166 Agassis — Tertiary Elevated Limestone Reefs of Fiji. 



as Totoya, Kimbombo, Wakava, Makongai, Moala, Nairai, 

 Ngau and otliers. In both cases the platform upon the top of 

 which the corals grow has been prepared by extensive sub- 

 marine erosion dating from the time when the limestones were 

 elevated by the volcanic rocks which crop out everywhere in 



Fi .i L 



Professor David, of the University of Sydney, has been 

 kind enough to assist me in obtaining the services of one of 

 his students, Mr. E. C. Andrews, to collect fossils from the 

 elevated reefs of Fiji. Mr. Andrews will spend a part of the 

 summer in Fiji collecting material and exploring in detail some 

 of the faces and slopes of the elevated reefs of the Archipel- 

 ago, and I hope to obtain ample material to determine the age 

 of these elevated limestones. 



In the earlier discusions of the thickness of recent coral 

 reefs by Darwin and Dana, no attention was paid to the possi- 

 bility of the substratum of recent reefs consisting of Tertiary 

 limestones. Elevated limestone containing corals of Tertiary 

 age were considered as of recent origin and as pointing to a 

 great thickness of modern reefs. It has been shown in Florida 

 that the modern reef is not more than about 50 feet thick, and 

 according to the borings from the artesian well at Key West 

 is succeeded by Tertiary limestones, in which corals occur at 

 intervals to a depth of 2000 feet. 



It has been stated by Dana and others that the borings from 

 the artesian wells at Honolulu to the rear of the shore line of 

 the fringing reef of Oahu indicate a great thickness of modern 

 reef corals. These statements are based upon the examination 

 of samples of finely ground particles of limestone accompanied 

 by an occasional fragment of coral, the age of which has not been 

 determined. The statements are further supported by the evi- 

 dence of Mr. J. A. McCandless, the engineer in charge of the 

 boring, who asserted to Mr. Dana and myself that in boring all 

 his wells the tool passed through a great thickness of corals, at 

 various levels. During my recent visit at Honolulu I was for- 

 tunate to be on the spot when Mr. McCandless was boring a 

 10" w T ell about 2500 feet from the shore line and perhaps 7 

 feet above high water mark. Down to a depth of 80 feet 

 nothing but recent reef coral rock was encountered, but from 

 that point to a depth of over 300 feet the limestone passed 

 through was of a very different character. It contained but 

 few corals, being composed almost entirely of the shells of 

 mollusks, mainly bivalves. The rock was white, chalky and 

 resembled in every way the rocks of the Vicksburg age of Florida 

 and of Yucatan ; but their age has not yet been accurately deter- 

 mined. Enough, however, is clear to show that the limestones 

 which form the substratum upon which rests the recent fring- 



