Exploration drillings conducted by ANDRA at the Marcoule site (SE France) have shown that the targeted Gargasian marls paradoxically pinch out basinwards under the middle Rhône valley, probably due to emersion and erosion prior to the Vraconian (uppermost Albian) major transgression. The hiatus is “compensated” by the deposition of a very thick (more than 400 m) silty clay formation, named “couche silteuse de Marcoule”, Vraconian to lowermost Cenomanien in age, which is the major discovery at the site. The discovery clearly evidence that the geometry of the coastal wedge can no longer be described as a result of relative sea level fluctuations on a simple ramp. Four times during the Gargasian to Santonian intervall, the ramp brok out, due to more or less pronounced reactivation of a so-named middle Rhône valley swell. At these times, strong forced regressions basinwards paradoxically correlate with floodings or strongly aggadational (“transgressive”) trends in marsh or deltaic facies shorewards. These four major cycles are probably tectonic in origin because they start with the “mouvements duranciens” auct. (i.e. the earliest stages of the pyrenean orogeny), and because they ryhthm the progressive closure of the Vocontian Trough prior to the major ante-Campanian paleogeographic reorganization of the French peri-Alpine belt. The challenge now is to understand how so strong a differential subsidence pattern may occur in such a tectonic context