Late Turonian ammonites from Haute-Normandie, France

Abstract

Upper Turonian chalks of Haute-Normandie yield a distinctive ammonite fauna within the Subprionocyclus neptuni ammonite Zone and the Plesiocorys (Sternotaxis) plana echinoid Zone. Well-localised material all comes from the phosphatic fauna of the Senneville 2 Hardground that marks the boundary between the Formation de Senneville and the Életot Member of the succeeding Formation de Saint-Pierre-en-Port. The association is dominated by Lewesiceras mantelli Wright and Wright, 1951, accompanied by Mesopuzosia mobergi (de Grossouvre, 1894), Lewesiceras woodi Wright, 1979, Subprionocyclus hitchinensis (Billinghurst, 1927), Subprionocyclus branneri (Anderson, 1902), Subprionocyclus normalis (Anderson, 1958), Allocrioceras nodiger (F. Roemer, 1870), Allocrioceras billinghursti Klinger, 1976, Hyphantoceras reussianum (d’Orbigny, 1850), Sciponoceras bohemicum bohemicum (Fritsch, 1872), and Scaphites geinitzii d’Orbigny, 1850. The fauna represents the Hyphantoceras reussianum Event of authors, elements of which have been recognised on the north side of Tethys from Northern Ireland to the Mangyschlak Mountains of western Kazakstan, a distance of more than 3,500 kilometres.