In the sandpit called ”De Fransche Kamp”, situated on the ice-pushed ridge east of the Gelderse Vallei, there is an outcrop of Pleistocene sediments. One of the clay layers contains mammal fossils and molluscs. The preliminary results of the study on the mammal fossils are represented in this paper. The fauna indicates the deposition of the clay in a period with a warm-temperate climate and in a mainly wooded environment. The fauna is correlated with the Maastricht-Belvedere fauna 4 and because of this correlation is supposed to have a Saalian age. For the time being this fauna is dated as an interglacial stage which may best be correlated with the ’warm’ Hoogeveen interstadial.