STEVENSON— INTERRELATIONS OF FOSSIL FUELS. 415 



ing on gneiss. It has a bowlder bed on top and its shales and sand- 

 stone often have rippled surfaces as well as obscure impressions, 

 suggestive of footprints. No coal v/as seen and the plants, which 

 are not abundant, belong mostly to Glossopteris and Cyclopteris. 

 The Lower Damuda (Barakar) has coarse to conglomeratic white 

 sandstone at base, succeeded by coarse, micaceous shaly sandstone 

 with seams of coal and shale, often thick. " These seams are ir- 

 regular both in thickness and in quality ; they frequently disappear 

 entirely or pass into shale or even sandstone within short distances." 

 The Lower Damuda is about 2,000 feet thick, a notable decrease 

 from the Jheria field, where it is about 3,300. The ironstone 

 group, overlying the Lower Damuda, is about 1,200 feet thick and 

 contains no coal. The Upper Damuda (Raniganj) consists of sand- 

 stone and shale without conglomerate ; its coal seams are less irregu- 

 lar than those of the Barakar. The whole of the Lower Gondwana 

 to the top of the Panchet is practically conformable, the apparent 

 lack of conformity at some localities being due to overlap. 



The Barakar coal seams are, for the most part, poor in quality 

 but vary in that as well as in thickness. At one locality, in northern 

 part of the field, is a seam, 34 feet thick, with three benches of coal, 

 7, 14 and II feet, but the coal is poor and slaty except in one part 

 of lowest bench. This great deposit can be traced for only a short 

 distance and it thins away rapidly in all directions. Many thick 

 seams were seen west from Barakar River. " These seams, how- 

 ever, seldom appear continuous over the whole area of the field ; 

 they can often not be traced for more than a few hundred yards and 

 the quality of the coal may (and in general does) vary within even 

 shorter distances." In one case a seam, 13 feet thick, divides into 

 two within 50 yards, and the lower division soon is replaced with 

 sandy shale. At times, sandstone and shale replace the coal for 

 considerable distances. " Ballcoal " is not rare and the concentric 

 laminse are crossed by laminae of the enclosing coal. 



The Raniganj seams are less irregular and contain less shale. 

 Blanford saw one 22 feet thick which was without parting, but ordi- 

 narily there are two or more benches. As a whole, the coal of this 

 formation must be regarded as inferior; the 17 analyses show 8.50 

 to 35 per cent, of ash; only two samples had less than 10 and 6 had 



