Etude des couches de passage Couvinien-Givetien entre la vallée de l'Ourthe et la vallée de l'Aisne

This paper deals mainly with the sections in the Aisne Valley, at Rouge-Minière and Sy. A small section at Filot completes that of Sy. Certain observation could also be made in the Pont-le-Prêtre stream section, near Villers-Sainte-Gertrude and at Ferrières. These sections have allowed a better appreciation of the important variations in facies which occur near the Couvinian-Givetian boundary. This boundary has been delimited more exactly on the basis of ostracods, conodonts and corals.