296 KECENT DEPOSITS OF NERBUDDA VALLEY. 



. Group (b). 

 This group, which covers a far more extensive area than the last, 

 consists of irregular beds of shingle, sands and conglomerates, passing 

 upwards into a thick deposit of pale brownish coloured alluvium : the 

 upper portion of which merges insensibly into a black soil identical with 

 the Regur so widely spread over Western India. 



The thickness of this group is not inferior to that of the last, but the 

 „,, . , „ , development of the coarser beds at the base of 



Thickness of the up- r 



per group. j nQ ser i e s is very variable and seems greatly in- 



fluenced by the amount of denudation the lower group has experienced 

 as when that has been inconsiderable the coarser beds of group (b) are not 

 met with, and the lower group immediately supports the upper alluvium, 

 but where on the contrary the lower group has been largely denuded, 

 as along the sides of the valley, there the course shingly bottom beds are 

 well represented and often attain a thickness of 30 or 40 feet. 



The alluvium, however, and Regur, is less capriciously distributed and 

 averages upwards of 20 feet, though in many places the Regur has 

 been entirely removed by atmospheric causes at present in action, which 

 during every monsoon carry away an enormous quantity from the flat 

 land bordering the Nerbudda,, which loss is to some extent made good to the 

 cultivator or to speak more correctly to the productive resources of the 

 country by the deposit of rich silt which the river on falling deposits 

 on its bank and within the embouchure of every creek and nulla flowing 

 into it. 



The old bed of the river above Narainpur affords an illustration 

 of the extreme richness of this river silt, and produces a wheat crop of 

 unsurpassed luxuriance. 



The lowest bed in this group is usually a conglomerate which varies 

 according to the nature of the rocks in the vicinity. Along the north 

 side of the valley it is chiefly composed of partially rounded fragments 

 of sandstone, the debris of the Vindhyan escarpment. 



