46 ball: geology of aueunga and htjtar coal MELns. 



contents have determined their age as belonging to the Kamthi- 

 Raniganj groups. This lithological resemblance is even strikingly 

 apparent in the hand specimens placed side by side in th,e Museum. 

 But for the existence of representatives of the Raniganj and Panchet 

 groups in the Aurunga. field and the obvious identity of these highest 

 rocks with those in the Karanpura field, I should have been at first 

 inclined to regard these rocks as being identical with the Hingir rocks. 

 The reflection suggested is that either the Hingir rocks are separable 

 into two groups, or that they indicate a coalescence or blending of the 

 characteristics of two groups which in this area are separated by a 

 distiuct interval. The geological history of other countries furnishes us 

 with cases parallel to the latter. The fact indicates the difficulties 

 which will be experienced in relegating these often unfossiliferous rocks 

 which occur in the wide region to the west and south-west to their 

 proper positions in the geological sequence. 



Along this central line of distribution there can be little doubt that 



„, ,. „ , , , the general surface of the Mahadevas before beino- 



Elevation or top beds ° >=> 



of Mahadevas. denuded stood at a pretty continuous and equable 



level of rather more than 2,000 feet, i.e., at the same level as that of the 

 bounding plateaux. 



The correlation of certain sandstones which occur as caps on some 



of the hill tops and ridges in the neighbourhood of the fields, more 



particularly on those south of the Aurunga, has 

 Age of hill capping 



sandstones unascertain- not yet been finally accomplished, and it is to be 



ed 



regretted that there has as yet been no time for doing 



so. . Prima facie, it might justly be anticipated that, wherever in the 



vicinity of the coal fields sandstones occur at elevations of, and over 2,000 



feet, they would prove to belong to the Mahadeva series. But the result 



of examination hitherto has been to demonstrate that, while the 



Damudas are represented by widely-separated deposits which occur at 



various elevations% the Mahadevas are restricted within very narrow 



» e. ff. in the Daltonganj, Chope, Itkuri and Kaxharhaxi fields. 



( 46 ) 



