LIFE ON THE EARTH. 171 



not quite confined to that region, are more plentiful 

 there than elsewhere, and are successors of fossil 

 races also found almost exclusively in that country. 

 Thus the fossil Megatherium has been compared with 

 the Sloth, the Glyptodon with the Armadillo ; nor 

 does the enormous bulk of the fossils hinder the re- 

 ception of them into the same natural families. The 

 same lands then have been in successive periods 

 peopled by analogous races, and thus we have mani- 

 fested ' a wonderful relationship on the same conti- 

 nent between the dead and the living 1 .' Still this 

 succession of similar forms is limited to Csenozoic 



One other example must suffice. The marsupial 

 peculiarity of Australian Mammalia is not of modern 

 date ; the Australian caves contain evidence of the 

 same character in the races whose remains are there 

 preserved. The peculiarity indeed is of far earlier 

 origin, for it occurs in the Eocene deposits of the 

 basin of Paris, in the Lacustrine deposits over the 

 upper Oolite in Purbeck, in the lagoon of the great 

 Oolite at Stonesfield, and probably in the Trias of 



1 Darwin. This author does not suppose the living Edentata 



of the same region to be the dwarfed descendants of these mon- 



* strous beasts, but speaks of some others, their contemporaries in 



time and companions in the same caverns, which may be regarded 



as the progenitors of the living species. 



