142 Notes, prindpally Geological, on Southern India. [Jan.. 



soil arising from tlie detritus of the subjacent or protruding rocks. 

 About 2 miles west of Bellagoopah, are two long hills, running nearly 

 parallel to a broken range at a considerable distance to tbe west, with 

 a W. N. W. direction. These hills are tbe last that appear in view ; be- 

 yond them extends one broad expsinse of plain. They are of gneiss 

 with red felspar, and a hard dull mica : both white quartz and felspar 

 occur: the red however, gives the general colour to tbe rock. Thin 

 actynolitic veins are seen traversing it, though rarely. A basaltic dyke 

 passes through the northernmost of the hills in an easterly direction. 

 It has a dull green tint and imbeds iron pyrites. The hematif.ic and 

 granular iron ore are scarcely seen, and the natron deposit becomes 

 rarer. Common salt is got in abundance ; both this, chunam, and salt- 

 petre are manufactured at a village at a short distance hence. A loose 

 block of a dark dull siliceous green rock, with waving lines of a light 

 colour through its structure, occurs in the plain. 



Regarding the manuftjcture of saltpetre, the natives of the locality- 

 were a little delicate in furnishing me with informalion. At first they 

 said it was brought from the jungle, together with the earth from which 

 common salt is washed. Next, that it was not procured from the jun- 

 gle at all, but on the spot t and then that it was never to be found but 

 in and about villages. On enquiring the reason for this, they gave 

 evasive answers, but at last reluctantly confessed that it was got 

 from earth saturated with urine, and other animal matter; which, 

 with ashes and other refuse, are thrown together and allowed to re- 

 main till, I presume, the nitric acid produced by the decomposition of 

 the animal matter combines with the alkali of the wood-ashes, and 

 produces an impure nitrate of potash— the saltpetre of India. The 

 process is something different to that for obtaining muriate of soda. 

 The mass of earth is washed with water; which, after dissolving its sa- 

 line contents, is evaporated to a certain extent by boiling. The solution 

 of a dirty brown colour, is then poured into a cistern lined with chunam. 

 Small branches and bushes are put in, on which the salt crj'stallizes. 

 They are then taken out : the salt separated, either washed and re-crys- 

 tallized, or dried for packing. It is sent to the Bellary and Madras 

 bazars. 



The direction of the strata at Bellagoopah is N. N. W — dip of 25° to 

 the N. E. 



Honoor. — The sections of the soil in the rivulets near this show a 

 stratum ofregurfrom 2 to 5 feet in thickness, lying on gneiss, micace- 

 ous hornblende slate, or the pegmatiiic beds enclosing veins of a green- 

 ish eurite. In a bed of a rivulet I observed a basaltic greenstone dyke, 



