Zur Gliederung mittel- und jungpleistozäner Schichten in der Niederrheinischen Bucht

Abstract. From the waterworks of Bensberg east of Cologne and a gravel-pit near Efferen west of Cologne, there have been described layers of clay and fine-sand, containing fossils with humus layers from a depth of about 16 to 18, 20 meters below the surface of the Lower Middle-Terrace of the Rhine (i.e.: about 58 m above sea-level). These sediments enable us to separate stratigraphically in the sand-gravel-sequences the overlying from the underlying stratum one. Heavy mineral analysis shows, that the underlying series belongs to the Middle Middle-Terrace of the Rhine (of Late-Mindel-age). The distribution of this terrace within the Lower-Rhine-Basin thus cannot be limited only to some narrow channels („Channel-Gravel"), but is supposed to be developped over the whole breadth of the valley, like in the Middle-Rhine-Valley, yet here buried under sediments of the Lower Middle-Terrace. The palynologic investigation of the humus layers within the clay and flnesand-layers of the waterworks of Bensberg shows a flora indicating a late-interglacial age by their high percentage of Abies-Alnus-Picea-values. According to the stratigraphical findings they can only be attached to the Mindel/Riß-interglacial Krefeld-Beds. The investigations carried out led to a critical examination of the existing attempts of difTeren-ciating the Middle-Pleistocene beds in the Lower-Rhine Basin. The Kempen and Neuwerk Beds have to be separated from the Krefeld Beds, according to both the stratigraphic and the floristic and faunistic findings, and must be attached to the Gerdau-Interstadial, the first one probably belonging to a late and the latter (much more probably) to a middle part of this Drenthe/Warthe-Interstadial. The authors try to give a climatic-chronologic table of all Middle Pleistocene beds in the Lower-Rhine-Basin.