A field study carried out in 1996 on the northern border of the Aquitaine Basin, had as subject the Middle Cenomanian Rudist carbonate episode. The Oleron Island rocky strand flat (Charente-Maritime) extends over more than a square kilometre, it is at this reduced scale that the main features of a paleogeographical distribution model have been identified. In fact, simultaneously a vertical rhythmic succession of environments, fast lateral variations of facies and original geometrics of sedimentary bodies are brought into evidence. The abundance of gathered data calls into question the value of the Madame island section as a reference section for the Middle Cenomanian. The field observations at Oleron allow the recognition of four Rudist environments to replace their development in the context of sequence stratigraphy and to suggest a new paleogeographical model for the Middle Cenomanian of the Charente area. The favourable location of the Oleron strand zone allows the observation of the effects of minor tectonic readjustments of the Armorican basement which occasionally guide the sedimentation during the Middle Cenomanian.