IN THE INDO GANGBTIC MOUNTAINS. 4,07 



the great Himalaya system on one side, and the table land of Malwa on 

 tlie other, bounded, too, by rocks that are always found associated with the 

 Coal measures, it does not appear improbable that a valuable deposit of this 

 mineral may yet be found somewhere between the line of secondary sand- 

 stone described in this paper, and the primary sand-stone, which makes its ap- 

 pearance at Dehli and other places. But, for the full and correct consideration 

 of this question, data are still wanting. The above are the containing rocks 

 of the Coal formation ; it being never found above the one or below the other, 

 and in this fact, combined with the configuration of the surface, are contained 

 the true grounds on which the discovery may be looked for. Certainly not in 

 the occurrence of the trifling veins and seams above noticed. 



The grey-wacke formation being considered, by most Geologists, as 

 synonimous with the old red sand-stone, the occurrence of Coal, under- 

 neath the former rock, does not invalidate the truth of the opinion, which 

 assigns a fixed place to the Coal measures in the general arrangement of for- 

 mations. It would appear, however, that the Coal found subordinate to grey- 

 wacke is, generally, of the non-bituminous species. Another fact connected with 

 the occurrence of Coal, as associated with this rock, is the prevalence of trap 

 rocks. In the Indo Gangetic tract of mountains, grey-wacke supplies the 

 place of the old red sand-stone, lying immediately on the rock described in 

 this paper, believed to be the new trap rocks, which have not, however, yet 

 been traced to any extent, although there are certainly indications of them in 

 more than one place. The Coal found in the Balta does, certainly, lie very 

 near the junction of the two rocks, and there are undoubted trap rocks in the 

 immediate neighbourhood. In particular, I may enumerate a green stone, 

 a felspar porphyry, and a porphyry, with a greenish grey basis, almost compact, 

 with imbedded crystals of felspar. These circumstances bear some kind of 

 resemblance to those described, as belonging to the Welch coal-fields j but in 

 the greater elevation of our grey-wacke, and the absence of every thing like a 



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