But according to Professor Josiah Whitney there is reason for supposing that man existed in California at a still more remote period. The Calaveras skull. He holds that the famous skull discovered in 1866, in the gold-bearing gravels of Calaveras county, belongs to the Pliocene age.[10] If this be so, it seems to suggest an antiquity not less than twice as great as that just mentioned. The question as to the antiquity of the Calaveras skull is still hotly disputed among the foremost palæontologists, but as one reads the arguments one cannot help feeling that theoretical difficulties have put the objectors into a somewhat inhospitable attitude toward the evidence so ably presented by Professor Whitney. It has been too hastily assumed that, from the point of view of evolution, the existence of Pliocene man is improbable. Upon general considerations, however, we have strong reason for believing that human beings must have inhabited some portions of the earth throughout the whole duration of the Pliocene period, and it need not surprise us if their remains are presently discovered in more places than one.[11]
Whatever may be the final outcome of the Calaveras controversy, there can be no doubt as to the existence of man in North America far back in early Pleistocene times. The men of the River-drift, who long dwelt in western Europe during the milder intervals of the Glacial period, but seem to have become extinct toward the end of it, are well known to palæontologists through their bones and their rude tools. Contemporaneously with these Europeans of the River-drift there certainly lived some kind of men, of a similar low grade of culture, in the Mississippi valley and on both the Atlantic and Pacific slopes of North America. Pleistocene men and mammals. Along with these ancient Americans lived some terrestrial mammals that still survive, such as the elk, reindeer, prairie wolf, bison, musk-ox, and beaver; and many that have long been extinct, such as the mylodon, megatherium, megalonyx, mastodon, Siberian elephant, mammoth, at least six or seven species of ancestral horse, a huge bear similar to the cave bear of ancient Europe, a lion similar to the European cave lion, and a tiger as large as the modern tiger of Bengal.
Now while the general relative positions of those stupendous abysses that hold the oceans do not appear to have undergone any considerable change since an extremely remote geological period, their shallow marginal portions have been repeatedly raised so as to add extensive territories to the edges of continents, and in some cases to convert archipelagoes into continents, and to join continents previously separated. Such elevation is followed in turn by an era of subsidence, and almost everywhere either the one process or the other is slowly going on. If you look at a model in relief of the continents and ocean-floors, such as may be seen at the Museum of Comparative Zoölogy in Cambridge, showing the results of a vast number of soundings in all parts of the world, you cannot fail to be struck with the shallowness of Bering Sea; Elevation and subsidence. it looks like a part of the continent rather than of the ocean, and indeed it is just that,—an area of submerged continent. So in the northern Atlantic there is a lofty ridge running from France to Greenland. The British islands, the Orkney, Shetland, and Færoe groups, and Iceland are the parts of this ridge high enough to remain out of water. The remainder of it is shallow sea. Again and again it has been raised, together with the floor of the German ocean, so as to become dry land. Both before and since the time when those stone tools were dropped into the red gravel from which Mr. Cresson took them the other day, the northwestern part of Europe has been solid continent for more than a hundred miles to the west of the French and Irish coasts, the Thames and Humber have been tributaries to the Rhine, which emptied into the Arctic ocean, and across the Atlantic ridge one might have walked to the New World dry-shod.[12] In similar wise the northwestern corner of America has repeatedly been joined to Siberia through the elevation of Bering Sea.
There have therefore been abundant opportunities for men to get into America from the Old World without crossing salt water. Probably this was the case with the ancient inhabitants of the Delaware and Little Miami valleys; it is not at all likely that men who used their kind of tools knew much about going on the sea in boats.
Whether the Indians are descended from this ancient population or not, is a question with which we have as yet no satisfactory method of dealing. It is not unlikely that these glacial men may have perished from off the face of the earth, having been crushed and supplanted by stronger races. Waves of migration. There may have been several successive waves of migration, of which the Indians were the latest.[13] There is time enough for a great many things to happen in a thousand centuries. It will doubtless be long before all the evidence can be brought in and ransacked, but of one thing we may feel pretty sure; the past is more full of changes than we are apt to realize. Our first theories are usually too simple, and have to be enlarged and twisted into all manner of shapes in order to cover the actual complication of facts.[14]
In this connection the history of the Eskimos introduces us to some interesting problems. Mention has been made of the River-drift men who lived in Europe during the milder intervals of the Glacial period. At such times they made their way into Germany and Britain, along with leopards, hyænas, and African elephants. But as the cold intervals came on and the edge of the polar ice-sheet crept southward and mountain glaciers filled up the valleys, these men and beasts retreated into Africa; The Cave men of Europe in the Glacial Period. and their place was taken by a sub-arctic race of men known as the Cave men, along with the reindeer and arctic fox and musk-sheep. More than once with the secular alternations of temperature did the River-drift men thus advance and retreat and advance again, and as they advanced the Cave men retreated, both races yielding to an enemy stronger than either,—to wit, the hostile climate. At length all traces of the River-drift men vanish, but what of the Cave men? They have left no representatives among the present populations of Europe, but the musk-sheep, which always went and came with the Cave men, is to-day found only in sub-arctic America among the Eskimos, and the fossilized bones of the musk-sheep lie in a regular trail across the eastern hemisphere, from the Pyrenees through Germany and Russia and all the vast length of Siberia. The stone arrow-heads, the sewing-needles, the necklaces and amulets of cut teeth, and the daggers made from antler, used by the Eskimos, resemble so minutely the implements of the Cave men, that if recent Eskimo remains were to be put into the Pleistocene caves of France and England they would be indistinguishable in appearance from the remains of the Cave men which are now found there.[15] There is another striking point of resemblance. The Eskimos have a talent for artistic sketching of men and beasts, and scenes in which men and beasts figure, which is absolutely unrivalled among rude peoples. One need but look at the sketches by common Eskimo fishermen which illustrate Dr. Henry Rink's fascinating book on Danish Greenland, to realize that this rude Eskimo art has a character as pronounced and unmistakable in its way as the much higher art of the Japanese. The Eskimos are probably a remnant of the Cave men. Now among the European remains of the Cave men are many sketches of mammoths, cave bears, and other animals now extinct, and hunting scenes so artfully and vividly portrayed as to bring distinctly before us many details of daily life in an antiquity so vast that in comparison with it the interval between the pyramids of Egypt and the Eiffel tower shrinks into a point. Such a talent is unique among savage peoples. It exists only among the living Eskimos and the ancient Cave men; and when considered in connection with so many other points of agreement, and with the indisputable fact that the Cave men were a sub-arctic race, it affords a strong presumption in favour of the opinion of that great palæontologist, Professor Boyd Dawkins, that the Eskimos of North America are to-day the sole survivors of the race that made their homes in the Pleistocene caves of western Europe.[16]
If we have always been accustomed to think of races of men only as they are placed on modern maps, it at first seems strange to think of England and France as ever having been inhabited by Eskimos. Facts equally strange may be cited in abundance from zoölogy and botany. The camel is found to-day only in Arabia and Bactria; yet in all probability the camel originated in America,[17] and is an intruder into what we are accustomed to call his native deserts, just as the people of the United States are European intruders upon the soil of America. So the giant trees of Mariposa grove are now found only in California, but there was once a time when they were as common in Europe[18] as maple-trees to-day in a New England village.