editorial reviewed ; The gravel that covers the sub-flat surfaces above 180 m a.s.l. around Liège are the subject of a sedimentological study, in relation to the state of knowledge in terms of Oligocene stratigraphy taking into account the uplift/tilting of the NW flank of the Ardenne. General as well as field and laboratory data are set out in the preceding article published in the same volume of the Journal. This leads to a new model of morpho-sedimentary evolution of the hydrographic network linked to an indeterminate Oligocene marine regression in a sub-coastal environment. Two successive routes of the Ourthe through the Hesbaye (north of Liège) join the regression oligocene coast northwards. The first terrace of the Meuse upstream of Liège attests a flow also directed towards that shore. The entry into the scene of the Meuse downstream from Liège and therefore in the Netherlands requires captures in order to successively divert the Vesdre, the Ourthe and then only the Meuse. The validity of the earlier models which connect the Traînée mosane s.l. to terraces in Dutch Limburg is therefore disputed.