228 CARNEGIE INSTITUTION OF WASHINGTON. 



Dr. J. A. Cushman, of the U. S. Geological Survey, has furnished the 

 following lists of microzoa from samples 87 and 88: 



List of microzoa from bottom samples 87 and 88. 



No. 87. No. 88. 



A few coral fragments, occasional A few shell fragments, coral fragments, 



ostracod valves, and a few fora- ostracod valves, and some fora- 



minifera. minifera. 



Clavulina angularis. Orbiculina adunca. 



Orbiculina adunca. Peneroplis pertusus. 



Verneuilina affixa. Peneroplis var. discoideus. 



Polystomella striato-punctata. Verneuilina affixa. 



Quinqueloculina, etc. Polystomella striato-punctata. 



Quinqueloculina and Triloculina. 



The results of physical and chemical analyses and lists of foraminifera for 

 the bottom samples collected in 1912 are complete, but a difficult problem 

 remains. As the deposits are composed of calcium carbonate derived through 

 several different agencies, an estimate must be made of the percentage con- 

 tributed by each agent. In order to make the estimates, criteria for referring 

 the ingredients to their respective sources are necessary. This phase of the 

 investigation is considerably advanced and it is hoped satisfactory results will 

 be achieved. 



It has already been stated that the mud off the w^est side of Andros Island 

 is oolitic and only needs induration to be an oolitic limestone. There are 

 areas on Andros Island underlain by recently emerged oolitic marl or soft 

 limestone, thus permitting the stages of induration to be traced from that of 

 soft mud to that of hard, oolitic limestone. 



Bottom samples were collected in the eastern part of South Bight around 

 Golding Cay, and from Mastic Point to Bethel Entrance. The material is 

 distributed in a definite manner behind reefs and other obstructions, in 

 depressions, along the shore, etc. An account of these relations would require 

 more space than is permissible here. One important relation is indicated on 

 Dr. Mayer's map of Bethel Entrance. 



The bottom specimens obtained in 1914 have been divided and a portion 

 of each sent to Dr. Frank K. Cameron, of the U. S. Bureau of Soils, who 

 has reported the results of physical analyses. A representative set of samples 

 has been sent to Dr. Albert Mann, U. S. Bureau of Plant Industry, who dis- 

 covered that in areas of shoal-water calcareous deposits the diatoms are 

 likely to be deficient in silica, having imperfectly developed frustules. 



Dr. Karl F. Kellerman, in charge of soil bacteriology and plant nutrition, 

 U. S. Bureau of Plant Industry, has furnished the following preliminary report 

 as to the role bacteria may play in the precipitation of calcium carbonate in 

 the Bahamas and Florida: 



"The morphology of Bacterium calds has been determined, showing that the organism is 

 from 1m by I^m to 1m by 2m and bears a single polar flagellum. On the basis of the position 

 of this flagellum the species is changed to the genus Pseudomonas} 



"In the sample from Featherbed Bank, Biscayne Bay, Florida, both water and oolitic calcium 

 deposit showed the presence of large numbers of the organism designated by Drew Bacterium 

 calcis. No other organisms were sought for in this sample. 



"Bottom sample, station 206, 2 miles north of F. E. C. Railway Terminal, Key West, 

 Florida, shows large numbers of B. calcis. No other organisms were sought for. 



"The second sample from the same locaUty shows the presence of large numbers of B. coZcis 

 and also the presence of organisms which produce hydrogen sulphide. While the presence 

 of these organisms has been demonstrated, they have not yet been secured in pure cultures. 

 Organisms which produce a very slight acidity, probably due to carbonic acid, have devel- 

 oped in mixed culture. These have not yet been isolated in pure culture. 



'Bacterial precipitation of calcium carbonate. Jour. Wash. Acad. Sci., Aug. 1914, p. 402. 



