66 BULLETIN : MUSEUM OF COMPARATIVE ZOOLOGY. 



corals from near Tampa, on the west side of the peninsula. The 

 rounded grains, which are much fewer in number than the others, are 

 evidently transported particles and must have come from a distance, 

 since such quartz is not indigenous to any rocks in the vicinity of Key 

 West. 



The angular quartz sand was present in largest amount at the follow- 

 ing depths : 250 to 325 feet inclusive, 400 and 425 feet, 800 feet, and 

 1,250 feet. The least was seen at the surface, at 25 and 50 feet (none), 

 100 feet, 150 feet, 725 feet, 775 feet, 850 to 1,225 feet inclusive, 1,300 

 feet, 1,325 feet, 1,375 feet (none?), and below this there is only atrace in 

 each sample. 



With almost all the samples a flocculent precipitate settled out of the 

 HC1 solution after a time. This varied in color from a very light gray 

 through brown to a greenish black. The nature of this precipitate was 

 not determined. 



The surface oolite, though friable, was sufficiently compact to yield a 

 thin section. The nuclei of almost all the ovules are rounded or sub- 

 angular calcareous grains. One ovule was observed the nucleus of 

 which was a grain of quartz. The matrix of the oolite is very finely 

 divided soft rock, composed of entirely unrecognizable material as far as 

 any organic remains were concerned. The surface rock, in fact, and that 

 from 25 feet as well, seem to be entirely devoid of determinable organic 

 fragments. Small lumps of oolite or loose ovules were noted in about 

 half of the samples scattered along from top to bottom. The upper 

 half of the section is more oolitic than the lower, and the upper 500 

 feet more than any other portion. In appearance the ovules differ from 

 ordinary rounded grains of sand in being more regular in outline and in 

 having the exterior more highly polished. Many of these highly pol- 

 ished, regular ovoids were cracked open with a light blow of a hammer, 

 or by pressure on a glass plate, thus revealing the concentric shells 

 characteristic of true oolitic structure. To the present writer it seems 

 important to confine the term oolite to rocks composed of these con- 

 centrically built spherules embedded in a matrix, and not to extend it as 

 some writers are inclined to do to rocks made up merely of well rounded 

 fragments embedded in a more finely comminuted matrix. 



Organic remains which retain sufficient character for one to refer them 

 even to their class are not numerous except in a few of the samples, 

 and three of them (surface, 25 feet, and 550 feet) showed no determinable 

 fragments. Foraminifera arc abundant at 50 feet from the surface, and 

 sparingly present at 75, 325, 400, 575, G25, and G75 feet. At 725 feet 



