The Chanxhe and Rivage sections along the Ourthe River are two important reference sections for the Devonian/Carboniferous (D/C) boundary in the northeastern part of the Dinant Basin. Seven major microfacies types are defined in the D/C strata (50 m) of these two sections. They permit recognition of several levels encompassing the Comblain-au-Pont and Hastière formations. These levels record shallow open-marine sedimentation oscillating between the storm and the fair-weather wave bases in the euphotic zone. The microfacies in the upper part of the sections (Hastière Formation) indicates strong salinity variations with evaporitic reflux and lagoonal influences. The environment is again open-marine in the uppermost part of the Hastière Formation. The general environment consists of small shoals which have partly isolated an offshore domain (MF1-MF4) from a semirestricted area (MF6 and MF7) where salinity fluctuations were the predominant factor as indicated by monospecific fauna and flora ( Earlandia , umbellinids, calcispheres, .). Only ostracods and Earlandia minima (foraminifers) survived in these stressful environments. These organisms are related to cryptalgal bindstones or mats located at proximity and forming numerous "algal chips". The abundance of sulfate pseudomorphs in MF5, MF6 and MF7 indicate the importance of the diagenetic reflux of evaporitic brines in this general shallow marine environment. The main diagenetic overprint is the development of clear sparite cements replacing the original textures.The foraminiferal zonation indicates hiatuses throughout the series. Ostracods are moderately abundant in the Chanxhe and Rivage sections and sixty-two taxa, the majority of which are in open nomenclature, are recognized; nearly all are illustrated, and one new species ( Cavellina chanxhensis nov. sp. ) is established. They belong to the Eifelian Mega-Assemblage and practically all samples containing identifiable ostracods contain podocopid ostracods indicative of well-oxygenated water conditions with ...