Probably the favorite theory at the present day is that the first inhabitants of the New World came from northeastern Asia, either by the Aleutian islands or across Behring Strait. Concerning the Aleutian islands we know by the evidence of language and archæology that they were first peopled from America, and not from Asia. Moreover, they are separated one from the other in places by hundreds of miles of a peculiarly stormy and dangerous sea.5
It is otherwise with Behring Straits. From East Cape in Siberia one can see the American shore, and when first explored the tribes on each side were in frequent communication. No doubt this had been going on for a long time, and thus they had influenced each other in blood and culture. But so long as we have any knowledge of the movings at this point, they have been from America into Asia, the Eskimos pushing their settlements along the Asian coast. It will be replied that we should look to a period anterior to the Eskimos. Any migration at that remote epoch is refuted by other considerations. We know that Siberia was not peopled till late in the Neolithic times, and what is more, that the vicinity of the strait and the whole coast of Alaska were, till a very modern geologic period, covered by enormous glaciers which would have prevented any communication between the two continents.6 These considerations reduce any possible migrations at this point to such as may have taken place long after America, both North and South, possessed a widespread population.
The question which should be posed as preliminary to all such speculations is, When did man first appear on this isolated continent?
To answer this we must study its later geological history, the events which have occurred since the close of the Tertiary, that is, during the Quaternary age.
In North and also in South America that age was characterized by one notable event, which impressed its presence by lasting memorials on the surface of the continent. This was the formation of a series of enormous glaciers, covering the soil of nearly half the temperate zones with a mass of ice thousands of feet in thickness. The period of its presence is called the Great Ice Age or the Glacial Epoch. Beyond the immediate limits of the ice it may not have been a season of extreme cold, for glaciers form more rapidly when the temperature is not much below the freezing point. Nor was it continuous. The ice sheet receded once, if not twice, causing an “interglacial” epoch, when the climate was comparatively mild. After this interim it seems to have advanced again with renewed might, and to have extended its crystalline walls down to about the fortieth parallel of latitude, touching the Atlantic near Boston and New York harbors, and stretching nearly across the continent in an irregular line, generally a little north of the Ohio and a little south of the Missouri rivers. Enormous ice masses covered the Pacific Slope as far south as the mouth of the Columbia river, and extended over 1200 miles along the coast, submerging the whole of Queen Charlotte and Vancouver islands and the neighboring coast of British Columbia, which at that time were depressed about two hundred feet below the present level. The ice also covered for four hundred miles or more the plateau or Great Basin between the Rocky Mountains and the Coast Range, rising in some places in a solid mass five or six thousand feet above the soil.7
The melting of the second glacial inroad began at the east, and on the Pacific coast has not yet ceased. Its margin across the continent is still distinctly defined by a long line of débris piled up in “moraines,” and by a fringe of gravel and sand called the “overwash,” carried from these by the mighty floods which accompanied the great thaw. This period of melting is the “Post-glacial Era.” It was accompanied by extensive changes in the land-levels and in temperature.
In the glacial and early post-glacial periods, the northern regions of the continent and the bottom of the Northern Atlantic were considerably above their present levels; but in the late post-glacial or “Champlain” period the land had sunk so much that at Lake Champlain it was five hundred feet lower than now, and at New York Harbor ten feet lower. The St. Lawrence river was then an arm of the sea, Lake Champlain was a deep bay, and the mouth of the Delaware river was where the city of Trenton now stands, the river itself being a wide inlet.8
The climate, which in the early post-glacial period had been so cold that the reindeer enjoyed an agreeable home as far south as Kentucky, changed to such mildness that two species of elephants, the giant sloth and the peccary, found congenial pasturage in the Upper Ohio and Delaware Valleys.9
The interest which this piece of geologic history has for us in this connection is the presence of man in America during all the time that these tremendous events were taking place. We know he was there, from the evidence he has left behind him in the various strata and deposits attributable to the different agencies I have described. How far back his most ancient relics carry us, is not quite clear. By some, the stone implements from Table Mountain, California, and a skull found in the auriferous gravel in Calaveras county, California, are claimed to antedate any relics east of the mountains. These stone utensils are, however, too perfect, they speak for a too specialized condition of the arts, to be attributable to a primitive condition of man; and as for the Calaveras skull, the record of its discovery is too unsatisfactory. Furthermore, in a volcanic country such as the Pacific coast, phenomena of elevation and subsidence occur with rapidity, and do not offer the same evidence of antiquity as in more stable lands.
This is an important point, and applies to a series of archæological discoveries which have been announced from time to time from the Pacific coast. Thus, in Nicaragua, human foot-prints have been found in compact tufa at a depth of twenty-one feet beneath the surface soil, and overlaid by repeated later volcanic deposits. But a careful examination of all their surroundings, especially of the organic remains at a yet greater depth, leads inevitably to the conclusion that these foot-prints cannot be ascribed to any very remote antiquity.10 The singular changes in the Pacific seaboard are again illustrated along the coast of Ecuador and Peru. For some sixty miles north and south near the mouth of the Esmeraldas river there is a deposit of marine clay six or eight feet thick underlying the surface soil in a continuous stratum. Under this again is a horizon of sand and loam containing rude stone implements, and what is significant, fragments of rough pottery and gold ornaments.11 This shows conclusively that an extensive and prolonged subsidence took place in that locality not only after man reached there, but after he had developed the important art of the manufacture of clay vessels. This was certainly not at the beginning of his appearance on the scene; and the theory of any vast antiquity for such relics is not tenable.
The lowest, that is, the oldest, deposit on the eastern coast in which any relics of human industry are claimed to have been found, is that known as the “Columbian gravel.” This is considered by geologists to have been formed in the height of the first glacial period. From its undisturbed layers have been exhumed stones bearing the marks of rough shaping, so as to serve the purpose of rude primitive weapons.12
During the first or main Inter-glacial Period was deposited the “modified drift.” In a terrace of this material on the Mississippi, near Little Falls, Minnesota, Miss Babbitt found numerous quartz chips regarded by competent archæologists as artificial products.13 They represent the refuse of an early workshop near the quartz veins in that vicinity, and were cast aside by the pristine implement-maker when the Minnesota glacier was receding for the last time, but still lifted its icy walls five or ten miles above the present site of Little Falls.
The extensive beds of loess which cover many thousand square miles in the Central United States are referred to the second Glacial Epoch. Professor Aughey reports the finding of rudely chipped arrowhead in this loess as it occurs in the Missouri Valley. They lay immediately beneath the vertebra of an elephant, an animal, I need scarcely add, long since extinct. Another proof of man’s presence about that date is a primitive hearth discovered in digging a well along the old beach of Lake Ontario. According to that competent geologist, Professor Gilbert, this dated