Light-grey and red-brown marls, and is characterised by an upsection increase in carbonate content.
Middle- to outer-neritic marine setting, where fines and carbonates settled. Rare, thin sand layers were deposited during storms.
Sharp decrease in GR-log readings and an increase of resistivity and sonic velocity character. In halokinetically influenced settings this member can rest unconformably on the Altena Group or older sediments. The lower contact appears to be more or less conformable.
Base of the chalky limestones of the Chalk Group (or its equivalent basal greensands in the West Netherlands Basin), and this can be observed on wire-line logs as a pronounced decrease in GR-log response and increase in resistivity and sonic velocity readings. This boundary can become quite arbitrary in distal basinal settings. The upper contact appears to be more or less conformable.