Calciferous Sandstone

Calciferous Sandstone, the Scottish representative of the lower portion of the Lower Carboniferous rocks, being contemporaneous with the Tuedian and the lower portion of the Carboniferous Limestone of England. It is divided into two groups, the lower or Red Sandstone group, and the upper or Cement-stone group. The former passes downwards into Old Red Sandstone, and in Ayrshire contains Old Red Sandstone species of fish with intercalated limestone bands containing Carboniferous Limestone corals. It is succeeded by extensive sheets of volcanic rocks (porphyrites and tuffs), in places 1,500 feet thick, with plant-bearing shales, extending from Arran and Bute to the mouth of the Forth, and from the Campsie Fells to Berwick and Liddesdale. The Cement-stone group, in the basin of the Firth of Forth, contains excellent building sandstone, used in Edinburgh, cement-stone or clayey limestone, clay-ironstone, coal, and valuable bituminous shales. The Burdie-House limestone, made up of the minute "shells" of the ostracod crustacean Leperditia Okeni, var. Scoto-Burdigalensis, but containing abundant fish-remains, belongs to this series. It also contains many and varied masses of lava, chiefly basalt, felsite, and porphyrite, and several varieties of tuff.