BARAK AH GROUP. 41 



nary forms of sandstone grits and conglomerates all occur, and huge seams, 

 consisting largely of carbonaceous shale, are found at various horizons 

 and with most irregular lateral extension. As will be amply exemplified 

 in the detailed sections which are given below, the irregularity in the 

 deposition of the various Barakar beds was extreme. Internal overlap 

 exists on a large scale being very clearly shewn in certain closely ad- 

 jacent sections, where beds are seen to thin out or expand, as the case 

 may be, with extraordinary rapidity. The bottom beds are usually 

 conglomerates, with small rounded pebbles of white quartz. Occasionally, 

 however, these are replaced by what would be more properly denomi- 

 nated as breccias, the fragments of quartz being sharply angular and 

 quite unworn, in this respect resembling some of the coal-measm-e 

 conglomerates of the Karharbari field. In the eastern parts of the field 

 these lowest beds are often covered by white and pinkish, somewhat 

 clunchy, clays. Occasionally, too, there are dark-red clays at about the 

 same horizon, but sometimes these last occur at the very base, in which 

 eases they might very probably be taken as belonging to the Talchir 

 group, from which however they must, I think, be separated. 



Above this lower zone comes one of variable thickness, consisting 

 of sandstones, carbonaceous shales and ironstones,which extends up to the 

 base of the Raniganj group. In the sandstones next adjacent to the 

 conglomerates concretionary masses of brown or red hsematites occur 

 in considerable abundance. These are covered by an irregular sequence 

 of carbonaceous shales (with coal), ironstones and sandstones, which in 

 some instances, as at Toobed on the north, and in 

 some of the sections of the Aurunga and Ghugree 

 on the south, have completely overlapped both the iron-bearing sand- 

 tones and the conglomerates of the lower zone, and rest directly and 

 naturally on the metamorphic rocks. 



In the neighbourhood of Latiahar this upper zone has a very much 



diminished thickness, and west of the Aurunga has 



wholly disappeared, for we find there that the 



Mahadevas rest directly on the lower conglomerates. How far this 



( 41 ) 



