Page:A Treatise on Geology, volume 1.djvu/220

In France and England the muschelkalk is absent. Rock salt and brine springs occur in England and France only in the Keuper series: in Germany both in this and in the muschelkalk. Gypsum usually accompanies the marls which yield salt, but is also of more extensive occurrence.

In England the most complete section is probably that furnished by the beautiful and fertile vale of Severn, where every bed between the lias and the Palæozoic rocks of the Malvern and Abberley hills is easily traceable, in a thickness of 400 to 500 yards. The lowest of these beds, trappoid conglomerate, is probably of Palæozoic age,—a representation of some part of the Permian system. The series in general terms stands thus,—

Upper red marls; 200 to 250 feet. Enclosing a thin layer of light-coloured sandstone, and many bands of white and greenish marl, with strings and masses of gypsum. The uppermost part of the group is white, or greenish. (No fossils.)

Keuper grits and shales; 20 ft. Sandstone and thin shales, with false bedding littoral characters. (A few plants, shells, and fish remains.)

Lower red marls; 400 to 500 feet. Enclosing sandstone near the base, and laminated sandstone near the top. (Calamites?)

Red sandstone and conglomerate; 200 to 400 feet. False bedding and other marls of cements and water conglomerates; irregularly mixed with sandstones, and thin marls, mostly red. (No fossils.)

Farther south, the lower sandstones nearly vanish (in Somersetshire), but the marls receive a peculiar (local) calcareous conglomerate (millstone), to which probably the reptiles of Durdham Down may be referred.

Farther north, the series is continued and very widely expanded the marly upper portions admitting rock salt in Worcestershire and Cheshire ^[1]: the sandy

1. Mr. Ormerod estimates the gypseous and saliferous marls of Cheshire at 700 feet, the water stone beds below 400 feet, and the subjacent Bunter 600—Geol. Proc., 1848.