LIFE OF TERTIARY PERIOD 223 



terres, or bad lands, where slow denudation has carved out cliffs, 

 peaks, and columns of the most fantastic shapes and colours. This 

 same action has brought to light the remains of many extinct 

 animals, and the bones of the Dinocerata, from their great size, 

 naturally first attract the attention of the explorer." 



As regards the mental powers of these strange animals, 

 Professor Marsh says : 



" The brain-cavity of Uintatherium is perhaps the most remark- 

 able feature in this remarkable genus. It shows us that the brain 



FIG. 76. SKULL OF ARSINOITHERIUM ZITTELI. 

 From the Upper Eocene of the Fayoum, Egypt. One-twelfth nat. size. 

 (B.M. Guide.) 



was proportionately smaller than in any other known mammal, 

 recent or fossil, and even less than in some reptiles. It is, in fact, 

 the most reptilian brain in any known mammal. In U. mirabile 

 (one of the large - tusked, horned species) it could apparently 

 have been drawn through the neural canal of all the presacral 

 vertebrae." 



