Chap. L] 



ECONOMIC GEOLOGY. 



207 



Guddalum, iu the latter from the Red Hills, over which the road passes for 

 some miles. 



Limes and Cement materials. Of the various materials available for 



Materials used by im- ^^^^ manufacture of lime, two only are used, viz., 

 *'^'^*' kunkur and shells. The former occurs abundantly- 



over a great part of the area described, both on the crystalline and 

 sedimentary rocks, and to some extent in the fluviatile alluvium of 

 Tanjore and South Arcot. The latter is used on the Coast, and at those 

 spots at which shells are found in suflficient abundance in a fossil state ; 

 chiefly at Kundyamalur, a few miles to the West of Porto Novo. 



The intermittent process of burning is the only one practised, and the 



^^ . „ ,. quantity of lime burnt at one operation is usually 



Native process oi lime ^ j i j 



burning. small, frequently less than a hundred weight. The 



kilns are of mud, and vary in construction : in South Arcot they are 

 Fig. 22, Native Lime-kilns in South Akcot. 



-io:ft- 



^ 



J^JfeE*--*—- fi- Jf^'^^ *^ Tvo'strfBijaR. ^ 



usually trough shaped, and furnished with bars either of^thick sticks, or 

 bricks and potsherds built into the walls, at about 18 inches from the 

 ground {see Fig. 22). On these the kunkur, (in fragments of the size of 

 a walnut or less,) or shells are piled, mixed with the fuel, which consists 

 of wood, charcoal, or where the Palmyra is abundant, of the dead leaves 

 of that palm ; and the mass being ignited from below, is allowed to burn 

 out, fresh fuel and material being piled on the top, as the charge sinks, 

 until the kiln is full of quick lime. This is allowed to cool and is then 



