PART 2 .] 
Ball: Blsrampur Coal-field. 
27 
Upper sandstones. 
Extent of T&lcMrs. 
total exclusion of the other rocks which go to make up the Barakar group in the eastern 
coal-fields renders it impossible to identify individual beds in sections at any distance from 
one another. And the coal seams are far too irregular and variable in thickness to be of 
much use for this purpose. 
From the general horizontality of the beds, from the character of the basin in which 
they lie, and the outcropping of the Talchirs on all sides, it is evident that, as compared with 
the eastern fields, the thickness must be inconsiderable, and I find it difficult to bring myself 
to believe that it anywhere amounts to even as much as 500 feet. 
With the upper sandstones it is less difficult to assign a definite thickness, though it 
be a minimum one. The horizontal beds which form the Pilka 
hill are about 1,000 feet thick. 
II.—Talchirs. 
The natural geological boundaries of the Bisramptir coal measures include an area suffi¬ 
ciently limited and compact for convenient description; but such 
is not the case with respect to the underlying Talchirs. Were 
the usual practice—one very well suited to the Talchirs underlying the coal measures of the 
eastern basins—of following out the rocks to their extremest limits adopted in Western 
Chota Nagpur, we should find ourselves obliged to follow the extension in one direction 
towards Eitva and Mirzapur, and in the opposite some 100 miles or so towards Sambalpur. 
As it has been found with the metamorphic rocks elsewhere, so the Talchirs, which 
spread over such an enormous area in Sirguja, can be most satisfactorily discussed in a 
general account of the district, apart from their relations to any particular basin occupied by 
coal measures. 
In describing the distinct areas of coal measures which occur in Western Chota Nagpur, 
I propose in future to adopt artificial boundaries, which will include a limited margin of 
the surrounding rocks. 
In the present instance the Rehr river serves as a very convenient boundary, except for 
Limits of Talchirs here a short distance near Paharbulla, where the coal measures them- 
deseribed. selves cross it. 
On the north of the field, outside the fault which bounds the coal measures, there are 
two patches of Talchirs. The principal of these situated west 
of the village of Kiunra, is of an irregular triangular shape, and 
is traversed by the Mahan river. The rocks in the lower portion of this area adjoining 
the fault are pebble and boulder beds, with some hard sandstone: the latter I did 
not at first recognise as belonging to the Talchir formation, but further on it is seen to pass 
into true Talchirs, which extend up the Sukaia river for about a mile. A short distance 
north-east of Sugri these rocks are cut off by a ridge of slaty quartzites. In the upper 
reaches of the stream just mentioned, outside our limits, there is a strip of Talchirs the 
boundaries of which have not yet been mapped. 
The second patch of Talchirs lies south of the village of Maliaispur; it is of quadran¬ 
gular shape, and is in area about If square miles. Its northern 
boundary is very irregular, a stream which runs with it alternately 
exposes Talchirs and metamorphics. 
From the position of the faulted boundary, which is well seen in the Banki river close 
by, there can be little doubt that these patches lie outside the run of the fault, but I did 
not succeed in finding any point where the section showed direct opposition ol the edges 
of the Barakars and Talchirs. 
TSlchlrs west of KiunrS. 
TAlchlrs south of MaMispur. 
