194 



PROCEEDINGS OP THE GEOLOGICAL SOCIETY. 



whenever a river is in train (that is, when the water has got the 

 proper load of solid matter due to its velocity) it loses all power of 

 scour, be the velocity what it may. 



This opens out a large subject for investigation of vital import- 

 ance to hydraulic engineering ; but as the object of this paper is to 

 show what is at present going on, the better to enable us to form 

 an idea of what occurred immediately before the present state of 

 things, I will not discuss it. I have now to consider what has been 

 the last great exception to which I have alluded. Tbis is the up- 

 heaval of the Sewalik range, and the probable formation of the 

 deep valleys through which our large rivers flow. 



The accompanying section (fig. 3) shows by a dotted line, where 

 the Sewaliks are crossed, what was pi-obably the sui'face of the 



Fig. 3. — Diagravi Section through the Sewcdiks near Umhalla. 



Vertical scale 600 feet to 1 inch. Horizontal scale 12 miles to 1 inch. 



country prior to their upheaval. We have a remarkable corrobora- 

 tion of this curve-theory at Guneshpoor (B), which is a little over a 

 mile south of the hills : a well has lately been sunk, and water was 

 only reached at 120 feet below the surface of the dry or Babur 

 tract ; while where the dotted line is above the present surface is 



