The uniformity in their mode of living, I also assigned for the little variety to be found in the natives of America. As they were all savage, or recently civilized, they all lived in the same manner. In supposing that they had all one common origin, they were dispersed, without being intermixed; each family formed a nation not only similar to itself, but to all about them, because their climate and food were nearly similar; and as they had no opportunity either to degenerate or improve, so they could not but remain constantly and almost universally the same.
That their origin is the same with our own, I doubt not, independent of theological arguments; and from the resemblance of the savages of North America to the Oriental Tartars, there is reason to suppose they originally sprung from the same source. The new discoveries by the Russians, on the other side of Kamtschatka, of several lands and islands which extend nearly to the Western Continent of America, would leave no doubt as to the possibility of the communication, if these discoveries were properly authenticated, and the lands were in any degree contiguous. But, even in the supposition of considerable intervals of sea, is it not possible that there might have been men who crossed them in search of new regions, or were driven upon them by bad tempests? Between the Mariana islands and Japan there is, perhaps, a greater interval of sea than between any of the territories beyond Kamtschatka and those of America; and yet the Mariana islands were peopled with inhabitants who could have come from no part but from the Eastern Continent. I am inclined to believe, therefore, that the first men who set foot on America landed on some spot north-west of California; that the excessive cold of this climate obliged them to remove to the more southern parts of their new abode; that at first they settled in Mexico and Peru, from whence they afterwards diffused themselves over all the different parts of North and South America. Mexico and Peru must be considered as the most ancient inhabited territories of this continent, being not only the most elevated, but also the only ones in which the inhabitants were found connected together in society.