This map shows the sediments close to the surface (or sea bottom), down to a depth of about 5 meters. This map is based on existing maps of the former Rijks Geologische Dienst and, where necessary, supplemented by unpublished data. The sediments are classified according to the new lithostratigraphical legend used by TNO since 1997. This classification is based on lithological and seismological properties, and on stratigraphic position and origin. The age of the sediments is not taken into account in this classification.