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conglomerates belong to the upper Gondwana age. The 

 ridge of gneiss from the basaltic plateau of the Deccan to 

 the Highlands of Chutia Nagpur is overlaid and crossed 

 by Gondwana deposits stretching across from the Son to the 

 Mahanadi. The watershed between the Son and the Maha- 

 nadi is pretty high and is occupied by Talcher rocks of no 

 great thickness, so that gneiss forms the rock barrier from 

 East to West. The Tributary mahals of Orissa also belong 

 to the Gondwana series. The coarseness of the rocks, the 

 prevalence of sandstones, the frequent occurrence of bands of 

 conglomerate and the absence of marine fossil, characterise 

 them as Gondwanas. 



31. Then come the typical Damuda or Barrakar rocks 

 belonging to the carboniferous system. The Barrakar river 

 and its tributaries traverse the whole of this region. It 

 passes round the western portion of the Raniganj coal-field 

 and falls into the Damodar within the limits of the field. In 

 the higher portion of its course the Barrakar receives streams 

 which drain the Karharbari coal-fields which are supposed 

 to be Talchers or the lowest Gondwana and not carboniferous. 

 Conglomerates, sandstones, shales usually micaceous, and 

 coal, characterise this region. The sandstones are felspathic 

 consisting of grains of quartz and decomposed felspa . 

 Knobs of calcareous concretions project through the sand- 

 stones. Felspar is at different places seen converted into 

 pure Kaolin. White felspathic sandstone may be traced all 

 the way from Raniganj to Chanda in the Central Provinces. 

 Another typical Barrakar rock is conglomerate of rounded 

 white quartz pebbles scattered over the surface of the soil. 



32. Last of all we have the Archaean rpcks of Bengal, meta- 

 morphic and submetamorphic, transition or Vindhyan. Small 

 hills in Bihar appearing through the alluvium are most of 

 them Lower Vindhyan and at the lowest level .where the 

 Ganges washes the base of the plateau at Chunar only Upper 

 Vindhyans are exposed. The concealment of the Lower 



