In America, however (where the Atlantic coast, at least, does not afford caverns like those of Western Europe), the evidence all goes to show that palaeolithic men were in continuous possession of the region from the time when they first appeared until driven northward by the Indians, perhaps close upon the retreat of the great glacier. Returning to the Abbott collection, we shall find that it contains a large quantity of rude arrow-points, scrapers, and other forms of stone implements, some of which are much better than any of the "turtle-backs" or other palaeoliths from the lower gravels. These are found in the upper part of the drift, resting upon them and buried in the humus _above_: in the latter position they are, of course, more or less intermixed with the jasper and quartz relics of the modern Indian; but these are always made of argillite, are ruder, are much weather-worn, and never occur in the "open-air workshops" of the Indians, where quantities of flint-flakes and unfinished implements of jasper and quartz and of superior pattern are found lying together within a limited space. These argillite points and scrapers seem to belong to the palaeolithic man toward the end of his "age," manifesting a higher stage of culture reached by gradual improvement. It thus appears that while in Europe the rude-stone age was divided into two eras,--the River-drift and the Cave,--in Eastern America the aboriginal Eskimos held sway without interruption, and slowly bettered themselves through unnumbered centuries, until at last they were driven into icy exile by merciless conquerors, where, no doubt, they lost much of the advancement they had gained under more gracious conditions.