4 Records of the Geological Survey of India. [vol. hi. 
carried out, but at the same time strictly limited to those areas where the probable existence 
of similar conditions may be fairly anticipated after proper examination. 
As stated in my last annual report Mr. Medlicott was, at the commencement of tbo 
year, engaged in the examination of the very important geological questions of the extent 
and stratjgraphical relations of the several series of sandstones, &c., associated with the coal 
in Bengal as compared with those in Central India. In pursuance of this object, he 
traversed the entire country between Hazaribagh and Palamow on the east and 
Jubbulpnr, on the west; and thence went southwards to Nagpore and Chanda. This ex¬ 
tended and general survey of the vast area occupied bv these rocks has brought into greater 
prominence and clearness, and has established the wider application of several of the views 
already enunciated by other officers of the Survey regarding the distribution and variation in 
character of the several sub-divisions of that great series of beds, in some members of which 
the coals of India chiefly occur, and which may, as a whole, and in a broad view of its fossil 
contents, be called the plant-bearing series. The vast extension and wonderful constancy in 
mineral character (combined with local peculiarities) of the Talchir rocks, which have always 
been treated of as the base of this great series, although forming in themselves a well 
marked and characteristic group, has been even more fully established than it previously 
had been. The dying out also in passing to the west of the distinctions so easily established 
in the eastern coal-fields, (Raniguuj, Jherria, &c.), where a three-fold sub-division of the 
true Damu.da or coal-hearing rocks is obvious—a fact already fully indicated by Mr. Hughes, 
as far as the Bengal fields are concerned—has been shown by Mr. Medlicott to be entirely 
supported by the character of the rocks in the more western fields. And, at the same time, the 
co-existent fact of the considerable increase in the development of the group which occurs at 
the top of the series (the Panehet group), seems equally established. The entire group of 
the formations or series which in the oast gives five well-marked sub-divisions (Talchir, 
Barakar, Ironstone shales , Itanigunj, and Panehet) becomes at only a short distance to the 
west only a three-fold series of the Talchir, the Barakar, and the Panehet. This was shown 
to bo the case in some of the Bengal fields, and the same fact is more fully insisted on by 
Mr. Medlicott with reference to the country lying further west. 
Although, so far as known, there seem good grounds for admitting this as giving the 
truest representation of the facts, it must at the same time he stated that the lithological 
character of each of these groups differ in the west and south from that of the typical rocks 
in the Banigunj field and Talchir field. Even so near to Raniguuj as the Palamow 
(or Daltongunj field.) Mr. Hughes has shown that the Barakar rocks present a lithological 
character intermediate as it were between the true Barakar and the Itanigunj beds. And 
further, in the Bokaro field, he has pointed out the transitional passage of the Itanigunj beds 
into the Panchets. 
With these facts, it would almost remain an open question, whether much of those upper 
beds, to wbicli we are now disposed to assign the general name Panehet, may not represent, 
in time, the upper groups of the more eastern fields (Banigunj beds, Ironstone shale). And 
the fossils contained would go to support this view. But the general mineral character very 
decidedly approximates more to that of the typical Panehet rocks, and throughout the entire- 
area extending over many thousand square miles with well exposed sections, the absence of 
any deposits of coal, which are so valuable and abundant in the upper groups of the Banigunj 
field, is an additional and strong reason why these rocks should be referred to the Panehet 
group rather than to the others. It might possibly solve the difficulty better in the first 
instance to establish an intermediate and distinct sub-division applicable only to a part of this 
upper group of socks in the west, hut this would perhaps only lead to greater difficulties, because 
this group must he localized, while all the facts point rather to a gradual passage of character 
over geographical areas, than to any definite sub-division. In any such large series, where the 
sub-divisions are not marked by material interruption, or change, of deposit, or by any long 
interval of time accompanied by the destruction of pre-existing beds, there is no possibility of 
(hawing any trenchant line of division, for such does not exist. And it can, therefore, he 
only on a balancing of evidence that any part is placed in correlation with one sub-division 
rather than with another. 
Mr. Medlicott has also brought forward additional proofs to show that, on 
the large scale, the present limits of these coal-measure fields coincide approximately with the 
original limits of deposition and are not the result of faulting, or even mainly of denudation. 
