2.2.1. St-Joseph Formation - STJ
Authors: Bultynck & Godefroid, 1974; Bultynck, 1991a.
Description: The most striking characteristics are the light-greyish shelly and crinoidal limestones, occasionally silty, intercalated in a chiefly grey-greenish silty shaly succession. The macrofauna is essentially composed of brachiopods.
Stratotype: Nismes, hamlet St-Joseph, local road to Regniésart.
Hypostratotype: Olloy-sur-Viroin, cut along path 200m south-west of the village church.
Area: Southern and south-eastern flank of the Dinant-Synclinorium up to Hotton-Hampteau; from Villers-Ste-Gertrude on the St-Joseph Fm and the overlaying Eau noire Fm cannot be clearly separated.
Thickness: About 40m between Couvin and Olloy-sur-Viroin, 160m in the Wellin-Halma area, about 50m at Grupont and 30m near Marche.
Age: Latest Emsian; conodonts from the St-Joseph Fm belong to the patulus Zone (Bultynck & Godefroid, 1974).
Remarks: The St-Joseph Fm corresponds to Formation 2 described by Bultynck & Godefroid (1974). The St-Joseph Fm constitutes the lowest part of the Couvinian, formerly used as lower stage of the Middle Devonian in the Ardenne.