The so-called Hengelo Basin, a depression formed by inland-ice during the penultimate glacial (Saalian) has, for the greater part, been filled by deposits dated to the last glacial (Weichselian). These deposits, mainly clay alternating with sandy and organic layers, are exposed in the Rientjes pit near Hengelo. A molar of woolly mammoth Mammuthus primigenius was found in the pit. The molar most probably originated from a cryoturbated, organic layer, with an absolute age of 43.030 ± 1680 – 1390 BP. Younger deposits (37.500 ± 650 BP) dated to the Hengelo Interstadial yielded, together with floral remains such as leaves of arctic willows ( Salix reticulata, Salix herbacea, Salix polaris), mountain avens (Dryas octopetala) and the dwarfbirch (Betula nana), two rather complete lemming skeletons: a skeleton of the arctic lemming Dicrostonyx torquatus, and remains of the Norway lemming Lemmus lemmus. The skeletons are almost complete indicating that we are probably dealing with lemmings which died in burrows in which they lived during winter as protection against the cold and against predation.