|Premise||Definition extended after NAM and RGD (1980) . For the sake of purity the lithological affix has been changed from ’Shale’ to ’Claystone’.|
|Derivatio nominis||Named after the village of IJsselmonde, currently incorporated into Rotterdam.|
|Type section||Location map||See figure (pdf)|
|Depth||1216 to 1234 m|
|Length||18 m along hole|
|Reference||NAM and RGD (1980)|
|Definition||Thin interval of light- to dark-grey, silty to fine-grained sandy, often marly claystone with open-marine to lagoonal fauna and flora. Thin argillaceous sand beds are intercalated.|
|Upper Boundary||The upper boundary, with the IJsselmonde Sandstone Member of the Vlieland Sandstone Formation, is gradual, but placed at the base of the massive sandstone.|
|Lower Boundary||The lower boundary, with the fine-grained paralic (Rodenrijs Claystone Member) and fluvial deposits of the Nieuwerkerk Formation, is sharp.|
|Distribution||South-eastern West Netherlands basin, especially in the Rotterdam area. Towards the north and west (de Lier and Berkel oil fields) this member grades into a thick se-quence of Vlieland Claystone Formation over the Berkel Sandstone Member of the Vlieland Sandstone Formation.|
|Age||Mid-Barremian in age. Characteristic dinocysts recorded are: Pseudoceratium pelliferum, Gardodinium trabeculosum and Odontochitina operculata.|
|Depositional Setting||Palaeogeographical and palaeontological data, and facies association suggest marginal- to open-marine de-position, associated with a barrier-bar complex towards the basin-fringe (south and east, IJsselmonde Sandstone Member of the Vlieland Sandstone Formation).|
|Sequence Stratigraphy||Represents the Late Transgressive to Early Highstand systems tract of sequence LZB 3.4.|
|References||See References Upper Jurassic/ Lower Cretaceous|
Van Adrichem Boogaert, H.A. & Kouwe, W.F.P., 1993-1997. [Stratigraphic unit]. In: Stratigraphic Nomenclature of the Netherlands.
Retrieved [Datum] from [url].