250 DALY. 



Again, the structure of recently elevated coral islands, as described 

 by many expert observers, favors the new theory, while it casts serious 

 doubt on the theory of Darwin and Dana. Though the comparatively 

 recent elevation has amounted to 100 m. or more in the Solomon 

 islands, Fiji islands, the Tonga archipelago, etc., no case of a massive 

 reef more than 60 m. thick seems to have been demonstrated in the 

 island slopes so exposed. The raised reefs are described as having 

 thicknesses less than 60 m., and they commonly, if not always, lie 

 unconformably on rocks of other character. The structural uncon- 

 formity thus matches the topographic unconformity of non-elevated 

 reefs with their respective platforms. In both structural relation 

 and thickness the uplifted reefs show features demanded by the Glacial- 

 control theory. According to the older submergence theory, these 

 reefs should have no definite limit of thickness or show systematic 

 unconformity with their basements. 



In a similar way the many elements of the new theory have been 

 discussed. The survey of the field is not exhaustive and the problem 

 needs attack from those more competent than the writer to value these 

 different elements. Since a series of qucmtitics, either fixed or lying 

 within narrow, definite limits, are absolutely essential to the theory, 

 its final testing is comparatively an easy matter. It may be observed 

 that it is favored by Mayer, one of the investigators now most actively 

 engaged in the field study of coral reefs. ''^ His working colleague, 

 Vaughan, has also concluded that a recent rise of sea-level, due to 

 deglaciation, must be regarded as a leading fact in the explanation of 

 existing reefs. He also WTites, concerning the West Indian reefs: 

 "In every instance the coral reefs or reef corals have developed on 

 platform basements which owe their origin to geologic agencies other 

 than those dependent on the presence of corals." ^^ 



The writer offers no apology for entering the coral-reef controversy. 

 The facts show that the problem cannot be solved merely and only 

 from the data secured by intensive study of the reefs themselves. 

 The dominant submarine feature of the coral seas is not the reef but 

 the plateau. The abundant, reliable observations on the reefs, al- 

 ready published by zoological and other experts, carry most of the 

 relevant facts, but the chief topographic data are to be found in the 

 Admiralty charts of the governments. A life-time spent in a personal 

 study of the reefs would add little to the easily accessible bathometric 



78 A. G. Mayer, Pop. Sci. Monthly, Sept., p. 215 (1914). 



79 T. W. Vaughan, Science, 41, 508 (1915). 



