148 NERBDDDA DISTRICT. 



evidently been removed by denudation from above them, and they 

 always occupy the lowest ground among the hills formed of these newer 

 rocks. 



In describing this series lithologically we shall make use of the follow- 



General lithological m ° sub-divisions, which are based upon the most 



.scrip ion. prominent and important characters, found best 



developed, in the majority of the sections examined. They will be found 



useful for reference, in subsequent and more detailed descriptions, and 



show at a glance the principal features of the group. 



(a) Obscurely bedded, or imbedded masses of green mud ; occa- 

 sionally finely laminated, and frequently showing besides a char- 

 acteristic and very complicated jointing. 



( b) The green mud of (a) becomes sandy, or even gravelly. In 

 proportion as this character obtains, the shaly lamination dies 

 out, and the rock seems also to be then unaffected by the peculiar 

 jointing. The rocks included in this sub-division (Z>) tend to 

 pass into an earthy sandstone with distinct bedded structure. 



( c) Sub-divisions (a), and (b) pass into each other and either indiffer- 

 ently underlies the other : embedded either in the fine silt of (a\ 

 or in the more sandy mass of (b), there are frequently found in 

 great numbers rounded blocks of gneiss and granite, sometimes 

 mere pebbles, but often attaining great size. A maximum 

 diameter of 5 feet 8 inches has been measured, and 4 feet 6 inches 

 is a common size. This sub-division has been called the " Boulder 

 Bed." See Cuttack Report. 



(d) Green, grey, and blue shales with and without carbonaceous 

 markings. 



(e) Flags, green and grey, often very carbonaceous. 



(f) Coarse grey, brown, and red felspathic sandstones. 



The sub-divisions a, b, and c may be considered as the representa- 

 tives of the Talcheer group; d, e } and /of the lower Damuda. 



