MALLET, VINDHYAN SERIES. 7S 



northern^ and southern ridges are the remnants of a g>reat anticlinal, 

 the arch of which has been removed by denudation, and the space 

 between them is occupied by Lower Vindhyans ; which are, however, but 

 rarely seen above the alluvium. 



North of Singrampur the Rewahs come to the surface again in the 

 form of a low dome, which is surrounded in succession by the various sub- 

 divisions of the lower Bundairs. The harder of these, the limestone 

 and lower Bundair sandstone, form a circle of hills with steep 

 scarp-Hke slopes inside and a moderate inclination towards the exterior. 

 A local fault brings the Eewahs and Bundair limestone almost in 

 contact on the north. 



The boundary between the Rewahs and Bundairs east of Kuttungi 



appears to be a faulted one. The latter are not seen close to the ridge, 



the vicinity of which is occupied by alluvium, but where the same junction 



is exposed further south-west, it is an undoubted fault. Another argument 



may be derived from the physical features of the country. It is a 



weU known fact that where hard and soft strata alternate with each 



other, where denudation has acted extensively, the hard beds when 



thrown up at an angle tend to form hills, and this tendency increases with 



increased inclination. The circle of hills north of Singrampur is a 



remarkably good example of this. Here the Bundair limestone and lower 



sandstone are included between the upper and lower shales, and although 



only thrown up at angles of 10 or 15 degrees they form an almost unbroken 



cii'cle of hills along their outcrop. Now, if the boundary east of 



Kuttungi be supposed to be a natural one, the lower Bundairs must be 



inclined at nearly the same angle as the Rewah sandstone, or from 



60 to 90 degrees. In this case, one peculiarly favourable to the harder 



* The northern ridge is known to the people of the district as the " Kymore," but as it 

 is formed of Eewah sandstone, it might lead to confusion to adopt this name here. The 

 southern ridge also is called " Keinjua," a range which in the Sone valley is composed of 

 lower Vindhyans. 



{ 73 ) 



