Chap. III.] the talchir group. 37 



Panuri. They do not re-appear further East: North of the Adjai, 

 near Kasta, Afzalpdr, and Has wan, a natural boundary extends for 

 about 12 miles, and along the whole of this distance the Damuda 

 series rests directly upon the gneiss, as was observed by Mr. Williams, 

 so that the Talchir beds are completely over-lapped. 



Two or three small patches of Talchir beds are brought in by the 

 faults forming the South-west boundary of the field. None of these 

 small areas present any features of interest. 



None of the sections above given illustrates the most singular pecu- 

 „ ,, , , ' liarity of the Talchir group, viz. the presence, 



so frequently referred to, of enormous boulders 

 of gneiss and other metamorphic rocks, in a matrix of the singularly 

 fine silty deposit referred to as mudstone. This boulder bed is 

 not very widely distributed in the Raniganj field, although boulders, 

 here as elsewhere, occasionally occur in the Talchir beds, especially 

 towards the bottom. The best development observed is seen North 

 of Panra, in the West of the field, and especially in the neighbor- 

 hood of the village of Chargora. Here the mudstones are purple 

 and greenish-grey in color, and break up, at the surface, into 

 extremely thin angular fragments, an inch or less in breadth, and from 

 jL to £ of an inch in thickness, with conchoidal surfaces above and below. 

 The only substance with which it can be compared is fine river silt- 

 Some of the beds are a little coarser, and occasionally thin bands of sand- 

 stone occur and form regular interstratifications with the mudstone. 

 Throughout these beds pebbles of all sizes and huge boulders are 

 scattered, the small pebbles being frequently few in number com- 

 pared to the large ones and boulders. Two boulders, which lay partly 

 broken, were measured; when perfect, they must each have exceeded 15 

 feet in their longest diameter, and have weighed not less than 30 tons. 



All the " boulders'''' are completely rolled and rounded. The majority 

 consist of varieties of metamorphic rocks common in the neighborhood 



