SKEATS: CHEMICAL COMPOSITION OF LIMESTONES. 61 
Pollard contributed some analyses of limestones from Namuka, Fulanga, 
and Kambara. These limestones all contained a fair proportion. of 
magnesium carbonate. 
Namuka. 
White Rock Red Rock 
Calecium'earbonate « < .. . « 18:6 Calcium carbonate .... . 852 
Magnesium carbonate . . . . 21.5 Magnesium carbonate . . . . 6.7 
Ferric oxide and alumina. . . 4.2 
Sili@are. ache aes, F< tue OTD 
100.1 99.6 
The limestones from Kambara and Fulanga yielded respectively 19.8 
and 10.7 per cent of carbonate of magnesium. 
References to the earlier expeditions of Mr. Alexander Agassiz among 
coral reefs are now given in chronological order : — 
1878 West Indies. Bull. Mus. Comp. Zodl., Vol. V., No. 1. 
1883 The Tortugas and Florida Reefs. Mem. Am. Acad., Vol. XI, 
p» LO¢: 
1888 West Indies. Three Cruises of the “ Blake,” Vol. L., p. 66. 
1889 Hawaiian Islands. Bull. Mus. Comp. Zo6l., Vol. XVIL, p. 121. 
1892 The Galapagos Group. Jbzd., Vol. XXIII., No. 1. 
1894 Bahamas and Cuba. Jbid., Vol. XXVI., No. 1. 
1895 Bermudas. Jbid., Vol. XXVI., No. 2. 
1896 Florida. Jbid., Vol. XXVIII., No. 2. 
1898 Great Barrier Reef of Australia. Jbd., Vol. XXVIII., No. 4. 
1898 Fiji. American Journal of Science, February, 1898, p. 113. 
His later expeditions, together with those of Prof. T. W. Edgeworth 
David, Dr. C. W. Andrews, and Mr. E. C. Andrews have been referred to ; 
but as their collections form the subject-matter for this paper, their 
published reports will be more particularly noticed in dealing with the 
microscopical and chemical results obtained from an examination of the 
collections from the several islands. Mr. R. L. Sherlock has recently 
examined many of the thin sections, whose microscopical characters are 
described in this paper, and has identified and named the fossils they 
contain.? 
CuemicaL Metuops. — Before deciding on the quantitative methods to 
be employed in the chemical examination of the collections, a consider- 
able number of qualitative analyses were made with a view to determin- 
1 Bull. Mus. Comp. Zool., 1903, Vol. XXX VIII. 
