the Eastern Portion of the Basaltic District of India. 561 



has been injurious in leading geologists to admit too easily the existence of aqueous pressure, or 

 extensive denudations of solid rocks, supposed to have confined the carbonic acid at the time of 

 eruption. No doubt pressure is an efficient agent in some cases*, but not in many to which it has 

 been applied. 



The trap terminates in the line of section, a few miles to the north of the 

 city of Nag-poor, and is succeeded by a red sandstone, the strata of which 

 are bent, fractured, and converted into a compact quartz rock, at the point of 

 contact with the granite which has burst through it. Within a few hundred 

 yards of the ravine where these phenomena were observed, mica slate occurs, 

 and a httle beyond, some hills of gneiss. A bed of granular limestone is 

 quarried at the foot of a conical hill of basalt, in part composed of a scabrous 

 quartzose, and calcareous rock, abounding in drusy cavities, calcedonies and 

 cornelians. Further north, granite veins pass through a much-elevated lime- 

 stone, varying in colour from red to gray and black, and the stratification of 

 which is nearly obliterated. The gneiss and mica slate forming the neigh- 

 bouring hills are also penetrated by dykes and masses of granitef . To the 

 north of this district are 50 miles of a wild mountain country, composed of 

 granitic rocks, with trap in the ascents and tops of the passes ; the basalt then 

 reappears, and composes great part of the valley of the Nerbudda. 



In a direction south-west of Nagpoor, the nodular basalt is the only formation 

 met with as far as Baitool (90 miles), where granitic rocks reappear, but are 

 succeeded by fine-grained sandstones with traces of coal, and penetrated by trap 

 dykes ranging from S.E. to N.W;};. Here, the sandstone rises into mountains, 

 and constitutes what appears to be the continuation of the range forming the 

 division between the valleys of the Taptee and Nerbudda rivers ; and " indu- 

 rated clay," containing casts of the same shells as those of the Sichel range, 

 also occurs. 



Before proceeding to notice more particularly the fossils, and the evidence 

 they afford of the geological era of the intrusion of the basalt, it is necessary 

 to make some observations on the Sichel range, and the connexions of the 

 several formations occurring in the district described. The basaltic rocks of 

 Nagpoor and of the country to the south, have been considered by every ob- 

 server to form the eastern part of the great basaltic formation of Western 

 India, with which it is continuous, and with which it agrees in every particu- 

 lar of general character and mineralogical structure, and in being connected 

 with stratified rocks, which, as far as is yet known, are of the same age. The 

 only difference is, that towards the eastern limits of the formation, the hills are 



* Transactions of the Royal Society of Edinburgh, vol. vl., p. 120. 

 t Captain Jenkins, in Asiatic Researches, vol. xviii. 



X Lieuts. Miles and Finnes, Journal of the Asiatic Society of Bengal, Feb., 1834, and Dr. Spils- 

 bury, August, 1834. 



