The complex system of subterranean passages at Montesquieu-Avantès in the foothills of the central French Pyrenees through which the River Volp flows is conventionally divided into three caves, Le Tuc d'Audoubert to the west, Les Trois-Frères in the centre and Enlène to the east. While the east two are connected by a narrow corridor, no usable passage connects Tuc d'Audoubert with Trois-Frères and the only current means of access is by boat. At Tuc d'Audoubert the galleries lie on three levels, the lowest carrying the River Volp, the ‘median’ with decorated galleries (La Salle Nuptiale, La Galerie des Gravures) and the upper with further decoration (La Chatière, Salle des Talons) terminating in the Salle des Bisons containing the celebrated modelled clay bison (Bégouën and Clottes 1984b). The position of Trois-Frères and Enlène approximates to the upper level of Tuc d'Audoubert. Trois-Frères has numerous galleries with several possible original entrances, although the only certain Magdalenian access was through Enlène. Whereas Trois-Frères contains one of the most prolific arrays of wall art (Galerie des Mains, Chapelle de la Lionne, Galerie des Points, Salle du Grand-Eboulis, Sanctuaire, Galerie des Chouettes, Galerie de l'Hémione), Enlène has none. However excavations at Enlène have revealed a considerable range of engraved bones and stone plaquettes from occupation deposits (Bégouën and Clottes 1984a).