14.

Within each cascade takes place a chemical reaction. Limestone, like sugar or salt, has the property of dissolving in water. Now the water that has just crossed the mountain is loaded with dissolved limestone, invisible. The water suddenly begins to deposit limestone because of the combined effect of the rise in temperature and oxygenation. The foams take advantage of the carbon dioxide released during the chemical reaction. Condemned to see the limestone deposited on them and transform them literally into stone, they grow incessantly. The tuff thus created is a material comparable to cellular concrete (lightweight but resistant) much used for construction locally.

The Gervanne is a tributary of the Drôme, 30 km long, it takes its source at the foot of the Col de la Bataille, on the edge of the Vercors cliffs. It hosts a remarkable population of trout fario. Beavers are also found downstream of Beaufort. La Gervanne gives its name to this region of the South-East of the Vercors.

In a verdant setting, the Pissoire waterfall and its small lake offer a refreshing atmosphere. While upstream, in the Canyon des Gueulards, water is scarce here, it flows afloat because it comes from the ravine of the Grand Crot which flows downstream from the karstic loss.

Léoncel is historically a breeding ground, a tradition inherited from the Cistercians. Until the nineteenth century and the optimum population (more than 400 inhabitants in 1856, against about 70 today) deforestation was important to gain land, especially for sheep breeding. Then the forest gradually reconquered the space with the hand of the man, since the post-war it is the cattle breeding which has developed.

The GTV passes a few cables from Léoncel, the village regroups a few houses around a very beautiful Cistercian abbey of the XIIth century. This Romanesque-style building, very stripped of its limestone, is perfectly suited to its surroundings. It is classified among historical monuments since the 19th century thanks to Prosper Mérimée.

It was under the abbey of Jean de Bonnevaux that Léoncel was created on August 23, 1137, with the arrival of 12 monks. The community was erected as an abbey, and its church was consecrated in 1188 by Robert de la Tour du Pin Archbishop of Vienna, the Pope's legate, the bishops of Die and Valencia. In keeping with the peculiar rules of simplicity, this Cistercian edifice of pure Romanesque style is in perfect harmony with the rigor of the landscape. The abbey church has been listed as a Historic Monument since 1854.