Amidst the waves, the Roc’h Santeg Leton rock shelter (Santec, Finistère): An urgent excavation of Middle Palaeolithic to Iron Age occupations in stratigraphic position

The excavation of the rock-shelter of Roc’h Santeg Leton (Santec, Finistere) have been made in 2015 and 2016. This emergency excavation on the islet is linked to research programs on armorican rock shelters (“Take Shelter!” program) and on the erosion of coastal heritage (“ALeRT” program). D. Roue discovered the site in 1985 on a rocky islet 1300 m from the coast. Nine periods of occupation have been identified recorded in a 1.10 m thick stratigraphy. Relatively modest, the archaeological artefacts collected during the excavation includes shards, charcoals, rare hazelnut shells and lithic pieces (flint, quartz, granite macro-tools). The Middle Paleolithic is attributable to a recent phase of the Middle Paleolithic, either during MIS 5 (5d/5a), or during the Weichselian (MIS 4 to 3). Mesolithic lithic pieces are related to the Bertheaume Group (Early Mesolithic) and the Teviecien of Beg-er-Vil facies (Late Mesolithic). At the top of the stratigraphy, a small bowl-shaped hearth is radiocarbon dated to the late Gallic period (La Tene) and accompanied by shards attributed to the early/mid Iron Age. A small contemporary pit was filled with shells, mainly limpets. The geoarchaeological analysis shows that the “littoral” signal is not perceived through the soil-sedimentary dynamics, which is largely controlled by colluvial inputs and concentrated runoff. This excavation validates fast methods for maritime prehistory, from which water sieving, the only means of correctly sampling prehistoric sites, is never excluded.