100 



Oeology of Bangalore^ and of 



with trees, and mnst not be confounded with the military road, less than 

 a quarter of a mile to the eastward of it, which also leads to the pettah. 

 He will here observe another dyke running about east and west. It is 

 seen first in the road, and protruding in rounded masses in the adjoin- 

 ing field ; its dark appearance well contrasted with the grey of the 

 granite through which it has burst — the soil resulting from the decom- 

 position of the two is also well contrasted. The greatest breadth of 

 this trap dyke is about 70 paces. On nearly a line witli it and going 

 westward, and across a large field, a confused group of granite rocks 

 is seen with a large one of irregular shape perched on the top' — one 

 portion of it having been taken away for purposes of building, I 

 mention this elevated portion as it forms a good guide in searching for 

 a dyke of basalt close to it, in the same mass of rock, and only a few 

 feet from it. By the mutual processes of quarrying and decomposi- 

 tion, only a very small portion of the dyke is here visible, and attached 

 to the granite, but on looking to the west end of this group of rocks, 

 distant about 30 yards, the continuation of the dyke is seen running 

 east and west — in breadth two feet at its east end — about 30 paces lu 

 length and at its western extremity about two feet three inches in 

 breadth. The granite rock it traverses has a smootli rounded outline, 

 is compact and dithcult to break, when broken into exhibiting numer- 

 ous pinkish dots, the felspar in some places of a light flesh colour and 

 some garnets distributed through it. I picked up a specimen of 

 magnetic iron ore close along side, lying in the field. This basaltic 

 dyke runs east and west and is on a line with, but distant about 27 

 miles from, the large and celebrated rock of Severndroog, seen rising 

 majestically from the numerous smaller hills around it. Sivagunga lies 

 more to the north-west> and is about the highest hill in Mysore. But 

 to return to the dyke— about 15 paces to the south of it a smaller one 

 is seen running in the same direction and through the same granite 

 block, it is 5 1 inches broad at its west end and three at the other, and 

 about 15 paces in length, and deserves more the name of a vein than a 

 dyke — in one place it has suffered displacement. On retracing our steps 

 back to the elevated mass occupying the Avest end of this group, a small 

 road is observed passing close to it, and leading to a very large gneiss 

 rock in the direction of the pettah— crossing this small path is another 

 dyke of basalt. It has undergone decomposition, and only a few pieces 

 protrude ; it is most likely connected with either of the two last des- 

 cribed, from which it is distant about 30 yards. Several hundred yards 

 further on in the same field, going west or a little to the north-west, 

 close to a small valley across which a b\ind has been th row n. there is a 



