Buntersandstein

Bunter-sandstein, the name, the first half of which is generally adopted, for the lowest of the three divisions of the Triassic formation of Germany, derived from the highly-coloured or variegated sandstones of which it mainly consists. It is sometimes 1,000 feet thick, and is divided into the Lower Bunter, or Gris des Vosges, fine reddish argillaceous sandstone, often micaceous and fissile, with layers of dolomite and pisolite (Rogenstein); the middle, or Voltzia-sandstones, coarse-grained sands and sandstones containing the cypress-like Voltzia-heterophylla, with layers of shale containing the bivalve crustacean Estheria minuta; and the upper, or Roth, red and green marls with gypsum, containing the pelecypod Myophoria costata. The Bunter is usually barren of fossils; but plants such as Voltzia, Albertia, and Equisetum arenaceum, have been found at Sulzbad, near Strasbourg, and footprints of Labyrinthodon at Hildburghansen in Saxony. First identified in England by Sedgwick in 1826, the Bunter with us varies from 1,000 to 2,000 feet in thickness, and falls into three divisions: Lower Mottled Sandstone, soft, bright red and variegated, much false-bedded, 650 feet thick at Bridgenorth, 400 feet in Cheshire, and 200 feet in South Staffordshire; the Pebble-beds, or Conglomerate, reddish-brown sandstones with quartzose pebbles, from 60 to 750 feet thick, to which the white sandstone of Nottingham belongs; and the Upper Mottled Sandstone, generally red or yellow, developed near Liverpool and Birmingham, and reaching a thickness of 700 feet in Delamere Forest. The Bunter series occupies much barren land, such as Cannock Chase and Sherwood Forest; but it contains lead and copper-ores at the former place, and is generally a water-bearing series. In France it is known as the Gris bigarri. In the Gondwana series of India are fresh-water beds (Karharbari) containing a Bunter flora; whilst the Werfen, or Groden sandstones and Guttenstein limestone of the eastern Alps, with Ceratites cassianus, etc., are the marine or open sea equivalent of the Roth or Upper Bunter of Germany. Like most Trias (q.v.), Bunter beds have generally originated in inland lakes to which the sea found occasional access.