178 Proceedings of the Asiatic Society. [No. 2, 
constituted the several rock-masses associated with Coal in this 
country. Subdivisions no doubt were introduced, but all were class- 
ed under the one great epoch — and all were unitedly set down as 
Jurassic or Oolitic. 
This view was ably argued by the Eeverend S. Hislop in several 
papers, some of which were published in the Journal of this Society, 
and others, .in the Journal of the Geological Society of London— 
and such was the received opinion up to the publication by the 
Geological Survey of India of some of its researches. In 1856 for 
the first time, this enormous thickness and strange assemblage of 
rocks was broken up into its proper component parts by the separa- 
tion of the Talcliir group, of the Bajmahal series and recently of 
the Panchet series : all marked successive steps in reducing to some 
system and order, the enormous thickness of these sedimentary 
rocks and in defining more and more accurately the limits of that 
group, with which alone good beds of coal appeared to occur — the 
Damuda ; until now, on the plainest and most convincing physical 
evidence alone, independently of organic remains, it had become 
necessary to subdivide into at least six distinct groups, many of 
which are separated by wide intervals, the whole series which up 
to this time had been considered one. 
These subdivisions, established solely by the officers of the. Survey, 
had since been to a great extent adopted by Mr. Hislop and others, 
but nevertheless, so far as any published data are available, they 
still seemed to maintain unshaken their opinion of the Jurassic 
age of the great series associated with coal or what the Geological 
Survey call the Damuda series. 
This question had naturally engaged Mr. Oldham’s attention from 
his earliest arrival in India, and he had recently in a paper published 
in the 2nd volume of the Memoirs of the Geological Survey of 
India, given a brief summary of the results of his investigations 
on the subject. In this paper he had endeavoured to shew that 
the whole weight of the evidence fairly considered, went to assign 
a much earlier date to these rocks than had been previously assigned 
to them. He had shewn that a group of beds, to which he had 
given the name of Bajmahal, was of the same age, or contained all 
the same fossils, as beds described in Cutch by Capt. Grant, as 
being unconformably covered by others containing in abundance 
