CORAL REEFS. APPENDIX. 229 



they go, point to a former direct land-connection across what 

 is now an arm of the Gulf. 



J. D. Dana. " Points in the Geological History of the Islands of Maui and Oahu." 

 Am. Journ. Science, 3d ser., xxxvii, 1889. 



The author gives the results of artesian borings made on 

 Oahu (Sandwich Islands) which indicate the presence of coral- 

 rock at depths varying from 500 feet or less to upwards of 1000 

 feet beneath the level of the sea. In Mr. Campbell's well, west 

 foot of Diamond Head, a continuous bed of coral, 505 feet in 

 thickness, was struck at a depth of 320 feet. The species of 

 coral found in these deep rocks not having been determined, 

 Prof. Dana holds that some doubt may yet be entertained as 

 to the beds in question affording positive proofs of subsidence, 

 although there is a strong probability favoring this view. It 

 is interesting to note in this connection that in the deep well 

 above noted a soapstone-like rock, 20 feet in thickness, was 

 found immediately underlying the basal bed of coral at a depth 

 of 1048 feet. Is this the correspondent of the soapstone-like 

 beds which Mr. Guppy found at many points underlying the 

 coral limestone of the Solomon Islands, and which that in- 

 vestigator considered to be evidence in favor of the view that 

 corals began to grow upward from great depths? This point 

 is fully discussed in the review of Mr. Guppy's papers. 



R. von Lendenfeld. A review of Mr. Bourne's paper on the Diego Garcia Reef. 

 N.iturwissenschaftliche Rundschau, Oct. 13, 1888. 



The author finds no facts either in this paper, or in the 

 papers of Murray, Agassiz, and Guppy, which are opposed to 

 the theory of subsidence. He justly calls attention to the low- 

 level of coral islands generally, which is opposed to any theory 

 of the progressive elevation of the ocean bottom. The great 

 development of the dolomite reefs of southern Tyrol (of the 

 Rha^tic period), such as the Langkofel, are cited in evidence 

 against the assumed non-existence of thick coral limestones in 

 any of the older geological formations. 



It is important to note in this connection the observation by 

 Suess that nowhere in the Gosau deposits, nor in the coralifer- 



