40 THE BERMUDA ISLANDS. 



cliffs already described were formed. ' With this conception 

 the atoll practically disappears, since, in the absence of atoll 

 characters, there is nothing to indicate that the structure was 

 ever present ; at any rate, its existence is rendered purely 

 hypothetical. 



Darwin discusses the subject with his usual perspicuity, and 

 finds reason to doubt that the islands are a true atoll. He 

 points out their close general resemblance to an atoll, but in- 

 dicates the following important differences: " first, in the mar- 

 gin of the reef not forming a flat, solid surface, laid bare at 

 low water, and regularly bounding the internal space of shal- 

 low water or lagoon ; secondly, in the border of gradually 

 shoaling water, nearly a mile and a half in width, which sur- 

 rounds the entire outside of the reef; and thirdly, in the size, 

 height, and extraordinary form of the islands, which present 

 little resemblance to the long, narrow, simple islets, seldom ex- 

 ceeding half a mile in breadth, which surmount the annular 

 reefs of almost all the atolls in the Indian and Pacific oceans." 

 The great height of the land, as compared with other islands, 

 is also commented upon. 2 



In all these characters the Bermudas unquestionably dif- 

 fer from a typical atoll, but allowing for the conditions which 

 Prof. Rice suggests these differences lose much of their signifi- 

 cance. They are not antagonistic to the notion of an overdone 

 atoll which is now undergoing destruction. But it is difficult^ 

 if not impossible, to demonstrate the atoll condition itself. 

 If it ever existed it has been completely masked by overgrowth, 

 for I believe the facts such as they are show with sufficient 

 clearness that the present islands and reefs have little or noth- 

 ing in common, beyond occupying position, with a pre-existent 

 ring. Matthew Jones has well argued 3 that a bodily uplift of 



1 Geol. of Bermuda. Bull. U. S. National Museum, No. 25, pp. 16-17. 



2 Structure and Distribution of Coral Reefs, 1842, p. 204. 



3 Nature, Aug. 1, 1872. 



