200 



Notes 07t Geological Specimens from 



[JULT 



hood apparently in dykes, and in contact with the quartz which inter- 

 sects the. granite : but there being no section, and the water-worn 

 surface only being visible, no evidence could here be obtained, in 

 support of any of the opinions entertained by geologists, relative to 

 this singular formation, The amethysts are also found south of Jan- 

 ganapillv, and at Kamareddypettah, and Mr. W. Geddes met with 

 them, of a greenish yellow tinge, south of Balcondah. 



Granite Tract between Hyderabad and the Nirmul Hills. — The 

 valleys and some plains about Bekanurpettah are composed of 

 black soil, mixed with calcedonies, &:c. ; and to the west of the road 

 are some flat hills, which I had not an opportunity of examining. 

 They corresponded in their steep sides and flat summits with the trap 

 hills to be presently described, and Mr. Geddes informed me, that 

 they are formed of amygdaloidal trap, based on decaying granite. With 

 these interruptions, the granite continues to Kamareddypettah, but 

 the mamillary eminences, and the tors and loggings stones formed 

 from their decomposition, are of more rare occurrence. The granite, 

 however, still continues to exhibit the lamellar structure, and is easily 

 split into large slabs. In some instances, where the lamellae are thin, 

 the vertical fissures which frequently intersects them in right lines, and 

 greatly assist the progress of decomposition, cause the rock to break 

 into regular rhomboids. The last " tor stones" observed on the road 

 to Nagpur were north of Jakrampilly, where they occurred on a lofty 

 hill, on which there is a small pagoda. After leaving the basaltic hills 

 near Bekanurpettah and Jungampilly, black soil is seen in the valley be- 

 low a large tank, and some dykes of greenstone pass the road in the di- 

 rection of S. by E. to N. by W. at Kamareddypettah ; the granite is 

 lamellar white, with black mica and some hornblende, and fragments 

 of amethystine quartz are scattered about. A little to the north of the 

 town, on ascending a very gentle ascent, the red soil and granite give 

 way to black soil, derived from decomposed trap rock, which is concen- 

 tric on the top, but lower down is arranged in imperfect strata. On 

 descending the hill to the north, the black soils conceals the granite 

 for a short distance ; but at the bottom of the hill, and in the bed of a 

 small water-course, it is seen of the same appearance as before. 

 Immediately beyond this, there is a very remarkable hill, which is seen 

 from a considerable distance standing out from the gently indulating 

 country, and possessing the peculiar form of the trap hills of the Dec- 

 can ; it lies five miles north of Kamareddypettah, and four miles south 

 of the village of Nugger. On approaching it by a very gradual ascent, 

 the soil changes to black ; and all at once the hill rises with nearly 

 perpendicular sides, constituting a narrow ridge, about half a mile in 



