64 
Records of the Geological Survey of Indie. 
[vol xx. 
those described from a well known and defined horizon amongst the rock-systems of Europe, 
while not one of the animal fossils, which serve to determine the age of the lower portion of 
the Australian coal strata, has ever been found in our series. 
I regret only that the provisional determinations of the plant remains given by Mr. 
Oldham in his paper in the Memoir’s, vol. II, have been misunderstood, and have given 
rise to wrong conclusions, as the present state of our knowledge shows that the real 
relations of the fossil plants arc different from what they were formerly supposed to be. 
For any safe inference the following conditions must he fulfilled :— 
1. —Only a thorough determination of the fossil remains can he used for the 
determination of the age of the series. 
2. —The comparison must be made with all the known floras, and not only with 
one, especially if that one be not typical. 
3. —Where, besides the fossil plant remains, there are no fossil animals, the typical 
plants must determine the age of the groups, especially if the species of 
plants are identical with other well known and characteristic forms found 
in formations of well determined age. 
4. —The conclusions must agree with all laws of Palaeontology; if one law is aban¬ 
doned, the conclusions are uncertain, and contradictions appear which are 
unnatural. 
5. —It is not unnatural that certain genera having a wide range in time should 
be common to several series. They can, however, be of no important 
influence in fixing age, which must be determined by the other fossils 
with which they are associated. 
For instance,"there is nothing strange in the same species of Ptilophyllum, Morr., 
occurring both in the Rajmalial series ( Lias ) and in the Kach series (lower Oolit e), 
nor in some species of Ferns or Pquisetaceie, being found in the Carboniferous 
and Permian; "and similarly there is no reason why a certain species of the genus 
Glossopteris, Brgt., occurring in our Da mil da series, the flora of which is really 
Mesozoic, should not also be found as well (and perhaps prevail) in some of the supposed 
Palaeozoic coal strata of New South Wales. 
We shall see fhat’characteristic species are found in the Panchet group and throughout 
the Damuda formation, and that these species clearly define the age of the beds, while 
Schizoneura is common to both, and proves that both belong to the same great epoch. The 
Damuda group has no real connection with the lower coal-beds of New South Wales, 
although Glossopteris, Brgt., occurs iu both, and in Australia (but only in the lower strata) 
is associated with marine fossils of palaeozoic age. The plant-beds of Kach and those of 
I’ajmahal, as was shown in the last number of the Records, arc, it is true, of different ages, 
but yet belong to the same great epoch, and are related by the occurrence of certain species 
of the genus Ptilophyllum, Morr.; in the same manner* wo shall find that the three series 
now to be described are also connected together by common forms: that the Panchet 
('■roup is connected by a species of Schizoneura with the Damuda, and these latter again 
with the Talchirs by Gangamopteris; proving that all these three, though of different age, 
belon 0- to tho same epoch. There may be, and of course are, other opinions about the age of 
these groups. I can only remark, that as long as no other proofs are found, the fossils 
alone can serve to decide the geological age, agreeing, as they do, with other well known 
species from well defined series; and as these are all well known fossil .plants, these must 
decide. 
