. The geological history of plants. Paleobotany; 1888. Fia. 40.—^Vegetable tissues from coal, o, SigiUaria and Gordaitet. b, Calamodendron. table debris of all kinds, including sometimes vast quan- tities of lepidodendroid spores, and the microscopic study of the coal gives similar results (Fig. 40). Further, on the surfaces of many coals, and penetrating the shales or sandstones which form their roofs, we find erect stumps of sigillaria and other trees, showing that the accumula- tion of the coal terminated as it had begun, by a forest- growth. I introduce here a section of a few of the nu- m
. The geological history of plants. Paleobotany; 1888. Fia. 40.—^Vegetable tissues from coal, o, SigiUaria and Gordaitet. b, Calamodendron. table debris of all kinds, including sometimes vast quan- tities of lepidodendroid spores, and the microscopic study of the coal gives similar results (Fig. 40). Further, on the surfaces of many coals, and penetrating the shales or sandstones which form their roofs, we find erect stumps of sigillaria and other trees, showing that the accumula- tion of the coal terminated as it had begun, by a forest- growth. I introduce here a section of a few of the nu- merous 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. 12. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Dawson, John William, Sir, 1820-1899. New York, D. Appleton and Company
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