The Albian–Cenomanian boundary coincides with a positive stable carbon isotope excursion that previously has been correlated with an oceanic anoxic event (OAE1d); however, there are other secular isotopic excursions associated with the Albian–Cenomanian boundary as well as the Early Cenomanian that are preceded by OAE1d. The focus of this study is Deep Sea Drilling Project (DSDP) Hole 547A (eastern North Atlantic), where multiple isotopic excursions spanning the Albian–Cenomanian boundary and Early Cenomanian have been correlated to the Albian– Cenomanian boundary event (ACBE) and Lower Cenomanian events (LCEs) I to III of the Mont Risou (France), the English Chalk, and...