Acanthophyllum simplex (WAI rui-R, 1929), Grypophyllum denckmanni WEDEKIND, 1922 and Disphvllum semenoffi n. sp. are described in detail and have been mainly collected in the lower part of the Givetian Mont d'Haurs Formation, on the south side of the Dinant Synclinorium. They are associated with Argutastrea tenuiseptata COEN-AUBERT & LÜTTE, 1990, Sociophyllum isactis (FRECH, 1886) and S. Wedekindi COEN-AUBERT, 1999. Several of these taxa are also present in the same lithostratigraphic unit at Cour-sur-Heure as well as near the base of the Nevremont Formation at Gerpinnes and Aisemont. The holotypes of Acanthophyllum simplex and Grypophyllum denckmanni are revised and refigured whereas the relations of these two taxa with the synonymous species introduced by WALTHER (1929) and WEDEKIND (1925) are discussed.