Transactions of the Royal Society of Edinburgh . en inthe form of three or four inches of a black pyritous shale (E), and next by the inroad of a large quantity of dark sandy mudand drift vegetation, which has been preserved as asandy shale (F), containing Catamites, Producti, ganoidscales, and other traces of the life of the time. Finally,a great sheet of lava, represented by the uppermostamygdaloid (G), overspread the area, and sealed upthese records of Palaeozoic history.* A final example may be cited of the regular alter-nation of lavas and tuffs with each other, and withordinary sedimenta
Transactions of the Royal Society of Edinburgh . en inthe form of three or four inches of a black pyritous shale (E), and next by the inroad of a large quantity of dark sandy mudand drift vegetation, which has been preserved as asandy shale (F), containing Catamites, Producti, ganoidscales, and other traces of the life of the time. Finally,a great sheet of lava, represented by the uppermostamygdaloid (G), overspread the area, and sealed upthese records of Palaeozoic history.* A final example may be cited of the regular alter-nation of lavas and tuffs with each other, and withordinary sedimentary accumulations. The well-knownCalton Hill of Edinburgh consists of the successionof rocks shown in the subjoined section (fig. 24). Thegreat mass of the hill is made up of beds of porphyrite,representing true superficial lava-currents (Nos. 1,5, 7, 9, 11, 13, 15). With these are intercalated bandsof nodular tuff, and occasional seams of shale and sandstone, more or lesscharged with volcanic detritus (Nos. 2, 4, 6, 6, 8, 10, 12, 14). The whole. ^ <%k^^~^^ Fig. 23.—Section in WardlawQuarry, Linlithgowshire.
Size: 1272px × 1963px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorroyalsocietyofedinbur, bookcentury1800, bookdecade1880
