below, grey, red and green marls, with gypsum and dolomite—this is the gypskeuper in its restricted sense. The higher part of the series is sandy, hence called the Steinmergel; it is comparatively free from gypsum. To this division belong the Myophoria beds (M. Raibliana) with galena in places; the Estheria beds (E. laxilesta); the Schelfsandstein, used as a building-stone; the Lehrherg and Berg-gyps beds; Semionotus beds (S. Bergen) with building-stone of Coburg; and the Burgand Stubensandstein. Kohlenkeuper, Unterkeuper or Lettenkohle, the lower The lower division consists mainly of grey clays and schieferletten with white, grey and brightly colored sandstone and dolomitic limestone. The salt, which is associated with gypsum, is exploited in south Germany at Dreuze, Pettoncourt, as well as in Vie in the Lorraine region of France. A 4-metre (13 ft) coal is found on this horizon in the Erzgebirge on the border between Germany and the Czech Republic, and another, 2 metres thick (7 ft), has been mined in Upper Silesia, now in Poland. Great Britain In Great Britain the 'Keuper' is no longer a formally recognised geological division. The one-time Keuper Marls are now redesignated as the Mercia Mudstone Group. The underlying Keuper Sandstone is now the Helsby Sandstone Formation at the top of the Sherwood Sandstone Group. Traditionally it contained the following subdivisions: Rhaetic or Penarth Grey, red and green marls, black shales, and so-called white (). Upper Keuper marl, red and grey marls and shales with rock salt, . As in Germany, there are one or more bone beds in the English Rhaetic with a similar assemblage of fossils. Lower Keuper Sandstone, marls and thin sandstones at the top, red and white sandstones (including the so-called waterstones) below, with breccias and conglomerates at the base, . Basal conglomerate A shore or scree breccia derived from local materials; it is well developed in the Mendip district. The rocksalt beds vary from 25 cm (1 inch) to in thickness; they are extensively worked (mined and pumped) in Cheshire, Middlesbrough and Antrim. The Keuper covers a large area in the Midlands and around the flanks of the Pennine range; it reaches southward to the east Devon coast, northeastward into Yorkshire and northwestward into Northern Ireland and southernmost Scotland. Fossils The Keuper is not rich in fossils; the principal plants are cypresslike conifers (Walchia, Voltzia) and a few calamites with such forms as Equisetum arenaceum and Pterophyllum jaegeri. Avicula