150 



GEOLOGY OF TRICHINOPOLY, &C. 



[ClIAP. VIII. 



Sandstone. 



trafRc. In addition to their exceeding haidness and difficulty of work- 

 ing", there is a great objection to their employment as building-stones, 

 namely, that in damp climates the basaltic varieties absorl) and retain 

 great quantities of moisture. 



Sandstone quarries came under our notice in one place only, namely, 

 to the north of Verdachellum, in the Cuddalore 

 series of rocks. The generally very friable sand- 

 stone is there compact enough to be converted into cattle-troughs, rice- 

 mortars. 



Laterite, if well selected, offers a fair building- stone, and, though apt 

 to wear away soon under heavy traffic, makes a 

 good road material, because of its strong binding 

 qualities. It is quarried in various places for both purposes, especially 

 near Tanjore ; for example, along the road from Trichinopoly to Tanjore, 

 and in many of the villages of the detached areas shown in the map. 



It is quarried at or a little below the surface, square blocks being 

 picked out with a crow-bar, or the ordinary pick used by the natives,"^ 

 and then left for some time to become hardened. While being 



Laterite. 



* At Cottayum (Kotium), in Travancore, an axe of very peculiar structui-e is employed 

 to cut and dress the slabs of laterite. The head of this kind of axe, instead of having the 

 helve inserted in it, is itself fastened to the helve by means of two rings and a wooden 

 wedge (as shown in the sketch annexed. Fig. 6). 



Fig. 6. — Axe used fok cutting laterite in Travancoke. 



The axe itself is a double wedge about 10 inches long, by 3J in width, and ^ths of an 

 nch in thickness at the thickest part, which is nearest to the cutting edge of the instrument. 



(372) 



