2 THE INOKGANIC CONSTITUKNTS OF MARIKK IXVEi;TET?i;.\TKS. 



organic matter, and water. The carbon dioxide was calculated to satisfy the bases, and the 

 amount thus determined, subtracted from the total loss on ignition, gave a fair but rough esti- 

 mate of organic matter plus water. From the crude analyses thus obtained the reduced or 

 rational analyses, recalculated to 100 per cent, were computed. These rational analyses are 

 comparable, and give, closely enough, the essential composition of the material which goes 

 to build up the limestones, ilore refined work would add little toward the solution of our 

 main problem and would require much tedious labor. In the following pages the detailed 

 analyses are given, group by group, together with some of the older published data. After 

 the evidence has been presented a general discussion of its significance will be in order. 



In the former edition of this paper (pu])lished in 1917 as Professional Paper 102) the 

 analyses, with few exceptions, were made by the junior author. In this edition we are able to 

 present a large number of new analyses, made in order to strengthen weak series or to clear up 

 some outstanding uncertainties. These analyses, which were made by Messrs. A. A. Chambers, 

 R. M. Kamm, B. Salkover, and George Steiger, ai"e credited to the respective analysts. All 

 others were made by Wheeler. 



FOKAMINIFERA. 



The Foraminifera, because of their enormous abundance, are of great importance in the 

 formation of marine sediments. The globigerina ooze, for example, covers 49,520,000 square 

 miles of the ocean floor, at a depth of 1,996 fathoms, or 3,653 meters. The analyses of it pub- 

 lished in the report of the Challenger expedition on deep-sea deposits show that it consists 

 mainly of calcium carbonate, mth very little magnesia. Foraminifera are also abundant on 

 "coral reefs," and great masses of limestone are composed largely of their remains. 



These organisms, however, are so small, rarel}' larger than the head of a pin, that it is not 

 easy to obtain enough material of any one species for chemical analysis. The difficulty, fortu- 

 nately, is not insuperable, and with the help of others we Avere able to obtain representative 

 samples of seven species, as follows: 



1. Pulvinulina menardii D'Orbigny. Albatross station 2573; latitude, 40° 34' 18" N.; longitude, 66=' 00' W.; in 

 line from Long Island Sound to Cape Sable; depth of water, 3,188 meters; bottom temperature, 3° C. 



2. Sphiiwdirm dehUcens Parker and Jones. East coast of Mindanao, Philippine Islands; latitude, 8° 51' 45" N., 

 longitude, 126° 26' 52" B.; depth of water, 804 meters. 



3. Tinoporus baculalus Carpenter. Murray Islands, Torres Strait, Australia. 



4. Orbitolil.es murginatis Lamarck. South of Tortuga.s, Fla., at depth of 29.3 meters. 



5. Orbiculina aduncn Fichtel and Moll. Key West, Fla. 



6. Polytrema mineaccuin Linn6. Bahamas. 



7. Quinqueloculiiia auberiana D'Orbigny. Same locality as No. 4; analysis by A. A. Chambers. 



Rejecting organic matter and water ("ignition") and recalculating to 100 per cent, the 

 analyses assume the following rational form: 



