PHYSICAL GEOGRAPHY. 37 



It is, however, noteworthy that these ridges are most continuous and 

 even-topped in the lower Vindhyan area when the beds are com- 

 paratively less disturbed and dips seldom rise above 6o° than in the 

 more highly disturbed transitions where dips of over 45 are the 

 rule and vertical dips are by no means uncommon. 



In part this is due to the greater disturbance of the transitions 

 and to the fact that the termination of the 



Connection between . . . e ,i 1 ,,- rv r ,1 



dip and form of scarp : ridges is frequently due to a cutting on or the 



Theoretical consideration. . 1111 r 1. «_ 1 . . -, • 



hard bed by a fault, but to a large extent it is 

 the direct result of denudation. To understand this let the case of 

 a hard bed among softer strata be taken and let it be assumed 

 that the hard bed is traversed by joints running at right angles to 

 the bedding planes, along which it breaks off ; the hard bed may be 

 assumed to stand at all angles up to vertical, while the softer beds 

 stand at an angle of only 30 ; further, we may assume that equal 

 amounts of the hard bed are removed in equal times and that the 

 surface contours of the soft beds protected by the hard one adjust 

 themselves to the altered conditions pari passu with the removal 

 of the hard bed. The conditions postulated are not very different 

 to those met with in nature, and the results obtained may be applied 

 with but little modification. 



n h 



Fig. 1. 



To commence with a condition of horizontality of dip, as 



represented in Fig. 1, it will be seen that the removal of a 



portion of the hard bed, H H, which will cause the surface 



contour to recede from 1 to 2, makes no change in the height of the 



( 37 ) 



