We say in general, for there are some animals, such as birds, that might easily fly across the ocean, and sea-weeds, that might drift across, and polar animals, such as bears, seals, foxes and dogs, and the like, which go and come as they will, all over the Arctic seas, that were found common to both worlds. With a moderate number of exceptions such as these, however, the plants and animals found in America proved on examination to be entirely new.

By the fauna of a country is meant the system of animals that inhabit it. The flora is its system of plants. Now, inasmuch as both the fauna and the flora of America were so essentially different from those of the old world, that, so far as could be judged from all that was known of the propagation of plants and animals, and of the changes which they may undergo from the influence of climate and soil, and other conditions, the one system, in the opinion of naturalists, could not have been produced from the other, it seemed to be wholly useless to attempt to contrive means by which the progenitors of the present races in America could have been wafted across the ocean, or could have migrated by means of countries and territories which once existed, but are now submerged.

Man Admitted to be an Exception

This reasoning, however, applied only to plants and to inferior animals, but not to man; for the races of men found upon this continent were deemed by naturalists to be of the same species with all the other races now existing in the world: that is, too difference between the different races of men were judged to be not specific differences, that is, not such as to preclude the possibility of their all being deduced from one original pair. This has always been the general opinion among naturalists, and in their systems of classification all the various races of men are classed as one species.