Once formed, the massif underwent severe erosion, which accentuated the relief. The different synclines grew larger, eventually forming valleys including those of Autrans, Méaudre and Lans, Villard, Corrençon, the Col de Romeyère and the Col de Rousset. The water hollowed out the cirque of Archiane, the Steephead valley of Bournillon, and the combe Laval.