‘‘ Proceedings of the Davenport Academy 
of Sciences,”’ vol. x, pp. 18-31; ‘‘Iowan Drift,’’ ‘‘ Bulletin of the Geo- 
logical Society of America,”’ vol. x, pp. 107-120; ‘‘A Notable Ride 
from Driftless Area to Iowan Drift,’’ ‘‘American Geologist,’’ vol. 
Xxiv, pp. 372-376; “‘Present Phase of the Pleistocene Problem in 
Iowa,”’ “‘Bulletin of the Geological Society of America,’’ vol. xx, 
pp. 133-152. 

Frank Carney: ‘‘ Glacial Erosion in Longitudinal Valleys,’ ‘‘ Journal 
of Geology,”’ vol. xv, pp. 722-730; ‘‘Possible Overflow Channel of 
Ponded Waters Antedating the Recession of Wisconsin Ice,’’ ‘‘ Ameri- 
can Journal of Science,’’ March, 1908; ‘‘Pre-Wisconsin Drift in the 
Finger Lake Region of New York,” ‘‘Journal of Geology,” vol. xv, 
pp. 571-585; ‘“‘A Type Case in Diversion of Drainage,’’ ‘‘ Journal of 
Geography,”’ March, 1903; ‘‘Valley Dependencies of the Scioto 
Illinoisan Lobe in Licking County, Ohio,” “Journal of Geology,’? 


714 THE ICE AGE IN NORTH AMERICA. 


vol. xv, pp. 488-495; ‘‘Wave-cut Terraces in Kueka Valley, Older 
than the Recession Stage of Wisconsin Ice,”’ ‘‘American Journal of 
Science,’’ May, 1907. 

Austin Cary: ‘‘Geological Facts noted on Grand River, Labrador,”’ 
“‘American Journal of Science,’’ November, 1891. 

E. C. Case: ‘Experiments in Ice Motion,” ‘‘Journal of Geology,” 
vol. iii, pp. 918-934. 

R. Chalmers: ‘‘Glacial Lake St. Lawrence of Professor Warren 
Upham,”’ ‘American Journal of Science,’’ April, 1895; ‘‘ Pleistocene 
Marine Shore Lines on Southern Side of the St. Lawrence Valley,” 
ibid., April, 1896; ‘‘ Height of the Bay of Fundy Coast in the Glacial 
Period relative to Sea-Level, as evidenced by Marine Fossils in the 
Bowlder-clay at St. John, N. B.,”’ ‘‘ Bulletin of the Geological Society 
of America,”’ vol. iv, pp. 361-370; ‘‘Geomorphic Origin and Develop- 
ment of the Raised Shore Lines of the St. Lawrence Valley and Great 
Lakes,’”’ “‘ American Journal of Science,’’ September, 1904; “‘The Glaci- 
ation of Mount Orford, P. Q.’’ [Canada], “Ottawa Naturalist,” vol. xix, 
pp. 52-55; ‘‘Preglacial Decay of Rocks in Eastern Canada,’”’ “‘ Ameri- 
can Journal of Science,’’ April, 1898. 

R. T. Chamberlin: ‘‘The Glacial Features of the St. Croix Dalles 
Region,’’ ‘‘ Journal of Geology,” vol. xiii, pp. 238-256. 

T. C. Chamberlin: ‘‘On the Relationship of the Pleistocene to the 
Pre-pleistocene Formation of the Mississippi Basin South of the Limit 
of Glaciation,’ ‘‘American Journal of Science,’’ May, 1891; ‘‘The 
Diversity of the Glacial Period,’’ ibid., March, 1893; ‘‘ Further 
Studies of the Drainage Features of the Upper Ohio Basin,” ibid., 
April, 1894; ‘‘Some Additional Evidences bearing on the Interval 
between the Glacial Epochs,”’ ‘‘ Bulletin of the Geological Society of 
America,’’ vol. i, pp. 469-480; ‘‘ Recent Glacial Studiesin Greenland,” 
ibid., vol. vi, pp. 199-220; ‘‘The Nature of the Englacial Drift of the 
Mississippi Basin,”’ ‘‘ Journal of Geology,”’ vol. i, pp. 47-60; ‘‘The 
Horizon of Drumlin, Osar, and Kame Formation,” ibid., pp. 255-267; 
“‘Glacial Studies in Greenland,” ibid., vol. ii, pp. 649-666, 768-788; 
vol. iii, pp. 61-69, 198-218, 469-480, 565-582, 668-681, 833-843; ‘The 
Classification of American Glacial Deposits,’’ ibid., vol. iii, pp. 
270-277 ; review of Wright’s ‘‘ New Evidence on Glacial Manin Ohio,”’ 
ibid., vol. iv, pp. 107, 219-221; ‘‘An Attempt to Frame a Working 
Hypothesis of the Cause of Glacial Periods on an Atmospheric Basis,”’ 
ibid., vol. vii, pp. 545-584, 667-685, 751-787; ‘A Contribution to the 
Theory of Glacial Motion,’’ Decennial Publications of University of 
Chicago,’’ 1st ser., vol. ix, pp. 193-206; ‘‘The Geologic Relations of 
the Human Relics of Lansing, Kansas,’’ “‘Journal of Geology,’’ vol. 
x, pp. 745-779 ; ‘Glacial Studiesin Greenland,”’ ‘‘ Journal of Geology,” 
vol. v, pp. 229-240; ‘‘Supplementary Hypothesis respecting the Ori- 
gin of the Loess of the Mississippi Valley,” ‘‘Journal of Geology,’ 
vol. v, pp. 795-802. 


BIBLIOGRAPHY. 715 


L. W. Chaney: “‘Glacier on Montana Rockies,’’ ‘‘Science,’? Decem- 
ber 13, 1895; ‘‘Glacial Exploration in the Montana Rockies,”’ “ Inter- 
national Geographical Congress, 8th Report,’’ pp. 403-496. 

F. G. Clapp: ‘‘Geological History of the Charles River,’’ [Massa- 
chusetts], ‘‘Technology Quarterly,” vol. xiv, pp. 171-201; ‘‘ Relations 
of Gravel Depositsin the Northern Part of Glacial Lake Charles, 
Massachusetts,”’ ‘‘Journal of Geology,’’ vol. xii, pp. 198-214. 

W. Blair Clark: ‘‘ Drainage Modifications in Knox, Licking and 
Coshocton Counties’’ [Ohio], ‘‘Bulletin of the Scientific Laboratories 
of Denison University,’’ vol. xii, pp. 1-16. 

E. W. Claypole: ‘Glacial Notes from the Planet Mars,’’ ‘“‘ American 
Geologist,’’ August, 1895; ‘‘ Professor G. F. Wright and his Crities,’’ 
“Popular Science Monthly,’’ April, 1893; ‘‘Glacial ‘Theories—Cos- 
mical and Terrestrial,’’ ‘‘ American Geologist,’’ vol. xxii, pp. 310-315. 

A. P. Coleman: “ Interglacial Fossils from the Don Valley, Toronto,” 
“American Geologist,’? February, 1894; ‘‘Glacial and Interglacial 
Deposits near Toronto,”’ ‘‘ Journal of Geology,’’ vol. 111, pp. 622-645; 
“Duration of the Toronto Interglacial Period,’ ‘‘American Geolo- 
gist,’’ vol. xxix, pp. 71-79; ‘‘Glacial and Interglacial Beds near 
Toronto,” ‘‘ Journal of Geology,’ vol. ix, pp. 285-310. ‘“‘Glacial and 
Interglacial Deposits at Toronto [Canada],’’ ‘‘British Association 
for the Advancement of Science,’ Report, 1897, pp. 650-651; “‘ Glacial 
Lakes and Pleistocene Changes in the St. Lawrence Valley,” ‘‘ Inter- 
national Geographical Congress,’’ 8th Report, pp. 480-486; ‘‘Glacial 
Periods and their Bearing on Geological Theories,” ‘‘ Bulletin of the 
Geological Society of America,’’ vol. xix, pp. 347-366; ‘‘Lake Iro- 
quois and its Predecessors at Toronto,” ibid., vol. x, pp. 165-176; 
“‘Lower Huronian Ice Age,” ‘‘ American Journal of Science,’’ March, 
1907; ‘‘The Lower Huronian Ice Age,’ ‘Journal of Geology,’’ vol. 
xvi, pp. 149-158; ‘‘On the Pleistocene near Toronto [Canada],’’ 
‘‘British Association for the Advancement of Science,’’ Report, 1900, 
pp. 328-334; ‘‘Relation of Changes of Levels to Interglacial Periods, 
“Geological Magazine,’’ Dec. 4, vol. ix, pp. 59-62. 

G. H. Colton: ‘‘A Possible Cause of Osars,’’? ‘‘Ohio Naturalist,” 
vol. ii, pp. 257. 

F. M. Comstock: ‘“A Small Esker in Western New York,’’ ‘“‘ Ameri- 
can Geologist,’’ vol. xxxii, pp. 12-13. 

W. M. Conway: ‘‘ An Exploration in 1897 of some of the Glaciers of 
Spitsbergen,”’ ‘Geographical Journal,’’ August, 1898. 

W. O. Crosby: ‘Distribution and Probable Age of the Fossil 
Shells in the Drumlins of the Boston Basin,’”’ ‘‘American Journal of 
Science,’’ December, 1894; ’‘ Englacial Drift,’’ ‘‘ American Geologist,” 
April, 1896; ‘‘Composition of Till or Boulder Clay,’’ ‘‘ Proceedings of 
the Boston Society of Natural History,’ vol. xxv, pp. 115-140; ‘‘Geo- 
logical History of the Nashua Valley, N. H., during the Tertiary and 
Quaternary Pericds,’’ ‘Technology Quarterly,” vol. xii, pp. 288-324, 


716 THE ICE AGE IN NORTH AMERICA. 


“Origin of Eskers,’’ ‘“‘ American Geologist,’’ vol. xxx, pp. 1-39; ‘‘Struc- 
ture and Composition of the Delta Plains formed during the Clinton 
Stage in the Glacial Lake of the Nashua Valley,” ‘‘Technology 
Quarterly,’’ vol. xvi, pp. 240-254, vol. xvii, pp. 37-75. 

F. Cross. ‘The Buried Valley of Wyoming [Pennsylvania],’’ “‘Wyom- 
ing Hist. and Geol. Soc., Proc. and Coll., vol. viii, pp. 42-44. 

G. EB. Culver: “‘On a Little-Known Region of Northwestern Mon- 
tana,’’ “‘Transactions of the Wisconsin Academy of Science,’’ vol. 
viii, pp. 188-205; ‘“‘The Erosive Action of Ice,’’ ibid., vol. x, pp. 
339-366. 

P. W. Currie: ‘‘On the Ancient Drainage at Niagara Falls,” “Can. 
Inst., Trans.,’’ vol. vii, pp. 7-14. 

G. C. Curtis and J. B. Woodworth: ‘‘ Nantucket a Morainal Island,” 
‘Journal of Geology,’ vol. vii, pp. 226-236. 

H. P. Cushing: ‘‘ Notes on the Muir Glacier Region, Alaska, and its 
Geology,”’ ‘‘American Geologist,’’ October, 1891. 

R. A. Daley: ‘Geology of the Region Adjoining the Western Part 
of the International Boundary,” ‘‘Canada Geol. Survey,’’ Summary 
Rept., 1901, pp. 37-49. [Glaciation, pp. 41-45]. } 

J. D. Dana: ‘‘On New England and the Upper Mississippi Basin 
in the Glacial Period,’’ ‘‘American Journal of Science,’’ November, 
1893; ‘‘Manual of Geology,” fourth edition, 1895, pp. 943-995. 

George Davidson: ‘‘The Glaciers of Alaska that are shown on Rus- 
sian Charts or mentioned in Older Narratives,’’ ““Geog. Soc. of Pac., 
Trans. and Proc.,’’ 2d. ser., vol. iii, pp. 1-98. 

W. M. Davis: “Structure and Origin of Glacial Sand Plains,”’ 
‘‘Bulletin of the Geological Society of America,”’ vol. i, pp. 195-202; 
‘‘Subglacial Origin of Certain Eskers,”’ ‘‘Proceedings of the Boston 
Society of Natural History,’’ May 18, 1892; ‘‘Glacial Origin of Lakes,”’ 
‘‘Science,’’ June 14,1895; ‘Glacial Lakes of Western New York,”’’ ibid., 
July 5, 1895; ‘‘Causes of Permo-—Carboniferous Glaciation, “Journal 
of Geology,’’ vol. xvi, pp. 79-82; ‘‘Glacial Erosion in France, Switz- 
erland, and Norway,’ “‘Proceedings, Boston Society of Natural 
History,’”’ vol. xxix, pp. 273-322; ‘‘Glacial Erosion in the Valley of 
the Ticino,”’ ‘‘ Appalachia,’’ vol. ix, pp. 136-155; ‘‘Glacial Erosion in 
the Sawatch Range, Colo.,”’ ibid., vol. x. pp. 392-404; ““Glaciation of 
the Sawatch Range, Colorado,” ‘“‘Bulletin of the Museum of Com- 
parative Zodlogy of Harvard College,’”’ vol. xlix, pp. 1-11; ‘River 
Terraces in New England,”’ ibid., vol. xxxviii, pp. 281-346; ‘‘ Terraces 
of the Westfield River, Mass.,’’ ‘‘American Journal of Science,” 
August, 1902. 

G. M. Dawson: ‘‘Glacial Deposits of Southwestern Alberta in the 
Vicinity of the Rocky Mountains,”’ ‘Bulletin of Geological Society 
of America,’’ vol. vii, pp. 31-66; ‘‘ Notes on the Occurrence of Mam- 
moth Remains in the Yukon District of Canada and in Alaska,” 
‘“‘Quarterly Journal of the Geological Society,” ‘‘February, 1894; 


BIBLIOGRAPHY. 717 


‘“Notes on the Glacial Deposits of Southwestern Alberta,’’ “‘ Journal 
of Geology,”’ vol. iii, pp. 507-511; ‘‘ Are the Bowlder Clays of the Great 
Plains Marine?” ‘“‘Journal of Geology,” vol. v, pp. 257-262. 

J. William Dawson: “On the Pleistocene Flora of Canada,’’ 
“Bulletin of the Geologica! Society of America,’’ vol. i, pp. 311-334; 
“Canadian Ice Age: Being Notes on the Pleistocene Geology of 
Canada, with Especial Reference to the Life of the Period and its 
Climatal Conditions,”’ 1893. 

W.L. Dawson: “‘Glacial Phenomena in Okanogan County, Washing- 
ton,” ‘‘ American Geologist,’’ vol. xxii, pp. 203-217. 

G. De Geer: ‘‘On Pleistocene Changes of Level in Eastern North 
America,’’ ‘‘ Proceedings of the Boston Society of Natural History,”’ 
May 18, 1892. 

H. N. Dickson: ‘‘Mean Temperature of the Atmosphere and the 
Causes of Glacial Periods,’’ ‘‘ Geographical Journal,’’ November, 1901. 

J.S. Diller: ‘Glaciation of Mount Mazama,”’ “U.S. Geol. Survey, 
Professional Paper,’’ No. iii, pp. 41-44. 

D. B. Dowling: “Physical Geography of Red River Valley,’’ 
“Ottawa Naturalist,’ vol. xv, pp. 115-120: ‘“‘West Shore and Islands 
Lake Winnepeg,’’ ‘‘Canada Geological Survey,’ An. Rept., vol. 
xi, pp. 93-100. 

P. Dresser: ‘‘Note on the Glaciation of Mount Orford, P. Q.,’’ 
“Canadian Record of Science,’’ vol. viii, pp. 223-225. 

J. A. Drushel, ‘‘Glacial Drift under the St. Louis Loess, ‘‘ Journal 
of Geology, vol. xvi, pp. 493-498. 

C. R. Dryer: ‘‘Certain Peculiar Eskers and Esker Lakes of North- 
eastern Indiana,”’ ‘‘Journal of Geology,”’ vol. ix, pp. 123-129; “‘ Fin- 
ger Lake Region of Western New York,” “ Bulletin of the Geological 
Society of America,’ vol. xv, pp. 449-460. 

R. L. Dunn: “The Country of the Klondike [Alaska],’’ “‘ Mining and 
Scientific Press,’’ vol. lxxvii, pp. 400, 425-426, 449. 

J.W. Eggleston: ‘Glacial Remains near Woodstock, Connecticut,’’ 
‘American Journal of Science,’’ May, 1902. 

A. H. Elftman: “Geology of the Keweenawan Area in Northeast- 
ern Minnesota,’’ ‘‘American Geologist,’’ vol. xxi, pp. 90-109; ‘“‘The 
St. Croix River Valley [Minnesota—Wisconsin],”’ ibid. vol. xxii, pp. 
58-61. 

R. W. Elis: “Ancient Channels of the Ottawa River’ [Canada], 
“Ottawa Naturalist,’’ vol. xv, pp. 17-30. 

B. K. Emerson: “Geology of Old Hampshire County, Massachu- 
setts, comprising, Franklin Hampshire, and Hampden Counties,’’ 
“United States Geological Survey,’’ Monograph xxix. 

P.M. Emerson: ‘Glacial Topography in Central New Hampshire, 
“‘Appalachia,’’ vol. x, pp. 299-303. 

H. L. Fairchild: ‘“The Kame Moraine at Rochester, N. Y.,” 
‘American Geologist,’’ July, 1895; ‘‘Glacial Lakes of Western New 


718 THE ICE AGE IN NORTH AMERICA. 


York,’’ “Bulletin of the Geological Society of America,’’ vol. vi, 
pp. 353-374; ‘‘ Lake Newberry the Probable Successor of Lake Warren,’’ 
ibid., pp. 462-466; ‘‘ Kame Areas in Western New York South of Iron- 
dequoit and Sodus Bays,” ‘“‘Journal of Geology,’’ vol. iv, pp. 129- 
159; ‘‘The Length of Geologic Time,”’ ‘‘ Proceedings of the Rochester 
Academy of Science,”’ April 23, 1894; ‘‘Glacial Geology of Western 
New York,” ‘Geological Magazine,’”’ Dec. 4, vol. iv, pp. 529-537; 
‘“‘Glacial Geology in America,’”’ ‘‘American Geologist,’ vol. xxii, 
pp. 154-189; ‘Glacial Lakes Newberry, Warren and Dana, in Central 
New York.”’ ‘American Journal of Science,’’ April, 1899; “Glacial 
Waters from Oneida to Little Falls,’ ‘‘New York State Museum,”’ 
56th An. Rep., vol. 1; ‘‘Glacial Waters in the Finger Lakes Region of 
~ New York,’”’ ‘Bulletin of the Geological Society of America,’’ vol. 
x, pp. 27-68; ‘‘Ice Erosion Theory a Fallacy,” ibid., vol. xvi, pp. 13- 
74; ‘Kettles in Glacial Lake Deltas,” ‘‘Journal of Geology,’’ vol. 
vi, pp. 589-596; ‘‘Lake Warren Shorelines in Western New York and 
the Geneva Beach,”’ ‘‘ Bulletin of the Geological Society of America,”’ 
vol. viii, pp. 269-284; ‘‘Latest and Lowest Pre-Iroquois Channels 
between Syracuse and Rome,” ‘‘New York State Museum,”’ 55th An. 
Rept., pp. r31-r47; ‘Pleistocene Features in the Syracuse Region,”’ 
“American Geologist,’’ vol. xxxvi, pp. 135-141; ‘‘ Pleistocene Gedlogy 
of Western New York,’ “‘20th Report of State Geologist,’’ 1900, 
pp. 103-139. 

N. M. Fennerman: ‘‘The Arapahoe Glacier in 1902,’’ “Journal of 
Geology,’ vol. x, pp. 839-851. 

'H. G. Ferguson: ‘‘Tertiary and Recent Glaciation of an Icelandic 
Valley,” “Journal of Geology,’’ vol. xiv, pp. 122-133. 

G. E. Finch: ‘Drift Section at Oelwein, Iowa,’’ ‘““‘Iowa Acad. Sci. 
Proceed.,’’ vol. iv, pp. 54-58. 

George Rinibe: ‘‘Granite Area of Barre, Vermont,” ‘“‘An. Rept. State 
Geologist,’’ 1902, pp. 46-45. ; 
T. J. Fitepatrick: ‘The Drift Section and the Glacial Striz in 
the Vicinity of Lamoni,”’ ‘““Iowa Acad. Sci. Proc.,’’ vol. v, pp. 105-106. 

Gerard Fowke: ‘‘Preglacial Drainage Conditions in the Vicinity of 
Cincinnati,’’ ‘‘Ohio State Academy of Science,’’ Special Papers, No. 
ili, pp. 68-75; “‘Pre-Glacial Drainage in the Vicinity of Cincinnati, 
its Relation to the Origin of the Modern Ohio River, and its Bearing 
upon the Question of the Southern Limits of the Ice Sheet,’’ “ Bulle- 
tin of the Scientific Laboratories of Denison University,’ vol. xi, 
pp. 1-10. ‘‘The Preglacial Drainage of Ohio—Introduction,”’ ‘‘Ohio 
State Academy of Sciences,’’ Special Papers, no. ili. pp. 5-9. 

C. D. Fox: ‘‘The Glaciers, Past and Present, in the South Island 
of New Zealand,” “‘Journal of Transactions of the Victoria Institute,”’ 
vol. xl. 

D. W. Freshfield: ‘‘Glaciers of Kangchenjunga,’’ ‘‘Geographical 
Journal,”’ April, 1902. 


BIBLIOGRAPHY. 719 


M. L. Fuller: “Champlain Submergence in the Narraganset Bay 
Region,” ‘‘ American Geologist,’’ vol. xxi, pp. 310-321; ‘‘General and 
Pleistocene Geology of the Ditney, Indiana Folio,’ ‘‘Geological 
Atlas of the United States,’’ “‘U. S. Geol. Survey”’ Folio, no. 84, p, 
1-7; “Geology of Fishers Island, New York,”’ “‘ Bulletin of the Geo- 
logical Seciety of America,’’ vol. xvi, pp. 367-390; ‘“‘Ice-Retreat in 
Glacial Lake Neponset andin Southeastern Massachusetts,”’ ‘‘ Jour- 
nal of Geology,” vol. xii, pp. 181-197; ‘“‘Probable Pre-Kansan and 
Iowan Deposits on Long Island,” “‘ American Geologist,’’ vol. xxxii, 
pp. 308-311; ‘‘Probable Representatives of Pre-Wisconsin Till in 
Southeastern Massachusetts,’’ ‘‘Journal of Geology,’’ vol. ix, pp. 
311-329; ‘‘Season and Time Elements in Sand-plain Formation,”’ 
ibid., vol. vii, pp. 452-462. 

A. Fulton: Results of Glacial Action in Canada,” ‘‘Technical 
World,’’ vol. viii, 144-150. 

F. M. Fultz: “Glacial Markingsin Southeastern Iowa,’ ‘‘ Proceed- 
ings of the Iowa Academy of Science, 1894;”’ ‘“‘ Extension of the IIli- 
nois Lobe of the Great Ice Sheet into Iowa,”’ ibid.; ‘‘Glacial Scorings 
in Des Moines County, Iowa,” “‘Second Annual Report of lowa Geo- 
logical Survey,” vol. iii, pp. 158-163; ‘‘Glaciers of America,”’ ‘“‘Sthool 
and Home Education,” vol. xxvii, pp. 169-177. 

Henry Gannett: ‘‘Lake Chelan and its Glacier [Washington],’’ 
““Mazama,”’ vol. ii, pp. 185-189. 

V. H. Gatty: ‘Glacial Aspect of Ben Nevis,” ‘‘Geographical Jour- 
nal,’’ May, 1906. 

James Geikie: ‘‘The Classification of European Glacial Deposits,”’ 
“Journal of Geology,” vol. iii, pp. 241-269; ‘‘The Last Great Baltic 
Glacier,” ibid., vol. v, pp. 325-339; ‘‘On the So-called ‘Postglacial 
Formations’ of Scotland,” ibid, vol. xiv, pp. 668-682. 

G. K. Gilbert: ‘‘Lake Basins created by Wind Erosion,” “Journal 
of Geology,”’ vol. iii, pp. 47-49; ‘‘ Alaska, Glaciers and Glaciation,”’ 
“Harriman Alaska Expedition,’’ vol. iii; ‘‘Bowlder-Pavement at Wil- 
son, N. Y.,’”’ ‘Journal of Geology,” vol. vi, pp. 771-775; ‘‘Crescentic 
Gouges on Glaciated Surfaces,”’ ‘‘ Bulletin of the Geological Society 
of America,”’ vol. xvii, pp.*303-316; “‘Glacial Sculpture in Western 
New York,” ibid., vol. x, pp. 121-130; ‘‘Moulin Work under Glaciers,”’ 
ibid., vol. xvii, pp. 317-320; ‘‘Rate of Recession of Niagara Falls,”’ 
accompanied by a report on the survey of the crest by W. C. Hall, 
“Bulletin of the United States Geological Survey,’’ No. 306; ““Recent 
Earth Movements in the Great Lakes Region,’’ ‘‘United States Geo- 
logical Survey,” 18th An. Report, pt. iii, pp. 595-647; ‘‘Summary 
History of Niagara Falls,’ ‘American Geologist, vol. xxvii, pp. 375- 
377; “Variations of Sierra Glaciers,’’ ‘‘Sierra Club Bulletin,” vol. v, 
pp. 20-25. ‘‘Glaciers of Alaska’’ [Review of G. K Gilbert’s ‘‘ Alaska; 
Glaciers and Glaciation’’], ‘“‘National Geographic Magazine,’ No- 
vember. 1904. 


720 | THE ICE AGE IN NORTH AMERICA, 


J. W. Goldthwait: ‘‘ Isobases of the Algonquin and Iroquois Beacheg 
and their Significance,’’ ‘“‘ Bulletin of the Geological Society of Amer- 
ica,’ vol. xxi, pp. 227-248; ‘‘A Reconstruction of Water Planes of 
the Extinct Glacial Lakes in the Lake Michigan Basin,’ “‘ Journal of 
Geology,’’ vol. xvi, pp. 459-476; ‘‘The Sand Plains of Glacial Lake 
Sudbury,’’ ‘‘ Bulletin of the Museum of Comparative Zodlogy of Har- 
vard College,’”’ vol. xiii, pp. 263-301. 

C. H. Gordon: ‘‘Buried River Channels in Southeastern Iowa,”’ 
‘‘Second Annual Report of the Iowa Geological Survey,’ vol. iii, 
pp. 237-256; ‘‘Notes on the Kalamazoo and Other Old Glacial Out- 
lets in Michigan,’’ ‘‘ Journal of Geology,’ vol. vi, pp. 477-482. 

R. W. Gorman: ‘‘Ice Cliffs on White River, Yukon Territory,” 
“‘National Geographic Magazine,’’ March, 1900. 

A. W. Grabau: ‘‘The Preglacial Channel of the Genesee River,”’ 
‘Proceedings of the Boston Society of Natural History,’’ May 16, 
1894; ‘‘Guide to the Geology and Paleontology of Niagara Falls and 
Vicinity,’ “Bulletin of the New York State Museum,”’ No. 45, 284 pp. ;. 
‘‘Lake Bouvé, an Extinct Glacial Lake in the Southern Part of the 
Boston Basin,’’ ‘‘Occasional Papers, Boston Society of Natural His- 
tory” IV, pt. ili, pp. 564-600. 

U.S. Grant: ‘ Lakes with two Outlets in Northeastern Minnesota,” 
‘‘American Geologist,’ vol. xix, pp. 407-411; ‘‘A Possible Driftless 
Area in Northeastern Minnesota,” ibid., vol. xxiv, pp. 377-381. 

W. M. Gregory: ‘‘The Alabaster Area [Michigan],’’ ‘‘Michigan 
Geological Survey,’’ vol. ix, pt. 2, pp. 60-77. . 

W. Griffith: ‘‘An Investigation of the Buried Valley of Wyoming 
[Pennsylvania]? ‘‘Proceedings and Collections of the Wyoming 
Historical and Geological Society,’’ vol. vi, pp. 27-36. 

F. P. Gulliver: ‘“The Newtonville [Mass.] Sand-Plain,’”’ “Journal 
of Geology,’’ vol. i, pp. 803-812. 

Ossian Guthrie: ‘“‘The Newly Discovered Moraines in Illinois: 
Their Relations to the Glacial Channels across the Chicago Divide,” 
“‘Proceedings of the Chicago Geological Society,’’ May 19, 1893. 

J.C. Gwillim: ‘Glaciation in the Atlin District, British Columbia,”’ 
“Journal of Geology,” vol. x, pp. 182-185: 

F. W. Harmer: “Origin of Certain Cafion-like Valleys associated 
with Lake-like Areas of Depression,’’ ‘‘ Quarterly Journal of the Geo- 
logical Soc. of London, vol. xiii, pp. 470-514. 

T. W. Harris: ‘“The Kames of the Oriskany Valley [N. Y.],” 
‘‘ American Geologist,’’ June, 1894. 

C. W. Hayes and A. H. Brooks: ‘‘Ice Cliffs on White River, Yukon 
Territory,’ ‘‘ National Geographic Magazine,’’ May, 1900. 

A. Heilprin: ‘‘The Glaciers of Greenland,’ “Popular Science 
Monthly,’’? November, 1894. 

. Junius Henderson: ‘‘ Arapahoe Glacier in 1903,’’ ‘‘ Journal of Geol- 
ogy,” vol. xii, pp. 30-33; ‘‘Arapahoe Glacier in 1905,’ ibid., vol: 


BIBLIOGRAPHY. 721 


xiii, pp. 556; ‘“‘ Extinct Glaciers of Colorado,’’ ‘‘Studies of the Univer- 
sity of Colorado,’’ vol. iii, pp. 39-44. 

O. H. Hershey: ‘“‘The Pleistocene Rock Gorges of Northwestern 
Illinois,’ ‘‘American Geologist,’’ November, 1893; ‘‘The Columbia 
Formation in Northwestern Illinois,’ ibid., January, 1895; ‘‘Age of 
the Kansan Drift Sheet,’’ ibid., vol. xxviii, pp. 20-25; ‘Ancient 
Alpine Glaciers of the Sierra Costa Mountains in California,’ “‘ Jour- 
nal of Geology,” vol. viii, pp. 42-57; ‘‘Certain River Terraces of the 
Klamath Region, California,’ “‘American Journal of Science,’’ Sep- 
tember, 1903; ‘‘Eskers Indicating Stages of Glacial Recession in the 
Kansan Epoch in Northern Illinois,’’ ‘American Geologist,’’ vol. 
xix, pp. 197-209, 237-253; ‘‘The Inferior Boundary of the Quater- 
nary Era,’’ ‘‘American Naturalist,’ vol. xxxi, pp. 104-114; ‘‘The 
Loess Formation of the Mississippi Valley,’’ ‘“‘Science,’’ n. s. vol. 
v, pp. 768-770; ‘‘Mode of Formation of Till as Illustrated by the 
Kansan Drift of Northern Illinois,’”’ ‘‘Journal of Geology,’’ vol. v, 
pp. 50-62; ‘‘The Quaternary of Southern California,” ‘‘ Bulletin of 
* the Department of Geology of the University of California,” vol. iii, 
‘pp. 1-30; ‘Relation between Certain River Terraces and the Glacial 
Series in Northwestern California,’ ‘‘ Journal of Geology,” vol. xi, 
pp. 431-458; ‘‘The River Terraces of the Orleans Basin, California,” 
“Bulletin of the Department of Geology of the University of Cali- 
fornia,’’ vol. iii, pp. 423-475; ‘‘Some Evidence of Two Glacial Stages 
in the Klamath Mountains in California,’ ‘‘ American Geologist,”’ 
vol. xxxi, pp. 139-156; ‘‘The Upland Loess of Missouri—its Mode of 
Formation,” ‘‘ American Geologist,’’ vol. xxv, pp. 369-374. 

R. R. Hice: ‘‘ Glacial Grooves at the Southern Margin of the Drift,’’ 
“Bulletin of the Geological Society of America,’’ vol. ii, pp. 457-464; 
“The Inner Gorge Terraces of the Upper Ohio and Beaver Rivers,”’ 
““ American Journal of Science,”’ February, 1895; ‘‘ Note on the Buried 
Drainage System of the Upper Ohio,” “‘Science,’’ September 29, 
1883; ‘‘The Clays of the Upper Ohio and Beaver River Region,” 
“Transactions of American Ceramic Society,”’ vol. vii, pt. 2; *f North- 
ward Flow of Ancient Beaver River,” ‘‘Bulletin of the Geological 
Society of America,’’ vol. xiv, pp. 297-304. 

William Hill: ‘On a Deep Channel of Drift at Hitchin (Hertford- 
shire),’’ ‘Quarterly Journal of the Geological Society of London,’ 
vol. lxiv, pp. 8-26. 

C. H. Hitchcock: ‘Divisions of the Ice Age in the United States 
and Canada,” “‘ American Geologist,’’ May, 1895; ‘‘Glaciation of the 
White Mountains, N. H.,”’ “Bulletin of the Geological Society of 
America,’ vol. v, pp. 35-37; ‘‘Terminal Moraines in New England,’’ 
““Proceedings of the A. A. A. §.’”’ vol. xli, pp. 173-175; ‘‘Champlain 
Glacial Epoch,”’ ‘‘Science,’’? September 6, 1895; ‘‘Ancient Glacial 
Action in Australasia,’’ ‘American Geologist,’’ vol. xxiii, pp. 252-257; 
“‘Eastern Lobe of the Ice Sheet,’ ibid., vol. xx, pp. 27-33; “‘Glacia- 


722 THE ICE AGE IN NORTH AMERICA. 


tion of the Green Mountain Range,”’ ‘‘ Vermont Geological Survey, 
Report of the State Geologist,’ iv, pp. 67-85; ‘‘ Glaciation of the Green 
Mountains,’’ Montpelier, Vt., Argus and Patriot Press 1904; ‘“ Inter- 
glacial Deposits in the Connecticut Valley,” ‘Bulletin of the Geo- 


logical Society of America,’ vol. xii, pp. 9-10; ‘‘ New Zealand in the 


Ice Age,”’ ‘‘ American Geologist,’”’ vol. xxvili, pp. 271-281; ‘‘The Story 
of Niagara,’’ ‘‘American Antiquarian,’’ vol. xxiii, pp. 1-24. 

W. H. Hobbs: “Emigrant Diamonds in America,’’ ‘Popular 
Science Monthly,”’ vol. lvi, pp. 73-83; ‘‘Instances of the Action of the 
Ice-sheet upon Slender Projecting Rock Masses,” ‘‘ American Journal 
of Science,’’? December, 1902. 

T. H. Holland: ‘‘Observations of Glacier Movements in the Hima- 
layas,’’ ‘‘Geographical Journal,’’ March, 1908. 

Arthur Hollick: ‘A Reconnaissance of the Elizabeth Islands’’ 
[Massachusetts], ‘‘Annals of the New York Acadeiay of Science,’’ 
vol. xiii, pp. 387-418. 

W. H. Holmes: “‘Vestiges of Early Man in Minnesota,”’ ‘‘ American 
Geologist,’ April, 1893; ‘‘Are there Traces of Glacial Man in the 
Trenton Gravels?’’ “ Journal of Geology,’’ vol. i, pp. 15-163; ‘‘Traces 
of Glacial Man in Ohio,” ibid., vol. i, pp. 147-163; ‘‘ Fossil Human 
Remains found near Lansing, Kansas,’’ ‘‘ American Anthropologist,’ 
n. s. vol. iv, pp. 743-752. 

T. C. Hopkins: ‘‘Glacial Climate,” “‘Proceedings of the Onandaga 
Academy of Science,’’ vol. i, pp. 74-81. 

Walter Howchin: ‘‘Glacial Beds of Cambrian Age in South Aus- 
tralia,’ “Quarterly Journal of the Geological Society of London,”’ 
vol. lxiv, pp. 234-263. 

G. D. Hubbard: “Ancient Finger Lakes in Ohio,’ ‘American 
Journal of Science,’’ March, 1908; ‘‘High Level Terraces in South- 
eastern Ohio,’’ ‘‘American Journal of Science,” February, 1908; 
“An Interglacial Valley in Illinois,’’ ‘‘ Journal of Geology,” vol. 
xli, pp. 152-160; ‘“‘On the Origin of Fiords,”’ ‘‘ Bulletin of the American 
Geographical Society,’”’ vol. xxxili, pp. 401-408. : 

E. Hull: “ Another Possible Cause of the Glacial Epoch,”’ “Journal 
of Transactions of the Victoria Institute,’’ vol. xxxi. 

Ellsworth Huntington: ‘‘Pangong: a Glacial Lake in the Tibetan 
Plateau,” ‘‘ Journal of Geology,’’ vol. xiv, pp. 599-617; ‘‘Some Char- 
acteristics of the Glacial Period in Non-Glaciated Regions,’’ ‘‘ Bulletin 
of the Geological Society of America,” vol. xviii, pp. 351-388; 
‘“‘Pulse of Asia,’’ 1907. 

J. E. Hyde: ‘‘Changes in the Drainage near Lancaster [Ohio],”’ 
“Ohio Naturalist,’’ vol. iv, pp. 149-157. 

T. F. Jamieson: ‘‘Glacial Period in Aberdeenshire and the Southern 
Border of the Moray Firth,’’ ‘‘Quarterly Journal of the Geological 
Society of London,” vol. Ixii, pp. 13-39. 

M.S. W. Jefferson: ‘‘The Postglacial Connecticut at Turners Falls, 
Mass.,’’ ‘‘Journal of Geology,’’ vol. vi, pp. 463-472. 


BIBLIOGRAPHY 723 


Mark Jefferson: ‘Glacial Erosion in the Northfiord,”’ ‘Bulletin 
of the Geological Society of America,”’ vol. xviii, pp. 413-426; ‘‘ Lateral 
Erosion on Some Michigan Rivers,’’ ‘Bulletin of the Geological 
Society of America,”’ vol. xviii, pp. 333-350. 

B. C. Jillson: ‘River Terraces in and near Pittsburg,’’ ‘‘ Proceed- 
ings of the Pittsburg Academy of Sciences and Arts,’’ December 8, 
1893. 

W. D. Johnson: ‘‘Grade Profile in Alpine Glacial Erosion,”’ ‘‘Sierra 
Club Bulletin,” vol. v, pp. 271-278; ‘“‘The Profile of Maturity in 
Alpine Glacial Erosion,’’ ‘‘ Journal of Geology,” vol. xii, pp. 569-578. 

F. O. Jones: ‘‘Glacial Rock Sliding,’’ ‘‘ Journal of Geology,’’ vol. 
xv, pp. 485-487. 

A. A. Julien: “Geology of Central Cape Cod,” ‘‘American Geol- 
ogist,’’ vol. xxvii, p. 44. 

K. Keilhack: ‘‘ Professor Geikie’s Classification of the North Euro- 
pean Glacial Deposits,’ ‘‘ Journal of Geology,’ vol. v, pp. 113-125. 

D. S. Kellogg: ‘‘Glacial Phenomena in Northeastern New York,”’ 
“Science,’”’ June, 17, 1892. 

J. F. Kemp: ‘‘Buried Channels Beneath the Hudson and its Trib- 
utaries,’’ ‘‘American Journal of Science,’’ October, 1908; ‘‘ Geology 
of the Lake Placid Region [New York],”’ ‘‘ Bulletin of the New York 
State Museum,”’ vol. v, pp. 51-67; ‘“‘The Glacial or Post-Glacial 
Diversion of the Bronx River [New York] from its Old Channel,’’ 
“N.Y. Acad. Sci., Trans.,’’ vol. xvi, pp. 18-24; ““An Interesting Dis- 
covery of Human Implements in an Abandoned River Channel in 
Southern Oregon,’’ “‘Science,’’ vol. xxiii, p. 434. 

Percy F. Kendall: ‘‘Glacial Geology of England,” in ‘‘Man and the 
Glacial Period,’”’ pp. 137-181; ‘‘Geological Observations upon some 
Alpine Glaciers,’’ ‘‘ The Glacialists’ Magazine,’’ October, November, 
December, 1894, January and February, 1895. 

C. R. Keyes: “‘Eolian Origin of the Loess,’’ ‘‘ American Journal of 
Science,’’ 1898; ‘Glacial Lakes Hudson-Champlain and St. Law- 
rence,’ ‘‘American Geologist,’’ vol xxxii, pp. 223-229. 

Otto Klotz: ‘‘ Recession of Alaskan Glaciers,’ ‘‘Geographical Jour- 
nal,’’ October, 1907, p. 2. 

F. H. Knowlton: “Notes on the Examination of a Collection of 
Interglacial Wood from Muir Glacier, Alaska,”’ ‘‘ Journal of Geology,”’ 
vol. 111, pp. 527-532. 

H. B. Kiimmel. “Glaciation of Pocono Knob and Mounts Ararat 
and Sugar Loaf, Pennsylvania,’ ‘‘American Journal of Science,” 
February, 1896; and R. D. Salisbury: ‘Lake Passaic: an Extinct 
Glacial Lake,” ‘‘Journal of Geology,” vol. iii, pp. 533-560. 

Joseph Le Conte: ‘Tertiary and Post-Tertiary Changes of the 
Atlantic and Pacific Coast, with a Note on the Mutual Relations of 
Land-elevation and Ice-accumulation during the Quaternary Period,”’ 
“Bulletin of the Geological Society of America,” vol. ii, pp. 323-330; 


724 THE ICE AGE IN NORTH AMERICA. 


‘‘The Origin of Transverse Mountain Valleys and some Glacial 
Phenomena in those of the Sierra Nevada,”’ “‘Cal. University Chron- 
icle,’’ vol. xi, pp. 479-497; ‘The Ozarkian and its Significance in The- 
oretical Geology,’’ ‘“‘Journal of Geology,”’ vol. vii, pp. 525-544. 

J. N. Le Conte: ‘‘Motion of Nisqually Glacier, Mt. Rainier,’’ 
‘Sierra Club Bulletin,’ vol. vi, pp. 108-114. 

W. T. Lee: ‘‘Note on the Glacier of Mount Lyell, California,’’ 
‘‘Journal of Geology,’’ vol. xiii, pp. 358-362; ‘‘The Glacier of Mt. 
Arapahoe, Colorado,” ibid., vol. viii, pp. 647-654. 

E. D. Leffingwell: ‘‘Flaxman Island, A Glacial Remnant,” “‘ Journal 
of Geology,” vol. xvi, pp. 56-63. 

Frank Leverett: ‘‘Pleistocene Fluvial Planes of Western Pennsyl- 
vania,’’ ‘‘American Journal of Science,’’ September, 1891; ‘‘On the 
Correlation of Moraines with Raised Beaches of Lake Erie,” ibid., 
April, 1892; ‘‘Further Study of the Drainage Features of the Upper 
Ohio Basin,’’ ibid., April, 1894; ‘‘On the Correlation of New York 
Moraines with Raised Beaches of Lake Erie,”’ ibid., July, 1895; ‘‘On 
the Significance of the White Clays of the Ohio Region,” ‘‘ American 
Geologist,’ July, 1892; ‘‘Supposed Glacial Manin Southwestern Ohio,” 
and ‘‘ Relation of the Attenuated Drift Border to the Outer Moraine in 
Ohio,’’ ibid., March, 1893; ‘‘Relation of a Loveland, Ohio, I:mple- 
ment-bearing Terrace to the Moraines of the Ice Sheet,”’ ‘‘ Proceedings 
of the A.A.A.S.,”’ vol. xl, 1891; ‘‘The Cincinnati Ice Dam,” ibid.; 
“The Glacial Succession in Ohio,’’ ‘Journal of Geology,” vol. i, pp. 
129-146; ‘“‘Preglacial Valleys of the Mississippi and Tributaries,” 
ibid., vol. 111, pp. 740-763; ‘‘Changes in Drainage in Southern Ohio,” 
‘‘Bulletin of the Scientific Laboratories of Denison Univ.,”’ vol. ix, 
pp. 18-21; ‘‘Correlation of Moraines with Beaches on the Border of 
Lake Erie,’’ ‘‘American Geologist,’’ vol. xxi, pp 195-199; ‘‘ Glacial 
Formations and Drainage Features of the Erie and Ohio Basins,” 
‘Monograph of the United States Geological Survey,”’ xli; ‘Glacial 
Geology of the Grand Rapids Area,’’ ‘‘Michigan Geological Survey,” 
vol. ix, pp. 56-69; ‘‘The Illinois Glacial Lobe,’’ ‘‘Monograph of the 
United States Geological Survey,” xxxviii; ‘‘Lower Rapids of the Mis- 
sissippi River,’ “Journal of Geology,” vol. vii, pp. 1-22; “Old 
Channels of the Mississippi in Southeastern Iowa,’’ ‘‘ Annals of Iowa,”’ 
ser. 3, vol. v, pp. 38-51. ‘‘The Peorian Soil and Weather Zone (Toronto 
Formation?),’’ “Journal of Geology,’ vol. vi, pp. 244-249; “‘ Pleisto- 
cene Features and Deposits of the Chicago Area [Illinois],’’ ‘Bulletin 
of the Chicago Academy of Science,”’ No. ii; ‘‘ Review of the Glacial 
Geology of the Southern Peninsula of Michigan,” ‘‘Michigan Academy 
of Science,” 6th Report, pp. 100-110; ‘‘Report on the Surface Ge- 
ology of Alcona County, Michigan,’’ ‘‘ Annual Report of the Michigan 
Geological Survey,’’ 1901, pp. 35-64; ‘‘Summary of the Literature 
of North American Pleistocene Geology, 1901 and 1902,’’ ‘‘ Journal of 
Geology,’’ vol. xi, pp. 420-428, 498-515, 587-611; ‘‘Water Resources 


BIBLIOGRAPHY. 725 


of Indiana and Ohio,” ‘‘Eighteenth Annual Report of the United 
States Geological Survey,’’ pt. iv, pp. 425-559; ‘‘The Weathered Zone 
(Sangamon) between the Iowan Loess and Illinoian Till Sheet,”’ 
“Journal of Geology,’’ vol. vi, pp. 171-181; ‘‘The Weathered Zone 
(Yarmouth) between the Illinoian and Kansan Till Sheets,’’ ibid., 
vol. vi, p. 238-243; ‘‘Weathering and Erosion as Time Measures,’’ 
‘‘American Journal of Science,’ May, 1909; ‘‘Wells of Northern 
Indiana,” “United States Geological Survey, Water Supply Papers,’’ 
No. xxix. 

J. F. Lewis: ‘‘The Chicago Main Drainage Channel,”’ ‘‘Transac- 
tions of the American Institution of Mining Engineers,’ vol. xxvii, 
pp. 288-332. 

D. F. Lincoln: “Glaciation in the Finger Lake Region of New 
York,’’ ‘‘American Journal of Science,’’ October, 1892; ‘‘Amount of 
Glacial Erosion in the Finger Lake Region of New York,”’ ibid., 
February, 1894. 

A. Lindenkohl: ‘‘Notes on the Submarine Channel of the Hudson 
River, and Other Evidences of Post-Glacial Subsidence of the Middle 
Atlantic Coast Region,’’ ‘‘ American Journal of Science,’ June, 1891. 

A. P. Low: “‘Exploration of the South Shore of Hudson Strait,’’ 
“Canada Geological Survey, An. Report,’ vol. xi, part L, [Glacial, 
pp. 34-47]. 

B.S. Lyman: ‘ Accounting for the Depth of the Wyoming Buried 
Valley (Pennsylvania],’’ -‘“Proceedings of Philadelphia Academy of 
Natural Sciences,”’ vol. liv, pp. 507-509. 

W. A. McBeth: ‘‘The Development of the Wabash Drainage 
System and the Recession of the Ice Sheet in Indiana,’”’ ‘‘ Proceedings 
of the Indiana Academy of Science,”’ for 1900, pp. 184-192; “‘History 
of the Wea Creek in Tippecanoe County,” ibid., for 1901, pp. 244-247 ; 
“An Interesting Bowlder,”’ ibid., for 1899, p. 162; ‘‘The Physical 
Geography of the Region of the Great Bend of the Wabash [Indiana],’’ 
ibid., for 1899, pp. 157-161; ‘‘A Theory to Explain the Western Indiana 
Bowlder Belts,’’ ibid,, for 1900, pp. 192-194; ‘‘Wabash River Terraces 
in Tippecanoe County, Indiana,”’ ibid., for 1901, pp. 237-243. 

T. H. McBride: “‘A Pre-Kansan Peat Bed,” ‘Proceedings of 
the Jowa Academy of Science,”’ vol. iv, pp. 63-66. 

R. G. McConnell: “The Maemillan River, Yukon District,” 
“Canadian Geological Survey,” Summary Report for 1902, pp. 20-36. 

W J McGee: “The Pleistocene History of Northeastern Iowa,’’ 
“Eleventh Annual Report of the United States Geological Survey,”’ 
pp. 199-577. 

P.C. Manning: “Glacial Potholes in Maine,” “‘ Proceedings of the 
Portland Society of Natural History,’’ vol. ii, pp. 185-200. 

V. F. Marsters: ‘‘Topography and Geography of Bean Blossom 
Valley, Monroe County, Indiana,”’ ‘‘ Proceedings of the Indiana Acad- 
emy of Science,’’ 1901, pp. 222-237. 


726 THE ICE AGE IN NORTH AMERICA. 


D. S. Martin: ‘‘Glacial Geology in America,’’ ‘Popular Science 
Monthly,” January, 1899. 

G. C. Matson: “A Contribution to the Study of the Interglacial 
Gorge Problem,”’ ‘‘ Journal of Geology,” vol. xii, pp. 133-151. 

F. E. Matthes: ‘‘The Alps of Montana,” ‘‘ Appalachia,” vol. x, 
pp. 255-276; ‘Glacial Sculpture of Bighorn Mountains, Wyoming,” 
““Twenty-first Annual Report of the United States Geological Survey,”’ 
pt. 11, pp. 167-190; ‘‘The Lewis Range of Northern Montana and its 
Glaciers,’”’ “‘Intern. Geog. Cong. 8th Report,’”’ pp. 478-479. 

G. F. Matthew: ‘ Post-Glacial Faults at St. John, New Brunswick,’’ 
‘‘American Journal of Science,’’ December, 1894. 

C. J. Maury: “An Interglacial Fauna found in Cayuga Valley 
and its Relation to the Pleistocene of Toronto,’’ ‘“‘ Journal of Geology,” 
vol. xvi, pp. 565-567. 

E. T. Mellor: ‘Glacial (Dwyka) Conglomerate of South Africa,’’ 
“American Journal of Science,’’ August, 1905. 

Frederick J. H. Merrill: ‘“Post-Glacial History of the Hudson 
River Valley,’’ ‘‘American Journal of Science,” June, 1891. 

G. P. Merrill: Development of the Glacial Hypothesisin America,” 
‘‘Popular Science Monthly,”’ April, 1906; ‘‘On the Glacial Pothole in, 
the National Museum,” “‘Smithsonian Miscellaneous Collections,” 
vol. xlv. pp. 100-103. 

H. E. Merwin: ‘“‘Some late Wisconsin and Post-Wisconsin Shore- 
lines of North-western Vermont,’ “Report of the Vermont State 
Geologist,’’ 1907-08, pp. 113-137. 

H. R. Mill: ‘‘The Glacial Land-Forms of the Margin of the Alps,’’ 
‘“‘American Journal of Science,’’ February, 1895. 

A. M. Miller: ‘‘High-Level Gravel and Loam Deposits of Ken- 
tucky Rivers,’’ ‘‘American Geologist,’’ November, 1895. 

W. J. Miller: ‘‘Ice Movement and Erosion along the Southwestern 
Adirondacks,’’ ‘‘ American Journal of Science,’’ April, 1909. 

H.T. Montgomery: ‘‘The Glacial Phenomena as Exhibited in North- 
ern Indiana and Southern Michigan and the Resulting Ancient 
Waterways, or the Early History of our Home,” “Publications of 
the Northern Indiana Historical Society,’’ no. 2, 20 pp. 

Joseph Moore: ‘‘ Account of a Morainal Stone Quarry of Upper 
Silurian Limestone near Richmond [Indiana],’’ ‘‘ Proceedings of the 
Indiana Academy of Science,’’ 1896, pp. 75-76. 

F. Morse: ‘‘Recession of the Glaciers of Glacier Bay, Alaska,” 
‘“‘National Geographic Magazine,’”’ January, 1908. 

E. L. Moseley: ‘Submerged Valleysin Sandusky Bay,” ‘‘ National 
Geographic Magazine,” vol. xili, pp. 398-403. 

E. H. Mudge: ‘‘Central Michigan and Post-Glacial Submergence,” 
“American Journal of Science,’’ December, 1895; ‘‘Observations 
along the Valley of Grand River, Michigan,”’ “‘ American Geologist,’ 
November, 1893; ‘‘Mouth of Grand River,” ‘American Jeurnal of 


BIBLIOGRAPHY. 727 


Science,’ July, 1899; ‘“‘Notes on Preglacial Drainage in Michigan,”’ 
ibid., August, 1900; ‘‘Some Features of Pre-Glacial Drainage in 
Michigan,’’ ibid., November, 1897. 

John Muir: ‘‘The Pacific Coast Glaciers,’’ ‘Harriman Alaska Ex- 
pedition,”’ vol. i, pp. 119-135. 

J. N. Nevius: “History of Cayuga Lake Valley [New York],’’ 
“Fifty-first Annual Report New York State Museum,’’ vol. i, pp. 
r131-r153. 

Otto Nordenskjéld: “Tertiary and Quarternary Deposits in the 
Magellan Territories,’’ ‘‘American Geologist,” vol. xxi, pp. 300-309. 

I. H. Ogilvie: ‘‘Effect of Superglacial Débris on the Advance and 
Retreat of Some Canadian Glaciers,’ ‘‘Journal of Geology,’’ vol. 
xii, pp. 722-743; ‘“‘Glacial Phenomena in the Adirondacks and Cham- 
plain Valley,” ibid., vol. x, pp. 379-412. 

H. F. Osborn: “A Glacial Pothole in the Hudson River Shales near 
Catskill, New York,’’ ‘‘ American Naturalist,’”’ vol. xxxiv, pp. 33-36. 

Miss Luella A. Owen: ‘‘The Bluffs of the Missouri River,”’ ‘“‘ Intern. 
Geogr.—_Kongr. Siebenter Verh.,”’ pt. ii, pp. 686-690; ‘‘Evidence on 
the Deposition of Loess,’ ‘‘American Geologist,’’ vol. xxxv, pp. 
291-300; ‘‘The Loess at St. Joesph,” ibid., vol. xxxili, pp. 223-228; 
“More Concerning the Lansing Skeleton,’ “Bibliotheca Sacra,” 
vol. lx, pp. 572-578. 

C. E. Peet: ‘Glacial and Post-Glacial History of the Hudson and 
Champlain Valleys,’ “Journal of Geology,’”’ vol. xii, pp. 415-469, 
617-660. 

Albrecht Penck: ‘“‘Climatic Features of the Pleistocene Ice Age,’’ 
“Geographical Journal,’’ February, 1906; ‘‘Glacial Features in the 
Surface of the Alps,’ ‘‘Journal of Geology,’’ vol. xiii, pp. 1-19. 

G. H. Perkins: ‘“‘Geology of Grand Isle County [Vermont],’’ 
“Vermont Geological Survey, Report of the State Geologist,’ iv, pp. 
103-143. 

S.J. Pierce: ‘‘ Preglacial Cuyahoga Valley,” ‘‘ American Geologist,”’ 
vol. xx, pp. 176-181. 

_ J. W. Powell: “Are there Evidences of Man in the Glacial Grav- 

els?”’ ‘“‘Popular Science Monthly,’’ June, 1893. 

J. A. Price and A. Shoaf: “Spy Run and Poinsett Lake Bottoms,”’ 
“Proceedings of the Indiana Academy of Sciences,”’ 1900, pp. 179-181. 

W. H.C. Pynchon: “Glacial Action in Connecticut,’ ‘Connecticut 
Magazine,” vol. iv, pp. 294-303. 

Charles Rabot: ‘‘Glacial Reservoirs and their Outbursts,’’ ‘“‘Geo- 
graphical Journal,’’ May, 1905. 

T. M. Reade: ‘‘The Glacio-Marine Drift of the Vale of Clwyd,”’ 
“Quarterly Journal of the Geological Society of London,’ vol. 53, 
pp. 341-348. 

H. S. Reed: ‘‘A Meteorological Hypothesis of the Cause of the 
Glacial Epoch,”’ “‘American Geologist,’’. vol. xxv, pp. 109-113. 


728 THE ICE AGH IN NORTH AMERICA. 


Harry F. Reid: ‘The Variations of Glaciers,’’ “Journal of Geol- 
ogy,” vol. ili, pp. 278-288; ‘“‘Studies of Muir Glacier, Alaska,’’ ‘‘Na- - 
tional Geographical Magazine,’”’ vol.iv, pp. 19-84; ‘‘The Flow of Gla- 
ciers and their Stratification,’’? ‘‘Appalachia,’’ vol. xi, pp. 1-6; 
‘“‘Glaciers,’”’ ‘‘Mazama,”’ vol. ii, pp. 119-122; ‘‘Glaciers of Mt. Hood 
and Mount Adams, Ore.,”’ ibid., vol. ii, pp. 195-200; ‘‘The Reservoir 
Lag in Glacial Variations,’’ ‘“‘International Geographical Congress,” 
8th Report, pp. 487-491; ‘Stratification, and Flow of Glaciers,’’ 
‘‘Appalachia,’’ vol, xi, pp. 1-27; ‘‘ Variations of Glaciers’”’ ‘‘ Journal of 
Geology,’ vol. v, pp. 378-383; vol. vi, pp. 473-476; vol. vii, pp. 217- 
225; vol. vill, pp. 154-159; vol. ix, pp. 250-254; vol. x, pp. 313-317, 
vol. xi, pp. 285-288; vol, xii, pp, 252-263; vol. xiii, pp. 313-318; vol. 
xiv, pp. 402-410; vol. xvi, pp. 46-55, 664-668. 

Hans Reusch: ‘‘A note on the Last Stage of the Ice Age in Central 
Scandinavia,” ‘‘ Journal of Geology,” vol. viii, pp. 326-332. 

J.L. Rich: ‘Local Glaciation in the Catskill Mountains,” ‘‘ Journal 
of Geology,”’ vol. xiv, pp. 113-121; ‘‘Marginal Glacial Drainage 
Features in the Finger Lake Region,”’ ibid., vol. xvi, pp. 527-548. 

E. P. Richards: ‘“‘The Gravels and Associated Deposits at New- 
bury,”’ ‘“‘Quarterly Journal of the Geological Society of London,” 
vol. lili, pp. 420-437. . 

I. C. Russell: ‘Are there Glacial Records in the Newark System?”’ 
“American Journal of Science,’’ June, 1891; ‘““Mt. St. Elias and its 
Glaciers,’ ibid.; March, 1892; ‘‘ Origin of the Gravel Deposits beneath 
Muir Glacier, Alaska,’’‘‘ American Geologist,’’ March, 1892; ‘‘ Climatic 
Changes indicated by the Glaciers of North America,” ibid., May, 
1892; ‘‘Notes on the Surface Geology of Alaska,’’ ‘‘Bulletin of the 
Geological Society of America,”’ vol. i, pp. 99-162; ‘‘Second Expedi- 
tion to Mount St. Elias,’’ “Bulletin of the United States Geological 
Survey,”’ 1894; ‘‘Malaspina Glacier,’”’ ‘‘ Journal of Geology,’’ vol. i, 
pp. 219-245; “‘The Influence of Débris on the Flow of Glaciers,”’ ibid., 
vol. iii, pp. 823-832; ‘‘ Alaska: Its Physical Geography,” ‘‘Scottish 
Geographical Magazine,’’ August, 1894; ‘‘Drumlin Areas in Northern 
Michigan,’’ ‘‘American Geologist,’ vol. xxxv, pp. 177-179; ‘‘Geog- 
raphy of the Laurentian Basin,”’ ‘‘Bulletin of the American Geo- 
graphical Society,’ vol. xxx, pp. 226-254; ‘‘A Geological Reconnais- 
sance along the North Shore of Lakes Huron and Michigan,’’ ‘‘Michi- 
gan Geological Survey,’’ Report for 1904, pp. 33-112; ‘‘Glacier 
Cornices,”’ ‘‘ Journal of Geology,’’ vol. xi, pp. 783-785; ‘‘Glaciers of — 
Mount Rainier,’’ ‘“Eighteenth Annual Report of the United States 
Geological Survey,’’ pt. ii, pp. 349-424; ‘Glaciers of North America,”’ 
“‘Geographical Journal,’’ December, 1898; ‘‘Glaciers of North Amer- 
ica; a Reading Lesson for Students of Geography and Geology,” 
(Boston, Ginn & Co., 1897); ‘‘The Great Terrace of the Columbia 
and other Topographic Features in the Neighborhood of Lake Chelan, 
Washington,” ‘‘ American Geolgist,”’ vol. xxii, pp. 362-369; ‘‘ Hanging 


BIBLIOGRAPHY. 729 


» 6c ’ 


Valleys,’’ “Bulletin of the Geological Society of America,’’ vol. xvi, 
pp. 75-90; ‘‘ Plasticity of Glacial Ice,’’‘‘ American Journal of Science,”’ 
April, 1897. 

R. D. Salisbury: “The Drift of the North-German Lowland,”’’ 
*‘American Geologist,’’ May, 1892; “‘Certain Extra-Morainic Drift 
Phenomena of New Jersey,’’ ‘‘ Bulletin of the Geological Society of 
America,” vol. ili, pp. 173-182; “Distinct Glacial Epochs and the 
Criteria for their Recognition,’’ ‘“‘Journal of Geology,’’ vol. i, pp. 
61-84; ‘‘Superglacial Drift,’’ ibid., vol. 11, pp. 613-632; ‘‘The Drift: 
Its Characteristics and Relationships,”’ ibid., vol. 11, pp. 708-724, 837- 
851; ‘‘Agencies which transport Materials on the Earth’s Surface,’’ 
ibid., vol. iii, pp. 70-97; ‘‘ Preglacial Gravels on the Quartzite Range 
near Baraboo, Wisconsin,”’ ibid., vol. iii, pp. 655-667; ‘‘The Green- 
land Expedition of 1895,’’ ibid., vol. iii, pp. 875-902; papers on the 
glacial geology of New Jersey in the State reports for 1891-1894. 

R. D. Salisbury and W. W. Atwood; ‘‘Drift Phenomena in the 
Vicinity of Devils Lake and Baraboo, Wisconsin,”’ “‘ Journal of Geol- 
ogy,’ vol. v, pp. 131-147; ‘“‘The Geography of the Region about 
Devils Lake and the Dalles of the Wisconsin, with Some Notes on 
its Surface Geology,’’ “‘Bulletin of the Wisconsin Geological and 
Natural History Survey,’’ no. v, ed. ser. no. 1, pp. i-x, 1-151; and 
others: ‘‘The Glacial Geology of New Jersey,’’ ‘‘Final Report of 
the New Jersey Geological Survey,’’ vol. v; ‘‘Glacial Work in the 
Western Mountains in 1901,’’ ‘‘Journal of Geology,’’ vol. ix, pp. 
718-731; and E. Blackwelder; ‘‘Glaciation in the Bighorn Mountains,”’ 
“Journal of Geology,’’ vol. xi, pp. 216-223; ‘‘The Local Origin of 
Glacial Drift,’’ ‘“‘Journal of Geology,’’ vol. viii, pp. 426-432; ‘‘New 
York City Folio, Pleistocene Formations,’’ ‘‘Geological Atlas of the 
United States,’’ ‘U.S. Geol. Survey,’’ Folio no. 83, pp. 11-17; ‘‘The 
Surface Formations in Southern New Jersey,’’ ‘‘ Annual Report of 
the New Jersey Geological Survey for 1900,’’ pp. 33-40. 

F.W.Sardeson: ‘Beginning and Recession of St. Anthony Falls,’’ 
“Bulletin of the Geological Society of America,’’ vol. xix, pp. 29-52; 
“The Folding of Subjacent Strata by Glacial Action,’ ‘‘ Journal of 
Geology,’’ vol. xiv, pp 226-232; ‘‘Glacial Deposits in the Driftless 
Area,”’ ‘‘American Geologist,’’ vol. xx, pp. 392-403; ‘‘A Particular 
Case of Glacial Erosion,”’ ‘‘ Journal of Geology,”’ vol. xiii, pp. 351-357; 
‘‘What is the Loess?’’ ‘‘ American Journal of Science,’”’ January, 1899. 

T. E. Savage: ‘‘A Buried Peat Bed in Dodge Township, Union 
County, Iowa,’ ‘‘Proceedings of the Iowa Academy of Science,” 
vol. xi, pp. 103-109; ‘“‘Drift Exposure in Tama County [Iowal],’’ 
ibid., vol. viii, pp. 275-278; ‘‘The Toledo Lobe of Iowan Drift,’’ ibid., 
vol. x, pp. 123-129. 

H.C.Schrader and A. C. Spencer; ‘‘Geologicaland Mineral Resources 
of a Portion of the Copper River District, Alaska,’’ U. 8. 56th Cong., 
2d Sess., House Doc. no. 546 [Glacial, pp. 58-82]. 


730 THE ICE AGE IN NORTH AMERICA. 


E. H. L. Schwarz; “The Three Paleozoic Ages of South Africa,” 
“Journal of Geology,’’ vol. xiv, pp. 683-691. 

A. C. Scott; ‘‘A Brief Summary of Glacier Work,’’ ‘‘ American 
Geologist,’’ vol. xxx, pp. 215-261. 

N.S. Shaler; ‘‘Tertiary and Cretaceous Deposits of Eastern Massa- 
chusetts,’’ ‘‘Bulletin of the Geological Society of America,’’ vol. i, 
pp. 443-452; ‘‘Evidences as to Changes of Sea-Level,’’ ibid., vol. vi, 
pp. 141-166. 

W. H. Sherzer;: ‘‘Glaciers of the Canadian Rockies and Selkirks,”’ 
(Wash. Smithsonian Institution, 1907); ‘‘Ice work in Southeastern 
Michigan,’’ ‘‘Journal of Geology,’ vol. x, pp. 194-216; ‘‘Nature and 
Activity of Canadian Glaciers,’’ ‘‘Canadian Alpine Journal,” vol. 
i. pp. 249-263. 

B. Shimek: “ Additional Observations on the Surface Deposits in 
Iowa,’’ ‘‘Proceedings of the Iowa Academy of Science,”’ vol. iv, pp. 
68-72; ‘‘Is the Loess of Aqueous Origin,’ ibid., vol. v, pp. 32-45; 
‘“The Lansing Deposit not Loess,” ‘‘Bulletin of the Laboratory of 
Natural History of IowaState University,’’ vol. v, pp. 346-352; ‘‘ Loess 
and the Iowan Drift,’’ ibid., vol. v, pp. 352-368; ‘‘The Loess and 
the Lansing Man,’’ ‘‘American Geologist,’’ vol. xxxii, pp. 353-369; 
‘“The Loess of Iowa City and Vicinity,” ibid., vol. xxviii, pp. 344-358; 
“The Loess of Natchez, Mississippi,’”’ ibid., vol. xxx, pp. 279-299; 
“‘Nebraska Loess Man,’’ ‘‘Bulletin of the Geological Society of 
America,’ vol. xix, pp. 243-254. 

C. E. Siebenthal; ‘‘Notes on Glaciation in the Sangre De Cristo 
Range, Colorado,” ‘‘Journal of Geology,”’ vol. xv, pp. 15-22. 

F. W. Simonds; ‘‘Reply to Some Statements in Professor Tarr’s 
‘Lake Cayuga a Rock Basin’,’”’ ‘“‘Ameiican Geologist,’’ July, 1894. 

T.B. Smyth: ‘‘The Buried Moraines of the Shunganunga [Kanas],’’ 
‘Transactions of the Kansas Academy of Science,’’ vol. xv, pp. 
95-104; ‘‘The Closing of Michigan Glacial Lakes,” ibid., vol. xv, pp. 
23-27. 

J. W. Spencer: ‘‘Deformation of the Algonquin Beach and Birth 
of Lake Huron,’’ ‘‘American Journal of Science,’’ January, 1891; 
‘High-Level Shores in the Region of the Great Lakes, and their 
-Deformation,”’ ibid., March, 1891; ‘‘ Deformation of Lundy Beach and 
Birth of Lake Erie,”’ ibid., March, 1894: ‘‘ Duration of Niagara Falls,” 
ibid., December, 1894; ‘‘The Rock Basin of Cayuga Lake, and the 
Age of Niagara Falls,’’ ‘‘American Geolgist,’’ August, 1894; ‘‘ Post- 
Pleistocene Subsidence versus Glacial Dams,”’ ‘‘ Bulletin of the Geo- 
logical Society of America,’’ vol. ii, pp. 465-476; ““A Review of the 
History of the Great Lakes,’’ November, 1894; ‘‘ Origin of the Basins 
of the Great Lakes of America,”’ ‘‘Quarterly Journal of the Geological 
Society,’’ vol. xlvi, pp. 523-533; ‘‘ Niagara as a Timepiece,’’ ‘‘ Popular 
Science Monthly,’’ May, 1896, pp. 1-19; ‘‘An Account of the Re- 
searches Relating to the Great Lakes,’’ ““American Geologist,’’ vol. 


i te 


i 


i a ee eee ee ne ae re 


BIBLIOGRAPHY. 731 


xxi, pp. 110-123; ‘‘ Another Episode in the History of Niagara Falls,”’ 
‘‘ American Journal of Science,’’ December, 1898; ‘‘ Bibliography of 
Submarine Valleys off North America,” ibid., May, 1905; ‘‘On the 
Continental Elevation of the Glacial Epoch,”’ ‘‘ British Association for 
the Advancement of Science,’’ Report, 1897, pp. 661-662; Mr. 
Frank Leverett’s ‘‘Correlation of Moraines with Beaches on the 
Border of Lake Erie,’’ ‘‘ American Geologist,’’ vol. xxi, pp. 393-396; 
“‘Niagara as a Timepiece,”’ ‘‘ Proceedings of the Canadian Institute, 
New Series,’’ vol. i, pp. 101-103; ‘‘Submarine Great Canyon of the 
Hudson River,’’ ‘‘American Journal of Science,’ January, 1905, 
“American Geologist,’? vol. xxxiv, pp. 292-293; “Geographical 
Journal,’’ vol. xxv, pp. 180-190; ‘‘Submarine Valleys off the Amer- 
ican Coast and in the North Atlantic,’’ ‘‘ Bulletin of the Geological 
Society of America,’”’ vol. xiv, pp. 207-226; “‘The Falls of Niagara, 
their Evolution and Varying Relations to the Great Lakes; Char- 
acteristics of the Power and the Effects of its Diversion,’’ ““Canadian 
Geological Survey, Department of Mines,’’ 1907. 

G. H. Squier: ‘“‘Studies in the Driftless Region of Wisconsin,’’ 
“Journal of Geology,’’ vol. v, pp. 825-836; vol. vi, pp. 182-192; vol. vii, 
pp. 79-82. ; 

C. _H. Sternberg: ‘‘Experiences with Early Man in America,’’ 
“Transactions of the Kansas Academy of Science,’’ vol. xviii, pp. 
89-93. 

J. J. Stevenson: ‘‘Some Notes on Southeastern Alaska and its 
People,’ ‘‘Scottish Geographical Magazine,’’ February, 1893; 
“Recent Geology of Spitzbergen,’’ ‘‘Journal of Geology,’’ vol. xiii, 
pp. 611-616. 

G. H. Stone: ‘‘The Osar Gravels on the Coast of Maine,”’ ‘‘ Journal 
of Geology,’’ vol. i, pp. 246-254; ‘‘The Las Animan Glacier,’’ ibid., 
vol. i, pp. 471-474; ‘‘Was Lake Iroquois an Arm of the Sea?’’ 
“Seience,’’ February 20, 1891; ‘‘Glacial Gravels of Maine and their 
Associated Deposits,’ “United States Geological Survey,’’ Mono- 
graph xxxiv; ‘“‘Glaciation of Central Idaho,” ‘‘ American Journal of 
Science,’’ January, 1900; ‘‘Gold Placers in Glaciated Regions,”’’ 
“‘Mines and Minerals,” vol. xx, pp. 492-494. 

Aubrey Strahan: ‘“‘On Glacial Phenomena of Paleozoic Age in the 
Varanger Fiord,’’ “Quarterly Journal of the Geological Society of 
London,” vol. lili, pp. 137-146; ‘‘The Raised Beaches and Glacial 
Deposits of the Varanger Fiord,”’ ibid., vol. liii, pp. 147-156. 

R. S. Tarr: ‘‘The Central Massachusetts Moraine,’’ ‘‘ American 
Journal of Science,”’ February, 1892; ‘‘A Hint with Respect to the 
Origin of Terraces in Giaciated Regions,” ibid., July, 1892; ‘‘The 
Relation of the Secular Decay of Rocks to the Formation of Sedi- 
ments,’ ‘‘American Geologist,’’? July, 1892; ‘Glacial Erosion,’’ 
ibid., September, 1893; ‘‘The Origin of Drumlins,’’ ibid., June, 1894; 
‘Lake Cayuga a Rock Basin,” “ Bulletin of the Geological Society of 


732 THE ICE AGE IN NORTH AMERICA. 


America,’’ vol. v, pp. 339-356; ‘‘Arctic Sea Ice as a Geological 
Agent,’’ ‘‘American Journal of Science,’’ March, 1897; ‘‘ Difference 
in the Climate of the Greenland and American Sides of Davis and 
Baffin’s Bay,’’ ibid., March, 1897; ‘‘ Drainage Features of Central New 
York,” “Bulletin of the Geol. Society of America,” vol. xvi, pp. 229- 
242; ‘Evidence of Glaciation in Labrador and Baffin Land,” ‘‘ Ameri- 
can Geologist,’’ vol. xix, pp. 191-197; ‘‘ Former Extension of Cornell 
Glacier near the Southern End of Melville Bay,’’ ‘‘ Bulletin of the 
Geological Society of America,’’ vol. vili, pp. 251-268; ‘‘Glacial 
Erosion in Alaska,’?’ Popular Science Monthly,’’ February, 1907; 
‘‘Glacial Erosion in the Finger Lake Region of Central New York,” 
“Journal of Geology,’’ vol. xiv, pp. 12-27; ‘‘Glaciation of Mount 
Katadin, Maine,’”’ ‘‘Bulletin of the Geological Society of America,’’ 
vol. xi, pp. 483-448; and L. Martin: ‘‘Glaciers and Glaciation of 
Yakutat Bay, Alaska,’’ ‘Bulletin of the American Geographical 
Society,” vol. xxxviil, pp. 145-167; ‘‘Gorges and Waterfalls of Cen- 
tral New York,” ibid., vol. xxxvii, pp. 193-212; ‘‘ Hanging Valleysin 
the Finger Lake Region of Central New York,’’ ‘‘American Geolo- 
gist,’’? vol. xxxiii, pp. 271-290; ‘‘Margin of the Cornell Glacier,” 
vol. xx, pp. 139-156; ‘‘Moraines of the Seneca and Cayuga Lake Val- — 
leys,’’ ‘‘ Bulletin of the Geological Society of America,’’ vol. xvi, pp. 
215-228; ‘‘ Physical Geography of New York State,” (The Macmillan 
Co., N. Y., 1902); ‘‘Physical Geography of New York State,’’ pt. 8; 
“The Great Lakes and Niagara,”’ ‘‘ Bulletin of the American Geograph- 
ical Society,’’ vol. xxxi, pp. 217-235, 315-348; ‘‘ Position of Hubbard 
Glacier Front in 1792 and 1794,”’ ibid., vol. xxxix, pp. 129-136; ‘‘ Post- 
Glacial and Inter-Glacial (?) Changes of Level at Cape Ann, Massa- 
chusetts,’’ ‘‘ Bulletin of the Harvard College Museum of Comparative 
Zoology,’ vol. 42, pp. 181-191; ‘‘Recent Advance of Glaciers in the 
Yakutat Bay Region,’’ ‘‘ Bulletin of the Geological Society of Amer- 
ica,’’ vol. xviii, pp. 257-286; and L. Martin: ‘‘ Recent Changes of Level 
in Alaska,’ ‘Geographical Journal,’’ July, 1906; ‘‘Some Instances of 
Moderate Glacial Erosion,”’ ‘‘ Journal of Geology,”’ vol. xiii, pp. 160- 
173; ‘‘Valley Glaciers of the Upper Nugsuak Peninsula, Greenland,’’ 
“American Geologist,’’ vol. xix, pp. 262-267; ‘‘Watkins Glen and 
Other Gorges of the Finger Lake Region of Central New York,”’ 
‘Popular Science Monthly,”’ May, 1906; and B. S. Butler: ‘‘Yakutat 
Bay Region, Alaska,’’ ‘‘Professional Paper of the United States 
Geological Survey,’’ 64. 

F. B. Taylor: ‘‘The Highest Old Shore Line on Mackinac Island,’’ 
‘American Journal of Science,’’ March, 1892; ‘‘Changes of Level in 
the Region of the Great Lakes in Recent Geological Time,’’ ibid:, 
January, 1895; ‘‘ Niagara and the Great Lakes,” ibid., April, 1895; “A 
Reconnaissance of the Abandoned Shore Lines of Green Bay,’’ 
“* American Geologist,’’ May, 1894; ‘‘A Reconnaissance of the Aban- 
doned Shore Lines of the South Coast of Lake Superior,”’ ibid., June, 


BIBLIOGRAPHY. 733 


1894; ‘The Limit of Post-Glacial Submergence in the Highlands west 
of Georgian Bay,’’ ibid., November, 1894; ‘‘The Second Lake Algon- 
quin,”’ ibid., February and March, 1895; ‘‘The Nipissing Beach on 
the North Superior Shore,’ ibid., May, 1895; ‘‘ Preliminary Notes on 
Studies of the Great Lakes made in 1895,’’ ibid., April, 1896; ‘‘The 
Ancient Strait at Nipissing,”’ ‘‘ Bulletin of the Geological Society of 
America,”’ vol. v, pp. 620-626; ““The Champlain Submergence and 
Uplift, and their Relation to the Great Lakes and Niagara Falls,” 
“British Association for the Advancement of Science,’’ Report, 1897, 
pp. 652-653, ‘‘Correlation and Reconstruction of Recessional Ice Bor- 
ders in Berkshire County, Massachusetts,’’ ‘Journal of Geology,”’’ 
vol. xi, pp. 323-364; ‘‘Correlation of Erie-Huron Beaches with Outlets 
and Moraines in Southeastern Michigan,’”’ ‘‘Bulletin of the Geo- 
logical Society of America,’’ vol. viii, pp. 31-58; ‘“‘Great Ice Dams 
of Lakes Maumee, Whittlesey and Warren,”’ ‘‘ American Geologist,’’ 
vol. xxiv, pp. 6-38; ‘‘ Lake Adirondack,”’ ibid., vol. xix, pp. 392-396; 
*‘Moraines of Recession and their Significance in Glacial Theory,” 
“Journal of Geology,”’ vol. v, pp. 421-465; ‘‘ Notes on the Abandoned 
Beaches of the North Coast of Lake Superior,’’ ‘‘ American Geologist,” 
vol. xx, pp. 111-128; ‘Origin of the Gorge of the Whirlpool Rapids 
at Niagara,’’ ‘“‘Bulletin of the Geological Society of America,”’ vol. 
ix, pp. 59-84; ‘‘Post-Glacial Changes of Attitude in the Italian and 
Swiss Lakes,’’ ibid., vol. xv, pp. 369-378; ‘‘Scoured Bowlders of the 
Mattawa Valley [Ontario],’’ ‘“American Journal of Science,’’ 1897; 
“Surface Geology of Lapeer County, Michigan; Summary Report of 
Progress,’ ‘“‘Annual Report of the Michigan Geological Survey,”’ 
for 1901, pp. 111-117. 

W. G. Tight: ‘‘Contribution to the Knowledge of the Preglacial 
Drainage of Ohio,’’ ‘‘ Bulletin of the Scientific Laboratories of Deni- 
son University,’ vol. viii, pt. ii, vol. ix, pt.i; ‘‘ Drainage Modifica- 
tions in Southeastern Ohio and Adjacent Parts of West Virginia,” 
“Professional Paper of the United States Geological Survey,’’ No. 
13; ‘‘Drainage Modifications in Washington and Adjacent Coun- 
ties,’ ‘‘Special Papers Ohio State Academy of Science,’’ No. 3, pp. 
11-21; ‘‘Lake Licking—a Contribution to the Buried Drainage of 
Ohio,”’ “‘Second Annual Report of the Ohio State Academy of Science,”’ 
pp. 17-20; ‘‘A Pre-Glacial Valley in Fairfield County [Ohio],’’ ‘‘ Bulle- 
tin of the Scientific Laboratory of Denison University,’’ vol. ix, pt. 
li, pp. 33-37; “‘Some Pre-Glacial Drainage Features in Southern 
Ohio,”’ ibid., vol. ix, pt. ii, pp. 22-32. 

J. L. Tilton: “‘Results of Recent Geological Work in Madison 
County [Iowa],”’ ‘Proceedings of the Iowa Academy of Science,”’ vol. 
iv, pp. 47-54. 

J. E. Todd: ‘‘Striation of Rocks by River Ice,’’ ‘‘ American Geolo- 
gist,’’ June, 1892; ‘‘Pleistocene Problems in Missouri’’ ‘‘ Bulletin of 
the Geological Society of America,’’ vol. v, pp. 531-548; ‘‘ Degreda- 


734 THE ICE AGE IN NORTH AMERICA. 


tion of the Loess,’’ ‘‘ Proceedings of the Iowa Academy of Science,’’ 
vol. v, 46-51; ‘‘The Geology of Beltrami County Minnesota,” “‘ Final 
Report of the Minnesota Geological and Natural History Survey,” 
vol. iv, pp. 131-155; ‘‘The Geology of Hubbard County and North- 
western Portion of Cass County [Minnesota],’”’ ibid., vol. iv, pp. 
82-97; ““The Geology of Marshall, Roseau, and Kittson Counties 
[Minnesota],’’ibid., vol. iv, pp. 117-1380; ‘‘The Geology of Norman 
and Polk Counties [Minnesota],’”’ ibid., vol. iv, pp. 98-116; ‘‘The Mo- 
raines of Southeastern South Dakota and their attendant Deposits,’’ 
‘Bulletin of the United States Geological Survey,’’ No. 158; ‘‘New 
Light on the Drift in South Dakota,’’ ‘‘American Geologist,’ vol. 
xxv, pp. 96-105; ‘‘New Light on the Drift in South Dakota,” ‘‘Pro- 
ceedings of the lowa Academy of Science,”’ vol. vi, pp. 122-130; ‘‘Re- 
vision of the Moraines of Minnesota,”’ ‘‘ American Journal of Science,” 
December, 1898. 

J. H. Todd: ‘‘Some Observations on the Pre-Glacial Drainage of 
Wayne and Adjacent Counties [Ohio],’’ ‘‘Special Papers of the Ohio 
Academy of Science,’’ no. ili, pp. 47-67. ' 

E. N. Transeau: ‘‘On the Geographic Distribution and Ecological 
Relations of the Bog Plant Societies of Northern North America,’’ 
‘Botanical Gazette,’’ vol. xxxvi, pp. 401-420. 

H.L. True: ‘“The Cause of the Glacial Period”’ (Cincinnati, Robert 
Clarke Co., 1902). 

H. W. Turner: “Glacial Potholes in California,’”’ ‘‘ American 
Journal of Science,’’ December, 1892. 

J. B. Tyrrell: ‘Pleistocene of the Winnipeg Basin, ”” <* American 
Geologist,’’ July, 1891; ‘‘ Post-Tertiary Deposits of Manitoba and the 
Adjoining Territories of Northwestern Canada,”’ ‘‘Bulletin of the 
Geological Society of America,’ vol. i, pp. 395-410; ‘‘ Notes on the 
Pleistocene of the Northwest Territories of Canada, Northwest and 
West of Hudson Bay,’’ ‘‘Geological Magazine,’’ September, 1894; 
*‘Genesis of Lake Agassiz,’’ ‘“‘ Journal of Geology,” vol. v, pp, 78-81; 
‘*Glacial Phenomena in the Canadian Yukon District,’ *‘ Bulletin of 
the Geological Society of America,”’ vol. x, pp. 193-198; ‘‘The Glacia- 
tion of North-Central Canada,”’ ‘‘ Report of the British Association for 
the Advancement of Science,’’ 1897, pp. 662-663; ‘‘Glaciation of 
North Central Canada,” ‘‘ Journal of Geology,’’ vol. vi, 147-160; ‘‘Re- 
port on the Doobaunt, Kazan, and Ferguson Rivers and the North- 
west Coast of Hudson Bay, and on Two Overland Routes from Hud- 
son Bay to Lake Winnipweg,”’ ‘‘Canada Geological Survey,’’ n.s. vol. 
ix, Report F. 

J. A. Udden: ‘‘Geology of Louisa County,’’ ‘Iowa Geological 
Survey,’’ vol. xi, pp. 55-126; ‘‘Geology of Pottawatamie County,” 
ibid., vol. xi, pp. 199-277; ‘‘Loess as a Land Deposit,’’ ‘‘ Bulletin 
of the Geological Society of America,’ vol. ix, pp. 6-9; ‘‘ Loess with 
Horizontal Shearing Planes,” ‘‘Journal of Goulony."? vol. x, pp. 


BIBLIOGRAPHY. 735 


245-251; ‘‘Mechanical Composition of Wind Deposits,’’ ‘‘Augus- 
tana Library Publications,’’ no. 1, 69 pp.; ‘‘On the Proboscidean 
Fossils of the Pleistocene Deposits in Illinois and Iowa,’’ ‘‘ Augus- 
tana Library Publications,”’ no. v, pp. 45-57. 

Warren Upham: ‘‘A Review of the Quaternary Era,with Special 
Reference to the Deposits of Flooded Rivers,” ‘‘ American Journal of 
Science,’”’ January, 1891; ‘‘Recent Fossils near Boston,” ibid., March, 
1892; ‘‘Estimates of Geologic Time,” ibid., March, 1893; ‘‘Epeiro- 
genic Movements associated with Glaciation,’’ ibid., August, 1893; 
“Diversity of the Glacial Drift alongits Boundary,’’ ibid., May, 1894; 
“Late Glacial or Champlain Subsidence and Re-elevation of the St. 
Lawrence Basin,”’ ibid., January, 1895; ‘‘Causes and Conditions of 
Glaciation,’’ ‘‘American Geologist,’’ July, 1894; ‘‘The Niagara Gorge 
as a Measure of the Post-Glacial Period,” ibid., July, 1894; ‘“‘ Evidence 
of Superglacial Eskers in Illinois and Northward,’’ ibid., December, 
1894; ‘‘Drumlin Accumulation,” ibid., March, 1895; ‘‘Climatic Con- 
ditions shown by North American Interglacial Deposits,’”’ ibid., 
May, 1895; ‘‘Stages of the Recession of the North American Ice-Sheet 
shown by Glacial Lakes,’’ ibid., June, 1895; ‘‘Correlations of the 
Stages of the Ice Age in North America and Europe,” ibid., August, 
1895; ‘‘Warm Temperate Vegetation near Glaciers,’ ibid., November, 
1895; ‘‘Physical Condition of the Flow of Glaciers,’ ibid., January, 
1896 ;‘‘ The Fiords and Great Lake Basins of North America considered 
as Evidence of Preglacial Continental Elevation and of Depression 
during the Glacial Period,” ‘‘ Bulletin of the Geological Society of 
America,” vol. i, pp. 563-567; ‘‘Glacial Lakes in Canada,”’ ibid., pp. 
243-276; ‘Inequality of Distribution of the Englacial Drift,’ ibid., 
vol. iii, pp. 134-148; ‘‘ Relationship of the Glacial Lakes Warren, Algon- 
quin, Iroquois, and Hudson-Champlain,”’ ibid., pp. 484-487; ‘‘The 
Champlain Submergence,”’ ibid., pp. 508-511; ‘‘Comparison of Pleis- 
tocene and Present Ice-Sheets,’’ ibid., vol. iv, pp. 191-204; ‘‘ Evidences 
of the Derivation of the Kames, Eskers and Moraines of the North 
American Ice-Sheet chiefly from its Englacial Drift,” ibid., vol. v, pp. 
71-86; ‘‘The Succession of Pleistocene Formations in the Mississippi 
and Nelson River Basins,” ibid., pp. 87-100; ‘‘ Discrimination of Gla- 
cial Accumulation and Invasion,”’ ibid., vol. vi, pp. 348-352; ‘‘ Drum- 
lins and Marginal Moraines of Ice-Sheets,’’ ibid., vol. vii, pp. 17-30; 
“Preglacial and Post-Glacial Valleys of the Cuyahoga and Rocky 
Rivers,”’ ibid., pp 327-348; ‘‘ Wave like Progress of an Epeirogenic Up- 
lift,’”’ ‘‘Journal .of Geology,’’ vol. ii, pp. 383-395; ‘‘Walden, Cochitu- 
ate, and Other Lakes inclosed by Modified Drift,’’ ‘“‘ Proceedings of 
- the Boston Society of Natural History,’’ February 18, 1891; ‘‘The Origin 
of Drumlins,’”’ ibid., November 16, 1892; ‘‘The Fishing Banks between 
Cape Cod and Newfoundland,” ibid., March 15, 1893; ‘‘ Deflected 
Glacial Striz in Somerville [Mass.],’’ ibid., March 15, 1893; ‘‘Eskers 
near Rochester, New York,’ “Proceedings of the Rochester Acad- 


736 THE ICE AGE IN NORTH AMERICA. 


emy of Science,” January 9, 1893; ‘‘Greenland Icefields and Life 
in the North Atlantic,” chapters on ‘‘The Plants of Greenland,”’ 
‘“‘The Animals of Greenland,” ‘‘Explorations of the Inland Ice of 
Greenland,”’ ‘‘Comparison of Present and Pleistocene Ice-Sheets,”’’ 
‘* Pleistocene Changes of Level around the Basin of the North Atlan- 
tic,’’ ‘‘The Causes of the Ice Age,’”’ and ‘‘Stages of the Ice Age in 
North America and Europe,’’ ‘‘ Age of the Missouri River,’”’ ‘‘ Ameri- 
can Geologist,’’ vol. xxxiv, pp. 80-87; ‘‘ Age of the St. Croix Dalles,’’ 
ibid., vol. xxxv, pp. 847-355; ‘‘ Antiquity of the Fossil Man of Lansing, 
Kansas,” ibid., vol. xxxii, pp. 185-187; ‘‘ Antiquity of the Races of 
Mankind,”’ ibid., vol. xxxviii, pp. 250-254; ‘‘Ben Nevis, the Last 
Stronghold of the British Ice-Sheet,’’ ibid., vol. xxi, pp. 375-380; 
‘Boulders due to Rock Decay,” ibid., vol. xxxiii, pp. 370-375; 
‘‘Causes of the Ice Age,’’ ‘‘ Journal of Transactions of the Victoria 
Institute,’ vol. xxix; ‘‘Cuyahoga Pre-Glacial Gorge in Cleveland, 
Ohio,’’ ‘‘Bulletin of the Geological Society of America,’ vol. viii, 
pp. 7-13; ‘‘The Divisions of the Ice Age,” ‘‘ Journal of Transactions 
of the Victoria Institute,’”’ vol. xxxiii; ‘‘Drumlins Containing or 
Lying on Modified Drift,’’ ‘‘ American Geologist,’”’ vol. xx, pp. 383- 
387; ‘‘Drumlinsin Glasgow, Scotland,”’ ibid., vol. xxi, pp. 235-243; 
‘‘Englacial Drift in the Mississippi Basin,”’ ibid., vol. xxiii, pp. 369- 
374. ‘‘Evidence of Epeirogenic Movements Causing and Terminat- 
ing the Ice Age,’’ ‘‘ Bulletin of the Geological Society of America,’’ 
vol. x, pp. 5-10; “‘Fiords and Hanging Valleys,’’ ‘‘ American Geolo- 
gist,’’ vol. xxxv, pp. 312-315; ‘‘Fiords and Submerged Valleys of 
Europe,’’ ibid., vol. xxii, pp. 101-108; ‘‘The Fossil Man of Lansing, 
Kansas,’’ ‘‘Records of the Past,’”’ vol. i, pp. 272-275; ‘‘ Geological 
History of the Great Lakes and Niagara Falls,’’ ‘‘ International Quar- 
terly,’’ vol. xi, pp. 248-265; ‘‘The Geology of Aitkin County [Minne- 
sota],’’ Final Report of the Minnesota Geological and Natural History 
Survey, vol. iv, pp. 25-54; ‘‘The Geology of Cass County and of the 
Part of Crow Wing County Northwest of the Mississippi River [Minne- 
sota],’’ ibid., vol. iv, pp. 55-81; “Geology of the Region around Red 
Lake and Soutliward to Whit@Earth [Minnesota],”’ ibid.,.vol. iv, pp. 
155-165; ‘‘Giants’ Kettles Eroded by Moulin Torrents,” ‘‘ Bulletin of 
the Geological Society of America,’ vol. xii, pp. 25-44; ‘Giants’ 
Kettles near Christiania and in Lucerne,’’ ‘‘ American Geologist,’’ 
vol. xxii, pp. 291-299; ‘‘ Glacial and Modified Drift in and near Seattle, 
Tacoma, and Olympia,”’ ibid., vol. xxxiv, pp. 203-214; ‘‘Glacial and 
Modified Drift in Minneapolis, Minnesota,” ib d., vol. xxv, pp. 273- 
299; ‘‘Glacial History of the New England Islands, Cape Cod, and 
Long Island,”’ ibid., vol. xxiv, pp. 79-92; ‘‘Glacial Lake Jean Nico- 
let,’ ibid., vol. xxxii, pp. 330-331; ‘‘Glacial Lake Nicolet and the 
Portage beween the Fox and Wisconsin Rivers,’ ibid., vol. xxxii, 
pp. 105-114; ‘‘Glacial Lakes and Marine Submergence in the Hudson- 
Champlain Valley,’”’ ibid., vol. xxxvi, pp. 285-289; ‘‘Glacial Lakes 


BIBLIOGRAPHY. 737 


Hudson-Champlain and St. Lawrence,” ibid., vol. xxxii, pp. 223-230; 
‘Glacial Rivers and Lakes in Sweden,” ibid., vol. xxi, pp. 230-235; 
‘How long ago was America Peopled?”’ ibid., vol. xxxi, pp. 312-315; 
‘‘Manin the Ice Age at Lansing, Kansas, and Little Falls, Minnesota,’’ 
ibid., vol. xxx, pp. 135-150; ‘‘ The Mecklenburg or Baltic Moraines,”’ 
ibid., vol. xxii, pp. 48-49. ‘‘ Modified Drift in St. Paul, Minnesota,’’ 
“Bulletin of the Geological Society of America,”’ vol. viii, pp. 183-196; 
““Modified Drift and the Champlain Epoch,” ‘‘American Geologist,’’ 
vol. xxiii, pp. 319-324; ‘‘Moraines and Eskers of the Last Glaciation 
in the White Mountains,”’ ibid., vol. xxxili, pp. 7-14; ‘‘ New Evidence 
of Epeirogenic Movements Causing and Ending the Ice Age,”’ ibid., 
vol. xxix, pp. 162-169; ‘‘ Niagara Gorge and St. Davids Channel,’ 
‘‘Bulletin of the Geological Society of America,’’ vol.ix, pp. 101-110; 
“Outer Glacial Drift in the Dakotas, Montana, Idaho and Washing- 
ton,” ‘‘American Geologist,’”’ vol. xxxiv, pp. 151-160; ‘‘The Parallel 
Roads of Glen Roy,” ibid, vol. xxi, pp. 294-300; ‘‘ Past and Future 
of Niagara Falls,’’ “State Reservation at Niagara, Commission,’’ 19th 
An. Rept., pp. 231-254; ‘‘Pleistocene Ice and River Erosion in the 
Saint Croix Valley of Minnesota arid Wisconsin,’’ ‘‘ Bulletin of the 
Geological Society of America,”’ vol. xii, pp. 13-24: “‘ Preglacial Ero- 
sion in the Course of the Niagara Gorge, and its Relaticn to Estimates 
of Postglacial Time,” ‘‘ American Geologist,’’ vol. xxviii, pp. 235-244; 
“Primitive Man and Stone Implementsin the North American Loess,” 
“American Antiquarian,’ vol. xxiv, pp. 413-420; ‘Primitive 
Man in the Ice Age,” ‘‘ Bibliotheca Sacra,” vol. lix, pp. 730-7438; 
“Primitive Man in the Ice Age,” ‘‘Memoirs of Explorations in the 
Basin of the Mississippi,” vol. v, Kakabikansing, pp. 116—-119;‘‘ Primi- 
tive Man in the Somme Valley,” ‘‘ American Geologist,’’ vol. xxii, 
pp. 350-362; ‘‘ Raised Shorelines at Trondhjem [Norway],” ibid., vol. 
xxii, pp. 149-154; “‘Relation of the Lafayette or Ozarkian Uplift of 
North America to Glaciation,” ibid., vol. xix, pp. 339-343; ‘‘Rhyth- 
mic Accumulation of Moraines by Waning Ice Sheets,” ibid., vol. xix, 
pp. 411-417; ‘‘Shell-Bearing Drift of Moel Tryfaen [Wales],” ibid.,vol. 
xxi, pp. 81-86; “Time Divisions of the Ice Age,” “‘ Journal of Transac- 
tions of the Victoria Institute,” vol. xxxiii, pp. 393-410; ‘‘The Toronto 
and Scarboro Drift Series,’’ ‘‘American Geologist,’ vol. xxviii, 
pp. 306-316; ‘‘ Valley Loess and the Fossil Man of Lansing, Kansas,’’ 
ibid., vol. xxxi, p. 25-34; ‘‘ Valley Moraines and Drumlins in the 
English Lake District,’”’ ibid., vol xxi, pp. 165-170. 

F. and W. S. Vauz, Jr.: “‘ Additional Observations on Glaciers in 
British Columbia,”’ ‘‘Proceedings of the Philadelphia Academy of 
Natural Science,’’ 1899, pp. 501-512; ‘‘The Great Glacier of the Ile- 
cillewaet,’’ ‘‘ Appalachia,” vol. ix, pp. 156-165; ‘‘Observations made 
in 1900 on Glaciers in British Columbia,”’ ‘‘ Proceedings of Phila- 
delphia Academy of Natural Science,’’ 1901, pp. 213-215; ‘‘Some Ob- 
servations on the Llecillewaet and Asulkan Glaciers of British Colum- 


738 THE ICE AGE IN NORTH AMERICA. 


bia,”’ ibid., 1899, pp. 121-124; ‘‘Canadian Glaciers in Rockies and 
Selkirks,’’ ‘‘Canadian Alpine Journal,’ vol. i, pp. 138-158. — 

A. C. Veatch: ‘Diversity of the Glacial Period on Long Island,”’ 
‘‘Journal of Geology,’ vol. xi, pp. 762-776. 

Volk, Ernest: “‘The Archeology of the Delaware Valley: 0 Pear. 
body Museum Papers,’’ vol. v. 

A. R. Wallace: ‘‘The Ice Age and its Work,” ‘‘Popular Science 
Monthly,’’ March, April, May, June, 1894. 

T. L. Watson: ‘‘Some Higher Levels in the Post-Glacial Develop- 
ment of the Finger Lakes of New York State,”’ “‘51st. Annual Report, 
New York State Museum,” vol.i, pp. r65-r117; ‘‘Some Notes on the 
Lakes and Valleys of the Upper Nugsuak Peninsula, North Green- 
land,’’ ‘‘Journal of Geology,” vol. vii, pp. 655-666. 

C. L. Webster; ‘‘Preliminary Observations on Some of the Con- 
stituent Elements of the Glacial Drift of Northern Iowa,” “Iowa 
Naturalist,’ vol. i, pp. 82-83. 

L.G. Westgate: ‘‘ Abrasion by Glaciers, Rivers, and Waves,”’ “ Jour- 
nal of Geology,” vol. xv, pp. 113-120; ‘‘The Twin Lakes Glaciated 
Area, Colorado,” ‘‘Journal of Geology,’’ vol. xiii, pp. 285-312. 

A. O. Wheeler: ‘‘Motion of Yoho Glacier,’ ‘‘Canadian Alpine 
Journal,” vol. i, pp. 271-375. 

R. H. Whitbeck: ‘‘The Glacial Period and Modern Geography,”’ 
‘Journal of Geography,’”’ January, 1903; ‘‘The Preglacial Course 
of the Middle Portion of the Genessee River [New York],’’ ‘‘Bulle- 
tin of the American Geographical Society,”’ vol. xxxiv, pp. 32-44. 

O. W. Willcox: ‘‘On Certain Aspects of the Loess of Southwestern 
Iowa,”’ ‘“‘ Journal of Geology,”’ vol. xii, pp. 716-721. . 

E. H. Williams: ‘‘Age of the Extra-Moraine Fringe in Eastern 
Pennsylvania,’ ‘‘American Journal of Science,’’ January, 1894; 
“‘Notes on Southern Ice Limit in Eastern Pennsylvania,”’ ibid., 
March, 1895; ‘‘Extra-Morainic Drift between the Delaware and the 
Schuylkill,”’ ‘‘Bulletin of the Geological Society of America,” vol. 
v, pp. 281-296; ‘‘Kansas Glaciation and its Effects on the River 
System of Northern Pennsylvania,”’ ‘‘Proceedings and Collections 
of the Wyoming [Pa.] Historical and Geological Society,’’ vol. vii, 
pp. 21-28; ‘‘Noteson Kansan Drift in Pennsylvania,” ‘‘ Proceedings 
American Philosophical Society,’’ vol. xxxvii, pp. 84-87. 

Batley Willis: ‘Ames Knob, North Haven, Maine,’ ‘ Bulletin 
of the Geological Society of America,”’ vol. xiv, pp. 201-206; “‘ Drift 
Phenomena of Puget Sound,” ‘‘Bulletin of the Geological Society 
of America,’’ vol. ix, pp. 111-162. . 

S. W. Williston: “‘The Fossil Man of Lansing Kansas,’’ “Popular 
Science Monthly,’’ vol. lxii, pp. 463-473; ‘‘On the Lansing Man,”’ 
“‘American Geologist,’’ vol. xxxv, pp. 342-346; ‘‘The Pleistocene of 
Kansas,’’ “‘Kansas University Geological Survey,”’ vol. ii, pp. 299-308; 
‘Transactions of the Kansas Academy of Science,’’ vol. xv, pp. 90-94. 


BIBLIOGRAPHY. 739 


A. W. G. Wilson: ‘Glaciation of Orford and Sutton Mountains, 
Quebec,’’ ‘‘American Journal of Science,’’ March, 1906; ‘‘ Physical 
Geology of Central Ontario,’’ Can. Inst., Trans., vol. vii, pp. 139-186. 

A. N. Winchell: ‘‘Age of the Great Lakes of North America: A 
Partial Bibliography, with Notes,’ ‘‘American Geologist,’’ vol. 
xix, pp. 336-339. 

N. H. Winchell: ‘‘The Geology of Lake County [Minnesota],’’ 
“Final Report of the Minnesota Geological and Natural History 
Survey,’’ vol. iv, pp. 266-312; ‘‘The Geology of the Northern Portion 
of St. Louis County [Minnesota],”’ ibid., vol. iv, pp. 222-265; ‘‘ Geology 
of the Southern Portion of St. Louis County [Minnesota],’’ ibid., vol. 
iv, pp. 212-221; ‘‘Glacial Lakes of Minnesota,’’ ‘‘ Bulletin of Geolog- 
ical Society of America,’’ vol. xii, pp. 109-128; ‘‘The Lansing [Kan- 
sas] Skeleton,’’ ‘‘ American Geologist,’’ vol. xxx, pp. 189-194; ‘‘The 
Pleistocene Geology of the Concannon Farm, near Lansing, Kansas,”’ 
ibid., vol. xxxi, pp. 263-308; ‘‘Was Man in America in the Glacial 
Period?’’ “Bulletin of the Geological Society of America, vol. xiv, 
pp. 133-152. 

J. B. Woodworth: ‘‘Post-Glacial Eolian Action in Southern New 
England,’’ ‘‘American Journal of Science,’’ January, 1894; ‘‘Some 
Typical Eskers of Southern New England,’’ ‘‘ Proceedings of the Bos- 
ton Society of Natural History,’’ February 7, 1894; ‘“‘ Ancient Water 
Levels of the Champlain and Hudson Valleys,”’ ‘‘ Bulletin of the New 
YorkState Museum,”’ No. 84, pp. 265; ‘‘ Glacial Origin of Older Pleis- 
tocenein Gay Head Clifis, with Note on Fossil Horse of that Sec- 
tion,” “Bulletin of the Geological Society of America,’’ vol. xi, 
pp. 455-460; “‘ Ice-Contact in the Classification of Glacial Deposits,’’ 
“American Geologist,’ vol. xxiii, pp. 80-86; ‘‘ Pleistocene Geology 
of Mooers Quadrangle, being a Portion of Clinton County, includ- 
ing Parts of the Towns of Mooers, Champlain, Altona, Chazy, Dan- 
nemora, and Beekmantown, New York,” “‘Bulletin of the New York 
State Museum,”’ No. 83, pp. 3-60; “‘Pleistocene Geology of Portions 
of Nassau County and Borough of Queens [New York],’’ ibid., 
no. 48, pp. 618-670; ‘Some Glacial Wash-Plains of Southern New 
England,”’ “Bulletin of the Essex Institute,”’ vol. xxix, pp. 71-119. 

Mrs. F. B. Workman: “‘ Ascent of the Great Chogo Loongma Glacier, 
and other Climbs in the Himalayas,” ‘‘ Appalachia,” vol. x, pp. 241- 
255; ‘Further Exploration in the Hunza—Nagar and the Hispar 
Glacier,’ ‘‘Geographical Journal,’’ November, 1908. 

W. H. Workman: ‘Exploration of the Nun Kun Mountain Group 
and its Glaciers,’’ ‘‘Geographical Journal,’’ January, 1908. 

A. A. Wright: ‘Nikitin on Quaternary Deposits of Russia, and 
their Relations to Prehistoric Man,” ‘‘ American Journal of Science,’’ 
June, 1893; ‘‘Extra-Morainic Drift in New Jersey,” ‘‘ American Geol- 
ogist,’’ October, 1892; ‘‘ Limits of the Glaciated Areain New Jersey,’’ 
“Bulletin of the Geological Society of America,’ vol. x, pp. 7-13. 


740 THE ICE AGE IN NORTH AMERICA. 


G. F. Wright: ‘‘Theory of an Interglacial Submergence in Eng- : 


land,’ ‘‘American Journal of Science,’’ January, 1892; ‘‘ Unity of the 
Glacial Epoch,” ibid., November, 1892; ‘‘Continuity of the Glacial 


Period,’”’ ibid., March, 1894; ‘‘Observations on the Glacial Phe- 


nomena of Newfoundland, Labrador, and Southern Greenland,”’ 
ibid., February, 1895; ‘‘Dr. Holst on the Continuity of the Glacial 
Period,’”’ ‘‘American Geologist,’? December, 1895; ‘‘The Supposed. 
Post-Glacial Outlet of the Great Lakes through Lake Nipissing and. 
the Mattawa River,’’ ‘‘ Bulletin of the Geological Society of America,’’ 
vol. iv, pp. 423-427; ‘‘ Age of Second Terrace on the Ohio at Brilliant, 
near Steubenville,”’ ‘‘ Journal of Geology,” vol.iv, pp. 218, 219; ‘‘Man 
and the Glacial Period,’”’ ‘‘Popular Science Monthly,” July, 1891; 
‘Evidences of Glacial Man in Ohio,”’ ibid., May, 1893; ‘‘The Cincin- 
nati Ice Dam,”’ ibid., June, 1894; ‘‘New Evidence of Glacial Man in 
Ohio,’’ ibid., December, 1895; ‘‘ Extra-Morainic Drift in the Susque- 
hanna, Lehigh, and Delaware Valleys,’’ ‘‘Proceedingsof the Phila- 
delphia Academy of Natural Science,’’ December 27, 1892; ‘‘Man and 
the Glacial Period,” ‘‘Science,’’ November 11, 1892; ‘‘Some Detailed 
Evidence of an Ice Age in Eastern America,’’ ibid., February 3, 1893; 
‘‘Mr. Holmes’s Criticism upon the Evidence of Glacial Man,”’ ibid., 
May 19, 1893; ‘‘Glacial Phenomena between Lake Champlain, Lake 
George, and the Hudson River,’ ibid., November 22, 1895; ‘‘ Age of 
the Philadelphia Brick Clay,” ibid., February 14, 1896; ‘‘Man and 
the Glacial Period’’ (‘‘ International Scientific Series,’’ D. Appleton 
& Co., 1892; second edition, 1894); ‘‘Greenland Icefields, and Life 
in the North Atlantic, with a New Discussion of the Causes of the 
Ice Age”’ (D. Appleton & Co., 1896); ‘Age of the Lansing Skeleton,”’ 
‘Records of the Past,’’ vol. ii, pp. 119-124; ‘“‘The Ancient Gorge of 
Hudson River,” ibid., vol. iv, pp. 167-171. ‘‘ Another Glacial Won- 
der,” ‘‘The Nation,” vol. 77, pp. 462-463; ‘‘Chronology of the Glacial 
Epoch in North America,’’? (Abstract) ‘‘Quarterly Journal of the 
Geological Society of London,’’ vol. lxiv, pp. 149-151; ‘‘ Evidence of 
the Agency of Water in the Distribution of Loess in the Missouri 
Valley,”’ ‘‘American Geologist,’ vol. xxxiil, pp. 205-222; ‘‘Glacial 
Man,” ‘‘Records of the Past,’’ vol. ii, pp. 259-271; ‘‘Glacial Move- 
ments in Southern Sweden,’’ ‘‘ American Geologist,’’ vol. xxxvi, pp. 
269-271; ‘‘The Influence of the Glacial Epoch upon the Early His- 
tory of Mankind,” ‘‘Journal of Transactions of the Victoria Insti- 
tute,’’ vol. xl; ‘‘The Lansing Skull and the Early History of Man- 
kind,” ‘‘Bibliotheca Sacra,’”’ vol. 1x, pp. 28-32; ‘‘New Method of 
Estimating the Age of Niagara Falls,’ ‘‘Popular Science Monthly,” 
June, 1899; ‘‘Origin and Distribution of the Loess in Northern China 
and Central Asia,”’ ‘‘ Bulletin of the Geological Society of America,” 
vol. xiii, pp. 127-138; ‘‘The Physical Conditions in North America 
during Man’s Early Occupancy,” ‘‘Records of the Past,’’ vol. iv, 
pp. 15-26; ‘‘ Prof. Shimek’s Criticism of the Aqueous Origin of Loess,”’ 


w se 


BIBLIOGRAPHY. 741 


“American Geologist,’? vol. xxxv, pp. 236-240; “Rate of Lateral 
Erosion at Niagara,’’ ibid, vol. xxix, pp. 140-143; ‘‘Report of the 
Boulder Committee of the Ohio State Academy of Sciences,’’ ‘‘Ohio 
State Academy of Sciences,’ 2d An. Report, pp. 5-10; 3d An. Report, 
pp. 6-7; ‘‘The Revision of Geological Time,’”’ ‘‘ Bibliotheca Sacra,”’ 
vol. lx, pp. 578-582. 


INDEX. 


Aar Glacier, 195, 255, 256. 

Abbeville, France, 623, 624. 

Abbott, Dr. C. C., finds paleolithic imple- 
ments at Trenton, N. J., 541, 619, 621, 
625 et seg., 642, 645,674; on early man in 
Ohio, 641. 

Abbott, Richard, 628. 

Ackley, Pa., 149, 150, 327. 

Adams, Mr. Charles Francis, 701. 

Adams county, Ohio, 170. 

Adams Glacier, 72. 

Adelphi, Ohio, 169, 242. 


Adirondacks, 241, 357, 358, 487; terraces | 


on, 30. 

Africa, glaciation in South, 485. 

Aftonian episode, 224. 

Agassiz, A., on recent elevation of Peru, 
507. 

Agassiz, Louis, discovers glacial motion, 
2; on depth of glaciers, 195; on termi- 
nal moraines in Ammonoosuc Valley, 
N. H., 221; on parallel roads of Glen 
Roy, 364. 

Agassiz Glacier, 30. 

Aire Glacier, 449-451. 

Airy, Sir George B., 498. 

Akron, Ohio, 353. © 

Alaska, islands or, 15, 23, 43, 55, 189; glac- 
iers of, 25 et seg., 40 et seq., 188, 462, 488, 
490; condition of northern, 37; buried 
forests of, 62; rainfall of, 68, 190. 

Alaskan Peninsula, glaciers on, 36. 

Albany, N. Y., 329. 

Aletsch Glacier, 104, 231, 364. 

Alexander Archipelago, 188, 192. 

Alleghany Mountains, 133, 242, 299, 362, 
371, 526. 

Alleghany River, 370,604; valley of erosion, 
228, 300; preglacial drainage of, 307, 308; 
glacial drainage of, 314, 376; terraces on, 
328. 

Alleghany Valley, 161. 


Alpine glaciers, terminal moraines of, 16, 
19; velocity of, 80; size of, 81, 84; depth of, 
104, 195, 201, 448; recession and advance 
of, 105, 496, 600; subglacial streams of, 
254, 255; former extension of, 512. 

Alps, bowlders of, 236, 237, 249;. lakes in, 
364, 365; erosion of, 231, 254, 255, 278; 
plants on, 429, 436; insects of, 438. 

Ameralik Fiord, 99. 

Amherst, Ohio, 124. 

Andes, existing glaciers in, 108; Quater- 
nary uplifts of, 507, 511, 512; ancient 
glaciers in, 512. 

Andover, Mass., kames in, 339; kettle- 
holes in, 572. 

Andover, Me., 349. 

Andrews, Dr. E., on date of glacial period, 
508, 517, 571, 665. 

Androscoggin River, 221, 342, 349. 

Animal remains in glacial deposits, near 
Morgantown, W. Va., 378; in valley of 
the Somme, 624; at Trenton, N.J., 639; 
in California, 690. 

Animals, extinction of, during the Glacial 
period, 436, 706. 

Antarctic Continent, glaciers of, 104, 112; 
icebergs of, 112 et seq.; depth of ice in, 201. 

Antarctic exploration, 120, 121. 

Apennines, 429. 

Appalachian Mountains, 229, 259, 299, 362, 
487; correlated with Carboniferous or 
Permian glaciation, 487, 516. 

Archibald, Pa., 331. 

Arkansas River, 173, 227. 

Armstrong, Dr. A., on transported bowl- 
ders in the Hudson Bay region, 245. 

Aroostook River, 343. 

Asbury, Pa., 148. 

Asia, 490; glaciers of, 104, 107, 108; loess in, 
407 et seq.; existing plants of northeastern, 
422, 426; temperature of northern, 478; 
glaciation of, 484, 485; absence of general 
glaciation in, 513. 


= 


744 


Assiniboin River, 338, 335, 545. 

Atrevida Glacier, 32, 606. 

Attenuated border, 174, 581, 582; chapter 
on, 151-166; in Pennsylvania, 153; age of, 
how determined, 155; formed by glacial 
streams, 156; Chamberlin on, 174. 

Auk Glacier, 27. 

Avalanche Lake, 13. 

Aunt Ann’s Run, Ohio, 600. 

Australia, Carboniferous or Permian glac- 
ial deposits in, 516. 


Babbitt, Miss Franc, paleolithic discover- 
ies of, 619, 621, 654, 655 ez seq. 

Baffin Bay, 92, 527. 

Bainbridge, Ohio, 242, 326, 372, 561. 

‘Bakersfield, Vt., 347. 

Bakewell, Mr., on rate of recession of Ni- 
agara Falls, 539. 

Baldwin, Mr. Prentiss, 40. 

Baltimore and Ohio Railroad cut, 669. 

Bancroft on the antiquity of man, 699. 

Barbour, Mr. E. H., 683, 685. 

Barnstable county, Mass., 137. 

Bassett’s Creek, 5538, 554. 

Bauerman, H., 505. 

Beaches raised, 401, 404, 405, 500, 504, 505, 
655, 664. 

Beach Haven, Pa., 133, 148, 326. 

Beardslee, Commander, 43. 

Beardslee Islands, 43. 

Bears, 436. 

Beaver county, Pa., 242. 

Beaver Creek, 308, 309. 

Becker, G. F., on glaciationand erosion of 
the Sierra, 568, 569; on snow fall in, 570. 

Beech City, Ohio, 326. 

Beech Flats, Ohio, 378, 374, 384. 

Belcher, Sir Edward, visits Kotzebue 
Sound, 37. 

Bell, Dr. R. ., 505, 570; on transported bow!l- 
ders in the Hudson Bay region, 246; on 
Portland promontory, 569. 

Bellevue, Pa., 375, 376, 384. 

Belvidere, N. J., 142, 326, 637. 

Benton, Mr. E. R., on the Richmond train 
of bowlders, 239, 240. 

Benton, Pa., 148. 

Berg Lake, 72. 

Bessels, Dr., on transported bowlders in 
the Hudson Bay region, 245. 

Bethlehem, Pa., 637. 

Big Beaver River, 300, 314, 326-328. 

Bigger township, Ind., 601. 

Big Sandy River, 300, 382, 384. 

Big Stone Lake, 316, 354. 

Birtle, Manitoba, 335. 


INDEX. 


Bismarck, Dakota, 174, 244, 526. 

Biso 1, 37, 486, 675, 690. 

Black River, Ohio, recession of falls of, 560. 

Blake, Mr. William P., on Glaciers of the 
Stickeen River, 25, 27. 

Blandford, W. T., 510. 

Blennerhassett Island, 327. 

Block Island, 187. 

Blue Mountains, N. J., 133, 144. 

Blue Ridge. See Kittatinny Mountain. 

Bolivar, Ohio, 326. 

Bonney, T. G., on cirques, 274. 

Boone county, Ky., terminal moraine in, 
170; bowlders in, 243, 367, 368, 385, 386. 
Borden, Professor, reports vegetal deposits, 

602. 

Boston, Mass., and vicinity, 123, 137, 281 
et seq., 453, 488, 504. 

Bottomley, Mr., experiment by, 5. 

Boussingault, M., experiment by, 4. 

Bowlder-clay. See Till. 

Bowlders, 132, 133; size of, 174, 180, 185, 236 
et seq., 484, 485; elevation of, in ice, 197, 
246 et seq.; transportation, 236 et seq., 238, 
484. : 

Bownocker, Professor, on Kanawha drain- 
age, 309; on Middle Ohio drainage, 309. 

Bradford, Mass., 237. 

Brady Glacier, 74. 

Brainerd, Minn., 660, 661. 

Branner, Professor J. C., on depth of ice 
in Pennsylvania, 197. 

British America, 463; terminal moraine in, 
133; Missouri coteau in, 135, 176, 215 e¢ 
seq., 244; depth of ice in, 199-201; trans- | 
portation of bowlders in, 176, 202, 244 et 
seq.; erosion in, 259; glacial drainage in, 
333 et seq.; preglacial plants of, 425. 

British Columbia, 176, 278; glaciers of, 15, 
139, 179, 191; islands of, 23; rivers of, 25; 
wells in, 185; oscillations of, 505. 

British Isles, maximum post-glacial up- 
lift, 191, 506. 

Brooklyn, N. Y., 140, 360. 

Brown county, Ind., 170, 248, 601. 

Brown county, Ohio, glacial boundary in, 
170, 526; bowlders in, 242. 

Brown, Robert, on Vancouver Island, 185, 
186, 188; on Greenland, 602. 

Brown’s Valley, 316. 

Brunswick, Me., 348. 

Brush Creek, 372 e¢ seq., 384. 

Buffalo, N. Y., 395, 398, 540. 

Burbank, Mr. L. S., on preglacial erosion, 
261. 

Burchill, Mr., reports wood in a well, 
601. 


INDEX. 745 


Buried channels, in trough of the Ohio, 300, 
- 301, 309, 644; in Knox county, Ohio, 301; 
connecting Beaver Creek with Grand 
River, 302; in Clark county, Ohio, 302; 


connecting Laké Ontario with the Hud- | 
son, 303; in Cuyahoga county, Ohio, 304; 

between Lakes Huron and Ontario, 305; | 
in Michigan and Illinois, 306; in Penu- | 
sylvania, 307, 311, 332; in New York, 305, | 


808; in Canada, 312; relation of, to min- 

ing interests, 332; from Whirlpool to St. 

Davids, 537; in Minnesota, 553 et seq. 
Buried forests at Muir Glacier, 62 et seq., 


233, 234, 592; theory of, 576, 579; in Ohio, | 


592, 593; in Alaska, 606. 
Bute Inlet, 186. 
Butler county, Ohio, strize in, 591; organic 


remains in glacial deposits in, 592, 598 et 


seq., 601, 603. 


Butterflies, Alpine species of, upon the 


White Mountains, 438. 


Cairo, Ill., 228. 
Calaveras skull, 693 et seg., 697 et seq., 700. 
California, 409; existing glaciers in, 13 et seq.; 


ancient glaciers in, 176, 177, 179, 180; ter- | 
minal moraines in, 222; prehistoric man 
in, 417, 688; flora of, 426; river beds of, / 


688 et seq. 
Camel, 436, 690. 
Campbell county, Ky., 170, 367. 
Canada, 241, 313, 325; depth of ice in, 201; 
of till in, 258; buried channels in, 304, 312; 
lake ridges of, 398; salt deposits of, 464. 
Canadian Pacific Railway, 13, 25. 
Canadian Rockies, glaciers in, 13. 
Canton, Ohio, 168, 326. 
Cape Agassiz, 97. 


Cape Breton Island, absence of Quaternary 


marine beds on, 504. 
Cape Cod, 137, 139, 140, 207, 237, 238, 348. 
Cape Dudley Digges, glacier near, 86. 
Cape Forbes, 97. 
Cape St. Roque, 472. 


Carboniferous glacial epochs, 487, 509, 515, 


518. 
Caribou, 675. 


Cari, Mr., on preglacial drainage, 302, 307, 


308. 
Carmichaels, Pa., 603. 
Carr, Mr. Lucien, finds palzoliths, 627. 
Carroll county, N. H., 351. 
Carroll Glacier, 73. 
Carrollton, N. Y., 308. 
Carver visits Falls of St. Anthony, 557. 


Cascade range, 15, 19, 23, 135, 177, 178, 191, | 


193, 417. 


Cat, 436. 

Catskill Mountains, 147, 195, 198. 

Cattaraugus county, N. Y., 149, 308, 398. 

Caucasus Mountains, 107, 429. 

Cause of the Glacial period, chapter on, 
461-531; not strictly a geological question, 
461, 529; cold not a sufficient, 461; theo- 
ries of the, enumerated, 463; not a shifting 
of the poles, 463; not solely excessive 
moisture, 464; not the depletion of car- 
bon dioxide in the atmosphere, 464, 465; 
changes in the distribution of land and 
water, a possible, 495 et seg.; continental 
elevations a probable, 496 e¢ seq.; varia- 
tions in the temperature of space,andthe 
heat of the sun, a possible, 465; Croll’s 
theory of, 466 et seg., 529; precession of 
the equinoxes, a, 466 et seq.; changes in 
eccentricity of the earth’s orbit, a, 468; 
changes in the Gulf Stream, 469 ef seq.; 
relation of trade-winds to, 470; of Cape 
St. Roque to, 472 et seq,; relative coolness 
of the southern hemisphere, a, 474, 475; 
Woeikoff’s explanation, 475, 476; ignor- 
ance of the laws governing the distribu- 
tion of the heat upon the earth, 477, 530; 
inequality of this distribution, 478, 529; 
diathermaney of the atmosphere, 479, 
530; defective evidence of former glacial 
periods, 481 et seq., 530; local centers of 
dispersion, 525 et seg., 531; indirect influ- 
ence of Greenland ice, 527; present ignor- 
ance of, 528, 531. 

Cedar wood in glacial deposits, 592,598-600, 
603. 

Centers of radiation, 179, 207 et seq.; 527. 

Central Pacific Railroad, 608. 

Chaleurs, Bay of, marine beds overlying 
glacial drift in, 504. 

Chalmers, Robert, 504. 

Chamberlin, Pres. T.C., 391, 500, 562, 563; 
on the Greenland glaciers, 102; on the 
position of bowlders in clay, 130; on rock- 
scoring, 133; discovers terminal moraine, 
134; on loess, 172,412, 413; attenuated bor- 
der, 174; on glacial boundary in Dakota, 
175; west of Dakota, 176; on moraine of 
central New York, 206; on moraine west 
of the Alleghanies, 207; on tne Kettle 
Range, 211, 212, 221, 528; on depth of till, 
258; on drumlins, 286, 292; on Croll’s 
theory of successive glacial epochs, 489, 
575; on post-glacial denudation in Wis- 
consin, 568; on two glacial epochs, 575, 
578. 

Champaign county, Ohio, 257, 258, 302. 

Chaney Glacier, 13. 


746 


Chappaquiddick Island, 137. 

Charpentier Glacier, 74. 

Charleston, W. Va., 379, 604. 

Chatham Strait, 42, 59. 

Chazy, N. Y., 320, 347. 

Cherryfield, Me., 348. 

Cherry Valley, Pa., 195 et seq., 247. 

Chesapeake and Ohio Railroad cut, 379. 

Chewtown, Pa., 326. 

Cheyenne River, 174, 175, 244, 336, 545. 

Chicago, IIl., 547. 

Chili, glaciersin, 104, 108, 109. 

Chilkat, Alaska, 27, 29. 

Chillicothe, Ohio, 242, 326, 561, 602. 

China, loess in, 407 ef seq.; flora of, 426, 
427. 

Chippewa Creek, 542. 

Christianshaab Glacier, 99. 

Chugatch Alps, Alaska, glaciers ou, 36. 

Ciucinnati, Ohio, 170, 301, 302, 327, 367, 592, 
643, 644; glacial dam at, 366 et seg., 394, 
603. 

Cirques, description of, 272; formation of, 
274 et seq., 355; prevalence of, 277. 

Clark county, Ohio, 302. 

Clarksburg, W. Va., 378. 

Claymont, Del., palzolithic implement 
discovered at, 669 et seq. 

Claypole, Professor E. W., 498; on depthof 
drift, 257; on Cinciunatiice-dam 385-387 
et seq.; on the Deluge, 438. 

Cleavering, explorations by, 98. 

Clermont county, Ohio, glacial boundary 
in, 170; bowlders in, 242; vegetable de- 
posits in, 602. 

Cleveland, Ohio, 304, 367. 

Climate, preglacial about the north pole, 
424, 480, 437. 

Close, Mr. M. H., on drumlins, 290, 291. 

Coast Range, 15, 23, 186, 193, 429. 

Colchagua, 109. 

Cole’s Spring, N. Y., 308. 

Coleman, Professor A. P., 584, 585, 587. 

Collett, Professor, reports vegetable depos- 
its in Indiana, 603. 

Collomb, M. E., on subglacial streams in 
the Alps, 255. 

Colorado, 222, 274, 441; former glaciers in, 
176, 177. 

Colorado River, 228. 

Cols, 156, 158, 159, 160, 163, 164, 309, 310, 317, 
319, 336, 393, 394, 542, 563, 587. 

Columbia deposits, 633 et seq., 671. 

Columbia River, 228. 

Columbiana county, Ohio, eee in, 167; 
terminal moraine in, 168; bowlders in, 
242, 326. 


INDEX. 


Columbus, Mount Vernon, and Akron 
Railroad cut, 169. 

Concord, N. H., 330. 

Conewango Creek, 149-150, 162, 207,308, 326. 

Connecticut, depth of ice in, 195, 199; 
transported bowlders in, 238; depth of 
till in, uncertain, 259; drumlins in, 285. 

Connecticut River, 283, 342, 343, 345 et seq., 
660; glacial drainage of, 330, 331, 486, 635. 

Connell, Mr. J. M., reports wood in a well, 
602. 

Contocook River, 330. 

Contractions of the earth, probably causing 
glaciation, 497, 499, 509, 514. 

Cook, Captain, 35; on icebergs of the South- 
ern Ocean, 115, 116. 

Cook, F. A., 99, 100. 

Cook, Professor George H., 639, 675; dis- 
covers terminal moraine, 134, 221; mo- 
raines of retrocession, 207; on trans- 
ported bowlders, 241. 

Coralislands indicating subsidence, 508. 

Cornish, N. H., 351. 

Coteau des Prairies, 212, 214, 362, 415, 662. 

Coulée, 219, 334. 

Cowlitz River, 21. 

Crenate character of the glacial margin, 
132, 138, 442 et seq. 

Cresson, Mr. H. T., paleolithic discover- 
ies of, 619, 622; at Medora, Ind., 649-653; 
at Claymont, Del., 669, 671 et seq., 675. 

Crevasses. See Fissures. 

Croll, Mr. J., 497, 509, 512, 516-518; theory 
of glacial motion, 6; on icebergs in South- 
ern Ocean, 117 et seg.; on depth of ice in 
the Antarctic Continent, 201; theory of 
the Cause of the Glacial period, 466 e¢ 
seq., 532, 534, 562; on date of Glacial 
period, 574, 604; on post-glacial erosion 
in Scotland, 568; onsuccession of glacial 
periods, 481 et seq., 575; on rate of denu- 
dation, 614. 

Crosby, Professor W. O., 238, 507, 509. 

Cross Sound, 29, 42, 48, 59-61, 189. 

Crust, relation of the earth’s, and interior, 
498, 502, 594. 

Cuba, post-glacial elevation of, 507. 

Cumming, Mr. G. M., 702. 

Cuyahoga River, 303. 

Cypress Hills, 199, 200. 


Dakota, glacial boundary in, 133, 172 e 
seqg., 441, 442; marginal drainage in, 174, 
175, 332; fringe in, 174; Coteau des Prairies 
in, 212, 214, 362, 415; Missouri coteau in, 
215, 217, 332; bowlders in, 243, 244; lakes 
in, 362; loess in, 2438, 416. 


INDEX. 


Dall, W. H., explorations of, in Alaska, 29; | 
in Kotzebue Sound, 37; in northern 
Alaska, 38. | 

Dana, Professor J. D., 327, 497, 498, 509, 
514, 519, 528; on depth of ice, 199, 201; on 
kames in the Connecticut Valley, 346; 
on the floods of the Connecticut Valley, 
346, 635. 

Danville, Ohio, 169. 

Darrtown, Ohio, 598. 

Darwin, Charles, 514, 706; on glaciers o 
South America, 109 eé seg.; on dust- 
storms, 409; on earthworms, 418. 

Darwin, Professor G. H., 497. 

Date of the Glacial period, 376, 641, 665, 
508, 517; chapter on, 532-615; astronomi- 
cal evidence insufficient, 532; calcula- 
tious of affected by uniformitarianism, 


533; tendency to make more recent, 533; 


question of, geological, not astronomical, 
534; calculated from the erosion below 


Niagara Falls, 536 et seg.; below the | 
Falls of St. Anthony, 552 et seq.; from | 


falls in northern Ohio, 560; from Paint 
Creek cut-off, 561; from erosion of Rac- 
coon Creek, 564; of Plum Creek, 565- 
567; from the shores of Lake Michigan, 
571; from deposition in kettle-hole, 
Andover, Mass., 572; bearing of theory 
of successive Glacial periods upon the 
subject of, 575; freshness of vegetable 
deposits indicates a recent, 592 et seq.; 
buried peat-beds no bar to theory of 
a recent, 594 et seq.; evidence from Lakes 
Lahontan and Bonneville concerning, 
607 et seg.; Prestwich on, 613. 

Davidson Glacier, 27. 

Davis, Professor William M., on drumlins,- 
284, 285 et seq., 290 et seq.; on glacial lakes, 
364, 365. 

Davis Strait, 85, 449. 

- Dawkins, Professor Boyd, on the origin 
of bowlder-clays of Britain, 448, 449; 
visits Trenton,N. J., 619, 628, 629. 

Dawson, G. M., 179, 505, 506; discovers 
terminal moraine, 134; on Missouri co- 
teau, 176, 217 et seqg.; on glacial phenom- 
ena of Bute Inlet, 186 et seq,; expedition 
to the Yukon, 190; on depth of ice, 199; 
on transportation of bowlders, 199, 202, 
244, 245; on the glacial theory, 200; on | 
junction of two ice-streams of the North- | 
west, 213; on cirques, 278; on glacial 
drainage, 333. 

Dawson, Sir William, 501, 504; on prehis- 
toric man in California, 698. 


747 


Dead Sea, Palestine, gravel deposits about 
the, records of the Glacial period, 612. 

Deblois, Me., 348. 

Delaware, palzolithic discoveries in, 669 
et seq. 

Delaware River, 133, 136, 141, 144, 145, 228, 
325, 326, 358, 534, 633, 684, 635, 636, 639, 
640, 669, 671, 675. 

Delaware Water-Gap, 146, 196, 197, 228, 247 
et seq., 260, 352, 633, 637. 

Delta terraces, 326 e¢ seq.; in New Hamp- 
shire, 330; in Minnesota, 334; in Maine, 
348, 349; on Cape Cod and Long Island, 
349; in Wisconsin, 350. 

Deluge, the, perhaps connected with the 
Glacial period, 438. 

Depth of ice during the Glacial period, 413, 
503, 504, 519; in Yellowstone Park, 177; 
in California, 180; in Maine, 194, 195; in 
New Hampshire, 194; in Vermont, 194; 
in Massachusetts, 195; in Connecticut, 
195, 199; in New York, 195, 261; in Penn- 
sylvania, 195, 197, 198; in New Jersey, 
198, 634; in British America, 199, 200; 
over the region of the Great Lakes, 200, 
201; in Greenland, 201, 202; in the Alps, 
201,448; inthe Antarctic Continent, 201; 
in Labrador, 202; in Norway, 447; on the 
Harz Mountains, 447; in Scotland, 448; 
in England, 450; effect on snow-fall, 528. 

Desor, on depth of glaciers, 195; on erosion 
in the Alps, 255; on rate of recession of 
Niagara Falls, 539. 

Devil’s Lake, 211. 

Diamond Peak, 19. 

Diller, Mr., on glaciers of the Cascade 
Range, 19. 

Dirt Glacier, 72. 

Disco Bay, 75. 

Disenchantment Bay, 31, 32. 

District of Columbia, 671. 

Dixon’s Entrance, 30. 

Dog, 436. 

Dolager’s nunataks, 81. 

Dolfus, on erosion in the Alps, 254. 

Dolphins, 436. 

Don River, Can., 584, 585. 

Driftless area of Wisconsin, 134, 413, 528. 

Drumlins, chapter on, 281-297; locality of, 
281, 284 et seq.; description of, 22, 282 et 
seq.; Upham on, 282, 289, 292; direction 
of the axes of, 283, 284, 287, 289, 292; Davis 
on, 284 et seq., 290 e¢ seq.; in northeastern 
Massachusetts, 284; Percival on, 285; 
Johnson on, 286, 291; Chamberlin on, 
286, 292; theory of, 287 et seq.; absence of 
kettle-holes in, 288; earlier than kames, 


748 


288; Shaler on, 288; King on, 288; Hitch- 
cock on, 290, 292; Close on, 290; Geikie 
on, 291. 

D’Urville, Explorations of, in the Antare- 
tic Continent, 114. 

Dust-fogs, 409, 410. 

Dutton, Captain C. E., 498. 

Dying Glacier, 73. 


Eagle, Wis., 211, 350. 

Earthworms and loess, 418. 

Easton, Pa., 142, 634. 

Eccentricity of the earth’s orbit, varia- 
tions of, 468, 518; not coincident with the 
latest epoch of glaciation, 509, 517; prob- 
ably not influential in causing glaci- 
ation, 518. 

Klephauts, 436, 437, 624. 

Elevation of bowlders in ice, in Pennsyl- 
vania,197, 241, 247 etseq.; inBritish Amer- 
ica, 200, 244; in Massachusetts, 237, 239, 
240; in New Hampshire, 246, 247; in Ver- 
mont, 247; in Maine, 247; explanation of, 
250 et seq. 

Elevation probably causing glaciation, 
497, 508 et seq.; due to removal of the ice- 
sheet, 499, 500, 506. 

Elizabeth Islands, 137, 140, 203, 360. 

Elliott, H. W., on Alaskan glaciers, 30. 

Ells, Mr. R. W., on buried channels in 
Canada, 312. 

Ellsmere Land, glaciers in, 102. 

Elyria, Ohio, 560. 

Emerson, Professor, on marginal lakes of 
the Connecticut Valley, 347. 

Emmons, Mr. S. F., ascent of Mount Ta- 
coma by, 22. 

England, 229, 534; glaciers in, 446, 448 e¢ 
seq.; changes of level in, 453; paleeoliths 
in, 616, 624; preglacial man in, 534, 676. 

Equador, 108. 

Erichsen, M., 9%. 

Erosion by water, 226 et seq., 279, 298 et 
seq., 372, 488, 536 et seq.; compared with 
that of ice, 227, 355; chemical, 229, 568; 
glacial, 230 et seg.; preglacial, 226 et seq.; 
261,298 et seq.; post-glacial ,298, 536et seq. 

Eschscholtz Bay, 36, 37. 

Eskers.. See Kames. 

Eskimos, 245, 440, 623, 641; lineal descend- 
ants of preglacial man, 438, 706, 707. 

Essex County, Mass., 285, 289. 

Hurope, existing glaciers of, 104 et seq., 110, 
glacial erosion in, 231, 232, 254, 255, 260, 
278, 294 et seq.; transported bowlders in, 
236, 237; drumlins in, 290, 291; kames in, 
339, 340; glacial lakes in, 364, 365; loess in, 


INDEX. 


410; preglacial plants of, 428; et seq.; dur- 
ing the Glacial period, chapter on, 445- 
459; successive Glacial periods in, 483- 
486; interglacial man in, 623-625; Qua- 
ternary oscillations in, 506. 

Evans, Mr., 624. . 

Ewing, Professor A. L., on chemical eros- 
ion in the Nittany Valley, 229, 230. 


Fairfield county, Ohio, glacial boundary 
in, 169; bowlders in, 242. 

Falconer, Dr., 624. 

Falis of Minnehaha, post-glacial, 303. 

Falls of Niagara, 575; post-glacial, 303; 
formation of, 536; rate of recession of, 
536 et seq., 665, 706. 

Falls of St. Anthony, 311, 575, 655; post- 
glacial, 303, 552 et seq.; rate of recession 
of, 557 et seq.; 665. 

Falmouth, Mass., 204 et seq. 

Fargo, Minn., 334. 

Farée Islands, 506. 

Favorite Glacier, 74. 

Finger Lakes, New York, 206, 352, 353, 
358, 363. 

Fiords, 501, 502, 506. 

Fisher, Rev. O., 498.. 

Fisher’s Island, 140. 

Fishing Creek, 148. 

Fissures in glacial ice, 8, 19, 50, 93, 95, 96. 

Flathead River, 13. 

Floods at the close of the Glacial period, 
314 e¢ seq., 346 et seq., 387 et seg., 558, 634- 
638. 

Floras of Farée Islands and Iceland, 506. 

Florence, Ky., 367. 

Fondalen Glacier, 106, 233. 

Foote, Professor H. C., onsediment of sub- 
glacial streams, 68. 

Forbes, Professor J. D., discovers glacial 
motion, 2, 88, 94; on transported bowl- 
ders in the Alps, 237. 

Forel, M., on recession and advance of 
Alpine glaciers, 105. 

Fort Snelling, 315, 665; coutrast between 
bluffs above and those below, 553, 554. 

Fort Wrangel, 27, 39, 136, 188. 

Foshay, Mr. P. Max, on buried channels, 
302. 

Fossiliferous marine beds overlying glacial 
drift, 504, 505. 

Fossils at Glens Ferry, 704 et seq. 

Fosters Flats, 550. 

Four-mile Creek, Ohio, 598, 600. 

France, 487; dust-shower in, 410; palzo- 
liths in, 616, 623, 624; interglacial man in, 
676. 


INDEX. 


Frankfort, Ohio, 602. 

Franklin, Pa., 326, 328. 

Franz-Joseph Land, 107. 

Fraser River, 25, 228. 

Frederickshaab Glacier, 
slope of, 201. 

Freehold, Pa., 598. 

French Creek, Pa., 308, 326, 328. 

Frere, Mr. John, 624. 

Fringe, the, of the glaciated area, 167, 174, 
234,244. 


100, 101, 366; 


Gabb, Mr. William M., 507. 

Gastaldi, B., on cirques, 274; on glacial 
deposits in Italy, 486. 

Geikie, Professor A ., 498, 510, 512; on the 
extent of glaciation in Europe, 447, 448; 
in Scotland, 483. 

Geikie, Professor James, 497, 506, 509, 512, 
517; on drumlins, 291; on glacial erosion, 
294 et seq.; on composition of kames, 
339, 340; on Glacial period in Great 
Britain, 445, 449; theory of cause of Gla- 
cial period, 466 eé seq.; on glaciation in 
‘Scotland, 484. 

Geikie Glacier, 74. 

Genesee River, 303. 

Germantown, Ohio, 592, 593, 597, 598, 600. 

Gibraltar Island, Ohio, 266. 

Gibraltar, Strait of, migratious across, 507. 

Gietroz Glacier, 365. 

Gilbert, Mr. G. K., 498, 508, 517, 542, 612; 
on the moraine of Maumee Valley, 207 
et seq., 266; onlake ridges, 395; on Croll’s 
theory of successive glacial epochs, 489, 
575; on recession of Niagara Falls, 540; 
on Lake Bonneville, 611; on date of Gla- 
cial period, 665. 

Gilder, Mr. Robert F., 683. 

Girdled Glacier, 72. 

Glacial boundary in North America, ser- 
rate character of, 132; crenate character 
of, 132, 133; chapters on, 134-167; dis- 
coverers of, 134; not always a terminal 
moraine, 135; south of New England, 
137 et seq.; across New Jersey, 140, 141; 
across Pennsylvania, 145 e¢ seq.; limits 
of error respecting, 148 et seq.; in New 
York, 149 e¢ seq.; in Ohio, 167 et seq.; in 
Kentucky, 170; in Indiana, 170; in Illi- 
nois, 170, 315; beyond the Mississsippi, 
172; beyond the Missouri, 174; in British 
America, 176; beyond the Rocky Moun- 
tains, 176 et seq.; in California, 179; in 
Washington State, 182; in British Co- 
lumbia,183; in Alaska, 189; cause of ir- 
regularity, 441; notes, 604. 


749 


Glacial dams, 355, 535, 665; in the Cone- 
wango, 150; at the mouth of the Lehigh, 
153; across Kansas and Platte Rivers, 
172, 414; in headwaters of Arkansas and 
Platte Rivers, 177; in Leevining River, 
222; in New Hampshire, 363; in New 
York, 363; in New Jersey, 363; in the 
Alps,364; in Scotland, 364; in Greenland, 
366; in the Ohio at Cincinnati, 366 ed seq., 
603; in England, 451. 

Glacial deposits contrasted with aqueous, 
129 et seq.; factors determining extent of, 
135, 203; cause of stratification in, 142. 

Glacial drainage, terraces produced by, 
150, 319, 323 ef seq.; chapter on, 313-336; 
floods of, 313 et seq.; from the Red River 
basin, 313, 315, 316; in the valleys of the 
Mohawk and Hudson, 329; from the Con- 
tocook Valley, N. H., 330; in Grafton 
county, N. H., 331; in eastern Penn- 
sylvania, 332; in Dakota, 175, 332, 336; 
from the valley of the Saskatchewan, 
333; in southwestern Manitoba, 334; in 
southern Minnesota, 336; marked by 
kames, 341, 348; in the walley of the Con- 
necticut, 346 et seq., 6385; in the Little 
Miami, 644. 

Glacial erosion, in the State of Washing- 
ton, 22; manner of, 230 et seq.; variation 
of, 232; small near the margin, 233 et seq.; 
in Greenland, 253, 256; in the Alps, 254, 
278;in British America, 257, 278;in Penn- 
sylvania, 196, 260; in Scandinavia, 260; 
asefiected by secular disintegration, 261 
et seqg.; at the west end of Lake Erie, 262 
et seq.; of rock basins in the high Sierra, 
267; in the Yosemite Valley, 270, 271; of 
cirques, 271 et seq.; Russell on, 272; Lo- 
range on, 276; of fiords, 278; of lake- 
basins in Europe, 278; summary con- 
cerning, 279 et seq.; J. Geikie on inequal- 
ities of, 294 et seq. 

Glacial lakes, 356.e¢ seq., 415, 416, 665; on 
Pocono Mountain, 148; in Kansas and 
Platte Rivers, 172, 414; in the Platte and 
Arkansas, 177; in Leevining River, 222; 
in the Sierra, 269; in Contocook Valley, 
N. H., 330; kinds of, 359; occupying ket- 
tle-holes, 359 et seg.; caused by dams of 
glacial débris, 362 et seg.; Lake Winne- 
-pesaukee, 363; in New York and New 
Jersey, 363; caused by dams of ice, 364 
et seq.; in the Alps, 364; in Scotland, 364; 
in Greenland, 366; in the Ohio, 370, 386; 
in England, 451. 

Glacial periods, supposed succession of, 
468, 481 et seq., 488, 532; lack of evidence 


750 INDEX. 


concerning, explained, 481; in Great | 
_ Britain, 483, 484; in South Africa and 
. India, 484, 485; in Switzerland and Italy, 
486; in North America, 486 et seq. 

Glacial striae. See Rock Scoring. 

Glacial theory, confirmations of, 130, 132, 
133, 143, 183, 240, 323, 326 et seq., objec- 
tions to, by Canadian geologists, 200. 

Glaciation, probable causes, 497-519. 

Glaciation, signs of former, chapter on, 

_108-133; seratches on the rocks, 123 et 
seq.; unstratified deposits, 129 et seq.; 
distribution of bowlders, 132, 133. 

Glacier Bay, Alaska, 27, 39, 43, 44, 55, 61, 
72, 74, 136, 188, 592. 

Glaciers,ancient, inthe Rocky Mountains, 
176; in the Sierra Nevada, 177 et seq.; in | 
the British Isles, 445, 446, 448 et seq., 483; | 
in Scandinavia, 447; in Germany, 456; — 
in India, 484, 485; in South Africa, 485; | 
in the Andes, 512. 

Glaciers, existing, in the Rocky Moun- 
tains, 13; in the Sierra Nevada, 13 et seq.; 
in southern California, 13; on Mount 
Shasta, 15; on Mount Hood, 19; on | 
Mount Tacoma, 21; on Fraser River, 25; | 


on Stickeen River, 25; in Taku Inlet, | 


27; of Lynn Canal, 27; of Mount St. 
Elias, 30, 600; of Yakutat Bay, 30; of 
Chugateh Alps, 36; of the Alaskan Pe- 
ninsula, 36; in Glacier Bay, 40 et seq.;in 
Greenland, chapter on, 75-102; in Ells- 
mere Land,102;in Grinnell Land, 102;in 
the Alps, 104, 105; in Seandinavia, 104, 
105;in Spitzbergen, Nova Zembla, and 
Franz-Josef Land, 107; in Iceland, 107; 
in Asia, 108; in South America, 108 et 
seq.; in New Zealand, 112; in the Ant- 
arctic Continent, 112 et seq.; in Green- 
land, 602. 
Glaciers, movements oi, 2, 80, 296; semi- 
fluidity of, 3, 4, 81; structure of, 7; slope 
_ of, 18, 47, 77, 78, 85, 88, 95, 108, 198, 201, 
202, 392; velocity of, 3, 54, 78, 80, 82, 105, 
202; thickness of, 19, 22, 47, 77, 79, 81 ,85, 
91, 93, 104, 113, 114, 118, 119, 201, 202, 
Glen Roy, parallel roads of, 364. 
Godfrey’s Ridge, Pa., 197, 247. 
Gould, Dr. D. T., on buried channels in 
Ohio, 304. 
Grafton county, N. H., 330, 331. 
Grafton, W. Va., 370. 
Grand Pacifie Glacier, 73. 
Grand Tower, IIll., 171, 315. 
Granville, Ohio, 564, 603. 
Gravitation of the ocean toward the ice- 


sheet, 503. | 


Gray, Professor Asa, 513; list of Alaskan 
plants identified by, 69;on distribution 
of plants in the northern hemisphere, 
422 et seq. © 

Great Lakes 0” North America, 436; depth 
o ice over, 200,201; erosion in beds of, 260 
et seq.; formation of, 262, 356 et seq., 500, 
501; Newberry on, 262, 356 et seq; pre- 
glacial outlets of, 304 et seq.; glacial 
drainage of, 313, 314, 317, 319; depths of, 
356; influence of ice-barriers on, 390 et 
seq. 

Great Miami River, 170, 300, 301, 323. 326, 
327, 644. 

Great Sait Lake, 336, 607, 609. 

Greeley, A. W., on the Greenland glaciers, 
102. ; 

Green Bay, Wis., 211, °12, 528. 

Green Mountains, 194; terraces on, 30. 

Greenland, the glaciers of, chapter on, 
75-102; area of, 75, 93; interior condi- 
tion of, 75, 84, 447; Nordenskidld on, 77; 
Rink on, 77 et seq.; thickness of ice in, 
77, 79, 82, 85, 201, 202, 503; rate of motion 
of, 78, 80, 82; explorers of 80, Helland on, 
80; subglacial streams of,82, 255; icebergs 
from, 82, 85, 95, 235; Whymper on, 83 et 
seq.; Kane on, 86 et seq., 93 et seqg., 235; 
Hayes on, 89 et seq.; north of 79°, 92; on 
the eastern coast, 97; Nansen on, 98; 
Erichsen on, 99; erosion in, 253, 255, 256; 
Marr on, 366; Preglacial plants of, 424, 
425, 430, 462; Preglacial climate of, 380, 
463; insects of, 439; cause of glaciers in, 
463; during the Glacial period, 527; post- 
glacial elevation of, 507. 

Grinnell Expedition, 86. 

Grinnell Land, glaciers in, 102; post-glae- 
ial elevation of, 583. 

Grooves. See: Rock Scoring. 

Grote, Mr. A. R., on the White Mountain 
butterfly, 439 et seq. 

Ground moraine. See Till. 

Gulf of Mexico, 416, 472. 

Gulf Stream, possible changes in, 495, 508, 
effeet o-, on the Atlantic, 469; cause of, 
470 et seq. 

Guyandotte River, 379, 381, 38°, 604. 


Haenke Glacier, 32. 

Haenke Island, 31. 

Hall, Professor James, 500; on elevation 
of bowlders, 248; on drift hills of New 
York, 286; on rate of recession of Niag- 
ara Falls, 539. 

Hamilton county, Ohio, 242, 602. 

Hamilton, Ohio, 128, 131, 600,644. 


——— ee 
‘- Ko >. 

td 

4 


INDEX. 


Hanover, N. H., 345. 

Hartwig, G.,on glaciers of Magdalena Bay, 
107. 

Haughton, Professor S., on transported 
bowlders in the Hudson Bay region, 245. 

Haverhill Mass., 338. 

Hayes, I., explorations of, in the Saint 
Elias range, 30; in Greenland, 86, 89 et 
seq. 

Haynes, Professor H. W., on palsoliths, 
619 et seg., discovers paleoliths, 628, 629. 

Helland, Mr. A., 445; on rate of movement 
of Greenland glaciers, 80, 82, 202; on 
slope of Jakobshavn glacier, 201; on ero- 
sion in Greenland, 255; in Scandinavia, 
260; on depth of drift in Germany and 
Russia, 260, on formation of cirques, 
274. 

Hennepin discovers Falls of St. Anthony, 
Bar 

Herschel, Sir John, 500. 

Hice, Mr.,309. 

Hicks, Professor, on Raccoon Creek, 56¢, 
565. 

Higginsport, Ohio, 170. 

Highland county, Ohio, 170, 591, 602. 

Hilgard, Professor E. W., 513; on loess, 
410, 411, 415; on depression in Mississippi 
Valley, 410, 411. 

Hillsborough county, N. H.., 330. 

Himalayan Mountains, 108, 365, 427; Qua- 
ternary uplift of, 510, 513. 

Hind, Professor, on glacial drainage, 335. 

Hinde, Dr. G. J., 584. 

Hippopotamus, 690. 

Hitchcock, President E., on size of bowl- 
ders, 236 et seqg.; on the Richmond train 
of bowlders, 239; on kames in Andover, 
Mass., 339. 

Hitchcock, Professor Charles, 504; on ele- 
vation of bowlders, 194, 246, 247; on 
depth of ice, 202; on lenticular hills, 281, 
283, 290, 292; on buried kame in Hano- 
ver, N. H., 345; on Croll’s theory, 574. 

Hocking River, 300, 323, 326. 

Holkham Bay, 27. 

Holmes county, Ohio, terminal moraine 
in, 169; bowlders in, 242; glacial terraces 
in, 326. 

Holst, N. O., 239, 586; on the Greenland 
glaciers, 100, 101. 

Hopkins, Professor W., 497. 

Horse, 436, 438, 690. 

Horseshoe Fall, Niagara, recession of, 540. 

Hudson Bay,199, 246, 354, 356, 607. 

Hudson Bay and Strait, raised beaches of, 
504. 


7ol 


Hudson River, 136, 228, 305, 329, 352, 357, 
358; submarine fiord of, 305, 306, 502, 
503. 

Hugh Miller Glacier, 73. 

Humboldt Glacier, 91 et seq. 

Humboldt Range, 177. 

Hunt, Professor Sterry, on preglacial ero- 
sion, 261. 

Hunter, Captain,on depthof Muir Glacier, 
45. 

Huntingdon Mountain, 148. 

Hurricane Creek, W. Va., 381, 382. 

Hutton, Captain, 510. 


Icebergs, on coast of Alaska, 35; from Muir 
Glacier, 40, 50, 51, 67; from Greenland, 
85, 95; in Straits of Magellan, 111; of the 
Antarctic Continent, 112, 114 et seq.; for- 
mation of, 235. 

Iceberg theory, 126, 133, 143, 183, 200 e¢ seq., 
240. 

Ice, characteristics of, 1 et seg., 232; is but 
compressed snow, 6. 

Iceland, 107, 430, 441, 582. 

Ice-pillars, 10, 49, 70. 

Ice-sheet, advance of, 313; retreat of, 139, 
150, 221, 314, 315, 316, 348, 349, 352, 387 et 
seq., 398, 558, 623, 654, 661; causing de- 
pression of the earth’s crust, 416, 417, 
497,500, 510; probably due to elevation, 
497, 509, 511. 

Icy Bay, 30. 

Tllecillewaet Glacier, 13, 14. 

Illinois, driftless area of, 134; depth of ice 
in, 201; glacial boundary in, 170-172, 525, 
526, 528; bowlders iu, 243; depth of drift 
in, 257; loessin, 415, 587; strie in, 591; 
buried wood in glacial deposits in, 601. 

Illinois River, 314, 354. 

Illinoisan deposits, 223, 590. 

Implement-bearing gravels in Europe, 
616, 624, et seq.; at Trenton, N. J., 630 
et seq., 669, 706; at Madisonville and 
Loveland, Ohio, 644 et seq., 669, 706; at 
Medora, Ind., 649 et seq., 669, 706; at 
Little Falls, Minn., 656 e¢ seq., 669, 706; 
at Claymont, Del., 669 et seq. 

India, 487, 510, 513, 516; glaciers of, 108,365; 
Permian glacial deposits in, 485, 516. 

Indian Ridge in Andover, Mass., 339. 

Indiana, glacial boundary in, 170, 207, 525, 
526, 528; bowlders in, 243, 652; depth of 
drift in, 257, 601, 602; wells in, 300, 601, 
602; loess in, 415, 587; strise in, 591; vege- 
table deposits in, 601, 602, 603; palso- 
lithic implements in, 649 et seq. 

Indianapolis, Ind., 170. 


752 


Insects, migrations of, during the Glacial 
period, 438 e¢ seg.; Alpine species of but- 
terflies upon the White Mountains, 438. 

Interglacial deposits, how preserved, 295 
et seq.; theory of, 576; in Ohio, 592, 598; 
in Minnesota, 605, 607. See Vegetable 
Remains in Glacial Deposits. 

Interglacial epoch, evidence favoring, 575 


et seq., 607 et seq.; duration of, 512, 562, 


563; probable causes of, 497, 512. 

Interglacial man, in France, 616, 623; in 
England, 616, 624; at Trenton; N.J., 625 
et seq.; at Madisonville and Loveland, 
Ohio, 643 et seq.; at Medora, Ind., 649 et 
seq.; at Little Falls, Minn., 653 et seq.; at 
Claymont, Del., 669 et seg.; in Nebraska, 
675; in Tuolumne county, Cal., 689 et 
seq.; Le Conte on, 688 et seg., 699; Daw- 
kins on, 699. 

Interglacial migrations from Africa to 
Europe, 507. 

Interior moraines, 140, 204, 207 et seq. 

Interior, probable condition of the earth’s 
498, 502, 518. 

Towa, 362, 525, 528, 661; driftless area of, 
134, 414; depth of ice in, 201; bowlders in, 
243; lakes in, 361; loessin, 413-416; veg- 
etable deposits in, 605. 

Iowan deposits, 223. 

Treland, 11, 339, 360, 361, 445, 446, 448. 

Trish Sea Glacier, 446, 449-451. 

Isblink, 79. 

Italy, xlaciation in, 486, 


Jackson county, IlJ., 171, 172, 243. 

Jackson county, Ind., 170, 601, 649. 

Jackson, Dr. Sheldon, on depth of Muir 
Glacier, 45. 

Jackson, Mr. C. T., cited, 331. 

Jacobus Creek, 352. 

Jakobshavn Glacier, 78, 80; rate of dis- 
charge, 82, 85; slope of, 201,202; subgla- 
cial streams of, 255; glacial damsof, 366. 

Jamaica, post-glacial elevation of, 507. 

James, Professor Joseph F., on buried 
channels in the Ohio, 301. 

James River, Dakota, 214, 215, 336. 

Jamieson, T. F.. 498, 500, 501. 

Japan, flora of, 423, 426, 431, 4382, 434; dust- 
fog in, 409. 

Jefferson county, Ind., 602. 

Jennings county, Ind., 601. 

Jensen, A.D., 80, 81, 201. 

Johns Hopkins Glacier, 73. 

Johnson, Dr. L., on drumlinsin New York, 

286, 291. ‘ 
Johnsonville, Pa., 352. 


INDEX. 


Jones, Dr., 701. 
Jtivdliarsuk Glacier, 79. 
Juneau, Alaska, 27, 59. 


Kamchatka, 480, 441. 

Kames in Rindge, N. H., 330; in Winchen- 
don, Mass., 330; chapter on, 339-354; Ed- 
ward Hitchcock’s description of, 339; J. 
Geikie’s description of,339; structure of, 
340; compared with terminal moraines, 
340; theory of, 11, 16, 66, 341; forming 
at the Muir Glacier, Alaska, 66, 342; sys- 


tem of,in New England, 342; buried, 345; - 


in the Connecticut Valley,345; Dana on, 
346, 347; at Stroudsburg, Pa., 348, 352; 
deltas of, 348, 352; in Rangely Lakes, 
349; location of, prognosticated, 349, 350; 
of backward drainage, 350 et seq.; in 
Schoodic Lake, 350; near Ossipee Lake, 
351; near Portland, Pa., 352; near the 
Finger Lakes, N. Y., 352; in Ohio, 353; 
absence of, in the Northwest, 353; com- 
pared to a skeleton, 354. 

Kanawha River, 300, 309, 379, 381, 383, 604. 

Kane, Dr., explorations of in Greenland, 
86, 87, 92 et seq.; on formation of icebergs, 
2352 

Kansan drift, 158, 154, 158, 224, 585, 588. 

Kansas, glacial boundary in, 172; loess in, 
414, 415. 

Kansas City, Mo., 172, 412. 

Kansas River, 172, 414. 

Karajak Glacier, 78. 

Keewatin ice center, 585, 586. 

Kelley’s Island, 262. 

Kenai Peninsula, glaciers on, 36. 

Kennebec River, 221, 342. 

Kenton county, Ky., 367. 

Kentucky, 170, 201, 243, 367, 368, 375, 385, 
386, 487. 

Kettle-holes, defined, 11; formation of, in 
front of Muir Glacier, 57, 66; in Ply- 
mouth county, Mass., 139, 360; explan- 
ation of, 143; resemble sink-holes, 148; 
formation of, 144, 204, 359, 360, 572; 
on Pocono Mountain, 148; near Ack- 
ley, Pa., 150; in Ohio, 168, 169, 597; abun- 
dance of, in terminal moraine, 204, 360, 
361; Professor Koons on, 204 et seq.; direc- 
tion of longer axis of, 204, 205; in New 
England, 360, 361; age of, estimated, 572 
et seq.; near Freehold, Pa., 598. 

Kettle Range, Wis., 134, 144, 207, 211, 212, 
221, 361, 415, 527. 


' King, Mr. Clarence, 498; on glaciers of 


Mount Shasta, 15 et seq.; discovers ter- 
minal moraine, 134, 221; report on forti- 


.; i x —e— Le ail 


INDEX. 


eth parallel, 177 et seg.; on Yosemite | 
Valley, 271; on drumlins, 288; on dust- 


fogs, 409. 

Kinnahan on drumlins, 290. 

Kittatinny Mountain, 133, 146, 228; eleva- 
tion of bowlders on, 196, 247 et seq.; ero- 
sion on, 260. 


Knox county, Ohio, glacial boundary in, | 


169; buried channel in, 301; terraces in, 
326. 3 


Koldewey, Captain, on east coastof Green- | 


land, 98. 

Koons, Professor B. F., on kettle-holes, 
204 et seq. 

Kryokonite defined, 9. 

Kuro-Siwa, 495. 

Kurtz, Mr. M. A., 701. 

Kuskovim River, 36. 


Labrador, depth of ice in, 202; insects in, | 


439-441; acenterofshow-fall, 527,585,586. 

Lake Agassiz, 401 et seq., 559, 654, 655; delta 
terrace in, 334; beaches of, 401, 404 e¢ seq., 
500, 543, 545, 655, 664; vegetable deposits 
in bed of, 603, 607; Upham on, 401 et seq., 
543 et seq. 

Lake Allegheny, 158-160. 

Lake Arikaree, 336. 

Lake Bonneville, 336, 609, 611, 622, 704. 

Lake Calhoun, 555. 

Lake Champlain, 358, 363. 

Lake Chautauqua, 308, 363. 


Lake Erie, 201, 354, 395, 542; islands of, 262 | 
et seq.; preglacial outlet of, 303 et seq., 536; 


glacial drainage of, 314, 317;formationof, 
356 et seq., 363; beaches of, 545. 

Lake Harriet, 555." 

Lake Huron, 201, 367, 542; preglacial out- 
let of, 304 et seq.; glacial drainage of, 314, 
317; origin of, 356, et seg. 

Lake Humber, 448, 451, 452. 

Lake Itasca, 655. 

Lake Lahontan, 608 e¢ seq., 612. 

Lake Lesley, 156. 

Lake Lindeman, 29. 


Lake Michigan, 211, 306, 354, 361, 525, 528, — 


665; preglacial outlet of, 305, 306; glacial 


drainage of, 314; origin of, 356 et seq.; | 


dunes of, 545; post-glacialerosionin, 571. 

Lake Minnetonka, 211, 212, 361. 

Lake Mono, Cal., 273, 607. 

Lake Nipissing, 542. 

Lake Ontario, 148, 395, 398, 536, 587; pre- 
glacial drainage of, 304 et seq.; origin of, 
356 et seq. 

Lake ridges, around Erie, 395, 397; around 
Ontario, 395. 


753 


Lake Superior, 199, 201, 212, 213, 325, 367, 
528, 664; preglacial outlet of, 305, 306; 
glacial drainage of, 314; origin of, 356 et 
seq,; Vicinity of, acenter of snow-fall, 527. 

Lake Traverse, 316, 354. 

Lake Washington, 181. 

Lake Williams, 153, 154. 

Lake Winnepesaukee, 221, 363. 

Lake Winnipeg, 654, 655. 

Lakes formed in mountain-building, 510, 
Pe: 


‘Lamoile River, 347. 


Lamplugh, G. W., 505, 587. 

Lang, Mr. C., 105. 

La Pérouse, 42, 43. 

Lattas, Ohio, 602. 

Laurentian lakes, basins of the, 500, 501. 

Laurentian Mountains, 199, 244, 246, 259, 
357, 527. 

Lava-beds in western United States, 417, 
418. 

Lawrence county, Pa., 326. 

Lawrence, Mass., 348, 350. 

Lawrenceburg, Ind., 326, 327. 

Le Conte, Professor Joseph, 498, 501, 507; 
on succession of glacial epochs, 490; on 
deep placer deposits in California, 688 
et seq. 

Lebanon Mountains, glaciers of, 612 e¢ seq. 

Lehigh River, 325, 637. 

Lehigh Water-Gap, 197. 

Lenox, Mass., train of bowlders in, 239, 240. 

Lesley, Professor J. P., on depth of the ice, 
195-197; on elevation of bowlders, 195, 248 
et seq.;on depthof drift in, 259; onerosion 
in northern Pennsylvania, 260; on Cin- 
cinnati ice-dam, 371. 

Lesquereux, Leo, on rate of accumulation 
of peat, 594 et seq.; cited, 690. 

Leverett, Mr., on the Kanawha, 309; corre- 
lates Alpine episode with American, 580; 
on age of Kansan till, 588. 

Lewis, Professor H. Carvill, 619, 628, 629, 
637; begins the survey of Pennsylvania, 
135, 148, 149; discovers moraine on Pocono 
Mountain, 147;0n transportation of bowl- 
ders, 197, 247 et seq.; on depth of ice in 
eastern Pennsylvania, 197; on erosion in 
nortbern Pennsylvania, 260; reports 
drumlins in Pennsylvania, 287; on mar- 
ginal kames in eastern Pennsylvania, 
352; on glaciated area of Great Britain, 
448, 449 et seq.; on kettle-hole at Free- 
hold, Pa., 598; the Philadelphia red 
gravel and brick-clay of, 637, 671. 

Lewiston, Me., 343. 

Licking county, Ohio, 169, 564, 603. 


154 _ INDEX. 


Licking River, Ky., 310, 367, 385-387. 

Licking River, Ohio, 300. 

Lindenkohl, A., 502. 

Little Falls, Minn, 619, 653 et Seq. 

Little Falls, N. Y., 329. 

Little Miami River, 327, 643, 644, 645. 

Little Sandy River, 19. 

Little Scioto, 309. 

Lituya, 42, 43. 

Lituya Bay, Alaska, 74. 

Llama, 436, 437. 

Loess, 172, 256, 685; chapter on, 407-420; 
Pumpelly on, 407, 408; composition of, 
407, 412; in China, 408, 513; Baron Richt- 
hofen on, 408; in Europe, 410, 512; in 
America, 410; Hilgard on, 410, 411; alti- 
tude of deposits of, 410, 413, 416; Cham- 
berlin on, 412; theory of, 413 et seq., 588; 
extent of subsidence indicated by, 413, 
416; Upham on, 415; earthworms and 
the, 418; in Ohio, 644. 

Logan, Sir William, 570. 

Long Island, terminal moraine on, 140, 144, 
204, 207; bowlders on, 238; over-wash 
gravel on, 349; kettle-holes on, 360. 

Long Level, W. Va., 381, 604. 

Long, Mr., on Paint Creek, 562. 

Lorain county, Ohio, 395. 

Lorange, on cirques, 274, 276. 

Louisville, Ky., 170, 300. 

Loveland, Ohio, palzolithic implements 
found at, 643, 645. 

Lowell, Mass., 343-345. 

Lubbock, Sir John, 624. 

Luzerne county, Pa., 148. 

Lycoming county, Pa., kettle-holes in, 149; 
terminal moraine in, 149; bowlders in, 
242. 

Lycoming Creek, 149, 325. 

Lyell, Sir Charles, 497, 509; observations 
of, in Nova Scotia, 126,127; on Richmond 
train of bowlders, 239, 240; theory of the 
cause of the Glacial period, 495; principle 
of uniformity, 533; on rate of recession 
of Niagara Falls, 539, 706; on antiquity 
of man, 616, 624. ; 

Lynn Canal, Alaska, 27, 43, 59, 61, 188. 


Machias River, 342, 343. 

Mackenzie River, 246. 

Mackintosh, Mr., 570. 

Macoun, Professor, cited, 569. 

Madison, N. H., bowlder in, 238. 

Madisonville, Ohio, paleolithic imple- 
ments found at, 643, 644. 

Magdalena Bay, 107. 


Maine, 137, 441, 665; depth of ice in, 194, 
195; bowlders in, 247; depth of drift in, 
259; absence of drumlins of large size in, 
286; kames in, 349-351, 353; lakes in, 361; 
marine beds overlying glacial drift, 504. 

Malaspina Glacier, 30, 31, 32, 606. 

Mammoth, 438, 586, 690. 

Mammoth Cave, 229. 

Man, antiquity of, in America, 438, 534, 
639-640; and the Glacial period, chapters 
on, 616-709. . 

Manchuria, 427, 432. 

Mandan, 430. 

Manitoba, 335, 354. 

Manomet Hill, 139. 

Marginal drainage, 175, 333 er seq., 351, 352. 

Marietta, Ohio, 323, 327. 

Marine shells, elevation of, in glacial de- 
posits in Wales, 453; near Boston, 453. 
Marr, Mr. J. E., on erosion in Greenland, 

256, on glacial dams, 366. 

Marshall, Ohio, 602. 

Martha’s Vineyard, 187, 144, 203, 237. 

Martinsville, Ohio, 309. 

Marvine Glacier, 32. 

Mary Minturn River, 92. 

Massachusetts, terminal moraines of, 137, 
139; depth of ice in, 195; depth of drift 
in, 259; transported bowlders in, 238, 
239, 240; drumlins in, 283-285, 288; kames 
in, 330, 353; kettle-holes in, 360, 361, 575; 
lakes in, 361. 

Mastodons, 436, 437, 586, 639, 645, 675, 690. 

Mattawa River, 542, 543. 

Mattawamkeag, Me., 343. 

Mattawan, Can., 542, 543, 548. 

Mattison, Mr., 700, 761. 

Mattmark, Sea, 365. 

Maumee River, terminal moraine in valley 
of, 207 et seq., 266. 

McConnell, Mr. R. G., on the Cypress 
Hills, 199, 200; on depth of drift in Brit- 
ish America, 259. 

McGee, Mr. W J, 512; Columbia period 
of, 613, 639, 671. 

McKeesport, Pa., 379. 

Medial moraines, east arm of Kettle Range, 
a, 211; Coteau des Prairies, a, 214. 

Medial moraines, formation of, 9; of Muir 
Glacier, 48, 49, 236; of White River Glac- 
ier, 22. 

Mediterranean Sea, 433. 

Medlicott and Blandford on signs of glac- 
iation in India, 484, 485, 510. 


Medora, Ind., paleolithic implements 


found at, 649 et seq. 
Megalonyx, 436. 


* Ady a 


INDEX. 


Megatherium, 436. 

Melville Bay, 92. 

Mer de Glace of Switzerland, 3, 4, 10; of 
Greenland 87, 89, 90. 

Merjelen Sea, 364. 

Merrimack River, 330, 331, 348, 344, 350, 
660. 

Mesozoic era, absence of glacial epochs 
during the, 515, 518. 

Metuchen, N. J., 142. 

Metz, Dr. C. L., finds palzolithic imple- 
ments at Loveland and Madisonville, 
Ohio, 619, 642, 644, 645. 

Michigan, buried channel in, 306; salt 
deposits of, 464. 

Middle Bass Island, 262. 

Migrations of plants and animals, 422, et 
seq., 506, 513, 665. 

Milan, Ind., 602. 

Milk River, 334. 

Mill Creek, 300, 301, 393, 643, 644. 

Minneapolis, Minn., 211, 212, 303, 315, 
361, 552, 554, 655, 660. 

Minnesota, driftless area of, 134; depth of 
icein, 201; terminal moraines in, 211-213, 
525, 613, 655, 661 et seq.; varieties of drift 
in, 213; depth of drift in, 258, 555; drum- 
lins absent in, 287; waterfalls in, 303, 552 
et seq.; delta terraces in, 334; occasional 
kames in, 353; lakes of, 361; loess in, 416; 
preglacial man in, 438, 653 et seg.; post- 
glacial erosion in, 552 et seq.; buried chan- 
nel in, 553 et seg.; wells in, 555, 605, 607; 
vegetable deposits in, 605; palzolithic 
discoveries in, 619, 653 et seq. 

Minnesota River, 214, 315, 316, 336, 354, 361, 

M362, 554-556, 558, 559. 
ississippi River, 136, 171, 203, 354, 357, 
358, 361, 389, 417, 527, 634, 655, 656, 665; 
preglacial channels of, 311; preglacial 
erosion of, 228, 298, 315, 496; loess of the 
valley of, 256, 410 et seq., 415; glacial drain- 

_ age of, 313, 314; terraces on, 315, 415, 558, 
654; post-glacial erosion in, 315, 552 et seq., 
665; rate of transportation by the, 562. 

Missouri coteau in British America, 135, 
176, 217 et seq.; source of, 244. 

Missouri coteau in Dakota, 215, 217, 332, 
333. 

Missouri, glacial boundary in, 172, 415; 
bowlders in, 243. 

Missouri River, 172-175, 215, 220, 243, 244, 
320, 321, 336, 414-416. 

Mohawk River, 195, 228, 303, 305, 314, 319, 
352, 353, 587; ice-dam in, 398, 536, 539. 

Mohawk Valley, 542. 

Mohegan Rock, Conn., 238. 


750 


/ Mono county, Cal., 13, 222. 


Monongahela River, 300, 308, 370, 372, 377, 
378, 384, 604; ice-dam in, 391-393. 

Monroe county, Pa., terminal moraine in, 
146, 148; depth of ice in, 195, 198; buried 
channels in, 311. 

Montana, former glaciers in, 13, 176;glacial 
boundary in, 133, 175; bowlders in, 243. 

Mont Blane, 104, 109. 

Montgomery county, Ohio, organic re- 
mains in glacial deposits in, 592, 593; 
depth of till in, 592. 

Montreal, marine beds overlying glacial 
drift, 504; depression at, 542. 

Moose, 675. 

Moraines, formation of, described, 9. 

Moraines of retrocession, 57, 207, 222, 223. 

Moreau River, 174, 175. 

Morgan county, Ind., 601. 

Morgantown, Ind., 601. 

Morgantown, W. Va., 370, 377, 378, 603. 

Morris county, N. J., 241. 

Morrison county, Minn., 653, 655. 

Morse Glacier, 72. ; 

Moulins defined, 9; on Mount Tacoma, 22; 
on Muir Glacier, 48. 

Mountain-building, probably correlated 
with epochs of glaciation, 499, 502, 507, 
509 et seq. 

Mount Baker, 23, 180, 192. 

Mount Crillon, 42, 43, 68. 

Mount Dana, 15. 

Mount Desert, Me., 137, 194, 195. 

Mount Fairweather, 35, 42, 43, 68. 

Mount Hood, 19, 192. 

Mount Jefferson, 19. 

Mount Katahdin, Me., 195, 247, 348, 441. 

Mount Kelertingouit, Greenland, 85, 86. 

Mount McKinley, 36. 

Mount Lyell, 15, 269, 273. 

Mount Rainier. See Mount Tacoma. 

Mount Shasta, 15 et seq., 192. 

Mount St. Elias, 30, 34-36, 42. 

Mount Tacoma, 21, 136, 180, 192, 193. 

Mount Washington, 194, 246, 439-441. 

Mount Wrangel, 36. 

Mower county, Minn., 605. 

Mud River, W. Va., 381. 

Muir Glacier, cross-section of, 4, 39; kames 
forming in, 11, 66, 342; discovery of, 39; 
chapter on, 40-74; accessible to tourists, 
40; difficulties of measurement, 41, 52; 
surrounding mountains, 41-43; vegeta- 
tion in the vicinity of, 41, 57; view of, 42; 
former extension of, 43, 59, 189; relation 
to Glacier Bay, 45; width of, 45; terminal 
moraine of, 45, 57; transported bowlders 


756 INDEX. 


on, 45, 236; thickness of, 47, 234; slope of, 
47; extent of, 47; moulins of 48; nunataks 
of, 47, 79, 189; medial moraines of, 43, 49, 
56, 236; ice-pillars of, 49; surface of, 50; 
front of, 50; icebergs from, 50, 51, 67; 
subglacial streams of, 51, 55, 57, 61, 66 ez 
seq., 342; buried forests near the, 53, 61 
et seq., 233, 592; velocity of, 55, 80; daily 
discharge of, 55, 82; view of surface of, 56; 
kettle-holes in front of, 57, 58, 66, 144, 204; 
retreat of, 57; former extent of, 59; Van- 
couver on, 59; view of stumps of cedar 
trees 62, 63; movement over gravel de- 
posits, 66, 233; sediment, 68; temperature 
near, 69; Professor Reid on, 71, 72. 


Muir Inlet, 41, 45, 189, 192; list of plants” 


about, 69. 
Muir, Professor, explorations in Alaska, 
39, 68. 
Muskingum River, 300, 314, 323, 327. 
Musk-ox, 675. 
Mylodon, 436. 


Naaman’s Creek, 675. 

Nampa image, 701 et seq. 

Nansen, Dr. F., on Greenland, 98. 

Nanticoke, Pa., 332. 

Nantucket, 137, 139, 203. 

Natal, Permian glacial deposits in, 516. 

Naushon, 204 e¢ seq. 

Nebraska, glacial boundary in, 172; bowl- 
ders in, 243; loess in, 411, 414, 415, 587. 

Nelson River, 313. 

Nevada, former glaciers in, 176; salt lakes 
in, 607. 

Névé field, in Greenland, 88; on the Sierra 
Nevada, 18, 179, 273 

‘New Alexandria, Ohio, 168. 

Newark, Ohio, 169, 326. 

Newberry, J. S., 487; on glaciers of Cascade 
Range, 19; on depth of glacial deposits, 
257; on glacial erosion, 261; on formation 

_of the Great Lakes, 262, 356 e¢ seq.; on 
buried channels in Ohio, 300, 301; on pre- 


glacialdrainage through Ontario, 305,306. 


‘New Burlington, Ohio, 602. 

Newburyport, Mass., 343. 

Newcomb, Professor Simon, 192, 476. 

Newcomerstown palzolith, 645 et seq. 

New England, 139, 358, 398, 487, 523; glacial 
drainage of, 136; kettle-holes in, 139, 360, 
361; depth of ice in, 194, 195, 201; termi- 
nal moraines of, 134, 203, 361; transported 
bowlders in, 237, 238, 239, 240; depth of 
drift in, 259; glacial drainage in, 330, 331, 
342, 343; kames in, 330, 343 et seq.; lakes 
in, 361, 363; peat-bogs, 360. 


New Hampshire, 139,665; depth of icein,194 
transported bowlders in, 194, 237, 246; 
terminal moraines in, 221; depth of till 
in, 259; drumlins in, 283, 285, 288; delta 
terraces in, 330; kames in, 340, 341; lakes 
in, 361, 363, 

New Harmony, Ind., 170, 326. 

New Jersey, terminal moraine in, 133, 134, 
140, 142, 144, 151, 206; depth of ice in, 198; 
transported bowlders in, 241; lakes in, 363; 
interglacial man in, 438 palzolithie dis- 
coveries in, 619, 620, 625 et seq. 

New Mexico, 274. 

New Richmond, Ohio, 367. 

New York, 317, 398, 665; glacial boundary 
in, 133, 525; depth of ice in, 195, 261; ter- 
minal moraine in, 149, 206; bowlders in, 
242; drift hills in, 286; buried channels 
in, 305, 306, 307, 308; kames in, 352, 353; 
lakes in, 363; lake ridges in, 395; salt de- 
posits in, 463. 

New York Central Railroad, terraces 
along the, 329. 

New York City, 357, 398, 502. 

New Zealand, glaciers in, 104, 112, 488, 510; 
cirques in, 274. 

Niagara gorge, length of, 299, 353, 376, 536; 
a glacial chronometer, 299, 536 et seq., 
548-552; erosion of, 542; recession of at 
standstill, 543. 

Niles, Professor, on erosion by the Aletsch 

Glacier, 231, 232. 

Niobrara River, 172. 

Nisqually River, 21. 

Nittany Valley, Pa., 229, 230. 

No Man’s Land, 137. 

Nordenskiéld, A. E., 518; on influence of 
meteoric dust,9;expedition to Greenland, 
75 et seq.; on subsidence of Sahara, 433. 

Northampton county, Pa., terminal mor- 
aine in, 146. 

North Bass Island, 262. 

North Bay, Can., 548. 

North Bend, Ohio, 170, 367. 

North Carson Lake, Nevada, 607. 

Northern Pacific Railroad crosses the gla- 
cial boundary, 174, 175, 213. 

North Sea Glacier, 446, 449. 

Norway, glaciers of, 104, 106, 110, 232, 234, 
445; erosion in, 278; depth of ice in, 447. 
Nova Scotia, 126, 127; absence of Quater- 
nary marine beds in, 504. 

Nova Zembla, 107, 488. 

Nunataks, 47, 79, 189, 254, 366. 


Oahe, Dakota, 174. 
Oberlin, Ohio, 565. 


j 


INDEX. 


Ocean lowered to supply ice, 503; raised by | 


ice attraction, 503. 
Ohio, fringe in, 167; terminal moraine in, 
168 et seq., 198, 372; kettle-holes in, 168, 


169; wells in, 168, 169, 257, 258, 602; bowl- | 


ders in, 242, 243; depth of till in, 257, 258, 


592, 593, 598-600; preglacial erosion in, | 
299, et seqg.; buried channels in, 300 et seg., | 
304, 644; glacial drainage in, 314; absence | 


of terraces in unglaciated part, 323; 
kames in, 353; limit of glacier in, 357, 
358; glacial erosion in, 358; glacial 


boundary in, 367, 525, 526; lake ridges | 


in, 395 et seq.; interglacial man in, 438, | 
640 et seqg.; post-glacial erosion in, 560; | 


strie in, 591; vegetable deposits in, 592, 
. 593, 598 et seg., 602, 
paleolithic implements in, 642 et seq. 


603; loess in, 644; 


Ohio River, 170, 208, 228, 353, 358, 634, 643; | 
glacial drainage of, 314, 353; preglacial | 


drainage of, 309, 310; occupies a pregla- | 
cial gorge, 299 et seqg., 384; glacial dam | 


in, 366, et seq; terraces on, 370 et seq. 
Oil Creek, Pa., 326. 
Okhotsk-Kamchatkan region, flora of, 
441-444, 
Olympian Mountains, 180, 192. 
Ontario, Can., 665. 


Oregon, 222, 417, 426; glaciers in, 19, 177, | 


191, 192, 607. 
Oregonia, O., limestone bowlder in, 239. 
Orton, Professor Edward, on bowlder at 
Oregonia, O., 239; on depth of till, 257; 


on buried channels in Ohio, 302; on | 
Paint Creek, 560; on vegetable deposits 


in Ohio, 592, 602. 
Osage River, 321. 
Oscillations of land and sea, 497 et seq. 
Ossipee Lake, 351. 
Ottawa Valley, 542, 543. 


Over-wash gravel, 204, 348 et seg. See | 


Delta Terraces and Kames. 

Owen, Miss, finds implement at St. 
Joseph, Mo. 

Oxford, Ohio, 600. 

Oysters, 586. 


Packard, Prof. A. S., 504; reports trans- 
ported bowlders on Mount Katahdin, 
Me., 247. 

Paint Creek, 326, 372 et seq., 384, 560 et seq. 

Palezoliths, characteristics of, 616 et seq.; 
Haynes on, 619 e¢ seg.; oceurrence of, 
in glacial gravels in France and England, 
623-625; at Trenton, N. J., 625 et seq.; at 
Madisonville and Loveland, Ohio, 642 
et seq.; at New Comerstown, Ohio, 645 


757 


et seq.; at Medora, Ind., 649 et seg.; at 
Little Falls, Minn., 653 et seg.; at Clay- 
mont, Del., 669 e¢ seq. 

Palestine, Ohio, 168. 

Panama, Isthmus of, Quaternary oscil- 
lations of, 568. 

Paris Crossing, Ind., 602. 

Parker Creek, 15. 

Parker, Pa., 604. 

Passadumkeag, Me., 343. 

Patagonia, 104, 488. 

Patterson Glacier, 27. 

Patton, Rev. J. L., 40. 

Payer, Mr., on east coast of Greenland, 
98. 

Peabody Bay, 92. 

Peary, R. A., 99, 100. 

Peat-beds, formation of, 360, 594 et seq.; 
age of, 573, 574, 597, 598; in New England, 
360; in southern Ohio, 592, 593; in Penn- 
sylvania, 598; in Minnesota, 605. 

Peekopee Lake, 334. 

Pelee Island, 262. 

Pelican Lake, 334. 

Pembina River, 333, 334. 

Penck, Dr. A., on cirques, 275, 278; on Al- 
pine glaciers, 459; on oxidization, 580. 

Pendelton county, Ky., 170. 

Pennsylvania, 436, 487; terminal moraines 
in, 133, 146 et seq., 206, 376, 526; kettle- 
holes in, 148, 598; fringe in, 153, 167; trans- 
ported bowlders in, 241, 242; terraces in, 
150, 370-372, 375, 379, 384; depth of ice in, 
195 et seq.; direction of strize in, 248, 249; 
depth of till in, 259; glacial erosion in, 
260; wells in, 260, 604; few drumlins in, 
287; buried channels in, 307, 308, 332; 
kames in, 348, 352; marginal drainage in, 
352; vegetable deposits in, 604. 

Penobscot River, 342, 343. 

Percival on drumlins, 285. 

Permian glacial epochs, 484, 485, 509, 515, 
518. 

Perry county, Ohio, 169, 326. 

Perth Amboy, N. J., 140. 

Perthes, Boucher de, palezolithic discover- 
ies of, in France, 574, 623, 624. 

Peru, post-glacial elevation of, 507. 

Petermann Peak, 98. 

Philadelphia, 671; and vicinity, preglac- 
ial elevation of, 502. 

Philadelphia red gravel and brick-clay, 
634 et seq., 636, 671, 673. 

Pickaway county, Ohio, 169. 

Pike county, Ohio, 372 et seq., 374. 

Pike county, Pa., 205. 

Pilgrim Fathers, 137. 


758 


Pipestone county, Minn., 353. 

Piscataqua River, 342, 352. 

Pittsburgh, Pa., 370, 375, 384. 

Plainfield, N. J., 140, 142. 

Plains, the Western, uplifted in the Qua- 
ternary period, 502. 

Plants, in the clay deposits of the Monon- 
gahela, 392; migrations of, during the 
Glacial period, chapter on, 422-444; pre- 
glacial distribution of, 422, 430; Professor 
Asa Gray on, 422 et seq.; resemblance of, 
in Japan and eastern North America, 
423, 432; manner of migration of, 424; of 
the Pacific coast of North America, 426, 
435; of Japan and North China, 427, 434; 
of Europe, 427; of the Tertiary period, 
428, 430; effect of Glacial period upon, 
429, 431, 433; the birthplace of, 432; on 
oceanic islands, 436; list of, common to 
the Okhotsk-Kamchatkan region and 
North America, 441-444. 

Platte River, 172, 177, 414, 416. 

Plum Creek, Ohio, 565-568, 575. 

Plum Island, 140. 

Plymouth county, Mass., 137, 139, 360. 

Plymouth Rock, Mass., 238. 

Pocatello, Idaho, 337. 

Pocono Mountain, terminal moraine on, 
133, 146, 148, 526; depth of ice over, 198; 
bowlders on, 241. 

Pohlman, Dr., on the Niagara gorge, 540. 

Point Pleasant, Ohio, 36. 

Point Wilson, state of Washington, 182. 

Polar ice-cap, 179, 192. 

Pomp’s Pond, Andover, Mass., 572: et seq. 

Port Foulke, 89, 92. 

Port Jervis, 314. 

Port Townsend, 180, 182. 

Portland, Me., 349. 

Portland, Ore., 21, 39, 40, 135. 

Portland, Pa., 352. 

Post-glacial erosion, 590; in gorge of Niag- 
ara, 269, 536 et seq.; of Mississippi, 315, 552 
et seq.; of Paint Creek, 561, 562; in Rac- 
coon Creek, Ohio, 564, 565; in Plum 
Creek, Ohio, 565-568; in Lake Michigan, 
571. 

Post-glacial oscillations of level, 504-506. 

Pot-holes, in Grafton county, N. H., 331; 
in Lackawanna county, Pa., 332; at Mat- 
tawan, Can., 543. 

Potomac River, 671. 

Potter county, Pa., terminal moraine in, 
149; depth of ice in, 195. 

Powell, Major J. W., 498. 

Pratt, Archdeacon J. H., 497. 

Precession of equinoxes, 467, 468, 509, 511. 


| 


INDEX. 


Preglacial climate, 463. 
Preglacial drainage, chapter on, 298-312; 


lower levels of, in the Ohio Valley, 300 
et seq.; erosive effect of, 300; buried chan- 
nels of, 301 e¢ seqg.; in the vicinity of Cin- 
cinnati, 301; in central Ohio, 302; in the 
vicinity of Minneapolis, 303; between 
Lakes Erie and Ontario, 303; in southern 
tributaries to Lake Erie, 304; between 
Lakes Huron and Ontario; 304; in the 
Mohawk Valley, 305; in Illinois, 306; in 
western Pennsylvania and western New 
York, 307, 308; in eastern Pennsylvania, 
311; in the Province of Quebec, 312. 

Preglacial elevation, 502. 

Preglacial erosion, extent of, 226 et seq., 261, 
279, 298 et seq., 353, 540, 542, 562, 564. 

Preglacial terraces, 372. 

Preglacial topography, 590. 

Preglacial weathering of strata, 513. 

Prehistoric woodenstructures of Naaman’s 
Creek, 675. 


Prestwich, Professor Joseph, 498, 511, 514, - 


517, 624; on length of Glacial period, 613 
et seq. 

Prince William Sound, 36. 

Provincetown, Mass., 137. 

Puget Sound, 136, 176, 180, 192, 193. 

Pumpelly, Professor Raphael, 513, 517; on 
preglacial erosion, 261, on loess, 407 et 
seq. 

Putnam county, W. Va., 379, 604. 

Putnam, Professor F, W., 642; on his dis- 
coveries of paleolithic implements, 627; 
on antiquity of man in California, 698, 
699. 

Puyallup River, 21. 

Pyramid Lake, Nev., 607. 

Pyrenees, 429, 433, 436, 449; ancient glaciers 
in, 512. 


Qu’Appelle River, 333, 335. 
Quebec, Province of, 570. 
Queechee, Vt., 247. 

Queen Charlotte Islands, 506. 
Queen Inlet, 73. 

Queenston, Can., 536 et seg., 550. 


Raccoon Creek, Ohio, 324, 564, 575, 603. 

Ramsay, Sir A. C., theory of rock basins, 
269; on early glaciation, 483 et seq. 

Randolph, N. Y., 149. 

Rangeley Lakes, 342, 349. 

Ravenna, Ohio, 353. 

Read, Mr. M. C., on buried channels in 
Ohio, 301. 


4 


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: 
. 


INDEX. 


Recession, rate of, of falls of Niagara, 536 
et seq.; Falls of St. Anthony, 552 et seq.; 
falls in Black River, Ohio, 560; of trib- 
utary to Paint Creek, 561, 562. 

Red Bank, Ohio, 644. 

Red River of the North, 199, 220, 258, 316, 
333, 334, 354, 361, 607, 654. 

Red River Valley, 548. 

Reid, H. F., 71, 72. 

Reid Glacier, 73. 

Reid Inlet, 73. 

Reindeer, 641, 675. 

Rendu Glacier, 73. 

Rensselaer Harbor, 89. 

Revillo Gigedo Island, 188. 

Rhine River, 410, 412, 447. 

Rhinoceros, 586, 690. 

Rhode Island, terminal moraine in, 140, 
204; depth of drift in, 259. 

Rhone Glacier, 255. 

Richardson , Mr. James, 187, 188. 

Richardson, Sir J., on transported bowl- 
ders in the Mackenzie Valley, 246. 

Richmond, Mass., train of bowlders in, 
239-241. 

Richthofen, Baron, 513, 517; on loess, 408, 
409. 

Ricketts, Dr. Charles, 508. 

Riggs, Rev. Thomas L., 175. 

Rink, H., on results of Greenland explor- 
ation, 77 et seq. 

Ripley county, Ind., 602. 

Ripley, Ohio, 170, 367, 526. 

River that turns, 335. 

Riviére des Lacs, 334. 

Roches moutonnées, 84, 183, 185, 187, 227, 
231, 295, 483. 

Rock-basins in the Sierra, 267 et seq., 355. 

Rock-scoring in Glacier Bay, Alaska, 44; 
described, 123 et seg.; near Victoria, Van- 
couver Island, 183 et seg.; on islands in 
Lake Erie, 262 et seg.; on the Sierra, 267 
et seq.; in South Africa, 485. 

Rocky Mountains, 13, 14, 200, 244, 273, 
415-417, 429, 441, 462, 607; ancient glaciers 
in, 175-177, 512; Quaternary uplifts of, 
502, 507, 511, 512. 

Rocky River, 304. 

Rome, N. Y., 542, 587. 

Ross county, Ohio, 372; terminal moraine 
in, 169, 170; transported bowlders in, 169, 
242; vegetable deposits in, 602. 

Ross, Sir J. C., explorations of, in Ant- 
arctic Continent, 112 et seq. 

Russell, Mr. I. C., on glaciers of the Sierra 
Nevada, 179; on moraines of Monocoun- 
ty, Cal., 222; on glacial erosion, 267; on 


759 


Yosemite Valley, 271; on cirques, 271 et 
seq.; on Lakes Lahontan and Bonneville, 
608, 610; on gravel deposits about Dead 
Sea, 612. 

Russell Fiord, 31, 32. 

Sabine, E., explores east coast of Green- 
land, 98. 

Saco River, 221, 342, 351. 

Saguenay, fiord of the, 501. 

Sahara, Desert of, 433, 496. 

Salamanea, N. Y., 586. 

Salisbury, Professor R. D., 501; on loess, 
172; discoveries in northern Germany, 
452,456; on deposits in New Jersey, 636. 

Sandusky, Ohio, 262, 390. — 

Sandy River, 19. 

Saskatchewan River, 13, 199, 220, 244, 259, 
333 et seq., 526, 545. 

Sawkins, J. G., 507. 

Searboro Heights, 584, 585, 587. 

Scandinavia, glaciers of, 104, 106, 445, 447; 
erosion in, 260; maximum post-glacial 
uplift, 506. 

Schenectady, N. Y., 329. 

Schoodic Lake, 350. 

Schoolcraft on the antiquity of man, 699. 

Schuylkill Water-Gap, 197. 

Schwatka, F., explorations in Alaska by, 
29, 30, 190. 

Scioto River, 169, 300, 314, 323, 326, 327, 375, 
561. 

Scoresby explores east coast of Greenland, 
98. 

Scotland, 487, 534; glacial erosion in, 278; 
kames in, 339; glaciation in, 445, 446, 483, 
484; post-glacial erosion in, 568; maxi- 
mum post-glacial uplift, 506. 

Scott, Captain, 120. 

Scratched stones, by moving ice, 125 et seq.; 
by land-slides, 127. 

Scribner, Mr., 701. 

Scudder, Mr. Samuel, on the existence of 
Alpine insects on the White Mountains, 
438, 439. 

Sea cow, 436. 

Sea-level, changes of the, 503. 

Seattle, State of Washington, 21, 135, 180- 
182. 

Second Glacial epoch, 207, 258, 558, 575, 579, 
601, 669. 

Seeman, G. B., visits Kotzebue Sound, 37. 

Selkirk Mountains, glaciers in, 13. 

Serrate character of glacial margin, 132, 
525 et seq. 

Seville, Ohio, 353. 

Seymour, Ind., 601. 

Shackelton, E., 120, 121, 


760 


Shaler, Professor, N. S., 498-500; on depth 
of the drift in New England, 259; on 
drumlins, 288, 290; on glacial action in 
the Connecticut Valley, 486; in Appala- 
chian region, 487; on the Trenton 
gravel, 630. 

Shawshin River, 338. 

Sheep, 436. 

Sheyenne River, 333, 334. 

Shingle Creek, 553, 554. 

-Ship-canal, possible, between Lakes Su- 

perior and Michigan, 306. 

Ship Rock, Mass., 237. 

Siberia, 36, 476, 477, 479. 

Sierra Nevada Mountains, 409, 429, 607, 
611; glaciers in, 13 e¢ seq., 177, 179, 180, 273; 
rock-basins in, 267 et seq.; cirques in, 272 
et seq.;Quaternary uplifts of the, 501, 502, 
507; glaciation of, 568; erosion of, 569. 

Sinclair, Professor W. J., 700. 

Sinian Mountain system, 517. 

Sink-holes, frequent in limestone regions, 
143. 

Sitka, Alaska, 68, 189. 

Skeena River, 25. 

Slickenside, 129. 

Smith Sound, 86, 92, 245. 

Smock, Professor J. C., on depth of ice in 
New Jersey and Pennsylvania, 198. 

Somme River, 574, 623,624. 

Souris River, 334. 

Southall, J. C., 508; on antiquity of man in 
California, 697, 698. 

South America, 437, 478; glaciers of, 104, 108 
et seq., 462; relation of contour of, to the 
Gulf Stream, 472, 473. 

South Bass Island, 262, 266. 

South Brewster, Mass., 139. 

South magnetic pole, 121. 

Spencer, Professor J. W., on the erosive 
power of glaciers, 232, 233; on preglacial 
drainage, 302, 304; on St. Davids, 550. 

Sperry Glacier, 13. 

Spitzbergen, 104, 107, 424, 430, 463. 

Split Rock, Ky., 385, 386. 

Springfield, Ohio, 302. 

Squier, Mr., 385. 

Stainmoor Glacier, 449-451. 

Stark county, Ohio, 169, 326. 

Staten Island, 140. 

St. Davids, Ontario, 537 et seg., 549, 550. 

Steenstrup, K. J. V., onrate of movement ~ 
of Greenland glaciers, 80. 

Stickeen River, 25, 27, 136, 228. 

St. Joseph River, Ohio, 208, 209. 

St. Lawrence River, 305, 314, 354, 357-359, 
398 


INDEX. 


St. Louis, Mo., 134, 171, 315, 591. 

St. Marie’s River, 208, 209. 

Stockbridge, Mass., train of bowlders in, 
239, 240. 

Stone, Professor George H., on moraines in 
Maine, 221; on depth of drift in Maine, 
259; on drumlins in Maine, 286; on kames 
in Schoodic Lake, Me., 350, 351. 

St. Paris, Ohio, 257, 258, 302. 

St. Paul, Minn., 315, 553, 554, 655, 660. 

Strait of Georgia, 186, 188, 192. 

Strait of Juan de Fuca, 182, 192. 

Straits of Magellan, 111. : 

Strie, direction of, on the west coast of 
North America, 183, 186 et seq.; in Maine, 
195; on Hudson Strait, 246; in Western 
Pennsylvania, 248, 249; in Lake Erie, 
265, 266; in Scandinavia, 446; in India, 
484; in Ohio and Indiana, 591; in Illinois, 
591, 592. 

Stroudsburg, Pa., 146, 352, 637. 

Sub-Aftonian till, 224. 

Subglacial streams, source of, 82; of the 
Alps, 18, 255; on Mount Shasta, 18; 
Mount Hood, 19; Mount Tacoma, 21; 
milky-white color of, 18, 21, 135, 136, 254; 
of Muir Glacier, 51, 55, 62, 67, 68, 342; of 
Greenland, 82, 255, 256; transporting 
power of, 67, 68, 82, 135, 136, 254 et seq. 

Submergence during the Glacial epoch in 
North America, 200, 413; in Wales, 453. 

Subsidence in Rocky Mountain region, 

. 200; theory of, to account for lake ridges, 
397, 398; necessary to account for loess 
413; theory of, 413, 416; due to weight of 
ice-sheet, 416, 417, 497, 00, 510, 519; of 
Sahara and central Asia, 433; on the 
Atlantic, north of glacial limit, 635; in 
Vermont, 635; in Dominion of Canada, 
635; general, of the glaciated area, 591; 
in the Delaware Valley, 636-640. 

Sullivan county, Pa., 195. 

Superglacial streams, 22, 48, 75, 90. 

Susquehanna River, 133, 136, 148, 198, 228, 
241, 325, 352. 

Sverdrup, Lieutenant, on east coast of 
Greenland, 98. 

Sweden, 104, 339; chalk bowlder in, 239. 

Switzerland, 463, 496; erosion in, 231, 232, 
274; glaciers of, 445, 448. 


Table Mountain, 692; relics from 694. 
Tacoma, 136. 

Taku Inlet, 27. 

Tapir, 436, 437, 690. 

Tarr, Ralph, 32, 605. 

Taylor, Mr., 543. 


— ee S 
« >» 


INDEX. 761 


Teazes Valley, 309, 379 e¢ seg., 604. 
Temperature, of the southern hemisphere 
lower than that of the northern, 475; of 
the interior of South America, 478; of 
northeast Siberia, 478; not altogether 
dependent on the heat from the sun, 
477; variations of, in different latitudes 
not understood, 479; causes affecting, 480. 
Tennessee, conglomerates in, 487. 
Terminal moraines, 251; conditions favor- 
ing the formation of, 135, 203; char- 
acteristics of, 142; on Nantucket and 
Martha’s Vineyard, 137,203; 0n the Eliza- 
beth Islands, 137, 203; in Plymouth 
county, Mass., 139; in Long Island, 140, 
204; in New Jersey, 142, 151, 206; in east- 
ern Pennsylvania, 144 et seg., 206; on 
Pocono Mountain, 146; in Valley of Fish- 
ing Creek, 148; in valley of Conewango 
Creek, 150; in Ohio, 168 e¢ seg., 207 et seq.; 
in Dakota, 174; in Washington State, 
180; in Wisconsin, 211; south of 
Maine, 195; south of New England, 203; 
in central New York, 206; in Ammonoo- 
suc Valley, 221; in Great Britain, 448 
et seq.; in Germany, 447, 456; compared 
with those of America, 456 et seq.; lobate 
contour of, 132, 207, 528, 530, 661. 
Terraces, glacial, on the Conewango, Ohio, 
150; at Lewiston, Pa., 155; on the Mo- 
hawk, 319; on the St. Croix, 319; on the 
Wabash, 319; on the Mississippi, 315, 
415, 557, 654; on the Ohio and its tribu- 
taries, 323, 370 et seqg.; in western Penn- 
sylvania, 371; on Brush Creek, Ohio, 
372; at Bellevue, Pa., 375, 384; near Mor- 
gantown, W. Va., 377 et seg., 603; at 
Clarksburg and Weston, W. Va., 378; at 
McKeesport, Pa., 379; in Teazes Valley, 
W. Va., 379 et seq., 604; on the Big Sandy, 
W. Va., 382; and Guyandotte, 382; on 
Lake Agassiz, 500, 655, 664; on the Min- 


nesota, 558; on the White, Ind., 601; on | 


Raccoon Creek, Ohio, 603;0n the Somme, 
France, 623, 624; in southern England, 


624, 625; on the Delaware, 633 et seg., on | 


the Little Miami, 645. 


Tertiary era, absence of Glacial epochs | 


during the, 515, 518. 
Thames River, 447, 449. 
Thibet, Quaternary uplift of, 510, 513. 


Thompson, Mr. Gilbert, on the glaciers of 


Mount Shasta, 15. 
Thomson, Sir William, 497. 
Thornville, Ohio, 169. 
Three Sisters, 19. 
Tidioute, Pa., 303. 


| 


Tierra del Fuego, 109, 110. 

Tight, Professor, on Kanawha drainage, 
309; on Middle Ohio drainage, 309. 

Till, defined, 123, 129 et seqg.; depth of, 257, 
et seq.; British Columbia, 185; in Minne- 
sota, 213, 258, 555, 695, 607; in Canada, 
258; in Indiana, 257, 60i,602;in Illinois., 
257; in Ohio, 257, 258, 592, 593, 599, 600; 
in New England, 259; in Pennsylvania, 
259, 260, 604; in Europe, 260; average in 
North America, 280. 

Tioga county, Pa., 195. 

Titusville, Pa., 326. 

Todd, Professor J. E., on glacial dams 
across the Kansas and Platte River, 
172; on Coteau des Prairies, 214; Missouri 
coteau, 215, 217; on glacial drainage, 332. 

Tonawanda Creek, 542. 

Topeka, Kan., 172. 

Toronto, Can., 584, 585, 586. 

Torsukatak Glacier, 78. 

Towson, Mr., 117, 118. 

Trade-winds, motions of, in the Atlantic, 
470; relations to the Gulf Stream, 472; 
cause of the predominance of the south- 
east, 473 et seq. 

Transportation by subglacial streams, 135, 
136, 254 et seqg.; in Alaska, 67, 68, 136; in 
Greenland, 82, 256; in the Alps, 254, 255. 

Transportation of bowlders, 236 e¢ seg.; in 
Alaska, 45; direction of, 196, 240 et seq.; 
in Europe, 236; in New England, 237 
et seqg.; in New Jersey, 241; in Pennsyl- 
vania, 241; in Ohio, 242; in Indiana and 
Illinois, 243; beyond the Missouri River, 
243 et seq.; in British America, 176, 244 
et seg.; on northeastern Mackenzie River, 
245; upward, 246 e¢ seg.; in Scotland, 484; 
in Africa, 485; in India, 485. 

Transportation of till, 257 et seg.; in Ohio, 
257; in the Red River region, 258; in New 
England, 259; in Pennsylvania, 259; in 
Europe, 260. 

Transporting power of rivers, 638. 

Trenton, N. J., 329; paleolithie imple- 
ments at, 541, 619, 620, 625 et seq., 645, 
671. 

Trenton gravel, 631-633, 637 et seq., 671. 

Tschernyschey, Professor, 586. 

Tuckernuck Island, 137. 

Tundra in Alaska, 36, 37. 

Tuolumne county, Cal., 13, 180, 689 et seq. 

Tuscarawas River, Ohio, 301, 316, 326. 

Two glacial epochs, 575 et seg., 607 et seq., 
669. 

Tyndall, Professor John, measurements 
of glaciers, 2, 3, 41, 81. 


762 
Tyndall Glacier, 87. 
Tyrol Mountains, 104, 365. 


Uintah Mountains, 178, 179. 

Unalaska, island of, 36. 

Uniformitarianism, 532, 533. 

Upham, Mr. Warren, 497, 504; discovers 
terminal moraine, 134; traced moraine 
through Iowa and eastern Dakota, 211, 
212; on depth of drift, 258, 259; on drum- 
lins, 282, 283, 287, 289, 292; on Brown’s 
Valley, 316; on glacial drainage in the 
Northwest, 330 et seqg.; in British 
America, 335; on kames in the Con- 
necticut Valley, 345; on the gravel 
plains north of Portland, Me., 349; 
on kame-like ridges in Minnesota, 353; 
on lakes of Minnesota, 361, 362; on 
Lake Agassiz, 401-406, 548, 548; on 
loess, 415, 416; on Lewis’s work in 
England, 448, 452; on shells near Bos- 
ton, Mass., 453; on probable causes of 
glaciation, 497; on vegetable deposits in 

.. northern Minnesota, 607; on paleolithic 
implements, 654 et seq. 

Ural Mountains, 108, 447. 

Utah, former glaciers in, 176, 177. 


Vancouver on glaciers of Alaska, 22 et seq., 
30; visit to Disenchantment Bay, 31; on 
Glacier Bay, 59 et seq. 
Vancouver Island, 183, 185 et seq., 192, 505. 
Vegetable remains in glacial deposits, near 
Muir Glacier, 61 et seq., 233, 592; at Point 
Wilson, 182, 183; at Morgantown, W. Va., 
377, 378, 384, 603; in Teazes Valley, 381, 
604; theory of, 576, 579; in Montgomery 
county, Ohio, 592, 593; in Butler county, 
Ohio, 592, 598 et seq.; in Morgan, Jackson, 
Jennings, and Jefferson counties, Ind., 
601, 602; in Hamilton, Highland, Ross, 
and Licking counties, Ohio, 602, 603; in 
southwestern Indiana, 603; in Penn- 
sylvania, 604; in Minnesota, 605 
Vegetation in the vicinity of Muir Glacier, 
41, 69. 
Veins in glacial ice, 7. 
Vermont, 194, 247, 635, 665. 
Vessel Rock, N. H., 236. 
Victoria, glacial grooves near, 183, 184. 
Victoria Glacier, 13. 
Viscosity of ice, 88, 96. 
Volcanic outflows probably correlated with 
glaciation, 501. 
Volcanoes indicating molten interior of the 
earth, 499. 
Volk, Mr. Ernest, 630. 


INDEX. 


Waagen, Dr. W., 516. 
Wabash River, 170, 300, 314, 323, 326, 353, 
354. 


Wadsworth, Professor M: E., 498. 


Wahsatch Mountains, 149-179, 274, 336. 

Wakefield, N. H., 351. : 

Wales, 446, 450, 453, 484. * 

Wallace, A. R., 436, 508, 514, 516-518. 

Wallenpaupack Creek, Pa., 311. 

Walrus, 436, 438, 641, 675. 

Warner, L. C., 306. 

Warping rafts, 351. 

Warren county, Pa., terminal moraine in, 
149, 150; preglacial drainage in, 307. 

Warren, Pa., 149, 150,307; kettle-hole in, 
598. ‘ 

Washington county, Pa., 604. 

Washington Land, 86, 92, 94, 97. 

Washington, State of, 135, 178, 180, 181; 
glaciers in, 19 et seq., 177, 191, 222. 

Watch Hill, 140. 

Water, peculiarities of its freezing-point, 
1, 4, 5. 
Waterfalls, scarcity of, in unglaciated re- 

gions, 362. 

Watertown, N. Y., 481. 

Wells in Ohio, 168, 169, 257, 258, 602; in 
British Columbia, 185; in Pennsylvania, 
260, 604; in Indiana, 300, 601, 602; near 
Morgantown, W. Va., 377; in Minnesota, 
555, 605, 607. 

Wells, Mr. David A., 238. 

Wenkchemna Glavter, 13. 

Wensleydale Glacier, 449, 450. 

Weston, W. Va., 378. 

West Virginia, 604; terraces in, 377 et seq., 
603, 604; vegetable remains in glacial 
deposits in, 377 et seq., 603, 604; wells in, 
377; transported bowlders in, 379, 382. 

Whirlpool in Niagara River, 536 et seq., 
549 et seq., 551. 

White Glacier, 72. 

White Mountains, Alaska, 43, 61. 

White Mountains, N. H., 429, 438 et segq., 
519. 

White, Professor I. C., 605; on the Cin- 
cinnati ice-dam, 197, 370, 371, 384, 603; 
reports wells in Wyoming county, ‘Pa., 
260; reports buried channels in Pike and 
Monroe counties, Pa., 311; on terraces in 
West Virginia, 377 et seq., 382, 384; on the 
Monongahela ice-dam, 391-393. 

Whittlesey, Colonel Charles, 500; on forma- 
tion of kettle-holes, 144; reports wells in 
Ohio, 602. 

White River, Dak., 173. 

White River, Ind., 601, 649. 


INDEX. 


White River, Ore., 19. 

White River, State of Washington, 21-23. 

Whitney, Professor J. D., 498, 513; ascent 
of Mount Shasta by, 18; cited, 108, 176, 
178; on glaciers of New Zealand, 112; on 
formation of Yosemite Valley, 180, 271; 
on cause of ice age, 464; paleolithic dis- 
coveries of, 627; on antiquity of man in 
California, 688, 692 et seq.; on deep 
placers of California, 689, 690. 

Whymper on Greenland glaciers, 82 et seq.; 
cited, 108. 

Williams, Professor E. H., 582, 584; on the 
attenuated border, 151-166. 

Williamson county, IIl., 170, 171. 

Willoughby Island, 44, 61, 189. 

Wilson, Mr. Thomas, 623. 

Winchell, Professor A., 5; on the effect 
of pressure of a glacier, 417, 418; on antiq- 
uity of man in California, 698. 

Winchell, Professor N. H., 508, 517, 597; 
on rate of recession of Falls of St. An- 
thony, 552 et seq., 665; paleolithie dis- 
coveries of, 537, 656, 660. 


763 


Wind River Mountains, 13. 

Wind, transporting power of, 408, 409. 

Winooski River, 347. 

Winslow, Dr. C. F., 692. 

Wisconsin, 525; driftless area of, 134, 413, 
414, 527; depth of ice in, 201; kettle-range 
in, 134, 144, 210 et seq., 221, 361; drift hills 
in, 286; lakes in, 361; loess in, 413, 414; 
post-glacial erosion in, 568. 

Wisconsin episode, 222 e¢ seq. 

Woeikoff, on Croll’s theory of the cause of 
the Glacial period, 474; on glaciers of the 
southern hemisphere, 475, 476; on dis- 
tribution of heat over the earth, 478, 479 
et seq. 

Wood Glacier, 74. 

Wood’s Holl, 137, 139, 204, 205. 

Woodward, Mr. R. S., 295, 503; on rate of 
recession of Niagara Falls, 540. 

Wright, C. W., 72. 

Wright, F. E., 72. 

Wright, Professor G. F., 508, 517, 665. 

Wright, Professor W. E. C., 349. 

Wyman, Dr., 693.