A21

The entrance of the A21 is formed by a pretty meander three to four metres high. a few metres from the entrance opens a magnificent P30 which gives access to the lower meander. The upper meander, 6 to 10 metres high and fairly narrow, has been explored and surveyed over about 110 metres. The lower meander is punctuated by selective constrictions; a widening after 60 metres allows one to emerge into “the great meander”, surprising for its more than comfortable dimensions. Around a bend, the meander resumes its “selective” dimensions over a little more than 100 metres in length, before becoming a little more “human” again. The phreatic pipe leads us, after a small climb, to a vast chamber which is in reality a crossroads of several galleries. The continuation upstream is in reality a small gallery 1.2 metres in diameter. The puits Taré is about 5 metres deep; its floor appears impenetrable, but two meanders start at its top. The “galerie des Oursons” is perfectly circular and 3 to 4 metres in diameter over thirty metres in length. a new meander is about fifteen metres deep but its floor is impenetrable. The great chamber is excavated at the contact of an impressive bedding joint between the beautiful limestone of the A21 and the layer of dark sandstones which geologically separates us from the Jean-Bernard.

The active stream of the meander, which can be significant in times of flood, is lost in an impenetrable fissure. The draught very probably rushes into one of the two meanders starting from the top of the puits Taré. a small triangular gallery, “invigorating” thanks to its draught, opens into a pretty phreatic pipe. In the “trémie de la Frayeur”, the draught passes through. We hear the active stream a few metres from the floor of the new meander, but without being able to reach it.

One progresses by opposition in the upper meander; the route through the lower meander with a kit is quickly gruelling. a small climb allowed a side passage of little importance to be explored. It is possible to climb back up to the top of the meander to reach the upper fossil phreatic pipe, irremediably choked towards upstream. Towards upstream, the main phreatic pipe ends at a shaft rising impenetrably at the top; the logical continuation of the phreatic pipe is located at the top of the chamber and a climb was carried out to reach it, but a choke annihilated all hopes of continuation. After a climb and a constriction, one arrives at the top of the puits Taré; a few spits are necessary to reach the two meanders, but the lack of equipment did not allow us to continue the exploration of this upstream further. In the chamber, the downstream is found by slipping between the blocks on the right. Upstream of the phreatic pipe, one arrives a few metres further on at a climb; at its base opens a “boyasson” which, after a few metres on all fours, opens out again into the “galerie des Oursons”. The “trémie de la Frayeur” rises but one must dig under the unstable scree, and find a way to dig safely to avoid taking everything on one's head. The top of the climb leads to the top of the “puits Vert”. a small shaft that we downclimb leads us to a small labyrinth of partly choked phreatic pipes excavated on a bedding joint. a descending ramp, then ascending, allows one to emerge into a small boulder-strewn chamber. a dig in the chamber allowed the “galerie des Ours” to be reached; a short dug ramp allows one to reach the lower exit of the cave, the A24, which opens in the depression of the A22, a few tens of metres from it.

The “galerie des Oursons” owes its name to the presence of three bear cub skeletons caught in the fill. The “galerie des Ours” is furnished with bones and bear wallows and has been marked out to protect the site. At this level, a voice connection was made with the low point of the “galerie des Oursons” and bear bones litter the floor in various places. Several accesses allow one to reach a meander which unfortunately pinches out. a meander arrives from the ceiling of the small boulder-strewn chamber, but quickly becomes impenetrable. The continuation of the phreatic pipes has surely been revealed by erosion and the hope of continuing their exploration is slim.