6ii FOOTE : GEOLOGY OF MADURA AND TINNEVELLY DISTRICTS. 



hundred yards. The depth of the section is also very trifling, and 

 nowhere exceeds 4 or 5 feet vertically. The calcareous sandy clay, which 

 is of yellowish or brownish ochrey character, is richly charged with large 

 and small oysters ; Areas, closely allied to, if not identical with, A. granosa 

 and Cythereas, possibly referable to C. castanea. The oyster bed may be 

 traced for fully a mile to the north-west as a thin fringe lying in spreads 

 and patches on the surface the gritty sandstone which itself rests on the 

 gneiss. 



About \\ mile east-by-south of the junction of the Yellava Odai 

 Puliman Kulam out- ^^^ ^^® Nambi-Ar, and about the same distance 

 <=">?• south-south-west from Puliman- Kulam pariah vil- 



lage, is a tiny outcrop of grey limestone showing in the middle of the 

 teri. I did not observe any fossils in the limestone, but close by I picked 

 up two large subfossil oysters of the same species as that occurring in the 

 Yellava Odai oyster bed. 



The next occurrence of the marine beds following them in a 



north-easterly direction is at Tissianvilai (Teg- 

 Tissianvilai section. 



gayamvella) in a well-section in a garden on the 



west side of the high road as you enter the village from the south. 

 The well is revetted, but at the time of my visit a small heap of the 

 excavated rock lay close by and showed a purple-brown, coarse, but 

 rather friable, grit with many marine shells. The only entire ones 

 which I was able to extract were valves of the little Venus scabra, of a 

 small Area and a specimen of Bentalium octogonum, all of them shells 

 very common at the present day in the Gulf of Manaar. 



To the north of Tissianvilai, as the ground begins to rise on approach- 

 Bishop Caldwell's i^g" the south end of the great Sathan Kulam teri, 

 ^^^^'^^* is a patch of hard calcareous rock, varying from 

 a nearly pure shelly limestone to a very coarse grit, cemented by a 

 calcareous cement and almost quite devoid of fossils. The limestone 

 would be almost entirely hidden by the teri sand, but for numerous 

 pits which have been dug to allow of the quarrying of the rock 

 which is carried on on a rather large scale, there being a considerable 

 ( 62 ) 



