PRESENT AND PAST. 1?I 



The Relation of the Present to the Past. 

 Speaking in general terms, it is found that the 

 species of the most recent geological deposits are 

 identical with those now living, although there are, of 

 course, thousands of species now living which have 

 never been found as fossils. Rocks somewhat older 

 contain fossils related to existing forms, but specifi- 

 cally distinct ; and going still farther back, the rela- 

 tions become less and less close, until finally we 

 reach a fauna very different from that existing to- 

 day. All of this is, of course, compatible with any 

 theory of the organic world that we may form, 

 agreeing equally well with special creation or with 

 evolution. But when closely examined the facts are 

 more significant. If the fossils of any one locality, 

 sufficiently isolated to prevent free migration, be 

 compared with its living animals, a striking likeness 

 is seen. For example : it is found that the fauna 

 of South America is peculiar in possessing a great 

 number of the remarkable order of Edentata (arma- 

 dillos, etc.), animals found nowhere else in the world, 

 with the exception of one quite different form in 

 Africa. Now the fossils of North and South Amer- 

 ica are also remarkable in possessing great numbers of 

 Edentates, which will therefore naturally be looked 

 upon as the ancestors of the present species. An- 

 other illustration is offered by the primates of the 

 New and the Old worlds. The New-World monkeys 

 are very different from those of the old world, al- 

 though, so far as we can see, there is no reason for this 

 in the physical conditions of the two worlds; but the 

 species of the one locality form a very distinct group, 



