AURUNGA FIELD : BARAK AR, GROUP. 65 



overlaid by grits, sandstones, and blue and grey shales. At Hureyakur, 

 ironstones, of which we shall have more to say presently, are seen in the 

 banks of the stream. Soon, by interpolation, the highest beds of the 

 carbonaceous zone make their appearance, and steadily increase in dimen- 

 sions, and vary in character as we proceed down stream in a north-west 



direction. There are, at least, three distinct seams 



Seams at Jomean. 



near Jomean with low rolling dip to south-west* 

 To the north-west of Jornean again there are two more, the position of 

 which with regard to the ironstones about to be described is uncertain, 

 owing to the complications of the stratigraphical sequence arising from 

 extensive interpolation. 



Overlying the carbonaceous zone is a band of shales, with ironstones, 

 which form a very marked north-west to south-east 

 R^bSf °'''' '°''*^ ""* ridge for a distance of nearly two miles. From a 

 section afforded by a stream south of the ridge, I am 

 inclined to believe that, as a maximum, the ironstones are about 10 per cent, 

 of the whole thickness of this zone. The actual thickness of the zone 

 is somewhat doubtful, but as the average dip of the shales is about 5®, 

 200 feet is, I think, a fair estimate, so that where thickest there is prob- 

 ably a total of 20 feet of ironstones. At first sight, owing to the fact that 

 the conservation of the ridge has been due to the presence of the iron- 

 stones, and that fragments of ironstone strew the surface in great abund- 

 ance, it might be thought that the above was an under estimate, but 

 I believe it to be a most liberal one. Now, as to lateral extension : to- 

 wards the south-east the ironstones, like the carbonaceous shales, appear to 

 die out rapidly. To the north-west at Jornean the ironstones are locally 

 elevated into an anticlinal; their further prolongation is doubtful; 

 a sharp turn to north of Jornean would bring them into connec- 

 tion with the zone at Kolherwan, but the occurrence of the seams 

 north-west of Jornean renders it probable that these are continued 

 and die out in the direction of Timkee, and that therefore the two 

 zones are really distinct, being interpolated at slightly different 

 horizons. 



( 65 ) 



