PART 3.] 
Oldham: Geology of the Central Provinces. 
71 
area these rooks both ‘ Upper and ‘ Lower’ are much crushed and contorted, hut they are 
only locally (in the south-west) penetrated by igneous rocks, probably of' the same period as 
those of the great basaltic area. The extensive plains of Bilaspur and Raipur are formed 
on rocks very similar in composition, arrangement, and external relations to those of the 
Lower Vindhyan formation as seen to the north, and these extend from here along the upper 
courses of the Mahanadf into very close proximity, if not actual continuity, with the 
similar deposits in the Chanda and Sironcha districts, and beyond the limits of the 
Central Provinces to the south, extend at intervals into the Madras Presidency, where they 
cover an immense area in the Kaddapa and Karnul districts. Our knowledge of these 
detached areas is not as yet sufficient to justify an assertion that they were once continuous, 
although the striking identity in lithological character of the several deposits lends strong 
support to this view. Throughout all these widely-extended deposits there is constant 
physical evidence of their having beeu accumulated in comparatively shallow water, and so 
far under physical conditions favourable to life. The sandstones are false-bedded and beauti¬ 
fully rippled on their surfaces, each successive bed, often for hundreds of feet in thickness, 
showing its own ripple-marked surface. Nor is there anything in their mineralised condition 
to suggest the chance of subsequent obliteration of organic remains, had they ever been 
imbedded or become fossilised. Yet no success has hitherto rewarded our most careful 
searchings for such traces of early existences, 
Coal-bearing rocks. 
Passing upwards in the historical succession of rocks, we find in India a wide gap in the 
geological record between the Vindhyan rocks, just 
alluded to and the next succeeding series of deposits, 
in which are included the coal-bearing rocks. The whole face of the country wherever these 
occur must have been entirely remodelled by long-continued denudation and other causes 
before the commencement of the deposit of this great plant-bearing series of beds. This 
series has attracted much attention, both from its economic importance, and from the fact 
that it is in all its groups more or less fossiliferous. And the proper sub-division of it as 
represented at distant localities has been the subject of much study. Nor has the detailed 
examination of the country yet been sufficiently extended to admit of a final decision of this 
question. 
Three great groups have, however, been thoroughly established—the Tdlehir, the 
Damudd, and the Panchet rocks, and representa¬ 
tives of these three great groups have been found 
wherever the general series occurs. It is solely as to the exact limits of each that any 
question still exists, which can only be answered after more detailed examination. This 
question is, however, of high practical importance, because of the three series which I have 
mentioned only one is proved to contain workable beds of coal. The Tdlehir rocks below 
contain no coal, and the Panchet rocks above are equally without any coals, the whole of the 
workable beds of coal of this geological epoch being found confined to the Damudd rocks. 
Sub-divisions. 
The largest area occupied by the rocks of this great series within the Central Provinces 
. , . ,, lies in the hilly region to the south of Iloshanga- 
Satpura coal-fields. J f 1 
bad aud Narsinghpiir, partly within the bound¬ 
aries of these districts, but principally belonging to Cbhindwara, and embracing the Pach- 
marhi or Mahadeo hills. At the base of the series we find the characteristic deposits of 
the Tdlehir group—greenish silt beds, breaking up into small splintery flakes and sharp 
fragments, and hence called ‘needle shales,’ and greenish brown or whitish earthy felspathic 
sandstones, in either of which pebbles and large boulders are often irregularly scattered. 
Often these are very numerous and form a distinct bed, to which, from its peculiar constitu¬ 
tion, the name of “ Boulder” Bed has been given. These rocks, generally speaking, are 
