H) TRATS AND INTERTRAPPEAN BEDS 



1^/. — The enormous amount of denudation which has taken p^aee 

 since the trappean epoch, and which has swept away upwards of 2,000 

 feet of solid rock from the surface of the great Deccan plateau, would 

 have removed all trace of volcanic cones, if such had existed, as has 

 been shown by Carter and others. 



2nd. — This argument, I think, rests upon a fallacy : many sub- 

 aerial lavas are as compact as any other igneous rocks. But if any pecu- 

 liarity, more than anothei', is characteristic of the Deccan and Malwa 

 traps, it is their excessively vesicular nature. That the rocks are not 

 now vesicular is true, the hollows have been filled by silica, or by various 

 species of zeolites. But if the spaces, now filled by quartz, agate, or 

 zeolite, were not originally air bubbles, what were they ? Neither quartz, 

 agate nor zeolite could have existed as such in lava, whether sub-aerial 

 or sub-marine ; the water chemically combined with the zeolites would have 

 been expelled, and the chemical constituents of all have been fused and 

 combined with the mass of the rock. Finally, is it certain that sub- 

 marine lavas are not vesicular ? My own impression is that, although the 

 superincumbent pressure might diminish the size of the gas bubbles to 

 some slight degree, it could have no fm-ther effect, and I cannot see why 

 gas (usually water vapour) bubbles should necessarily be absent beneath 

 tiie sea. 



^rd. — I do not clearly understand the force of this argument. I 

 cannot see in what way the relation of the planes of bedding in the 

 traps to the bottoms of recent valleys proves more than that the present 

 surface is not identical with that which existed in pre-trappean times, 

 which is a matter of course. Probably Captain Newbold means some- 

 thing else, but he has expressed himself ill, and I can only confisss my 

 inability to follow his argument. 



4!fk. — The only spot in which marine organisms have been found 

 associated with the traps is close to Rajamundry, and their occurrence 



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