GENERAL GEOLOGY Or THE AKKA. 



1,3 



north and south of the actual basin indicate their probable former extent. 



Startino- from Tatapani, we find a natural contact of Gondwanas resting 



on metamorphic schist along the eastern and north-eastern boundaries 



of the field. From near Gumharia a nearly east to west fault,^ indi- 



_ , . ^, cated bv fault-rock and much crumpling- of the 



Boundaries mostly •' x o 



faulted. strata, extends along the whole northern boundary, 



defining an angle in it near the boundary of the K-ewah State, where 

 we find a high escarpment of Mahadeva sandstone abutting against the 

 metamorphics. From there the boundary is again natural, and we find 

 Talchirs resting on the gneiss. 



From Tatapani eastwards we see the coal-field cut off on the south 

 Few natural bounda- ^J ^ S^'^^^ f^^^*^ throwing the several beds of 

 ries. Gondwanas successively against crystalline rocks. 



Here and there the fault has traversed the latter and left natural bound- 

 aries with the Gondwanas, exposing the Talchirs as lowest beds, which 

 probably covered the floor of the basin over the entire surface. Such a 

 natural boundary we find along the exposure of Talchirs west of Kandia, 

 between Bhagwanpur and Dandkarua, and along the exposure in the 

 Mahan-Rer nullahs ; the section through all the rocks of the Gondwanas 

 near Namadhaka (about five miles south-by-west of Dandkarua) I fancy 

 is brought about by denudation only, as there can be little doubt that 

 the line of contact with the granite is faulted. 



Roughly speaking, the Gondwana area examined forms a narrow 



f t t f ^^^ (from twelve to about thirty miles wide) of sedi- 



Gondwanas. mentary rocks in the metamorphics, preserved from 



denudation only by their having subsided between lines of nearly parallel 



faults. The remaining portions of Gondwanas left at higher levels, 



resting on metamorphics, have been removed by 



denudation, though isolated patches of them are 



still found, here and there, outside the area of the field, thus clearly 



indicating the former extent of the basin. 



( 141 ) 



