La coupe de Porz ar Vouden (Pridoli de la presqu'île de Crozon) Massif Armoricain, France – Lithologie et Biostratigraphie

The Porz ar Vouden section in the Crozon peninsula (Finistère, France) has a particular interest because of its place in the late Silurian badly known up to now in the western part of the Armorican Massif. The lithostratigraphical analysis allows to set up a boundary between the Lostmarc'h Formation and the Plougastel Formation. The complete paleontological study gives a good approximation for the datation of the basis of the section (Pridolian) and that of the lower part of the Schistes et quartzites de Plougastel, pridolian too. The simultaneous occurrence of Clarkeia and Salopina leads to some considerations on the paleogeography.