38 GEOLOGY AND HISTORY 



were no doubt also climatal changes in the course of 

 the age, which may have tended to the remarkable 

 mixture of animal types in its deposits. In connec- 

 tion with this there is now every reason to believe that 

 while, in its earlier part, the palanthropic age was 

 distinguished by a warm climate, in its later portion 

 a colder and more inclement atmosphere crept over 

 the northern hemisphere. As an illustration of this, 

 it is known that in the earlier part of the period a 

 noble species of elephant named Elephas antiquus, 

 and a rhinoceros (R. Merkii\ abounded in Europe ; 

 but as the age advanced these species disappeared, 

 and were replaced by the mammoth (E. primigenius) 

 and the woolly rhinoceros (R. tichorhinus\ animals 

 clothed like the musk-ox in dense wool and hair, and 

 evidently intended for a rigorous climate. With and 

 succeeding these last species, the reindeer becomes 

 characteristic and abundant. It is, as we shall see, a 

 point of much importance in what may be called the 

 prehistoric history of man, that he was introduced in 

 a period of genial temperature as well as of wide 

 continental extension, and survived to find his physi- 

 cal environment gradually becoming less favourable, 

 and the age ending in that great cataclysm which 

 swept so many species of animals and tribes of 

 men out of existence, and reduced the dry land of 

 our continents to its present comparatively limited 

 area. 



I should, perhaps, have noticed here the worked 

 flints found so abundantly in some parts of the south 



