The Quarterly journal of the Geological Society of London . bility are well illustrated by the circumstancesin which these trunks have been preserved. The detailed Section,p. 4, sufficiently illustrate the beds immediately succeeding, includingthe main coal. The shale roof of the latter, however, merits specialremark. It abounds in large prostrate trunks of Sigillaria andLepidodendron. One of the former has been traced for 30 feet inthe roof of the mine. Poacites, Asterophyllites, Ferns, and otherleaves also abound in it, and many of these, as well as the trunksof the prostrate trees, have att
The Quarterly journal of the Geological Society of London . bility are well illustrated by the circumstancesin which these trunks have been preserved. The detailed Section,p. 4, sufficiently illustrate the beds immediately succeeding, includingthe main coal. The shale roof of the latter, however, merits specialremark. It abounds in large prostrate trunks of Sigillaria andLepidodendron. One of the former has been traced for 30 feet inthe roof of the mine. Poacites, Asterophyllites, Ferns, and otherleaves also abound in it, and many of these, as well as the trunksof the prostrate trees, have attached Spirorbis. Shells of Modiolaalso occur, though rarely. In addition to all this, there are erectstumps, the Stigmaria-rootlets of which insinuate themselves likeworms within the bark of the fallen trunks buried in the same collection from this bed gives a fine picture of the flora of theseswamps of the Coal period. On the surface of a bed of clay, 8 feet above the main coal, stands Fig. 5.—Section from the upper part of Group XXIII. (p. 4).. 1. Shale and sandstone. Plants with Spirorbis attached ; Rain-marks ? 2. Sandstone and shale: 8 feet. Erect Calamites. f An erect coniferous ? tree, rooted on 3. Grey sandstone: 7 feet. i. the shale, passes up through 15 feet of 4. Grey shale: 4 feet. (_ the sandstones and shale. 5. Grey sandstone : 4 feet. 6. Grey shale: 6 inches. Prostrate and erect trees, with rootlets ; leaves; Modiola; and Spi- rorbis on the plants. 7. Main coal seam : 3 feet 6 inches. 8. Underclay with rootlets. 1853.] DAWSON COAL-MEASURES, NOVA SCOTIA. 27 another erect tree converted into hard shining coal, and reaching tothe height of 15 feet, through beds of sandstone and arenaceous shale(fig. 5). Its roots, which are in the state of coal, spread in an irregularmanner through the clay or soft shale, and its top appears to bebroken off abruptly. After sand and mud had collected aroundthis tree to the depth of 10 feet, and while its top projected above
Size: 1504px × 1662px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1840, booksubjectgeology, bookyear1845
