Zi2 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!; 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 «J 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.) 
