It’s in the perched synclinal fold of the Gache mountain that the Riou du Jabron, a small torrent that rises in the commune of Saint-Geniez, has carved out a passage that links Sisteron to Authon. This is the Pierre-Écrite gorge, so named because of the astonishing Gallo-Roman inscription engraved in the rock, in the footsteps of Dardanus, prefect of the Gauls and epistolary correspondent of Saint Augustine. One of the emblematic sites on the Route du Temps.