108 BAIIIA BLANCA. 



level of higli-water ; and lience the elevation of the 

 land has been small (without there has been an in- 

 tercalated period of subsidence, of which we have 

 no evidence) since the great quadrupeds wandered 

 over the surrounding plains ; and the external fea- 

 tures of the country must then have been very 

 nearly the same as now. What, it may natural- 

 ly be asked, was the character of the vegetation at 

 that period ; was the country as wretchedly sterile 

 as it now is 1 As so many of the co-embedded 

 shells are the same with those now living in the 

 bay, I was at first inclined to think that the former 

 vegetation was probably similar to the existing one ; 

 but this would have been an eiToneous inference, 

 for some of these same shells live on the luxuriant 

 coast of Brazil ; and generally, the character of the 

 inhabitants of the sea are useless as guides to judge 

 of those on the land. Nevertheless, from the fol- 

 lowing considerations, I do not believe that the 

 simple fact of many gigantic quadnipeds having 

 lived on the plains round Bahia Blanca is any sure 

 guide that they formerly were clothed with a luxvi- 

 riant vegetation : I have no doubt that the sterile 

 countiy a little southward, near the Rio Negro, 

 with its scattered thomy trees, would support many 

 and large quadrupeds. 



That large animals require a luxuriant vegeta- 

 tion, has been a general assumption which has 

 passed from one work to another; but I do not 

 hesitate to say that it is completely false, and that 

 it has vitiated the reasoning of geologists on some 

 points of great interest in the ancient history of the 

 world. The prejudice has probably been derived 

 from India and the Indian islands, where troops 

 of elephants, noble forests, and impenetrable jun- 

 gles are associated together in every one's mind. 



