82 
Records of the Geological Quroeg of India. 
[vol. is. 
four are identical with European forms found either in the Tithonian beds of Southern 
Europe, or the Portland Oolite of England and Prance, and he adds that this proportion of 
forms common to the two regions will increase greatly when the other classes of mollusca 
are described, ‘ as many of the Pelecgpoda of this bed seem to bo identical with species from 
the Portland stone,’ and elsewhere he especially mentions the abundance of Trigonice ol the 
type of T. gibbosa. 
This is not written with a view of impugning Dr. Feistmantel’s conclusions. These will 
be given to the public in full in the ‘ Palteontologia Iudica,’ and 1 have no doubt are as accurate 
and trustworthy as Dr. Waagen’s. But it is important to call attention to the exact terms 
of the contradiction between the marine and terrestrial forms of the Kachh Oolites, because 
it shows that one or the other is misleading when applied to the determination of geological 
age. As the marine fossils are much more numerous, and probably allord a much less im¬ 
perfect representation of the life of the period, as they occur in a larger sequence of rocks 
and have attracted much more attention, and as they are preserved in a manner which, I 
believe, it is generally considered, enables their affinities to be determined with greater 
accuracy, it will, I think, be admitted by most paheontologists that we must accept the con¬ 
clusions derived from them. The deduction is inevitable, that the comparison of the remains 
of plants leads in this case to results, as regards geological age, which are not accurate, and 
that other identiticatious on similar data must be received with great caution. 
It necessarily follows that although the homotaxis of the Ra j medial flora he liassic, 
and that of the Panehets and Damudas triassic, we can only accept this homotaxis as an 
approximation to the actual geological age of the formations. 
Between the Upper Gondwana rocks to which the Rajmehdls and Jabalpurs belong, 
and the Lower Gondwana series comprising the Pancbets, Damudas, and Takhirs, there is a 
great break in the forms of life. Cycads abound in the former, but have not hitherto been 
found in the latter, whilst the lower series is characterized by the abundance of equisetaceons 
plants. The only genera known to be common to the t wo, are ferns of considerable range in 
time. It follows as a matter of course that no arguments as to the age of the Lower 
Gondwana rocks can be drawn from the upper part of the series. 
The evidence which Dr. Feistmantel has shown to exist in favour of ascribing a Triassic 
age to the Paucliets, Damudas, and Takhirs is undoubtedly of great importance; but I feel 
some doubts as to whether it is conclusive, and although it is with great hesitation that 
I venture to express a different opinion on a subject on which Dr. Feistmantel’s knowledge 
of palseobotany enables him to form a more accurate opinion than I can offer, I still think 
that if the evidence of plants alone be employed to determine the age of the Indian rocks, 
the relations between the Indian and Australian coal-measures must be taken into consi¬ 
deration in estimating the bomotaxis of the Indian formations.* 
It is also only fair to point out that the main arguments for the triassic age of the 
Damudas are derived from the occurrence of three plants which were only discovered this 
year. Even admitting, for the sake of argument, that the evidence at present justifies 
the reference of the Dannida beds to the Trias, it by no means follows that the flora known 
sixteen years, or even two years ago, was sufficient to warrant the same conclusion, and 
I believe Dr. Oldham was quite right in 1860,t and that my brother, Mr. H. F. Blanford, 
was equally justified^ in 1874, in assigning a palaeozoic age to the Dannida formation on the 
evidence of the plant remains alone. The Pauchet beds have always, since they were first 
defined, been considered as probably Triassic. 
* I>r. teistmautel a argument, that because the marine forms which determine the age of the Australian reeks 
arc absent in India, the evidence ol the plant remains becomes of less value, is quite true, but it is just us applicable 
to the Darnuda plants eommou to the trias of Europe as to those found also iu Australia. 
t Mem. Geol. Suit, of India, II, p. 333, &c. 
J Quart. Joum. Geol. Sot'., 1S75, pp. 628, 531, &e. 
