Sequence of red-brown, silty, often anhydritic claystones with some sand- or siltstone stringers and thin beds, and with rock-salt intercalations in the centre of the basin. Bedding structures can be massive, laminated or rippled, locally with abundant cracks, fluidisation phenomena and/or evaporite nodules. Intercalated sandstone beds are frequently reddish, graded, cross-bedded, and may contain clay pebbles. Some sandstone beds are light-coloured, free of clay matrix, laminated or cross-bedded. (see e.g. Mijnlieff et al 2011, Appendix B, Figure B2d).
Mainly water-laid deposits, although indications of subaerial exposure have been encountered. Predominantly lacustrine and playa-lake settings in the centre of the basin. In the transition zone, sabkha deposits predominate, with intercalations of distal fluvial-plain and aeolian sandflat deposits.
Unconformably overlies the Limburg Group (or possibly locally the volcanics of the Lower Rotliegend Group), or conformably covers the sandstone-conglomerate sequence of the Slochteren Formation (see e.g. Mijnlieff et al 2011, Appendix B, Figure B2d).
Overlain by the black bituminous shales of the Coppershale Member of the Z1 (Werra) Formation.