184 7. J Notes, chiefly Geological, from Gooty to Hydrabad. 481 



of notice by those geologists who consider the regur or black soil of 

 India as a fluviatile deposit ; or as the washings of trap rocks. 



The still unflooded parts of the river bed consisted of collections of 

 light-coloured sand and silt, and accumulations of pebbles from the size 

 of a No. 4 pellet to that of an egg, as before stated. These pebbles 

 were chiefly of quartz, calcedony, cornelian, agate, and Mocha stones : 

 fragments of onyx and sardonyx rare and small. Also common and 

 semi-opal ; heliotrope, and jaspers of various shades of red, brown, 

 green and yellow. 



I picked up some rolled bits of radiated zeolite, limestone, pegmati- 

 tic granite with reddish felspar, and find nodules of cream-coloured 

 and greyish white kunker. 



Nothing but the very toughest fragment of the overlying trap, 

 whence these calcedonies and zeolites have been washed for a distance of 

 not less than 100 miles to the N. W. have remained entire ; these 

 debris we must look for nearer to their situs, or try to recognize it in 

 the sands : thus following the maxim in geological dynamics ; viz., that 

 in alluvial beds the most indurated portions of transported matter 

 will always be found at the greatest distance from their situs. 



I am informed that in the bed of the river nearer its embouchure, 

 the cat's eye and diamond are found in the Polnad Circar, and I know 

 that the last named gem is found in the bed of the Kistnah in the 

 eastern parts of Kurnool near Siddeswar, and still further east beyond 

 the wilds of Perwut and the diamond mines of Purtial, Moogaloor, 

 Codavacutloo, and Oostapully, which are on the N. bank of the Kistnah ; 

 the diamond I have no doubt, has been washed out of the diamond 

 sandstone formation of these tracts east of Paugtoor and Kurnool ; but 

 the cat's eye, like those in Ceylon, is probably from the gneiss or grani- 

 tic rocks. 



From the Kistnah to Judcherla, 60 miles northerly. — The lime- 

 stone formation extends about three miles in the plain north of the 

 Kistnah, when granitic rocks are met with associated with gneiss in 

 the vicinity of Myapore. This granite rock spring up irregularly 

 from the surface of the plain, leaving often level spaces between each 

 hill, but those of gneiss usually form short, and more regularly conti- 

 nued ridges. 



These elevations, however irregular in detail, have a general direction 



3 R 



