Chap. V.] post-sivalik deposits. 157 



rocks, except in the extensive sinking of the central mountain region ; 



there is reason to think the action has been long continued and even 



intermittent. 



Though, on the whole, these local surface-deposits of the duns seem 



to be more ancient than the Gangetic formation, 

 Lakes. 



we may find among them links of connection with 



modern deposits ; there are still left some small lakes, now basins of 

 deposition, which, I believe, owe their origin to the same causes as may 

 have spread deposits over some of the inner duns. The lakes of Kun- 

 dulu and of Morni are both situated just inside the boundary of the 

 middle and upper Sub-Himalayan groups. The Kundulu lake is 

 evidently only a deep mountain gorge, stopped up towards its lower 

 extremity ; and just here we find an axis of contortion. This lake has 

 been much deeper than now ; there is about half a mile of sloping delta 

 at its upper extremity, which probably contains older beds than any now 

 to be found at the surface of the Gangetic plains. It must not be 

 forgotten that we have already proved the existence of the actual 

 drainage lines or valleys, in the rocks of the older groups, prior to the 

 Sivalik period. There are at many places remnants of such detached 

 lake-deposits ; one of the most interesting I could mention is that among 

 the slate rocks of the Lower Himalayas, about Haut, a few miles north- 

 north-west of Subathu ; it forms several square miles of level ground. 

 The ravines of this area are cut through about 200 feet of clay 

 and sub-angular gravel without reaching the rock. The sacred lake of 

 Rurka, north-east of Nahun, lies in an abandoned portion of the bed 

 of the Giri ; this river having effected a new confluence with the Jalar, 

 and adopted the course of the latter. 



In connection with the subjects s&- briefly touched upon in the 



preceding paragraphs some mention should be 

 Rivers. . . 



made ol rivers. It is only of late years that 



rivers have met with the attention they deserve as indicators of changes 



