L'Hettangien dans le NE du bassin de Paris: Biostratigraphie et evolution sedimentaire

The Ammonite-fauna allows to follow the evolution in time and space of the Luxembourg-sandstone-formation in the North-East of the Paris Basin. The biostratigraphic subdivision is specified for the whole Hettangian. The occurrence of Mesogean elements belonging to the genus Waehneroceras and Discamphiceras among a fauna with boreal features leads to some paleogeographic considerations. The presence of early Schlotheimiidae in the lower Hettangian raises a phylogenetic remark.