| Summary: | Following the unanimous recommendation of the International Commission on Stratigraply, the Global boundary Stratotype Section and Point (GSSP) for the base of the Cenomanian Stage is defined at a level 36 metres below, the top of the Marnes Bleues Formation, a level that corresponds to the the first appearance of the planktonic foraminiferan Rotalipora globotruncanoides Sigal, 1948, air the south side of Mont Risou, east of Rosans, Haute-Alpes, France, where it can be placed in the context of a series of secondary marker levels based on nannofossils, planktonic foraminifera, ammonites, and an ornate δ13C curve.
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