Chap. VIII.] economic geology. 151 



quarried, the stone is sectile, requiring but little trouble in the dressing-, 

 but eventually it becomes quite hard. Near Cuddalore and Pondicherry 

 it is largely employed as a road metal. 



In Makbar, Cochin, and Travancore, and other parts of the 

 Western Coast, laterite is used most extensively as a building material, 

 and seems to take the place of bricks in every possible way. 



It is, from its very vesicular character, but rarely susceptible of any 

 thing like ornamental carvings. 



On the subject of the value of laterite as a building-stone, a consider- 

 able diversity of opinion exists amongst those well 

 Value of Laterite. 



able to form a correct judgment on such a matter ; 



by some its value is greatly extolled, by others it is rejected as a very 

 untrustworthy material, on account of its very varying degree of resist- 

 ance to crushing power. 



The fact is, laterite frequently varies greatly in quality, even in 

 different parts of the same bed ; hence, in a work in which dm-ability is an 

 object, much circumspection should be used in the selection of the laterite- 

 blocks to be employed, which should be neither very sandy, nor yet want- 

 ing in iron. 



Where" of poor quality, the laterite soon crumbles away when exposed 

 to the influence of weather and moisture, as may be seen in the basement 

 of many of the houses in the Fort of Tanjore. The laterite has there 

 weathered away, leaving the walls perfectly honey-combed, and the layers 

 of mortar, which are more durable, standing out as a regular net-work.* 



This, though useful in cutting up the soft clayey laterite, is of little strength when 

 tried against timber. The helve is generally made of Areca or Sago-palm wood. 



* The laterite in this case was in aU probability badly selected, and of too sandy a 

 variety, for in all my subsequent observations of this stone as a building material, it would 

 appear that continued exposure to atmospheric influences, or wet, as in the case of tanks 

 or bowries, only tends to improve the stone. Most of the religious edifices and tanks con- 

 structed of this stone show the lines and angles of the carvings as sharply as though fresh 

 from the builder's hands. Laterite is however very absorbent of moisture, and houses built 

 of it ought to be internally lined with cement, or good chunam, a process which is not at 

 all necessary in the use of massive syeuitoid gneiss for the same purposes. — E. B. r. 



( 373 ) 



