FollowingtheunanimousrecommendationoftheInternationalCommissiononStratigraphy,theGlobalboundaryStratotypeSectionandPoint(GSSP)forthebaseoftheCenomanianStageisdefinedatalevel36metresbelowthetopoftheMarnesBleuesFormation,alevelthatcorrespondstothethefirstappearanceoftheplanktonicforaminiferanRotaliporaglobotruncanoidesSigal,1948,onthesouthsideofMontRisou,eastofRosans,Haute-Alpes,France,whereitcanbeplacedinthecontextofaseriesofsecondarymarkerlevelsbasedonnannofossils,planktonicforaminifera,ammonites,andanornateδ^13Ccurve.