Although the access to the continent of North America is much more easily had upon its western side, and though all the early settlements were probably made that way, the configuration of the land is such that it is not possible to get easy access to the heart of the continent from the Pacific shore. So that although the Atlantic Ocean was most forbidding and difficult as a way to America, once passed, it gave the freest and best access to the body of the continent. In the west, the Cordilleras are a formidable bar to those who seek to enter the continent from the Pacific. None but a modern civilization would ever have forced its barriers of mountains and of deserts. An ancient civilization, if it had penetrated America from the west, would have recoiled from the labor of traversing this mountain system, that combines the difficulties of the Alps and the Sahara. If European emigration had found such a mountain system on the eastern face of the continent, the history of America would have been very different. Scarcely any other continent offers such easy ingress as does this continent to those who come to it from the Atlantic side. The valleys of the St. Lawrence, the Hudson, the Mississippi, in a fashion also of the Susquehanna and the James, break through or pass around the low-coast mountains, and afford free ways into the whole of the interior that is attractive to European peoples. No part of the Alleghanian system presents any insuperable obstacles to those who seek to penetrate the inner lands. The whole of its surface is fit for human uses; there are neither deserts of sand nor of snow. The axe alone would open ways readily passable to men and horses. So that when the early settlers had passed the sea, all their formidable geographical difficulties were at an end,—with but little further toil the wide land lay open to them. I propose in the subsequent pages to give a sketch of the physical conditions of this continent, with reference to the transplanted civilization that has developed upon its soil. It will be impossible, within the limits of this essay, to do more than indicate these conditions in a very general way, for the details of the subject would constitute a work in itself. It will be most profitable for us first to glance at the general relations of climate and soil that are found in North America, so far as these features bear upon the history of the immigration it has received from Europe.