Darwin's Theory of Coral Reefs. 185 



that a theory, even if it is well recommended by explaining 



the things it was invented to explain, still needs confirmation 

 by independent and unexpected evidence before it deserves to 

 be accepted as " demonstrated " ? 



But the most curious feature in all this discussion is that 

 Darwin himself did not announce in the second edition of his 

 " Coral Reefs," Dana's confirmatory evidence of the theory of 

 subsidence that had been published in the first edition of this 

 famous book. Darwin was so open-minded, so fair-minded, so 

 scrupulously careful in considering all sides of a problem, that 

 his failure to bring forward Dana's evidence can only mean 

 that he did not understand it. This is the more remarkable 

 when one re-reads his " Coral Reefs " attentively, and notes 

 the critical and impartial consideration that he gave, not only 

 to his own theory of subsidence but to various other theories, 

 and the thoroughness with which he deduced their consequences 

 for confrontation with the facts. He examined the volcanic 

 crater theory of atolls and dismissed it because it seemed 

 "improbable that there should have existed as many craters of 

 immense size crowded together beneath the sea, as there are 

 now in some parts atolls. . . Nevertheless," he adds, " if the 

 rim of a crater afforded a basis at the proper depth, I am far 

 from denying that a reef like a perfectly characterized atoll 

 might not be formed ; some such, perhaps, now exist." * 

 Agassiz reports reefs of this kind in the eastern archipelago 

 of the Fiji group. Darwin carefully considered the submarine 

 bank theory and recognized a certain value in it ; he wrote, 

 if "corals were to grow up from a bank with a level surface 

 some fathoms submerged, having steep sides and being situated 

 in a deep sea, a reef not to be distinguished from an atoll 

 might be formed ; I believe some such exist in the West 

 Indies. But a difficulty of the same kind with that affecting 

 the crater theory renders . . . this view inapplicable to the 

 greater number of atolls" (89 ; also 55). Even the newer in- 

 formation adduced by Murray as to the shower of organic 

 material that falls on the sea floor has not altogether relieved 

 this difficulty. Darwin explicitly, though briefh T , considered 

 complicated cases of elevation succeeding subsidence, and of 

 subsidence succeeding elevation (140, 145); he recognizes such 

 complications as interruptions in subsidence : "At the Society 

 archipelago . . . the shoalness of the lagoon channels . . . and 

 the broad belt of low land at the foot of the mountains indicate 

 that, although there must have been great subsidence to have 

 produced the barrier reefs, there has since elapsed a long 

 stationary period" (128). He makes repeated mention of 

 uplifted reefs of various kinds, and considers in some detail 



* "Coral Keefs," 1842, 89. 



Am. Jour. Sci.— Fourth Series, Vol. XXXV, No. 206.— February, 1913. 

 13 



