Aven de la Masse

The entrance (0.8 m x 0.6 m) opens at ground level. A vertical descent of 2 m and an 8 m crawl lead to the -6 level, at the top of the first shaft. Before it, on the left, a southwest–northeast fissure 5 metres long is left. After 2 metres of inclined plane, the shaft opens into the ceiling of the cavity's main chamber. Six metres of vertical descent allow reaching the side of a scree slope of fine gravel at the heart of a vast chamber (20 m x 13 m). At the north end (upstream of the chamber), the scree flows from a chimney quickly blocked by a fill of clay and stones. At the east end, a short descent leads into an ascending chamber (10 x 6 m). The low point of this chamber lies at approximately the -29 level. Toward the back of the large chamber, on the left, a small vertical opening opens in calcite blocks. From a niche, 2 metres below, a 6-metre shaft leads to the terminal chamber (8 m x 4 m x 6 m). The low point, clayey and rocky, of the cavity is found in this austere chamber at the -34 level.

At the east end, skirting a large stalagmitic pillar, a short descent leads into an ascending chamber. At the bottom of the regular scree, one passes a curtain of speleothems. The low point of this chamber is reached to the right of the scree by a nicely decorated passage.

Along the right edge of the decorated passage, a regular flow of clay proves the temporary arrival of water.

The decorated passage ends after about twenty metres. Turning around, one can reach the bottom of the large chamber by a descending passage. The start of the second shaft is dangerous because it consists of a flimsy platform (rocks over the void held in cantilever).

WARNING: we strongly advise against visiting this part of the cavity, which, moreover, is completely lacking in interest.