More conclusive than these are the repeated discoveries of implements, chipped from hard stones, in deposits of loess and gravels in Ohio and Indiana, which deposits, without doubt, represent a closing episode of the last Glacial Epoch. There may be some question about the geologic age of the former finds, but about these there is none. They prove beyond cavil that during the closing scenes of the Quaternary in North America, man, tool-making, fire-using man, was present and active.16 This decision is not only confirmed, but greatly extended, by the researches of Dr. C. C. Abbott and others in the gravels about Trenton, on the Delaware. These were laid down contemporaneously with the terminal moraine in Ohio and Indiana, from which the palæoliths were exhumed. Abbott’s discoveries include several hundred stone implements of the true palæolithic or “Chelléen” type, and some fragments of human skeletons.17 They reveal to us not only the presence of man, but a well defined stage of culture strictly comparable to that of the “river drift” men of the Thames and the Somme in western Europe, which has been so ably described by De Mortillet.18
Such discoveries have not been confined to the northern portion of the continent. Barcena reported the relics of man in a quaternary rock in the valley of Mexico.19 The geologists of the Argentine Republic describe others which must be referred to a very remote age. The writers who have given the most information about them are Ameghino and Burmeister. They found bone and stone implements of rude form and the remains of hearths associated with bones of the extinct horse, the glyptodon, and other animals now unknown. The stratigraphic relations of the finds connected them with the deposits of the receding Austral glacier.20
Such facts as these place it beyond doubt that man lived in both North and South America at the close of the Glacial Age. It is not certain that this close was synchronous in both the northern and southern hemispheres, nor that the American glacier was contemporary with the Ice Age of Europe. The able geologist, Mr. Croll, is of opinion that if there was a difference in time, the Ice Age of America was posterior to that of Europe. In any case, the extreme antiquity of man in America is placed beyond cavil. He was here long before either northern Asia or the Polynesian islands were inhabited, as it is well known they were first populated in Neolithic times.
The question naturally arises, did he not originate upon this continent? The answer to this is given by Charles Darwin in his magistral statement—“Our progenitors diverged from the catarhine stock of the anthropoids; and the fact that they belonged to this stock clearly shows that they inhabited the Old World.”21 In fact, all the American monkeys, whether living or fossil, are platyrhine, have thirty-four teeth, and have tails, characteristics which show that none of the higher anthropoids lived in the New World.
We are obliged, therefore, to look for the original home of the American glacial man elsewhere than in America. Some interesting geological facts throw an unexpected light upon our investigations. I have already remarked that in the various recent oscillations of the earth’s crust, there occurred about the middle and later Glacial Epoch an uplift of the northern part of the continent and also of the northern Atlantic basin. In the opinion of Professor James Geikie this amounted to a vertical elevation of three thousand feet above the present level, and resulted in establishing a continuous land connection between the higher latitudes of the two continents, which remained until the Post-glacial period.22 Dr. Habernicht also recognizes this condition of affairs and places it during the “old stone” age in Europe,23 which corresponds to the position assigned it by McGee.
Very recently, Professor Spencer has summed up the evidence in favor of the elevation of the northern portions of America and the north Atlantic, about the early Pliocene times, and considers that it proves beyond a doubt that it must have reached from 2000 to 3000 feet above the present level.24
Further testimony to the existence of this land bridge is offered by the glacial striæ on the rocks of Shetland, the Faroe Islands, Iceland and south Greenland. These are in such directions and of such a character that Mr. James Croll, a high authority, maintains that they must have been produced by land ice, and that the theory of a land connection between these localities “can alone explain all the facts.”25 A comparison of the flora and fauna in the higher latitudes of the two continents reveals marked identities which require some such theory to explain them. Thus, certain species of land snails occur both in Labrador and Europe, and the flora of Greenland, although American in the north, is distinctly European in the south.26
Again, in certain very late Pliocene formations in England, known as the Norwich crag and the red crag of Suffolk, “no less than eighteen species of American mollusca occur, only seven of which still live on the Scandinavian coast, the remainder being confined to North America.” In consequence of such facts the most careful English geologists of to-day hold that the land communication, which certainly existed between Europe and North America in Eocene times by way of Iceland and Greenland, which was then a part of the American continent, continued to exist through the Miocene and Pliocene Epochs. This land bridge formed a barrier of separation between the Arctic and Atlantic oceans, so that the temperature of the higher latitudes was much milder than at present.27
The evidence, therefore, is cumulative that at the close of the last Glacial Epoch, and for an indeterminate time previous, the comparatively shallow bed of the North Atlantic was above water; and this was about the time that we find men in the same stage of culture dwelling on both its shores.
The attempt has often been made by geologists to calculate the remoteness in time of the close of the Ice Age, and of these vestiges of human occupation. The chronometers appealed to are the erosion of river valleys, especially of the gorge of Niagara, the filling of lake beds, the accumulation of modern detritus, etc. Professor Frederick Wright, who has studied the problem of the Niagara gorge with especial care, considers that a minimum period of twelve thousand years must have elapsed since its erosion began.28 But as Professor Gilbert justly remarks, whatever the age of the great cataract may be, the antiquity of man in America is far greater, and reaches into a past for which we have found no time-measure.29
The same may be said for Europe. De Quatrefages and many other students of the subject consider that the evidence is sufficient to establish the presence of man near the Atlantic coast in the Pliocene Epoch; and excellent English geologists have claimed that the caves in the valley of the River Clwyd, in north Wales, whose floors contain flint implements, had their entrance blocked by true glacial deposits, so that man was there present before the Great Ice Age began.
From this brief presentation of the geologic evidence, the conclusion seems forced upon us that the ancestors of the American race could have come from no other quarter than western Europe, or that portion of Eurafrica which in my lectures on general ethnography I have described as the most probable location of the birth-place of the species.30
Scheme of the Age of Man in America.
Many difficulties present themselves in bringing these periods into correspondence with the seasons of the Quaternary in Europe; but after a careful study of both continents, Mr. W. J. McGee suggests the following