NERBUDDA DISTRICT. 191 



3 feet respectively. These are not " silicified " but regularly fossil- 

 ized by the sandstone itself. The replacing material is coarse, and the struc- 

 ture of the wood but feebly traceable. The medullary rays and bark of an 

 exogen are however distinctly recognizable. 



It is certain that the lower Damudas were largely denuded before the 



, i. ., n ., deposition of the Mahadevas, and it is, at all events 



.Lower limit of the * ' 



Mahadeva. possible, that even the upper Damuda may have 



also been disturbed and denuded before the same period : in spite of this 



the tracing out of the lower limit of the Mahadevas has been found a 



work of great difficulty. This subject has been already enlarged upon 



when the boundaries of these lower formations were under discussion ; 



and in describing the Hurd coal section it was 

 Hurd River section. # 



pointed out that the massive sandstone beds which 



interstratify with the coal and shale bands are undistinguishable from 



those of the Mahadeva group themselves. Higher up the Hurd a 



thick bed of sandstone, apparently Mahadeva sandstone is seen, near 



the villages of Cachar and Monighat, resting 

 Monighat section. 



on a series of flags, shales, and thin-bedded sand- 

 stones with plant impressions, and which seem naturally to find their 

 place in our Upper Damuda division- The thick sandstones seem to 

 pass up into the great mass of the typical Mahadevas, and altogether it 

 seems pretty certain that here at least, we have the division line between 

 the two formations. — But in many ways this line is very ill defined; 

 a kind of pseudo conformity is preserved, and no definite difference of 

 lithological character exists. — However the general prevalence of such 

 conditions may increase the difficulty of laying down accurately, in detail, 

 the position of the line of demarcation between the Mahadeva and the 

 lower and upper Damuda groups, in some places, yet this unconformity 

 on the great scale already noticed, and the great differences in the 

 lithological characters of the groups taken as a whole, amply make up 

 for this deficiency of precise evidence in individual cases. 



