234 SEWARD: A NEW BRITISH CARBONIFEROUS FOSSIL. 
which, in some places, a careful examination reveals the existence of 
closely arranged, small and indistinct depressions ; these appear in 
the figure as small dots immediately above the spiral ridges. If the 
fossil be viewed from either end, or if the spiral lines be carefully 
followed, it will be seen that there are two spirally wound bands, 
which appear on the surface as broad shallow grooves and projecting 
ridges. The form of the cast is more or less cigar-shaped, and 
tapering towards either end; the more pointed and perfect end is 
shown at x; the other end is less perfect, and evidently broken. 
In section, the fossil has the form of a flattened ellipse, probably the 
result of compression. This peculiar cast was found in a mould 
have been formed by some thin projecting structure which was 
attached in two spiral lines to the surface of the fossil, and became 
embedded in the surrounding sand. 
We may conclude, then, that in Fig. 1 we have a somewhat 
imperfect sandstone cast of the internal cavity of the original 
structure, and in Fig. 2 the impression, in a sandstone mould, 0 
the surface markings of the fossilised body. The organic substance 
itself, which originally existed between the cast and mould, has 
entirely disappeared. The body must have been hollow and provided 
with a strong resistant wall, which was able to withstand the pressure 
the surrounding sand, thus enabling an internal cast to 
formed without more than a partial compression of the whole 
structure. One notable fact to be observed is the absence of 
carbonaceous matter between the cast and mould. The absence of 
such coaly substance, although by no means as some have suggested, 
in itself a fatal objection to the vegetable nature of the fossil, should 
make us recognise the possibility that we have to deal with some 
animal and not plant organism. Before speaking of the possible 
Naturalist, 
