The stronghold and the village of Mont-Dauphin in the Hautes-Alpes department extend on a more or less stratified fluvioglacial moraine terrace. It consists of puddingstones, a natural amalgam of stones and rounded pebbles held together by stony cement. Very indurated and therefore more spared by erosion, these puddingstones stand in pinnacles above the valley they dominate with their cliffs.