360 Capt. Cullen's Notice of the Geological Features 



The granites of this division were generally of a light colour, 

 shades of white and of a coarse texture ; the darker varieties, 

 however, inclining to brown or red, being, I think, the finer 

 grained. 



The quartz and felspar were by far the most abundant consti- 

 tuents, and gave the colour to the rock ; the hornblende* which 

 was of a dark green, being very irregularly and sparingly dis- 

 tributed. There seemed to be little or no mica. 



The texture of the trap was very uniform, and of a fine 

 grain, composed distinctly of hornblende, and greenish white 

 felspar. 



The porphyritic variety, alluded to near Curcumbaddy, 

 contained irregular crystals of felspar, of from one-tenth to 

 five-tenths of an inch in diameter, of the same colour as the 

 felspar of the basis. 



The transition of clay-slate is very sudden and complete. 

 The low hills immediately at the back of Curcumbaddy con- 

 sist of a compact quartzose sandstone, or hornstone, but the 

 clay-slate may be observed in contact with it, within 100 

 yards of the north side of the village. From this spot clay- 

 slate forms the grand and almost sole constituent; for, with 

 the exception of occasional beds of calcareous schistus and 

 flinty slate in the valleys and sandstone-caps on some of the 

 hills, the great mass of the two singular mountain-chains 

 which form the boundary of this interesting valley, on a line 

 of upwards of 150 miles, appears to consist entirely of that 

 rock. I must add, however, that should an actuarpersonal 

 examination of the strata be considered indispensable in sub- 

 jects of this nature, these observations must of course, in such 

 a case, be considered as only strictly applicable to the high 

 road itself, or to a short distance on either hand. 



The seams of stratification are, however, so entirely regular 

 and distinct on the slope of the hills on either side, and in 

 general so decidedly characteristic of these clay- slate tracts, 

 that it is hardly possible to be mistaken in their nature, even 

 at a distance of several miles. Towards the commencement, 

 the hills are rather thickly clothed with wood ; but on ap- 

 proaching Cuddapah, and all to the north of that place, the 

 trees are stunted, and but thinly scattered over their sides, 

 leaving the strata-seams, like so many artificial terraces or 

 ploughed furrows, distinctly exposed to view. The internal 

 structure and colour of the slate, in a tract of such extent, 

 were of course very various. At Curcumbaddy, and for a 

 stage or two afterwards, chiefly shades of red ; about Wunti- 

 mettah, purple and gray. Shades of these two last prevailed, 

 I think, generally, till within eight miles south of Poonnamilla, 



when 



