From that moment the era of migrations to America was opened. It has never been closed since. Every year the winter rebuilds the bridge which connects East Cape with Cape Prince of Wales; every year a road, comparatively easy for hardy pedestrians, stretches from one continent to the other; and we know that the coast populations of the opposite shores take advantage of it to maintain relations.
Is it not evident that, whenever one of those great movements which we know have agitated Asia made its shocks felt away in distant countries, whenever political or social revolutions overwhelmed them, fugitive or conquered people would have taken this route, of the existence of which they were aware? To get rid of the idea of migrations over the frozen sea, we should have to assume that all the corresponding regions have enjoyed a perpetual peace from the beginning of Quaternary times; but such a peace, you know, is not of this world.
This sea can have been only the principal route followed by the American immigrations. Farther south, the chain formed by the Aleutian Islands and Alaska opens a second route to tribes which have a little skill in navigation. The Aleuts occupy, in Dall's ethnological chart, the whole extremity of the peninsula. By these ways may have taken place what we might call the normal peopling of America. But, bathed on either side by a great ocean, that continent could not fail to profit by the chances of navigation; and we perceive more and more how this must have been the case. We are now justified in saying that Europe and Africa on one side, and Asia and Oceania on the other, have sent to America a number of involuntary colonists, more considerable, probably, than one would be ready to suppose.
The immigrations, in America as in Europe, have been intermittent, and separated sometimes by centuries. America has been peopled as if by a great human river, which, rising in Asia, has traversed the continent from north to south, receiving along its course a few small tributaries. This river resembles the torrent streams of which we have examples in France. Usually, and occasionally for years at a time, their bed is nearly dry. Then some great storm comes, and a liquid avalanche descends from the mountains where their sources lie, covers and ravages the plain, turning over the ancient alluviums, stirring up and mixing the old and new materials, and carrying farther each time the débris it has torn up on its passage. Like this has been the career of our ethnological river. Its floods have, besides, often been diverted to the right or left, and it has opened new derivations. It has also had its eddies. But its general direction has not changed, and we can trace it down to the present.
One of the highest tasks of Americanists will be to ascend to