162 



PEOF. J. B. HAERTSOX OX EXTBAXEOUS [vol. lxXV, 



The results of the preliminary work are shown in the follow- 

 ing table : — 



Specimens. 



Extraneous Mineral Organic 

 matter. Residua. Residua. 

 Per cent. Per cent. Per cent. 



Nitrogen. 



Per cent. 



Mem nt Misery coral (1) 



•5993 "3870 -0123 

 •0912 -0809 '0103 

 •3338 .3232 -0106 

 •308 -214 . -094 

 •223 -184 -039 

 1 1 



•0008 

 •0002 

 •0009 

 •0057 

 •0024 



Other high-level corals (2) 



High-level beach-rock 



Lower-level corals (3) 



Lower-level beach-rock 



• 



(1) Eusmilia (much altered). 



(2) Diploria, Orbicella, and Eusmilia. 



(3) Agarieia, Astrcea, Colpophyllia, Dendrogyra, Dichocamia, Eusmilia, 



Madracis. Madrepora, M&ahdrina, Mussa, Mycotopliyllia, Orbicella, 

 Pectin ia. and Porites. 



Dr. F. W. Clarke, Chief Chemist, and Dr. W. C. Wheeler, of 

 the United States Geological Survey, published in 1917 Profes- 

 sional Paper No. 10J, giving the results of an exhaustive enquiry 

 into ' The Inorganic Constituents of Marine Invertebrates.' They 

 summarized on p. 12 the results of their work with massive corals 

 •as follows: — 



' These analyses are remarkably concordant, and show that the stony 

 ■corals contain little besides calcium carbonate. Silica and sesquioxides are 

 probably extraneous ; magnesia is altogether subordinate, although fairly 

 regular in its amount ; phosphates occur only in traces.' 



From the tables of ' Reduced Analyses,' given by the authors on 

 pp. 13 & 11, the proportions of silica and sesquioxides found by 

 them were : — 



SiO., 



A1 2 3 and Fe 2 O a 



Maximum. 

 •74 



Minimum. Mean. 

 •00 -132 



•00 -134 



The authors deal on p. 1 with the minor inorganic constituents 

 of marine invertebrates in the following words : — 



' In a strict sense completeness cannot be claimed, even for our analyses. 

 Minor constituents which have been detected in shells, corals, and sea- weeds, 

 such as lead, copper, and manganese, have been ignored. They occur only in 

 traces, and have little or no significance with respect to the larger problem 

 before us.' 



The proportions of extraneous mineral matters found by me in 

 the fossil corals, other than the calcitic corals from Mount Misery, 

 are very similar to the amounts of total silica and sesquioxides 

 found hj Dr. Clarke & Dr. Wheeler. The proportions found in 

 the Barbados upper- and lower-level beach-rock, '323 and '181 

 per cent, respectively, also fall within the limits which their 

 investigations indicate should characterize a limestone of similarly 

 complex origin. 



