174 CAUSES OF EXTINCTION. [chap. vm. 



sistibly hurried into the belief of some great catastrophe ; but 

 thus to destroy animals, both large and small, in Southern Pata- 

 gonia, in Brazil, on the Cordillera of Peru, in North America 

 up to Behring's Straits, we must shake the entire framework oi 

 the globe. An examination, moreover, of the geology of La 

 Plata and Patagonia, leads to the belief that all the features of 

 the land result from slow and gradual changes. It appears from 

 the character of the fossils in Europe, Asia, Australia, and in 

 North and South America, that those conditions which favour 

 the life of the larger quadrupeds were lately co-extensive with 

 the world : what those conditions were, no one has yet even 

 conjectured. It could hardly have been a change of tempera- 

 ture, which at about the same time destroyed the inhabitants of 

 tropical, temperate, and arctic latitudes on both sides of the 

 globe. In North America we positively know from Mr. Lyell, 

 that the large quadrupeds lived subsequently to that period, when 

 boulders were brought into latitudes at which icebergs now never 

 arrive : from conclusive but indirect reasons we may feel sure, 

 that in the southern hemisphere the Macrauchenia, also, lived 

 long subsequently to the ice-transporting boulder-period. Did 

 man, after his first inroad into South America, destroy, as lias 

 been suggested, the unwieldy Megatherium and the other Eden- 

 tata ? We must at least look to some other cause for the destruc- 

 tion of the little tucutuco at Bahia Blanca, and of the many 

 fossil mice and other small quadrupeds in Brazil. No one 

 will imagine that a drought, even far severer than those which 

 i^ause sucli losses in the provinces of La Plata, could destroy 

 every individual of every species from Southern Patagonia to 

 Behring's Straits. What shall we say of the extinction of the 

 horse ? Did those plains fail of pasture, which have since been 

 overrun by thousands and hundreds of thousands of the descend- 

 ants of the stock introduced by the Spaniards ? Have the subse- 

 quently introduced species consumed the food of the great ante- 

 cedent races ? Can we believe that the Capybara has taken the 

 food of the Toxodon, the Guanaco of the Macrauchenia, the ex- 

 isting small Edentata of their numerous gigantic prototypes? 

 Certainly, no fact in the long history of the world is so startling 

 as the wide and repeated exterminations of its inhabitants. 

 Nevertheless, if we consider the subject under another point of 



