A Châtelperronian open-air site in the Paris Basin: Les Bossats at Ormesson (Seine-et-Marne) [Un gisement châtelperronien de plein air dans le Bassin parisien: les Bossats à Ormesson (Seine-et-Marne)]

Les Bossats site at Ormesson, in addition to its Badegoulian, Solutrean, Gravettian and Mousterian levels, has also delivered a Châtelperronian occupation over a large area, in the form of a thin layer and whose integrity has not suffered from mixtures, or to a very limited extent, with older or newer layers. This occupation has been excavated in two test-pits, test-pits 3 and 50 of respectively 16 and 2 square meters, but with an estimated surface area of 150 square meters. This level already delivers a certain amount of information concerning the lithic industry but also the colouring materials, already present at Ormesson in the Mousterian level, as well as on animal and vegetable resources. If in the years to come efforts are directed towards the exploitation of the younger levels, we plan an extensive excavation of the Châtelperronian in 4 to 5 years. In the meantime, this article is intended as a first presentation of this new Châtelperronian occupation, the northernmost one known at the present time. But it also lays down a certain number of milestones concerning the characteristics of the lithic industry, especially the blade production, through the realization of numerous explicit refits and also the presence and role of bladelet production. In this sense, the Ormesson site is an obvious part of the debate concerning the microlithic productions of the Châtelperronian and the relations which this so-called transitional industry was able to maintain with the Mousterian, as well as with the Proto-Aurignacian. Like their Mousterian predecessors, but also like the groups that occupied the site after them, the Châteiperronians from Ormesson undoubtedly benefited from a particular topography of the valley at this point, favourable to the driving of game. Like them, they were also able to find water, vegetal resources and flint nearby. Like them, their occupation was rapidly covered by sediments, sandy in this case, which allows a relatively new palethnographic analysis for this period. The small size of the surface presently excavated is certainly a limitation to the overall economic and functional interpretation of this level, but it does not prevent a fairly detailed questioning of the various categories of tools represented (knives, burins) or absent (end-scrapers) in the current state of the excavation. The first results of the faunal and charcoal analysis are presented, enriching this documentation, on the technical side, with more contextual data. In spite of a certain geographical isolation, les Bossats are nonetheless part of a 'northern' Châtelperronian territory which includes the famous Renne at Arcy-sur-Cure or Roche-au-Loup at Merry-sur-Yonne (Yonne) caves. Some initial comparisons are outlined with these two sites. A discussion is also initiated about this apparent scarcity in Châtelperronian sites north of the Loire River, which is perhaps more related to the actual state of research rather than to a real lack of occupations.