1841.] Feport on Productions and Manufactures. 387 



greenstone. I have nowhere seen mica take the place of the hornblende, 

 hence the whole formation might be more properly termed sienitic than 

 granite, particularly if the latter term is to be restricted to a determinate 

 compound. Sienitic granite, however, a compromise between the two, 

 would appear the better and most intelligible term for the rock as it 

 exists here. 



In a spur of hills running north south near the vilage, of Erapully ten 

 miles to the west of Hunumkoondah, I remarked that the granite becomes- 

 stratified or in other words passes into gneiss. 



At the foot of these hills the iron ore, afterwards to be described, is 

 found. 



I have not met with lime-stone yet, but from its being very commonly 

 employed by the natives, I should supp se that it existed in considerable 

 quantity. From their account it would appear to form nests in the granite y 

 the soil is of four descriptions, first the Chilka, a red gritty soil little 

 fitted, from the coarseness of its particles, for the purpose of agriculture. 



2nd. Lalzumeen, a soil also of a reddish hue, and evidently the former 

 in a more comminuted state ; this is put beyond doubt by the ant hills 

 formed on the Chilka soil being composed of this earth. 



We thus see that these insects, usually looked on as troublesome and 

 destructive pests, are not without their use in a grand natural operation. 

 The peculiar acid, the formic, which is their chief agent, acts on the 

 alkali and lime and most probably on the silica of the rockdebris, pul- 

 verizing it, and facilitating in all probability fresh combinations ; the soil 

 when manured is fitted for the reception of all kinds of crops without 

 reference to season. 



3rd. The Regur soil. As far as I have yet observed, this soil is of less 

 frequent occurrence than the two last mentioned ; as elsewere it is parti- 

 cularly adapted for cotton cultivation, and is generally esteemed the 

 richest of soils. It requires little or no manure : yet the ryots are in the 

 habit, previous to cropping, to let sheep loose upon it, it being supposed 

 that their urine is very advantageous to its fertility : this is exceedingly 

 probable as the salts which the urine contains, and the compounds they 

 form, must be very efficacious in loosening the soil, and preventing the 

 formation of clods, the common drawback of argillaceous soils. 



4th. The Talao-ka-jumeen. The black soil found in the bottom of 

 tanks. This is little esteemed, being a stiff clay, little permeable by mois- 

 ture ; it abounds in fresh water shells and at the beginning of the dry sea- 

 son, its surface is incrusted with carbonate of soda, of which mineral large 

 quantities are collected for soap making. A property, common to all 



