sandstones which form their roofs, we find erect stumps of sigillaria and other trees, showing that the accumulation of the coal terminated as it had begun, by a forest-growth. I introduce here a section of a few of the numerous beds of coal exposed in the cliffs of the South Joggins, in Nova Scotia, in illustration of these facts. We can thus see how in the slowly subsiding areas of the coal-swamps successive beds of coal were accumulated, alternating with beds of sandstone and shale (Figs. 41, 42). For other details of this kind I must refer to papers mentioned in the sequel. [Illustration: Fig. 40.--Vegetable tissues from coal. _a_, _Sigillaria_ and _Cordaites_. _Calamodendron_.] Returning to the more special subject of this work, I may remark that the lepidodendroid trees and the ferns, both the arborescent and herbaceous kinds, are even more richly represented in the Carboniferous than in the preceding Erian, I must, however, content myself with merely introducing a few representatives of some of the more common kinds, in an appended note, and here give a figure of a well-known Lower Carboniferous lepidodendron, with its various forms of leaf-bases, and its foliage and fruit (Fig. 43), and a similar illustration of an allied generic form, that known as _Lepidophloios_[CB] (Fig. 44). [CB] For full descriptions of these, see "Acadian Geology." [Illustration: Fig. 41.--Beds associated with the main coal (S. Joggins, Nova Scotia). 1, Shale and sandstone--plants with _Spirorbis_ attached; rain-marks (?). (2, Sandstone and shale, eight feet--erect _Calamites_; 3, Gray sandstone, seven feet; 4, Gray shale, four feet--an erect coniferous (?) tree, rooted on the shale, passes up through fifteen feet of the sandstones and shale.) 5, Gray sandstone, four feet. 6, Gray shale, six inches--prostrate and erect trees, with rootlets, leaves, _Naiadites_, and _Spirorbis_ on the plants. 7, Main coal-seam, five feet of coal in two seams. 8, Underclay, with rootlets.]