The Quarterly journal of the Geological Society of London . e left, a slight mark nearer the left side appears to indicate a tail(fig. 18, MS.). Group XXVII. is a dense series of underclays and their accom-paniments, including eleven terrestrial or soil surfaces, five thin coals,erect plants at four levels, and two bituminous limestones. It muchresembles some of the groups at the commencement of the section,and like some of these is very pyritous, marking the action of sea-water to a greater degree than in those central parts of the measureswhere Modiolce and their accompaniments are less plen
The Quarterly journal of the Geological Society of London . e left, a slight mark nearer the left side appears to indicate a tail(fig. 18, MS.). Group XXVII. is a dense series of underclays and their accom-paniments, including eleven terrestrial or soil surfaces, five thin coals,erect plants at four levels, and two bituminous limestones. It muchresembles some of the groups at the commencement of the section,and like some of these is very pyritous, marking the action of sea-water to a greater degree than in those central parts of the measureswhere Modiolce and their accompaniments are less plentiful. Themost remarkable part of this group is that represented in fig. includes a bed of erect Catamites and an erect tree with distinctStigmaria-roots (fig. 12, ms.). The underclays are here so crowded 1853.] DAWSON — COAL-MEASURES, NOVA SCOTIA. 29 above the erect plants, that the rootlets of one underclay pass downwardamong the erect Calamites, and the rootlets of another pass beside Fig. 8.—Section from the lower part of Group XXVII. (p. 3).. 7 65 1. Shale. 2. Shaly coal: 1 foot. 3. Underclay with rootlets : lft. 2 in. 4. Grey sandstone passing downwards into shale: 3 ft. Erect tree with Stigmaria roots (e), on the coal. 5. Coal: 1 inch. 6. Underclay with roots : 10 inches. 7. Grey sandstone: 1 ft. 5 in. Stigmaria rootlets continued from the bed above; erect Cala-mites. 8. Grey shale, with pyrites. Flattened plants. and within the cast of the erect tree, and have helped to obliterateits surface-markings, by passing downward immediately within thebark. The roots of this tree are casts in sandstone, probably fromthe surface of the sand surrounding its upper part, but the stumpitself is filled with shaly clay from the underclay above. It willbe observed that one of the bituminous limestones in this grouphas been converted into a Stigmaria-underclay and supports anerect tree. In Group XXVIII. and the remainder of the section, we findgradually decreasing evidences of g
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Keywords: ., bookcentury1800, bookdecade1840, booksubjectgeology, bookyear1845
