We investigated the Quaternary lithological succession and faunas in a borehote near Moriaanshoofd (Province of Zeeland, SW Netherlands), Ín order to improve our understanding of the depositional context of classical Gelasian mammal faunas from the region. The fossils mostly derive from the base of a fossil-rich interval between 31 m and 36.5 m below the surface, that was initially interpreted as a Middle or Late Pleistocene interglacial marine unit, but turned out to be a Late Quaternary fluvial unit with large amounts of reworked fossils and sediments. Eocene mollusc taxa pinpoint Ftanders (Belgium) as the source region for this river. Within the base of this paleo-Schelde River fossil material of various stratigraphic provenance became incorporated.

We describe the occurrence in the Netherlands of three teeth of Mimomys hajnackensis (Arvicolidae, Rodentia) from three separate boreholes extending into marine deposits of the Maassluis Formation. These marine Pliocene/Early Pleistocene deposits at depth are overlain by, and interdigitate eastwards with, the freshwater deposits of the Waalre and Peize Formations (formerly known in part as the Tegelen Formation).Teeth identified as M. hajnackensis have not previously been described from the Netherlands although similar material has been reported from Pliocene deposits in Germany at Frechen and Hambach close to the Dutch border. The material described here comes from boreholes at the Polder de Biesbosch near Dordrecht, Diepenveen and Deventer. To our knowledge, these finds represent the oldest described rodent fossils from the Netherlands, corresponding to an absolute age of 2.9 to 3.3 Ma on the basis of comparison with other European localities, implying that the remains are reworked from older deposits.

We investigated fossil small mammals from a borehole near Moriaanshoofd (Zeeland, southwest Netherlands) in order to get better insights in the fossil mammal faunas that are found in the subsurface in the southwestern Netherlands, and to investigate the age and provenance of the mammal fauna that is being dredged from the deep tidal gullies in the nearby Oosterschelde estuary. The record in the borehole covers Gelasian (Early Pleistocene) to Holocene deposits, represented by six formations. Thirty-nine specimens of small mammals were obtained from the borehole. These fossils derived from the Early Pleistocene marine Maassluis Formation and from directly overlying deposits of a Late Pleistocene age. During Weichselian times (33-24 ka), a proto-Schelde River shaped the northern Oosterschelde area. The river reworked substantial amounts of Early and Middle Pleistocene deposits. At the base of the Schelde-derived fluvial sequence (regionally described as the Koewacht Formation), Gelasian vertebrate faunas were concentrated in the channel lag. The Late Pleistocene channel lag is almost certainly the main source for the rich Early Pleistocene vertebrate faunas with larger mammals dredged from the Oosterschelde.