358 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. .Mar. 21,
bifurcate twice in the quarter i, m, which is the only complete por-
tion of the fossil. If the ramifications in the other three quarters
were as regular as in i, 9n, which I have every reason to suppose
was the case, having found a similar arrangement in two other trees
of the same species, we should have thirty-two roots within a circle of
eighteen inches diameter.
There are four large tap roots in each quarter of the stump, as shown
in fig. 7, and about five inches beyond these a set of smaller tap roots
striking perpendicularly downwards from the horizontal roots, making
forty-eight in all, viz. sixteen in the inner and thirty- two in the outer
set ; and, what is a still more remarkable feature in this singular
fossil, there are exactly thirty-two double rows of leaf-scars on the
circumference of the trunk. This curious correspondence in the
numbers of the roots and vertical rows of leaf-scars, surely cannot be
accidental. I am not aware that any similar correspondence has ever
been observed either in recent or fossil plants. The inner set of tap
roots vary from two to two and a half inches in length ; the diameter
at their junction with the base of the trunk being about two inches,
as shown in fig. 8, which is one-half the natural size. The outer set
are much smaller, being about one inch in diameter at their junction
with the horizontal roots, and from one to one and a half inch in
length. Very few of either set are strictly conical, although they
probably were originally of that shape ; some are squeezed into an
elliptical, others into a triangular form ; all have been wrinkled hori-
zontally, as shown in fig. 8, by the shrinkage due to vertical compres-
sion. A thick tuft of broad flattened
rootlets radiates from the termina- -'^ig* °*
tions of the tap roots, and a few in-
distinct areolae are \^sible on their
sides ; the length of these rootlets
does not appear to exceed three or
four inches, their width being one-
fourth of an inch ; a raised black line
runs down the middle of each, similar
to that observed in the rootlets of
Stigmariae. These short thick tap
roots were evidently adapted only to
a soft wet soil, such as we may easily conceive was the nature of
the first layer of mud deposited upon a bed of peat, which had
settled down slightly below the level of the water.
We may infer also, from the existence of a layer of shale without
fossil plants, immediately over the coal, that the prostrate stems and
leaves which occur in such large quantities in the next superincum-
bent bed, fell from trees growing upon the spot, and were entombed
in layers of mud held in suspension in water, which at short intervals
inundated the low marshy ground on which they grew ; for had the
plants been drifted from a distance, we should find them in the first
layer of shale as well as in those higher up.
Although the main coal is generally overlaid by shale, yet occasion-