74 Charles Darwin. 



with the evidences of change that were apparent on 

 every hand. The remains which he found showed 

 that in the past the country was peopled with a race 

 of giants which had given way to pigmies. The land 

 which once trembled under the tread of the huge 

 sloth, and saw the monster armadillo, was now 

 roamed by the little guanaco. Darwin proved that 

 the huge forms were contemporaneous with the 

 shells which then flourished in the ocean, conse- 

 quently were of comparatively recent date. What, 

 then, was the cause of their extinction ? Darwin's 

 first thought, and a most natural one, was that some 

 great cataclysm had taken place which destroyed 

 entire races in Patagonia and Brazil. He argued 

 from the results of his investigations that all the 

 physical features were the result of gradual changes, 

 consequently it could not have been a change of 

 temperature at once sudden and death-dealing. Many 

 of the animals which passed away so mysteriously 

 existed after the ice age, which has been supposed to 

 have been the exterminator. What, then, could 

 have been the cause of such widespread destruction ? 

 That early man might have been the destroyer 

 evidently passed through the mind of the young 

 naturalist, as he says : " Did man, after his first in- 

 road into South America, destroy, as has been 

 suggested, the unwieldy Megatherium and the other 

 Edentata ? " 



Yet he believed the extinction of the smaller 

 forms, as the little tucutuco, could not have been 

 effected in this way. He considered an extreme 

 drought and reflected upon its possibilities, also 



