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XXIX. Origin of Coral Reefs and Islands. 

 By James D. Dana, LL.D. 



[Continued from p. 161,] 



Part II. — The Objections considered. 



THE objections to the Darwinian theory may be considered 

 in the following order : — 



I. Darwin's insufficient knowledge of the facts bearing on 

 the subject. 



II. Subsidence not ordinarily a fact, because methods of 

 producing barrier reefs and atolls have been brought forward 

 that do not require its aid. 



III. The occurrence of cases of elevation in regions of atolls 

 and barrier-reefs inconsistent with the subsidence-theory. 



IV. No ancient coral-reefs in the geological series have the 

 great thickness attributed by the subsidence-theory to modern 

 reefs. 



V. Other methods of explanation and their supporting 

 evidence. 



The adverse remarks directed against the idea of a sinking 

 continent in the Pacific as the initial condition in the coral-reef 

 subsidence are outside of the present discussion for the reason 

 stated on the first page of this paper. In the following pages 

 the objections are first explained, under the above-mentioned 

 heads, and then follow, in paragraphs lettered a, b, c, &c, the 

 writer's discussions of the several points. 



I. Darwin's Insufficient Knowledge of the Facts. 

 In the Address referred to in the opening page of this 

 article, Dr. Geikie, speaking of Darwin, observes : — " It 

 should be borne in mind that, compared with more recent 

 explorers, he did not enjoy large opportunities for investi- 

 gating coral-reefs." " He appears to have examined one 

 atoll, the Keeling Reef, and one barrier-reef, that of Tahiti." 

 " By a gradually widening circle of observations a series of 

 facts has been established which were either not known, or 

 only partially known, to Darwin." — The authors appealed to 

 {qv the views that are presented as a substitute for Darwin's 

 are Prof. Karl Semper, who has examined and described reefs 

 of the Pelew and Philippine Islands ; Dr. J. J. Rein, who 

 has published on the physical geography of the Bermudas ; 

 Prof. Alexander Agassiz, who has written on the Florida 

 reefs and others in that vicinity ; and Mr. John Murray, of 

 the l Challenger ' Expedition, whose investigations were made 

 at Tahiti : all able men in science, whether more learned or 

 Phil. Mag. S. 5. Vol. 20. No. 124. Sept. 1885. U 



