NERBUDDA DISTRICT. 175 



devas ; and in the valley of the Johilla, a section exposed near the village 



iT . x - x , of Bowri, shows the bent beds of the lower Da- 



Also to that of the 



upper beds. mudas faulted against the syenite of the country, 



where the junction between these is overlaid horizontally by the upper 



Damuda beds ; indeed many places in the Johilla valley and also in 



that of the Mahanuddi, show very well this kind of unconformity 



between the lower Damudas and the fossiliferous shales of the upper 



Damudas. 



The occurrence of isolated patches of the crystalline rocks surrounded 



~ Ll . „ ... on all sides by the beds of the lower Damudas, 



Outliers of the crys- J ' 



tallme rocks. j ias no j. unfrequently been noticed in our dis- 



trict. Similar facts have been observed in Orissa, and have been differ- 

 ently accounted for by different observers. It has been supposed on the 



Two modes of explain- one hand > that the ^ were due to Equalities of the 

 ing their occurrence. surface of the crystalline rocks at the time of the 



deposition of the lower Damudas, that is, they may be the tops of the 

 highest parts of that surface, down to the level of which a recent denu- 

 dation has now worn away the beds which once covered them ; and on 

 the other hand, they have been accounted for by faults. In Central 

 India the latter case occurs very frequently ; and although, perhaps, not 

 all, still certainly most of the isolated patches of the crystalline rocks 

 are bounded by such faults. A case where the fault can actually be seen 

 in section occurs in the Mahanuddi river near Peherna village : and in 

 many places we are led to conclude that the boundary is really a faulted 

 one, by the rectilinear direction of the boundary of the patches themselves, 

 and by the fact that this direction is independent of the strike of the 

 crystalline rocks, being, on the contrary, parallel to the general direction 

 of the boundary of the sandstone and crystalline formations, itself a 

 fault. 



A probable case of the former supposition occurs in the Hirun in the 

 upper part of its course, near the village of Narrainpur. 



