1840.] 



of the Great Basaltic District of India, 



custrine fossils, probably referable to the tertiary epoch, from a portion 

 of this district extending 140 miles north and south, and having pro- 

 cured others from localities to the north and west of that which furnish- 

 ed my own collection, I am induced to submit the specimens to the 

 Society*. If they should be deemed of sufficient value, I wish a selec- 

 tion to be deposited in the museum, to afford a means of comparison 

 with a duplicate set, which I shall forward to the Asiatic Society of 

 Bengal.| 



But it is not alone by supplying some data from which to infer the 

 relative age of the great trap formation, that these specimens are valua- 

 ble. They will afford the means of connecting the great sandstone 

 formations of the south and north of India, containing the celebrated 

 diamond mines of Par teal (Golcondah), Bangnapilly, and Panna, as well 

 as the limestones and schists associated with them ; and which, from the 

 latitude of Madras to the banks of the Ganges, exhibit the same charac- 

 ters, and are broken up or elevated by granite or trap rocks, in no respect 

 differing in mineralogical characters or geological relations, A few 

 remarks on these formations, and the physical geography of the countries 

 in which they occur, will be a necessary introduction to a more particular 

 account of that portion of the trap district in which the fossils were 

 found, Mr. Calder's sketch not being sufficiently detailed, and the map 

 attached to his memoir containing some errors of material iraportance.:|: 



GENERAL SKBTCH OF THE PHYSICAL FEATURES, HYDROGRAPHY, &C. 



An elevated tract to the north-west of Bundlecund (not included 

 within the range of the Map,) may be considered as the geolo- 

 gical connexion between the provinces watered by the southern 

 branches of the Ganges and the Deckan, including all the countries to 

 the south of the Nerbudda. From the north of this plateau, which 

 extends far to the west, a number of great rivers descend, by a series of 

 rapids and falls over sandstone escarpments, into the valley of the Jumna 

 and the Ganges. From the east and south of the same tract, the Maha- 

 nuddy river collects a great body of water, and after a comparatively 

 short course through countries little known, but containing the diamond 

 mines of Sumblepoor and extensive trap and gneiss formations, empties 



♦ See Plate drawn, eagraved, and described by Mr. James de Carl Sowerby, 



♦ The series of specimens presented by Mr. Malcolmson to the Geological Society 

 have been arranged in the foreign department oi the museum, 



♦ Asiatic Researches, vol. xviii. 



