1837.] 



Geology of the Deccan. 



369 



Rajmahl hills in latitude 25 » and longitude 88<> to89«>E. as trap; 

 the latter says the basalt is of amazing thickness. The Rev. Mr. 

 Everest,* in a journey from Calcutta to Ghazipoor, passed four distinct 

 broad beds of trap between the parallels of north latitude 2'^o and 24°, 

 and longitude 84° and 87°. He states these beds to have an inclina- 

 tion to a common axis, and he thinks it probable they are connected 

 beneath the granite and gneiss. Mr. Royle travelling the same route, 

 observed the same beds. Mr. Everest's diagram shows their longitudi- 

 nal axis on a line between the Rajmahl hills and the sources of the 

 Nerbuddeh and Soan rivers ; and as the trap of the Vindhya range 

 and Sagar extends towards these sources, it is very probable the ra- 

 mifications are connected with the beds (seen by Mr. Everest) and the 

 Rajmahl hills, forming a belt across India from the 73° to the 89° of 

 longitude, extending, in fact, from near the mouth of the Nerbuddeh 

 river to the Ganges at Rajmahl. The southern limit of trap is much 

 lower than is assigned to it by Mr. Calder,f as Dr. Voysey describes a 

 basaltic dyke at Seringapatam, in latitude 12° 26'; and Mr. Calder 

 himself mentions partial deposits of overlying rocks as far south as 

 Cotallum, at the extremity of the great western range, between the 

 parallels of latitude 8« and 9°. Mr. Babington, passing through 

 Mysore, describes all the black rocks he met with as hornblende pass- 

 ing into basalt. He evidently adverts also to nodular basalt.^ 



Age of Trap. — With respect to the age of the great trap formation 

 of India, it would appear from Major Franklin's Memoir on Bundel- 

 kund, that its northern extremities rest on sandstone, which he consi- 

 ders identical with the new red sandstone of England; the trap would 

 therefore be posterior to the carboniferous series and belong to the 

 supermedial order. But the Rev. Mr. Everest§ adduces valid reasons 

 for questioning the correctness of Major Franklin's opinion ; and it 

 may be inferred, that he is doubtful with respect to the exact equivalent 

 in Europe of the Indian sandstone, as it is much associated with the 

 primitive rocks. || In fact, where are the oolitic rocks above, and the 



* Gleanings of Science, vol. iii. p, 135. 

 + The limitation of trap by Mr. Calrler of course i3 only intended by him to be 

 understood as of a continuous formation : basaltic dykes, and veins, of every shape 

 and size, being universally found in S.India. (See Dr. Benza's geological papers in 

 Nos. 12, 13 and 14 of this Journal). Editor Madras Journal. 



% Geo. Trans. 1st Series, vol. v. p. 325. 

 \ Gleanings of Science, vol, iii. p. 211, |j Gleanings of Science, vol. iii. p. 213, 



