538 J. G. Malcolmson, Esq., on the Fossils of 



this district extending 140 miles north and south, and having procured others 

 from localities to the north and west of that which furnished my own collection, 

 I am induced to submit the specimens to the Society*. If they should be 

 deemed of sufficient value, I wish a selection 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 f. 



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 valuable. They will 

 atford the means of connecting the great sandstone formations of the south 

 and north of India, containing the celebrated diamond mines of Parteal (Gol- 

 condah,) Bangnapilly, and Panna, as well as the limestones and schists asso- 

 ciated with them ; and which, from the latitude of Madras to the banks of 

 the Ganges, exhibit the same characters, 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 intro- 

 duction 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 de- 

 tailed, and the map attached to his memoir containing some errors of material 

 importance;};. 



General Sketch of the Physical Features, Hydrography, &c. 



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

 range of the Map, PI. XLVI.) may be considered as the geological 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 Mahanuddy river collects a great body of water, and after a compara- 

 tively short course through count; ien little known, but containing the diamond 

 mines of Sumblepoor and extensive trap and gneiss formations, empties itself 

 into the Bay of Bengal, not far south of the Delta of the Ganges. 



The Nerbudda, which flows in an opposite direction, is more interesting in 

 a political and geological point of view; and the extensive countries through 

 which it passes have been more carefully investigated than any other part of the 



* See Plate XLVIL, drawn, engraved, anddescribed by Mr. James de Carl Sowerby. 

 t The series of specimens presented by Mr. Malcolmson to the Geological Society have been 

 arranged in the foreign department of the museum. 

 J Asiatic Researches, vol. xviii. 



