C0RRASI0N BY GRAVITY STREAMS. 



237 



(d) Hanging Valley produced at by later and stronger stream 

 action. indicates the location of maximum action along 

 the cutting curve. 



(e) A Hanging Valley 

 where the location 

 of maximum cut- 

 ting action is situ- 

 ated down stream 

 of the Hanging 

 Valley lip. 



If, however, the axes of the confluent streams be not 

 symmetrically disposed to the axis of the main stream 

 [Fig. 5 (b)] then basining and the associated heaviest under 

 cutting of walls will be found facing the direction of heaviest 

 stream action as at R, Pig. 5 (b). The topographic con- 

 figuration will indicate which such direction will be in any 

 where the streams occupy considerable portion of their 

 valleys. 



(2) Corrasion on channel slopes. — Each stream has some 

 limiting channel slope along which it can but barely flow. 

 Any reduction in the angular value of this slope will cause 



