508 A. K. Coomdraswdmi/ — Recent Marine Clays of Ceylon. 



VII. — Eecbnt Marine Clays at Kdchavelli, Ceylon. 



By Anaxda K. Coomaraswamy, B.Sc, F.L.S., F.G.S., Director of the 

 Mineralogical Survey of Ceylon. 



KUCHAVELLI is twenty-two miles north of Triucoiualee on the 

 east coast of Ceylon. Two miles south of Kuchavelli is the 

 mouth of the Salape aru. On the right bank of this river, near the 

 mouth, raised beach, consisting of shelly sandstone, is exposed. 

 The sandstone is often full of marine shells, and there are also thick 

 growths of oysters attached to upstanding masses of rock. The 

 bed is from 6 inches to 2 feet in thickness, and is exposed about 

 1 foot above high-water mark, and stretches down the sloping bank 

 between tide-marks. This is the ordinary raised beach of Ceylon, 

 a deposit usually occurring at or below high-water mark, and now 

 being continually eroded at numerous points on the coast of Ceylon 

 where it is exposed (e.g. Beutota). This deposit will not now be 

 further spoken of. 



The Salape aru is really the name of the estuary of several rivers ; 

 proceeding up the river inland, the Matti aru is reached, a shallow 

 river with alluvial banks eight or ten feet above the water on either 

 side. Extensive sandbanks are found on one side or the other of 

 the river, alternating on the meanders with places where erosion is 

 in progress. These banks are covered with marine shells, the large 

 flat Piacunas being most common. There are also found clayey 

 nodules including marine shells, crabs, and it is said sometimes 

 tortoises and fishes. The crabs are collected for use as medicine, 

 being powdered and mixed with milk or water as a specific for 

 diabetes. The crabs fetch from 25 cents to a rupee each, according 

 to size. 



The shell-covered sandbanks continue for some distance. The 

 crab bed and source of the marine shells was detected in situ about 

 a mile and a half from the mouth of the river and not far from a hill 

 called Nachchiyar Malai. The bed is exposed in the river bank, 

 and the section is roughly — 



ft. ins. 



1 . Soil and alluvium , 9 



2. Crab bed — clay full of marine shells, nodules, etc. ; 



iu parts sandy ... ... ... ... ... 26 



3. ? More sandy beds underlying the clay. 



Neai'ly all the shells common on the sandbanks, as well as a crab 

 nodule, were found in situ. The top of the fossiliferous clay is 

 probably about one foot or less above sea-level, and the fossils occur 

 chiefly in the lower part and have to be dug out from below water- 

 level. Beside the shells, etc., small pieces of wood are common in 

 the clay, and crystals of selenite also occur. It is simply crowded 

 with the flat Piacunas (?). 



In the Colombo Museum are a number of fossils from Palantiar, 

 the exact situation of which I am uncertain. The crabs are also 

 said to be found at Mullaitivu, on the coast north of Kuchavelli. 



