362 ZOOLOGICAL GEOGRAPHY. [part hi. 



and Malaya to have taken place, we shall perhaps be able to 

 account for most of the special affinities they present, with the 

 least amount of simultaneous elevation of the ocean bed ; which 

 it must always be remembered, requires a corresponding de- 

 pression elsewhere to balance it. 



Concluding Remarks on the Oriental Region. — We have already 

 so fully discussed the internal and external relations of the 

 several sub-regions, that little more need be said. The rich and 

 varied fauna which inhabited Europe at the dawn of the ter- 

 tiary period, — as shown by the abundant remains of mammalia 

 wherever suitable deposits of Eocene age have been discovered, — 

 proves, that an extensive Palsearctic continent then existed ; 

 and the character of the flora and fauna of the Eocene deposits 

 is so completely tropical, that we may be sure there was then no 

 barrier of climate between it and the Oriental region. At that 

 early period the northern plains of Asia were probably under 

 water, while the great Thibetan plateau and the Himalayan range, 

 had not risen to more than a moderate height, and would have 

 supported a luxuriant sub-tropical flora and fauna. The Upper 

 Miocene deposits of northern and central India, and Burmah, 

 agree in their mammalian remains with those of central and 

 southern Europe, while closely allied forms of elephant, hyaena, 

 tapir, rhinoceros, and Chalicotherium have occurred in North 

 China; leading us to conclude that one great fauna then 

 extended over much of the Oriental and Palrearctic regions. 

 Perim island at the mouth of the Eed Sea, where similar 

 remains are found, probably shows the southern boundary of 

 this part of the old Palrearctic region in the Miocene period. 

 Towards the equator there would, of course, be some peculiar 

 groups ; but we can hardly doubt, that, in that wonderful time 

 when even the lands that stretched out furthest towards the 

 pole, supported a luxuriant forest vegetation, substantially one 

 fauna ranged over the whole of the great eastern continent of the 

 northern hemisphere. During the Pliocene period, however, a 

 progressive change went on which resulted in the complete 

 differentiation of the Oriental and Palrearctic faunas. The 



