364 AVIFAUNA OF CHOTA NAGPUR. 



In these western districts there are some ancient valleys in 

 the gneiss which are now filled with boulder beds; and 

 as the boulders consist to a considerable extent of indurated 

 sandstones or quartzites of apparently Vindhyan age, and 

 resembling those seen near the Sone, the conclusion that these 

 were channels through which the glaciers entered from the 

 north, seems a just one to draw. 



Overlying the Talchirs the next formation is known as the 

 Damuda, of which there are three sub-divisions or groups. 

 The lowest of these is the Barakar — so called from its having 

 been first discriminated in the vicinity of the river of that name. 

 In this group, which has a very wide distribution throughout 

 India, and is characterised by certain fossil plants, occur the 

 lai'gest coal seams known in the country, and indeed there are 

 occasionally seams found in it, which for their size, if not their 

 quality, stand almost unrivalled in the world. Except in some 

 of the Damuda valley coal fields most of the coal found in India 

 belongs to this group. 



Above the Barakar group there is found one consisting of 

 carbonaceous and ironstone shales. This, like ' the one which 

 follows, shows its greatest development in the Raniganj 

 field. 



The ironstones are possibly destined to play an important part 

 when the mineral resources of India come to be developed. 



The Raniganj group consists of sandstones, shales and coal, 

 and exhibits its greatest development in the Raniganj coal field. 

 Towards the west it gradually dies out and disappears. 



In the Raniganj coal field this group contains the finest coal 

 seams which are worked in that area. 



Resting upon these is a series of beds known as the Panchet 

 from a well-known hill which is formed of these rocks. 



The lower group of this series contains certain fossil remains 

 of reptilian and batrachian animals which serve to point its 

 affinities to the Triassic period of Europe. 



The conglomerates and sandstones of the upper group form 

 several well marked hills, of which Beherinath, Panchet, Lugu, 

 and Mudi are the principal and best known. The last men- 

 tioned, which is situated in the Karanpura valley in Hazari- 

 bagh, is the site of a not very successful tea garden — the 

 requisite amount of moisture for the free growth of tea being 

 absent. 



In the extreme west there is a considerable thickness of sand- 

 stones resting on the Damuda Series, but the relations of these to 

 the Upper Panchets is still uncertain, probably they are some- 

 what younger. 



