DARWIN AND WALLACE 29 



madillo. One evening, seated alone in the broad 

 expanse of the pampas, the idea suddenly swept over 

 him, stimulated, of course, by his study of Lyell : 

 "Can it be that the little armadillo and the sloth of 

 to-day are the degenerate descendants of the enormous ^ 

 megatherium and glyptodon of the past?" But his 

 mind was not yet ready to accept so bold an idea and 

 he swept it aside. 



The people of this wild neighborhood interested 

 Darwin very greatly, and he describes them with care. 

 In this connection a charming trait of Darwin's char- 

 acter comes beautifully in evidence. The absolute 

 purity of his mind, his utter freedom from grossness, 

 shows clearly in his account of the first really semi- 

 civilized people he had ever seen. 



A little later, while exploring Patagonia, Darwin 

 noticed the terrace-like formation of that desolate 

 country. A flat near the sea was succeeded by a 

 rapid rise, then came another flat. Three of these 

 terraces in succession stretch back toward the An- 

 des. At the base of the hi2:h terraces Darwin found 

 marine shells, largely similar to those of the ocean ^ 

 beach so many miles to the east. His study of Lycll 

 led him to suspect at once that this portion of South 

 America had been raised in successive stages out of 

 the bed of the Pacific. When they passed around 

 Cape Horn and up the western coast he hunted for 



