Geology of Southern India. 193 



ever having caused any alteration at the planes of junction. 

 In many places the sienite had completely decomposed the 

 hornblende into a dark red impalpable earth, and the felspar 

 into a similar white one, the quartz was in ferruginous pieces 

 undecomposed, with highly vitreous lustre and splintery frac- 

 ture. 



Passing from Mysore into the Barramahal district the 

 primary rocks still prevail. The features of the adjoining 

 country are now however altered, and the comparatively flat 

 and uninteresting plain is exchanged for mountain scenery 

 at once bold and beautiful. Lofty and precipitous hills 

 rising abruptly from the plain, sometimes clothed with rich 

 verdure and covered with trees and shrubs to their summits, 

 at other times presenting scarcely one solitary green spot 

 to relieve their desolate and rugged nakedness, bound the 

 view on every side, and the traveller following the road 

 which winds along their bases passes through a series of 

 valleys where kaleidescope-like, each turning brings new 

 beauties before him. On approaching, Kisuagherry, the 

 principal town in this district, the distant hills occasion- 

 ally exhibit the ribbed-like appearance characteristic of 

 columnar basalt. The town itself is overhung by one 

 of these, but an examination of it, effected with considerable 

 difficulty and risk, proved that the ribbed appearance was 

 due, not to the existence of columns but to linear deposits 

 of earthy and fungoid matter, the dark colour of which, 

 alternating with the natural colour of the rock, produced 

 when viewed from a distance exactly the effect of a co- 

 lumnar arrangement. These deposits were formed along 

 the lines by which little streamlets of water trickled down 

 from the summit of the hill, these having doubtless led 

 to the partial decomposition of the rock, and the formation 

 of soil sufficient for the fungi to vegetate in. Nests of 

 hornblende and greenstone were abundantly met with, and 

 the whole of the sienitic mass was traversed by veins of 

 pure quartz. The cause of the constant occurrence in 



