COUNTRY NORTH OF THE SON AND WEST, ETC. 1 47 



hand, exposures are bad, a good deal of the country lying under cul- 

 tivation or the rocks being otherwise so ill-exposed or concealed as to 

 render minute examination of the ground difficult or impossible ; and 

 on the other hand, the sub-zones themselves do not seem to retain for 

 any distance their individual characters owing to rapid lateral 

 change. So the attempt to map these sub-zones was given up, the 

 whole of the beds being classed as one main zone and mapped as such. 

 Although the shales and thin*bedded sandstones constituting the 



Zone I exhibit lithological variations from 

 Zone I persistent. 



place to place, they seem on the whole to be 



persistent over the entire area, though they may be lying a good deal 



concealed in some localities, as on the east, or found to have lost 



much of their thickness, as seen towards the west. 



Zone //.—Limestone with shales. 



The shales are argillaceous, well-laminated, 



Character of the beds. • 



greenish, non-calcareous and free from ripple- 

 marks. 



The limestone in its look and color is not often unlike that of 

 Zone V, but is altogether much purer. 



Beginning on the west, this zone is well seen at the confluence of 

 the Andhiari Nadi with the Mahanadi River (Lat. 



The zone as traced from o/xtt o o / t- \ it 



junction of the And- 24 5 N., Long. 8 1 2 L.). Here a considerable 



hiari eastwards. .• - . . . . 



quantity or the green shales occurs associated 

 with the limestone. The band is well traceable from here, with a 

 strike east by north, along the Son and occupying most of the river-bed 

 for a distance of about 10 miles, after which it leaves the Son and 

 runs almost due north-east along the southern foot of the sandstone 

 scarp one mile north west of Deora. By Deora the zone has very little 

 shale in it, beds of limestone making up almost the entire thick- 

 ness. After crossing the Nagour Nadi the lime- 



The limestone dies out _ 



by Ucheyra. stone band begins rapidly to lose in thickness and 



to die out by " Ucheyra" of map. From this point eastwards as far 

 as the neighbourhood of Ghungta no limestone is visible in this horizon 

 (a good deal of the intermediate country, it must be remembered, 



L2 ( 847 ) 



