Chap. TV. § 4.] raniganj group. 77 



depth passed through four seams, amounting in the aggregate to a thick- 

 ness of 18 inches of clay ironstone, and 52 inches, in two seams, of 

 black band, all of good quality, besides 18* inches of inferior black band. 

 This gives T a ¥ of black band, and -^ of clay iron ore, altogether 

 about ^ ; but the inferior richness of the black band would render the 

 quantity of iron extracted from the ore obtainable from a given area 

 very little larger than in the case of the other section above quoted. 



One note-worthy circumstance, which would be of great advantage 

 in mining these beds, is their impermeability to water. Mr. Smith's 

 shaft, after standing open for three years, had only a few feet of water 

 at the bottom : almost every where else throughout the field, shafts, 

 after being left for a season, fill with water. 



Black band or carbonaceous clay iron ore is by no means rare 



throughout the ironstone shales, though the shaft at 

 " Black band " ore. _, .. f . T11 , . i . , 



Joadul probably supplied an exceptional case of its 



abundance, as in general there is less of it than of the ordinary clay iron 



ore. Considerable quantities occur around Birkunti, North of BaduL 



Chapter IV., Section 4. — Raniganj Series. 



The large area upon the map occupied by the rocks of this group, 



and the number of coal seams worked within its 

 Sub-division into districts. 



area, render it necessary to sub- divide it some- 

 what before proceeding to describe its local peculiarities in detail. In 

 the same manner as with the Lower Damuda, the most convenient plan 

 appears to be to commence the description on the East. The tract 

 lying North of the River Damuda will be treated of before the area to 



* Mr. D. Smitb says 38 inches, but this comprises three seams of 8, 9, and 3 inches respect- 

 ively, which were not intersected in the pit. 



