Le Point sublime

On the other bank of the Berthéou valley, it is possible to see a light-coloured, almost white, cliff: it is made of quartzites from the Triassic period, resting directly on top of the recognisable red pelite of the Paermian era. This extremely compact rock was used on site to build the beautiful Berthéou viaduct, constructed at the beginning of the 20th century for the steam tramway which ran to Guillaumes. Quartzites can mainly be found in the “giant’s cauldrons” in the Berthéou valley, where they played an essential abrasive role. These natural swimming pools are a delight for fans of canyoning.

Much mystery still surrounds these pelites…when you visit this site in May, you will notice the one plant seems to particularly enjoy growing on these unpromising areas with these rocks: saxifrage icequeen (Saxifraga callosa). This plant which grows in rocky areas decorates the red cliffs in spring with its delightful clusters of flowers, whereas its leaves have a rough or even sharp edge. Looked at through a magnifying glass, the edge of the leaves really looks like a small saw: the plant gets rid of its excess minerals via the edge of its leaves much like glasswort does with salt.