DUBRAJPUR GROUP. 45 



will appear in the course of the following- pages : 

 The lithological character; 

 composing the Dubrajpur group are as follows :- 



Lithological characters. 



The lithological characters of the principal rocks 



1. Conglomerate. — Consisting of quartz pebbles in a compact ferru- 

 ginous matrix. The mass is often traversed smoothly by joints. This 

 rock is precisely similar to one found on Panchet and Lagu hills. 



2. Conglomerates. — Less compact than the above. Owing to the 

 presence of decomposed felspar, and less iron in the binding matrix, the 

 pebbles readily fall out. Some of these conglomerates resemble the 

 beds which occur towards the base of the Barakar group. Similar beds 

 are by no means unknown, however, in the Mahadeva series. Another 

 variety of conglomerate which appears to be somewhat local, having 

 only been observed in the Dubrajpur range, contains, in addition to the 

 pebbles of white quartz, large pebbles of a deep pink-coloured orthoclase 

 felspar. 



3. Grits.— Generally highly ferruginous ; these pass into — 



4. Sandstones of several varieties of texture and color. 



5. Fine arenaceous beds passing into shales. — Some of these resem- 

 ble beds of the lower Panchet group in the Raniganj field. Similar 

 beds are not wanting, however, in the upper Panchets (Mahadevas), as, 

 for example, in the Garangi hill (Raniganj field). 



The total thickness of these rocks is not less than 400 feet, and 

 may be as much as 450. In one section, from the 

 river bed at Narganjo to near the top of the range 

 at Sudra, we have a thickness of almost exactly 500 feet of sandstones. 

 Prom this not more than about 50 feet should be substracted for the 

 portion of the sandstones referable to the Damudas. There is probably 

 no section in the whole area in which a greater thickness than 450 

 feet is exposed \ that amount, therefore, may with safety be regarded 

 as the maximum. 



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