Ceratites and Terebratula . Osmoregulatory pressures limited to organisms. Both dolomites and evaporites extend up into the Keuper before red mudrocks and fine sandstones complete the succession. There are no prolific fossils suitable for correlation and stratigraphic sequences are established on the basis of lithological variations in successions no more than 300m thick. The Alpine facies begins with red beds, but is mainly of marine sediments, commonly several km thick.
Fossils are abundant, so chronostratigraphic correlation is possible.
Although the sediments are thick they are generally shallow marine deposits, not deep sea successions. There are none of the hypersdaline deposits typical of the Muschelkalk seas, but in the east reefal limestones develop on blocks surrounded by muddy deeper water sediments. The basal Triassic sediments sit on a late Permian surface which was dominated by a major river system draining SW-NE from the north of the Massif Central, through the Trier area and the Eifel towards Poland and beyond into Russia. In the Permian and early Trias it was low enough for occasional shallow influxes of the Tethyan sea, which proceeded to dry out in a series of desiccation cycles. Around this sea the uplands were undergoing destruction by the rivers which carried sands into the low ground, generally producing successions of red fluvial sandstones and red mudstones.