62 



Crystalline Limestone [no. 5, new series,, 



N. E. direction. These hills consist of thin alternating bands of 

 crystalline, limestone and gneiss, the banded structure of which 

 is absolutely coincident with the foliation. Here and there small 

 contortions occur in the rock, which are rendered very strikingly 

 visible by the erosion of the intercalated band of the limestone 

 from atmospheric causes, and it is this unequal erosion which has 

 given to the hills themselves the jagged appearance already allud- 

 ed to. 



The range of hills ceases suddenly about half a mile to the east 

 of the road where the rock becomes much contorted, and an ex- 

 posed surface of pure crystalline limestone, unmixed with Gneiss 

 extends for the space of about 200 yards, between the hills and the 

 cultivated land beyond. The limestone is largely crystalline, being 

 composed of an agglomeration of small rhombohedrons of Carbo- 

 nate of Lime, the characteristic cleavage of which is frequently 

 very distinct. In color, it is usually of a pale mottled grey, fre- 

 quently passing into pink, and occasionally becoming nearly white. 

 It is intersected by a few minute veins of Granite, which have ap- 

 parently been intruded while the limestone was in a molten condi- 

 tion, so that by slight movements in the fluid mass, they have 

 been drawn out and twisted into peculiar thread like forms, re- 

 sembling those frequently seen in the intermixture of two colors on 

 the marbling trough of a bookbinder. In general, the rock is very 

 aompact and blocks or slabs, of almost any required size, might be 

 quarried without much difficulty. 



From this spot, which is the most easterly point at which the 

 limestone is at present known to occur, it passes westwards form- 

 ing a band of 30 or 40 yards in width in the substance of the 

 schists, into which it graduates along its northern edge, forming 

 the banded rock already described, while its vertical extent is pro- 

 bably very great. It has been traced for a distance of about 7 

 miles along the foot of the range of hills already mentioned, which 

 to the West of the Palghat road, become very elevated and form a 

 ridge of about 2,000 feet in height above the general surface of the 

 surrounding country. At a point about 2 miles west of the village 

 of Ittrumudday, the line of Railway from Madras to Beypoor, cuts 



