On the initiative of the Archaeological Service of the Fribourg canton (Switzerland, in charge: D. Ramseyer) an International Meeting was held at Marigny (Chalain Lake France) on the 29th and 30th of September 1994, in cooperation with the Direction of Conservation of Museums of Jura Region (France, in charge: M.- J. Lambert). The topic of the meeting was: Archaeology and Erosion. Protective Measures for the Preservation of Lakeside, Settlements. The organizers’ objective was to facilitate the contact between specialists, in conservation on the one hand and in preserving sites of ecologic and archaeological significance on the other. In this meeting the first of its kind in Europe, expert scientists were participating who had taken protective measures for stemming lake-shore erosion and preserving archaeological sites in riparian, underwater and marshy areas. The significance of these Prehistoric sites is unique, both for the international cultural heritage and science, since the objects and architecturai structures made of organic materials, mainly wood, have been preserved in an excellent state due to the humid conditions of their environment; thus, the method of dendrochronology can be successfully applied for the accurate dating of these finds. The scientific reports and discussions were targeting to the evaluation of the preservation efforts and to the improvement of the systems tested so far. Even if the results were not always positive, their presentation helped so that the same mistakes to be avoided in the future. The evaluation of the methods used in various countries and under different environmental conditions proved that each case should have been thoroughly studied before taking any measures; and also that their efficiency should have been sooner estimated. The experience obtained so far is based on experimentations which are, however, susceptible of criticism and improvement. Needless to say, that it is extremely difficult to be decided to which of the numerous sites, endangered by erosion, must be given the first priority.