Aven du Colombier

The entrance consists of 3 openings. It is followed by a gallery 1.5 metres wide that divides into two branches after 35 metres. To the east, the gallery continues, descending and winding, to a chamber 6 m x 10 m in the centre of which a P 6.5 drops into a blind niche at -16 m, the lowest point of the cavity. To the south, after about fifteen metres, the gallery becomes ascending (concretionary flowstone). Several passages present themselves: on the left, an initially steep conduit opens in the ceiling of the large lower chamber and continues to a crossroads. On the left, a descending gallery towards the north-east down to -7.5 m ends at a choked chimney. Opposite, an ascent meets at + 4 m an east-oriented downward gallery, ending after 40 metres at -3.5 m after a substantial widening. The start of this gallery is on the left side of a fine P13 reached by the right-hand branch beginning at the top of the concretionary flowstone. This shaft, of good dimensions (3 m x 4 m), reaches -6 m in a north/south gallery quickly blocked to the north. To the south, it ends at a funnel in the clay that must be crossed to reach a 9-metre crawlway, 50 cm high, which leads into a 17-metre section of gallery, filled with clay. Facing the outlet of the crawlway, a passage leads to the base of a double chimney 10 metres high, to be revisited.

The south branch becomes ascending over a concretionary flowstone; the right-hand branch begins at the top of this concretionary flowstone.

The cavity develops in black platy limestones of the Gothlandian.

Strong presence of horseshoe bats. DO NOT VISIT IN AUTUMN / WINTER.