On the boulder of Bicarburation, at the end of a quarry, under the plateau, to the left of de La Route des Gorges de Franchard, in direction of La Gorge du Houx. Start at the right pillar of the bivouac entrance, climb the roof and exit via a mantle.
Access : at the end of the paved road, go up the hill to the plateau; the boulder is behind a tagged shelter at the end of the quarry.