5. A brief overview of the geology of mainland France

In keeping with its diversity of landscapes, France also boasts remarkable geological diversity, given its relatively small surface area, including a wide variety of metamorphic, magmatic and sedimentary rocks. For the most part, the rocks outcropping on the surface cover the very end of the Precambrian and the whole of the Phanerozoic (figure 21 ). Older terrains dating back some 2 billion years are present in the form of small (multi-kilometre?) "relict" gneissic bodies preserved within more recent entities of the Armorican Massif, in Northern Brittany and on the tip of the Cotentin peninsula.