222 FOSSIL COAL PLANTS. 
THE SOUTH OR BOTTOM WALL. 
After removal of the coal, the slate floor presents a perfectly beautiful picture of plants 
and compressed trunks of large trees; mostly in a well preserved state. Until the face 
of this southern wall has become obscure by the coal, mud, and dirt which rapidly accu- 
mulates in these thoroughfares, under the operations of the miners, this exhibition is sin- 
gularly interesting; and furnishes abundant opportunities for the study of fossil botany. 
The coal vegetation, thus favourably presented, belongs, in a great measure, to the 
class Sigillaria, which plants are allied to the family of arborescent ferns. Of these 
Sigillaria, or tree ferns, we think we can, with some degree of probability, distinguish five 
or six distinct species. One other species, also, apparently a Sigillaria, is particularly 
abundant. Its bark, now carbonized, is at least one third of an inch in thickness. ‘This 
being removed, the inner surface resembles somewhat the Syringodendron organum of 
Sternberg, (Tab. xiii.) although this is not an uncommon character among the thick- 
barked varieties. Its longitudinal grooves or strie are rather irregular, but average half 
an inch in breadth. The outer bark is roughly marked with an obscure and coarse 
tissue, and exhibits no distinct cicatrices. 
Of the family of Syringodendron, which also has been classed with the Sigillaires, we 
have apparently one species: of the Lepidodendron of Sternberg, two species; of Stig- 
maria, one species. From the shales of the outcrop of the vein, we derive two or three 
species of Neuropteris; three of Pecopteris; two of Sphenopteris, and one of Calamites. 
This list is evidently incomplete; and it forms no part of my present undertaking to 
prepare more than a sketch of the subordinate class of fossil plants. 
Among all these, as we have already intimated, the family of Sigillaria is the most 
conspicuous, and occupies by far the largest space. These gigantic plants are all placed 
horizontally; that is to say, parallel to the stratification. They seem to have sustained 
no injury, except such as might accrue from being flattened under great pressure; while 
the soft clay or argillaceous matter in which they were immersed, has evidently tended 
to their preservation. These stems are of very large size, as is shown by the accom- 
panying drawing. ‘They cross each other in every direction, and form no inconsiderable 
part of the mass of clay or mud, on and in which they repose. Among the most re- 
markable and beautiful of these fossils, is a bifurcated species, whose stems and branches 
are uniformly bent, or curved. We think we recognise in this species the Stglaria 
elegans of M. Brongniart. These are somewhat abundant here, and we have met with 
still more splendid specimens of the same species,* in the imperfect coal and coal shales 
below the upper red shale. On account of the obscurity of the cicatrices in those before 
us, baffling specific discrimination, it may possibly be Sigillaria Knorrii, (‘Tab. 156,) 
which so nearly resembles it; but the probabilities seem to favour the Sigillaria elegans; 
the scaly markings of which are smaller and more closely approaching to our specimens. 
A further reason for this preference is, that the elegans is dichotomous, and we have no 
evidence that the Knorr is. 
* I speak here from memory, as these fine specimens were subsequently destroyed by fire. 
