GEOLOGY. 



whists. 1 . In the Santal Parganans the Rajmehal traps he- 

 long to the Gondwana system, and are often interbedded 

 with coal and carboniferous shale. In the Bisrampnr coalfield, 

 in Sarguja, boulder beds of gneiss are characteristic of the lower 

 Gondwanas. Of the less important areas of Gondwana rocks 

 may be mentioned the Itkuri coalfield in northern Hazari- 

 bagh, one on the Balumath-Chatra road, and one called the 

 Chope Coalfield well on the Hazaribagh plateau at nearly 

 2,000 ft. elevation ! None of these is believed to be worked at 

 the present d ty. 



The low plateau of Singbhum is mostly metamor- 

 phic rock (gneiss) overlaid by a stiffish clay, and is much 

 intersected by trap dykes. The series best represented in 

 Singbhum however is the snb-metamorphic ; in fact all the 

 shief hill ranges are composed of these rocks. The sub- 

 •jaetamorphics . are principally quartzites, ferruginous and 

 mica schists, siliceous clay slates, shales and phyllite. 

 Haematite and other iron schists are very widespread ; whole 

 ranges {e.g., the Loknd Burn ridge in the Songra forest) 

 are composed of them. The clay schists are usually inter- 

 bedded with quartz laminae. On weathering, the latter break 

 up into numerous stones which often thickly strew the 

 surface. The clays derived from these schists are usually 

 very impermeable and are baked a stony hardness in the hot 

 season ; they support a poor forest growth often characterized 

 by the presence of Gardenia gummifera both in Singbhum and 

 in the protected forests of Manbhum. The 6oil derived from 

 the iron-schists and quartzites is usually better or, at any rate, 

 the forest growth is better, from the roots being better able to 

 penetrate the numerous clefts • and fissures which are 

 3haracteri8tic of these rocks when superficial. In Kun- 

 drugutu, and some other places, magnesian schists (patra diri, 

 Kol) are found, which are worked by the Kols into plates 

 and ornaments. Deposits of laterite in Singbhum occur in 

 Saranda in large amygdaloidal reddish masses especially about 



1 Ball, Memoirs of the Geological Survey of India, Vol. XVIII, Pt. 2. 

 12 



