﻿Vol. 6 1.] DOLOMITES OE SOTJTHEKN TYROL. 99 



The opponents of the coral-reef theory state that : — 



(1) The general absence of corals in the dolomite militates against 



the coral-reef hypothesis. Calcareous algae and echino- 

 derms, bnt not corals, are the most common fossils. 



(2) The apparent thinning-out of the dolomite into marls and ashes 



is due to faulting, while the Schlern Dolomite really succeeds 

 the St. Cassian Marls, and does not pass laterally into them. 



(3) The reef-like shape of the masses is a structural feature due 



also to faulting. 



In view of the large amount of work dpne within the last 10 

 years in the exploration of recent coral-reefs, and the examination 

 of the materials of which they are composed, it may serve a useful 

 purpose to enquire if the results obtained are of such a character as 

 may prove helpful in determining the question whether the dolomite- 

 mountains do or do not represent old coral-reefs. 



The researches of Prof. Alexander Agassiz in many parts of the 

 Atlantic, Indian, and Pacific Oceans, the expedition to Christmas 

 Island under Dr. C. "W. Andrews, 1 and to the eastern group of the 

 Fiji Islands under Mr. E. C. Andrews of Sydney University, 2 have 

 added largely to our knowledge of the structure and origin of up- 

 raised coral-islands. Mr. J. Stanley Gardiner has put on record his 

 observations at Funafuti and in the Maldives 3 ; while the borings at 

 Funafuti in 1896 and 1897 (under the leadership of Prof. Sollas, and 

 afterwards of Prof. David) provided the means for the systematic 

 examination of the materials composing a typical atoll down to 

 a depth of 1114 feet. The Funafuti Report has recently (1904) 

 been published by the Royal Society. The chemical examination of 

 the cores was commenced by Dr. C. G. Cullis, and continued by 

 Mr. J. Hart-Smith and myself, under Prof. Judd ; and one of the 

 most interesting results obtained, apart from the highly-dolomitic 

 character of parts of the material, consisted in the discovery that 

 the rocks forming the cores were of extraordinary purity, being 

 practically free from insoluble residue. 



During the progress of the examination of the Funafuti materials, 

 I had an opportunity of making a chemical and microscopical 

 examination of the collection from the upraised mass of Christmas 

 Island, and of a selection from the collections of Prof. Agassiz, Prof. 

 David, and Mr. E. C. Andrews from the Fiji Islands and other parts 

 of the Pacific Ocean. The results obtained were published in June 

 1903, in vol. xlii of the ' Bulletin ' of the Museum of Comparative 

 Zoology at Harvard College. There I drew attention to the fact 

 that :— 



1 Geogr. Journ. vol. xiii (1899) pp. 17-35 (with map) & ' Monograph of 

 Christmas Island' Brit. Mus. (Nat. Hist.) 1900. 



2 Bull. Mus. Comp. Zool. vol. xxxviii (1900) pp. 1-50 & pis. i-xxxix. 



3 Proc. Camb. Phil. Soc. vol. ix (1898) pp. 417-503. 



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