[CEYLON PEARL OYSTER FISHERIES 1903 SUPPLEMENTARY REPORTS, No. LI 



REPOIiT 



ON 



SEA-BOTTOMS AND CALCRETES 



COLLECTED BY 



Professor HEKDMAN, at CEYLON, m 1902. 



BY 

 J. LOMAS, A.R.C.S., F.G.S., 



LECTURER IN PHYSIOGRAPHY IN THE UNIVERSITY OF LIVERPOOL. 



[With ONE PLATE and TEXT FIGURES.] 



The samples of sea-bottom, about thirty in number, were dredged mainly from four 

 districts round the coasts of Ceylon : (l) About Point de Galle, (2) Trincomalee Bay, 

 (3) Palk Bay, and (4) the Gulf of Manaar and most of them were from the last 

 locality (see map, p. 161). 



In addition to the material brought up by the dredge, about twenty specimens of 

 rock were broken off from the bottom by divers, chiefly from the paars in the Gulf of 

 Manaar and along the west coast of Ceylon. 



The majority of the deposits were obtained from shallow water, 4 to 10 fathoms, 

 but a few from the Gulf of Manaar and off Galle are from a greater depth. 



Point de Galle and Neighbourhood. 



In Galle Bay, from depths of 6 to 8 fathoms, shells with sand were dredged. Large 

 drifted shells, such as Area, Anomia, Ostrea, Cucullcea, and Turritella, mostly in a 

 rotten condition, made up the bulk of the coarse material, along with large barnacle 

 valves and a few shark's teeth. The shells were worn, many brown in colour and 

 polished, indicating a partial conversion into a phosphatic condition. Encrustations 

 of Nullipores, Serpuloe, and Polyzoa covered the shells, and Clione borings were 

 common in those shells composed of calcite, while aragonite shells were often not 

 affected. 



r 2 



