The geophysical prospecting on a medieval dwelling site in the Limousin region defined by a combination of an artificial cavity and surface structures, in addition to the classic objectives of detecting buried remains, provides complementary information to the dig. It provides a description of the link between local geology and the site's implantation (apparent resistivity) and the extension of the dwelling zone around the main entrance to the underground cavern (apparent magnetic susceptibility). By measuring the magnetic susceptibility of the materials encountered in the stratigraphy of the ground, a definition of the layers responsible for the anomalies is made possible. Finally, this information, together with the archaeological results, contributes to the analysis of the function of pits. -- AATA