Research and report by the Flemish Planning Bureau on the Environment and Spatial Development (VPO), on the construction of a reference database of the Flemish subsurface. The data was collected by analyzing samples from the subsurface sample repository (Geotheek) of the Department of Environment and Spatial Development. A large number of qualitative samples were taken of a large number of different geological units. The collected data contain information on grain size, glauconite content and (in)organic carbon content. This report is updated periodically.