Five close collective neolithic tombs have been discovered during the development of a gravel quarry of the lower valley of the Seine river, in the Vaudreuil meander (« Boucle du Vaudreuil »). This article purpose is to present briefly these buildings which haven't all yet been completely excavated, insisting on the different aspects of the problems which can be tackled nowadays in the case of salvaging excavations. Original leads of research are, for instance, the study of the connections between the buildings, or their « history » , which means their impact on the surrounding site and on the human occupation after their use for the funerary layers.