350 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



particles, showing the characteristic conchoidal fracture, are 

 by no means uncommon. The presence of oxides of iron is 

 evident from the yellowish-red appearance of the deposit. 



Besides the quartz other minerals are represented to a 

 small extent. Grains of magnetite are sparsely spread through- 

 out the sample. Many of the grains of quartz have a distinctly 

 greenish tinge, and this is probably due to chlorite, formed by 

 the alteration of former furo-magnesian constituents of the 

 original rock, from which the deposit has been formed. A few 

 very minute chips of stone also are scattered throughout the 

 deposit. 



Organic matter is remarkable for its absence. After 

 carefully searching the sample all I found was a few pieces of 

 broken shells (Pecten and Tellina), one or two echinoid spines, 

 and one small piece of a coral. On one of the larger pieces of 

 shell an encrusting polyzoan was found. 



YII. [15.] 16/4/13 Near Bahama Ship. 



Turning to the second sample, a very different state of 

 affairs is found. It consists entirely of stones, broken shells, 

 and quartz sand, and, in general, resembles the deposits from 

 the " Hole." On examination, however, it is seen to differ in 

 many important respects. Firstly, the proportions of stones, 

 shells, and sand are different. In this deposit the most striking 

 fact is the preponderance of stones, and especially small stones, 

 over the other two main constituents. They vary from 

 4-2 grms. in weight downwards, but the great majority 

 are of uniform dimensions and small. They are well-rounded 

 and water- worn, and evidently are subjected to a considerable 

 amount of grinding as in not a single instance are growths 

 (such as polyzoa) found upon the surface, this being in striking 

 contrast with those got at the "Hole." This is probably 

 accounted for by the difference in depth, which at the " Hole " 

 was 22 fathoms and at the Bahama ship only 7 fathoms. 



