<fO OLOCY OF THE SON V ALLEY, ETC. 



The rock forming the thick continuous bands is usually highly 

 crystalline and much coarser-grained than any of the Vindhyan 

 limestones. They are nearly always conspicuously striped or mottled 

 (see specimens T y ¥ , tVV)- 



The limestone interbedded with the red jasper at Agori Khas 

 (spec. -J-^j) shares the red tint of the jasper itself, similarly due to 

 the presence of hematite which gives the rock a very high density, 



3-0,1. 



Section III.— Volcanic rocks, 



a. — Stratigraphy. 



The most characteristic members of the Bijawars are the basic vol- 

 canic rocks. 



In the Son region they are confined to the Agori stage, their 

 greatest development coinciding with the horizon richest in jasper. 

 But they are also frequently interbedded with the strata that appear 

 to underlie that horizon. Where the Bijawar outcrop is broadest, 

 they are absent from the central portion of the outcrop, which pro- 

 bably represents a higher horizon. In map 481, where strata pre- 

 sumed to belong to the Agori stage reappear along the southern 

 boundary, owing to the synclinal nature of the Bijawar outcrop, 

 no volcanic beds are seen to occur at least in the portion which 

 I have examined. This absence may be due to the irregular distri- 

 bution of the rocks : the outcrop of the Bijawars is here very wide, as 

 much as twenty-five miles, and, taking into account the amount of 

 compression which they have suffered, this width answers perhaps to 

 as much as three or four times the original distance at which the beds 

 were deposited, and this leaves plenty of room for horizontal 

 variations. 



West of the Gopat where the Bijawar outcrop becomes much 

 narrower, volcanic rocks are freely developed in the neighbourhood of 

 the southern boundary, just as much as near the northern one, and 

 in fact throughout the whole width of the outcrop. 



Eastwards of the region which I examined in map 481 of Rewah, 

 I 70 ) 



