43G Geological Sketch of the Nelly her ties. [Aug. 



the slope of the hillock, has a W. and E. direction. It is overlaid 

 by a thick mass of basalt, which caps the whole hillock. In some 

 places, where this basalt lies immediately over the wacke, this last is 

 converted into jasper. Huge masses of basalt are strewed on 

 the top of the knoll, which forms a kind of table-land extending 

 eastward : some of these blocks in their upper surface assume an 

 amygdaloid structure, the cavities being filled with calcspar. 



I could not in that locality see whether the lower compact limestone 

 w r as or was not stratified. The more superficial and loose blocks, scat- 

 tered about on the soil, had no appearance of stratification. 



Judging from the appearance of the whole of those hillocks which 

 stretch from N. W. to S. E. in the neighbourhood, they seem to 

 have the same geological features as the one just descrihed. Indeed, 

 my friend Colonel Cullen, with whom I was examining this knoll, 

 told me, that in some of the neighbouring hills, the position of the 

 limestone and of the basalt is seen more clearly, on account of the 

 abruptness of some of their sides, and the deep ravines which 

 intersect them in every direction, so shewing the order of superposi- 

 tion in the four rocks ; which is the following : conglomerate red 

 sandstone supporting the wacke, overlaid by limestone, which is 

 covered by basalt*. 



The specimens marked X. and XI. are from the diamond mines at 

 Mallavelly, near Ellore ; they appear similar to the alluvial detritus in 

 other localities in India, where this gem is found. The kankar 

 accompanies the deposit in the same way as every where else. 



No. XX. is the gneiss of which the hillock near the village of 

 Carvera, close to Pundy, is found. In it the Cleavelandite replaces 

 the laminar felspar, and is seen not only disseminated through the 

 substance of the rock, but forming small strata by itself in long 

 acicular crystalsf . It is associated, in this rock, with a prodigious 

 number of amorphous garnets, of which some of the strata appear 

 entirely formed. 



The porphyry, No. XII., is from the hills which form the northern 

 boundary of the Garabunda pass, going from Kimidy, Garabunda, 

 Cassibogah, to Pundy. 



The hills to the south, and close to the pass itself, are sienitic 

 granite, (No. XXXIII. ;) while those beyond the porphyric hills to the 

 N., towards the high hill of Mehendry, seem to be formed of that 



* The trap near Sagur, described by Captain Franklin, appears to have the 

 same association of rocks as the one of which I send specimens. — Asiatic Re- 

 searches, vol. xviii. Geology of a portion of Bundelkhand, 8fc, page 30. 



f Is this the Pindyray of the TeliDgas, mentioned by Doctor Hevne in his 

 Tracts, page 283 ? 



