Geological outcrops are of good quality along the foreshore and cliffs in Crozon Peninsula allowing the study of Paleozoic series of the Armorican Massif. The sedimentary and faunal evolution of this area is part of the history of the Gondwana margin and records the opening of the Rhéic Ocean, eustatic variations and paleogeographic migration from high latitudes in the Ordovician to a sub-equatorial position in the Carboniferous. Geological outline of the Armorican Massif is briefly exposed and integrated in a climatic, eustatic and tectonic global framework. Afterwards, the second part deals with formations of the Crozon Peninsula since the Ordovician to Upper Devonian with their faunal and sedimentological characteristics. In the third part, the main outcrops visited during the fieldtrip of the Paleozoic French Group (GFP) during the Congress « Strati 2010 » are described; these outcrops illustrate some aspects of the armorican geological history.