Acanthophyllum tortum (TSIEN, 1969), Thamnophyllum germanicum SCRUTTON, 1968, T. occlusum (TSIEN, 1969) and T. tsieni n. sp. are described in detail and have been mainly collected at Pondrome, Wellin and Resteigne. The type specimens from several of these species as well as the holotype of Acanthophyllum vermiculare (GOLDFUSS, 1826) are refigured herein. Thamnophyllum germanicum has been found at the top of the Jemelle Formation. T. tsieni and T. occlusum also occur at the top of this lithostratigraphic unit, but are particularly abundant in the Hanonet Formation: moreover, T. occlusum is still present at the base of the Trois-Fontaines Formation. Acanthophyllum tortum is characteristic of the Hanonet Formation, but has also been observed in the X Formation and in the begin of the Trois-Fontaines Formation. Finally, the new geological surveys near Wellin confirm the lateral changeover from the base of the Trois-Fontaines Formation to the Hanonet Formation.