COEEESPONDENCE. 
303 
ther more likely tliat the shales represent iuterraediate and different 
conditions happening between each formation of coal ; and, in this 
case, the ferns imbedded in the shales may have belonged to quite 
another class of vegetation from that which formed the coal. Has 
anybody ever thought sufficiently how far the tender herbs of those 
days and myriads of fallen seeds might have been the chief sources 
of that bituminous product which makes England the first country 
in the world for civilization and wealth ? 
It is not our intention now to enter, however, into the matter of 
the formation of coal, nor of the nature and characters of the many 
beautiful vegetable forms which are imbedded in the intercalating 
strata. But we wish some one would earnestly take up the work. 
COEEESPONDENCE. 
The Older Farian in Trinidad. 
Deae Sie, — Permit me to observe, in reply to Mr. Lankester (whose 
letter appeared ia your issue of July), that I am not the authority for the 
correlation of the Older Parian formation in South America and Trinidad, 
with the Neoeomian of Europe. Indeed, from the references I gave 
I sliould have thought that ]\Ir. Lankester would have had no great diffi- 
culty in finding out that the supposed age of the formation in question 
rested upon far better evidence than any I could produce. I had it only 
in my power to add a little to the evidence already accumulated on tho 
subject, and to demonstrate it almost to a certainty that the rocks at 
Pointe-a-Pierre in Trinidad do belong to the same formation which it was 
the opinion of the Government Geological Survey that they did ; that is, 
to the formation at Cumana, containing Trigonia suhcremilata. The opinion 
of the Government geologists was built upon evidence which was none the 
worse for being strengthened ; and I had it in my power to do so. 
But if the references given in the footnotes to my paper are not suffi- 
cient, I beg to refer Mr. Lankester to those appended to Mr. AYall's paper 
on the geology of Venezuela and Trinidad (Quart. Journ. Geol. Soc, 
vol. xvi. p. 465). Von Buch's work on the fossils collected by Humboldt 
contains much evidence relating to the age of the formation in South 
America. 
When I transmitted my paper to you I was perfectly aware of Professor 
Huxley's views as regards " homotaxis ; " and I have held opinions of 
a somewhat similar kind for some time previously to reading Professor 
Huxley's able address to the Geological Society. But in writing my 
paper on the Older Parian formation, my object was not to support or 
elucidate any theory which is yet quite new and unacknowledged by 
geologists at large ; more especially when it did not make the least difier- 
ence one way or the other as to the question upon which I was engaged. 
Whether the rocks in South America containing organic remains of types 
