Armorican Massif

French  Massif Armoricain,  flattened erosional upland, or peneplain, encompassing the western French départements of Finistère, Côtes-d'Armor, Morbihan, and Ille-et-Vilaine and parts of Manche, Orne, Mayenne, Maine-et-Loire, Loire-Atlantique, and Vendée. The region has an area of approximately 25,000 square miles (65,000 square km) and is bounded by the Paris Basin and the Seine River to the north and by the lowlands