[Footnote 147: "Description of an upright Lepidodendron with Stigmaria-roots in the roof of the Sydney Main Coal, in the Island of Cape Breton. By Richard Brown, Esq."--_Geological Journal_, No. 13, for June, 1847, p. 46.] The main bed of coal is six feet in thickness, and is overlaid, as usual, by a roof of shale abounding in foliage and fragments of branches. As the coal is dug out, large masses of the shale fall in, and occasionally hollow spaces, called by the workmen _pot-holes_, are left in the roof; the fallen masses being the roots and truncated stems of Sigillariæ and other trees, which separate at the parting formed by the coaly bark covering the roots, when the supporting coal is removed. The following sketch represents one of the specimens of the base of a stem of a Lepidodendron, with the roots (_stigmariæ_) attached. This figure (1) shows the position of the tree above the bed of main coal, with the inclination and length of two of the principal roots, so far as they could be distinctly traced; and the following sketch (2) represents the trunk, with its branching roots, constructed from careful measurements of the dimensions and position of each root, drawn on the spot. The stem at the part marked A, was encrusted with a coaly bark, covered by the usual cicatrices of the Lepidodendra, and the roots at B, C, D, with a similar carbonaceous investment, impressed with the characteristic pits or areolæ of Stigmariæ. [Illustration: _Fig. 1._ STEM OF LEPIDODENDRON WITH ROOTS.] [Illustration: _Fig. 2._] In the Instance of the upright stems of Sigillariæ in the same coal-field, the roots were also unequivocally Stigmariæ. Fig. 3, represents one of these erect stems, sixteen Inches high and twelve inches in diameter at the top, which dropped from the roof of the bed after the coal had been removed. Part of the coaly bark remains at _c_. The decorticated part of the trunk is covered with minute scales as far as the point _h_, a few inches below the first ramification of the roots. The carbonaceous crust investing the roots was thick at the upper part, but gradually became thin, and at _a_, and _b_, was a mere friable pellicle, that fell off upon the slightest touch. [Illustration: _Fig. 3._ STEM OF SIGILLARIA ALTERNANS, 1/12 _natural size_.] [Illustration: _Fig. 4._]