PHYSICAL GEOGRAPHY, 45 



which bounds it in the north, running close to and parallel with the 

 river from Sasseram on the east to the sources of the Mahanadi. 

 Throughout this length of nearly 300 miles as also throughout its 

 continuation in the Narbada valley, it is not breached at a single 

 point by any stream flowing northwards, nor, with a few trivial 

 exceptions, by any stream flowing from the north to join the Son. 

 Everywhere it rises abruptly to a height of from 500 to over 1,000 feet 

 above the low ground at its foot, and though the height of the crest 

 varies from place to place, through undulations of the strata or the 

 varying amount removed by denudation, there is nowhere any deep- 

 cut gap or easy pass from the north to the south of this range. 



Such a feature is, so far as I know, unique in physical geography. 

 Escarpments of great length are known, but they are all breached 

 at intervals by streams which flow through them, usually, as in the 

 classic case of the chalk escarpments of the Weald, from the scarp 

 side towards the dip. These cross-valleys are almost a necessary 

 consequence of the current theories of the formation of escarpments, 

 which presuppose a plain or peneplain at a general elevation, greater 

 than the crest of the present scarp. Across this plain rivers were 

 initiated whose general course would be down the slope, that is to 

 say, usually in the direction of the dip, and as they gradually cut 

 their channels down their side streams would more rapidly attack 

 the soft beds, wearing them away and leaving the harder beds 

 standing out as scarps. 



In the Son valley and the Vindhyan plateau to the north we have 

 a generally north, that is, dip- wards course of 



Northward trend of . 



drainage interrupted by the drainage ; we have also the Kaimur scarp 



the Kaimur scarp. " 



due to the removal of the softer beds of the 

 lower Vindhyans and the standing out of the harder upper Vindhyan 

 sandstones ; but instead of any of the northward flowing streams 

 continuing their course through gaps in this scarp they are one 

 and all intercepted by the principal river of the district, which 

 flows along the foot of the scarp. Not only is this the case as 

 regards' the actual course of the drainage, but there is no 



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