The Permian Formation. (Wond. p. 533). The separation of the strata now termed Permian from the Triassic, with which they were formerly classed, was first proposed by Sir Roderick Murchison, and is based on the fact that the fossils hitherto discovered are entirely distinct from any that occur in the Trias and subsequent formations; it is, therefore, inferred, that after the deposition of the so-called Permian strata, a complete change took place in the faunas and floras of the lands and seas, and the Trias is at present regarded as the dawn of a new system of organic beings.
The strata comprised in this group are variegated blue and red marls and sandstones, like those of the Triassic; magnesian or dolomitic limestones; and conglomerates more or less coloured with peroxide of iron.
Subdivisions:—
| 1. | Red and white marls. |
| 2. | Yellow magnesian limestones, and dolomitic conglomerates of Yorkshire and Durham. |
| 3. | Marl-slate in thin layers, containing reptiles and fishes. The Keuper schiefer or copper-schist of Mansfeld. |
| 4. | Marls and variegated sandstones, sands, and clays. |
Obs.—This group includes the Lower Bunter, Zechstein, and Rothliegendes[21] of the German geologists. The Permian comprises all the deposits that intervene between the Triassic above, and the Carboniferous below; and it is believed that this formation contains but one type of animal and vegetable life.
[21] Signifying Red-dead-layer; it is a German mining term denoting that the copper of the upper bed has died out; this layer not being metalliferous.
The Carboniferous, or Coal Formation. (Wond. pp. 660-748). Sandstones, grits, shales, layers of ironstone, and clay, with immense beds of coal; fresh-water limestones sparingly; marine limestones abundantly.
Subdivisions:—