STRUCTURAL GEOLOGY AND THE FORM OF THE GROUND. 21 



of the ridge. On the other hand, if the elevation here is referable to 

 the upper eocene period, as in the ease above alluded to, denudation and 

 removal of all the older tertiary sandstones, and the eocene, cretaceous, 

 Jurassic, and a portion of the triassic beds over a slightly raised area, 

 may be supposed to have locally taken place ; this area being then again 

 depressed and covered up by Siwalik deposits, subsequently denuded in 

 their turn, would account for present appearances. 



This extensive denudation of all the mesozoic and much of the 

 tertiary rocks would, however, involve the formation of thick local con- 

 glomerates of pre- Siwalik age which have not been discovered ; and 

 should this be a fatal objection to the above interpretation of the 

 case, it can only be supposed that the northern Khasor elevation is the 

 oldest yet recorded in the Salt Range region, and took place before the 

 deposition of the Jurassic rocks ; or else that the Jurassic deposition was 

 here suppressed, and the elevation took place at a later pre- Siwalik period. 



Still earlier disturbance of unknown regions largely formed of meta- 



Pre-carboniferous dis- morphic rocks must have enabled these to be 



turbance. fashioned into the smoothly-rounded boulders which 



fill the boulder beds below the carboniferous group of the Khasor range. 



There would thus be three or four separate periods of elevatory 

 disturbance traceable in this district, two palaeozoic, one mesozoic or 

 pre- Jurassic (?) and two cainozoic : of these one being post-eocene and the 

 other probably dating from later tertiary to post-tertiary times. 



How far subsidence may have affected the ranges, or even produced 

 some amount of local elevation, I refrain from discussing for want of 

 sufficient evidence to justify conclusions. 



Denudation. 



It need scarcely be observed that denudation has taken an important 



_ , . part in the sculpture of this region, removing- 



Denudation. r r . 



enormous masses of the mountains by processes 



which there is no evidence to show were other than those due entirely 



to atmospheric agency and which are still in action. 



( 231 ) 



