AGES OF NATURE. 203 



tion approaches yet more nearly to that of the present 

 epoch. Besides the Pachyderms, that were also predomi- 

 nant in the lower stage, we find numbers of carnivorous 

 animals, some of them much surpassing in size the lions 

 and tigers of our day. We meet also gigantic Edentata, 

 and Rodents of great size. 



493. The distribution of the Tertiary fossils also reveals 

 to us the important fact, that in this epoch, animals of the 

 same species were circumscribed in much narrower limits 

 than before. The earth's surface, highly diversified by 

 mountains and valleys, was divided into numerous basins, 

 which, like the Gulf of Mexico, or the Mediterranean of this 

 day, contained species not found elsewhere. Such was the 

 basin of Paris, that of London, and on this continent, that of 

 South Carolina. 



494. In this limitation of some types within certain bounds, 

 we distinctly observe another approach to the actual con- 

 dition of things, in the fact that certain groups of animals 

 which occur only in particular regions are found to have 

 already existed in the same regions during the Tertiary 

 epoch. Thus the Edentata are the predominant animals 

 in the fossil fauna of Brazil as well as in its actual fauna ; 

 and Marsupials were formerly as numerous in New Hol- 

 land as they now are, though in general of much larger size. 



495. THE MODERN EPOCH. Reign of Man. The 

 Present epoch succeeds to, but is not a continuation of, the 

 Tertiary age. These two epochs are separated by a great 

 geological event, traces of which we see everywhere around 

 us. The climate of the northern hemisphere, which had 

 been, during the Tertiary epoch, considerably warmer than 

 now, so as to allow of the growth of palm-trees in the tem- 

 perate zone of our time, became much colder at the end of 

 this period, causing the polar glaciers to advance south, much 

 beyond their previous limits. It was this ice, either floating 



