276 ALEXANDER AGASSIZ 



supposing the process to continue until the island is sub- 

 merged. This new condition is represented by the dotted 

 lines. C C is the new sea level ; nothing remains but a 

 lagoon enclosed in a circle of coral reef, which might 

 later be built up to form a lagoon island. 



The beauty and simplicity of this theory of Darwin's 

 appealed to the layman as well as to the man of science ; 

 it was strengthened by the investigations of Dana, pub- 

 lished in 1849, who as naturalist accompanied Captain 

 Wilkes on his memorable voyage from 1838 to 1842. For 

 many years it remained unquestioned as the true ex- 

 planation of the causes that had led to the creation of 

 these curious formations. But this theory does not rest 

 on the patient investigations that characterize Darwin's 

 other work ; he himself says in his autobiography l that 

 it was formed before he even saw a coral reef. Keeling 

 was the only atoll on which he ever landed, and his 

 investigation of barrier reefs was limited to Mauritius 

 and Tahiti. Dana's observations, although more exten- 

 sive, appear to have been much curtailed by Wilkes's 

 fear that his distinguished companion would be eaten by 

 savages. 



Both Darwin and Dana, it may be noted, have assumed 

 a possibility as a fact, and the theory once given, have 

 attempted to prove the subsidence, instead of bringing 

 the subsidence of coral reefs in support of the theory. 

 Indeed, the advocates of Darwin's view have assumed 

 a subsidence from the existence of atolls in regions 

 where there are innumerable proofs of elevation. 



Gradually, a few men of science began to suspect that 

 the true explanation of the formation of coral reefs 

 might not be so simple. As early as the middle of the 



1 Life and Letters, vol. I, p. 58. 



