GEOLOGY AND PALEONTOLOGY OF THE CANAL ZONE. 



317 



probability soems distinctly in favor of their being submerged pla- 

 teau surfaces, upon which coral reefs, mostly marginal, have estab- 

 lished themselves during and subsequent to moderate submergence. 

 I will revert to Admiral Wharton's emphasis of the levelness of 

 the floors of atoll lagoons (depth 24 to 26 fathoms), to his statement, 

 "inside the low rim of growing coral which encircles their edges in 

 various degrees," and to his question "What causes this remarkable 

 similarity of depth and this extraordinarily even surface over these 

 large banks?" As I believe this short article by Admiral Wharton 

 is one of the truly great contributions to our knowledge of coral reefs, 



80 



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 Pedro 



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 Bank 



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 675 



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 Fig. 24.— Chart of Pedro bank: From U. S. hydrographic chart No. 1290. Scale 1 inch = 48 



nautical miles. 



the temptation to quote all of it is great. In it he points out one of 

 the fundamental defects of the Darwinian hypothesis, namely, that 

 the lagoon floor is not basin shaped as it should be if the atoll is due 

 to the upgrowth of a reef that began on the slopes of a volcanic cone. 

 He says: "I have no hesitation in saying that a flat floor is an 

 invariable characteristic of a large atoll, and I can not find his ' deeply 

 concave surface' in any large atoll. On the contrary, a flat surface 

 is found in all of these, whether the rim be above or below the surface." 

 Daly in his two papers cited has made an elaborate study of the 

 depths of atoll lagoons of the Pacific and Indian oceans and has com- 

 pared the depths in them with the depths in the lagoon channels of 

 the same region. As the data compiled by him can not be repeated 



