chap, vi.] MAMMALIA OF THE OLD WORLD. Ill 



the musk-sheep, and the woolly rhinoceros, are associated with 

 several other species of rhinoceros and elephant; with nume- 

 rous civets, now abundant only in warm countries ; and with 

 antelopes of several species. We also meet here with a great 

 extension of range of forms now limited to small areas. The 

 Saiga antelope of Eastern Europe occurs in France, where wild 

 sheep and goats and the chamois were then found, together with 

 several species of deer, of bear, and of hysena. A few extinct 

 genera even come down to this late period, such as the great 

 sabre-toothed tiger, Machairodus ; Galeotheriurn, a form of Viver- 

 ridse ; Palceospalax, allied to the mole ; and Trogontherium, a 

 gigantic form of beaver. 



We find then, that even at so early a stage of our inquiries we 

 meet with a problem in distribution by no means easy to solve. 

 How are we to explain the banishment from Europe in so short 

 a space of time (geologically speaking) of so many forms of life 

 now characteristic of warmer countries, and this too during a 

 period when the climate of Central Europe was itself becoming 

 warmer ? Such a change must almost certainly have been due 

 to changes of physical geography, which we shall be better able 

 to understand when we have examined the preceding Pliocene 

 period. We may here notice, however, that so far as we yet 

 know, this great recent change in the character of the fauna is 

 confined to the western part of the Palaearctic region. In caves 

 in the Altai Mountains examined by Prof. Brandt, a great col- 

 lection of fossil bones was discovered. These comprised the 

 Siberian rhinoceros and mammoth, and the cave hysena ; but all 

 the others, more than thirty distinct species, are now living in 

 or near the same regions. We may perhaps impute this dif- 

 ference to the fact that the migration of Southern types into 

 this part of Siberia was prevented by the great mountain and 

 desert barrier of the Central Asiatic plateau ; whereas in Europe 

 there was at this time a land connection with Africa. Post- 

 pHocene deposits and caverns in Algeria have yielded remains 

 resembling the more southern European types of the Post- 

 pliocene period, but without any admixture of Arctic forms; 

 showing, as we might expect, that the glacial cold did not 



