210 CRETACEOUS TIOCKS OF S. INDIA. [PaRT III. 



the North of Aiiai^audy exposes a bed of similar concretions in the lower 

 part of the Trichinopoly group; the matrix being, as in the former case, a 

 fine sandy clay. 



The best and purest kunkur I have noticed occurs in great abundance 

 in the laminated sandy clays of the Trichinopoly 



Kuukiir. 



group, to the West of Cullygoody ; and large quan- 

 tities may be collected in the nullahs and broken ground between that 

 place and Thapaye; a place to which the natives of the surrounding 

 villages are accustomed to resort for this material, Kunkur, j^erhaps 

 equally good, is found in similar beds of the Ootatoor group to the East of 

 Terany and Kauray, and the mineral occurs more or less throughout the 

 gypseous clays to the East of Ootatoor, and to the South and South-east 

 of the same place. On the Arrialoor beds in the East of the district, 

 it usually forms a bed of one or two feet in thickness, being probably 

 derived in a great measure from the denuded beds of the gi'oup; and a 

 similar bed frequently occurs in the same position on the surface of 

 the gneiss, where this rock is covered with regur. In the old alluvium 

 of the Vellaur and the other large rivers, kunkur alwaj's occurs to some 

 extent, but it is less abundant in the more recent deposits of the Cauvery 

 delta. It is probably in a great measure owing to the almost universal 

 distribution of this mineral, and the ease with which it is collected, as 

 much as to its excellence as a material for mortar, that the limestones 

 so abundant throughout the district have been hitherto almost entirely 

 neglected as a source of lime. 



On the sea shore, the broken shells thrown up by the waves, ai-e 

 collected to some extent for the manufacture of 

 lime ; and in large stations near the coast this 

 material is employed to a considerable extent in the manufacture of 

 the pure white marble-like stuccoes used for verandahs and interiors. 

 At Kundyamellur, near Porto Novo, a bed of sub-recent fossil-shells, 

 (chiefly a variety of Cytherca casianca,) is excavated for the same 



