212 GEOGRAPHICAL DISTRIBUTION OF ANIMALS. 



rivers of the United States, peculiar species will be found in 

 each basin, associated with others which are common to 

 several basins. Thus, the Delaware River contains species 

 not found in the Hudson. But, on the other hand, the pick- 

 erel is found in both. Now, if all animals originated at one 

 point, and from a single stock, the pickerel must have passed 

 from the Delaware to. the Hudson, or vice versa, which it 

 could only have done by passing along the sea-shore, or by 

 leaping over large spaces of terra fir ma ; that is to say, in 

 both cases it would be necessary to do violence to its organi- 

 zation. Now, such a supposition is in direct opposition to 

 the immutability of the laws of Nature. 



450. We shall hereafter see that the same laws of distri- 

 bution are not limited to the actual creation only, but that 

 they have also ruled the creations of former geological 

 epochs, and that the fossil species have lived and died, most 

 of them, at the place where their remains are found. 



451. Even Man, although a cosmopolite, is subject, in a 

 certain sense, to this law of limitation. While he is every 

 where the one identical species, yet several races, marked 

 by certain peculiarities of features, are recognized ; such as 

 the Caucasian, Mongolian, and African races, of which we 

 are hereafter to speak. And it is not a little remarkable, 

 that the abiding places of these several races correspond 

 very nearly with some of the great zoological regions. 

 Thus we have a northern race, comprising the Samoyedes 

 in Asia, the Laplanders in Europe, and the Esquimaux in 

 America, corresponding to the arctic fauna, (400,) and, 

 like it, identical on the three continents, having for its 

 southern limit the region of trees, (422.) In Africa, we 

 have the Hottentot and Negro races, in the south and central 

 portions respectively, while the people of northern Africa 

 are allied to their neighbors in Europe ; just as we have 

 seen to be the case with the zoological fauna in general, 



