272 OBITUARY X 



which a great deal might be done, beyond collect- 

 ing ; and it was while sitting beneath a low lava 

 cliff on the shore of this island, that a sense of his 

 real capability first dawned upon Darwin, and 

 prompted the ambition to write a book on the 

 geology of the various countries visited. (I. p. 66.) 

 Even at this early date, Darwin must have thought 

 much on geological topics, for he was already 

 convinced of the superiority of Lyell's views to 

 those entertained by the catastrophists l ; and his 

 subsequent study of the tertiary deposits and of the 

 terraced gravel beds of South America was 

 eminently fitted to strengthen that conviction. 

 The letters from South America contain little 

 reference to any scientific topic except geology ; 

 and even the theory of the formation of coral 

 reefs was prompted by the evidence of extensive 

 and gradual changes of level afforded by the 

 geology of South America ; " No other work of 

 mine," he says, " was begun in so deductive a spirit 

 as this ; for the whole theory was thought out on 

 the West Coast of South America, before I had 

 seen a true coral reef. I had, therefore, only to 

 verify and extend my views by a careful exam- 



1 "I had brought with me the first volume of Lyell's Principles 

 of Geology, which I studied attentively ; and the book was of 

 the highest service to me in many ways. The very first place 

 which I examined, namely, St. Jago, in the Cape de Verd 

 Islands, showed me clearly the wonderful superiority of Lyell's 

 manner of treating Geology, compared with that of any other 

 author whose works I had with me or ever afterwards 

 read" (I. p. 62.) 



