CHAPTER VIL 



Upper Gondwana. 



Lulrajjmr Group (Mahadeva series.) 



On a first examination of any of the ordinary sections in which 

 the sub-tr'appe'an rocks are exposed in the Rajmehal hills, the impression 

 conveyed to the mind is that they all belong- to but two series, namely, 

 the Talchir and the Damuda. It is not until the greater portion of the 

 area has been visited, and some of the cases of excessive overlap have 

 been examined, and the upper rocks traced from the gneiss upon which 

 they rest back into the valleys where their junctions with the true 

 Damuda rocks are exposed, that the fact of the existence of representa- 

 tives of a third series discloses itself. 



Further and more'detailed examination proves the existence of local 



instances of denudation and unconformity, though, 

 Unconformity. 



as a general rule, a perfect parallelism appears to 



exist between the topmost beds of the Damuda and the bottom of the 



upper series. In addition, as will be shewn presently, the evidence afforded 



by the fossils suggest and justify the separation. From these fossils it 



was at one time considered that these rocks should be regarded as being 



a lower member of the intertrappean group, and the name of Dub- 



rajpur, one of the principal localities where they are exposed, was 



given to the group. This name is retained as above. The reasons which 



seem to justify the relegation of this group to the Mahadeva series'* 



*This term is now in provisional use to indicate a great, but as yet undetailed, thick- 

 ness of Upper Gondwana rocks in the Satpuras ,• as the term Damuda series has long been 

 used to represent a"great portion of the Lower Gondwana deposits in Bengal. Neither term 

 is likely to become general, as the sub-divisions of the whole system vary much in different 

 areas, e. g., in the Godavari reign the most marked physical break in the whole section occurs 

 in the middle of the "Damuda series :" and, strictly speaking, the llajmehal group is 

 within the "Mahadeva series," as being older than the Jabalpur group, which caps that 

 series in the Satpuras. 



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