EVIDENCE FROM DISTRIBUTION 135 



that time of isolation, we find, as already stated, 

 that they are totally distinct from their contem- 

 poraries of the north. The rocks of Patagonia and 

 Argentina have proved to be quite as marvellous a 

 museum of vanished mammalian life as those of the 

 western United States and they tell the story of 

 origins and migrations with the greatest clearness. 

 The older Miocene rocks of Patagonia have already 

 yielded to the zealous collector a great host of 

 beautifully preserved mammalian remains, among 

 which cannot be found a single one that was ancestral 

 to any of the mammals of the second category, 

 which, on other grounds, we concluded to have been 

 derived from the north. On the other hand, we find 

 the ancestors of nearly all the peculiarly South 

 American forms, except those which, there is reason 

 to believe, never ranged so far south as Patagonia. 

 There was a great abundance of hoofed animals, 

 but they all belonged to orders which have long been 

 extinct, and there were many beasts of prey, large 

 and small, but they were not true Carnivora, but 

 rather resembled the predaceous marsupials of 

 Australia. South America suffered even more from 

 the Pleistocene extinctions than did North America 

 and lost not only many indigenous orders, such as 

 the ground sloths and glyptodonts, of which there 

 was an incredible variety, and the native hoofed 

 animals, but also several of the immigrants as well, 

 such as the mastodons, horses and antelopes, the 

 great sabre-tooth tigers and short-faced bears. 



