THE PAL^EARCTIC REGION 



19: 



Chinese Sub-region 



Section VII. — The Past History of the 

 Palsearctic Mammal-fauna 



Although the pakeontological history of Europe, so far 

 as it has been worked out, has been very thoroughly in- 

 vestigated, our knowledge of its extinct mammals, at any 

 rate, is not to be compared with that which has been 

 acquired in the Nearctic Region. This is probably due, to 

 a great extent, to the comparative rarity on this side of 

 the Atlantic of fresh-water lake deposits, the examination 

 of which, in North America, has produced such astonishing 

 results. 



Passing over the Mesozoic Mammals, which throw very 

 little light on any of the problems involved in the present 

 case, we find in the earliest Eocene beds scanty remains of 

 a fauna containing hardly any members of the existing 

 orders of Mammals. In their place is a series of forms 

 closely resembling one another in possessing five-toed and 



