100 
THE GEOLOGIST. 
A LECTURE ON "COAL." 
By J. W. Salter, F.G.S. 
(Continued from page 68.) 
We finished last month with the fact that plant-remains were found 
in plenty both above and below the coal. I shall draw your attention 
first to the roof-shale — or clay over the coal — " over-clay" as it is often 
called : for in this the great majority of remains are preserved. 
In the roof- shale two kinds of plants are the most conspicuous — 
fern-leaves, and the diapered cylinders mentioned in our last. These 
are the prevailing fossils, though there are a great many besides. 
Looking first at the fern-leaves, which from their beautiful forms 
cannot fail to strike the observer's eye, one is surprised to notice the 
extremely perfect state in which they occur. Delicate fronds, spread 
out as for the sheets of an herbarium, with hardly a leaflet disturbed 
from its true place, crowd the roof-shales of nearly all coal-mines. 
Dr. Buckland sang the praises of this beau- 
tiful tracery, which covers the roof of the 
mine, in glowing strains such as it will 
not do for a plain geologist t.o imitate. I 
have a lurking suspicion, however, that the 
great doctor conceived the passage not in 
the mine, but oiit of it. 
At least one hundred and twenty species 
are known in our British coal-strata. So 
perfect are they occasionally, that the little 
fruit-patches (sori, as botanists term them), 
are found upon the backs of the fronds. This 
is not very common, except in one kind — 
the Pecopteris, which happens to be more 
abundant than most of the others, and in 
some species of this the fruit is found. 
There is a specimen in the Museum of 
Practical Geology which shows these little 
seed-patches. It is from the Forest of Dean ; 
and Mr. G. Roberts has shown me several, 
and given me some from the coal-field of 
Bewdley Forest. We shall give a figure of 
this fruit in our next number. 
Some ferns, nay, many of them remind 
us closely of the tree-ferns familiar in our 
hot-houses ; others resemble the humble 
Fig. 6.— Portion of a frond 
of Alethopteris (Pecopteris) lon- 
chitiex. — Brong. 
* Those who really wish to know more about coal-plants than this little sketch 
will give them, should read the article on coal in the new edition of Mantell's 
" Wondsrs of Geology." By T. Rupert Jones, Esq., of the Geol. Society. 
