86 



On t'he Fossils of the Eastern Portion 



[July 



some of tbem better than the theory of pressure, which, however useful 

 in removing the prejudices against the igneous origin of the trap rocks, 

 has been injurious in leading geologists to adujit t- o 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 pres- 

 sure is an efficient agent in some cases*, but not in many to which it has 

 bee a applied. 



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

 the city of Nagpoor, 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 hns burst through it. With- 

 in a few hundred yards of the ravine where these phenomena were ob- 

 served, mica slate occurs, and a little beyond, some hills of gneiss. A 

 bed of granular limestone is quarried al the foot of a conical hill of basalt, 

 i n part composed of a scabrous quartzose, and calcareous rock, abound- 

 ing in drusy cavities, calcedonies and cornelians. Further north, granite 

 veins pass through a much-elevated limestone, varying in colour from red 

 to gray and black, and the stratification of which is nearly obliterated. 

 The gneiss and mica slate forming the neighbouring hills are also pene- 

 trated 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 re- 

 appear, 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 valleyc of the 

 Taptee and Nerbudda rivers ; and " indurated 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 evi- 

 dence 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 



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

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



% Lieuts. Miles and Finnes, Jourual of the Asiatic Society of Benffal, Feb., 1834, and 

 Dr. Sf ilsbiiry, August, 1834. 



