AGES OF NATURE. 235 



492. The fauna of the upper stage of the Tertiary forma- 

 tion approaches yet more nearly to that of the present epoch. 

 Besides the Pachyderms, that were also predominant 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 certain types within certain 

 bounds, we distinctly observe another approach to the present 

 condition of things, in the fact that 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 present fauna ; and Marsupials were 

 formerly as numerous in New Holland 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 every where 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 temperate zone of 

 our time, became much colder at the end of this period, 

 causing the polar glaciers to advance south, much beyond 



