Sequence of predominantly medium to dark greenish-grey, locally light grey or mottled red, silty, locally slightly calcareous claystones, with locally minor intercalated thin, fossiliferous limestones, siltstones, and rare nodular, calcitic or dolomitic anhydrite beds.
Predominantly terrestrial, lacustrine to restricted lagoonal, coastal-plain setting with intermittent brackish-water influence. Marine influence seems to have been most significant in the basal parts of the member.
Conformable contact with more sandy sediments of the Aerdenhout Member, or the unconformable contact with the Altena Group.
Conformably overlain by the sandy Bloemendaal Member in blocks Q01 and K15. Otherwise, the top is represented by the conformable contact with sandier sediments of the Santpoort Member. In Subhercynian/ Laramide-inverted basin structures an unconformable contact with the Chalk or Lower North Sea Group can be seen. Locally, the Neomiodon Claystone Member or Rijnland Group can unconformably overlie the Fourteens Claystone Member.
