148 GEOLOGY OF TRICHINOPOLY, &C. [ClIAP. VIII. 



west of Coimbatoor, have been used by the Engineers of the Madras and 

 Beypoor Railway for walls and other purposes^ and appear to have 

 given complete satisfaction. If well selected^ they are not only admi- 

 rably adapted for general building purposes^ but could advantageously 

 be applied to decorative purposes, being susceptible of a high polish. 

 The marble must, however, not be polished in the native method, which 

 greatly defaces the stone by choking all the minute cracks between the 

 crystals with a dirty black substance ,• at least such was the case with 

 specimens which we had cut and polished in Trichinopoly. 



The beds at each of the localities enumerated in Chapter IV would, 

 we feel quite confident, yield marbles in every way equal to those of 

 Muddakurray and Suokegherry Droog, and are well worth quarrying, 

 both for building stones and for hme-burning. In the former capacity, 

 their superiority to bricks is unquestionable, and they are so much more 

 easily and cheaply dressed than any of the siliceous gneissic rocks, that 

 they merit every attention. The beds are, as a rule, singularly free from 

 joints, and blocks of immense size might in many places be obtained 

 with very little difl&culty. 



As already mentioned in Chapter IV, we no where found the natives 

 using the limestones, even for the pm'pose of lime-burning, for which 

 object they prefer coUeeting the common kunkur, so generally distributed 

 over the country. The lime is burnt in little mud-built kilns of elliptical 

 or circular shape, the same, in every respect, as those described by 

 Mr. Blanford at page 208 of his Report. 



One of the minor branches of mineral industry, that of cutting 

 and polishing the varieties of quartz found in the grits of Vellum, has 

 already been alluded to at page 36. The principal varieties of the so- 

 called Vellum stones are the pellucid or rock crystal. 



Lapidaries at Vellum. ,, , , t ■, ^ -i n 



the dark brown or smoky quartz, the yellow or 



cairngorm, and amethyst ; these are cut by the lapidaries at Tanjore and 

 Trichinopoly into a variety of ornamental and useful articles. The orna- 

 mental articles are chiefly brooch-stones cut in the brilliant, rose, and 

 ( 370 ) 



