Tanne du Miroir

The entrance gallery is fairly spacious: 2 to 5 m wide and 3 to 6 m high; its floor is cluttered with a practically continuous boulder chaos over 50 m. Further on, the floor becomes smooth and calcified. The gallery, noticeably narrower but correspondingly higher, becomes straight, enlivened by a few low passages due to calcite fillings. A 20 m pit interrupts this straight passage; relatively narrow at its base, it widens with height and tops out at 30 - 40 m above the stony floor. The latter becomes chaotic in the following gallery, reached after a slight ascent between collapsed blocks. This is followed by an ascending pit whose artificial climb was undertaken over 20 - 25 m. At its foot, the collapsed and sloping floor gives access to a long crawlway between the stone chaos, which narrows 10 to 15 m further on, preventing any continuation.

The floor of the gallery becomes smooth and calcified; a few low passages are due to calcite fillings.

20 m pit: 25 m of rope. The artificial climb of the ascending pit was undertaken over 20 - 25 m.

The uniform and straight section of gallery reveals a fine fault mirror between its flat and narrow walls. This fault, which shapes practically all the rest of the system, is in fact the normal continuation of the large fracture which, further south, shapes by counter-effect the trou des Suisses (RL 65).