234 Proceedings of the Royal Physical Society. 
species founded on imperfectly preserved material,—the 
types of which in the great majority of cases are lost, and of 
which, even with the figures that accompany their descrip- 
tion, there is not sufficient data to enable one to recognise 
again the plants which have been intended.! 
The addition of such doubtful species to the lists would 
not give any further insight into the Carboniferous flora, 
and would only hamper the subject with barren names. 
Although I have taken every means in my power to accu- 
rately ascertain the horizons from which the fossils came, mis- 
takes may have crept in, as the evidence has been collected 
from so many sources; but in all cases where I saw any reason- 
able cause for doubt, no record has been made of the species. 
Neither do I claim infallibility in my identifications, 
though I have taken every care to obtain accuracy in this 
respect; still, when one considers the many thousands of 
specimens which must have passed under my examination, 
it is quite possible that some slips may have occurred. But 
even admitting this, I feel confident that there are no errors 
which in any way vitiate the general conclusions arrived at 
as to the value of fossil plants in distinguishing the different 
series of the Carboniferous formation which are accepted in 
this address. 
It is not my intention to enter into the question of the 
affinities of the plants with which we have been dealing. 
The subject is too large a one to go fully into at present, 
but before concluding, I wish to make a few short remarks 
on this subject. 
I am afraid that we must give up several of our old ideas 
of the ancestry of some of the existing genera. 
One used to be taught that the humble club-mosses which 
grow on our hills and moors, and the horsetails (Zquisetum) 
that garnish our lochs. and river shallows, were the de- 
pauperised descendants of the Lepidodendra and Calamites 
respectively. 
I am sorry to say that my faith in this beautiful ancestral 
pedigree has been rudely shaken, and I am, further, afraid 
1 See list of some of these, Proc. Roy. Phys. Soc., vol. x.,-1891, p. 390. 
It is possible, however, that some of these may yet be identified. 
