470 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [June21, 



4, On the Geology of the Neighbourhood of Nagpur, 

 Central India. By the Rev. Messrs. Stephen Hislop and 

 Robert Hunter. 



[Communicated by J. C. Moore, Esq., F.G.S.] 



[Abstract.] 



In the first place the authors describe the physical features of that 

 portion of the Nagpur district to which this Memoir particularly 

 refers, and give a full account of the geological observations already 

 made in that and the neighbouring territories. 



In pointing out the general geology of the district, they show that 

 the basis of the country is gneiss, quartz-rock, mica-schist, and granite, 

 on which reposes a sandstone very much interrupted, but stretching 

 far and wide. It is without fossils at Nagpur, but fossiliferous else- 

 where ; and, according to the authors, of the Jurassic age. 



Near Nagpur this sandstone is overlaid by a thick mass of trap 

 rock, an isolated patch of which forms the mass of the Sitiibaldi Hill. 

 This trap is compact below and vesicular towards the top, and is 

 surmounted by thin patches of a nodular trap. Between these two 

 trap-rocks is found a thin clay or cherty bed full of the remains of 

 freshwater shells and other fossils. In some places (as in the Takli 

 plains) the freshwater bed rests immediately on the sandstone, in 

 which case the vesicular trap is wanting, and the overlying trap is 

 sometimes present and sometimes absent. Sometimes a single thin 

 sheet of trap is present without any sedimentary deposit. 



The extent and relations of these several formations and of the 

 superficial deposits having been pointed out, the authors proceed to 

 describe their characters and contents, and to offer some observations 

 on their respective ages. 



The superficial formations are the black soil (Regur), sometimes 

 20 feet deep ; and the red soil, which is occasionally 50 feet thick, 

 and sometimes contains bones and freshwater shells. Each of these 

 rests on a brown clay, which has an underlying conglomerate, with 

 occasional mammalian remains. 



The next oldest formation appears to be the laterite or lateritic 

 grit, which seldom exceeds in thickness 10 feet in this district, and, 

 as usual, is unfossiliferous. Diamond mines have been opened in it 

 to the east of Nagpur. And in connexion with this subject, 

 Mr. Hislop remarks that the diamond matrix probably throughout 

 India is not sandstone in the several localities where the diamonds 

 are found, but an overlying breccia or conglomerate, frequently 

 resting on sandstone, but also occasionally on hmestone or gneiss. 



The next series of rocks is the trappean — with the enclosed sedi- 

 mentary deposit. 



The upper trap is from 15 to 20 feet thick, and of very great 

 extent. 



The freshwater deposit ranges from 1 inch to 6 feet in thickness, 

 and varies in colour and composition ; sometimes cherty, sometimes 

 argillaceous. Its fossils also are as variable in their distribution. 



