GEOLOGY OF THE SON VALLEY, ETC, 



Chapter X.— THE COUNTRY EAST OF LONG. 82° 3 a' E. 

 (R. D. Oldham.) 



The main area of the lower Vindhyans east of Long. 82° 30' to the 

 eastern boundary of Revvah territory no longer 



Lo\ter Vindhyan. J J ° 



presents the normal succession seen to the west. 



The porcellanites can be traced to near the Son at Gangi, though 



they are much less developed than to the west, and a larger 



proportion of the beds included in this stage are distinctly shaly. 



At Hurma the outcrop of the lower Vindhyans narrows down ta 



not more than a mile in width, and as the section 



Section at Hurma. 



here marks the disappearance of the porcellanite 

 stage, which is only picked up once some 28 miles to the east, deserves 

 detailed notice. Along the south bank of the Son,, opposite Hurma, 

 there is an exposure of coarse grained quartzitic sandstone very simi- 

 lar to the basement beds of the lower Vindhyans. Traced eastwards, 

 however, it forms a low ridge which can be traced to an exposure in 

 the stream which flows northwards past Khattai. Beyond this 

 the rock is seen at intervals and can be shown to belong to the trans- 

 itions and not the lower Vindhyans, both by being associated with 

 slates of transition type and by the exposure of the basement bed of 

 the lower Vindhyans in its neighbourhood. 



On the section south of Hurma the basement bed is not seen, but a 

 low ridge west of Khattai runs down into the Son and there is exposed 

 with an east-and-west strike and a thickness of 250 to 300 ft. It is 

 underlaid by 30ft. of greenish grey shales and overlaid by a similar 

 rock. The lower shales gradually pass into the sandstone, of which 

 over 50 ft. are exposed, the base of the series not being seen, 

 though it is probable that these sandstones are part of the basement 

 beds and not far removed from the junction with the older rocks." 



On the north bank Mr. Vredenburg describes the section in the 

 stream west of Hurma. Underlying the limestones of the Rhotas 

 stage is a bed 30 ft. thick of hard sandstone, not unlike that of the 

 { 162 ) 



