It has been proposed to introduce archaeological data for the constitution of a general data bank containing urban information and the geological data of the subsoil. This data bank is to be established by the Delegation Générale à la Recherche Scientifique et Technique as a project for the use of architects, urbanists and others concerned by land organization and utilization. It is hoped that better preservation for well known but still unexcavated remains will result from this project. The first data was obtained from a survey in the experimental area of Dunkerque; the basis of this data bank and its use are described here.