1839] 



some other portwm of Mysore. 



lOi 



large gneiss rock much quarried, upon which a rude mud hut has been 

 erected. Near this hat another basaltic dyke or vein is seen running 

 about E. N. E. and W S. W. the strata of the gneiss about N. W. and 

 S. E. ; it is 57 paces in length, it seems to have entered from the west, 

 ward, where its breadth is 8| inches, takes rather a zigzag course, and 

 at last becomes small and thread like, and is lost in the gneiss. 

 In two places the basalt of the dyke has decomposed on its sur- 

 face into a brick coloured looking substance. 



Crossing the bund, and entering a spot where there is a good deal of 

 cultivation and many trees, we arrive at a tank not of very great size, and 

 not to be confounded Avith a very fine one near and close to the 

 north-west gate of the pettah. As there is a peculiar arrangement 

 of rocks close to the bund of this tank I will first describe them, 

 before proceeding to the further account of the trap dykes. A large 

 black mass, close to the end of the bund, is seen running down with a 

 considerable slope, and is lost in the tank. x\t a distance it looks like a 

 basaltic dj^ke, which I at first took it for, but it runs with the strata, 

 does not cut across them, and is not basalt but hornblende slate. It is a 

 large mass of hornblende slate, perfectly dyke-like in its appearance. 

 The gneiss near it has a very slaty appearance, and contains very little 

 mica, and next to it there are large masses of a very slaty rock of a grey 

 colour, the strata perpendicular to the horizon — it appears to be a sort of 

 argillaceous chlorite slate. Between this chlorite slate and the dyke-like 

 hornblende slate, the gneiss rock, as just described, has undergone altera- 

 tion, and assumed a slaty aspect. The observer now finds himself on a 

 road which leads into the pettah ; and about a hundred yards from the 

 spot now described, there is a small tope of trees and apparently the 

 continuation of the trap dyke which was seen about half a mile off 

 bursting through granite — this dyke crosses the road, and is seen for 

 miles stretching in a westerly direction, forming litile elevations. If 

 instead now of following the road which leads close ro a very magnifi- 

 cent tank, and enters the pettah at its north-west angle, we turn olf to 

 the right and take the road round the pettah wall, some way on we 

 find a road leading out of the pettah and taking a course about due 

 west— this is the road to Severndroog formerly alluded to. There are 

 some rocks to the south-west of this road, where the geological observer 

 will find another basaltic dyke running about east and west— he also 

 now finds himself in the very region of rocks, in the midst of which 

 there is a very large village and several sawmy houses cut out in the 

 rocks. In a direction further on again, he comes into the high road 

 leading to Kingaree and hJeringapatam, which I will now pursue, but 



