Chap. IV.] nahun and sivalik groups. 115 



over the fine lignite sandstone, near the inner boundary, the dip 

 of the whole section being 80° to north-north-west. Notwithstanding its 

 considerable thickness, I could not find a trace of it in the similar gorges, 

 to east or west. 



The lignite sandstone shows prominently for some way beyond Nahun 

 to the west ; about the Morni lakes it is very well exposed. In this 

 neighbourhood we find one of the few instances in which this rock comes 

 in contact with the similar rock of the Subathu group. The contrast in 

 the texture is most striking : on the gap just south of Morni one steps 

 at once from the hard angular debris of older rock to the rounded sandy 

 surface of the newer. 



In the Figures 12 and 16, the general condition of the Nahun rocks is 

 Disturbance of the Na- sufficiently indicated ; the strata are usually more 

 inclined than in the sections there represented, 

 being often vertical throughout nearly the whole thickness of the band. 

 The dip is, with few and only local exceptions, towards the older rocks. 

 The underlie of the plane of contact can be well seen in some of the 

 narrow gorges below Masuri, pointing steadily northwards, thus producing 

 abnormal superposition. There is a very peculiar feature in the horizon- 

 tal outline of this boundary, as exposed in the eastern portion of the 

 Dehra dun, namely, its sharp bends. I have already appealed to this fact 

 as almost precluding the supposition of this boundary being one continuous 



. , fault of enormous throw, but there is a supple- 



Steps m mam boun- ±r 



dary not cross faults. mentary supposition by which that view might still 



be maintained ; — the sharp step-like form of these irregularities suggests 

 the existence of cross-faults. We do not, however, find a single fact of 

 detail to corroborate such a view. In that marked example of the 

 Kalunga ridge, east of Kajpur and Dehra, the boundary runs directly for 

 five miles to north-by-east, at right angles to the direction of the Masuri 

 ridge, at about its middle, the angle of the boundary being only four 



