Heterogeneous. Greyish brown to brown organic clay, massively or horizontally bedded, with local sand laminae. Local shells and shell debris, common wood and plant fragments. Subordinate greenish brown to black gyttja, peat, and silty or clayey very fine to medium sand.
Predominantly meandering fluvial (Scheldt), including channel (sand), abandoned channel (gyttja, local clayey peat, humic clay, fine sand), and floodplain (humic clay). Also, estuarine (clayey sand with peat layers) and lacustrine.
Typically sharp and partly erosive contact with organics (Basisveen Bed, Nieuwkoop Formation, clastic tidal deposits (Wormer and Walcheren Members, Naaldwijk Formation), periglacial sand and loam (Boxtel Formation), older Scheldt sand (Koewacht Formation) or coarse fluvial and estuarine Rhine sand (Waalre Formation). Locally diffuse transition where interfingering with the Nieuwkoop (Hollandveen Member) and Naaldwijk Formations.
Typically sharp and partly erosive contact with organics (Basisveen Bed, Nieuwkoop Formation, clastic tidal deposits (Wormer and Walcheren Members, Naaldwijk Formation), periglacial sand and loam (Boxtel Formation), older Scheldt sand (Koewacht Formation) or coarse fluvial and estuarine Rhine sand (Waalre Formation). Locally diffuse transition where interfingering with the Nieuwkoop (Hollandveen Member) and Naaldwijk Formations.
