394 Notes, chiefly Geological, [No. 173. 



miles from Cuddapah, it crosses the valley of the Pennaur in a well de- 

 fined ridge, across which the road lies by a small pass, called the Bundi 

 Cunnama. The ridge to the south I found to be capped by sandstone. 

 The limestone here has an external scabrous aspect, owing to the less 

 rapid weathering of the veins of chert which run through it, and which 

 project in relief from its surface. At the eastern foot of the pass the 

 rock has been excavated for the sake of the dark flint-like chert it im- 

 beds, which was formerly used for gun-flints by the armies of the Cud- 

 dapah Nuwabs, and by those of Hyder and Tippoo ; but the material 

 is too brittle to make good flints. It is veined with quartz which often 

 forms a perfect network of cells, lined and stained with an orange- 

 coloured ochre. 



Cuddapah. — The limestone formation in the vicinity of Cuddapah and 

 the sandstone ranges to its south, have been described in notes from 

 Madras to Goa. The latter range I crossed to Govincherroo, in the 

 plain on the other side, by the Bankrapett pass. 



Govincherroo to Rachooty. — At Govincherroo granite is seen in low 

 bosses and large blocks, in sitti, at the base of the sandstone range ; and 

 is thus occasionally seen in tors and logging stones, and in the beds of 

 nullas, in the plain to Rachooty, about thirty- four and a half miles south 

 from Cuddapah. Near Rachooty, it often passes into pigmatite ; actyno- 

 lite and chlorite are seen in its veins. This granite formation evidently 

 extends to the eastward to the bases of the sandstone ranges of Chen- 

 dorghirry and Tripati, which are seen in picturesque outline, flanking 

 the plain and bounding the view to the right. 



The drainage lines of this part of the plain from Punganore, converge 

 in a N. by E. direction, to the singular gaps of Mandasir and Cheyair, 

 in the chain through which they find their way northerly to the bed of 

 the Pennaur near Sidhout, which we have lately left. It might be 

 worth while to examine the configuration of these gaps, and the sections 

 afforded by them. Dykes of basaltic greenstone are occasionally seen in 

 the granite. 



Rachooty to Chittoor. — The road lies over a flattish valley between 

 irregular clusters of granite rocks on either side, which occasionally 

 approach and recede, and sometimes disappear for a while, appearing again 

 at irregular intervals. Spurs of the rocks occasionally cross the valley or 



