430 Correspondence—Rev. W. Downes. 
T have neither seen nor heard of any other sclerotic plates having 
been obtained from British Carboniferous strata, and shall be glad 
to know if any collector of British Coal-measure fossils has obtained 
specimens from any British colliery or coal strata. 
26, ARcHBOLD TERRACE, T. P.. Barxas, FEG:s: 
Newcastie-on-Tynez, July 17, 1880. 
FOSSILS ON TRANSVERSE CLEAVAGE PLANES. 
Srr,— Will you kindly accord me a little of your space to give 
publicity to certain observations which I have made upon the above 
subject ? 
The possibility of fossils occurring upon cleavage planes, when - 
those planes do not happen to be coincident with the bedding, first 
occurred to me as a question in connexion with investigations made 
by me somewhat more than a year ago in the Culm-measure Lime- 
stones of Westleigh, in Devonshire. A (?) fossil seemed to occur on 
a (?) cleavage plane. This I showed to several competent judges, 
to whose opinions I should usually, and with good reason, readily 
yield. But in this instance opinions were conflicting. First, by 
some I was told that it was a fossil, and that therefore the plane on 
which it occurred was a bedding plane, not cleavage. Next, by 
others I was told that the plane was certainly a cleavage plane, and 
(ergo) that the supposed fossil was no fossil. 
This set me considering whether there could be no via media in 
the matter. And I found, when I began to make inquiries, that 
better geologists than myself had observed similar phenomena, and 
confessed themselves to be perplexed by them. 
I do not lay any great stress upon the Westleigh specimen. I 
confess myself to be very doubtful now about its organic origin, 
though at one time I held a different view. It, however, led me to 
make inquiries elsewhere, and through the kindness of Mr. H. B. 
Woodward, Mr. Kinahan, and Mr. W. Hughes of the Victoria Slate 
Quarries, Carrick-on-Suir, Ireland, I was furnished with specimens 
which were perfectly convincing as to the fact, account for it how 
we may. 
The first specimens sent to me by Mr. Hughes from these Lower 
Silurian rocks showed Graptolites and Fucoids upon what he affirmed 
to be cleavage planes, but, not feeling quite satisfied about the 
matter, 1 wrote to him again, asking for details of the structure of 
the rocks, and pointing out, by means of drawings, that the cleavage 
which in one place was inclined at a high angle to the bedding 
might elsewhere, through the folding of the beds, become coincident 
with the bedding. 
To this he replied by sending me a specimen in which both 
bedding and cleavage were shown. The former was shown by 
colour streaks, and upon the latter, inclined to the bedding about 80°, 
was a Fucoid impression. He says: “In no part (of the quarry) are 
the bedding and the cleavage coincident. We find the fossils occurring 
on the cleavage in different parts of the quarries, whatever position 
the latter may hold with regard to the bedding.” He added also 
