148 CEYLON PEARL OYSTER KEPORT. 



The finer material, obtained by sifting through a sieve with a mesh of 1 millim., 

 contained from 6T41 to 62 '52 per cent, of carbonate of lime, and included small 

 Molluscs, Echinoid spines, plates and anchors of Holothurids, spicules of Alcyonium 

 and Leptoclinum, as well as numerous Foraminifera, siich as Heterostegina, Glolri- 

 gerina, Textularia, and Spiroloculina, Nullipores and Crista. While the smaller 

 organisms have a fresh appearance, and are indicative of the life at present in the 

 district, the larger organisms are mostly dead, and evidently very old. 



The inorganic constituents were quartz grains, clear and well rounded, not very 

 plentiful, kyanite, corundum, zircon, rutile, tourmaline, and mica, A considerable 

 amount of coal, well rolled, in pieces ranging up to f inch in diameter, is no doubt 

 due to the proximity of a coaling station. 



At Welligain, to the east of Galle Bay, two samples were dredged. ( )ne, a fine 

 calcareous mud with shells, yielded 76*50 per cent, of carbonate of lime; and another, 

 obtained from a depth of 4 to 6 fathoms, contained many rotten shells, brown in 

 colour and bored by Clione, barnacle valves and Halimeda in a fresh condition ; a few 

 quartz fragments. lingular, ranged up to I- inch in diameter. The fine material in 

 both hauls consists of a smooth mud which cakes on drying, and contains a few small 

 quartz grains, tourmaline, zircon, spicules of sponges and Leptoclinum, Holothurian 

 plates, and diatoms, especially ( 'oscinodiscus. Foraminifera are not common. 



Teincomalee Bay. 



Off the mouth of Trincomalee Bay. at a depth of 12 fathoms. Foraminiferal sand 

 was dredged, containing (>7'7 percent, of one form, Heterostegina depressa. Mollusca, 

 including Area, Troclius and Patella, mostly rolled and encrusted, made up 4"8 per 

 cent., Corals and Polyzoa (Retepora and Cellepora) 0'2 per cent., Nullipores 8"0 per 

 cent.. Alveolina (two species) 0'9 per cent., and a few specimens of Echinocyamus. 

 The material which passed through the Hue sieve, L6;5 per cent,, consisted almost 

 entirely of small Foraminifera, including Pulvimdina, Textularia, Discorbina, 

 Miliolina, Cristellaria, Nonionina, Polytrema, and Nummulites. Pteropods and 

 Alcyonium, Holothurid and Sponge spicules were fairly abundant. 



The inorganic constituents include quartz grains, well rounded and ranging up to 

 3 millims. in diameter, and a black powder, much of which could be removed by a 

 magnet. The non-magnetic portion Mas fractionated by means of the double iodides 

 of mercury and barium, and showed a great number of small garnets, corundum, 

 tourmaline, and kyanite in the heavier fractions, while a little sub-angular quartz and 

 a few grains of mica made up the lighter portions. 



Palk Bay. 



North of Rameswaram, in Palk Bay, where shallow water (6 to 7 fathoms) conditions 

 extend over a great area, and where there is an almost complete absence of currents, 



