22 



Geology of the Country 



[July 



abounding with mica, of which alone some of the strata are exclusively 

 formed. The outgoings of some are seen below the tank near the 

 Bungalow, where the usual contortions in the strata of this rock are 

 strongly marked (No. 71). 



Adamancotta. — All the plain, in the vicinity of the Bungalow, and as 

 far as the Cavery, has numerous quartz pebbles, some angular, and 

 others rounded, which proceed, as every where else in the south of 

 India, from the decomposition of hornblende slate (which is the sur- 

 face rock at this place), and consequent disintegration of the quartz 

 veins invariably intersecting it (No. 72). 



The stratification in the rock here is well and clearly developed, 

 the minerals composing it occasionally alternating in separate strata; 

 so forming what might be called sienitic gneiss. 



It is not an unfrequent occurrence in this schistous diorite to find 

 some of the strata composed of two minerals only, to the entire exclu- 

 sion of the hornblende ; the felspar and quartz being regular crystals. 

 In this case the rock assumes a pegmatitic composition, and, like that 

 rock, decomposes into kaoline (No. 73). 



Loose pieces of quartzy magnetic iron ore are frequently met with 

 in the plain, but I was not fortunate enough to find any corundum, 

 which, I have been informed, exists in this neighbourhood. 



Salem. — The whole tract of country, between Adamancotta and Salem, 

 is hilly, and full of inequalities, on account of the many branches and 

 spurs, proceeding from the Shevaroy-hills, which intersect it in all 

 directions. 



The composition of the rock forming these hills is the same as that 

 of those they are the prolongation of, that is, hornblende slate. I do 

 not recollect to have seen the stratification of this rock any where in 

 India (Mookoorty Peak excepted) better marked than in the hills 

 through which the new Pass has been constructed, where the sections 

 for the road shew it clearly, and also in the beds of small rivers near 

 it (No. 74). 



As in many other places in India, this schistous diorite near Salem, 

 contains thick veins of quartz, which, protruding above the soil, form 

 small knolls and ridges, which may be taken for a quartz rock forma- 

 tion; the general dip of the strata of this slate is west. 



As we were to pass Salem by night, and the magnesite formation 

 being situated only five miles before reaching that place, I should 

 have been sadly disappointed, had I to proceed with the whole party, 

 and to pass through it without seeing this interesting spot ; so I had it 

 arranged that, as soon as my Palanquin arrived at the place where the 

 chunam is found (they call the magnesite so, thinking it lime), the 



