COUNTRY BETWEEN THE KOTAH AND PATLI DfJNS. 47 



extending some way up the sides of the gorges, the Nahan sand- 

 stones and shales present a very high dip of 70 or 8o° immediately 

 north of the fault, and lowering to 30 or 40 further away, the direc- 

 tion of dip being the same as in the conglomerates. There is thus 

 a most manifest unconformability between the Siwalik conglomer- 

 ates of the triangular chaors, and the Nahans of the stream-beds 

 between them (see section V). The chaors and their composing con- 

 glomerates tail off in the bottom of the Dhangari and Sanguri sots 

 where they come to an end, partly by what is apparently a limit of 

 deposition, and partly by another small fault. There is, at first sight, 

 a suggestion of doubt as to whether the conglomerates here so mani- 

 festly overlying the Nahans can be of Siwalik age ; but on mature 

 deliberation I see no reason why they should not be. They are in- 

 clined at a low angle, and extend to such heights as to preclude 

 their being of Recent age ; not to mention the difficulty of finding 

 any Recent river to account for them. The fact of their immedi- 

 ately overlying the Nahans unconformably indicates that there must 

 have been considerable overlap of them above the sand-rock form- 

 ation, inasmuch as the latter, on the other side of the ridge to the 

 south, passes conformably beneath them. The high angle of dip in 

 the Nahans denotes considerable disturbance of them prior to the 

 depositing of the conglomerate above them. 



At the same time, though I believe them to be of Upper Siwalik 

 age, that is to say, continuously laid down with the regular main mass 

 of the undoubted Siwalik conglomerate, it is certainly the case that 

 they must represent the very uppermost beds of that age, and as 

 such probably approach in point of time as near to the present day 

 as they do to the age when the sand-rock was formed, on which they 

 lie conformably. It does not seem to me to be in accordance with 

 the natural laws of deposition to assume always a long interval of 

 time between two sets of strata which are unconformable to one 

 another, and to grudge a sufficiency of time for the deposition of 

 two thick but conformable rock stages. I am inclined to think, on 

 the contrary, that we have a better gauge in the thickness of the 

 deposits themselves than in the fact of unconformability between 



( 105 ) 



