GENERAL CONSIDERATIONS. 125 



me very strongly to accept the view that the southern edge of the hills 

 at the present day is a limit of disturbance in that direction, and that 

 it was so during the ages when all the different stages of the Sub-Hima- 

 layan series were deposited. Thus I conclude that quiet and unin- 

 terrupted deposition was ever going on south of the southern border 

 of the elevated land or mountain area, and that progressive slow and 

 regular crushing was taking place north of that border. It can 

 readily be seen that, by these processes, the apparent anomaly of 

 great unconformability between the uppermost and lowermost beds 

 of the series at one point, and of regular conformable sequence 

 through that series at another, is accounted for — the great interval 

 of time required for the deposition of the conformable series being 

 represented by the gap in time implied by the unconformability. 



The same reasoning would lead one to suppose that though the 

 Recent gravels and slluvium of the river terraces are seen in many 

 places to lie unconformably upon the edges of Siwalik strata, they may, 

 nevertheless, be conformable to, and pass down into, the latter a little 

 distance away to the south of the edge of the hills. The conditions 

 for bringing about this state of things, when brought to their lowest 

 terms, are simply a sinking or under-thrusting of the plains at the 

 foot of the hills and a rising or over-thrusting of the hills themselves. 

 Another and a very burning question is, how far the disturbances 

 The disturbance of the evinced by the Sub-Himalayan zone are repre- 

 not fe^resYrftative ^? sent ed in the older Himalayan rocks. It is 

 that of the older rocks. consta ntly assumed by many geologists in Eng- 

 land that the immense contortions and inversions of the Sub-Hima- 

 layan formations express, in themselves, all the machinery of up- 

 heaval and contortion of the great Himalayan chain itself. This is 

 a point I cannot concede. Even if, as is often assumed, the Himala- 

 yan and Sub-Himalayan sets of rocks shewed a perfect parallelism 

 in their lines of disturbance, I should still be unable to subscribe to 

 it. But, in the first place, such a parallelism does not exist every- 

 where. Over a great part of Kumaun there is a direction of strike 

 running north and south. It begins in a set of basic volcanic and 



( 183 ) 



