7/5f *• * m^ '•4/ ^■a 0m • f ^f/'.* CORNELL UNIVERSITY LIBRARY FROM C.V.P.YoTang QE 697.W9Tl90r"''''-'''"'^ Man and the glacial period. 3 1924 004 619 361 Cornell University Library The original of tliis book is in tine Cornell University Library. There are no known copyright restrictions in the United States on the use of the text. http://www.archive.org/details/cu31924004619361 I JR AND GLACIAL MAP SCA "^ OF M L^'g ^0 00 ELEVATIONS [ H rrom Sea Lt-vel to aSOFctt f,^ 2o0 to (Xl Feet ^^ n to ^ OtO Ptet EB Vljo\e ((OF et il M M M »■ Track f LakoDl'^ rictli than Shap Oranitc _ _Trafkof ViltJi Orai„ Gramt _ Track of Galloway Granite; ^ ^ liap Granite _„_„_,,_T"a<_kcC"\\ clbhPock;, Intlioate the BounJarits f trtams or thu i usition II(.ramc3 STRPTHERS A CO. N. Longitude MAN AND THE GLACIAL PERIOD BY G. FREDERICK WRIGHT D. D., LL. D., F. G. S. A. PROFESSOR IN OBERLIN THEOLOGICAL SEMINARY, FORMERLY ASSISTANT ON THE UNITED STATES GEOLOGICAL SURVEY, AUTHOR OF THE ICE AGE IN NORTH AMERICA, LOGIC OF CHRISTIAN EVIDENCES, ETC. IVITH AN APPENDIX ON TERTIARY MAN BY PROF. HENRY W. HAYNES FULLY ILLUSTRATED NEW YORK APPLETON AND COMPANY 1904 Copyright, 1892, By D. APPLETON AND COMPANY. Electrotyped and Printed AT THE APPLiETON PrESS, U. S. A. TO JUDGE C. C. BALDWIN PKESIDENT OF THE WESTERI* KESEKVE HISTORICAL SOCIETY CLEVELAND THIS VOLUME IS DEDICATED IN RECOONITION OF HIS SAGACIOUS AND UNPAILtNG INTEREST IN THE INVESTIGATIONS WHICH HAVE MADE IT POSSIBLE PEEFAOE TO THE SECOND EDITION. Since, as stated in the Introduction (page 1), the plan of this volume permitted only " a concise presenta- tion of the facts," it was impossible to introduce either full references to the illimitable literature of the subject or detailed discussion of all disputed points. The facts selected, therefore, were for the most part those upon which it was supposed there would be pretty general agreement. The discussion upon the subject of the continuity of the Glacial period was, however, somewhat elaborate (see pages 106-121, 311, 334, 333), and was presented with excessive respect for the authority of those who maintain the opposite view ; all that was claimed (page 110) being that one might maintain the unity or continuity of the Glacial period " without forfeiting his right to the respect of his fellow-geologists." But it already appears that there was no need of this extreme modesty of statement. On the contrary, the vigorous discussion of the subject which has characterized the last two years reveals a de- cided reaction against the theory that there has been more than one Glacial epoch in Quaternary times ; while there have been brought to light many most important if not conclusive facts in favour of the theory supported in the volume. In America the continuity of the Glacial period has been, maintained during the past two years with impor- viii MAN AND THE GLACIAL PERIOD. tant new evidence, among others by authorities of no less eminence and special experience in glacial investigations than Professor Dana,* Mr. Warren Upham,f and Profess- or Edward H. Williams, Jr.J Professor Williams's inves- tigations on the attenuated border of the glacial deposits in the Lehigh, the most important upper tributary to the Delaware Valley, Pa., are of important significance, since the area which he so carefully studied lies wholly south of the terminal moraine of Lewis and Wright, and belongs to the portion of the older drift which Professors Cham- berlin and Salisbury have been most positive in assign- ing to the first Glacial epoch, which they have main- tained was separated from the second epoch by a length of time sufficient for the streams to erode rock gorges in the Delaware and Lehigh Kivers from two hundred to thi-ee hundred feet in depth.* But Professor Williams has found that the rook gorges of the Lehigh, and even of its southern tributaries, had been worn down approximately to the present depth of that of the Delaware before this earliest period of glaciation, and that the gorges were filled with the earliest glacial debris. A similar relation of the glacial -deposits of the atten- uated border to the preglacial erosion of the rock gorges of the Alleghany and upper Ohio Eivers has been brought to light by the joint investigations of Mr. Prank Leverett and myself in western Pennsylvania, in the vicinity of * American Journal of Science, vol. xlvi, pp. 327, 330. t American Journal of Science, vols, xlvi, pp. 114^131 ; xlvii, pp. 358-865 ; American Geologist, vols, x, pp. 839-863, especially pp. 361, 862; xiii, pp. 114, 378; Bulletin of the Geological Society of America, vol. v, pp. 71-86, 87-100. X Bulletin of the Geological Society of America, vol. v, pp. 13-16, 281-396 ; American Journal of Science, vol. xlvii, pp. 83-36. * See especially Chamberlin, in the American Journal of Sci- ence, vol. xlv, p. 193 ; Salisbury, in the American Geologist, vol. xi, p. 18, PKEPACE TO THE SECOND EDITION. IX Warren, Pa., where, in an area which was affected by only the earliest glaciation, glacial deposits are found tilling the rock channels of old tributaries to the Alleghany to a depth of from one hundred and seventy to two hundred and fifty feet, and carrying the preglacial erosion at that point very closely, if not quite, down to the present rock bottoms of all the streams. This removes from Professor Chamberlin a most important part of the evidence of a long interglacial period to which he had appealed ; he having maintained * that " the higher glacial gravels antedated those of the moraine-forming epoch by the measure of the erosion of the channel through the old drift and the rock, whose mean depth here is about three hundred feet, of which perhaps two hundred and fifty feet may be said to be be rock," adding that the " exca- vation that intervened between the two epochs in other portions of the Alleghany, Monongahela, and upper Ohio valleys is closely comparable with this." These observations of Mr. Leverett and myself seem bo demonstrate the position maintained in the volume (page 218), namely, that the inner precipitous rock gorges of the upper Ohio and its tributaries are mainly preglacial, rather than intergla,cia.\. The only way in which Professor Chamberlin can in any degree break the force of this discovery is by assuming that in preglacial times the present narrow rock gorges of the Alleghany and the Ohio were not continuous, but that (as indicated in the present volume on page 206) the drainage of various portions of that region was by northern outlets to the Lake Erie basin, leaving, on this supposition, the cols between two or three drainage areas to be lowered in gla- cial or interglacial time. On the theory of continuity the erosion of these cols 'Bulletin 58 of the United States Geological Survey, p. 35; American Journal of Science, vol. xlv, p. 195. X MAN AND THE GLACIAL PERIOO. would have been rapidly effected by the reversed drainage consequent upon the arrival of the ice-front at the southern shore of the Lake Erie basin. During all the time elapsing thereafter, until the ice had reached its southern limit, the stream was also augmented by the annual partial melting of the advancing glacier which was constantly bringing into the valley the frozen precipitation of the far north. The distance is from thirty to seventy miles, so that a moderately slow advance of the ice at that stage would afEord time for a great amount of erosion before suflBcient northern gravel had reached the region to begin the filling of the gorge.* Mr. Leverett also presented an important paper before the Geological Society of America at its meeting at Madi- son, Wis., in August, 1893, adducing evidence which, he thinks, goes to prove that the postglacial erosion in the earlier drift in the region of Eock Eiver, 111., was seven or eight times as much as that in the later drift farther north ; while Mr. Oscar H. Hershey arrives at nearly the same conclusions from a study of the buried channels in northwestern Illinois, f But even if these estimates are approximately correct — which is by no means certain — they only prove the length of the Glacial period, and not necessarily its discontinuity. At the same time it should be said that these investi- gations in western Pennsylvania somewhat modify a por- tion of the discussion in the present volume concerning the effects of the Cincinnati ice-dam. It now appears that the full extent of the gravel terraces of glacial origin in * See an elaborate discussion of the subject in its new phases by Chamberlin and Leverett, in the American Journal of Science, vol- xlvii, pp. 247-283. f American Greologist, vol. xii, p. 314f. Other important evi- dence to a similar effect is given by Mr. Leverett, in an article on The Glacial Succession in Ohio, Journal of Geology, vol. i, pp. 129- 146. PKBPACE TO THE SECOND EDITION. xi the Afleghany Eiver had not before been fully appreciated, since they are nearly continuous on the two-hundred-foot rock shelf, and are often as much as eighty feet thick. It seems probable, therefore, that the Alleghany and upper Ohio gorge was filled with glacial gravel to a depth of about two hundred and fifty or three hundred feet, as far down at least as Wheeling, W. Va. If this was the case, it would obviate the necessity of bringing in the Cincinnati ice-dam (as set forth in pages 213-316) to account direct- ly for all the phenomena in that region, except as this ob- struction at Cincinnati would greatly facilitate the silting up of the gorge. The simple accumulation of glacial gravel in the Alleghany gorge would of itself dam up the Monongahela at Pittsburg, so as to produce the results detailed by Professor White on page 315.* Of European authorities who have recently favoured the theory of the continuity of the Quaternary Glacial period, as maintained in the volume, it is enough to mention the names of Prestwich, f Hughes, J Kendall,* Lamplugh, || and Wallace,'*' of England ; Falsan, of France ; Hoist, J of Sweden ; Credner J and Diener, J of Germany ; and * For a fuU discussion of these topics, see paper by Professor B. C. Jillson, Transactions of tlie Academy of Science and Art of Pittsburg, December 8, 1893 ; G. F. Wright, American Journal of Science, vol. xlvii, pp. 161-187 ; especially pp. 177, 178 ; The Popu. lar Science Monthly, vol. xlv, pp. 184-198. f Quarterly Journal of the Geological Society for August, 1887. ^ American Geologist, vol. viii, p. 341. * Transactions of the Leeds Geological Association for February 16, 1893. II Quarterly Journal of the Geological Society, August, 1891. ^ Fortnightly Review, November, 1893, p. 633 ; reprinted in The Popular Science Monthly, vol. xliv, p. 790. <) La Periode glaciaire (Felix Alcan, Paris, 1889). i American Geologist, vol. viii, p. 242. $Ibid., p. 241: I Ibid., p. 343. xii MAN AND THE GLACIAL PERIOD, Nikitin * and Kropotkin, f of Eussia. J Among leading authorities still favouring a succession of Glacial epochs are : Professor James Geikie, * of Scotland ; Baron de Geer, II of Sweden; and Professor Felix Wahnschaffe,'*- of Germany. When the first edition was issued, two years ago, there seemed to be a general acceptance of all the facts detailed in it which directly connected man with the Glacial period both in America and in Europe ; and, indeed, I had stu- diously limited myself to such facts as had been so long and so fully before the public that there would seem to be no necessity for going again into the details of evidence relating to them. It appears, however, that this confi- dence was ill-founded ; for the publication of the book seems to have been the signal for a confident challenge, by Mr. W. H. Holmes, of all the American evidence, with intimations that the European also was very likely equally defective. In particular Mr. Holmes denies the conclu- siveness of the evidence of glacial man adduced by Dr. Abbott and others at Trenton, N. J. ; Dr. Metz, at Madi- sonville, Ohio ; Mr. Mills, at Newcomerstown, Ohio ; and Miss Babbitt, at Little Falls, Minn. The sum of Mr. Holmes's effort amounts, however, to * CongrSs International d'Archeologie, Moscow, 1893. \ Nineteenth Century, January, 1894, p. 151, note. X The volume The Glacial Geology of Great Britain and Ireland, edited from the unpublished MSS. of the late Henry Carvill Lewis (London, Longmans, Green & Co., 1894), adds much important evi- 'dence in favour of the continuity of the Glacial epoch ; see especially pp. 187, 460, 461, 466. * Transactions of the Royal Society of Bdinbuifgh, vol. xxxvii, Part I, pp. 137-150. II American Geologist, vol. viii, p. 346. ^ Porsohungen zur deutschen Landes und Volkskunde von Dr. A. KirchhofE. Bd. vi. Heft i. Journal of Geology, vol. i, pp. 15-37, 147-163 ; American Ge- ologist, vol. xi, pp. 319-340. PREFACE TO THE SECOND EDITION. xiii little more than the statement that, with a limited amount of time and labour, neither he nor his assistants had been able to find any implements in undisturbed gravel in any of these places; and the suggestion of various ways in which he thinks it possible that the observers mentioned may have been deceived as to the original position of the implements found. But, as had been amply and repeat- edly published,* Professor J. D. Whitney, Professor Lucien Carr, Professor N. S. Shaler, Professor P. W. Putnam, of Harvard University, besides Dr. C. 0. Abbott, all expressly and with minute detail describe finding implements in the undisturbed gravel at Trenton, which no one denies to be of glacial origin. In the face of such testimony, which had been before the public and freely discussed for several years, it is an arduous undertaking for Mr. Holmes to claim that none of the implements have been found in place, because he and his assistants (whose opportunities for observation had scarcely been one twentieth part as great as those of the others) failed to find any. To see how care- fully the original observations were made, one has but to read the reports to Professor Putnam which have from time to time appeared in the Proceedings of the Peabody Museum and of the Boston Society of Natural History, and which are partially summed up in the thirty-second chapter of Dr. Abbott's volume on Primitive Industry. In the case of the discovery at Newcomerstown, Mr. Holmes is peculiarly unfortunate in his efforts to present the facts, since, in endeavouring to represent the conditions under which the implement was found by Mr. Mills, he has relied upon an imaginary drawing of his own, in which an utterly impossible state of things is pictured. The claim of Mr. Holmes in this case, as in the other, is that * Proceedings of the Boston Society of Natural History, vol. xxi, January 19, 1881 ; Report of the Peabody Museum, vol. ii, pp. 44- 47 ; chap, xxxii of AbTsott's Primitiye Industry ; American Geolo- gist, vol. xi, pp. 180-184. 1 xiv MAN AND THE GLACIAL PERIOD. possibly the gravel in which the implements were found had been disturbed. In some cases, as in Little Falls and at Madison ville, he thinks the implements may have worked down to a depth of several feet by the overturning of trees or by the decay of the tap-root of trees. A suffi- cient answer to these suggestions is, that Mr. Holmes is able to find no instance in which the overturning of trees has disturbed the soil to a depth of more than three or four feet, while some of the implements in these places had been found buried from eight to sixteen feet. Even if, as Mr. Chamberlin suggests,* fifty generations of trees have decayed on the spot since the retreat of the ice, it is difficult to see how that would help the matter, since the effect could not be cumulative, and fifty upturnings of three or four feet would not produce the results of one up- turning of eight feet. Moreover, at Trenton, where the upturning of trees and the decaying of tap-roots would have been as likely as anywhere to bury implements, none of those of flint or jasper (which occur upon the sur- face by tens of thousands) are buried more than a foot in depth ; while the argillite implements occur as low down as fifteen or twenty feet. This limitation of flint and jas- per implements to the surface is conclusively shown not only by Dr. Abbott's discoveries, but also by the extensive excavations at Trenton of Mr. Ernest Volk, whose collec- tions formed so prominent a part of Professor Putnam's Palaeolithic exhibit at the Columbian Exposition at Chi- cago. In the village sites explored by Mr. Volk, argillite was the exclusive material of the implements found in the lower strata of gravel. Similar results are indicated by the excavations of Mr. H. C. Mercer at Point Pleasant, Pa., about twenty miles above Trenton, where, in the lower strata, the argillite specimens are sixty-one times more numerous than the jasper are. * American Geologist, vol. xi, p. 188. PREFACE TO THE SECOND EDITION. xv To discredit the discoveries at Trenton and New- comerstown, Mr. Holmes relies largely upon the theory that portions of gravel from the surface had slid down to the bottom of the terrace, carrying implements with them, and forming a talus, which, he thinks, Mr. Mills, Dr. Ab- bott, and the others have mistaken for undisturbed strata of gravel. In his drawings Mr. Holmes has even repre- sented the gravel at Newcomerstown as caving down into a talus without disturbing the strata to any great extent, and at the same time he speaks slightingly of the promise which I had made to publish a photograph of the bank as it really was. In answer, it is sufficient to give, first, the drawing made at the time by Mr. Mills, to show the gen- eral situation of the gravel bank at Newcomerstown, in which the implement figured on page 253 was found ; and, secondly, an engraving from a photograph of the bank, taken by Mr. Mills after the discovery of the implement, but before the talus had obscured its face. The imple- ment was found by Mr. Mills with its point projecting from a ftesh exposure of the terrace, just after a mass, loosened by his own efforts, had fallen away. The gravel is of such consistency that every sign of stratification disap- pears when it falls down, and there could be no occasion for a mistake even by an ordinary observer, while Mr. Mills was a well-trained geologist and collector, making his notes upon the spot.* I had thought at first that Mr. Holmes had made out a better case against the late Miss Babbitt's discoveries at Little Falls (referred to on page 254), but in the American Geologist for May, 1894, page 363, Mr. Warren Upham, after going over the evidence, expresses it as still his con- viction that Mr. Holmes's criticism fails to shake the force of the original evidence, so that I do not see any reason for modifying any of the statements made in the body of the * The Popular Science Monthly, vol. xliii, pp. 39-39. XVI MAN AND THE GLACIAL PERIOD. book concerning the implements supposed to have been found in glacial deposits. Yet if I had expected such an avalanche of criticism of the evidence as has been loosened, I should at the time have fortified my statements by fuller ^ references, and should possibly have somewhat enlarged the discussion. But this seemed then the less necessary, from the fact that Mr. McGee had, in most emphatic manner, indorsed nearly every item of the evidence ad- PRBPACB TO THE SECOND EDITION. XVll duced by me, and much more, in an article which appeared in The Popular Science Monthly four years before the pub- lication of the volume (November, 1888). In this article he had said : " But it is in the aqueo-glacial gravels of the Delaware Eiver at Trenton, which were laid down contemporane- xviii MAN AND THE GLACIAL PERIOD. ously with the terminal moraine one hundred miles farther northward, and which have been so thoroughly studied by Abbott, that the most conclusive proof of the existence of glacial man is found" (p. 23). "Excluding all doubtful cases, there remains a fairly consistent body of testimony indicating the existence of a widely distributed human population upon the North American continent during the later Ice epoch" (p. 24). "However the doubtful cases may be neglected, the testimony is cumulative, parts of it are unimpeachable, and the proof .of the existence of glacial man seems conclusive " (p. 25). In view of the grossly erroneous statements made by Mr. McGee concerning the Nampa image (described on pages 298, 299), it is necessary for me to speak somewhat more fully of this important discovery. The details concern- ing the evidence were drawn out by me at length in two communications to the Boston Society of Natural History (referred to on page 297), which fill more than thirty pages of closely printed matter, while two or three years before the appearance of the volume the facts had been widely published in the New York Independent, the Scientific American, The Nation, Scribner's Magazine, and the At- lantic Monthly, and in Washington at a meeting of the Geological Society of America in 1890. In the second communication to the Boston Society of Natural History an account was given of a personal visit to the Snake Eiver Valley, largely for the purpose of further investigation of the evidence brought to my notice by Mr. Charles Francis Adams, and of the conditions under which the figurine was found. Among the most important results of this in- vestigation was the discovery of numerous shells under the lava deposits, which Mr. Dall, of the United States Geo- logical Survey, identified for me as either post-Tertiary or late Pliocene ; thus throwing the superficial lava deposits of the region into the Quaternary period, and removing from the evidence the antecedent improbability which would PREFACE TO THE SECOND EDITION. xix bear so heavily against it if we were compelled to suppose that the lava of the Snake Kiver region was all of Tertiary or even of early Quaternary age. Furthermore, the evi- dence of the occurrence of a great debdcle in the Snake Kiver Valley during the Glacial period, incident upon the bursting of the banks of Lake Bonneville, goes far to re- move antecedent presumptions against the occurrence of human implements in such conditions as those existing at Nampa (see below, pp. 233-237). Mr. McGee's misunderstanding of the evidence on one point is so gross, that I must make special reference to it. He says * that this image " is alleged to have been pounded out of volcanic tuff by a heavy drill, . . . under a thick Tertiary lava bed." The statement of facts on page 298 bears no resemblance to this representation. It is there stated that there were but fifteen feet of lava, and that near the surface ; that below this there was nothing but alternating beds of clay and quicksand, and that the lava is post-Tertiary. The sand-pump I should perhaps have described more fully in the book, as I had already done in the communication to the Boston Society of Natural His- tory. It was a tube eight feet long, with a valve at the bottom three and a half inches in diameter on the inside. Through this it was the easiest thing in the world for the object, which is only one inch and a half long, to be brought up in the quicksand without injury. The baseless assertions of Mr. McGee, involving the honesty of Messrs. Kurtz and Duffes, are even less fortu- nate and far more reprehensible. " It is a fact," says Mr. McGee, " that one of the best-known geologists of the world chanced to visit Nampa while the boring was in progress, and the figurine and the pretty fiction were laid before him. He recognized the figurine as a toy such as the neighbouring Indians give their children, and laughed * Literary Northwest, vol. ii, p. 275. XX MAN AND THE GLACIAL PERIOD. at the story ; whereupon the owner of the object enjoined secrecy, pleading : ' Don't give me away ; I've fooled a lot of fellows already, and I'd like to fool some more.' " * This well-known geologist, on being challenged by Profess- or Claypole f to give " a full, exact, and certified statement of the conversation " above referred to, proved to be Major Powell, who responded with the following statement : " In the fall of 1889 the writer visited Boise City, in Idaho [twenty miles from Nampa]. While stopping at a hotel, some gentlemen called on him to show him a figurine which they said they had found in sinking an artesian well in the neighbourhood, at a depth, if I remember rightly, of more than three hundred feet. . . . When this story was told the writer, he simply jested with those who claimed to have found it. He had known the Indians that live in the neighbourhood, had seen their children play with just such figurines, and had no doubt that the little image had lately belonged to some Indian child, and said the same. While stopping at the hotel different persons spoke about it, and it was always passed ofE as a jest ; and various comments were made about it by various people, some of them claiming that it had given them much sport, and that a good many tenderfeet had looked at it, and believed it to be genuine; and they seemed rather pleased that I had detected the hoax." I Thus it appears that Major Powell has made no such statement, at least in public, as Mr. McGee attributes to him. It should be said, also, that Major Powell's memory is very much at fault when he affirms that there is a close resemblance between this figurine and some of the chil- dren's playthings among the Pocatello Indians. On the * American Anthropologist, vol. vi, p. 94 ; repeated by Mr. Mc- Gee in the Literary Northwest, vol. ii, p. 276. f The Popular Science Monthly, vol. xlii, p. 773, i Ibid., vol. xliii, pp. 322, 333. PREFACE TO THE SECOND EDITION. xxi contrary, it would have been even more of a surprise to find it in the hands of these children than to find it among the prehistoric deposits on the Pacific coast. To most well-informed people it is sufficient to know that no less high authorities than Mr. Charles Francis Adams and Mr. Gr. M. Gumming, General Manager for the Union Pacific line for that district, carefully inves- tigated the evidence at the time of the discovery, and, knowing the parties, were entirely satisfied with its sufii- ciency. It was also subjected to careful examination by Professor F. W. Putnam, who discerned, in a deposit of an oxide of iron on various parts of the image, indubitable evidence that it was a relic which had lain for a long time in some such condition as was assigned to it in the bottom of the well — all of which is detailed in the papers re- ferred to below, on page 397. Finally, the discovery, both in its character and con- ditions, is in so many respects analogous to those made under Table Mountain, near Sonora, Cal. (described on pages 394-297), that the evidence of one locality adds cumulative force to that of the other. The strata under- neath the lava in which these objects were found are all indirectly, but pretty certainly, connected with the Glacial period.* No student of glacial archaeology, therefore, can hereafter afford to disregard these facts from the Pacific coast. Obbrlin, Ohio, JvMe 2, 1894. * See below, p. 349. PREFACE TO THE FIRST EDITION. The wide interest manifested in my treatise upon The Ice Age in North America and its Bearing upon the An- tiquity of Man (of which a third edition was issued a year ago), seemed to indicate the desirability of providing for the public a smaller volume discussing the broader ques- tion of man's entire relation to the Glacial period in Eu- rope as well as in America. When the demand for such a volume became evident, I set about preparing for the task by spending, first, a season in special study of the lava-beds of the Pacific coast, whose relations to the Gla- cial period and to man's antiquity are of such great in- terest ; and, secondly, a summer in Europe, to enable me to compare the facts bearing upon the subject on both continents. Of course, the chapters of the present volume relating to America cover much of the same ground gone over in the previous treatise ; but the matter has been entirely re- written and very much condensed, so as to give due pro- portions to all parts of the subject. It will interest some to know that most of the new material in this volume was first wrought over in my second course of Lowell Institute Lectures, given in Boston during the month of March last. I am under great obligations to Mr. Charles Francis Adams for his aid in prosecuting investigations upon the Pacific coast of America ; and also to Dr. H. W. Crosskey, xxiv MAN AND THE GLACIAL PEEIOD. of Birmingham, England, and to Mr. Q. W. Lamplugh, of Bridlington, as well as to Mr. C. B. De Kance and Mr. Clement Reid, of the British Geological Survey, besides many others in England who have facilitated my investi- gations ; but pre-eminently to Prof. Percy F. Kendall, of Stockport, who consented to prepare for me the portion of Chapter VI which relates to the glacial phenomena of the British Isles. I have no doubt of the general cor- rectness of the views maintained by him, and little doubt, also, that his clear and forcible presentation of the facts will bring about what is scarcely less than a revolution in the views generally prevalent relating to the subject of which he treats. For the glacial facts relating to France and Switzer- land I am indebted largely to M. Falsan's valuable com- pendium. La Periode Glaciaire. It goes without saying, also, that I am under the deep- est obligation to the works of Prof. James Geikie upon The Great Ice Age and upon Prehistoric Europe, and to the remarkable volume of the late Mr. James Croll upon Climate and Time, as well as to the recent comprehen- sive geological treatises of Sir Archibald Geikie and Prof. Prestwich. Finally, I would express my gratitude for the great courtesy of Prof. Fraipont, of Liege, in assisting me to an appreciation of the facts relating to the late remark- able discovery of two entire skeletons of Palaeolithic man in the grotto of Spy. Comparative completeness is also given to the volume by the appendix on the question of man's existence during the Tertiary period, prepared by the competent hand of Prof. Henry W. Haynes, of Boston. I trust this brief treatise will be useful not only in interesting the general public, but in giving a clear' view of the present state of progress in one department of the inquiries concerning man's antiquity. If the conclusions reached are not as positive as could be wished, still it is PREFACE TO THE FIRST EDITION. xxv both desirable and important to see what degree of indefl- niteness rests upon the subject, in order that rash specu- lations may be avoided and future investigations directed in profitable lines. G. Feedeeick Weight. Obeblin, Ohio, May 1, 1892. CONTENTS. CHAPTER I. PAGES Introduotobt . 1-8 CHAPTER 11. Existing Glaciers 9-43 In Europe ; in Asia ; in Oceanica ; in South America ; on the Antarctic Continent ; in North America. CHAPTER III. Glacial Motion 43-50 CHAPTER IV. Signs op Past Glaciation 51-65 CHAPTER V. Ancient Glaciers in the Western Hemisphere . . 66-128 New England; New York, New Jersey, and Pennsyl- vania ; the Mississippi Basin ; west of the Rooky Mountains. CHAPTER VI. ' Ancient Glaciers in the Eastern Hemisphere . . 129-193 Central and Southern Europe; the British Isles — the Preglacial Level of the Land, the Great Glacial Cen- tres, the Confluent Glaciers, the East Anglian Glacier, the so-called Great Submergence ; Northern Europe ; Asia ; Africa. xxviii MAN A^TD THE GLACIAL PERIOD. CHAPTER VII. PAGES Drainage Systems in the Glacial Period . . . 193-241 In America — Preglacial Erosion, Burled Outlets and Channels, loe-dams. Ancient Riyer Terraces ; in Europe. CHAPTER VIII. Relics op Man in the Glacial Period .... 243-301 In Glacial Terraces of the United States ; in Glacial Terraces of Europe; in Cave Deposits in the British Isles ; in Cave Deposits on the Continent ; Extinct Animals associated with Man; Earliest Man on the Pacific Coast of North America. CHAPTER IX. The Cause of the Glacial Period 302-381 CHAPTER X. The Date of the Glacial Period 332-864 Appendix on the Tertiary Man 365-874 Index ........... 375-885 LIST OF ILLUSTKATIONS. FIG. PAGE 1. Zermatt Glacier 2 2. Formation of veined structure 3 3, 4. Formation of marginal fissures and veins ... 4 5. Fissures and seracs 4 6. Section across glacial valley, showing old lateral moraines . 5 7. Mont Blanc glacier region 10 8. Svartisen Glacier 13 9. Floating berg 18 10. Iceberg in the Antarctic Ocean 20 11. Map of southeastern Alaska 32 13. Map of Glacier Bay, Alaska 35 18. Front of Muir Glacier 26 14. Map of glaciers in the St. Blias Alps 31 15. Map of Greenland 33 16. Diagram showing the character of glacial motion . . 43 17. Line of most rapid glacial motion 45 18. Diagram showing retardation of the bottom of a glacier . 46 19. Bed-rock scored with glacial marks 52 30. Scratched stone from the till of Boston .... 54 31. Typical section of till in Seattle, Wash 55 33. Ideal section showing how the till overlies the stratified rooks 56 33. Vessel Rock, a glacial boulder 56 a4. Map of RhSne Glacier 58 35. Conglomerate boulder found in Boone County, Ky. . . 63 26. MoheganRock 72 37. Drumlins in GofEstown, N. H 78 28. Map of drumlins in the vicinity of Boston .... 75 29. Section of kame 77 30. Map of kames in Andover, Mass 78 2 XXX Man and the glacial period. FI&. PAGE 31. Longitudinal kames near Hingham, Mass 79 32. Map showing the kames of Maine and southeastern New Hampshire 81 83. Western face of the Kettle Moraine near Eagle, Wis. . 99 34. Section of the east-and-west glacial furrows on Kelly's Island 103 35. Same as the preceding 105 36. Section of till near Germantown, Ohio .... 108 37. Moraines of Grape Creek, Col 123 38. Map of North America in the Ice period .... 137 39. Quartzite boulder on Mont Laohat 128 40. Map showing glaciated areas in North America and Europe 130 41. Maps showing lines of debris extending from the Alps into the plains of the Po 134 43. Section of the Cefn Cave 148 43. Map showing moraine between Speeton and Plamborough 156 44. Diagram-section near Cromer 166 45. Section through the westerly chalk bluff at Trimingham, Norfolk 162 46. Section across Wales 178 47. Section of cliff at Plamborough Head 176 48. Enlarged section of the shelly sand and surrounding clay at B in preceding figure 177 49. Map showing the glaciated area of Europe .... 184 50. Map showing old channel and mouth of the Hudson . . 195 51. New York Harbor in preglacial times 197 53. Section across the valley of the Cuyahoga River . . . 300 53. Map of Mississippi River from Port Snelling to Minne- apolis 309 54. Map showing the effect of the glacial dam at Cincinnati . 313 55. Map of Lake Erie-Ontario 319 56. Map of Cuyahoga Lake 331 57. Section of the lake ridges near Sandusky, Ohio . . 233 58. Map showing stages of recession of the ice in Minnesota . 335 59. Glacial terrace on Raccoon Creek, in Ohio .... 837 60. Ideal section across a river-bed in drift region . . . 839 61. Map of Lakes Bonneville and Lahontan .... 834 63. Parallel roads of Glen Roy 239 63. Map showing glacial terraces on the Delaware and Schuyl- kill Rivers 243 ]j1ST of illustrations. xxxi FIQ. PAGE 64. PalaBolith found by Abbott in New Jersey .... 244 65. Section across the Delaware River at Trenton, N. J. . . 245 66. Section of the Trenton gravel 246 67. Face view of argillite implement found by Dr. C. C. Ab- bott in 1876 247 68. Argillite implement found by Dr. C. C. Abbott, March, 1879 348 69? Chipped pebble of black chert found by Dr. C. L. Metz, October, 1885 349 70. Map showing glaciated area in Ohio 250 71. PalsBoliths from Newcomerstown and Amiens (face view) . 252 72. Bdge view of the preceding 253 73. /Section across the Mississippi Valley at Little Falls, Minn. . 354 74. Quartz implement found by Miss F. B. Babbitt, 1878, at Little Falls, Minn 355 75. Argillite implement found by H. T. Cresson, 1887 . . 359 76. General view of Baltimore and Ohio Railroad cut, near Claymont, Del 260 77. Section across valley of the Somme 263 78. Mouth of Kent's Hole 368 79. Bngis skull (reduced) 274 80. Comparison of forms of skulls . . ... 276 81. Skull of the Man of Spy 377 83. Tooth of Maohairodus neogaeus 281 83. Perfect tooth of an Blephas 281 84. Skull of Hyena spelaea 282 85. Celebrated skeleton of mammoth in St. Petersburg Mu- seum ......■.••• 283 86. Molar tooth of mammoth 284 87. Tooth of Mastodon Americanus .... . 284 88. Skeleton of Mastodon Americanus 386 89. Skeleton of Rhinoceros tichorhinus . ... 287 90. Skull of cave-bear- • . 287 91. Skeleton of the Irish elk 288 92. Musk-sheep 289 93. Reindeer 390 94. Section across Table Mountain, Tuolumne County, Cal. . 394 95. Calaveras skull .... .... 395 96. Three views of Nampa image, drawn to scale . . . 298 97. Map showing Pocatello, Nampa, and the valley of Snake River 399 xxxii MAN AND THE GLACIAL PERIOD. FIG. PAGttB 98. Section across the channel of the Stanislaus Eiver . . 300 99. Diagram showing effect of precession .... 308 100. Map showing course of currents in the Atlantic Ocean . 314 101. Map showing how the land clusters about the north pole . 319 102. Diagram showing oscillations of land-surfaee and ice- surface during the Grlacial epoch 323 103. Diagram of eccentricity and precession .... 333 104. Map of the Niagara River below the Falls . . .334 105. Section of strata along the Niagara Gorge .... 336 106. Map showing the recession of the Horseshoe Palls since 1842 338 107. Section of kettle-hole near Pomp's Pond, Andover, Mass. 345 108. Flint-flakes collected by Abbe Bourgeois .... 368 MAPS. TO FACE PAGE Contour and glacial map of the British Isles . Frontispiece. Map showing the glacial geology of the United States . . 66 Map of glacial movements in France and Switzerland . . 133 MAN AND THE GLACIAL PERIOD. CHAPTEE I. INTRODUCTORY. That glaciers now exist in the Alps, in the Scandi- navian range, in Iceland, in the Himalayas, in New Zea- land, in Patagonia, and in the mountains of Washington, British Columbia, and southeastern Alaska, and that a vast ice-sheet envelops Greenland and the Antarctic Con- tinent, are statements which can be verified by any one who will take the trouble to visit those regions. That, at a comparatively recent date, these glaciers extended far beyond their present limits, and that others existed upon the highlands of Scotland and British America, and at one time covered a large part of the British Isles, the whole of British America, and a considerable area in the northern part of the United States, are inferences drawn from phenomena which are open to every one's observa- tions. That man was in existence and occupied both Eu- rope and America during this great expansion of the northern glaciers is proved by evidence which is now be- yond dispute. It is the object of the present volume to make a concise presentation of the facts which have been rapidly accumulating during the past few years relating to the Glacial peribd and to its connection with human history. Before speaking of the number and present extent of existing glaciers, it will be profitable, however, to devote a little attention to the definition of terms. 2 MAN AND THE GLACIAL PERIOD. A glacier is a mass of ice so situated and of such size as to have motion in itself. The conditions determining the Fig. L— Zermatt Glacier (Agassiz). character and rate of this motion will come up for state- ment and discussion later. It is sufficient here to say that ice has a capacity of movement similar to that possessed by such plastic substances as cold molasses, wax, tar, or cooling lava. The limit of a glacier's motion is determined by the forces which fix the point at which its, final melting takes place. This will therefore depend upon both the warmth of the weather and upon the amount of ice. If the ice is abundant, it will move farther into the region of warm temperature than it will if it is limited in supply. Upon ascending a glacier far enough, one reaches a INTRODUCTORY. 3 comparatively motionless part corresponding to the lake out of which a river often flows. Technically this is called the nevL Glacial ice is formed from snow where the annual fall is in excess of the melting power of the sun at that point. Through the influence of pressure, such as a boy applies to a snow-ball (but which in the neve field arises from the weight of the accumulating mass), the lower strata of the neve are gradually transformed into ice. This process is also assisted by the moisture which percolates through the snowy mass, and which is furnished both by the melting of the surface snow and by occasional rains. The division between the neve and the glacier proper is not always easily determined. The beginnings of the glacial movement — that is, of the movement of the ice-stream flowing out of the nhe field — are somewhat like the begin- nings of the movement of the water from a great lake into its outlet. The neve is the reservoir from which the glacier gets both its supply of ice and the impulse which gives it its first movement. There can not be a glacier without a neve field, as there can not be a river without a drainage basin. But there may be a neve field without a glacier — that is, a basin may be partially filled with snow which never melts completely away, while the equi- librium of forces is such that the ice barely reaches to the outlet from which the tongue-like pro- jection (to which the name glacier would be applied) fails to emerge '''\S;nlf'^'^S^\^:J^T^y only because of the lack of mate- f^Xanc^hes!" ^''"'"°'' "' rial. A glacier is characterised by both veins and fissures. The veins give it a banded or stratified appearance, blue alternating with lighter- coloured portions of ice. As these MAN AND THE GLACIAL PBBIOD. / I r Pig. 4. bands are not arranged with any apparent uniformity in the glacier, their explanation has given rise to much dis- cussion. Sometimes the veins are horizontal, sometimes vertical, and at other times at an angle with the line of motion. On close investigation, however, it is found that the veins are always at right angles to the line of greatest pressure. This leads to the conclusion that pressure is the cause of the banded structure. The blue strata in the ice are those from which the particles of air have been expelled by pressure ; the lighter portions are those in which the par- ticles are less thorough- ly compacted. Snow is but pulverized ice, and differs in colour from the compact mass for the same reason that al- most all rocks and min- erals change their colour when ground into a powder. The fissures, which, when of large size, are called crevasses, are formed in those portions of a glacier where, from some cause, the ice is subjected to slight tension. This occurs especially where, through irregularities in the bot- tom, the slope of the descent is increased. The ice, then, instead of moving in a continuous stream at the top, cracks open along the line of tension, and wedge-shaped fissures are formed ex- tending from the top down to a greater or less distance, according to the degree of tension. Usu- ally, however, the ice remains continuous in the lower Figs. 3, 4.— Illustrate the formation of mar- ginal fissures and veins. Fig. 5. — c, c, show fissures and seracs where the glacier moves down the steeper portion of its incline ; «, «, show the vertical structure produced by pressure on the gentler slopes. INTRODUCTORY. 5 strata, and when the slope is diminished the pressure re- unites the faces of the fissure, and the surface becomes again comparatively smooth. Where there are extensive areas of tension, the surface of the ice sometimes becomes exceedingly broken, presenting a tangled mass of towers, domes, and pinnacles of ice called seracs. Like running water, moving ice is a powerful agent in transporting rocks and earthy debris of all grades of fineness ; but, owing to the different consistencies of ice and water, there are great differences in the mode and result of transportation by them. While water can hold in suspension only the very finest material, ice can bear upon its surface rocks of the great- ^,^_, ,,--'' est magnitude, and ^^^ *"'n JI can roll or shove ^ak.™,-''' ''~-- j^M along under it ^^«a, A^ J&. !kl^^^ boulders and peb- ^k^^'^ ^^^^^^ bles which would ^ JK be unaffected ex- p,s. e— section across Glacial Valley, showing old Cept by torrential Lateral Moraines. currents of water. We find, therefore, a great amount of earthy material of all sizes upon the top of a glacier, which has reached it very much as debris reaches the bed of a river, namely, by falling down upon it from overhanging cliffs, or by land-slides of greater or less extent. Such material coming into a river would either disappear be- neath its surface, or would form a line of debris along the banks; in both cases awaiting the gradual erosion and transportation which running water is able to effect. But, in case of a glacier, the material rests upon the surface of the ice, and at once begins to partake of its motion, while successive accessions of material keep up the supply at any one point, so as to form a train of boulders and other debris, extending below the point as far as the glacial motion continues. 6 MAN AND THE GLACIAL PERIOD. Such a line of debris is called a moraine. When it forms along the edge of the ice, it is called a lateral moraine. It is easy to see that, where glaciers come out from two valleys which are tributary to a larger valley, their inner sides must coalesce below the separating prom- ontory, and the two lateral moraines will become united and will move onward in the middle of the surface of the glacier. Such lines of debris are called medial moraines. These are characteristic of all extensive glaciers formed by the union of tributaries. There is no limit to the number of medial moraines, except in the number of tributaries. A medial moraine, when of sufficient thickness, pro- tects 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 debris, sliding down the slanting sides as the ice slowly wastes away Large blocks of stone in the same manner protect the ice from melting underneath, and are found standing on pedestals of ice, often several feet in height. An in- teresting feature of these blocks is that, when the pedestal fails, the block uniformly falls towards the sun, since that is the side on which the melting has proceeded most rapidly. If the meteorological forces are so balanced that the foot of a glacier remains at the same place for any great length of time, there must be a great accumulation of earthy debris at the stationary point, since the motion of the ice is constantly bearing its lines of lateral and medial moraine downwards to be deposited, year by year, at the melting line along the front. Such accumulations are called terminal moraines, and the process of their formation may be seen at the foot of almost any large glacier. The pile of material thus con- fusedly heaped up in front of some of the larger glaciers of the world is enormous. INTKODUCTORY. 7 The melting away of the lower part of a glacier gives rise also to several other characteristic phenomena. Where the foot of a glacier chances to be on comparatively level land, the terminal moraine often covers a great extent of ice, and protects it from melting for an indefinite period of time. When the ice finally melts away and removes the support from the overlying morainic debris, this settles down in a very irregular manner, leaving enclosed depres- sions to which there is no natural outlet. These depres- sions, from their resemblance to a familiar domestic uten- sil, are technically known as kettle- holes. The terminal moraines of ancient glaciers may often be traced by the relative abundance of these kettle-holes. The streams of water arising both from the rainfall and from the melting of the ice also produce a peculiar effect about the foot of an extensive glacier. Sometimes these streams cut long, open channels near the end of the glacier, and sweep into it vast quantities of morainic mate- rial, which is pushed along by the torrential current, and, after being abraded, rolled, and sorted, is deposited in a delta about its mouth, or left stranded in long lines be- tween the ice- walls which have determined its course. At other times the stream has disappeared far back in the glacier, and plunged into a crevasse (technically called a motilin), whence it flows onwards as a subglacial stream. But in this case the deposits might c}©B^ resemble those of the previous description. In both cases, when the ice has finally melted away, peculiar ridge-like deposits of sorted material remain, to mark the temporary line of drainage. These exist abundantly in most regions which have been covered with glacial ice, and are referred to in Scotland as Tcames, in Ireland as eshers, and in Sweden as osars. In this volume we shall call them hames, and the deltas spread out in front of them will be referred to as kame-plains. With this preliminary description of glacial phenome- 8 MAN AND THE GLACIAL PERIOD. na, we will proceed to give, first, a brief enumeration and description of the ice-fields which are still existing in the world ; second, the evidences of the former existence of far more extensive ice-fields ; and, third, the relation of the Glacial period to some of the vicissitudes which have attended the life of man in the world. The geological period of which we shall treat is vari- ously designated by different writers. By some it is simply called the " post- Tertiary," or " Quaternary " ; by others the term " post- Pliocene " is used, to indicate more sharply its distinction from the latter portion of the Tertiary period ; by others this nicety of distinction is expressed by the term " Pleistocene." But, since the whole epoch was peculiarly characterised by the presence of glaciers, which have not even yet wholly disappeared, we may properly refer to it altogether under the descriptive name of " Glacial " period. CHAPTBE II. EXISTING GLACIERS. In Europe. — Our specific account of existing glaciers naturally begins with those of the Alps, where Hugi, Oharpentier, Agassiz, Forbes, and Guyot, before the mid- dle of this century, first brought clearly to light the reality and nature of glacial motion. According to Professor Heim, of Ziirich, the total area covered by the glaciers and ice-fields of the Alps is up- wards of three thousand square kilometres (about eleven hundred square miles). The Swiss Alps alone contain nearly two-thirds of this area. Professor Heim enumer- ates 1,155 distinct glaciers in the region. Of these, 144 are in Prance, 78 in Italy, 471 in Switzerland, and 462 in Austria. Desor describes fourteen principal glacial districts in the Alps, the westernmost of which is that of Mont Pel- voux, in Dauphiny, and the easternmost that in the vicin- ity of the Gross Glockner, in Carinthia. The most im- portant of the Alpine systems are those which are grouped around Mont Blanc, Monte Eosa, and the Finsteraarhorn, the two former peaks being upwards of fifteen thousand feet in height, and the latter upwards of fourteen thou- sand. The area covered by glaciers and snow-fields in the Bernese Oberland, of which Finsteraarhorn is the culmi- nating point, is about three hundred and fifty square kilo- metres (a hundred square miles), and contains the Aletsch Glacier, which is the longest in Europe, extending twenty- one kilometres (about fourteen miles) from the weve-field 10 MAN AND THE GLACIAL PERIOD. n 05" i § 1^ I EXISTING GLACIERS. H to its foot. The Mer de Glace, which descends from Mont Blanc to the valley of Chamounix, has a length of about eight miles below the mvS-&eld. In all, there are esti- mated to be twenty-four glaciers in the Alps which are upwards of four miles long, and six which are upwards of eight miles in length. The principal of these are the Mer de Glace, of Chamounix, on Mont Blanc; the Gorner Glacier, near Zermatt, on Monte Rosa ; the lower glacier of the Aar, in the Bernese Oberland; and the Aletsch Glacier and Glacier of the Rhdne, in Vallais; and the Pasterzen, in Carinthia. These glaciers adjust themselves to the width of the valleys down which they flow, in some places being a mile or more in width, and at others contracting into much narrower compass. The greatest depth which Agassiz was able directly to measure in the Aar Glacier was two hundred and sixty metres (five hundred and twenty-eight feet), but at another point the depth was estimated by him to be four hundred and sixty metres (or fifteen hun- dred and eighty-four feet). The glaciers of the Alps are mostly confined to the northern side and to the higher portions of the mountain- chain, none of them descending below the level of four thousand feet, and all of them varying slightly in extent, from year to year, according as there are changes in the temperature and in the amount of snow-fall. The Pyrenees, also, still maintain a glacial system, but it is of insignificant importance. This is partly because the altitude is much less than that of the Alps, the cul- minating point being scarcely more than eleven thousand feet in height. Doubtless, also, it is partly due to the narrowness of the range, which does not provide gathering- places for the snow sufficiently extensive to produce large glaciers. The snow-fall also is less upon the Pyrenees than upon the Alps. As a consequence of all these con- ditions, the glaciers of the Pyrenees are scarcely more 12 MAN AND THE GLACIAL PERIOD. than stationary weve'-fields lingering upon the north side of the range. The largest of these is near BaguSres de Luehon, and sends down a short, river-like glacier. In Scandinavia the height of the mountains is also much less than tliat of the Alps, but the moister climate and the more northern latitude favours the growth of glaciers at a much lower level North of the sixty-second degree of latitude, the plateaus over five thousand feet above the sea pretty generally are gathering-places for glaciers. From the Justedal a snow-field, covering five hundred and eighty square miles, in latitude 62°, twenty- four glaciers push outwards towards the German Sea, the largest of which is five miles long and three-quarters of a mile wide. The Fondalen snow-field, between latitudes 66° and 67°, covers an area about equal to that of the Justedal ; but, on account of its more northej-n position, its glaciers descend through the valleys quite to the ocean- level. The Folgofon snow-field is still farther south, but, though occupying an area of only one hundred square miles, it sends down as many as three glaciers to the sea- level. The total area of the Scandinavian snow-fields is about five thousand square miles. In Sweden Dr. Svenonius estimates that there are, between latitudes 67° and 68^°, twenty distinct groups of glaciers, covering an area of four hundred square kilo- metres (one hundred and forty-four square miles), and he numbers upwards of one hundred distinct glaciers of small size. As is to be expected, the large islands in the Polar Sea north of Europe and Asia are, to a great extent, covered with neve-&e\ds, and numerous glaciers push out from them to the sea in all directions, discharging their surplus ice as bergs, which float away and cumber the waters with their presence in many distant places. The island of Spitzbergen, in latitude 76° to 81°, is favourably situated for the production of glaciers, by EXISTING GLACIERS. 13 reason both of its high northern latitude, and of its rela- tion to the Gulf Stream, which conveys around to it an excessive amount of moisture, thus ensuring an excep- Fm. 8. — The Svartisen Glacier on the west coast of Norway, just within the Arc- tic circle, at the head of a fiord ten miles from the ocean. The foot of the Glacier is one mile wide, and a qnarter of a mile back from the water. Ter- minal moraine in front. (Photographed by Dr. L. C. Warner.) tionally large snow-fall over the island. The mountainous character of the island also favours the concentration of the ice-movement into glaciers of vast size and power. Still, even here, much of the land is free from snow and ice in summer. But upon the northern portion of the island there is an extensive table-land, upwards of two thousand feet above the sea, over which the ice-field is continuous. Four great glaciers here descend to tide-wa- ter in Magdalena Bay. The largest of these presents at the front a wall of ice seven thousand feet across and three hundred feet high ; but, as the depth of the water is not 14 MAN AND THE GLACIAL PERIOD. great, few icebergs of large size break off and float away from it. Nova Zembla, though not in quite so high latitude, has a lower mean temperature upon the coasts than Spitz- bergen. Owing to the absence of high lands and moun- tains, however, it is not covered with perpetual snow, much less with glacial ice, but its level portions are "carpeted with grasses and flowers," and sustain exten- sive forests of stunted trees. Franz-Josef Land, to the north of Nova Zembla, both contains high mountains and supports glaciers of great size. Mr. Payer conducted a sledge party into this land in 1874, and reported that a precipitous wall of glacial ice, " of more than a hundred feet in height, formed the usual edge of the coast." But the motion of the ice is very slow, and the ice coarse-grained in structure, and it bears a small amount only of morainic material. So low is here the line of perpetual snow, that the smaller islands "are covered with caps of ice, so that a cross-section would exhibit a regular flat segment of ice." It is in- teresting to note, also, that " many ice-streams, descend- ing from the high neve plateau, spread themselves out over the mountain-slopes," and are not, as in the Alps, confined to definite valleys. Iceland seems to have been properly named, since a single one of the snow-fields — that of Vatnajokiill, with an extreme elevation of only six thousand feet — is esti- mated by Helland to cover one hundred and fifty Nor- wegian square miles (about seven thousand English square miles), while five other ice-fields (the Langjokiill, the Hofsjokiill, the MyrdalsjokuU, the Drangajokiill, and the Glamujokiill) have a combined area of ninety-two Nor- wegian or about four thousand five hundred English square miles. The glaciers are supposed by Whitney to have been rapidly advancing for some time past. In Asia. — Notwithstanding its lofty mountains and its EXISTING GLACIERS. 15 great extent of territory lying in high latitudes, glaciers are for two reasons relatively infrequent : 1. The land in the more northern latitudes is low. 2. The dryness of the atmosphere in the interior of the continent is such that it unduly limits the snow-fall. Long before they reach the central plateau of Asia, the currents of air which sweep over the continent from the Indian Ocean have parted with their burdens of moisture, having left them in a snowy mantle upon the southern flanks of the Himalayas. As a result, we have the extensive deserts of the interior, where, on account of the clear atmosphere, there is not snow enough to resist continuously the intense activity of the unobstructed rays of the sun. In spite of' their high latitude and considerable eleva- tion above the sea-level, glaciers are absent from the Ural Mountains, for the range is too narrow to afford neve- fields of sufficient size to produce glaciers of large ex- tent. The Caucasus Mountains present more favourable con- ditions, and for a distance of one hundred and twenty miles near their central portion have an average height of 12,000 feet, with individual peaks rising to a height of 16,000 feet or more ; but, owing to their low latitude, the line of perpetual snow scarcely reaches down to the 11,- 000-foot level. So great are the snow-fields, however, above this height that many glaciers push their way down through the narrow mountain-gorges as far as the 6,000- foot level. The Himalaya Mountains present many favourable con- ditions for the development of glaciers of large size. The range is of great extent and height, thus affording ample gathering-places for the snows, while the relation of the mountains to the moisture-laden winds from the Indian Ocean is such that they enjoy the first harvest of the clouds where the interior of Asia gets only the gleanings. As is to be expected, therefore, all the great rivers which course 3 16 MAN AND THE GLACIAL PERIOD. through the plains of Hindustan have their rise in large glaciers far up towards the summits of the northern mountains. The Indus and the G-anges are both glacial streams in their origin, as are their larger tributary branches — the Basha, the Shigar, and the Sutlej. Many of the glaciers in the higher levels of the Himalaya Mountains where these streams rise have a length of from twenty-five to forty miles, and some of them are as much as a mile and a half in width and extend for a long distance, with an inclination as small as one de- gree and a half or one hundred and thirty-eight feet to a mile. In the Mustagh range of the western Himalayas there are two adjoining glaciers whose united length is sixty- five miles, and another not far away which is twenty-one . miles long and from one to two miles wide in its upper portion. Its lower portion terminates at an altitude of 16,000 feet above tide, where it is three miles wide and two hundred and fifty feet thick. Oceanica. — Passing eastward to the islands of the Pa- cific Ocean, New Zealand is the only one capable of sup- porting glaciers. Their existence on this island seems the more remarkable because of its low latitude (43° to 45°) ; but a grand range of mountains rises abruptly from the water on the western coast of the southern island, culminating in Mount Cook, 13,000 feet above the sea, and extending for a distance of about one hundred miles. The extent and height of this chain, coupled with the moisture of the winds, which sweep without obstruction over so many leagues of the tropical Pacific, are specially favourable to the production of ice-fields of great extent. Consequently we find glaciers in abundance, some of which are not inferior in extent to the larger ones of the Alps. The Tasman Glacier, described by Haas, is ten miles long and nearly two miles broad at its termination, "the lower portion for a distance of three miles being EXISTING GLACIERS. 17 covered with morainic detritus." The Mueller Glacier is about seven miles long and one mile broad in its lower portion. South America. — In America, existing glaciers are chiefly confined to three principal centres, namely, to the Andes, south of the equator ; to the Cordilleras, north of central California ; and to Greenland. In South America, however, the high mountains of Ecuador sustain a few glaciers above the twelve-thousand- foot level. The largest of these are upon the eastern slope of the mountains, giving rise to some of the branches of the Amazon — indeed, on the flanks of Cotopaxi, Chimbo- razo, and lUinissa there are some glaciers in close proximity to the equator which are fairly comparable in size to those of the Alps. In Chili, at about latitude 35°, glaciers begin to ap- pear at lower levels, descending beyond the six-thou- sand-foot line, while south of this both the increasing moisture of the winds and the decreasing average tem- perature favour the increase of ice-fields and glaciers. Con- sequently, as Darwin long ago observed, the line of per- ' petual snow here descends to an increasingly lower level, and glaciers extend down farther and farther towards the sea, until, in Tierra del Fuego, at about latitude 45°, they begin to discharge their frozen contents directly into the tidal inlets. Darwin's party surveyed a glacier entering the Gulf of Penas in latitude 46° 50', which was fifteen miles long, and, in one part, seven broad. At Eyre's Sound, also, in about latitude 48°, they found immense glaciers coming down to the sea and discharging icebergs of great size, one of which, as they encountered it floating outwards, was estimated to be " at least one hundred and sixty-eight feet in total height." In Tierra del Fuego, where the mountains are only from three thousand to four thousand feet in height and in latitude less than 55°; Darwin reports that " every val- 18 MAN AND THE GLACIAL PERIOD. ley is filled with streams of ice descending to the sea- coast," and that the inlets penetrated by his party pre- sented miniature likenesses of the polar sea. Antarctic Continent.— Oi the so-called Antarctic Con- tinent little is known ; but icebergs of great size are fre- quently encountered up to 58° south latitude, in the direc- tion of Cape Horn, and as far as latitude 33° in the di- rection of Cape of Good Hope. Nearly all that is known about this continent was discoTered by Sir J. C. Boss Fia. 9. — Floating "berg, ehowing the proportions above and under the water. About seven feet under water to one above. during the period extending from 1839 to 1843, when, between the parallels of 70° and 78° south latitude, he encountered in his explorations a precipitous mountain coast, rising from seven thousand to ten thousand feet above tide. Through the valleys intervening between the mountain-ranges huge glaciers descended, and " projected in many places several miles into the sea and terminated in lofty, perpendicular cliffs. In a few places the rocks EXISTING GLACIERS. 19 broke through their icy covering, by which alone we could be assured that land formed the nucleus of this, to appear- ance, enormous iceberg." * Again, speaking of the region in the vicinity of the lofty -volcanoes Terror and Erebus, between ten thou- sand and twelve thousand feet high, the same navigator "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 appear- ance, gradually increasing in height as we got nearer to it, and proving at length to be a perpendicular cliii of ice, between one hundred and fifty and two hundred feet above the level of the sea, perfectly flat and level at the top, and without 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 moun- tains extending to the southward as far as the seventy- ninth degree of latitude. These mountains, being the southernmost land hitherto discovered, I felt great satis- faction 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 determine. 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 barrier." This ice-cliff or barrier was followed by Captain Eoss as far as 198° west longitude, and found to preserve very much the same character during the whole of that dis- tance. On the lithographic view of this great ice-sheet given in Eoss's work it is described as " part of the South Polar Barrier, one hundred and eighty feet above the sea- *, Quoted J)y Whitney in Climatic Changes, p. 314. 20 MAN AND THE GLACIAL PERIOD. level, one thousand feet thick, and four hundred and fifty 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 ap- pearance was astonishing. We perceived a cliff having a uniform elevation of from one hundred to one hundred and fifty feet, forming a long line extending off to the west. . . . Thus for more than twelve hours we had fol- lowed this wall of ice, and found its sides everywhere per- fectly vertical and its summit horizontal. Not the small- est irregularity, not the most inconsiderable elevation, broke its uniformity for the twenty leagues of distance which we followed 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 irregulari- FiG. 10. — Iceberg in the Antarctic Ocean. ties. 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." * North America. — In North America living glaciers * Whitney's Climatic Changes, pp. 315, 316. EXISTING GLACIERS. 21 begin to appear in the Sierra Nevada Mountains, in the vicinity of the Yosemite Park, in central California. Here the conditions necessary for the production of glaciers are favourable, namely, a high altitude, snow-fields of consid- erable extent, and unobstructed exposure to the moisture- laden currents of air from the Pacific Ocean. Sixteen glaciers of small size have been noted among the summits to the east of the Yosemite ; but none of them descend much below the eleven-thousand-foot line, and none of them are over a mile in length. Indeed, they are so small, and their motion is so slight, that it is a question whether or not they are to be classed with true glaciers. Owing to the comparatively low elevation of the Sierra Nevada north of Tuolumne County, California, no other living glaciers are found until reaching Mount Shasta, in the extreme northern part of the State. This is a volcanic peak, rising fourteen thousand five hundred feet above the sea, and having no peaks within forty miles of it as high as ten thousand feet ; yet so abundant is the snow- fall that as many as five glaciers are found upon its north- ern side, some of them being as much as three miles long and extending as low down as the eight-thousand-foot level. Upon the southern side glaciers are so completely absent that Professor Whitney ascended the mountain and remained in perfect ignorance of its glacial system. In 1870 Mr. Clarence King first discovered and described them on the northern side. North of California glaciers characterise the Cascade Kange in increasing numbers all the way to the Alaskan Peninsula. They are to be found upon Diamond Peak, the Three Sisters, Mount Jefferson, and Mount Hood, in Oregon, and appear in still larger proportions upon the flanks of Mount Eainier (or Tacoma) and Mount Baker, in the State of "Washington. The glacier at the head of the White Eiver Valley is upon the north side of Eainier, and is the largest one upon that mountain, reaching Fig. 11.— Map of Southeastern Alaska. The arrow-points mark glacierfi. EXISTING GLACIERS. 23 down to within five thousand feet of the sea-level, and being ten miles or more in length. All the streams which descend the valleys upon this mountain are charged with the milky-coloured water which betrays their glacial origin. In British Columbia, Glacier Station, upon the Cana- dian Pacific Eailroad, in the Selkirk Mountains, is within half a mile of the handsome Illicilliwaet Glacier, while others of larger size are found at no great distance. The interior farther north is unexplored to so great an extent that little can be definitely said concerning its glacial phe- nomena. The coast of British Columbia is penetrated by numerous fi.ords, each of which receives the drainage of a decaying glacier ; but none are in sight of the tourist- steamers which thread their way through the intricate network of channels characterising this coast, until the Alaskan boundary is crossed and the mouth of the Stick- een Eiver is passed. A few miles up from the mouth of the Stickeen, how- ever, glaciers of large size come down to the vicinity of the river, both from the north and from the south, and the attention of tourists is always attracted by the abun- dant glacial sediment borne into the tide- water by the river itself and discolouring the surface for a long distance be- yond the outlet. Northward from this point the tourist is rarely out of sight of ice-fields. The Auk and Patter- son Glaciers are the first to come into view, but they do not descend to the water-level. On nearing Holcomb Bay, however, small icebergs begin to appear, heralding the first of the glaciers which descend beyond the water's edge. Taku Inlet, a little farther north, presents glaciers of great size coming down to the sea-level, while the whole length of Lynn Canal, from Juneau to Chilkat, a distance of eighty miles, is dotted on both sides by conspicuous glaciers and ice-fields. The Davidson Glacier, near the head of the canal, is one of the most interesting for purposes of study. It 24 MAN AND THE GLACIAL PERIOD. comes down from an unknown distance in the western in- terior, bearing two marked medial moraines upon its sur- face. On nearing tide-level, the valley through which it flows is about three-quarters of a mile in width ; but, after emerging from the confinement pf the valley, the ice spreads out over a fan-shaped area until the width of its front is nearly three miles. The supply of ice not be- ing sufficient to push the front of the glacier into deep water, equilibrium between the forces of heat and cold is established near the water's edge. Here, as from year to year the ice melts and deposits its burdens of earthy debris, it has piled up a terminal moraine which rises from two hundred to three hundred feet in height, and is now cov- ered with evergreen trees of considerable size. From Chilkat, at the head of Lynn Canal, to the sources of the Yukon River, the distance is only thirty-five miles, but the intervening mountain-chain is several thousand feet in height and bears numerous glaciers upon its seaward side. About forty miles west of Lynn Canal, and separated from it by a range of mountains of moderate height, is Glacier Bay, at the head of one of whose inlets is the Muir Glacier, which forms the chief attraction for the great number of tourists that now visit the coast of south- eastern Alaska during the summer season. This glacier meets tide-water in latitude 58° 50', and longitude 136° 40' west of Greenwich. It received its name from Mr. John Muir, who, in company with Eev. Mr. Young, made a tour of the bay and discovered the glacier in 1879. It was soon found that the bay could be safely navigated by vessels of large size, and from that time on tourists in increasing number have been attracted to the region. Commodious steamers now regularly run close up to the ice-front, and lie-to for several hours, so that the passen- gers may witness the " calving " of icebergs, and may climb upon the sides of the icy stream and look into its EXISTING GLACIERS. 25 deep crevasses and out upon its corrugated and broken surface. The first persons who found it in their way to pay more than a tourist's visit to this interesting object were Fig. 12.— Map of Glacier Bay, Alaska, and its surroundings. Arrow-points indicate glaciated area. Eev. J. L. Patton, Mr. Prentiss Baldwin, and myself, who spent the entire month of August, 1886, encamped at the 26 MAX AND THE GLACIAL PERIOD. foot of the glacier, conducting such observg-tions upon it as weather and equipment permitted. From that time Fig. 13.— Shows central part of the front of Muir Ghicier one half mile distant. Near the lower left hand corner the ice is seen one mile distant resting for about one half mile on gravel which it had overrun. The ice is now retreat- ing in the channel. (From photograph.) till the summer of 1890 no one else stopped oil from the tourist steamers to bestow any special study upon it. But during this latter season Mr. Muir retu-rned to the scene of his discovered wonder, and spent some weeks in exploring the interior of the great ice-field. During the same season, also. Professors II. F. Reid and H. Gushing, with a well-equipped party of young men, spent two months or more in the same field, conducting observa- tions and experiments, of various kinds, relating to the extent, the motion, and the general behaviour of the vast mass of moving ice. The main body of the Muir Glacier occupies a vast EXISTING GLACIERS. 27 amphitheatre, with diameters ranging from thirty to forty miles, and covers an area of about one thousand square miles. From one of the low mountains near its mouth I could count twenty-six tributary glaciers which came to- gether and became confluent in the main stream of ice. Nine medial moraines marked the continued course of as many main branches, which becoming united formed the grand trunk of the glacier. Numerous rocky eminences also projected above the surface of the ice, like islands in the sea, corresponding to what are called " nunataks " in Greenland. The force of the ice against the upper side of these rocky prominences is such as to push it in great masses above the surrounding level, after the analogy of waves which dash themselves into foam against similar obstructions. In front of the nunataks there is uni- formly a depression, like the eddies which appear in the current below obstacles in running water. Over some portions of the surface of the glacier there is a miniature river system, consisting of a main stream, with numerous tributaries, but all flowing in channels of deep blue ice. Before reaching the front of the glacier, however, each one of these plunges down into a crevasse, or moulin, to swell the larger current, which may be heard rushing along in an impetuous course hundreds of feet beneath, and far out of sight. The portion of the glacier in which there is the most rapid motion is char- acterised by innumerable crags and domes and pinnacles of ice, projecting above the general level, whose bases are separated by fissures, extending in many cases more than a hundred feet below the general level. These irregu- larities result from the combined effect of the differential motion (as illustrated in the diagram on page 4), and the influence of sunshine and warm air in irregularly melting the unprotected masses. The description given in our introductory chapter of medial moraines and ice- pillars is amply illustrated everywhere upon the surface 28 MAN AND THfi GLACIaL PErIOD. of the Muir Glacier. I measured one block of stone which was twenty feet square and about the same height, standing on a pedestal of ice three or four feet high. The mountains forming the periphery of this amphi- theatre rise to a height of several thousand feet ; Mount Pairweather, upon the northwest, from whose flanks prob- ably a portion of the ice comes, being, in fact, more than fifteen thousand feet high. The mouth of the amphi- theatre is three miles wide, in a line extending from shoulder to shoulder of the low mountains which guard it. The actual water-front where the ice meets tide-water is one mile and a half.* Here the depth of the inlet is so great that the front of the ice breaks off in icebergs of large size, which float away to be dissolved at their leisure. At the water's edge the ice presents a, perpendicular front of from two hundred and fifty to four hundred feet in height, and the depth of the water in the middle of the inlet immediately in front of the ice is upwards of seven hundred feet ; thus giving a total height to the precipitous front of a thousand feet. The formation of icebergs can here be studied to admirable advantage. During the month in which we encamped in the vicinity the process was going on con- tinuously. There was scarcely an interval of fifteen minutes during the whole time in which the air was not rent with the significant boom connected with the " calv- ing " of a berg. Sometimes this was occasioned by the separation of a comparatively small mass of ice from near the top of the precipitous wall, which would fall into the water below with a loud splash. At other times I have seen a column of ice from top to bottom of the precipice split off and fall over into the water, giving rise to great waves, which would lash the shore with foam two miles below. * These are the measurements of Professor Reid. In my former volume I have given the dimensions as somewhat smaller. EXISTING GLACIERS. 29 This manner of the production of icebergs difEers from that which has been ordinarily represented in the text-books, but it conforms to the law of glacial motion, which we will describe a little later, namely, that the upper strata of ice move faster than the lower. Hence the tendency is constantly to push the upper strata for- wards, so as to produce a perpendicular or even projecting front, after the analogy of the formation of breakers on the shelving shore of a large body of water. Evidently, however, these masses of ice which break off from above the water do not reach the whole distance to the bottom of the glacier below the water ; so that a projecting foot of ice remains extending to an indefinite distance underneath the surface. But at occasional in- tervals, as the superincumbent masses of ice above the surface fall off and relieve the strata below of their weight, these submerged masses suddenly rise, often shooting up considerably higher than they ultimately remain when coming to rest. The bergs formed by this latter process often bear much earthy material upon them, which is carried away with the floating ice, to be deposited finally wherever the melting chances to take place. Numerous opportunities are furnished about the front and foot of this vast glacier to observe the manner of the formation of hames, kettle-holes, and various other irregu- lar forms into which glacial debris is accustomed to ac- cumulate. Over portions of the decaying foot of the glacier, which was deeply covered with morainic debris, the supporting ice is being gradually removed through the influence of subglacial streams or of abandoned tunnels, which permit the air to exert its melting power undel-- neath. In some places where old moulins had existed, the supporting ice is melting away, so that the superincumbent mass of sand, gravel, and boulders is slowly sliding into a common centre, like grain in a hopper. This must pro- duce a conical hill, to remain, after the ice has all melted 30 MAN AND THE GLACIAL PERIOD. away, a mute witness of the impressive and complicated forces which have been so long in operation for its pro- duction. In other places I have witnessed the formation of a long ridge of gravel by the gradual falling in of the roof of a tunnel which had been occupied by a subglaciai stream, and over which there was deposited a great amount of morainic material. As the roof gave way, this was constantly falling to the bottom, inhere, being' exempt from further erosive agencies, it must remain as a gravel ridge or kame. In other places, still, there were vast masses of ice covering many acres, and buried beneath a great depth of morainic material which had been swept down upon it while joined to the main glacier. In the retreat of the ice, however, these masses had become isolated, and the sand, gravel, and boulders were sliding down the wasting sides and forming long ridges of debris along the bottom, which, upon the final melting of the ice, will be left as a complicated network of ridges and knolls of gravel, en- closing an equally complicated nest of kettle-holes. Beyond Cross Sound the Pacific coast is bounded for several hundred miles by the magnificent semicircle of mountains known as the St. Elias Alps, with Mount Cril- lon at the south, having an elevation of nearly sixteen thousand feet, and St. Elias in the centre, rising to a greater height. Everywhere along this coast, as far as the Alaskan Peninsula, vast glaciers come down from the mountain-sides, and in many cases their precipitous fronts form the shore-line for many miles at a time. Icy Bay, just to the south of Mount St. Elias, is fitly named, on account of the extent of the glaciers emptying into it and the number of icebergs cumbering its waters. In the summer of 1890 a party, under the lead of Mr. I. 0. Russell, of the United States Geological Survey, made an unsuccessful attempt to scale the heights of EXISTING GLACIERS. 31 Mount St. Elias; but the information brought back by them concerning the glaciers of the region amply repaid Fig. 14.— By the courtesy of the National Geographical Society. them for their toil and expense, and consoled them for the failure of their immediate object. Leaving Yakutat Bay, and following the route indi- cated upon the accompanying map, they travelled on gla- cial ice almost the entire distance to the foot of Mount St. Elias. The numerous glaciers coming down from the summit of the mountain-ridge become confluent nearer the shore, and spread out over an area of about a thousand square miles. This is fitly named the Malaspina Glacier, after the Spanish explorer who discovered it in 1793. It is not necessary to add further particulars concern- 32 MAN AND THE GLACIAL PERIOD. ing the results of this expedition, since they are so similar to those already detailed in connection with the Muir Glacier. A feature, however, of special interest, pertains to the glacial lakes which are held in place by the glacial ice at an elevation of thousands of feet above the sea. One of considerable size is indicated upon the map just south of what was called Blossom Island, which, however, is not an island, but simply a nunatak, the ice here surrounding a considerable area of fertile land, which is covered with dense forests and beautified by a brilliant assemblage of flowering plants. In other places considerable vegetation was found upon the surface of moraines, which were prob- ably still in motion with the underlying ice. Greenland. — The continental proportions of Green- land, and the extent to which its area is covered by glacial ice, make it by far the most important accessible field for glacial observations. The total area of Greenland can not be less than five hundred thousand square miles — equal in extent to the portion of the United States east of the Mis- sissippi 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 towards 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 prob- lem that Baron Nordenskiold 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 continuous ice-field. Elvers were flowing in channels upon the surface like those cut on land in hori- zontal strata of shale or sandstone, only that the pure deep blue of the ice- walls was, by comparison, infinitely more beautiful. These rivers were not, however, perfectly con- tinuous. After flowing for a distance in channels on the EXISTING GLACIBKS. 33 I '«.7 „ <«> i..c'a ■~> fOj ■'•\j' X2- Fia. 15. — Map of Greenland. The arrow-points mark the margin of the ice-field. 4 84 MAN AND THE GLACIAL PERIOD. 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 ex- plorer, " we could hear on every side a peculiar subter- ranean hum, proceeding from rivers flowing within the ice ; and occasionally 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 bottomless 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 two thousand feet beneath, on which the glacier rested."* At the end of the eighteen days Nordenskiold found himself about a hundred and fifty miles from his starting- point, and about five thousand feet above the sea. Here the party rested, and sent two Eskimos forward on shidor — a kind of long wooden skate, with which they could move rapidly over the ice, notwithstanding the numerous small, circular holes which everywhere 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 a hundred and fifty miles, and attained an altitude of six thousand feet. The ice is reported as rising in distinct terraces, and as seemingly boundless beyond. If this is the case, two hundred 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 * Geological Magazine, vol. ix, pp. 393, 899. EXISTING GLACIERS. 35 there is no continuous covering of ice. In south Green- land the continuous ice-sheet is reached about thirty miles back from the shore. A summary of the results of Greenland exploration was given by Dr. Eink in 1886, from which it appears that since 1876 one thousand miles of the coast-line have been carefully explored by entering every fiord and at- tempting to reach the inland ice. According to this au- thority — 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-formation here in question is given by comparing it with an inundation. . . . Only the mar- ginal parts show irregularity ; towards the interior the sur- face 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 68^° north latitude it took twenty-four miles before this eleva- tion was attained, in 72|° the same height was arrived at in half the distance. . . . A general movement of the whole mass from the cen- tral regions towards the sea is still continued, but it con- centrates 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 Green- land 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 frag- 36 MAN AND THE GLACIAL PERIOD. ments. Direct measurements of tlie velocity hare now been applied on three first-rate and one second-rate fiords, all situated between 69° and 71° north latitude. The measurements 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 enor- mous bergs over Disco Bay and probably far into the At- lantic, the productive part of the glacier is 4,500 metres (about 2i 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 Torsukatak receives four or five branches of the glacier ; the most productive of them is about 9,000 metres broad (five miles), and moves between sixteen and thirty-two feet per diem. The large Karajak Glacier, about 7,000 metres (four miles) broad, 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 broad (three miles), moved between twenty-four and forty-six feet per diem.* The principal part of our information concerning the glaciers of Greenland north of Melville Bay was obtained by Drs. Kane and Hayes, in 1853 and 1854, while con- ducting an expedition in search of Sir John Franklin and his unfortunate crew. Dr. Hayes conducted another ex- * See Transactions of the Edinburgh Geological Society for Feb- ruary 18, 1886, vol. V, part ii, pp. 286-293. EXISTING GLACIERS. 37 pedition to the same desolate region in 1860, while other explorers have to some extent supplemented their obser- vations. The largest glacier which they saw enters the sea between latitude 79° and 80°, where it presents a pre- cipitous discharging front more than sixty miles in width and hundreds of feet in perpendicular height. Dr. Kane gives his first impressions of this grand gla- cier in the following vivid description : " 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 cliflE 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 in- tensely illuminated by the sun.' But this line of cliff rose in a solid, glassy wall three hundred feet above the water-level, with an unknown, unfathomable depth below it ; and its curved face, sixty miles in length from Cape Agassiz 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 nier de glace — an ice- ocean to the eye, of boundless dimensions. " It was in full sight — the mighty crystal bridge which connects the two continents of America and Greenland. I say continents, for Greenland, however insulated it may ultimately prove to be, is in mass strictly continental. Its least possible axis, measured from Cape Farewell to the line of this glacier, in the neighbourhood of the eightieth parallel, gives a length of more than 1,200 miles, not ma- terially less than that of Australia from its northern to its southern cape. " Imagine, now, the centre of such a continent, occu- pied 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 precipi- 38 MAN AND THE GLACIAL PERIOD. tations of its atmosphere upon its own surface. Imagine this, moving onwards like a great glacial river, seeking outlets at every fiord and valley, rolling icy cataracts into the Atlantic and Greenland seas; and, having at last reached the northern limit of the land that has borne it up, pouring out a mighty frozen torrent into unknown arctic space ! " It is thus, and only thus, that we must form a just conception of a phenomenon like this great glacier. I had looked in my own mind for such an appearance, should I ever be fortunate 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 analogies which Forbes and Studer have developed between the glacier and the river. But I could not comprehend at first this complete substi- tution 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 Arctic 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 con- verted 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 ploughing its way with irresistible march through the crust of an investing sea."* Much less is known concerning the eastern coast of Greenland than about the western coast. For a long time it was supposed that there might be a considerable popu- lation in the lower latitudes along the eastern side. But that is now proved to be a mistake. The whole coast is very inhospitable and difiicult of approach. From lati- * Arctic Explorations in the Years 1853, 1854, and 1855, vol. i, pp. 235-338. EXISTING GLACIERS. 39 tude 65° to latitude 69° little or nothing is known of it. In 1832-'23 Scoresby, Cleavering, and Sabine hasiily ex- plored 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 dangerous. In 1869 and 1870 the second North - German Expedition partly explored the coast between latitude 73° and 77°. Mr. Payer, an ex- perienced Alpine explorer, who accompanied the expedi- tion, reports the country as much broken, and the glaciers as " subordinated in position to the higher peaks, and hav- ing their moraines, both lateral and terminal, like those of the Alpine ranges, and on a still grander scale." Peter- mann Peak, in latitude 73°, is reported as 13,000 feet high. Captain Koldewey, chief of the expedition, found extensive plateaus on the mainland, in latitude 75°, to be " entirely clear of snow, although only sparsely covei'ed with vegetation." The mountains in this vicinity, also, rising to a height of more than 3,000 feet, were free from snow in the summer. Some of the fiords in this vicinity pene- trate the continent through several degrees of longitude. An interesting episode of this expedition was the ex- perience 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 the ship. Prom this, as it slowly floated towards the south through several 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 ap- pearance everywhere 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. P. Nansen, with Lieutenant Sverdrup and four others, was left by a whaler on the ice-pack border- ing the east of Greenland about latitude 65°, and in sight of the coast. For twelve days the party was on the ice- iO MAN AND THE GLACIAL PERIOD. pack floating south, and so actually reached the coast only about latitude 64°. From this point they attempted to cross the inland ice in a northwesterly direction towards Christianshaab. They soon reached a height of 7,000 feet, and were compelled by seyere 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 Godhaab, about the same latitude at which they entered. It thus appears that subsequent investigations have confirmed in a remarkable manner the sagacious conclu- sions made by the eminent Scotch geologist and glacialist Eobert Brown in 1875, soon after his own expedition to the country. " I look upon Greenland and its interior ice-field," he writes, "in the light of a broad-lipped, shallow vessel, but with chinks in the lips here and there, and the glacier like viscous matter in it. As more is poured in, the viscous matter will run over the edges, naturally taking the line of the chinks as its line of outflow. The broad lips of the vessel are the outlying islands or ' outskirts ' ; the viscous matter in the vessel the inland ice, the additional matter continually being poured in in the form of the enormous snow covering, which, winter after winter, for seven or eight months in the year, falls almost continuously on it ; the chinks are the fiords or valleys down which the glaciers, represent- ing the outflowing viscous matter, empty the surplus of the vessel — in other words, the ice floats out in glaciers, overflows the land in fact, down the valleys and fiords of Greenland by force of the superincumbent weight of snow, just as does the grain on the floor of a barn (as admirably described by Mr. Jamieson) when another sackful is emp- tied on the top of the mound already on the floor. ' The floor is flat, and therefore does not conduct the grain in any direction ; the outward motion is due to the pressure EXISTING GLACIERS. 41 of the particles of grain on one another; and, given a floor of infinite extension and a pile of suflBcient amount, the mass would move outward to any distance, and with a very slight pitch or slope it would slide forward along the incline.' To this let me add that if the floor on the mar- gin of the heap of grain was undulating the stream of grain would take the course of such undulations. The want, therefore, of much slope in a country and the ab- sence of any great mountain-range are of very little mo- ment to the movement of land-ice, provided we have snow enough." On another page Dr. Brown had well said that "the country seems only a circlet of islands separated from one another by deep fiords or straits, and bound to- gether on the landward side by the great ice covering which overlies the whole interior. . . . No doubt under this ice there lies land, just as it lies under the sea ; but nowadays none can be seen, and as an insulating medium it might as well be water." In his recently published volumes descriptive of the journey across the Greenland ice-sheet, alluded to on page 39, Dr. Hansen sums up his inferences in very much the same way : " The ice-sheet rises comparatively abruptly from the sea on both sides, but more especially on the east coast, while its central portion is tolerably flat. On the whole, the gradient decreases the farther one gets into the interior, and the mass thus presents the form of a shield with a surface corrugated by gentle, almost imper- ceptible, undulations lying more or less north and south, and with its highest point not placed symmetrically, but very decidedly nearer the east coast than the west." Prom this rapid glance at the existing glaciers of the world we see that a great ice age is not altogether a strange thing in the world. The lands about the south pole and Greenland are each continental in dimensions, and present at the present time accumulations of land-ice so extensive, so deep, and so alive with motion as to pre- 42 MAN AND THE GLACIAL PERIOD. pare our minds for almost anything that may be suggested concerning the glaciated condition of other portions of the earth's surface. The vera causa is sufiBcient to accom- plish anything of which glacialists have ever dreamed. It only remains to enquire what the facts really are and over how great an extent of territory the actual results of gla- cial action may be found. But we will first direct more particular attention to some of the facts and theories con- cerning glacial motion. CHAPTER III. GLACIAL MOTION. That glacial ice actually moves after the analogy of a semi-fluid has been abundantly demonstrated by observa- tion. In the year 1837 Professor Hugi, of Soleure, built a hut far np upon the Aar Glacier in Switzerland, in order to determine the rate of its motion. After three years he found that it had moved 330 feet; after nine years, 2,354 feet ; and after fourteen years Louis Agassiz found that its motion had been 4,713 feet. In 1841 Agassiz began a more accurate series of observation upon the same glacier. Boring holes in the ice, he set across it a row of stakes which, on visiting in 1843, he found to be no longer in a straight line. All had moved down- wards with varying velocity, those near the centre having moved farther than the others. The displacements of the stakes were in order, from side to side, as follows : 160 feet, 335 feet, 369 feet, 345 feet, 310 feet, and 125 feet. Agassiz followed up his observa- tions for six years, and in 1847 published the results in his celebrated work System Glaci^re. But in August, 1841, the distinguished Swiss investi- gator had invited Professor J. D. Forbes, of Edinburgh, to interest himself in solving the problem of glacial motion. In response to this request. Professor Forbes spent three weeks with Agassiz upon the Aar Glacier. Stimulated e great Hhfine Glacier (after Lyell). ,^^g^ ^^^^ ^^^ upwards of two thousand feet above it. But large Alpine boulders are found as high as two thousand feet above the Lake Neuf ch^tel upon the flanks of the Jura Mountains beyond Chasseron (at the point marked G- on the map), and the whole valley is dotted with Alpine boulders. Upon com- paring these with the native rocks in the Alps, Gruyot in many cases was able to determine the exact centres from which they were distributed, and the distribution is such as to demonstrate that glacial ice was the medium of dis- tribution. For example, the dotted lines upon the map indicate the motion of the transporting medium. On ascending the valley of the Rhdne to A, the diminutive representa- tive of the ancient glacier is still found in existence, and * Antiquity of Man, p. 299. SIGNS OP PAST GLACIATIOK. 59 is at work transporting boulders and moraines according to the law of ice-movement. Following down the valley from A, boulders from the head of the Ehone Valley are found distributed as far as B at Martigny, where the val- ley turns at right angles towards the north. It is evident that floating ice in a stream of water would by its momen- tum be carried to the left bank, so that if icebergs were the medium of transportation we should expect to find the boulders from the right-hand side of the Rh6ne Val- ley distributed towards the left end of the great valley of Switzerland — that is, in the direction of Geneva. But, instead, the boulders derived from 0, D, and E, on the Bernese Oberland side, instead of crossing the valley at B, continue to keep on the right-hand side and are dis- tributed over the main valley in the direction of the river Aar. As is to be expected also, the direct northward motion of the ice from B is stronger than the lateral movement to the right and left after it emerges from the mouth of the Eh6ne Valley, at F, and consequently it has pushed for- wards in a straight line, so as to raise the Alpine boulders to a greater height upon the Jura Mountains at G- than anywhere else, the upper limit of boulders at G being 1,500 feet higher than the limits at I or K on the left and right, points distant about one hundred miles from each other. All the boulders to the right of the line from B to G have been derived from the right side of the Rh6ne, while all the boulders to the left of that line have been derived from its left side. A boulder of talcose granite containing 61,000 French cubic feet, measuring about forty feet in one direction, came, according to Charpentier, from the point w, near the head of the Rhone Valley, and must have travelled one hundred and fifty miles to reach its present position. It scarcely needs to be added that the grooves and scratches upon the rocks over the floor of this great valley 60 MAN AND THB GLACIAL PERIOD. of Switzerland indicate a direction of the ice-movement corresponding to that implied in the distribution of boul- ders. Thus, at K upon the map referred to, Lyell reports that the abundant grooves and stri^ upon the polished marble all trend down the valley of the Aar.* Similar facts concerning the transportation of boul- ders have been observed at Trogen, in Appenzel, where boulders derived from Trons, one hundred miles distant, are found to keep upon the left bank of the Rhine, how- ever much the valley may wind about ; and in some places, as at Mayenfeld, it turns almost at right angles, as did the Rhdne at Martigny. Upon reaching the lower country at Lake Constance, these granite blocks from the left side of the valley deploy out upon the same side and do not cross over, as they would inevitably have done had they been borne along by currents of water. In America we do not have quite so easy a field as is presented in Switzerland for the discovery of crucial in- stances showing that boulders have been transported by glacial ice rather than by floating ice, for in Switzerland the glaciated area is comparatively small and the diminu- tive remnants of former glaciers are still in existence, fur- nishing a comprehensive object-lesson of great interest and convincing power. Still, it is not difficult to find decisive instances of glacial transportation even in the broad fields of America which now retain no living rem- nants of the great continental ice-sheet. As every one who resides in or who visits New England knows, boulders are scattered freely over all parts of that region, but for a long time the theory suggested to ac- count for their distribution was that of fioating ice during a period of submergence. One of the most convincing evidences that the boulders were distributed by glacial ice rather than by icebergs is found in Professor C. H. Hitch- * Antiquity of Man, p. 305. SIGNS OP PAST GLACIATION. 61 cock's discovery of boulders on the summit of Mount Washington (over 6,000 feet above the sea), which he was able to identify as derived from the ledges of light grey Bethlehem gneiss, whose nearest outcrop is in JefEerson, several miles to the northwest, and 3,000 or 4,000 feet lower than Mount Washington. However difficult it may be to explain the movement of these boulders by glacial ice, it is not impossible to do so, but the attempt to ac- count for their transportation by floating ice is utterly preposterous. No iceberg could pick up boulders so far beneath the surface of the water, and even if it could ad- vance thus far in its work it could not by any possibility land them afterwards upon the summit of Mount Wash- ington. Among the most impressive instances of boulders evi- dently transported by glacial ice, rather than by icebergs, were some which came to my notice When, in company with the late Professor H. Carvill Lewis, I was tracing the glacial boundary across the State of Pennsylvania. We had reached the elevated plateau (two thousand feet above the sea) which extends westwards and southwards from the peak of Pocono Mountain, in Monroe County. This plateau consists of level strata of sandstone, the southern part of which is characterised by a thin sandy soil, such as is naturally formed by the disintegration of the under- lying rock, and there is no foreign material to be found in it. But, on going northwards to the boundary of Toby- hanna township, we at once struck a large line of accumu- lations, stretching from east to west, and rising to a height of seventy or eighty feet. This was chiefly an accumula- tion of transported boulders, resembling in its structure the terminal moraines which are found at the front of glaciers in the Alps and in Alaska, and indeed wherever active glaciers still remain. But here we were upon the summit of the mountain, where there are no higher levels to the north of us, down which the ice could flow. Be- 62 MAN AND THE GLACIAL PERIOD. sides, among these boulders we readily recognised many of granite, which must have come either from the Adiron- dack Mountains, two hundred miles to the north, or from the Canadian highlands, still farther away. Limiting our observations simply to the boulders, we should indeed have been at liberty to suppose that they had been transported across the valley of the Mohawk or of the Great Lakes by floating ice during a period of sub- mergence. But we were forbidden to resort to this hy- pothesis by the abrupt marginal line, running east and west, upon Pocono plateau, along which these northern boulders ceased. South of this evident terminal moraine there was no barrier, and there were no northern boulders. On the theory of submergence, there was no reason for the boundary-line so clearly manifested. Ice which had floated so far would have floated farther. Still further, on going a few miles east of the Pocono plateau, one descends into a parallel valley, lying between Pocono Mountain and Blue Mountain, and one thousand feet below their level. But our marginal southern bound- ary of transported granite rocks did not extend much farther south in the valley than it did on the plateau, except where we could trace the action of a running stream, evidently corresponding to the subglacial rivers which pour forth from the front of every extensive glacier. In these facts, therefore, we had a crucial test of the glacial hypothesis, and, in view of them, could maintain, against all objectors, the theory of the distant glacial transportation of boulders, even over vast areas of the North American continent. Since that experience, I have traced this limit of southern boulders for thousands of miles across the con- tinent, according to the delineation which may be seen in the map in a later chapter. If necessary, I could indi- cate hundreds of places where the proof of glacial trans- portation is alniost as clear as that on the Pocono plateau SIGNS OP PAST GLACIATION. 63 in Pennsylvania. One of the most interesting of these is on the hills in Kentucky, about twelve miles south of the Ohio River, at Cincinnati, where I discovered boulders of a conglomerate containing many pebbles of red jasper, which can be identified as from a limited formation crop- FlG. 25. — Conglomerate boulder found in Boone County, Kentucky. (See text. J ping out in Canada, to the north of Lake Huron, six hundred or seven hundred miles distant. That this was transported by glacial ice, and not by floating ice, is evi- dent from the fact that here, too, there was no barrier to the south, requiring deposits to cease at that point, and from the further fact that boulders of this material are found in increasing frequency all the way from Kentucky to the parent ledges in Canada. With reference to these boulders, as with reference to those found on the summit of Mount Washington, we can reason, also, that any northerly subsidence permitting a body of water to occupy the space between Kentucky and Lake Superior, and deep 64 MAN AND THIS GLACIAL PERIOD. enough to facilitate the movement across it of floating ice, would render it impossible for the ice to have loaded itself with them. The same line of reasoning is conclusive respecting the innumerable boulders which cover the northern portion of Ohio, where I have my residence. The whole State of Ohio, and indeed almost the entire Mississippi basin be- tween the Appalachian and the Rocky Mountains, is com- pletely covered, and to a great depth, with stratified rocks which have been but slightly disturbed in the elevation of the continent-; yet, down to an irregular border-line run- ning east and west, granitic boulders everywhere occur in great numbers. In the locality spoken of in northern Ohio the elevation of the country is from two hundred to five hundred feet above the level of Lake Erie. ,The near- est outcrops of granitic rock occur about four hundred miles to the north, in Canada. After the meeting of the Ameri- can Association for the Advancement of Science in To- ronto in the summer of 1889, I had the privilege of join- ing a company of geologists in an excursion, conducted by members of the Canadian Survey, to visit the region beyond Lake Nipissing, north of Lake Huron, where the ancient Laurentian and Huronian rocks are most typically developed. I took advantage of the trip to collect speci- mens of a great variety of the granites and gneisses and metamorphic schists and trap-rock of the region. On bringing them home I turned them over to the professor of geology, who at once set his class at work to see if they could match my fragments from Canada with correspond- ing fragments from the boulders of the vicinity. To the great gratification, both of the pupils and myself, they were able to do so in almost every case ; and so they might have done in any county or township to the south until reaching the limit of glacier action which I had previously mapped. Here, at Oberlin, on the north side of the water- shed, it is possible to imagine that we are on the southern SIGNS OP PAST GLACIATION. 65 border of an ancient lake upon whose bosom floating ice had brought these objects from their distant home in Canada. But this theory would not apply to the portion of the State which is south of the water-shed and which slopes rapidly towards the Gulf of Mexico, Yet the dis- tribution of boulders is practically uniform over the gla- ciated area on both sides of the water-shed, constituting thus an indisputable proof of the glacial theory. 4th. As the significance of the gravel terraces which mark the lines of outward drainage from the glaciated area cannot well be indicated in a single paragraph, the reader is referred for further information upon this point to the general statements respecting them throughout the next chapter. CHAPTEK V. ANCIENT GLACIERS IN THE WESTERN HEMISPHERE. New England. In North America all the indubitable signs of glacial action are found over the entire area of New England, the southern coast being bordered by a double line of terminal moraines. The outermost of these appears in Nantucket, Martha's Vineyard, No Man's Land, Block Island, and through the entire length of Long Island — from Montauk Point, through the centre of the island, to Brooklyn, N. Y., and thence across Staten Island to Perth Amboy in New Jersey. The interior line is nearly parallel with the outer, and, beginning at the east end of Cape Cod, runs in a westerly direction to Falmouth, and thence south- westerly through "Wood's Holl, and the Elizabeth Islands — these being, indeed, but the unsubmerged portions of the moraine. On the mainland this interior line reap- pears near Point Judith, on the south shore of Ehode Island, and, running slightly south of west, serves to give character to the scenery at Watch Hill, and thence crops out in the Sound as Fisher and Plum Islands, and farther west forms the northern shore of Long Island to Port Jef- ferson. In these accumulations bordering the southern shore of New England, the characteristic marks of glacial action can readily be detected even by the casual observer, and prolonged examination will amply confirm the first im- pression. The material of which they are composed is, ANCIENT GLACIERS. 67 for the most part, foreign to the localities, and can be traced to outcrops of rock at the north. The boulders scattered over the surface of Long Island, for example, consist largely of granite, gneiss, hornblende, mica slate, and red sandstone, which are easily recognised as frag- ments from well-known quarries in Connecticut, Ehode Island, and Massachusetts; yet they have been transported bodily across Long Island Sound, and deposited in a het- erogeneous mass through the entire length of the island. l^ot only do they lie upon the surface, but, in digging into the lines of hills which constitute the backbone of Long Island, these transported boulders are found often to make up a large part of the accumulation. Almost any of the railroad excavations in the city of Brooklyn present an interesting object-lesson respecting the composition of a terminal moraine. All these things are true also of the lines of moraine farther east, as just described. Professor Shaler has traced to its source a belt of boulders occurring extensively over southern Ehode Island, and found that they have spread out pretty evenly over a triangular area to the southward, in accordance with the natural course to be pursued by an ice-movement. Nearly all of Plymouth County, in south- eastern Massachusetts, is composed of foreign material, much of which can be traced to the hills and mountains to the north. Even Plymouth Eock is a boulder from the direction of Boston, and the " rock-bound " shores upon which the Pilgrims are poetically conceived to have land- ed are known, in scientific prose, as piles of glacial rub- bish dumped into the edge of the sea by the great conti- nental ice- sheet. The whole area of southeastern Massachusetts is dot- ted with conical knolls of sand, gravel, and boulders, sepa- rated by circular masses of peat or ponds of water, whose origin and arrangement can be accounted for only by the peculiar agency of a decaying ice-front. Indeed, this 68 MAN AND THE GLACIAL PERIOD. whole line of moraines, from the end of Cape Cod to Brooklyn, N. Y., consists of a reticulated network of ridges and knolls, so deposited by the ice as to form in- numerable kettle-holes which are filled with water where other conditions are favourable. Those which are dry are so because of their elevation above the general level, and of the looseness of the surrounding soil ; while many have been filled with a growth of peat, so that their original character as lakelets is disguised. As already described, these depressions, so characteris- tic of the glaciated region, are, in the majority of cases, supposed to have originated by the deposition of a great quantity of earthy material around and upon the masses of ice belonging to the receding front of the glacier, so that, when at length the ice melted away, a permanent de- pression in the soil was left, without any outlet. To some extent, however, the kettle-holes may have been formed by the irregular deposition of streams of wa- ter whose courses have crossed each other, or where eddies of considerable force have been produced in any way. The ordinary formation of kettle-holes can be observed in prog- ress on the fdot of almost any glacier, or, indeed, on a small scale, during the melting away of almost any winter's snow. Where, from any cause, a stratum of dirt has accumulated upon a mass of compact snow or ice, it will be found to settle down in an irregular manner ; furrows will be formed in various directions by currents of water, so that the melt- ing will proceed irregularly, and produce upon a miniature scale exactly what I have seen on a large scale over whole square miles of the decaying foot of the great Muir Glacier in Alaska. The effects of similar causes and conditions we can see on a most enormous scale in the ten thousand lakes and ponds and peat-bogs of the whole glaciated area both in North America and in Europe. In addition to these two lines of evidence of glacial action in New England, we should mention also the in- Copyright, 1889, by D. Appleton and Compaht. ANCIENT GLACIERS. 69 numerable glacial grooves and scratches upon the rocks which can be found on almost any freshly uncovered sur- face. In New England the direction of these grooves is ordinarily a little east of south. Upon the east coast of Massachusetts and New Hampshire the scratches trend much more to the east than they do over most of the in- terior. This is as it should be on the glacial theory, since the ice would naturally move outwards in the line of least resistance, which would, of course, be towards the open sea wherever that is near. In the interior of New England the scratches upon the rocks indicate a more southerly movement in the Connecticut Valley than upon the mountains in the western part of Massachusetts. This also is as it should be upon the glacial theory. The scratches upon the mountains were made when the ice was at its greatest depth and when it moved over the country in comparative disregard of minor irregularities of surface, while in the valleys, at least in the later por- tion of the Ice age, the movement would be obstructed except in one direction. In the interpretation of the glacial grooves and scratches it should be borne in mind that they often represent the work done during the clos- ing stages of the period. Just as the last shove of the carpenter's plane removes the marks of the previous work, so the last rasping of a glacial movement wears away the surfaces which have been previously polished and striated. In various places of New England it is interesting as well as instructive to trace the direction of the ice-move- ment by the distribution of boulders. My own atten- tion was early attracted to numerous fragments of gneiss in eastern Massachusetts containing beautiful crystals of feldspar, which proved to be peculiar to the region of Lake Winnepesaukee, a hundred miles to the north, and to a narrow belt stretching thence to the southwestward. In ascending almost any of the lower summits of the 70 MAN AND THE GLACIAL PERIOD. White Mountains one's attention can scarcely fail of be- ing directed to the difference between the material of which the mountains are composed and that of the nu- merous boulders which lie scattered over the surface. The local geologist readily recognises these boulders as pilgrims that have wandered far from their homes to the northward. Trains of boulders, such as those already described in Ehode Island, can frequently be traced to some prominent outcrop of the rock in a hill or mountain-peak from which they have been derived. One of the earliest of these to attract attention occurs in the towns of Richmond, Lenox, and Stockbridge, in the western part of Massachusetts. Here a belt of peculiar boulders about four hundred feet wide is found to originate in the town of Lebanon, N. Y., and to run continuously to the southeast for a distance of nine miles. West of Fry's Hill, where the outcrop occurs, no boulders of this variety of rock are to be found, while to the southeast the boulders gradually diminish in size as their distance from the outcrop increases. Near the out- crop boulders of thirty feet in diameter occur, while nine miles away two feet is the largest diameter observed. Sir Charles Lyell endeavoured to explain this train of boulders by the action of icebergs during a period of sub- mergence — supposing that, as icebergs floated past or away from this hill in Lebanon, N. Y., they were the means of the regular distribution described. It is need- less to repeat the difficulties arising in connection with such a theory, since now both by observation and experi- ment we have become more familiar with the movement of glacial ice. What we have already said about the trans- portation of boulders over Switzerland by the Alpine glaciers, and what is open to observation at the present time upon the large glaciers of Alaska, closely agree with the facts concerning this Eichmond train of boulders, and we have no occasion to look further for a cause. ANCIENT GLACIERS 71 Indeed, trains of boulders ought to appear almost everywhere over the glaciated area ; and so they do where all the circumstances are favourable. But, readily to iden- tify the train, requires that to furnish the boulders there should be in the line of the ice-movement a projecting mass of rock hard enough to offer considerable resistance to the abrading agency of the ice and characteristic enough in its composition to be readily recognised. Ship Kock, in Peabody, Mass., weighing about eleven hundred tons, and Mohegan Rock, in Montville, Conn., weighing about ten thousand tons, have ordinarily been pointed to as boulders illustrating the power of ice-action. Their glacial character, however, has been challenged from the fact that the variety of granite to which they belong occurs in the neighbourhood, and indeed constitutes the bed-rock upon which they rest.* Some would therefore consider them, like some of which we have already spoken, to be boulders which have originated through the disintegration of great masses of rock, of which these were harder nuclei that have longer resisted the ravages of the tooth of time. It must be admitted that possibly this explanation is correct ; but it is scarcely probable that, in a region where there are so many other evidences of glacial action, these boul- ders could have remained immovable in presence of the onward progress of the ice-current that certainly passed over them. However, as already seen, we are not left to doubt as to the movement of some boulders of great size. That which now claims the reputation of being the largest in New England is in Madison, N. H., and measures thirty by forty by seventy-five feet. This can be traced to ledges of Conway granite, about two miles away.f Many boulders in the vicinity of New Haven, Conn., can be * Popular Science Monthly, vol. xxxvii, pp. 196-201. f See W. 0. Crosby's paper in Appalaohia, vol. vi, pp. 59-70. 72 MAN AND THE GLACIAL PERIOD. identified, as from well-known trap-dykes, sixteen miles or more to the north. The so-called Judge's Cave, on West Kock, 365 feet above the adjoining valley and weighing a thousand tons, is one of these. Professor Ed- fiu. at).- McihcHiui Kcick. ward Orton * describes a mass of Clinton limestone near Fi-eej^ort, Warren County, Ohio, as covering an area of three-fourths of an acre, and as sixteen feet in tliickness. It overlies glacial clays and gravels, and must have been transported bodily from the elevations containing this rock several miles to the northwest. * Geological Survey of Ohio, vol. iii, p. 385. AKCIBNT GLACIERS. 73 Portions of New England present the best illustrar tions anywhere afforded in America of what are called " drumlins." These are " lenticular-shaped " hills, com- posed of till, and containing, interspersed through their mass, numerous scratched stones of all sizes. They vary in length from a few hundred feet to a mile, and are usu- ally from half to two-thirds as wide as they are long. In height they vary from twenty-five to two hundred feet. But, according to the description of Mr. Upham, what- ever may be their size and height, they are singularly alike in outline and form, usually having steep sides, with gently sloping, rounded tops, and presenting a very smooth and regular contour. From this resemblance in shape to an elliptical convex lens, Professor Hitchcock has called them lenticular hills to distinguish these de- posits of till from the broadly flattened or undulating sheets which are common throughout New England. Fig. 27.— Drumlins in Gofletown, N. H. (Hitchcock). The trend, or direction of the longer axis, of these lenticular hills is nearly the same for all of them com- prised within any limited area, and is approximately like the course of the striae or glacial furrows marked upon the neighbouring ledges. In eastern Massachusetts and 74 MAN AND THE GLACIAL PERIOD. 'Sew ilampshire, within twenty-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 Eiver 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, show- ing a considerable deflection towards the southeast and northwest in the east part of the State. It cannot 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 stri^ with which they are parallel.* Drumlins are abundant in the vicinity of Boston, and constitute nearly all the islands in Boston Harbour. On the mainland, Beacon Hill, Bunker Hill, Green Hill, Pow- derhorn Hill, Tufts College Hill, Winter Hill, Mount Ida, Corey Hill, Parker Hill, Wollaston Heights, Prospect Hill, and Telegraph Hill are specimens. The northeastern corner of Massachusetts and the southeastern corner of New Hampshire are largely cov- ered with these peculiar-shaped glacial deposits, while they are numerous as far west as Fitchburg, in Massachu- setts, and Ware, N. H., and in the northeastei-n part of Connecticut. A little later, also, we shall refer to an in- teresting line of them in central New York. Elsewhere in America, except in a portion of Wisconsin, they rarely occur in such fine development as in New England. In Europe they are best developed in portions of Ireland. One's first impression in examining an exposed section * Proceedings of the Boston Society of Natural History, vol. xx, pp. 334, 335. ANCIENT GLACIERS. Y5 of a drumlin would lead him to think that the mass was entirely unstratified ; but closer examination shows that Pig. 38. — Drumlins in the vicinity of Boston (Davis). there is a coarse stratification, but evidently not produced by water-action. The accumulation has probably taken place gradually by successive deposits underneath the glacier itself. Professor William M. Davis has suggested a plausible explanation which we will briefly state. The frequency with which drumlins are found to rest upon a mass of projecting rock, the general co-ordination of the direction of their axes with the direction of the scratches upon the underlying rock, and the abundance of scratched stones in them, all support the theory that drumlins are formed underneath the ice-sheet, somewhat in the way that islands and bars of silt are formed in the delta of a great river. The movement of ice seems to 76 MAN AND THE GLACIAL PERIOD. have been concentrated in pretty definite lines, often de- termined by the contour of the bottom, leaving a slacker movement in intervening areas, which were evidently pro- tected in some cases by projecting masses of rock. In these areas of slower movement there was naturally an accumulation at the same time that there was vigorous erosion in the lines of more rapid movement. There was doubtless a continual transfer of material from the end of the drumlin which abutted against the moving mass of ice to the lower end, as there is in the formation of an island in a river. If time enough had elapsed, the whole accumulation would have been levelled by the glacier and spread over the broader area where the more rapid lines of movement became confluent, and where the differential motion was less marked. Drumlins are thus characteristic of areas in the glaciated region whose floor was originally only moderately irregular, and where there was an excessive amount of ground moraine to be transported, and where the movejnent did not con- tinue indefinitely. It has been suggested, also, that some of the long belts of territory in New England and central New York covered by drumlins may represent old terminal moraines which were subsequently surmounted by a re- advance of the ice, and partially wrought over into their present shape. It is in New England, also, that kames are to be found in better development than anywhere else in America. These interesting remnants of the Glacial age are clearly described by Mr. James Geikie. His account will serve as well for New England as for Scotland. The sands and gravels have a tendency to shape them- selves into mounds and winding ridges, which give a hummocky and rapidly undulating outline to the ground. Indeed, so characteristic 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 ANCIENT GLACIERS. 77 vegetation and soil stripped away and the various subsoils laid bare. Occasionally, ridges may be tracked continu- ously for several miles, running like great artificial ram- parts across the country. These vary in breadth and 1 N N N N.W. Pig. 29. — Section of karae near Dover, New Hampshire. Length, three hundred feet ; height, forty feet ; base, about forty feet above the Cocheco River, or Beventy-flve feet above the sea. a, a, gray clay; b, fine sand; c, c, coarse gravel containing pebbles from six inches to one foot and a half in diameter; a, d, fine gravel (Upham). 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 de- grees, 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 confusedly intermingled, crossing and recrossing each other at all angles, so as to enclose 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 beautiful peaks and cones, and anon curving up in sharp ridges that often wheel suddenly round so as to enclose a lakelet of bright clear water.* In New England attention was first directed to kames in 1843, by President Edward Hitchcock, in a paper be- fore the American Association of Geologists and Natural- ists, describing the gravel ridges in Andover, Mass. In the accompanying plate is shown a portion of this kame system, which has a double interest to me from the fact that it was while living upon the banks of the Shawshin * The Great Ice Age, pp. 210, 311. 78 MAN AND THE GLACIAL PERIOD. Eiver, near where the kames and the river intersect, that I began, in 1874, my special study of glacial deposits. The KAMES ITT ANDOVER -„? ^v Fig. 30. Andover ridges are composed of imperfectly stratified water-worn material, and are very sharply defined, from 80 MAN AND THE GLACIAL PERIOD, the town of Chelsea, back from the coast into New Hamp- shire, for a distance of twenty-flve miles. The base of the ridges does not maintain a uniform level, but the system descends into shallow valleys, and rises over elevations of one hundred to two hundred feet, without interruption. This indifference to slight changes of level is specially noticeable where the system crosses the Merrimac River, just above the city of Lawrence. It is also represented in the accompanying plate, where the base of the ridges in the immediate valley of the Shawshin is fifty feet lower than the base of those a short distance to the north, at the points marked a, i, and c. The ridges here terminate at the surface in a sharp angle, and are above their base forty-one feet at a, forty-nine feet at b, and ninety-one feet at c. Between c and b there is an extensive peat-swamp, filling the depression up to the level of an outlet through which the surplus water has found a passage. Several systems of kames approximately parallel to this have been traced out in Massachusetts and New Hampshire, while the remnants of a very extensive sys- tem are found in the Connecticut Valley above the Mas- sachusetts line. But they abound in greatest profusion in the State of Maine, where Professor G-eorge H. Stone has plotted them with much care. The accompanying map gives only an imperfect representation of the ramify- ing systems which he has traced out, and of the extent to which they are independent of the present river- channels. One of the longest of these extends more than one hun- dred miles, crossing the Penobscot River nearly opposite Grand Lake, and terminating in an extensive delta of gravel and sand in Cherryfield, nearly north of Mount Desert. This is represented on our map by the shaded portion west of the Machias River. Locally these ridges are variously designated as " horsebacks," " hogbacks," or " whalebacks," but that in Andover, Mass., was for some reason called " Indian Ridge." Nowhere else in the world ANCIENT GLACIERS. 81 are these ridges better deyeloped than in New England, except it be in southern Sweden, where they have long been known and carefully mapped. SCALE OF MfLES 3trut/ier» j Oi., Engr'a, N. Y. Fio. 38.— The kames of Maineand Boutheastern New Hampshire. (Stone.) The investigations of Mr. W. 0. Crosby upon the com- position of till in eastern Massachusetts is sufficiently im- 82 MAN AND THE GLACIAL PERIOD. portant in its bearings upon the question of glacial erosion to merit notice at this point.* The object of his investi- gations was to determine how much of the so-called ground moraine, or till, consisted of material disintegrated by mechanical action, and how much by chemical action. The " residuary clay," which has arisen from chemical de- composition, would properly be attributed to the disinte- grating agencies of preglacial times, while the clay, which is strictly mechanical in its origin, remains to represent the true " grist " or " rock flour " of the Glacial period. The results of Mr. Crosby's investigations show that " not more than one-third of the detritus composing the till of the Boston Basin was in existence before the Ice age, and that the remaining two- thirds must be attributed to the mechanical action of the ice-sheet and its accom- panying torrents of water. In other words, if we assume the average thickness of the drift as thirty feet, the amount of glacial erosion can scarcely fall below twenty feet. After scraping away the residuary clays and half- decomposed material, the ice-sheet has cut more than an equal depth into the solid rocks." Mr. Crosby's investigations also convinced him that the movement of the till, or ground moraine, underneath the ice was not en masse, but that " it must have experienced dif- ferential horizontal movements or flowing, in which, nor- mally, every particle or fragment slipped or was squeezed forward with reference to those immediately below it, the velocity diminishing downward through the friction of the underlying ledges. . . . The glaciation was not limited to masses which were firmly caught between the ice and the solid ledges, and it was in every case essentially a slip- ping and not a rolling movement. . . . These differential horizontal movements mean that the till acted as a lubri- * Proceedings of the Boston Society of Natural History, vol. XXV (1890), pp. 115-140. ANCIENT GLACIERS. 83 dant for the ice-sheet ; and the clayey element, especially, co-operating in many cases with the pent-up subglacial waters, must have greatly facilitated the onward progress of the ice." He concludes, therefore, that the onward movement of the vast ice-sheet greatly exceeded that of the main part of the ground moraine, the ice-sheet slipping over the till, the whole being in some degree analogous to that of a great land-slip. " In both cases the progress of a somewhat yielding and mobile mass is facilitated by an underlying clayey layer saturated with water." New Yorh, New Jersey, and Pennsylvania. West of New England the glacial phenomena over the northern part of the United States are equally marked all the way to the Missouri River, and the boundary-line of the glaciated region can be traced with little difficulty. It emerges from New York Bay on Staten Island and enters New Jersey at Perth Amboy. A well -formed moraine covers the northern part of Staten Island, and upon the mainland marks the boundary from Perth Amboy, around through Earitan, Plainfield, Chatham, Morris, and Hanover, to Eockaway, and thence in a southwesterly direction to Belvidere, on the Delaware Eiver. That portion of New Jersey lying north of this serpentine line of moraine hills is characterised by the presence of transported boulders, by numerous lakes of evident glacial origin, and by every other sign of glacial action, while south of it all these peculiar characteristics are absent. The observant passenger upon the railroad trains between New York and Philadelphia can easily recognise the moraine as it is passed through on the Pennsylvania Eailroad at Metuchen and on the Bound Brook Railroad at Plainfield. Near Drakestown, in Mor- ris County, there is a mass of blue limestone measuring, as exposed, thirty-six by thirty feet, and which was quar- ried for years before discovering that it was a boulder 84 MAN AND THE GLACIAL PERIOD. brought with other drift material from many miles to the northwest and lodged here a thousand feet above the sea. Across Pennsylvania the glacial boundary passes through Northampton, Monroe, Luzerne, Columbia, Sul- livan, Lycoming, Tioga, and Potter Counties, where it en- ters the State of N"ew York, running still in a northwest direction through Allegany and Cattaraugus Counties to the vicinity of Salamanca. Here it turns to the south nearly at a right angle, running southwestward to Chau- tauqua County and re-entering Pennsylvania in Warren County, and thence passing onward in the same general direction through Crawford, Venango, Mercer, Butler, and Lawrence Counties to the Ohio line in Columbiana County, about ten miles north of the Ohio Eiver. The occurrence of a well-defined terminal moraine to mark the glacial boundary eastward from Pennsylvania led Professor Lewis and myself, who made the survey of that State in 1880, to be rather too sanguine in our ex- pectations of finding an equally well-marked moraine everywhere along the southern margin of the glaciated area; still, the results are even more interesting than would have been the exact fulfilment of our expectations, since they more fully revealed to us the great complexity of efEect which is capable of being brought about by ice- action. Before proceeding farther with the details, there- fore, it will be profitable at this point to pause in the narrative and briefly record a few generalisations that have forced themselves into prominence during the years in which field-work has been in progress. Previous to our explorations in Pennsylvania it had been thought that the indications of ice-action would extend much farther south in the valleys than on the mountains, and this indeed would have been the case if the glaciers in northern Pennsylvania had been of local origin; but our experience very soon demonstrated that the great gathering-place of the snows which produced ANCIENT GLACIERS. 86 the glacial movement in northern Pennsylvania could not have been local, but that over the northern part of that State there was distinct evidence of a continental move- ment of ice whose centre was far beyond the AUegha- nies. For example, we found that the evidences of direct glacial action extended farther south upon the hills and plateaus than they did in the narrow valleys, while every- where on the very southern border of glacial indications we found boulders that had been brought from the gra- nitic region of northern New York or central Canada. In eastern Pennsylvania we found indeed a terminal mo- raine more or less distinctly marking the southern border over the highlands. This was more specially true in Northampton and Monroe Counties. In Northampton County it was very interesting to see long lines of hills, a hundred or more feet in height and lying several hundred feet above the Delaware Eiver, com- posed entirely of glacial debris, much of which had been brought bodily over the sharp summit of the Blu". Eidge, or Kittatinny Mountain, which rises as a continuous wall to the northwest and is everywhere several hundred feet higher than the moraine in Northampton County. The summit of Blue Eidge, also, as far south as the glacial movement extended, shows evident signs of glacial abra- sion, some hundreds of feet evidently having been removed by that means, leaving a well-defined shoulder, marking the limits of its southwestern border. Eesting upon the summit of the glaciated portion of the Blue Eidge, there are also numerous boulders of Helderberg limestone, which must have been brought from ledges at least five hundred feet lower than the places upon which they now lie. In Monroe County the terminal moraine marking there the extreme limit of the ice-movement is upon an exten- sive plateau of Pocono sandstone, about eighteen hundred feet above sea-level, and five or six hundred feet lower than 86 MAN AND THE GLACIAL PERIOD. the crest of the Alleghany Mountains, a short distance to the north. The moraine hills are here well marked by the occurrence of circular lakelets and kettle-holes (such as have been described as characteristic of the shores and islands bordering the south of New England) ; by the occurrence of granitic boulders, which must have been brought from the Adirondacks or Canada; and by the various other indications referred to on a previous page. As already intimated, the instructive point in our ob- servations is the fact that, between Kittatinny Mountain, in Northampton County, and Pocono plateau, in Monroe County, there is a longitudinal depression, running north- east by southwest, parallel with the ranges of the moun- tain system, which is here about a thousand feet below the respective ridges on either side. This, therefore, is one of the places where we should have expected a considerable southern extension of the ice, if it had been largely due to local causes. Now, while there is indeed a gradual south- ern trend down the flanks of the mountain, yet, upon reach- ing the axis of the valley, there appears at once a very marked change in the character of the deposit, and the influence of powerful streams of water becomes manifest, and it is evident, upon a slight inspection, that we have come upon a line of drainage which sustained a peculiar relation to the continental ice-sheet. From Stroudsburg, near the Delaware Water- Gap, to Weissport, on the Lehigh Eiver, a distance of about thirty miles, the valley between the mountains is continuous, and the elevation at each end very nearly the same. But about half-way between the two places, near Saylorsburg, there is a river-parting from which the water now runs on the one hand north to Stroudsburg, and thence to the Dela- ware Kiver, and on the other hand south, through Big and Aquonchichola Creeks, to the Lehigh Eiver. The river- pArting is formed by a great accumulation of gravel, whose summit is about two hundred feet above the level of the ANCIENT GLACIERS. 8Y valleys into which the creeks empty at either end; and there are numerous kettle-holes and lakelets in the vicini- ty, such as characterize the glacial region in general. In short, we are, without doubt, here on a well-marked terminal moraine much modified by strong water-action in a valley of glacial drainage. The gravel and boulders are all well water-worn, and the material is of various kinds, including granite boulders from the far north, such as char- acterise the terminal moraine on the highlands ; but the pebbles are not scratched, and the gravel is more or less stratified. It is evident that we are here where a violent stream of water poured forth from that portion of the ice- front which filled this valley, and which found its only out- let in the direction of the Lehigh Eiver. The gravel can be traced in diminishing quantities to the southward, in accordance with this theory, while to the northward there extends a series of gravel ridges, or kames, such as we have shown naturally to owe their origin to the accumulations taking place in ice-channels formed near the front of a glacier as it slowly melts away. From similar occurrences of vast gravel accumulations in other valleys stretching southward from the glacial margin, we came to expect that, wherever there was an open line of drainage from the glaciated region south- ward, the point of intersection between the glacial margin and the drainage valley would be marked by an excessive accumulation of water- worn gravel, diminishing in coarse- ness and abundance down the valleys in proportion to the distance from the glacial margin. For example, the Delaware Kiver emerges from the glaciated region at Belvidere, and there are there vast ac- cumulations of gravel rising a hundred or more feet above the present level of the river, while gravel terraces, dimin- ishing in height, mark the river below to tide-water at Trenton. The Lehigh River leaves the glaciated region at Hickory Run, a few miles above Mauch Chunk, but 88 MAN AND THE GLACIAL PERIOD. the gorge is so steep that there was little opportunity either for the accumulatioii of grayel there or for its preser- vation. Still, the transported gravel and boulders charac- teristic of the melting floods pouring forth from a glacier, are found lining the banks of the Lehigh all along the lower portion of its course. In the Susquehanna Eiver we have a better example at Beach Haven, in Luzerne County, where there are very extensive accumulations of gravel resting on the true glacial deposits of the valley, and extending down the river in terraces of regularly diminishing height for many miles, and merging into ter- races of moderate elevation which line the Susquehanna Valley throughout the rest of its course. Above Beach Haven the gravel deposits in the trough of the river valley are more irregular, and betray the modifying influence of the slowly decaying masses of ice which belonged to the enveloping continental glacier. Westward from the north fork of the Susquehanna, similar extensive accumulations of gravel occur at the in- tersection of Fishing Creek in Columbia County, Muncy, Loyalsock, Lycoming, and Pine Creeks in Lycoming County, all tributary to the Susquehanna Eiver, and all evidently being channels through which the melting floods of the ice-sheet brought vast quantities of gravel down to the main stream. Williamsport, on the West Branch of the Susquehanna, is built upon an extensive terrace con- taining much granitic material, brought down from the glaciated region by Lycoming Creek, when it was flooded with the waters melted from the continental ice-sheet which had here surmounted the AUeghanies and invaded the valley of the Susquehanna. Analogous deposits of unusual amounts of gravel, oc- curring in streams flowing southward from the glaciated region, occur at Great Valley, Little Valley, and Steam- burg in Cattaraugus County, Few York, and at Eussel- burg and Garland in Warren County, Pennsylvania, also ANCIENT GLACIERS. 89 at Titusville and Franklin in Venango County, and at Wampum in Lawrence County, of the same State. As a rule, Professor Lewis and myself found it more difficult to determine with accuracy the exact point to which the ice extended in the axis of these south-flowing valleys than we did upon the highlands upon either side ; and, in looking for the positive indications of direct ice- action in these lines of drainage, we were almost always led up the valley to a considerable distance inside of the line. This arose from our inexperience in interpreting the phenomena, or rather from our inattention to the well-known determining facts in the problem. On fur- ther reflection it readily appeared that this was as it should be. The ice-front, instead of extending farther down in a narrow valley than on the adjoining highlands (where they are of only moderate elevation) ought not to extend so far, for the subglacial streams would not only wear away the ice of themselves, but would admit the air into the tunnels formed by them so as to melt the masses both from below and from above, and thus cause a recession of the front. If we had understood this principle at the be- ginning of our survey, it would have saved us much per- plexity and trouble. A single further illustration of this point will help to an understanding of many references which will hereafter be made to the water deposits which accumulated in the lines of drainage running southward from the glaciated area. At Warren, Pa., Conewango Creek, which is the outlet from Chautauqua Lake, enters the Alleghany River after flowing for a number of miles in a deep valley with moderate slopes. In ascending the creek from Warren, the gravel terraces, which rise twenty-five or thirty feet above high -water mark, rapidly increase in breadth and height, and the pebbles become more and more coarse. After a certain distance the regular terraces begin to give place to irregular accumulations of gravel in ridges and 90 MAN AND THE GLACIAL PERIOD. knobs. In the lower portion of the valley no pebbles could be found which were scratched. Up the valley a few miles pebbles were occasionally discovered which showed some slight indications of having been scratched, but which had been subjected to such an amount of abra- sion by water-action as almost to erase the scratches. On reaching Ackley's Station, the stream is found to be cut- ting through a regular terminal moraine, extending across the valley and full of clearly marked glaciated stones. Above this terminal moraine the terraces and gravel ridges which had characterised the valley below disappear, giving place to long stretches of level and swampy land, which had been subject to overflow. Something similar to this so often appears, that there can be no question as to its meaning, which is, that dur- ing the farthest extent of the ice the front rested for a considerable period of time along the line marked by the terminal moraine. During this period there occurred both the accumulation of the moraine and of the gravel terraces in the valley below, due to the vast flow of water emerg- ing from the ice-front, especially during the period when it was most rapidly melting away. Upon the retreat of the ice, the moraine constituted a dam which has not yet been wholly worn away. For a while the water was so ef- fectually ponded back by this as to form a lake, which has since become flUed up with sediment and accumulations of peat. From this it is evident, also, that when the ice began to retreat, the retreat was so continuous and rapid that no parallel terminal moraines were formed for many miles. Before leaving this section we will summarise the leading facts concerning the glacial phenomena north of Pennsylvania and New Jersey. From the observations of Professor Smock, it appears that, from the southern mar- gin the ascent to the summit of the ice-sheet was pretty rapid ; the depth one mile back from the margin being ANCIENT GLACIERS. 91 not much less than a thousand feet. "Northv/ard the angle of the slope diminished, and the glacier surface ap- proximated to a great level plain. The distance between the high southwestern peaks of the Oatskills and Pocono Knob in Pennsylvania is sixty miles. The difference in the elevation of the glacier could not have exceeded a thousand feet," * that is, the slope of the surface was about seventeen feet to the mile. Professor Dana estimates the thickness of the ice in southern Connecticut to have been between fifteen hun- dred and two thousand feet. Attempts to calculate the thickness of the ice farther north, except from actual dis- covery of glacial action on the summits of the mountains, are based upon uncertain data with reference to the slope necessary to secure glacial movement. In the Alps the lowest mean slopes down which glaciers move are about two hundred and fifty feet to a mile ; but in Greenland, Jensen found the slope of the Frederickshaab Glacier to be only seventy-five feet to the mile, while Helland found that of the Jakobshavn Glacier to be only forty-five feet. It is doubtful if even that amount is necessary to se- cure a continental movement of ice, since, as already re- marked, it is unsafe to draw inferences concerning the movements of large masses of ice from those of smaller masses in more constricted areas. We have seen, from the glacial deposits on the top of Mount Washington, that over the northern part of New England the ice was more than a mile in depth. We have no direct evidence of the depth of the stream which surrounded the Adiron- dack Mountains. Nor, on the other hand, are we certain that the Catskills were not completely enveloped in ice, though most observers, reasoning from negative evidence, have supposed that to be the case. But from the facts stated concerning the boulders along the glacial boundary * American Journal of Science, vol. cxxv, 1883, p. 339 et seq. 92 MAN AND THE GLACIAL PERIOD. in Pennsylvania, it is certain that the ice was deep enough to surmount the ridge of the Alleghanies where they are two thousand and more feet in height. At the least cal- culation the ice must have been five hundred feet thick, in order to secure the movement of which there is evi- dence across the Appalachian range. Supposing this to be the height of the ice above the sea on the crest of the Alleghanies, and that the slope of the surface of the ice- sheet was as moderate as Professor Smock has estimated it (namely seventeen feet to the mile), the ice would be upwards of six thousand feet in thickness in the latitude of the Adirondacks, which corresponds closely with the positive evidence we have from the mountains in New England. A study of the map of New York will make it easy to understand the distribution of some interesting glacial marks over the State. The distance along the Hudson from the glacial boundary in the vicinity of New York to the valley of the Mohawk is about one hundred and sixty miles. From the glacial boundary at Salamanca, N. Y., to the same valley, is not over eighty miles. It is easy to see, therefore, that when, in advancing, the ice moved southward past the Adirondacks, the east end of the valley of the Mohawk was reached and closed by the ice, while at the west end of Lake Ontario the ice-front was still in Canada. Thus the drainage, which naturally followed the course of the St. Lawrence, would first be turned through the Mohawk. Afterwards, when the Mohawk had been closed by ice, the vast amount of ponded water was compelled to seek a temporary outlet over the lower passages leading into the Susquehanna or into the Alle- ghany. A number of such passages exist. One can be traced along the line of the old canal from TJtica to Bingham- ton, whose highest level is not far from eleven hundred feet. Another lies in a valley lea.^ing south of Cayuga ANCIENT GLACIERS. 93 Lake, whose highest point, at Wilseyville, is nine hundred and forty feet above tide. Another leads south to the Chemung River from Seneca Lake, whose highest point, at Horseheads, is less than nine hundred feet above tide. The cols farther west are somewhat more elevated ; the one at Portage, leading from the Genesee Eiver into the Canisteo, being upwards of thirteen hundred feet, and that of Dayton, leading from Cattaraugus. Creek into the Conewango, being about the same. Of other southern outlets farther west we will speak later on. Fixing our minds now upon the region under consid- eration, in the southern part of the State of New York, we can readily see that a glacial lake must have existed in front of the ice while it was advancing, until it had reached the river-partings between the Mohawk and the St. Law- rence Rivers on the north and the Susquehanna and Alle- ghany Rivers on the south. After the ice had attained its maximum extension, and was in process of retreat, there would be a repetition of the phenomena, only they would occur in the reverse order. The glacial markings which we see are, of course, mainly those produced during the general retreat of the ice. The Susquehanna River stretching out its arms — the Chenango and Chemung Rivers — to the east and the west, evidently serves as a line of drainage for the vast glacial floods. These floods have left, along their courses, extensive elevated gravel terraces, with much material in them which is not local, but which has been washed out of the direct glacial deposits from the far north. The east-and-west line of the water-parting throughout the State is charac- terised by excessive accumulations of glaciated material, forming something like a terminal moraine, and is desig- nated by President Ohamberlin as " the terminal moraine of the second Glacial epoch," corresponding, as he thinks, to the interior line already described as characterising the south shore of New England. 94 MAN AND THE GLACIAL PERIOD. In the central part of New York the remarkable se- ries of " Finger Lakes," tributary to Lake Ontario and emptying into it through the Oswego and Genesee Rivers, all have a glacial origin. Probably, however, they are not due in any great degree to glacial erosion, but they seem to occupy north- and-south valleys which had been largely formed by streams running towards the St. Lawrence when there was, by some means (probably through the Mohawk Eiver), a much deeper outlet than now exists, but which has been filled up and obliterated by glacial debris. The ice-movement naturally centred itself more or less in these north-and-south valleys, and hence some- what enlarged them, but probably did not deepen them. The ice, however, did prevent them from becoming filled with sediment, and on its final retreat gave place to water. Between these lakes and Lake Ontario, also, and ex- tending east and west nearly all the way from Syracuse to Rochester, there is a remarkable series of hills, from one hundred to two or three hundred feet in height, composed of glacial debris. But while the range extends east and west, the axis of the individual hills lies nearly north and south. These are probably remnants of a morainic ac- cumulation which were made during a pause in the first advance of the ice, and were finally sculptured into their present shape by the onward movement of the ice. These are really " drumlins," similar to those already described in northeastern Massachusetts and southeastern New Hampshire. In the valley of central New York these have determined the lines of drainage of the " Finger Lakes," and formed dams across the natural outlets of nearly all of them. North of the State of New York the innumerable lakes in Canada are all of glacial origin, being mostly due to depressions of the nature of kettle-holes, or to the dam- ming up of old outlets by glacial deposits. A pretty well- ANCIENT GLACIERS. 95 marked line of moraine hills, formed probably as termi- nal deposits in the later stages of the Ice age, runs from near the eastern end of Lake Ontario to the Georgian Bay, passing south of Lake Simcoe. The Mississippi Basin. The physical geography of the glaciated region north of the Ohio Kiver is so much simpler than that of New England and the Middle States, that its characteristics can be briefly stated. Ohio, Indiana, and Illinois are cov- ered with nearly parallel strata of rock mostly of the Car- boniferous age. In general, the surface slopes gently to the west; the average elevation of Ohio being about a thousand feet above tide, while that of the Great Lakes to the north and of the middle portion of the Mississippi Valley is less than six hundred feet. The glacial deposits are spread in a pretty even sheet over the area which was reached by the ice in these States, and the lines of mo- raine, of which a dozen or more have been partially traced in receding order, are much less clearly marked than they are in New England, or in Michigan, and the States far- ther to the northwest. The line marking the southern limit attained by the ice of the Glacial period in these three States is as follows : Entering Ohio in Columbiana County, about ten miles north of the Ohio River, the glacial boundary runs west- ward through New Lisbon to Canton in Stark County, and thence to Millersburg in Holmes County. A few miles west of this place it turns abruptly south, passing through Danville in Knox County, Newark in Licking County, Lancaster in Fairfield County, to Adelphi in Eoss County. Thence bearing more westward it passes through Chillicothe to southeastern Highland County and north- western Adams, reaching the Ohio River near Eipley, in Clermont County. Thence, following the north bank of the Ohio River to Cincinnati, it crosses the river, and after 8 96 MAN AND THE GLACIAL PERIOD. extending through the northern part of Boone County, Kentucky, and recrossing the river to Indiana, not far from Eising Sun, it again follows approximately the north bank of the river to within about ten miles of Louisville, Ky., where it bends northward running through Clarke, Scott, Jackson, Bartholomew, and Brown Counties to Mar- tinsville, in Morgan County, where it turns again west and south and follows approximately the West Branch of the White Eiver through Owen, Greene, and Knox Counties, where it crosses the main stream of White Eiver, and, con- tinuing through Gibson and Posey Counties, crosses the Wabash Eiver near New Harmony. In Illinois the line still continues southwesterly through White, Gallatin, Saline, and Williamson Counties, where it reaches its southern limit near Carbondale, in latitude 37° 40', and from this point trends northwestward, ap- proximately following the northeastern bluff of the Mis- sissippi River, to the vicinity of Carondelet, 5Io., a short distance south of St. Louis. Beyond the Mississippi the line follows approximately the course of the Missouri Eiver across Missouri, and con- tinues westward to the vicinity of Manhattan, in Kansas, where it turns northward, keeping about a hundred miles west of the Missouri Eiver, through eastern Kansas and Nebraska, and striking the river near the mouth of the Niobrara, in South Dakota. From there the line follows approximately the course of the Missouri Eiver to the vicin- ity of Fort Benton, in northwestern Montana, where the line again bears more northward, running into British America. It is still in dispute whether the ice extended from the eastern centre far enough west to Join the ice-movement from the Eocky Mountain plateau. Dr. George M. Daw- son * is of the opinion that it did not, but that there was * Transactions of t}ie Royal Society of Canada, vol. viii, sec. iv, pp. 54^74. ANCIENT GLACIERS. 97 a belt of a hundred miles or more, east of the Eocky Moun- tains, which was never covered by true glacial ice. Mr, Upham * is equally confident that the two ice-movements became confluent, and united upon the western plateau of Manitoba. The opportunity for such a difference of opin- ion arises in the difficulty sometimes encountered of dis- tinguishing between a direct glacial deposit and a deposit taking place in water containing boulder-laden icebergs. Where Mr. Upham supposes the ice-fields of the east and of the west to have been confluent in western Manitoba, Dr. Dawson supposes there was an extensive subsidence of the land sufficient to admit the waters of the ocean. Leav- ing this question for the present undetermined, we will now rapidly summarise the glacial phenomena west of the third meridian from Washington (which corresponds near- ly with the western boundary of Pennsylvania), and east of the Eocky Mountains. That the glacial movement extended to the southern boundary just delineated is established by the presence down to that line of all the signs of glacial action, and their absence beyond. Glacial groovings are found upon the freshly uncovered rock surfaces at frequent intervals in close proximity to the line all along its course, while granitic boulders from the far north are scattered, with more or less regularity, over the whole intervening space between this line and the Canadian highlands. I have already referred to a boulder of jasper conglomerate found in Boone County, Kentucky, which must have come from unique outcroppings of this rock north of Lake Huron. Granitic boulders from the Lake Superior region are also found in great abundance at the extreme margin men- tioned in southern Illinois. West of the Missouri Eiver it is somewhat more difficult to delineate the boundary * American Geologist, vol. vi, September, 1890 ; Bulletin of the Geological Society of America, vol. ii, pp. 243-270. 98 MAN AND THE GLACIAL PERIOD. with accuracy, on account of an enveloping deposit of fine loam, technically called " loess." Loess is very abundant in the whole valley of the Missouri Eiver below Yankton, South Dakota, being for a long distance in the vicinity of the river a hundred feet or more in depth. Over north- ern Missouri and southern Illinois the deposit is nearly continuous, but less in depth, and everywhere in that re- gion tends to hide from view the ujistratified glacial de- posit continuously underlying it. A single instance of personal experience will illustrate the condition of things. While going south from Chicago, in search of the southern limit of glacial action, I stopped off from the train at Du Quoin, about forty miles north of where I subsequently found the boundary. Here the whole surface was covered with loess, two or three feet in depth. Below this was a gravelly soil, three or four feet in thickness, which contained many scratched pebbles of granite. A well which had recently been dug, reached the rock at a depth of twenty feet, and revealed a beauti- fully polished and scratched surface, betraying, beyond question, the action of glacial ice. As we shall show a little later, it is probable that, about the time the ice of the Glacial period had reached its maximum development, this area, which is covered with loess, was depressed in level, and remained under water during a considerable portion of the period when the ice-front was retreating. To such an extent is this portion of the area included in southern Iowa, northern Missouri, southern Illinois, and the extreme southern portions of Indiana and Ohio covered with loess, that it has been difficult to determine the relation of its underlying glacial deposits to the more irregular deposits found farther north. At an early period of recent investigations, while making a geological survey of the State of Wisconsin, President T. C. Chamberlin fixed upon the line of moraine hills, which can be seen upon our map, running southward between Green Bay ^ !ji V I '* y-i" < * « BSS:.™:' ■ :■■■ ^^H^^HH ii'i il.::^- ■■■■■■■■ 3m 's^Bs lEi 100 MAN AND THE GLACIAL PERIOD. and Lake Michigan, and sweeping around in a curve to the right, passing south of Madison and northward along the line of Wisconsin Eiver, and in another curve to the left, around the southern end of Lake Michigan, as the " ter- minal moraine of the second Glacial epoch." In Wiscon- sin the character of this line of moraine hills had been discovered and described by Colonel Charles Whittlesey, in 1866. It was first named the " kettle-moraine," because of the frequent occurrence in it of "kettle-holes." This line of moraine hills has been traced with a great degree of confidence across the entire glaciated area, as shown upon our map, but it is not everywhere equally distinct, and, as will be observed, follows a very irregular course. Beginning in Ohio we find it coinciding nearly with the extreme glacial boundary until it reaches the valley of the Scioto River, on the sixth meridian west from Wash- ington, where it begins to bear northward and continues in that direction for a distance of. sixty or seventy miles, and then turns southward again in the valley of the Miami, having formed between these two valleys a sort of medial moraine.* A similar medial moraine had also been noted by President Chamberlin between the valleys of the Grand and Cuyahoga Elvers, in the eastern part of Ohio. Indeed, for the whole distance across Ohio and Indiana, this moraine occurs in a series of loops pointing to the south, corresponding in general to the five gentle valleys which mark the territory, namely, those of the Grand and Mahoning Elvers ; the Sandusky and Scioto Rivers ; the Great Miami River ; the White Eiver ; and the Maumee and Wabash Elvers. Everywhere, however, over this area these morainic accumulations approximate pretty closely to the extreme boundary of the glaciated region. In Illinois President Chamberlin's original determina- tion of the moraine fixed it near the southern end of Lake * See map at the beginning of the chapter. ANCIENT GLACIERS. 101 Michigan, as shown upon our map, but Mr. Frank Leverett has subsequently demonstrated that there is a concentric series of moraines soutli of this, reaching across the State, (but somewhat obscured by superficial accumulations of loess referred to) and extending nearly to the latitude of St. Louis. West of Wisconsin President Chamberlin's " terminal moraine of the second Glacial epoch " bends southward through eastern Minnesota, and, sweeping down through central Iowa, forms, near the middle of the northern part of that State, a loop, having its southern extremity in the vicinity of Des Moines. The western arm of this loop runs through Minnesota in a northwesterly direction nearly parallel with the upper portion of the valley of the Minne- sota, until reaching the latitude of the head- waters of that river, where, in the vicinity of the Sisseton Agency, in Dakota, it turns to the south by an acute angle, and makes a loop in that State, extending to the vicinity of Yankton, and with the valley of the James River as its axis. The western arm of this loop follows pretty closely the line of the eastern edge of the trough of the Missouri River, con- stituting what is called the " Missouri Coteau," which continues on as a well-marked line of hills running in a northwesterly direction far up into the Dominion of Canada. One of the most puzzling glacial phenomena in the Mississippi Valley is the driftless area which occupies the southeastern portion of Minnesota, the southwestern part of Wisconsin, and the northwestern corner of Iowa, as de- lineated upon our map. This is an area which, whilrj being surrounded on every side by all the characteristic marks of glaciation, is itself conspicuous for their entire absence. Its rocks preserve no glacial scratches and are covered by no deposits of till, while northern boulders avoided it in their Journey to more southern latitudes. The reason for all this is not evident in the topography 102 MAN AKD THE GLACIAL PERIOD. of the region. The land is not higher than that to the north of it, nor is there any manifest protection to it by the highlands south of Lake Superior. Nor yet is there any reason to suppose that any extensive changes of level in former times seriously affected its relations to the sur- rounding country. Professor Dana, however, has called attention to the fact that even novi' it is in a region of comparatively light precipitation, suggesting that the snow-fall over it may always have been insignificant in amount. But this could scarcely account for the failure of the great ice-wave of the north to overrun it. We are indebted again to the sagacity of President Chamberlin in suggesting the true explanation. By referring to the map it will be noticed that this area sustains a peculiar relation to the troughs of Lake Michigan and Lake Superior, while from the arrange- ments of the moraines in front of these lakes it will be seen that these lake basins were prominent factors in determin- ing the direction of the movement of the surplus ice from the north. It is the more natural that they should do so because of their great depth, their bottoms being in both cases several hundred feet below the present water-level, reaching even below the level of the sea. These broad, deep channels seem to have furnished the readiest outlet for the surplus ice of the North, and so to have carried both currents of ice beyond this drif tless area before they became again confluent. The slight elevation south of Lake Superior served to protect the area on ac- count of the feebleness of direct movement made possible by the strength of these diverging lateral ice-currents. The phenomenon is almost exactly what occurs where a slight obstruction in a river causes an eddy and preserves a low portion of land below it from submergence. A glance at the map will make it easily credible that an ice- movement south of Manitoba, becoming confluent with one from Lake Superior, pushed far down into the Mis- ANCIENT GLACIEES. 103 souri Valley and spread eastward to the Mississippi Eiver, south of the unglaciated driftless area, and there became confluent with a similar movement which had been di- rected by the valleys of Lake Michigan and Lake Erie. There can be little doubt that President Chamberlin's ex- planation is in the main correct, and we have in this an- other illustration of the analogy between the behaviour of moving ice and that of moving water. Fig. 34.— Section of the east-and-west glacial furrows, on Kelly's Island, pre- served by Mr. Younglove. Fine sediment rests immediately on the rock, with washed pebbles at the surface. The accompanying illustrations will give a better idea than words can do of the celebrated glacial grooves on the hard limestone islands near Sandusky, in the western part 104 MAN AND THE GLACIAL PERIOD. of Lake Erie. Through the interest aroused in them by an excursion of the American Association for the Ad- vancement of Science, while meeting in Cleveland, Ohio, in 1888, the Kelly Island Lime and Transport Company, of which Mr. M. C. Younglove is the president, has been induced to deed to the Western Eeserve Historical So- ciety for preservation a portion of one of the most re- markable of the grooves still remaining. The portion of the groove preserved is thirty-three feet across, and the depth of the cut in the rock is seven- teen feet below the line, extending from rim to rim. Originally there was probably here a small depression formed by preglacial water erosion, into which the ice crowded the material, which became its graving-tool, and so the rasping and polishing went on in increasing degree until this enormous furrow is the result. The groove, however, is by no means simple, but presents a series of corrugations merging into each other by beautiful curves. When exposed for a considerable length it will resemble nothing else so much as a collection of prostrate Corin- thian columns lying side by side on a concave surface. The direction of these grooves is a little south of west, corresponding to that of the axis of the lake. This is nearly at right angles to the course of the ice-scratches on the summit of the water-shed south of this, between the lake and the Ohio Eiver. The reason for this change of direction can readily be seen by a little attention to the physical geography. The highlands to the south of the lake rise about seven hundred feet above it. When the Ice period was at its climax and overran these highlands, the ice took its natural course at right angles to the termi- nal moraine and flowed southeast according to the direc- tion indicated by the scratches on the summit ; but when the supply of ice was not sufficient to overrun the high- lands, the obstruction in front turned the course and the resultant was a motion towards Toledo and the Maumee fl^-^ 106 MAN AND THE GLACIAL PERIOD. Valley, where in the vicinity of Fort Wayne an extensive terminal moraine was formed. The much-mooted question of a succession of glacial epochs finds the most of its supporting facts in the por- tion of the glaciated area lying west of Pennsylvania. That there have been frequent oscillations of the glacial front over this area is certain. But it is a question whether the glacial deposits south of this distinct line of moraine hills are so different from those to the north of it as to necessitate the supposition of two entirely distinct glacial epochs. This can be considered most profitably here. The following are among the points with reference to which the phenomena south of the moraine just deline- ated differ from those north of the line : 1. The glacial deposits to the south appear to be dis- tributed more uniformly than those to the north. To the north the drift is often accumulated in hills, and is dotted over with kettle-holes, while to the south these are pretty generally absent. Any one travelling upon a line of rail- road which traverses these two portions of the glaciated area as indicated upon our map can easily verify these statements. 3. The amount of glacial erosion seems to be much less south of the line of moraine hills delineated than north of them. Still, glacial stris are found, almost every- where, close down to the extreme margin of the glaciated area. 3. The gravel deposits connected with the drainage of the Glacial period are much less abundant south of the so-called " terminal moraine of the second Glacial period " than they are north of it. South of this moraine the water deposits attributed to the Glacial period are of such fine silt as to indicate slow-moving currents over a gentle low slope of the surface. 4 The glacial deposits to the south are more deeply ANCIENT GLACIERS. 107 coloured than those to the north, showing that they have been longer exposed to oxidising agencies. Even the granitic boulders show the marks of greater age south of this line, being disintegrated to a greater extent than those to the north. 5. And, finally, there occur, over a wide belt bordering the so-called moraine hills of the second Glacial epoch, extensive intercalated beds of vegetal deposits. Among the earliest of these to be discovered were those of Mont- gomery County, Ohio, vs^here, in 1870, Professor Orton, of the Ohio Survey, found at Germantown a deposit of peat fourteen feet thick underneath ninety-five feet of till, and there seem also to be glacial deposits underneath the peat as well as over it. The upper portion of the peat contains " much undecomposed sphagnous mosses, grasses, and sedges, and both the peat and the clayey till above it " contain many fragments of coniferous wood which can be identified as red cedar {Juniperus Virginianus). In nu- merous other places in that portion of Ohio fresh-appear- ing logs, branches, and twigs of wood are found under- neath the till, or mingled with it, much as boulders are. Near Darrtown, in Butler County, Ohio, red cedar logs were found under a covering of sixty-five feet of till, and so fresh that the perfume of the wood is apparently as strong as ever. Similar facts occur in several other coun- ties in the glaciated area of southern Ohio and southern Indiana. Professor CoUett reports that all over south- western Indiana peat, muck, rotted stumps, branches, and leaves of trees are found from sixty to one hundred and twenty feet below the surface, and that these accumula- tions sometimes occur to a thickness of from two to twenty feet. Farther to the northwest similar phenomena occur. Professor N. H. Winchell has described them most par- ticularly in Fillmore and Mower Counties, Minnesota, from which they extend through a considerable portion of 108 MAN AND THE GLACIAL PERIOD. Iowa. In the above counties of Minnesota a stratum of peat from eighteen inches to six or eight feet in thickness, with much wood, is pretty uniformly encountered in dig- FiG. 36.— 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 stratification spoken of in the text can be seen about the middle of the picture. The farrows up and down had been made by recent rains. (United States Geological Survey.) (Wright.) ANCIENT GLACIERS. 109 ging wells, the depth varying from twenty to fifty feet. This county is near the highest divide in the State of Min- nesota, and from it "flow the sources of the streams to the north, south, and east." The wood encountered in this stratum indicates the prevalence of coniferous trees, and the peat mosses indicate a cool and moist climate. Nor are intercalated vegetable deposits absent from the vast region farther north over the area that drains into Hudson Bay. At Barnesville, in Clay County, Minnesota, which lies in the valley of the Eed Eivei- of the North, and also in Wilkin County in the same valley, tamarack wood and sandy black mud containing many snail-shells have been found from eight to twelve feet below a surface of till ; and Dr. Eobert Bell reports the occurrence of limited deposits of lignite between layers of till, far to the north- west, in Canada, and even upon the southern part of Hud- son Bay ; while Mr. J. E. Tyrrell reports * many indica- tions of successive periods of glaciation near the northern end of the Duck Mountain. The most characteristic in- dications which he had witnessed consisted of stratified beds of silt, containing fresh-water shells, with fragments of plants and fish similar to those living in the lakes of the region at the present time. Eeviewing these facts with reference to their bearing upon the point under consideration, we grant, at the out- set, that they do indicate a successive retreat and re- advance of the ice over extensive areas. This is specially clear with respect to the vegetal deposits interstratified with beds of glacial origin. But the question at issue concerning the interpretation of these phenomena is, Do they necessarily indicate absolutely disbinct glacial epochs separated by a period in which the ice had wholly disap- peared from the glaciated area to the north ? That they * Bulletin of the Geological Society of America, vol. i, pp. 395- 410. 110 MAN AND THE GLACIAL PERIOD. do, is maintained by President Ohamberliu and many oth- ers who have wide acquaintance with the facts. That they do not certainly indicate a complete disappearance of the ice during an extensive interglacial epoch, is capa- ble, however, of being maintained, without forfeiting one's rights to the respect of his fellow-geologists. The oppo- site theory is thus stated by Dr. Kobert Bell : " It appears as if all the phenomena might be referred to one general Glacial period, which was long continued, and conse- quently accompanied by varying conditions of tempera- ture, regional oscillations of the surface, and changes in the distributions of sea and land, and in the currents in the ocean. These changes would necessarily give rise to local variations in the climate, and might permit of vege- tation for a time in regions which need not have been far removed from extensive glaciers." * At my request, Professor J. E. Todd, of Iowa, whose acquaintance with the region is extensive, has kindly writ- ten out for me his conclusions upon this subject, which I am permitted to give in his own words : " I am not prepared to write as I would like concern- ing the forest-beds and old soils. I will, however, offer the following as a partial report. I have come to think that there is considerable confusion on the subject. I be- lieve there are five or six different things classed under one head. " 1. Recent Muck and Soils. — The finest example I have found in the whole Missouri Valley was twenty feet below silt and clay, in a basin inside the outer moraine, near Grand View, South Dakota. Prom my examination of the reported old soil near Albia, Iowa, I think the most rational way of reconciling the conflicting statements con- cerning it is that it also belongs to this class. * Bulletin of the Geological Society of America, vol. i, pp. 387- 310. ANCIENT GLACIERS. m " 2. Peat or Soil under Loess. — This does not signify much if the loess was formed in a lake subject to oro- graphic oscillations, or if, as I am coming to believe, it is a fluviatile deposit of an oscillating river like the Hoang-Ho on the great Chinese plain. It at least does not mean an interglacial epoch. " 3. Wood and Dirt rearranged, not in situ. — This occurs either in subaqueous or in subglacial deposits. I have found drift-wood in the lower layers of the loess here, but not in situ. I have frequently found traces of wood in till in Dakota, but always in an isolated way. I think, from reading statements about the deposits in east- ern Iowa, that most if not all of the cases are of this sort. Two things have conspired to lead to this error : one, the influence of CroU's speculation ; and the other, the easy inference of many well-diggers, and especially well-borers, that what they pass through are always in layers. In this way a log becomes a forest-bed. Scat- tered logs and muck fragments occurring frequently in a region, though at different levels, are readily imagined by an amateur geologist to be one continuous stratum ante- dating the glacier or floods (as the case may be in that particular region), when, in fact, it has been washed down from the margin of the transporting agent and is con- temporaneous with it. I suspect the prevalence of wood in eastern Iowa may be traced to a depression of the driftless region during the advance of the glacier, so as to bring the western side of that area more into the grasp of glacial agencies. " 4. Peat between Subglacial Tills. — If cases of this sort are found, they are in Illinois, Indiana, and Ohio. Pro- fessor Worthen insisted that there were no interglacial soils or forest-beds in Illinois ; and in the cases mentioned in the State reports he repeatedly explains the sections given by his assistants, so as to harmonize them with that statement. I think he usually makes his explanations 9 112 MAN AND THE GLACIAL PERIOD. plausible. He was yery confident in referring most of them to preglacial times. His views, I suppose, will be pub- lished in the long-delayed volume, now about to be issued. " 5. Vegetable Matter between Glacial Till and Under- lying Berg Till or other Drift Deposits. — When one remem- bers that the front of the great ice-sheet may have been as long in reaching its southern boundary as in receding from it, and with as many advance and retrograde move- ments, we can easily believe that much drift material would have outrun the ice and have formed deposits so far ahead of it that vegetation would have grown before the ice arrived to bury it. " 6. Preglacial Soils, etc. — I believe that this will be found to include most in southern Ohio, if not in Illinois, as Worth en claimed." The phenomena of the Glacial period are too vast either to have appeared or to have disappeared suddenly. By whatever cause the great accumulation of ice was pro- duced, the advance to the southward must have been slow and its disappearance must have been gradual, though, as we shall show a little later, the final retreat of the ice- front occupied but a short time relatively to the whole period which has elapsed since. As we shall show also, the advent of the Ice period was probably preceded and accompanied by a considerable elevation of the northern part of the continent Whether this elevation was con- temporaneous upon both sides of the continent is perhaps an open question ; but with reference to the area east of the Eocky Mountains, which is now under consideration, the centre of elevation was somewhere south of Hudson Bay. Putting together what we know, from the nature of the case, concerning the accumulation and movement of gla- cial ice, and what we know from the relics of the great glacial invasion, which have enabled us to determine its extent, and the vigour of its action, the course of events seems to have been about as follows : ANCIENT GLACIERS. 113 Throughout the Tertiary period a warm climate had prevailed over British America, Greenland, and indeed OTOr all the lands in proximity to the north pole, so far as explorers have been able to penetrate them. The vege- tation characterizing these regions during the Tertiary period indicates a temperature about like that which now prevails in North Carolina and Virginia. Whatever may be said in support of the theory that the Glacial period was produced by astronomical causes, in view of present facts those causes cannot be regarded as predominant ; at most they were only co-operative. The predominant cause of the Glacial period was probably a late Tertiary or post-Tertiary elevation of the northern part of the continents, accompanied with a subsidence in the cen- tral portion. Of such a subsidence in the Isthmus of Panama indications are thought to be afforded by the occurrence of late Tertiary or, more probably, post- Terti- ary sea-shells at a considerable elevation on the divide along the Isthmus of Panama, between the Atlantic and Pacific Oceans. Of this we shall speak more fully in a later chapter. Fixing our thoughts upon what is known as the Lau- rentian plateau, which, though now in the neighbourhood of but two thousand feet .above the sea, was then much higher, we can easily depict in imagination the begin- nings of the great " Laurentide Glacier," which eventually extended to the margin already delineated on the south and southwest in the United States, and spread north- ward and eastward over an undetermined area. Year after year and century after century the accumulating snows over this elevated region consolidated into glacial ice and slowly pushed outward the surplus reservoirs of cold. For a long time this process of ice-accumulation may have been accompanied by the continued elevation of the land, which, together with the natural effect of the enlarging area of ice and snow, would tend to lower the 114 MAN AND THE GLACIAL PERIOD. temperature around the margin and to increase still more the central area of accumulation. t The vigour of movement in any direction was deter- mined partly by the shape of the valleys opening south- ward in which the ice-streams would naturally concen- trate, and partly by those meteorological conditions which determine the extent of snow-fall over the local centres of glacial dispersion. Foi example, the general map of North America in the Ice period indicates that there were two marked subcentres of dispersion for the great Laurentide Glacier, the eastern one being in Labrador and the western one north of Lake Superior. In a general way the southern boundary of the glaciated re- gion in the United States presents the appearance of por- tions of two circumferences of circles intersecting each other near the eastern end of Lake Erie. These circles, I am inclined to believe, represent the areas over which a semi-fluid (or a substance like ice, which flows like a semi- fluid) would disperse itself from the subcentres above mentioned. A study of the contour of the country shows that that also, in a general way, probably had something to do with the lines of dispersion. The western lobe of this glaciated area corresponds in its boundary pretty closely with the Mississippi Valley, having the Ohio River approximately as its eastern arm and the Missouri as its western, with the Mississippi Eiver nearly in its north and south axis. The eastern lobe has its farthest extension in the axis of the Champlain and Hudson Eiver Valleys, its western boundary being thrown more and more northward as the line proceeds to the west over the Alleghany Mountains until reaching the longitude of the eastern end of Lake Brie ; but this southern boundary is by no means a water- level, nor is the contour of the country such that it could ever have been a water-level. But it conforms in nearly every particular to what would be the resultant arising ANCIENT GLACIERS. 115 from a pretty general southward flow of a semi-fluid from the two subcentres mentioned, meeting with the obstruc- tions of the Adirondacks in northern New York and of the broader Appalachian uplift in northern Pennsylvania. How far south the area of glacial accumulation may have extended cannot be deflnitely ascertained, but doubt- less at an early period of the great Ice age the northern portions of the Appalachian range in New York, New England, New Brunswick, and Nova Scotia became them- selves centres of dispersion, while only at the height of the period did all their glaciers become confluent, so that there was one continuous ice-sheet. , In the western portion of the area covered by the Lau- rentide Glacier, the depression occupied by the Great Lakes, especially Lakes Michigan and Superior, evidently had a marked influence in directing the flow of ice during the stages which were midway between the culmination of the Ice period and both its beginning and its end. This would follow from the great depth of these lakes, the bottom of Lake Michigan being 286 feet below sea- level, and that of Lake Superior 375 feet, making a total depth of water of about 900 and 1,000 feet respectively. Into these oblong depressions the ice would naturally gravitate until they were filled, and they would become the natural channels of subsequent movement in the di- rection of their longest diameters, while the great thick- ness of ice in them would make them the conservative centres of glacial accumulation and action after the ice had begun to retreat. These deductions from the known nature of ice and the known topography of the region are amply sustained by a study of the detailed map showing the glacial geol- ogy in the United States. But on this we can represent indeed only the marks left by the ice at various stages of its retreat, since, as already remarked, the marks of each stage of earlier advance would be obliterated by later for- 116 MAN AND THE GLACIAL PERIOD. ward movements. We may presume, however, that in general the marks left by the retreating ice correspond closely with those actually made and obliterated by the advancing movement. From observations upon the glaciers of Switzerland and of Alaska, it is found that neither the advance nor the retreat of these glaciers is constant, but that, in obe- dience to meteorologic agencies not fully understood, they advance and retreat in alternate periods, at one time receding for a considerable distance, and at other times regaining the lost ground and advancing over the area which has been uncovered by their retreat. " M. Forel reports, from the data which he has col- lected with much care, that there have been in this cent- ury 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 diminution, from 1845 to 1875 ; and of enlargement again, from 1875 onward. He remarks further that these periods corre- spond with those deduced by Mr. C. Lang for the varia- tions for the precipitations and temperature of the air ; and, consequently, that the enlargement of the glaciers has gone forward in the cold and rainy period, and the diminution in the warm and the dry."* When, now, we attentively consider the combination of causes necessary to produce the climatic conditions of the great Ice age of North America, we shall be prepared to find far more extensive variations in the progress of the continental glacier, both during its advance and dur- ing its retreat, than are to be observed in any existing local glaciers. With respect to the arguments adduced in favor of a succession of glacial epochs in America the following criticisms are pertinent : * American Journal of Science, vol. cxxrii, 1886, p. 77. ANCIENT GLACIERS. HY 1. So far as we can estimate, a temporary retreat of the front, lasting a few centuries, would be sufiBcient to account for the vegetable accumulations that are found buried beneath the glacial deposits in southern Ohio, In- diana, central Illinois, and Iowa, while a temporary re- advance of the ice would be sufiBcient to bury the vegeta- ble remains beneath a freshly accumulated mass of till. Thus, as Dr. Bell suggested, the interglacial vegetal de- posits do not necessarily indicate anything more than a temporary oscillation of the ice-front, and do not carry with them the necessity of supposing a disappearance of the ice from the whole glaciated area. Thus the introdiic- tion of a whole Glacial period to account for such limited phenomena is a violation of the well-known law of parsi- mony, which requires us in our explanations of phenomena to be content with the least cause which is suflScient to produce them. In the present instance a series of com- paratively slight oscillations of the ice-front during a single glacial period would seem to be sufiBcient to ac- count for all the buried forests and masses of vegetal debris that occur either in the United States or in the Dominion of Canada. 2. Another argument for the existence of two abso- lutely distinct glacial periods in North America has been drawn from the greater oxidation of the clays and the more extensive disintegration of certain classes of the bould- ers found over the southern part of the glaciated area of the Mississippi Valley, than has taken place in the more northerly regions. Without questioning this statement of fact (which, however, I believe to be somewhat exag- gerated), it is not difiBcult to see that the effects probably are just what would result from a single long glacial pe- riod brought about by such causes as we have seen to be probably in operation in America. For if one reflects upon the conditions existing when the Glacial period be- gan, he will see that, during the long ages of warm cli- 118 MAN AND THE GLACIAL PERIOD. mate which characterised the preceding period, the rocks must have been extensively disintegrated through the action of subaerial agencies. The extent to which this disintegration takes place can be appreciated now only by those who reside outside of the glaciated area, where these agencies have been in uninterrupted action. In the Appalachian range south of the glaciated region the gra- nitic masses and strata of gneiss are sometimes found to be completely disintegrated to a depth of fifty or sixty feet ; and what seem to be beds of gravel often prove in fact to be horizontal strata of gneiss from which the cementing material has been removed by the slow action of acids brought down by the percolating water. Now, there can be no question that this process of disintegration had proceeded to a vast extent before the Glacial period, so that, when the ice began to advance, there was an enormous amount of partially oxidised and disintegrated material ready to be scraped ofE with the first advance of ice, and this is the material which would naturally be transported farthest to the south ; and thus, on the theory of a single glacial period, we can readily ac- count for the greater apparent age of the glacial debris near the margin. This debris was old when the Glacial period began. 3. With reference to the argument for two distinct glacial periods drawn 'from the smaller apparent amount of glacial erosion over the southern part of the glaciated area, we have to remark that that would occur in case of a single ice-invasion as well as in case of two distinct ice- invasions, in which the later did not extend so far as the former. From the very necessity of the case, glacial erosion diminishes as the limit of the extent of the glaciation is approached. At the very margin of the glacier, motion has ceased altogether. Back one mile from the margin only one mile of ice-motion has been active in erosion, ANCIENT GLACIERS. 119 while ten miles back from its front there has been ten times as much moving ice actually engaged in erosion, and in the extreme north several hundred times as much ice. Thus it is evident that we do not need to resort to two glacial periods to account for the relatively small amount of erosion exhibited over the southern portion of our glaciated area. At the same time, it should be said that the indica- tions of active glacial erosion near the margin are by no means few or small. In Lawrence County, Pennsylvania, on the very margin of the glaciated area, Mr. Max Fo- shay * has discovered very extensive glacial grooves, indicat- ing much vigour of ice-action even beyond the more exten- sive glacial deposits which Professor Lewis and myself had fixed upon as the terminal moraine. In Highland and Butler Counties, Ohio, and in southwestern Indiana and southern Illinois, near the glacial margin, glacial grooves and strias are as clear and distinct in many cases as can anywhere be found ; while upon the surface of the lime- stone rocks within the limits of the city of St. Louis, where the glacial covering is thin, and where disintegrat- ing agencies had had special opportunities to work, I found very clear evidences of a powerful ice-movement, which had planed and scratched the rock surface; and at Du Quoin, Illinois, as already related, the fragments thrown up from the surface of the rock, fifty or sixty feet below the top of the soil, were most beautifully planed and striated. It should be observed, also, that this whole area is so deeply covered with debris that the extent of glacial erosion underneath is pretty generally hid from view. 4. The uniformity of the distribution of the glacial deposits over the southern portion of the glaciated area in the Mississippi Valley is partly an illusion, due to the * Bulletin of the Geological Society, vol. ii, pp. 457-464. 120 MAN AND THE GLACIAL PERIOD. fact that there was a vast amount of deposition by water over that area during the earlier stages of the ice-retreat. This has been due partly to the gentler slope which would naturally characterise the borders of an area of elevation, and partly to an extensive subsidence which seems to have begun soon after the ice had reached its farthest extent of motion. It should be borne in mind that at all times a glacier is accompanied by the issue of vast streams of water from its front, and that these of ciDurse increase in volume when the climax has been reached and the ameliorating influ- ences begin to melt away the accumulated mass of ice and to add the volume of its water to that produced by ordinary agencies. As these subglacial streams of water poured out upon the more gentle slopes of the area in front of the ice, they would distribute a vast amount of fine material, which would settle into the hollow places and tend to obscure the irregularities of the previous di- rect glacial deposit. Such an instance came clearly under my own observa- tion in the vicinity of Yankton, in South Dakota, where, upon visiting a locality some miles from any river, and to which workmen were resorting for sand, I found that the deposit occupied a kettle-hole, filling it to its brim, and had evidently been superimposed by a temporary stream of water flowing over the region while the ice was still in partial occupation of it. Thus, no doubt, in many cases, the original irregularities of the direct glacial deposits have been obliterated, even where there has been no gen- eral subsidence. But, in the area under consideration, the loess, or loam, is so extensive that it is perhaps necessary to sup- pose that the central portions of the Mississippi Valley were subjected to a subsidence amounting to about five hundred feet ; so that the glacial streams from the retreat- ing ice-front met the waters of the ocean in southern ANCIENT GLACIERS. 121 Illinois and Indiana; thus accounting for the extensive fine silt which has done so much over that region to obscure the glacial phenomena. West of the Rocky Mountains. The glacial phenomena in the United States west of the Rocky Mountains must be treated separately, since American geologists have ceased to speak of an all-per- vading ice-cap extending from the north pole. But, as already said, the glaciation of North America has proceed- ed from two definite centres of ice-accumulation, one of which we have been considering in the pages immediately preceding. The great centre of glacial dispersion east of the Rocky Mountains is the region south of Hudson Bay, and the vast ice-field spreading out from that centre is appropriately named the Laurentide Glacier. The move- ment of ice in this glacial system was outward in all directions from the Laurentian hills, and extended west several hundred miles, well on towards the eastern foot of the Rocky Mountains. The second great centre of glacial dispersion occupies the vast Cordilleran region of British Columbia, reaching from the Rocky Mountains on the northeast to the Coast Range of the Pacific on the southwest, a width of four hundred miles. The length is estimated by Dr. Dawson to be twelve hundred miles. The principal centre of ice- accumulation lies between the fifty-fifth and the fifty- ninth parallel. From this centre the movement was in all directions, but chiefly to the northwest and to the south. The movement of the Cordilleran glaciers ex- tended northwest to a distance of three hundred and fifty miles, leaving their moraines far down in the Yukon Valley on the Lewes and Pelly Rivers.* Southward the * See George M. Dawson, in Science, vol. xi, 1888, p. 186, and American Geologist, September, 1890, pp. 153-162. 122 MAN AND THE GLACIAL PERIOD. Cordilleran Glacier moved to a distance of six hundred miles, extending to the Columbia River, in the eastern part of the State of Washington. From this centre, also, the ice descended to the sea- level upon the west, and filled all the channels between Vancouver's Island and the mainland, as well as those in the Alexander Archipelago of Alaska. South of Van- couver's Island a glacier pushed out through the straits of Juan de Fuca to an unknown distance. All the islands in Puget Sound are composed of glacial debris, resem- bling in every respect the terminal moraines which have been described as constituting many of the islands south of the New England coast. The ice-movement in Puget Sound, however, was probably northward, resulting from glaciers which are now represented by their diminutive descendants on the flanks of Mount Eainier. South of the Columbia River the country was never completely enveloped by the ice, but glaciers extended far down in the valleys from all the lofty mountain-peaks. In Idaho there are glacial signs from the summit of the Rocky Mountains down to the westward of Lake Pend d'Oreille. In the Yellowstone Park there are clear indications that the whole area was enveloped in glacial ice. An immense boulder of granite, resting upon volcanic deposits, may be found a little west of Inspiration Point, on the Yellow- stone Caflon. Abundant evidences of glacial action are also visible down the Yellowstone River to the vicinity of Livingston, showing that that valley must have been filled with glacial ice to a depth of sixteen hundred feet. To the west the glaciers from the Yellowstone Park ex- tended to the border of Idaho, where a clearly marked terminal moraine is to be found in the Tyghee Pass, lead- ing over from the western fork of the Madison River into Lewis Fork of the Snake River. South of Yellowstone Park the Teton Mountains were an important centre for the dispersion of local glaciers, but they did not descend ANCIENT GLACIERS. 123 upon the western side much below the 6,000-foot leyel, and only barely came to the edge of the great Snake River lava plains. To the east the movement from the Teton Mountains joined that from various other lofty mountains, where altogether they have left a most intri- cate system of glacial deposits, in whose reticulations Jack- son's Lake is held in place. In Utah extensive glaciers filled all the northern val- leys of the Uintah Mountains, and extended westward in the Wahsatch range to the vicinity of Salt Lake City. The mountain region of Colorado, also, had its glaciers, Fig. 37. — Moraines of Grape Creek, Sangre del Cristo Moontaius, Colorado (after Stevenson). occupying the head- waters of the Arkansas, the Platte, the Gunnison, and the Grand Rivers. The most southern point in the Rocky Mountains at which signs of local glaciers have been noted is near the summits of the San 124 MAN AND THE GLACIAL PERIOD. Juan range, in southwestern Colorado. Here a surface of about twenty-five square miles, extending from an eleva- tion of 13,000 feet down to 8,000 feet, shows every sign of the former presence of moving ice. The greater part of the glaciation in Colorado is confined to elevations above 10,000 feet. The wljole range of the Sierra Nevada through Ore- gon, and as far south as the Yosemite Valley in Califor- nia, formerly sustained glaciers of far greater size than any which are now found in those mountains. In general these glaciers were much longer on the western side of the Sierra Nevada than on the eastern. On the eastern side glaciers barely came down to Lake Tahoe and Lake Mono in California. The State of Nevada seems to have been entirely free from glaciers, although it contains numer- ous mountain-peaks more than ten thousand feet high. In the Yosemite Caflon glaciers extended down the Mer- ced Eiver to the mouth of the cafion ; while in the Tuo- lumne River, a few miles to the north, the glaciers which still linger about the peaks of Mount Dana filled the val- ley for a distance of forty miles. It is a question among geologists whether or not the glaciation west of the Rocky Mountains was contempo- raneous with that of the eastern part of the continent. The more prevalent opinion among those who have made special study of the phenomena is that the development of the Cordilleran glaciers was independent of that of the Laurentide system. At any rate, the intense glaciation of the Pacific coast seems to have been considerably later than that of the Atlantic region. Of this we will speak more particularly in discussing the questions of the date and the cause of the Glacial period. It is sufficient for us here simply to say that, from his extensive field observa- tions throughout the Cordilleran region, Dr. George M. Dawson infers that there have been several successive al- ternations of level on the Pacific coast corresponding to ANCIENT GLACIERS. 125 successive glacial and interglacial epochs, and that when there was a period of elevation west of the Rocky Mount- ains there was a period of subsidence to the east, and vice versa. In short, he supposes that the east and west for a long time played a game of seesaw, with the Eocky Mountains as the fulcrum. We give his scheme in tabu- lated form. Scheme of Correlation of the Phenomena of the Glacial Period in the Cordilleran Region and in the Region of the Great Plains. COEDILLERAN REGION. Cordilleran zone at a high elevation. Period of most severe glaciation and maximum devel- opment of the great Cordilleran Glacier. Gradual subsidence of the Cordilleran region and decay of the great glacier, with deposition of the boulder-clay of the interi- or plateau and the Yukon basin, of the lower boulder-clay of the littoral and probably also, at a later stage (and with greater sub- mergence), of the interglacial silts of the same region. Re-elevation of the Cordil- leran region to a level probably as high as or somewhat higher than the present. Maximum of second period of glaciation. REGION OF THE GREAT PLAINS. Correlative subsidence and submergence of the great plains, with possible contemporaneous increased elevation of the Lau- rentian axis and maximum de- velopment of ice upon it. De- position of the lower boulder- clay of the plains. Correlative elevation of the western part, at least, of the great plains, which was probably more or less irregular and led to the production of extensive lakes in which interglacial deposits, in- cluding peat, were formed. Correlative subsidence of the plains, which (at least in the western part of the region) ex- ceeded the first subsidence and extended submergence to the base of the Rocky Mountains near the forty-ninth parallel. Formation of second boulder-clay, and (at a later stage) dispersion of large erratics. 126 MAN AND THE GLACIAL PERIOD. Partial subsidence of the Cor- dilleran region, to a level about 3,500 feet lower than the present. Long stage of stability. Glaciers of the second period considerably reduced. Upper boulder-clay of the coast probably formed at this time, though perhaps in part dur- ing the second maximum of gla- ciation. Renewed elevation of the Cor- dilleran region, with one well- marked pause, during which the littoral stood about 200 feet lower than at present. Glaciers much reduced, and diminishing in con- sequence of general amelioration of climate towards the close of the Glacial period. Correlative elevation of the plains, or at least of their west- ern portion, resulting in a condi- tion of equilibrium as between the plains and the Cordillera, their relative levels becoming nearly as at present. Probable formation of the Missouri co- teau along a shore-line during this period of rest. Simultaneous elevation of the great plains to about their pres- ent level, with final exclusion of waters in connection with the sea. Lake Agassiz formed and eventually drained towards the close of this period. This simul- taneous movement in elevation of both great areas may probably have been connected with a more general northern elevation of land at the close of the Glacial period. In New Zealand the marks of the Glacial period are unequivocaL The glaciers which now come down from the lofty mountains upon the South Island of New Zea- land to within a few hundred feet of the sea then de- scended to the sea-level. The longest existing glacier in New Zealand is sixteen miles, but formerly one of them had a length of seventy-eight miles. One of the ancient moraines contains a boulder from thirty to forty feet in diameter, and the amount of glacial debris covering the mountain-sides is said to be enormous. Eeports have also been recently brought of signs of ancient glaciers in Aus- tralia. According to Darwin, there are distinct signs of glacia- tion upon the plains of Patagonia sixty or seventy miles east of the foot of the mountains, and in the Straits of Ma- ANCIENT GLACIERS. 127 gellan he found great masses of unstratified glacial material containing boulders wHch were at least one hundred and thirty miles away from their parent rock ; while upon the Fis 38 —Generalised Tiew of the whole glaciated region of North America. The area of motlonleas ground-ice is shown by the white lines in northern part of Alaska. 10 128 MAN AND THE GLACIAL PERIOD. island of Chiloe he found embedded in " hardened mud " boulders ■vrhieh must have come from the mountain-chains of the continent. Agassiz also observed unquestionable glacial phenomena on various parts of the Fuegian coast, and indeed everywhere on the continent south of latitude 37°. Between Concepcion and Arauco, in latitude 37°, Agassiz observed, near the sea-level, a glacial surface well marked with furrows and scratches, and as well preserved, he says, " as any he had seen under the glaciers of the present day." Pig. 39.— Qnartzite bonlder of 45 cubic metres, on Mont Lachat, 800 metres above the valley of the Belley, In Ain, Prance (Palsan). CHAPTEK VI. ANCIENT GLACIERS IN THE EASTERN HEMISPHERE. About two million square miles of riorthern Europe were covered with perennial ice during the Glacial period. From the scratches upon the rocks, and from the direction in which material has been transported, it is evident that the main centre of radiation is to be found in the mount- ains of Scandinavia, and that the glaciers still existing in Norway are the lineal descendants of those of the great Ice age. So shallow are the Baltic Sea and the German Ocean, that their basins were easily filled with ice, upon which Scandinavian boulders could be transported westward to the east shore of England, southward into the plains of Germany, and eastward far out upon the steppes of Eussia. The islands north of Scotland bear marks also of an ice- movement from the direction of Norway. If Scotland itself was not overrun with Scandinavian glaciers, the reason was that it had ice enough of its own, and from its highlands set up a counter-movement, which success- fully resisted the invasion from the Scandinavian Penin- sula. But, elsewhere in Europe, Scandinavian ice moved freely outward to the extent of its capacity. Then, as now also, the Alps furnished centres for ice-movement, but the glaciers were limited to the upper portions of the valleys of the Kh6ne, the Ehine, and the Danube upon the west and north, and to a still smaller area upon the southern side. ANCIENT GLACIERS IN EASTERN HEMISPHERE. 131 Central and /Southern Europe. The main centres of ice-movement in the Alps during the Glacial period are the same as those which furnish the lingering glaciers of the present time. From the water-shed between the Ehine, the Kh6ne, and the Aar, glaciers of immense size descended all the valleys now occupied by those streams. The valley of the Kh6ne be- tween the Bernese and the Pennine Alps was filled with a glacier of immense depth, which was maintained by fresh supplies from tributaries upon either side as far down as Martigny. Glacial markings at the head of the Eh6ne Valley are found upon the Schneestock,* at an elevation above the sea of about 11,500 feet (3,550 metres), or about 1,500 feet above the present surface of the Rhone Glacier. At Fiesch, about twenty miles below, where tributaries from the Bernese Oberland snow-fields were received, the thickness of the glacier was upwards of 5,000 feet (1,680 metres). Near Martigny, about fifty miles farther down the valley, where the glacier was abruptly de- flected to the north, the depth of the ice was still upwards of 1,600 metres. From Martigny northward the thick- ness of the ice decreased rapidly for a few miles, where, at the enlargement of the valley above the head of Lake Geneva, it was less than 1,200 metres in thickness, and spread out over the intervening plain as far as Chasseron, with a nearly level surface, transporting, as we have before said, Alpine boulders to the flanks of the Juras, and land- ing them about 3,000 feet (1,375 metres) above the level of Lake Geneva. The width of the main valley is here about fifty miles, making the slope of the surface of the ice about twenty feet to the mile. From its " vomitory," at the head of Lake Geneva, the * A. Falsan's La Perlode Glaeiaire etudiee prinoipalement en France et en Suisse, chapitre xv. 132 MAN AND THE GLACIAL PERIOD. ice of the ancient Eli6ne Glacier spread to the right and to the left, while its northern boundary was abruptly ter- minated by the line of the Jura Mountains. The law of glacial motion was, however, admirably illustrated in the height to which the ice rose upon the flanks of the Jura. At Ghasseron, in the direct line of its onward motion, it rose to its highest point, while both to the southwest and to the northeast, along the line of the Juras, the ice- action was limited to constantly decreasing levels. Down the valley of the Ehdne the direction of motion was determined by the depression of Lake Geneva, at the lower end of which it received its main tributary from Mont Blanc, which had come down from Chamouni through the valley of the river Arve. Prom this point it was deflected by a spur of the Jura Mountains more and more southward to the vicinity of Culoz, near the mouth of Lake Bourget. Here the glacier coming down from the western flanks of the Alps, through the upper valley of the Is^re, past Chambery, became predominant, and deflected the motion to the west and north, whither the ice extended to a line passing through Bourg, Lyons, and Vienne, leaving upon one of the eminences on which Lyons is built a boulder several feet in diameter, which is duly preserved and labelled in the public park in that portion of the city. Farther south, glaciers of less extent marked the Alps most, of the way to the Mediterranean, but they were not at all comparable in size to those from the central region. To the right of Lake Geneva the movement started by the Rh6ne Glacier spread eastward, being joined in the vicinity of Berne by the confluent ice-stream which de- scended from the north flank of the Bernese Oberland, through the valley of the Aar. These united streams filled the whole valley with ice as far down as Soleure.* * See map of RhSne Glacier, on p. 58, ANCIENT GLACIERS IN EASTERN HEMISPHERE.. I33 Farther eastward, other ice-streams from the Alps be- came predominant, one of which, moving down the Keuss, deployed out upon the country lying north of Lucerne and Zug. Still farther down, the ancient glacier which descended the Limmatt spread itself out over the hills and lowlands about Zurich, one of its moraines of retro- cession nearly dividing the lake into two portions. Guyot and others have shown that the superficial de- posits of this portion of Switzerland are just such as would be distributed by glaciers coming down from the above- mentioned Alpine valleys. Uniting together north of Zurich, these glaciers pushed onward as far as the Ehine below Schaffhausen. In Frickthal the glacial ice was still 1,300 feet thick, and at Kaisterberg between 400 and 500 feet. At Lucerne there is a remarkable exposure of pot- holes, and a glaciated surface such as could be produced only by the combined action of moving ice and running water; thus furnishing to tourists an instructive object- lesson. Among the remarkable instances of boulders transported a long distance in Switzerland, is that of a block of granite carried from the Valais to the vicinity of Soleure, a distance of one hundred and fifteen miles, which weighs about 4,100 tons. "The celebrated Pierre -a-Bot, above Neufchdtel, measures 50' X 20' X 40', and contains about 40,000 cubic feet of stone; while the Pierre-des- Marmettes, near Monthey, contains no less than 60,840 cubic feet." The ancient glacier of the Ehine, receiving its initial impulse in the same centre as that of the Eh6ne, fully equalled it in all its dimensions. Descending eastward from its source near the Schneestock to Chur, a distance of fifty miles, it turned northward and continued forty- five miles farther to the head of Lake Constance, where it spread out in fan-shape, extending northwest to Thiengen, below Schaffhausen, and covering a considerable area north 134- MAN AND THE GLACIAL PERIOD. and northeastward of the lake, reaching in the latter di- rection trim, upon the Danube — the whole distance of the movement being more than one hundred and fifty miles. Through other valleys tributary to the Danube, glaciers descended upon the upper plains of Bavaria, from the Tyrolese Alps to the vicinity of Munich. From Gross Glockner as a centre in the Noric Alps, vast rivers of ice, of which the Pasterzen Glacier is the remnant, poured far down into the valleys of the Inn and the Enns on the north and into that of the Drave on the southeast. Farther eastward in this part of Europe the mountains seem to have been too low to have furnished centres for any general dispersion of glacial ice. Upon the south side of the Alps the ancient glaciers spread far out upon the plains of Lombardy, where mo- raines of vast extent and of every descrip- tion enable the stu- dent to determine the exact limits of the ancient ice - action. Prom the southern flanks of Mont Blanc and Monte Rosa, and from the snow-fields of the western Alps, glaciers of great vol- ume descended into the valley of Dora Baltea (vale of Aos- , . , .. , „„ . ta), and on emerging Fig. 41. — Map showing the Lines of Debris en- ' . tending from the Alps into the Plains of the from the mountain Po (after Lyell). .<1. Crest of the Alpine wa- ter-shed ; B, Neve fields of the ancient gla- valley Spread OUt OVer ciers ; C, Moraines of ancient glaciers. , ,'. , the plains around Ivrea, leaving moraine hills in some instances 1,500 feet in height. The total length of this glacier was as much as ANCIENT GLACIERS IN EASTERN HEMISPHERE. I35 one hundred and twenty miles. From the snow-fields in the vicinity of Mont Oenis, also, glaciers extended down the Dora Kipera to the vicinity of Turin, and down other valleys to a less extent. The lateral moraines of the Diore, on the south side of Mont Blanc, at the head of the Dora Baltea, are 2,000 feet above the present river, and extend upon the left bank for a distance of twenty miles. From the eastern Alps, glaciers descended through all the valleys of the Italian lakes and deposited vast terminal moraines, which still obstruct the drainage, and produce the charming lakes of that region. A special historic interest pertains to the series of concentric moraines south of Lake Garda, since it was in the reticulations of this glacial deposit that the last great battle for Italian liberty was fought on June 34, 1859. Defeated in the engage- ments farther up the valley of the Po, the Austrian general Benedek took his final stand to resist the united forces of France and Italy behind an ' outer semicircle of the moraine hills south of this lake (some of which are 500 or 600 feet above the surrounding country), with his centre at Solferino, about ten miles from Peschera. Here, behind this natural fortification, he awaited the enemy, who was compelled to perform his manoeuvres on the open plain which spread out on every side. But the natural fortifications furnished by the moraine hills were too ex- tensive to be defended by an army of moderate size. The troops of Napoleon and Victor Immanuel concentrated at Solferino and broke through the line. Thus the day was lost to the Austrians, and they retired from Lombardy, leaving to Italy both the artificial and the natural fortifi- cations that guard the southern end of this important entrance to the Tyrolese Alps. When once his attention is called to the subject, the traveller upon the railroad cannot fail to notice this series of moraines, as he enters it through a tunnel at Lonato on the west, and emerges from it at Soma Oampagna, eighteen or twenty miles dia- 136 MAN AND THE GLACIAL PERIOD. tant to the east. A monument celebrating the victory stands upon a moraine hill about half-way between, at Martino della Battaglie. In other portions of central and southern Europe the mountains were too low to furnish important centres for glacial movements. Still, to a limited extent, the signs of ancient glaciers are seen in the mountains of the Black Forest, in the Harz and Erzgebirge, and in the Carpathians on the east and among the Apennines on the south. In Spain, also, there were limited ice-fields on the higher por- tions of the Sierra Nevada and in the mountains of Estre- madura, and perhaps in some other places. 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 Pyrenees, glaciers extended northward throughout nearly their whole extent. The ice-stream descending from the central mass of Maladetta through the upper Valley of the Garonne, was joined by several tributaries, and attained a length of about forty- five miles. The British Isles. During the climax of the Glacial period the Hebrides to the north of Scotland were covered with ice to a depth of 1,600 feet. How far westward of this it moved out to the sea, it is of course impossible to tell. But in the channels between the Hebrides and Scotland it is evident that the water was completely expelled by the ice, and that, from a height of 1,600 feet above the Hebrides to the northern shores of Scotland, there was a continuous ice- field sloping southward at the rate of about twenty-five feet a mile. Scotland itself was completely enveloped in glacial ice. Prevented by the Scandinavian Glacier from moving east- ward, the Scotch movement was compelled to be westward and southward. On the southwest the ice-stream reached ANCIENT GLACIERS IN EASTERN HEMISPHERE. I37 the shores of Ireland, and became confluent with the glaciers that enveloped that island, completely filling the Irish Sea. There are so many controverted points respecting the glacial geology of England, and they have such an impor- tant bearing upon the main question of this volume, that a pretty full discussion of them will be necessary. I have recently been over enough of the ground myself to become satisfied of the general correctness of the views entertained by my late colleague, the lamented Professor Henry Car- vill Lewis, whose death in 1888 took place before the pub- lication of his most mature conclusions. But the lines of investigation to which he gave so powerful an impulse have since been followed out by an active body of scien- tific observers. To give the statement of facts greater precision and authority, I have committed the preparation of it to the Secretary of the Northwest of England Boul- der Committee, Percy E. Kendall, F. G. S., Lecturer on Geology at the Yorkshire College, Leeds, and at the Stockport Technical School, England.* " All the characteristic evidences of the action of land- ice can be found in the greatest perfection in many parts of England and Wales. Drumlins, kames, roches mouton- nees, far-travelled erratics, terminal moraines, and perched blocks, all occur. There are, besides, in the wide-spread deposits of boulder-clay which cover so many thousands of square miles on the low grounds lying oii either side of the Pennine chain, evidences of the operation of ice- masses of a size far exceeding that of the grandest of ex- isting European glaciers. But, while the proofs of pro- tracted and severe glaciation are thus patent, there are, nevertheless, many apparently anomalous circumstances which arrest the attention when the whole country is sur- veyed. The glacial phenomena appear to be strictly lim- ited to the country lying to the northward of a line ex- * HJ.r, Kendall's contribution extends to page 181, 138 MAN AND THE GLACIAL PERIOD. tending from the Bristol Channel to the mouth of the Thames ; and within the glaciated area there are many extensive tracts of land devoid of ' drift ' or other indi- cations of ice-action. " By comparison with the phenomena displayed in the North American continent, English glacial geology must seem puny and insignificant ; but, just as with the feat- ures of the ' Solid Geology,' we have compressed within the narrow limits of our isles an epitome of the features which across the Atlantic require a continent for their exposition. It has resulted from this concentration that English geology requires a much closer and more minute investigation. And the difficulty which has been experi- enced by glacial geologists of dealing with an involved series of facts has, in the absence of any clue leading to the co-ordination of a vast series of more or less disconnected observations, resulted in the adoption, to meet certain local anomalies, of explanations which were very difficult if not impossible of reconciliation with facts observed in adjacent areas. Thus, to account for shell-bearing drift extending up to the water-shed on one side of a lofty range of hills, a submergence of the land to a depth of 1,400 feet has been postulated ; leaving for independent explanation the fact, that the opposite slopes of the hills and the low ground beyond were absolutely destitute of drift or of any evidence of marine action. " In the following pages I must adopt a somewhat dog- matic tone, in order to confine myself within the limits of space which are imposed ; and trust rather to the cohesion and consistency of the explanations offered and to a few pregnant facts than to the weighing and contrasting of rival theories. " The facts point conclusively to the action in the Brit- ish Isles of a series of glaciers radiating outward from the great hill chains or clusters, and, as the refrigeration pro- gressed, becoming confluent and moving though in the ANCIENT GLACIERS IN EASTERN HEMISPHERE. 139 same general direction, yet with less regard to the minor inequalities of the ground. During these two stages many glaciers must have debouched upon the sea-coast, with the consequent production of icebergs, which floated off with loads of boulders and dispersed them in the random fash- ion which is a necessary characteristic of transport by floating ice. " With a further accentuation of the cold conditions the discharge of bergs from terminal fronts which advanced into the extremely shallow seas surrounding the British shores would be quite inadequate to relieve the great press of ice, and a further coalescence of separate elements must have resulted. In the case of enclosed seas — as, for exam- ple, the Irish Sea — the continued inthrust of glacier-ice would expel the water completely ; and the conjoined ice- masses would take a direction of flow the resultant of the momentum and direction of the constituent elements. In other cases — as, for example, in the North Sea — extraneous ice approaching the shores might cause a deflection of the flow of the native glaciers, even tiiough the foreign ice might never actually reach the shore. " To such a system of confluent glaciers, and to the separate elements out of which they grew, and into which, after the culmination, they were resolved, I attribute the whole of the phenomena of the English and Welsh drift. And only at one or two points upon the coast, and raised but little above the sea-level, can I recognise any signs of marine action. " The Pre-glacial Level of the Land. — There is very lit- tle direct evidence bearing upon this point. In Norfolk the famous forest bed, with its associated deposits, stands at almost precisely the level which it occupied in pre-glacial times. At Sewerby, near Flamborough Head, there is an ancient beach and ' buried cliff ' which the sea is now de- nuding of its swathing of drift deposits, and its level can be seen to be almost absolutely coincident with the present 140 MAN AND THE GLACIAL PERIOD. beach. Mr. Lamplugh, whose description of the ' Drifts of Plamborough Head,' * constitutes one of the gems of glacial literature, considers that there is clear evidence that the land stood at this level for a long period. The beach is covered by a rain- wash of small extent, and that in turn by an ancient deposit of blown sand, while the lowest member of the drift series of Yorkshire covers the whole. Mr. Lamplugh thinks that the blown sand may indicate a slight elevation of the land ; but the beach ap- pears to me to be the storm beach, and the reduction in the force of the waves such as would result from the ap- proach of an ice-front a few miles to the seaward would probably produce the necessary conditions. " Six miles to the northward of Flamborough, at Spee- ton, a bed of estuarine silt containing the remains of mol- lusca in the position of life occurs at an altitude of ninety feet above high-water mark. Mr. Lamplugh inclines to the opinion that this bed is of earlier date than the ' buried clifE ' ; he also admits the possibility that its superior alti- tude may be due to a purely local upward bulging of the soft Lower Cretaceous clays upon which the estuarine bed rests by the weight of the adjacent lofty chalk escarp- ment. " The evidence obtained from inland sections and bor- ings in different parts of England has been taken to in- dicate a greater altitude in preglacial times. Thus, in Essex, deep borings have revealed the existence of deep drift-filled valleys, having their floors below sea-level. The valley of the Mersey is a still better example. Nu- merous borings have been made in the neighbourhood of Widnes and at other places in the lower reaches of the river, making it clear that there is a channel filled with drift and extending to 146 feet below mean sea-level. This, with several other instances, has been taken to in- * Quarterly Journal of the Geological Society, vol. xlvii. ANCIENT GLACIERS IN EASTERN HEMISPHERE. 141 dicate a greater altitude for the land in pre-glacial times, since a river could not erode its channel to such a depth below sea-level. The argument appears inconclusive for one principal reason : no mention is made of any river gravels or other alluvium in the borings. Indeed, there is an explicit statement that the deposits are all glacial, showing that the channel must have been cleared out by ice. This, therefore, leaves open the vital question, whether the deposits removed were marine or fluviatile. It may be remarked that the great estuary of the Mersey has undoubtedly been produced by a post-glacial (and probably post-Eoman) movement of depression. " The Pre- Glacial Climate. — In all speculations regard- ing the cause of the Glacial epoch, due account must be taken of the undoubted fact that it came on with extreme slowness and departed with comparative suddenness. In the east of England an almost perfect and uninterrupted sequence of deposits is preserved, extending from the early part of the Pliocene period down to the present day. " These in descending order are : " 1. Post-glacial sands, gravels, etc. " 3. Glacial series. " 3. The ' Forest Bed ' and associated marine deposits. " 4. Ohillesford clay and sand. " 5. The many successive stages of the Eed Crag. (The Norwich Crag is a local variation of the upper part of the Red Crag.) " 6. The Coralline Crag. " The fossils preserved in these deposits, apart from the physical indications, exhibit the climatal changes which accompanied their deposition. The Coralline Crag con- tains a fauna consisting mainly of species which now range to the Mediterranean, many of them being restricted to the warm southern waters. Associated with these are a few boreal forms, but they are represented in general by few individuals. Here and there in the deposits of 142 MAN AND THE GLACIAL PERIOD. this age far-travelled stones are to be found, but they are always accounted great rarities. " The Bed Crag consists of an irregular assemblage of beaches and sand-banks of widely different ages, but their sequence can be made out with ease by a study of the fauna. In the oldest deposits, Mediterranean species are very numerous, while the boreal forms are comparatively rare ; but in successive later deposits the proportions are very gradually reversed, and from the overlying Chilles- ford series the Mediterranean species are practically ab- sent. The physical indications run pari passu with the paleoatological, and in the newer beds of the Eed Crag far-travelled stones are common. " In the Forest Bed series there is a marine band — the Leda myalis bed — which contains an almost arctic assem- blage of shells ; while at about the same horizon plant remains have been found, including such high northern species as Salix polaris and Betula nana. " The glacial deposits do not, in my opinion, contain anywhere in England or Wales a genuine intrinsic fauna, such shells as occur in the East Anglian glacial deposits having been derived in part from a contemporary sea-bed, and, for the rest, from the older formations, down perhaps to the Coralline Crag. In the post-glacial deposits we have hardly any trace of a survival of the boreal forms, and I consider that the whole marine fauna of the North Sea was entirely obliterated at the culmination of the Glacial epoch, and that the repeopling in post-glacial times proceeded mainly from the English Channel, into which the northern forms never penetrated. " The Great Glacial Centres. " Where such complex interactions have to be described as were produced by the conflicting glaciers of the British Isles it is difficult to deal consecutively with the phe- nomena of any one area, but with short digressions in ex- ANCIENT GLACIERS IN EASTERN HEMISPHERE. 143 planation of special points it may be possible to accom- plish a clear presentation of the facts. " Wales. — The phenomena of South Wales are com- paratively simple. Great glaciers travelled due southward from the lofty Brecknock Beacons, and left the charac- teristic moutonnee appearance upon the rocky bed over which they moved. The boulder-transport is in entire agreement with the other indications, and there are no shells in the drift. The facts awaiting explanation are the occurrence in the boulder-clays of Glamorganshire, at altitudes up to four hundred feet, of flints, and of igneous rocks somewhat resembling those of the Archaean series of the Wrekin. At Clun, in Shropshire, a train of erratics (see map) has been traced back to its source to the west- ward. On the west coast, in Cardigan Bay, the boulders are all such as might have been derived from the interior of Wales. At St. David's Peninsula, Pembrokeshire, strisB occur coming in from the northwest, and, taken with the discovery of boulders of northern rocks, may point to a southward extension of a great glacier produced by conflu- ent sheets that choked the Irish Sea. Information is very scanty regarding large areas in mid- Wales, but such as can be gathered seems to point to ice-shedding having taken place from a north and south parting line. In North Wales, much admirable work has been done which clearly indicates the neighbourhood of Great Arenig (Arenig Mawr) as the radiant point for a great dispersal of blocks of volcanic rock of a characteristic Welsh type. " Ireland. — A brief reference must be made to Ireland, as the ice which took origin there played an important part in bringing about some strange effects in English glaciation, which would be inexplicable without a recog- nition of the causes in operation across the Irish Sea. Ireland is a great basin, surrounded by an almost contin- uous girdle of hills. The rainfall is excessive, and the snowfall was probably more than proportionately great ; 11 144 MAN. AND THE GLACIAL PERIOD. therefore we might expect that an ice-sheet of very large dimensions would result from this combination of fa- vouring conditions. The Irish ice-sheet appears to have moved outward from about the centre of the island, but the main flow was probably concentrated through the gaps in the encircling mountains. " Oalloway. — The great range of granite mountains in the southwestern corner of Scotland seems to have given origin to an immense mass of ice which moved in the main to the southward, and there are good grounds for the belief that the whole ice-drainage of the area, even that which gathered on the northern side of the water-shed, ultimately found its way into the Irish Sea basin and came down coastwise and across the low grounds of the Einns of Galloway, being pushed down by the press of Highland ice which entered the Firth of Clyde, It is a noteworthy fact that marine shells occur in the drift in the course taken by the ice coming on to the extremity of Galloway from the Clyde. " The Lake District. — A radial flow of ice took place down the valleys from about the centre of the Cumbrian hill-plexus, but movement to the eastward was at first for- bidden by the great rampart of the Cross Pell escarpment, which stretches like a wall along the eastern side of the Vale of Eden. "During the time when the Cumbrian glaciers had unobstructed access to the Solway Frith, to the Irish Sea, and to Morecambe Bay, the dispersal of boulders of char- acteristic local rocks would follow the ordinary drainage- lines ; but, as will be shown later, a state of affairs super- vened in the Irish Sea which resulted, in many cases, in a complete reversal of the ice-flow. " The Pennine Chain was the source of glaciers of ma- jestic dimensions upon both its flanks in the region north of Skipton, but to the southward of that breach in the chain (see map) no evidence is obtainable of any local glaciers. ANCIENT GLACIERS IN EASTERN HEMISPHERE. 145 " The Confluent Glaciers. " With the growth of ice-caps upon the great centres a condition of affairs was brought about in the Irish Sea productive of results which will readily be foreseen. The enormous volumes of ice poured into the shallow sea from north, south, east, and west, resulted in such a con- gestion as to necessitate the initiation of some new systems of drainage. " The Irish Sea Glacier. — The ice from Galloway, Cum- bria, and Ireland became confluent, forming what the late Professor Carvill Lewis termed ' the Irish Sea Glacier,' and took a direction to the southward. Here it came in diametrical conflict with the northward-flowing element of the Welsh sheet, which it arrested and mastered ; and the Irish Sea Glacier bifurcated, probably close upon the precipitous Welsh coast to the eastward of the Little Orme's Head, and the two branches flowed coastwise to eastward and westward, keeping near the shore-line. " The westerly branch swept round close to the coast in a southwesterly direction, and completely overrode Anglesea ; striating the rock-surfaces from northeast to southwest (see map), and strewing the country with its bottom-mo- raine, containing characteristic northern rocks, such as the Galloway granites, the lavas and granites of the central and western portions of the Lake District, and fragments of shells derived from shell-banks in the Irish Sea. One epi- sode of this phase of the ice-movement was the invasion of the flrst line of hills between the Menai Straits and Snowdon. The gravels and sands of Fridd-bryn-mawr, Moel Tryfaen, and Moel-y-Cilgwyn, are the coarser wash- ings of the bottom-moraine, and consequently contain such rock-fragments and shells as characterise it. From Moel- y-Cilgwyn southward, evidence is lacking regarding the course taken by the glacier, but it probably passed over or between the Eivals Mountains (Yr Eifl), and down 146 MAN AND THE GLACIAL PERIOD. Cardigan Bay at some distance from the coast in conflu- ence with the ice from mid-Wales ; and, as I have sug- gested, may have passed over St. David's Head. " Eeturning now towards the head of the glacier we may follow with advantage its left bank downward. The ice- flow on the Cumberland coast appears to have resembled very much that in North Wales. A great press of ice from the northward (Galloway) seems to have had a pow- erful ' easting ' imparted to it by the conjoint influences of the thrust of the Irish ice and the inflow of ice from the Clyde. Whatever may have been the cause, the effect is clear : about Kavenglass cleavage took place, and a flow to northward and to southward, each bending easterly. ' By far the larger mass took a southerly course and bent round Black Combe, over Walney, and a strip of the main- land about Barrow in Furness, and out into and across Morecambe Bay. Its limits are marked in the field by the occurrence of the same rocks which characterise it in Anglesea, viz., the granites of Galloway and of west and central Cumbria. " The continued thrust shouldered in the glacier upon the mainland of Lancashire, but the precise point of emergence has not yet been traced, though it cannot be more than a few miles from the position indicated on the map. I should here remark, that all along the bounda- ries the Irish Sea Glacier was confluent with local ice, except, probably, in that part of the Pennine chain to the southward of Skipton. Down to Skipton there was a great mass of Pennine ice which was compelled to take an almost due southerly course, and thus to run directly athwart the direction of the main hills and valleys. A sharp easterly inflection of the Irish Sea Glacier carried it up the valley of the Kibble, and thence, under the shoul- der of Pendle, to Burnley, where Scottish granites are found in the boulder-clay. " On the summit of the Pennine water-shed, at Heald ANCIENT GLACIERS IN EASTERN HEMISPHERE. I4.Y Moor, near Todmorden (1,419 feet), boulder-clay has been found containing erratics belonging to this dispersion; while in the gorge of the Yorkshire Calder, which fl.ows along the eastern side of the same hill, not a vestige of such a deposit is to be found, saving a few erratic pebbles at a distance of eight or ten miles, which were probably carried down by flood- wash from the edge of the ice. " From this point the limits of the ice may be traced along the flanks of the Pennine chain at an average alti- tude of about 1,100 feet. " At one place the erratics can be traced to a position which would indicate the formation of an extra-morainic lake having its head at a col about 1,000 feet above sea- level, separating it from the valley of an eastward flow- ing stream, the Wye, about twelve miles down which a few granite blocks have been found. Other extra-morainic lakes must have been formed, but very little information has been collected regarding them. The Irish Sea Glacier can be shown to have spread across the whole country to the westward of the line I have traced, and beyond the estuary of the Dee. " I may now follow its boundaries on the Welsh coast, and pursue the line to the final melting-place of the glacier. Prom the Little Orme's Head the line of confluence with the native ice is pretty clearly defined. It runs in, per- haps, half a mile from the shore, until the broad low tract of the Vale of Clwyd is reached. Here the northern ice obtained a more complete mastery, and pushed in even as far as Denbigh. This extreme limit was probably at- tained as a mere temporary episode. Horizontal striae on a vertical face of limestone on the crags dominating the mouth of the vale on the eastern side attest beyond dis- pute the action of a mass of land-ice moving in from the north. " I may here remark, that in this district the deposits furnish a very complete record of the events of the Glacial 148 MAN AND THE GLACIAL PERIOD. period. In the cliffs on the eastern side of the Little Orme's Head, and at several other points along the coast towards the east, a sequence may be observed as follows : " 4. Boulder-clay with northern erratics and shells. " 3. Sands and gravels with northern erratics and shells, " 3. Boulder-clay with northern erratics and shells. " 1. Boulder-clay with Welsh erratics and no shells. "A similar succession is to be seen in the Vale of Clwyd. The interpretation is clear : In the early stages of glaciation the Welsh ice spread without hindrance to, and laid down, bed No. 1 ; then the northern ice came down, bringing its typical erratics and the scourings of the sea-bottom, and laid down the variable series of clays, sands, and gravels which constitute Nos. 3, 3, and 4 of the section. " In the Vale of Clwyd an additional interest is imparted to the study of the drift from the circumstance that the remains of man have been found in deposits in caves sealed with drift-beds. The best example is the Cae Gwyn caves, Fig. 42.— The Cefn Cave, in Vale of Clwyd. (Trimmer.) a, Entrance ; ft, mud with pebbles and wood covered with stalagmite ; c, mud, bones, and angular fragments of limestone ; d, sand and silt, with fragments of marine shells ; e. Assure ; /, northern drift ; g, cave cleared of mud j h, river Elwy, 100 feet below ; i, limeBtone rock. in which flint implements and the bones and teeth of va- rious extinct animals were found embedded in 'cave- ANCIENT GLACIERS IN EASTERN HEMISPHERE. 149 earth' which was OTerlaid by bedded deposits of shell- bearing drift, with erratics of the northern type. " It has been supposed that the drift-deposits were ma- rine accumulations ; but it is inconceivable that the cave could ever have been subjected to wave-action without the complete scouring out of its contents. " To resume the delineation of the limits of the great Irish Sea Glacier : From the Vale of Olwyd the boundary runs along the range of hills parallel to the estuary of the Dee at an altitude of about nine hundred feet. As it is traced to the southeast' it gradually rises, until at Frond eg, a few miles to the northward of the embouchure of the "Vale of Llangollen, it is at a height of 1,450 feet above sea-level. Thence it falls to 1,150 feet at Gloppa, three miles to the westward of Oswestry, and this is the most southerly point to which it has been definitely traced on the Welsh border, though scattered boulders of northern rocks are known to occur at Church Stretton. " Along the line from the Vale of Clwyd to Oswestry the boundary is marked by a very striking series of moraine- mounds. They occur on the extreme summits of lofty hills in a country generally almost drif tless, and their ap- pearance is so unusual that one — Moel-y-crio — at least has been mistaken for an artificial tumulus. The limitation of the dispersal of northern erratics by these mounds is very clear and sharp ; and Mackintosh, in describing those at Frondeg, remarked that, while no northern rocks ex- tended to the westward of them, so no Welsh erratics could be found to cross the line to the eastward. There are Welsh erratics in the low grounds of Cheshire and Shrop- shire, but their distribution is sporadic, and will be ex- plained in a subsequent section. " Having thus followed around the edges of this glacier, it remains to describe its termination. It is clear that the ice must have forced its way over the low water-shed between the respective basins of the Dee and the Severn. 150 MAN AND THE GLACIAL PERIOD. So soon as this ridge (less than 500 feet above the sea) is crossed, we find the deposits laid down by the glacier change their character, and sands and gravels attain a great predominance.* Near Bridgenorth, and at other places, hills composed of such materials attain an altitude of 200 feet. Prom Shrewsbury via Burton, and thence, in a semicircular sweep, through Bridgenorth and Enville, there is an immense concentration of boulders and peb- bles, such as to justify the designation of a terminal mo- raine. To the southward, down the valley of the Severn, existing information points to the occurrence merely of such scattered pebbles as might have been carried down by floods. In the district lying outside this moraine there is a most interesting series of glacial deposits and of bould- ers of an entirely different character. (See map.) " From the neighbourhood of Lichfield, through some of the suburbs of Birmingham, and over Frankley Hill and the Lickey Hills to Bromsgrove, there is a great accumu- lation of Welsh erratics, from the neighbourhood, prob- ably, of Arenig Mawr. " The late Professor Carvill Lewis suggested that these Arenig rocks might have been derived from some adjacent outcrop of Palseozoic rocks — a suggestion having its justi- fication in the discoveries that had been made of Cum- brian rocks in the Midlands. To test the matter, an ex- cavation was made at a point selected on Prankley Hill, and a genuine boulder-clay was found, containing erratics of the same type as those found upon the surface. " The explanation has since been offered that this bould- er-clay was a marine deposit laid down during a period of submergence, f Apart from the difficulty that the boulder-clay displays none of the ordinary characteristics of a marine deposition, but possesses a structure, or rather " Mackintosh, Q. J. G. S. f Proceedings of the Birmingham Philosophical Society, vol. vi, Part I, p. 181. ANCIENT GLACIEKS IN EASTERN HEMISPHERE. 151 absence of structure, in many respects quite inconsistent with such an origin, and contains no shells or other remains of marine creatures, it must be pointed out that no theory of marine flotation will explain the distribution of the erratics, and especially their concentration in such num- bers at a station sixty or seventy miles from their source. " Upon the land-ice hypothesis this difficulty disappears. During the early stages of the Glacial period the Welsh ice had the whole of the Seyern Valley at its mercy, and a great glacier was thrust down from Arenig, or some other point in central Wales, having an initial direction, broadly speaking, from west to east. This glacier extended across the valley of the Severn, sweeping past the Wrekin, whence it carried blocks of the very characteristic rocks to be lodged as boulders near Lichfield ; and it probably formed its terminal moraine along the line indicated. (See lozenge- shaped marks on the map.) As the ice in the north gath- ered volume it produced the great Irish Sea Glacier, which pressed inland and down the Vale of Severn in the manner I have described, and brushed the relatively small Welsh stream out of its path, and laid down its own terminal moraine in the space between the Welsh border and the Lickey Hills. It seems probable that the Welsh stream came mainly down the Vale of Llangollen, and thence to the Lickey Hills. Boulders of Welsh rocks occur in the intervening tract by ones and twos, with occasional large clusters, the preservation of any more connected trail being rendered impossible by the great discharge of water from the front of the Irish Sea Glacier, and the distrib- uting action of the glacier itself. " Within the area in England and Wales covered by the Irish Sea Glacier all the phenomena point to the action of land-ice, with the inevitable concomitants of sub-glacial streams, extra-morainic lakes, etc. There is nothing to suggest marine conditions in any form except the occur- rence of shells or shell fragments ; and these present so 152 MAN AND THE GLACIAL PERIOD. many features of association, condition, and position in- consistent with what we should be led to expect from a study of recent marine life, that conchologists are unani- mous in declaring that not one single group of them is on the site whereon the shells lived. It is a most significant f act^one out of a hundred which could be cited did space permit — that in the ten thousand square miles' of, as it is supposed, recently elevated sea-bottom, not a single ex- ample of a bivalve shell with its valves in apposition has ever been found ! Nor has a boulder or other stone been found encrusted with those ubiquitous marine parasites, the barnacles. " The evidences of the action of land-ice within the area are everywhere apparent in the constancy of direction of — (1.) Striae upon rook surfaces. (3.) The terminal curva- ture of rocks. (3.) The ' pull-over ' of soft rocks. (4.) The transportal of local boulders. (5.) The orientation of the long axes of large boulders. (6.) The false bedding of sands and gravels. (7.) The elongation of drift-hills. (8.) The relations of ' crag and tail.' There is a similar general constancy, too, in the directions of the striae upon large boulders. Upon the under side they run longitudi- nally from southeast (or thereabouts) to northwest, while upon the upper surface they originate at the opposite end, showing that the scratches on the under side were produced by the stone being dragged from northwest to southeast, while those on the top were the product of the passage of stone-laden ice over it in the same direc- tion. " Such an agreement cannot be fortuitous, but must be attributed to the operation of some agent acting in close parallelism over the whole area. To attribute such regu- larity to the action of marine currents is to ignore the most elementary principles of marine hydrology. Ice- bergs must, in the nature of things, be the most erratic of all agents, for the direction of drift is determined — ANCIENT GLACIERS IN EASTERN HEMISPHERE. 153 among other varying factors — by the draught of the berg. A mass of small draught will be carried by surface cur- rents, while one of greater depth will be brought within the influence of under-currents ; and hence it not infre- quently happens that while floe-ice is drifting, say, to the southeast, giant bergs will go crashing through it to the northwest. There are tidal influences also to be reckoned with, and it is nlatter of common knowledge that flotsam and jetsam travel back and forth, as they are alternately affected by ebb and flood tide. " Bearing these facts in mind, it is surely too much to expect that marine ice should transport boulders (how it picked up many of them also requires explanation) with such unfailing regularity that it can be said without chal- lenge,* ' boulders in this district [South Lancashire and Cheshire] never occur to the north or west of the parent rock.' The same rule applies without a single authentic exception to the whole area covered by the eastern branch of the Irish Sea Glacier ; and hence it comes about that not a single boulder of Welsh rock has ever been 1 ecorded from Lancashire. " The Solway Glacier. — The pressure which forced much of the Irish Sea ice against the Cumbrian coast-line caused, as has been described, a cleavage of the flow near Ravenglass, and, having followed the southerly branch to its termination in the midlands, the remaining moiety de- mands attention. " The ' easting ' motion carried it up the Solway Frith, its right flank spreading over the low plain of northern Cumberland, which it strewed with boulders of the well- known ' syenite ' (granophyre) of Buttermere. When this ice reached the foot of the Cross Fell escarpment, it suf- fered a second bifurcation, one branch pushing to the eastward up the valley of the Irthing and over into Tyne- * Brit. Assoc. Report, 1890, p. 343. 154 Man and the glacial period. side, and the other turning nearly due southward and forcing its way up the broad Vale of Eden. " Under the pressure of an enormous head of ice, this stream rose from sea-level, turned back or incorporated the native Cumbrian Glacier which stood in its path, and, having arrived almost at the water-shed between the northern and the southern drainage, it swept round to the eastward and crossed over the Pennine water-shed; not, however, by the lowest pass, which is only some 1,400 feet above sea-level, but by the higher pass of Stainmoor, at altitudes ranging from 1,800 to 2,000 feet. The lower part of the course of this ice-flow is sufiBciently well char- acterised by boulders of the granite of the neighbourhood of Dalbeattie in Galloway ; but on its way up the Vale of Eden it gathered several very remarkable rocks and posted them as way-stones to mark its course. One of these rocks, the Permian Brockram, occurs nowhere in situ at altitudes exceeding 700 feet, yet in the course of its short transit it was lifted about a thousand feet above its source. The Shap granite (see radiant point on map) is on the northern side of the east and west water-sheds of the Lake District, and reaches its extreme elevation, (1,656 feet) on Wasdale Pike; yet boulders of it were carried over Stainmoor, at an altitude of 1,800 feet liter- ally by tens of thousands. " This Stainmoor Glacier passed directly over the Pen- nine chain, past the mouths of several valleys, and into Teesdale, which it descended and spread out in the low grounds beyond. Pursuing its easterly course, it abutted upon the lofty Cleveland Hills and separated into two streams, one of which went straight out to sea at Hartle- pool, while the other turned to the southward and flowed down the Vale of York, being augmented on its way by tributary glaciers coming down Wensleydale. The final melting seems to have taken place somewhere a little to the southward of York ; but boulders of Shap granite by ANCIENT GLACIERS IN EASTERN HEMISPHERE. 155 which its extension is characterised have been found as far to the southward as Koyston, near Barnsley. " The other branch of the Solway Glacier — that which travelled due eastward — passed up the valley of the Ir- thing, and over into that of the Tyne, and out to sea at Tynemouth. It carried the Scottish granites with it, and tributary masses joined on either hand, bringing charac- teristic boulders with them. " The fate of those elements of the Solway Frith Gla- cier which reached the sea is not left entirely to conject- ure. The striated surfaces near the coast of Northum- berland indicate a coastwise flow of ice from the north- ward — ^probably from the Frith of Forth — and the gla- ciers coming out from the Tyne and Tees were deflected to the southward. " There is conclusive evidence that this ice rasped the cliffs of the Yorkshire coast and pressed up into some of the valleys. Where it passed the mouth of the Tees near Whitby it must have had a height of at least 800 feet, but farther down the coast it diminished in thickness. It nowhere extended inland more than a mile or two, and for the most part kept strictly to the coast-line. Along the whole coast are scattered erratics derived from Gal- loway and the places lying in the paths of the glaciers. In many places the cliffs exhibit signs of rough usage, the rocks being crumpled and distorted by the violent impact of the ice. At Filey Brigg a well-scratched sur- face has been discovered, the striation being from a few degrees east of north. " At Speeton the evidence of ice-sheet or glacier- work is of the most striking character. On the top of the cliffs of Cretaceous strata a line of moraine-hills has been laid down, extending in wonderful perfection for a distance of six miles. They consist of a mixture of sand, gravel, and a species of clay-rubble, with occasional masses of true bould- er-clay, the whole showing the arched bedding so char- 156 MAN AND THE GLACIAL PERIOD. acteristic of such accumulations. At the northerly end the moraine keeps close to the edge of the chalk clifEs, which are there 400 feet high, and the hills are frequently displayed in section ; but as the elevation of the cliffs de- clines they fall back from the edge of the cliffs and run quite across the headland of Plamborough, and are again 13 6PEeT0N CLIFFS JM BUCKTON OLfFFS Jg N BEMPTON CLIFFS H r (fimtortti»u.in chaSi^ -^CalNab . fy,f. BanwicJe 10 1 ^'^^ - ~. North Sea Landing M H(V " 8 r,BrailMead 'Uso ^StattJfBank g *^^«J 14 ^<^iHigli, Sfcuika I 1^ J^*^JtE hAIflOff Fig. 43.— Moraine between Speeton and Plamborongh (Lamplngh). exposed in section in Bridlington Bay. One remarkable and significant fact is pointed out, namely, that behind this moraine, within half a mile and at a lower level, the country is almost absolutely devoid of any drift whatever. "The interpretation of these phenomena is as follows; ANCIENT GLACIERS IN EASTERN HEMISPHERE. 157 When the valley-glaciers reached the sea they suffered the deflection which has been mentioned, partly as the result of the interference of ice from the east of Scotland, but also influenced directly by the cause which operated upon the Scottish ice and gave direction to it— that is, the im- pact of a great glacier from Scandinavia, which almost filled the North Sea, and turned in the eastward-flowing ice upon the British coast. " It is easy to see how this pressure must have forced the glacier-ice against the Yorkshire coast, but vertical chalk cliffs 400 feet in height are nob readily surmounted by ice of any thickness, however great, and so it coasted along and discharged its lateral moraine upon the cliff-tops. As the cliffs diminished in height we find the moraine farther inland, and, as I have pointed out, the ice completely over- rode Flamborough Head. Amongst the boulders at Flam- borough are many of Shap granite, a few Galloway gran- ites, a profusion of Carboniferous rocks, brought by the Tyne branch of the Solway Glacier as well as by that of Stainmoor, and, besides many torn from the cliffs of York- shire, a few examples of unquestionable Scandinavian rocks, such as the well-known Rhomhen-porphyr. It is impor- tant to note that about ten to twenty miles from the York- shire coast there is a tract of sea-bottom called by trawl- ers ' the rough ground,' in allusion to the fact that it is strewn with large boulders, amongst which are many of Shap granite. This probably represents a moraine of the Teesdale Glacier, laid down at a time when the Scandi- navian Glacier was not at its greatest development. " On the south side of Flamborough Head the ' buried cliff ' previously alluded to occurs. The configuration of the country shows — and the conclusion is established by numerous deep-borings — that the pre-glacial coast-line takes a great sweep inland from here, and that the plain of Holderness is the result of the banking-up of an im- mense thickness of glacial deiris. In the whole country 158 MAN AND THE GLACIAL PERIOD. reviewed, from Tynemouth to Bridlington, wherever the ice came on to the land from the seaward, it brought in shells and fragmentary patches of the sea-bottom in- volved in its ground moraine. Space does not permit of a detailed description of the several members of the York- shire Drift, and I pass on to deal in a general way with the glacial phenomena of the eastern side of Eng- land. " The East Anglian Glacier. — The influence of the Scandinavian ice is clearly seen in the fact that the entire ice-movement down the east coast south of Bridlington .was all from the seaward. Clays, sands, and gravels, the products of a continuous mass of land-ice coming from the northeast are spread over the whole country, from the Trent to the high grounds on the north of London over- looking the Thames. " The line of extreme extension of these drift-deposits runs from Pinchley (near London), in the south across Hertfordshire, through Cambridgeshire, with outlying patches at Grogmagog and near Buckingham, and north- westward over a large portion of Leicestershire into the upper waters of the Trent, embracing the elevated region of PalsBozoic rocks at Oharnwood Forest, near Leices- ter. " Reserving the consideration of the very involved ques- tions connected with the drifts of the upper part of the Trent Valley, I may pass on to Join the phenomena of the southeastern counties with those at Plamborough Head. Prom Nottinghamshire the limits of the drift of the East Anglian Glacier seem to run in a direction nearly due west to east, for the great oolitic escarpment upon which Lincoln Cathedral is built is absolutely driftless to the northward of the breach about Sleaford. However, along the western flank of the oolitic range true boulder-clay occurs, bordering and doubtless underlying the great fen- tract of mid-Lincolnshire; and the great Lincolnshire ANCIENT GLACIERS IN EASTERN HEMISPHERE. 159 ■ Wolds appear to have been completely whelmed beneath the ice. " The most remarkable of the deposits in this area is the Great Chalky Boulder-Clay, which consists of clay con- taining much ground-up chalk, and literally packed with well-striated boulders of chalk of all sizes, from minute pebbles up to blocks a foot or more in diameter. Associ- ated with them are boulders of various foreign rocks, and many flints in a remarkably fresh condition, and still re- taining the characteristic white coat, except where par- tially removed by glacial attrition. " One of the perplexing features of the glacial phenom- ena in the eastern counties of England is the extension of true chalky boulder-clay to the north London heights at Pinchley and elsewhere ; for only the faintest traces are to be found in the gravel deposits of the Thames Valley of any wash from such a deposit, or from a glacier carry- ing such materials. " It has been suggested that the deposit may have been laid down in an extra-morainic lake, or in an extension of the North Sea, but these suggestions leave the difficulty just where it was. If a lake or sea could exist without shores, a glacier-stream might equally dispense with banks. Within the area of glaciation, defined above, abundant evidence of the action of land-ice is obtainable, though striated surfaces are extremely rare — a fact attributable to the softness of the chalk and clays which occupy almost the whole area. Well-striated surfaces are found on the harder rocks, as, for example, on the oolitic limestone at Dunston, near Lincoln. "Mr. Skertchly has remarked that the proofs of the action of land-ice are irrefragable. The Great Chalky Boulder-Clay covers an area of 3,000 square miles, and at- tains an altitude of 500 feet above the sea-level, thus be- speaking, if the product of icebergs, ' an extensive gath- ering-ground of chalk, having an elevation of more than 12 160 MAN AND THE GLACIAL PERIOD. ANCIENT GLACIERS IN EASTERN HEMISPHERE. 161 500 feet. But where is it ? Certainly not in Western Europe, for the chalk does not attain so great an elevation except in a few isolated spots.' * " It has been further pointed out by Mr. Skertchly, that the condition of the flints in this deposit furnishes strong evidence that they could not have been carried by floating ice nor upon a glacier, for, in either of the latter events, there must have been some exposure to the weather, which, as he remarks, would have rendered them worthless to the makers of gun-flints, whereas they are now regularly col- lected for their use. " The way in which the boulder-clay is related to the rocks upon which it rests is a conclusive condemnation of any theory of floating ice ; for example, where it rests up- on Oxford Clay, it contains the fossils characteristic of that formation, as it is largely made up of the clay itself. The exceptions to this rule are as suggestive as those cases which conform to it. Each outcrop yields material to the boulder-clay to the southwestward, showing a pull-over from the northeast. " One of the most remarkable features of the drift of this part of England is the inclusion of gigantic masses of rock transported for a short distance from their native outcrop, very often with so small a disturbance that they have been mapped as in sihi. Examples of chalk-masses 800 feet in length, and of considerable breadth and thick- ness, have been observed in the cliffs near Cromer, in Nor- folk, but they are by no means restricted to situations near the coast. One example is mentioned in which quarrying operations had been carried on for some years before any suspicion was aroused that it was merely an erratic. The huge boulders were probably dislodged from the parent rock by the thrust of a great glacier, which flrst crumbled the beds, then sheared off a prominent fold and * tieikie's Great loe Age, p. 360. 162 MAN AND THE GLACIAL PERIOD. " "n-t « pq flO- ing in connection with sharp sxibstances, like fractured flints, or else as having been made by the teeth of sharks, whose fossil remains are found in great abundance in the same formation. All the discoveries of flints supposed to show traces of intentional chipping are pronounced to be unsatisfactory, with the exception of those found in three localities — The- nay (near Tours) and Puy-Coumy (near Aurillac), in France, and Otta, in the valley of the Tagus, in Portugal. As European archaeologists at the present time are substan- tially in accord with Mortillet in restricting the discussion to these three places, I will follow their example. But al- though Mortillet believes that flints found at all these locali- ties exhibit marks of intelligent action, he will not admit that they are the work of man. He attributes them to an intelligent ancestor of man, whom he calls by the name of anthropopithecus, or the precursor of man. Of this creat- ure he distinguishes three different species, named respect- ively after the discoverers of the flints in the three localities just mentioned. The precursor, however, has found up to this time only a very limited acceptance among men of science, although a few believe in him on purely theoretical grounds. The discussion generally turns upon the question whether these flints were chipped intentionally or are the result of natural causes ; and also upon the determination of the geological age of the formations in which they are found. I visited Thenay, the most celebrated of these three locali- ties, in 1877, and had the advantage of studying the question there under the guidance of the late Abbe Bourgeois, the dis- coverer of the flints, and one of the most prominent advo- cates of the Tertiary man. This was the year before he died, and he showed me at the time his complete collection, and gave me several of the objects he had discovered. Geolo- gists are agreed in assigning the deposits in which they occur to the lower Miocene or middle Tertiary period, which restricts the discussion to the character of the flints 368 MAN AND THE GLACIAL PERIOD. themselves. The accompanying woodcut * gives some indica- tion of their appearance, although it is misleading, because Fig. 108.— Flint flakes collected by Abb6 Bourgeois from Miocene strata at Thenay (after Gaudry). Natural size. the long figure resembling a flint knife is intended to repre- sent a solid nucleus. None of these objects, however, ought to be called " flints flakes," as very few, if any, flakes show * Prom Le Conte, op. eit., p. 608. The figures are copied from Gaudry, who borrowed them from the article by Bourgeois, Congres Internat. de BruxelUs, 1872, p. 89, pi. ii ; and from his La Question de V Homme Tertiare, Revue des Questions Scientifiques, 1877, p. 15. APPENDIX. 369 ing the " bulb of percussion," always seen upon them, have been discovered in the Tertiary deposits at Thenay,* al- though I have found them there myself upon the surface. The three other figures would be classed by archaeologists as "piercers," as Bourgeois has himself designated them, and are also solid objects. Many of the Thenay flints exhibit a " crackled " appearance, due to the action of heat. On this account Mortillet maintains that they were splintered by fire, and not formed by percussion, the usual method by which flint implements were fabricated in the stone age. The Thenay objects are all of very small dimensions, and are so absolutely unlike the large, rudely-chipped axes of the Chellean type, found in so many different parts of the world, and generally accepted as the implement used by Palaeolithic man, that the question naturally suggests itself. What could have been the purpose for which these little implements were employed ? No better answer has been suggested than the ludicrous one that they were used by the hairy anthropopithecus to rid himself of the vermin with which he was infested. But, leaving aside the question of their purpose, let us consider the evidence presented by the flints themselves. Do they exhibit the unmistakable traces of intentional chip- ping produced by a series of slight blows or thrusts, deliv- ered in regular succession and in the same direction, with the result of forming a distinctly marked edge ? And does the appearance of the action of flre upon their surface imply the intervention of intelligence ? To both questions M. Adrien Arcelin, the well-known geologist of Macon, has given very sufScient replies in the negative. He has discov- ered numerous objects of precisely similar appearance in Eocene deposits in the neighborhood of MS,con.+ But, in- stead of pushing man back on this account so much further into the past, he accounts for the marks of chipping to be seen on many of these objects as the result of the acciden- tal shocks of one stone against another in the countless * Le Prehistorique, p. 91. f Materiaux pour I'Histoire Prim, et Nat. de I'Homme, tome xix, p. 193. 370 I»1AN AND THE GLACIAL PERIOD. overtumings and movements to which, the strata have been subjected during the long ages of geological time. He gives photographs of some of these objects, which are to me en- tirely conviuciug, and describes how he has surprised Nature in the very act of fabricating them ia an abandoned quarry worked in an Eocene deposit. He thinks the " crackled " surfaces can be readily explaiued as the result of atmos- pheric action, or of hot springs charged with silex. Numer- ous examples of similar changes in the surface of flint, that have been noticed by himself and others in di£ferent locali- ties, are instanced. Even if some have been caused by Are, this does not necessarily imply the intervention of man to have produced it. Similar discoveries have also been made by M. d'Ault de Mesnil, at Thenay, in Eocene deposits,* and by M. Paul Oabanne, in the Gironde.t My own opinion, based upon the experience of many years spent in the study of flints broken naturally as well as artificially, and upon a careful examination of Bourgeois's collections, is that the so- called Thenay flints are the result of natural causes. The second locality where flints alleged to display marks of human action have been found is the vicinity of Aurillac, in the Auvergne, especially on the flanks of a hill called Puy-Coumy. They occur in a conglomerate of the upper Miocene period, and are consequently much later than the Thenay flints. In this conglomerate, lq 1869, M. Tardy dis- covered a worked flint flake which has every appearance of being artiflcial. t Mortillet, however, says that it was found in the upper surface of the deposit, where there may easily have been a mingling with the Quaternary formation ; and it certainly resembles worked flakes, which are not uncommon in the Quaternary. The geological determination of the find may consequently be regarded as uncertain. The flints discovered at Puy-Courny by M. Eames are of small dimensions, and have all been produced by percussion. Many of them are said to bear some resemblance to pointed * Materiaux, ibid., p. 246. f Id., tome xxii, p. 205. I See Materiaux, tome vi, p. 94. S. Reinaoh, however. Descrip- tion liaison, du Musee de Saint-Germain-en-Laye, i, p. 107, n. 8, calls it " gravure inexacte." AFfEJNDlX. 371 flakes of artificial origin, and one has been figured, probably- selected for its excellence.* It is by no means convincing to me, and I am not at all surprised that so many archaeologists question the artificial character of these objects, which ex- hibit a great variety of forms. Upon this point Eames does not profess to be qualified to pronounce judgment, limiting himself solely to the geological questions. He argues, how- ever, that the fact that all the objects supposed to be arti- ficial are made of the best qualities of flint, of which imple- ments are ordinarily made, although fragments of inferior quality are abundant in the same formation, implies the in- tervention of man's judgment in making the selection. But M. Boule shows that this is merely the result of the erosion of an ancient river, which operated only upon the upper beds, in which alone the better qualities of flint are to be found ; and Rames has accepted this explanation.! The flints of Puy-Coumy seem to fall within the same category as those of Thenay. They are the product of denudation, have travelled long distances, and have been subjected to the action of powerful agents. These causes are sufiicient to account for the shocks of which they show the traces, and to explain the production of splinters arising therefrom. The last locality in which flints claimed to have been manufactured by the Tertiary man are supposed to have been discovered is the so-called desert of Otta, in the valley of the Tagus, not far from Lisbon. The formation there is a lacustrine deposit of great thickness, belonging to the upper Miocene, and aboundiug in flint. Here, during the course of twenty years, M. Ei- beiro discovered, but mostly upon the surface, a large num- ber of flakes of flint and quartzite. After much debate in regard to them, ninety-five of them were finally sent by him to Paris, in 1878, and placed in the archaeological de- partment of the great exposition. There they were to be submitted to the judgment of the assembled prehistoric archaeologists of all nationalities, many of whom, including the writer, availed themselves of the opportunity of carefully * Materiaux, tome xviii, p. 400. f Reyue d'Anthropologie (third series), tome iv, p. 317. 372 MAN AND THE GLACIAL PERIOD. studying them. The judgment of Mortillet is that twenty- two specimens exhibited unmistakable traces of intentional chipping, in which opinion I entirely concur. Only nine, however, were represented as coming from the Miocene, some of which showed on their surface an incrustation of grit, which was claimed as proof of their origin. But the opinion was freely expressed that, even if they really came from the Miocene deposits, they might have penetrated into them from the surface, through cracks, and thus have be- come so incrusted. It was accordingly resolved to hold the next international congress of prehistoric archaeologists at Lisbon, ia 1880, mainly for the purpose of settling this ques- tion, if possible, by an investigation conducted upon the spot. In the course of a visit made at that time to Otta, several artificial specimens were found on the surface by different searchers, but Professor Bellucci, of Perugia, was fortunate enough to discover a flint flake in situ, stUl so closely im- bedded in the deposit that it required to be detached by a hammer. There is no question that this object was actually found in a Miocene deposit, but unfortunately it belongs to the doubtful category of external flakes, which, although they exhibit the " bulb of percussion," have no other sure indication that they are the work of man.* As such bulbs can be produced by natural causes, some stronger proof than this of the existence of Tertiary man is demanded. These are all the localities in Europe claimed by Mortillet to have furnished such evidence, but he thinks a strong con- flrmation of it is afforded by certain discoveries made in the auriferous gravels of California. I will not occupy space here in repeating arguments I have brought forwarH else- where to show the utter insufiiciency of this evidence to prove the existence of man on the Pacific coast of our conti- nent during the Pliocene period, t They may all be summed up in the words of Le Conte : " The doubts in regard to this * It has been figured by Bellucci, Archivio per VAnthropologia e la Etnologia di Firenze, tome xi, p. 13, tav. iv, fig. 2. To me it possesses no value as evidence. f The Prehistoric Archaeology of North America, Narrative and Critical History of America, vol. i, pp. 350-356. APPENDIX. 373 extreme antiquity of man are of three kinds, viz. : 1. Doubts as to the Pliocene age of the gravels — they may be early Quaternary. 2. Doubts as to the authenticity of the finds- no scientist having seen any of them in situ. 3. Doubts as to the undisturbed conditions of the gravels, for auriferous gravels are especially liable to disturbance. The character of the implements said to have been found gives peculiar emphasis to this last doubt, for they are not Palaeolithic, but Neolithic.'''' * The question has been raised whether this archaeological objection is applicable to the stone mortars, numerous examples of which have been found in the gravels, some of them quite recently.f If the evidence brought for- ward by Professor Whitney and others were limited to these mortars, it might very well be claimed that they are neither Palaeolithic nor Neolithic ; that the smoothness of their surface is owing to their having been hollowed out of pebbles that have been polished and worn by natural forces. But Professor Whitney has cited numberless instances of "spear-heads," "arrow-heads," "discoidal stones," "stone beads," and " a hatchet " that have been found under pre- cisely similar conditions as the mortars. So Mr. Becker has recently produced an afiidavit of a certain Mr. Neale that in a tunnel run into the gravel in 1877 " between two hun- dred and three hundred feet beyond the edge of the solid lava, he saw several spear-heads nearly one foot in length." % Now it cannot be questioned that such objects as these clearly belong to the Neolithic period, which does not imply that all the objects used at that time were polished, but that together with chipped implements " polished stone implements were also used."* No archaeologist will believe that, while Pa- laeolithic man has not yet been discovered in the Tertiary deposits of western Europe, the works of Neolithic man have * Le Conte, op. cit., p. 614. f Professor George Frederick Wright, Prehistoric Man on the Pacific Coast, Atlantic Monthly, April, 1891, p. 513 ; Table Mownt- ain ArchoBology, Nation, May 31, 1891, p. 419. X Antiquities from wnder Tuolome Table Mountain in California, Bulletin of the Geological Society of America, vol. ii, p. 193. * Le Conte, op. cit, p. 607. 374 MAN AND THE GLACIAL PEEIOD. been found in similar deposits in western America. Peculiar difficulties seem to surround the evidence brought forward in support of such an assumption. We are told by Professor Whitney that a stone mortar was " found standing upright, and the pestle was in it, in its proper place, just as it had been left by the owner." He fails, however, to explain how this was brought about in a gravel deposit supposed to have been laid down by great floods of water. So, when Mr. Neale swears that he saw fifteen years ago in the same gravels spear-heads a great deal larger than those known to archaeologists, may we not ask whether reliance can be placed on the memory of witnesses who testify to impossi- bilities to justify conclusions that rest upon such testimony ? I think we shall have to wait for further and better evi- dence than this before we are called upon to admit that the existence of the Tertiary man upon our Pacific coast has been established. INDEX. Aar Glacier, 11, 43, 132. Abbeville, France, 251, 263. Abbott, C. C, cited, 242, 245. Adams, Charles Francis, cited, 297. Adh^mar, cited, 307, 310. Africa, ancient glaciers of, 191. Agassiz, Louis, cited, 9, 11, 43, 128, 241. Ailsa Cr£^, 167, 168. Akron, Ohio, 220, 221. Alaska, 1, 22, 23 et seq., 47, 212, 283 ; climate of, 291, 302. Aletsch Glacier, 9, 211, 241. Alleghany Valley, 206, 214 ; ten-aces in, 229. Alpine glaciers, existing, 9-11, 43 et seq, ; size and number of, 9 ; depth of, 11 ; velocity of, 43 et seq. ; an- cient, 58-60, 131-136 ; advance and retreat of, 116. Alps, 1, 9-11, 43 et seq., 58 et seq., 91, 131 et seq., 211 ; age of, 328. Altaville, Cal., 296. Amazon Valley, temperature of, 316. Amherst, Ohio, glacial marks near, 52. Amiens, France, implements from, 252, 263 et seq. ; terraces at, 360. Andes, 17, 330 ; age of, 328. Andover, Mass., 77 et seq., 345. Andrews, cited, 845, 347, 354, 356. Animals, extinct, associated with man in eastern America, 262 ; in France, 263 ; in England, 264 et seq.; in Wales, 272; in Belgium, 277 et seq. ; summary concerning, Z81-293. Animals, relics of, in loess, 188. Antarctic Continent, existing gla- ciers of, 1, 18 et seq. Arcy, Belgium^grotto at, 279. Areni^ Mawr, wales, 150, 151, 172. Argillite implement, face and side view of, 247, 259. Arnhem, Holland, moraine at, 181. Asia, existing glaciers in, 14 et seq. ; ancient glaciers of, 190. Assiniboine River, 228. Astronomical theories of the Glacial period, 303 et seq. Atlantic Ocean, 314. Aurillac, supposed flint-chips near, 367, 370. Australia, ancient glaciers of, 126, 192. Austria, existing glaciers of, 9. Auvei'gne, 136. Babbitt, Miss F. E., cited, 253, 254, 255. Bakewell on age of Niagara gorge, 337 Baldwin, C. C, 251. Baldwin, P., 25. Ball, cited, 310, 317. Baltic Sea, 129. Barnsley, England, 155. Bates, cited, 204. Bear, 270, 287, 290. Bear, grizzly, 270, 288. Beaver, 289. Beaver Creek, Pa., 205, 230, 232. Becker, cited, 296, 300, 349. Bedford, England, 265. Beech Flats, Ohio, terrace at, 217. Belgium, human relies in glacial terraces in, 264 ; caverns of, 274. Bell, cited, 109, 117 ; on unity of the Glacial period, 110. Bellevue, Pa., glacial terrace on the Ohio at, 217. Bellucci, cited, 372. Ben Nevis, 240. Bernese Oberland, 9, 59, 131, 132. Big Stone Lake, 208, 226. Birmingham, England, 150. Bishop, cited, 306. Bison, 262, 270, 271, 278, 289. 376 MAN AND THE GLACIAL PERIOD. Black Forest, the, 136. Black Eiver, OMo, 343. Black Sea, 238. Blanc, Mont, 1, 9-11, 132, 211. Blandford, cited, 312. Boone County, Ky., glacial deposits in, 212. Boston, scratched stone from till of, 54 ; drumlins in the vicinity of, 75. Boston Society of Natural History, 296. ■ Boulder-clay. (See Till.) Boulders, disintegrated, 57, 71. Boulders, distribution of, in New England, 57, 60, 61, 69 et seq. ; in - Switzerland, 58 et seq., 133. Boulders, transportation of, in Penn- sylvania, 57, 61, 85 ; in New Hamp- shire, 60, 71 ; in Kentucky, 63, 97 ; in Ohio, 64, 72 ■ in Rhode Island, 67 ; in MassachusettB, 69 et seq. ; in Connecticut, 71, 72 ; in New Jersey, 83 ; in Illinois, 97. Bourgeois, Abb6, cited, 367. Bridgenorth, England, 150. BridPmgton, England, 156, 158. Bristol Channel, 138, 178. British Columbia, 1, 23, 121 et seq., 194. 198. British Isles, ancient glaoiei-s of, 186- 181 ; preglacial level of land in, 139-141; preglacial climate in 141, 142 ; great glaoial centres — Wales, 143 ; Ireland, 143 ; Galloway, 144 ; Lake District, 144 ; Pennine Chain, 144 ; confluent glaciere — Irish Sea Glacier, 145-153 ; Solway Glacier, 153-158; East Anglian Glacier, 158 ; Isle of Man, 164^167 ; the so- called Great Submergence, 167- 180 ; dispersion of erratics or Shap granite, 180, 181 ; drainage of, 238 ; caverns of, 267 ; climate of, 314. Brixham Cave, 267 et seq. Bromsgrove, England, 150. Brooklyn, N. Y., 66, 67. Brown, on glaciers of Greenland, 40, 41. Brown's Valley, 226. Bruce, skull of, 276. Buried forests in America, 107 et seq. Buried outlets and channels, 199- 210 ; of Lake Erie, 201, 333 ; of Lake Huron, 202 ; of Lake Onta- rio, 202 ; of Lake Superior, 203 ; of Lake Michigan, 203 , in south- western Ohio, 203 ; near Cincin- nati, 203; near Louisville, Ky., 205 ; in the Tuscarawas Valley, 205 ; in the valley of the Beaver, 205 ; of Oil Creek, 205 ; in the valley of the Alleghany, 206 ; of Chautauqua Lake, 207 ; near Min- neapolis, 208. Burton, England, 164. Busk, cited, 267. Buttermere, England, 153, 168. Cache Valley, Utah, 233. Cae Gwyn Cave, 148, 271 et seq., 280. Caithness, Scotland, 180. Calaveras skull, 295, 300. California, 21, 124, 281, 287, 294, 358, 372. Cambridgeshire, England, 158. Canada, 94, 95. Canstadt, man of, 279. Canton, Ohio, 232. Cape St. Eoque, 313. Caribbean Sea, 318. Caribou, 262. Carll, cited, 205, 207. Carpathian Mountains, 136, 328. Carpenter, F. E., cited, 321, 322. Cascade Range, 21. Caspian Sea, 238. Cattaraugus Creek, N. T., 220. Caucasus Mountains, 15 ; age of, 328. Cave-bear. 269-271, 278, 280 ; hyena, 269, 270, 278 ; lion, 269-271, 278. Caverns, British, 267-274; on the Continent, 274-281. Cefn Cave, 148, 271. Cenis, Mont, 135. Centres of glacial dispersion, 304 et seq., 323 et seq., 328 ; in America, 113, 121 ; in Europe, 129 et seq. ; in the British Isles, 142 et seq. Cevennes, 136. Chamberlin, T. C, terminal moraine of second Glacial epoch, 93, 98 et seq. ; on driftless area, 102, 103 ; cited, 110, 218, 229, 307 ; on Cin- cinnati ice-dam, 218. Chamois, 289, 290. ' Chamouni, 132. Charpentier, 9, 59. Chasseron, 58, 132. Chautauqua Lake, buried outlet of, 207. Chenango Eiver, 220. Cheshire, England, 149, 153, 178, 180. Cheyenne Eiver, 228. Chicago, 111., 346. Chimpanzee, skull of, 276. Chur, 133. Cincinnati, buried channels near, 203 et seq. ; glacial dam at, 212 ei seq. ; terraces at, 231. Clarksburg, W. Va., 216. INDEX. 377 Claymont, Del., 258 et seq. ; view of implement found near, 259. Claypole, cited, 200, 219, 221. Climate of Glacial period, 291. Clwyd, vale of, 147 et seq., 271 et sea. Clyde, the, 144. ^ Collett, cited, 107. Colorado, 123, 124. Columbia deposit, 245, 254 et seq. Columbiana County, Ohio, 232. Comstock, cited, 307. Conewango Creek, 232; ancient depth of, 206. Connecticut, 71, 72, 74, 91. Oonyers, citedj 265. Cook on subsidence in New Jersey, Cope, cited, 288. Cordilleran Glacier, 121 et seq. Corswall, England, 312. Cows, 268. Cresson, cited, 251, 258 et seq. Crevasses. (See Fisshees.) CroU, cited, 304, 807 et seq. ; 832, 362. Cro Magnon, rook shelter of, 281. Cromer, England, 160. Crosby, on composition of till, 81 et seq. Cross Fell escarpment, 153, 180. Culoz, 132. Cumberland, England, 146, 158, 168, 173. Cumming, quoted, 166. Cushing, H., 26 Cuyahoga Elver, 220, 221 ; buried channel of, 200. Dana, Professor J. D., on depth of ice, 91 ; on driftless area, 102 ; cited, 320, 363. Danube, ancient glaciers of the, 129, 134, 188. Darent, valley of, 265. Darrtown, Ohio, 107. Darwin, Charles, cited, 17, 126, 170, 241,361. Darwin, George 6., cited, 361. Darwin, Mrs. M. J., mortar owned by, 297. Date of Glacial period, chapter on, 332-364. Davidson Glacier, 23. Davis on drumlins, 75. Dawkius, cited, 238, 267, 269, 291. Dawson, G. M., cited, 121 ; on ice- movements, 97 ; on oscillation oi land-level, 125, 126. Dawson, Sir William, on the fiord of the Saguenay, 197 ; cited, 285. Dee, the river, 149. Deeley, quoted, 164. Delaware Kiver, 282, 242 et seq., 254, 258 ; section across the, 245. Delta ten-ace at Trenton, N. J., 242 et seq. ; at Beaver, Pa., 230. De Ranee, cited, 272. Derbyshire, England, 270. Desor on age of Niagara gorge, 837. Diore, glaciers of the, 185. Disintegration, amount of, near gla- cial margin, 117, 118. Dies, England, 266. Dnieper, the, 185, 188. Don, the, 186, 188. Dora Baltea, 184. Dover, N. H.,.seetion of kame near, 77. Dover, Straits of, 238. Drave, glaciers in the, 134. Drainage systems in the Glacial period, 335, 389, 840, 343, 344 ; chap- ter on, 193-241. Drayson, cited, 817. Driftlesss area in the Mississippi Valley, 101, 102. Drumlins, description of, 73 et seq. ; view of, 73 ; occurrence of, in Mas- sachusetts,73 ; in New Hampshire, 74; in Connecticut, 74, in New York, 74, 94 ; in the British Isles, 74 137, 167. Dunbar, Scotland, 312. Dupont, cited, 279. Du Quoin, 111., 98, 119. D'UrviUe, 20. Diisseldorf, 275. Eagle, Wis., view of kettle-moraine near, 99. East Anglian Glacier, 158-164. Eccentricity of the earth's orbit, 308. Eden Valley, 180. Eggischorn, 211, 241. Eguisheim, skull found at, 279. Elephant, 265, 280, 282, 288, 292. Elevation, preglaoial, 112, 194,198; the cause or the Glacial period, 118, 320-331 ; about the Great Lakes, 224 ; in the latitude of New York, 261. Elyria, Ohio, 342. Engis skull, view of, 274. England. (See British Isles.) Enville, England, 160. Erosion, preglacial, 198 et seq. Erosion in river valleys, 198, 329, 332. Erzgebirge, 136, 181. Europe, existing glaciers in, 9 et seq., 43 et seq. ; ancient glaciers of, 129- 378 MAN AND THE GLACIAL PERIOD. 190 ; former elevation of, 238 ; ice- dams in, 360. Evans, cited, 263, 267, 354, 365. Falconer, cited, 263. Falls of St Anthony, 209. Faudel, cited, 279. Fiesch, Switzerland, 131, 211. Filey Brigg, Eng., 155. Finchley, Eng., 158, 159. Finger Lakes, 94 Finsteraarhorn, 9. Fiords, 194 et seq. : of Greenland, 212. Fissures in glacial ice, 3, 48, 49. Flamborough, 140, 156, 157, 176. Florida, 314. Flower, cited 263. Forbes 9, 38,' 43, 44, 48. Forel, M., cited, 116. Fort Snelling, Mississippi gorge at, 208, 340 et seg. Fort Wayne, Ind., 220, 224. Foshay, cited, 119. Fox, 270, 289, 290. Fraipont, cited, 275 et seq. France, existing glaciers of, 19 ; an- cient glaciers of, 136 ; glacial gravels of, 262 et seq. Frankley Hill, England, 150. Franklin, Pa., 230, 232. Franz-Josef Land, 14. Frederickshaab Glacier, 91, 212. Frere, cited, 266. Frickthal, 138. Frondeg, Wales, 149, 178. Gabb, cited, 318. Galloway, ancient glaciers of, 144, 145,154,157,167,168,173. Garda, Lake, moraine in front of, 135. Garonne, the, 136, 188. Gaudry, cited, 268. Geikie, Archibald, cited, 272, 312. Geikie, James, on kames, 76 ; on loess, 187, 188; cited, 291 et seq., 307, 853. Genesee Eiver, 220. Geological time, 361 et seq. Georgian Bay, 889. German Ocean, 129. Germantown, Ohio, 107, lOS. Germany, North, moraine in, 181, 183 ; glacial lakes in, 288 ; Qua- ternary animals in, 279. Gietroz Glacier, 211. Gilbert, oited^ 288 et seq., 350 et seq. ; on age of Isiagara gorge, 339. Glacial dispersion. (See Centres of Glacial Dispersion.) Glacial boundary in New England, 67 ; in New Jersey, 83 ; in Penn- sylvania, 84 et seq. ; in New York, 84; in Ohio, 95, 100, 106 ; in Ken- tucky, 96 ; in Indiana, 96 ; in Illi- nois, 96, 100 ; in Kansas, Nebraska, Missouri, Montana, South Dakota, 96 ; in Minnesota, 101 ; in British Isles, 137, 148, 150, 151, 155, 167 ; in Holland, 181 ; in Germany, 181, 188; inEussia, 181,189. Glacial erosion, 118, 119, 182. Glacial ice, depth of, in Pennsyl- vania, 90 et seq. ; in Connecticut, 91 ; in New York. 91 ; in Green- land, 91 • in the Alps, 91, 131, 133, 182 ; in Germany, 182 ; in Noi-way, 182 ; amount of, 330. Glacial lakes in Germany, 283. Glacial motion, limit of, 2 ; chapter on, 48-50 ; plastic theory of, 48. Glacial outlets of the Great Lakes, 220-222. Glacial periods, cause of, 113 ; chap- ter on, 802-381 ; date of, chapter on, 332-364. Glacial periods, supposed succession ofj 106 et seq., 811, 324-326, 382 ; criticisms of the theory, 116 et seq. Glacial strise. (See Eock-Sooring.) Glacial terraces, 229-238 ; in Penn- sylvania, 87 et seq., 215, 217, 229, 280 ; in New Y'ork, 88 ; at Beech Flats, Ohio, 217 ; at Granville, Ohio, 227 ; on the Minnesota Eiver, 228 ; around Great Salt Lake, 233 et seq. ; on Delaware Eiver, 243 et seg. ; in Europe, 238-241 ; in Ohio, 249 et seq. ; human relics in, 241- 267 ; on Delaware Eiver, 245 ; of the Mississippi Eiver, 254; in France, 263 et seq., 860 ; in Eng- land, 264 et seq. ; in Belgium, 264; in Spain, 264 ; in Portugal, 264 ; in Italy, 264 ; in Greece, 264. Glacial theory, crucial tests of, 62, 65. 257, 302 et seg. Glaciation, signs of past, chapter on, 61 et seq. Glacier Bay, 24 ; map of, 25. Glacier, defined, 2 ; formation of, 3 ; characterised by veins and fissures, 8; advance and retreat of, 116; velocity of, in the Alps, 43 et seq., in Greenland, 86, 46-48 ; in Alaska, 47, Glaciere, ancient, in North America, 66-128 ; in Central and Northern Europe, 68-60, 131-186 ; in the British Isles, 186-181 ; in Northern IJNJJKA. 3Y9 Europe, 181-190 ; in Australia, 126, 192 ; m Asia, 190, 191 : in Africa. 191, 192. Glaciers, existing, in the Alps, 9 et seq., is et seq. ; in Scandinavia, 12 ■ in Spitzbereen, Nova Zembla, and Franz-Joser Land, 12; in Ice- land, 14 ; in Asia, 14 et seq. ; in Ooeanioa, 16 ; in South America, lY; in Antarctic Continent, 18 et seq. ; in North America, 20 et seq. ; in Greenland, 32 et seq., 46, 48, 364. Glen Eoy, parallel roads of, 239. Glutton, 293. Goat, 268. Goffstown, N. H., 73. Grafton, W. Va., 214. Grand Havenj Mich., 346. Granville, Ohio, terrace at, 227, 343. Grape Creek, Col., view of moraines of, 123. Great Bend, Pa., depth of river- channel at, 206. Great Lakes, depth of, 115 ■ forma- tion of, 199 et seq. ; glacial outlets of, 220-222 ; elevation about, 224. Great Salt Lake, Utah, 233 et seq., 350, Greece, human relics in glacial ter- races of, 264. Greenland, existing glaciers of, 1, 32 et seq., 46, 48, 364 ; map of, 33 ; climate of, 302. Gross Glockner, 9, 184. Ground ioe, 357. Gulfof Mexico, 313, 318. Gulf Stream, 13, 311, 313, 317 et seq. Guyot, 9, 58, 133. Haas, 16. Hall, on the age of Niagara, 336. Hare, 289. Harrison, quoted, 167. Harte, Bret, cited, 296. Hartz Mountains, 136, 181. Hayes, 36. Haynes on Tertiary Man, 365-374. Heald Moor, England, 147. . Hebrides, the, 136. Heim, 9. Holland, 14, 46-48. Hennepin, cited, 340. Heme Bay, England, 265. Hersohel, cited, 310. Hertfordshire, England, 158. Hicks, Dr. H., cited, 272. Hicks, L. E., cited, 343. Himalayas, 1, 15, 292, 330 ; age of, 828. Hingham, Mass., section of kame near, 79. Hippopotamus, 263, 265, 271, 280, 284, 285, 290, 292. Hitchcock, C. H., discovery of boulders on Mount Washington, 60 ; on drumlins, 73 ; cited, 309, 313. Hitbhoook, E., on kames, 77. Holland, terminal moraine in, 181. Holdernesa, 157. Hooker, cited, 191. Horse, 188, 263, 268-270, 272, 278, 280, 288, 289. Horseheads, N. Y., 220. Horseshoe Fall, 337 et seq. Hottentot skull, 276. Hoxney, England, 266. Hudson Eiver, preglacial channel of, 194 et seq. Hugi, 9, 43. Hungary, Quaternary animals in, 279 Huxley, cited, 276, 278. Hyena, 271, 272, 282, 291, 292. Ibex, 289. Icebergs, 18, 20 ; formation of, 28. Ice, characteristics of, 2, 48 et seq., 302 et seq. ; transporting power of moving, 5. Ice-dams, 211-228 ; in the Alps, 211 ; in the Himalayas, 211 ; in Green- land, 212; in Alaska, 212; at Cin- ciimati, 213 et seq. ; across the Mo- hawk, 92, 220, 834, 335 ; in the Red Eiver of the North, 225 ; in Eu- rope, 360. Iceland, existing glaciers of, 1, 14. Ice-pillars, 6, 27. Ice-sheet, retreat of, 333 et seq. Idaho, 122 ; lava-beds of, 297. lUicilliwaet Glacier, 28. Illinois, 96-98, 100, 119, 121, 345 et seq. Indiana, 96, 98, 107, 119, 121. Indian Eidge, 80. Iowa, 98, 101. Ireland, ancient glaciers of, 143. Irish elk, 270, 278, 288. Irish Sea Glacier, 137, 145-153, 164, 271. Irthing, valley of the, 153. Is^re, glaciers of the, 132. Isle ofMan, 164^167. Isle of Wi^ht, 266. Italy, existing glaciei-s of, 9 ; ancient glaciers of, 135; human relics in glacial terraces of, 264 ; supposed Tertiary man in, 366. Ivrea, 134. 380 MAN AND THE GLACIAL PEKIOD. Jackson, cited, 357. Jackson's Lake. 123. Jakobshavn Glacier, velocity of, 46, 47 ; depth of, 91 ; ice-dams of, 212. James, cited, 204. James Eiver, Dak., 228; James Eiver, Va., 267. Jamieson, cited, 330. Jensen, 91. Judge's CavCj 72. Jura Mountams, ancient glaciers of, 58-60, 132. Kames, formation of, 7, 76, 77 ; of Muir Glacier, 29, 30 ; in Massachu- setts, 77 et seq.; in New Hamp- shire, 80 ; map of, in Maine, 81 ; in Pennsylvania, 87. Kanawha Kiver, 216. Kane, 36-38. Kansas, 96. Kelly's Island, view of grooves on, 103, 105. Kendall, chapter by, 137-181 ; cited, 273. Kent, England, 265. Kent's Hole, 267 et seq., 352 et seq. Kentucky, 63, 96, 97, 212; view of boulder in, 63. Kentucky Kiver, 214. Kettle-holes, formation of, 7, 68 ; of Muir Glacier, 29, 30 ; in New Eng- land, 66 et seq., 344, 346; in Penn- sylvania, 86 ; sedimentation of, 333, 344 et seq. Kettle-moraine in Wisconsin, 100. King, 21. 351 ; implement discov- ered by, 297. Knox County, Ohio, 232. Kurtz, Nampa image discovered by, 297. Lake Agassiz, 126, 223, 225; con- tinuance of, 347 et seq. Lake Bonneville, 233 et seq., 299, 350 et seq. Lake Constance, 60, 133. Lake Erie, origin of, 200 et seq. ; ridges around, 222 ; preglacial out- let of, 200, 333. Lake Geneva during the Glacial pe- riod, 131, 132. Lake Huron, preglacial outlet of, 202 : ridges around, 224. Lake Itasca, 254. Lake Lahontan, 283, 234. Lake Michigan, age of, 345 et seq. Lake Nipissing, 339. Lake Ontario, origin of, 201 et seq. Lake Traverse, 208, 226. Lake District, England, the, 144. Lake dwellings in Switzerland, 281. Lake ridges, 222 et se^. Lakes, sedimentation of, 333, 344 et seq. Lamplugh, glacial observations of, 140, 196. Lancashire, 163, 178, 180. Lancaster, Ohio, 232. Lang, cited, 116. Lark, England, valley of the, 266. Lateral moraines, 6. Laurentide Glacier, 113 et seq., 121, 321. Lava on the Pacific coast of North America, 294, 298, 300, 306, 321. Lawrence, Mass^ 80. Lawrenoeburg, Ind., 231, 232. Le Conte, cited, 286, 322 et seq., 330, 372. Leicestershire, England, 158. Lehigh Kiver, 243. Lemming, 289. Lenticular hills, 73. Leopard, 282. Lesley, cited, 215. Lesse, Belgium, valley of the, 279. Leverett, cited, 101, 218. Lewis, on transported boulders, 57, 61 ; work of, m Pennsylvania, 84, 119; in Great Britain,"l37; cited, 254 et seq., 273. Lickey Hills, 161. Licking Kiver, 214. Lidge, Belgium, 274. Lincolnshire, England, 168. Lindenkohl on old ohannel of the Hudson, 195 et seq. Lion, 282, 293. Little Beaver Creek, 231, 232. Little Falls, Minn., 226, 232, 252, 264. Little Falls, N. Y., buried channel near, 202. Livingston, Mont., 122. Llangollen, vale of, 151. Loess in the Mississippi Valley, 98, 119, 120 ; in Europe, 186 et seq. Lohest, cited, 276 et seq. Lombardy, 134. London, 168, 159, 178; glacial ter- race in, 264. Long Island, 66, 67. Louisville, Ky., buried channel near; 205. Loveland, Ohio, 232, 250. Lubbock, cited, 267. Lucerne, 133. Lyell, on Kichmond train of boul- ders, 70 ; cited, 239, 263, 267, 274, 276, 285, 355, 361 ; on the age of Niagara, 336. Lyons, 132. Maaok, cited, 318. Macclesfield, England, 273. MaoEnery, cited, 267. Machaii'odus, 270, 282. Mackintosh, quoted, 149, 150, 173. Macon, France, 369. MoTarnahan, mortar discovered hy 297. Madison houlder, 71. Madisouville, Ohio, 232, 250, 25i. Magdalcna Bay, 13. Mahoning River, 220. Maine, 80 ; re-elevation of^ 331. Malaspina Glacier, map of, 31. Mammoth, 188, 190, 263, 265, 269- 272, 278, 280, 283-285, 287, 292, 293. Man, relics of, in the Glacial period, chapter on, 242-301 ; in glacial terraces of the United States, 242- 262 ; of Europe, 262-267 ; in cave deposits of British Isles, 148, 267- 274; of the Continent, 274^281; under lava-beds of the Pacific coast of North America, 294^301 ; extinct animals associated with, 281-293. Manitoba, 97. Mankato, Minn., 229. Marcilly, skull at, 279. Marietta, Ohio, 231. Marmot, 289, 293. Marsh Creek Valley, Utah, 233. Martigny, ancient glaciers near, 59, 60, 131, 211. Massachusetts, 67 et seq., 73, 77 et seq., 81, 344, 345. Mastodon, 262, 278, 285, 286. Mattmark See, 211. Maumee Kiver, 220. MoGee, cited, 245, 254 et seq. Medial moraines, formation of, 6 ; of Muir Glacier, 27 ; in Ohio, 100. Medlioott, cited, 312. Medora, Ind., 232, 251, 254. Menai Straits, 145. Mentone, skeleton of, 281. Mer de Glace, 11, 44. Merjelen See, 211, 241. Mersey, the, 140. Meteorites, 305. Metz, cited, 250. Meuse, valley of, 274 et seq. Miami, the (5-reat, 204, 220. Miami, the Little, 231, 250. Millersburg, Ohio, 232. Mills, cited, 251. 26 ttA. 381 Minneapolis, 232 ; buried outlet near, 208 ; recession of falls at, 210, 340 et seq., 364. Minnehaha, Falls of, 342. Minnesota, 101, 107, 252 et seq. ; lakes of, 344. Minnesota Elver, a glacial outlet, 208, 225, 228, 342. Miocene epoch, animals of the, 285. Mississippi Elver, gorge of, at Fort Snelling, 208, 364 ; terraces on, 229 ; erosion by, 329; glacial drainage of, 335, 340. Missouri Coteau, 101, 126, 228. Missouri, 96, 98, 119. Moel Tryfaen, 145, 167 et seq., 178, 273. Mohawk Kiver, glacial drainage of, 92, 202, 335; ice-dam across, 220, 334, 335. Mohegan Kock, 71 ; view of, 72. Monongahela Kiver, 214 et seq. Montaigle, valley of the, 279. Montana, 96. Montreal, re-elevation of, 331. Moose, 262. Moraines, formation of, 6; in Wis- consin, 98-100; in Italy, 134, 135; between Speeton and Flambor- ough, 156 : m Germany, 183. Morecambe Bay, 146, 180. Morgantown, W. Va., 215. Morlot, cited, 354. Mortillet, cited, 366, 369, 372. Morvan, the, 136. Moulins, formation of, 7. Mount Shasta, 21. Mount ■Washington, 61. Mueller Glacier, 17. Muir Glacier, 24 et seq., 47, 68, 212 ; view of front of, 26. Muir, John, 24. Muskingum Elver, 220, 231. Musk ox, 262, 280. Musk sheep, 289, 290, 293. Nampa image, 297 et seq. Nansen, 39, 41. Naulette, jaw found at, 278, 279. Neale, implements discovered by. 296, 373. Neanderthal skull, 275 et seq. Nebraska^ 96. Nelson Eiver, 349. Neufchatel, 133. Nevada, 124; lakes of, 233. N^v^-fleld defined, 3. Newark, Ohio, 232. Newberry on the preglacial drainage of the Hudson, 195 et seq. ; on the 382 MAN AND THE GLACIAL PERIOD. formation of the Great Lakes, 202 et seq. ; cited, 320. Newburg, N. Y., 286. New Comerstown, implement from, 232, 250, 251 et seq., 254. New England, 57, 60, 61, 91; an- cient glaciers in, 66-83. New Hampshire, 69, 71, 74, 80. New Harmony, lud., 232. New Jersey, 83. New Lisbon, Ohio, 232. New York, 74, 84, 88, 91, 92 et seq. New York Bay, 184, 197, 249. New Zealand, 1, 126, 192, 330. Niagara gorge, age of, 333 et seq.; section of strata along the, 336. Nile Eiver, 285. NordenskiSld, 32, 34. Norfolk, EAgland, 161. North America, existing glaciers in, 20 et seq North Sea, 238. Norway, climate of, 314. Nottingham, England, 164. Nova Zembla, 14. Nunataks, 27, 32. Oberlin, Ohio, 64, 344. Ooeanica, existing glaciers of, 16, 17. Ohio Kiver, glacial terrace, 217, 229. Ohio, 64, 72, 95, 98, 100, 103, 106, 107- 117, 119, 217, 249 et seq., 343, 344. Oil Creek, 205, 232. Olmo, skull at, 279. (.)regon, 21, 124. Orme's Head, Little, 147. Orton, cited, 72, 107. Oscillations of land-level in Amer- ica, 124 et seq. Oswestry. England, 173. Ottawa Kiver, 339. Otter, 290. Ouse, valley of the, 265. Ox, 269, 270. Pacific coast of America, 349. Pacific Ocean, 318, 320. Panama, Isthmus of, 113, 313, 314, 318. Parsimony, law of, 117. Pasterzeu Glacier, 134. Patagonia, 1. Patton, 25. Payer, 14, 39. Peat-beds, 68, 125 ; in Ohio, 107 ; in Minnesota, 108 ; in valley of the Somme, 355 et seq. Pembina Eiver, 228. Pengelly, cited, 267, 270. Pennine Chain, glaciation of, 137, 144, 146, 147, 154, 177. Pennsylvania, 57, 61, 84 et seq., 119, 217. Perrv County, Ohio, 282. Perthes, Boucher de, 262 et seq. Philadelphia Academy of Sciences, 296. Philadelphia, red gravel of, 254 et seq. Phillips, cited, 267. Picardy,' glacial gravels of, 262. Pittsburg, Pa., submergence of, 214. 217 230 Plum' Creek, Ohio, 344. Po, valley of the, 135; erosion by, 328 Pocatello, Idaho, 236, 299. Pocono Mountain, 61. Poland, 181. Polynesian skull, 276. Pomp's Pond, section of kettle-hole near, 345. Portageville, N. Y., 220. Port Nouf Kiver, Idaho, 236. Portsmouth, Ohio, 231. Portugal, human relics in glacial terraces of, 264; supposed Ter- tiary man in, 867, 371 et seq. Post-glacial erosion, 332 et seq. ; in Ohio, 343, 344; in Illinois, 345 et seq. Potomac Eiver, 256 et seq. Pot-holes in Lucerne, 133. Pouchet, cited, 263. Precession of equinoxes, 308. Preglacial climate in England, 141, 142. Preglacial levels in England, 139- 142. Prestwioh, cited, 186, 189, 263 et seq., 284 ; on date of Glacial period, 354, 357, 363, 364. Provo shore-line, 237. Putnam, cited, 250. PuT-Courny, France, supposed Ter- tiary man at, 367, 370, 371. Pyramid Lake, 350. Pyrenees, glaciers of the, 11, 136 ; Quaternary animals of, 280, 282; age of, 328. Quaternary animals of California, 281, 287; in Germany, 279; in Hungary, 279. Quatrefages, cited, 276. Queenston, Canada, 333 et seq. Rabhit, 289. Eaoooon Creek, 343 ; view of glacial terrace near, 227. Eames, cited, 370, 371. INDEX. S83 Eamsay, cited, 811. Eappahannook Eiver, 257. Kawhide Gulch, Cal., 296. Eeoession, rate of, of Falls of Ni- agara, 338 et aeq. ; of Falls of St. Anthony, 340 et seq., 364 ; of Black Eiver, 342, 343. Eed deer, 263. Eed Eiver of the North, 209, 228, 340 ; ice-dam in, 225. Eegillout, 263. Eeid, Clement, quoted, 162. Eeid, H. F., 26, 47. Eeindeer, 188, 262, 263, 269, 270, 278, 280, 287, 290, 293. Ehine, ancient glaciers of the, 1 29, 1 33. Ehinooeros, 188, 263, 265, 271, 277, 278, 280, 284, 286, 287, 292 ; woolly, 269, 270, 272, 280, 287. Rhode Island, 67. Ehone, ancient glaciers of, 58-60, 131, 132, 185, 188 ; map of, 58. Eichmond, Mass., train of boulders in, 70, 71. Eink, Dr., 35. Eoanokc Eiver, 257. Eooky Mountains, 320, 322; age of the, 328. Eoek-scorings, cause of, 51 et seq. ; in New England, 69; on islands of Lake Erie, 103, 104; in Pennsyl- vania, 119 ; in Ohio, 103, 119 ; in Indiana, 119; in Illinois, 119; in Missouri, 119. Eoman remains, 356. Kome, N. Y., 335. Eosa, Mount, 9, 134, 211. Boss, Sir J. C., 18, 19, 311. Edyston, England, 155. Eunaway Pond, 207. Eussell, I. C, exploration of Mount St. Elias by, 30, 212 ; cited, 233, 350 et seq. Eussia, glacial boundary in, 181, 189 ; glacial drainage of, 238. Saeuenay, fiord of the, 197. Salamanca, N. Y., buried channels near, 206. Salisbury, cited, 183, 184. Salt Lake City, 123. Sandusky, Ohio, section of the lake ridges near, 223. Sandusky Eiver, 220. Sanford, cited, 267. Saskatchewan Eiver, 228. Sa.xony, 181. Scandmavia, existing glaciers of, 2, 12 ; ancient glaciers of, 129, 136, 157, 181-190- re-elevation of, 331. Scioto Eiver, 231. Scotland. ^See British Isles.) Seattle, section of till in, 55. Second Glacial period, 106 et seq. Section, ideal, across river bed m drift region, 229. Sedimentation of lakes, 333. Seine, terraces of the, 186, 188, 264. Seraos, 4, 5. Settle, England, 270. Severn, the, 149-151, 285. Shaler, 67, 242. Shap granite, 154, 157, 180. Ship Eock, 71. Shone, cited, 180. Shoshone Falls, 299. Shrewsbury, England, 150. Shropshire, England, 149, 173. Siberia, 190 ; Quaternary animals in, 280, 282, 283, 290 ; olunate of, 302, 316. Sierra Nevada Mountains, 21, 294, 301, 320, 322, 349, 352. Skertohly, quoted, 159. Skipton, 144, 146. Skull, comparative study of, 276. Slickenside, 53. Smock on depth of glacial ice, 90. Snake Eiver Valley, 236 et seq., 298. Snowdon, 145, 171. Snowy vole, 289. Soleure, 183. Solferino, 135. Solway Glacier, 153, 155, 180. Somme, teiTaces of the, 186, 262 et seq., 285, 286, 355, 359 et aeq. Sonora, Cal., 294 et seq. South America, existing glaciers of. 17 ; ancient glaciers in, 126. Southampton, England, 266. South Dakota, 96, 98. Spain, ancient glaciers of, 136 ; human relics in glacial terraces of, 264 ; Quaternary animals of, 280. Speeton, 140, 155, 156. Spencer, cited, 224. Spencer, N. Y., 220. Spitzbergen, 12. Spy, man of, 275, 277. St. Aoheul, 263. Stag, 289. Stainraoor, England, 154, 157, 180. Stalagmite, rate of accumulation of, 352 et seq. Stanislaus Kiver, Cal., 294. St. Anthony, Falls of, 340 et seq., 364. Steamburg, N. Y., buried channel at, 206. St. Elias, 30 et seq., 212. 384 MAN AND THE GLACIAL PERIOD. St. Lawrence Kiver, glacial drainage of; 335, 339. St. Louis, Mo., 119, 364. St. Paul, Minn., 228. Stone on kames in Maine, 80. Straits of Dover, 360. Straits of Gibraltar, 292. Strise, direction of, in New Hamp- shire, 69 ; in Lake Erie, 104 ; pres- ence of, in Pennsylvania, 85, 119 ; in Ohio, Indiana, Illinois, and Mis- souri, 119 ; in Stuttgart, 2T9. Subglaoial streams, 23, 29, 120. Submerged channels on the coasts of America, 194-198. Submergence theory, 60-63, VO. Subsidence of the Isthmus of Pana- ma, 113, 318 ; In Mississippi Val- ley, 93, 113, 120, 121 ; on east coast of North America, 255 et seq. ; about the Great Lakes, 224, 339 ; in Great Britain, 167-181. Susquehanna River, glacial drainage 0^ 93, 232, 257. Svartisen Glacier, 13. Svenonius, Dr., 12. Sweden, 81. Switzerland, existing glaciers of, 9- 11 ; ancient glaciers of, 131-136 •, lake-dwellings in, 281. Table Mountain, Gal., 294 et seq., 300. Table of changes during the Glacial epochs, 324, 325. TaguB, valley of the, 367, 371 et seq. Tait, cited, 862. Tardy, cited, 370. Tasman Glacier, 16. Teesdale, England, 155, 15V. Terminal moraines, formation of, 6 ; in Pennsylvania, 61, 62, 85 et seq. ; on the southern coast of New Eng- land, 66 et seq. ; in Ohio, 106 : m Puget Sound, 122; in Tyghee Pass, 122; in Italy, 135. Terminal moraines of the second Glacial epoch, 93, 100, 101, 106. Terraces. (See Glacial Teekaqes.) Tertiary animals, 286. Tertiary man, 365-374. Tertiary period, climate of, 113, 117, 182, 305, 307. Teton Mountains, 123. Texas, Pleistocene animals of, 288. Thames, England, 138, 264, 285. Thenay, Prance, supposed Tertiai-y man in, 367, 371 ; view of fiint- flakes collected at, 368. Thompson, 50. Thomson, cited, 362. Till, description of, 53 ; composition , of, in Massachusetts, 81 et seq. ; section of, in Ohio, 108; depth of, in Germany, Scandinavia, and Bussia, 182. Tini^re Kiver, 354. Titusville, Pa., 232. Todd, on forest beds and old soils, 110 «<«c?.; cited, 228. Torquayj England, 267. Trade-winds of the Atlantic, 314, 318. Tremeirchon, Wales, 271. Trenton, N. J., 87, 232, 242 et seq., 254, 257 ; view of implement found at, 247. Trenton gravel, section of the, 246. Trent, vSley of the, 163, 164. Trimmer, quoted, 148. Trimingham, England, 162. Trogen, Switzerland, 60. Trons, Switzerland, 60. Tuolumne County, Gal., 294, 299. Tui-in, 135. Tuscarawas Valley, 220, 221, 232, 251 ; buried channel in, 205. Tylor, cited, 359 et seq. Tyndall, 44^46, 49. Tynemouth, England, 155, 157. Tyrol 134, 135, 211. TyiTell, cited, 109. Ulm, 134. Upham, on drumlins, 73 ; on two ice- movements, 97 ; cited, 222, 253 et seq., 301, 318, 320 et seq., 330, 348 : on the Columbia gravel, 261 ; on date of the Glacial period, 344. Dral Mountains, 15, 280. Utah, 123 ; lakes of, 233. Utica, N. Y., 220. Utrecht, moraine near, 181. Valais, the, 133. Vegetable remains in glacial de- posits, 117, 125 ; in Ohio, 107, 117 ; in Indiana, 107 ; in Minnesota, 107, 109; in Iowa, 108; in British America, 109. Veins in glacial ice, 3. Vermont, Eunaway Pond in, 207. Vernagt Glacier, 211. Vessel Eock, view of, 56. Vozere, valley of, 281. Victoria Cave, England, 270, 280. Virginia City, 349. Vivian, cited, 267. Volga, the, 185. Vosges Mountains, 136. INDEX. 385 "Watash Eiver, 220, 231, 232. Wahaatoh Mountains, 287. Wales, ancient glaciers of, 143, 150 et seq. ; cffivems of, 271. "Wallace, cited, 331, 343, 362. Walrus, 262, 285. Warren, Pa., buried channel near, 206. Wan-en Eiver, 226. Washington, 1, 21, 122. Washington, D. C., gravel deposit of, 254. Water, transporting power of run- ning, 5, 51-53. Waveney, England, valley of the, 266. Wealden formation, 361. Weasel,290. Wells, England, 270. Western Reserve Historical Society, 104. Weston, W. Va., 216. West Virginia, 214 et seq. ; glacial terrace m, 216. Wey, valley of the, 265. Whitby, England, 155. White, cited, 215 et seq. White Eiver, Ind., 232, 251. White Sea, 181. Whitney, 14, 21, 295, 349, 373. Whittlesey, 100. Wild-boar, 290. Wild-cat, 290. Winohell, Alexander, cited, 321, 330. Winchell, N. H., cited, 107, 210,252; on the Falls of St. Anthony, 341 et seq. Wisconsin, 98, 99, 100, 101. Woeikoif, cited, 316. Wolf, 270, 290. Wolverine, 289. Wood, cited, 179. Woodward, quoted, 160; on age of Niagara, 337 et seq. Wookey Hole, England, 270. Wrangell, cited, 357. Wright, 373. ■Yankton, 120. Yellowstone' Park, 122. Yorkshire, 140,154, 155, 157, 176,270, 283, 286. Yosemite Park, 21, 350. Young, Eev. Mr., 24. Young, Professor, cited, 362. Younglove, 104. Zermatt Glacier, view of, 2. Zuyder Zee, 181. THE END. ' " " ^- ^ 'wnif ^, j»a*-* HP.-