Darwirts Theory of Coral Reefs. 183 



it is, bad no place in geology or geography at the time of 

 Dana's voyage. He appears to have been the first fully 

 to recognize, and be was surely the first to state with 

 emphasis, the simple origin of the alternating bays and head- 

 lands in an irregular shoreline by the partial submergence of a 

 dissected land-mass. He may have been preceded a few years 

 in the general recognition of the idea by De la Beche, who in 

 his "Researches in Theoretical Geology" (London, J 831) 

 states that, on the island of Corsica, "the west coast plunges 

 suddenly into the sea, and the valleys are continued beneath 

 it, presenting numerous inlets where the level of the sea meets 

 the inclined bottom of the valley " (p. 193) : De la Beche's 

 attention was, however, given chiefly to the submarine part of 

 the valleys, and only incidentally to the associated outline of 

 the coast. ~No one, I believe, has hitherto quoted the above sen- 

 tence in this connection : in Penck's thorough review of coastal 

 forms in his " Morphologie der Erdoberflache " (Stuttgart, 

 1894), reference is made to De la Beche's discussion of sub- 

 merged valleys, but Dana is named as the first to recognize the 

 origin of bays by submergence (582). ' 



Dana, on the other hand, explicitly and repeatedly emphasizes 

 the effect of subsidence in producing bays, and as repeatedly 

 adduces indented shore lines in confirmation of Darwin's 

 theory of coral reefs. In his first report he says,* when ex- 

 plaining the consequences of subsidence : " The very features 

 of the land, the deep indentations, are sufficient evidence of 

 subsidence to one who has studied the character of the Pacific 

 islands," and in a footnote he refers to a later chapter where 

 the following explicit statement is made, under the general 

 heading, " Evidence of subsidence," and the special heading, 

 " Deep bay-indentations in coasts as the terminations of 

 valleys " : " In the remarks upon the valleys of the Pacific 

 islands, it has been shown that they were in general formed by 

 the waters of the land, unaided by the sea ; that the sea tends 

 only to level off the coast, or give it an even outline. When, 

 therefore, we find the several valleys continued on beneath the 

 sea, and their enclosing ridges standing out in long narrow 

 points, there is reason to expect that the island has subsided 

 after the formation of the valleys. For such an island as 

 Tahiti could not subside even a few scores of feet without 

 changing the even outline into one of deep coves or bays, the 

 ridges projecting out to sea on every side. . . . The absence of 

 such coves, on the contrary, is evidence that any subsidence 

 which has taken place has been comparatively small in 

 amount " (393). A similar statement is made in Dana's first 



* Geology, U. S. Expl. Exped., 1849, 131. 



