Brown to black lignite, clayey, with local intercalations of sand or fine gravel (Neurath Sand Member), commonly leached and locally altered into silcrete (Nivelstein Sandstone). Locally, beds of rounded flint. The single Main Seam is split up laterally into three major coal seams, from bottom to top the Morken Seam, Frimmersdorf Seam and Garzweiler Seam.
Coastal lowland, including freshwater marsh and swamp (lignite), bay, lacustrine and lagoonal (detrital organics and clastics), and beach and littoral (mainly sand). Main shifts between wetland and clastic settings were influenced by marine ingressions and regressions.
Sharp contact with non-marine sand and clay, formed in the transition zone from water to land (German Köln Formation), with shallow-marine and coastal sand and clay (Veldhoven Formation), and with deltaic and shallow-marine glauconitic or leached sand (Kakert, Heksenberg and Vrijherenberg members, Breda Formation). Farther west, gradual or diffuse, conformable boundaries with partly intercalated shallow-marine glauconitic sand (Breda Formation).
Top of pure lignite may be marked by burrows of marine organisms. Sharp, unconformably contact with fluvial sand (Inden Formation), deltaic and shallow-marine glauconitic or leached sand (Kakert, Heksenberg and Vrijherenberg members, Breda Formation) or various younger units.