Gouffre du Mont Friloux

This cavity is of tectonic formation and takes the form of a labyrinth of fissures that intersect in many places. It begins with a succession of small steps requiring no equipment, then one quickly emerges at the top of a high diaclase, which must be descended. The route then continues through galleries of medium width, ranging from 40 cm to one metre, with a height varying from 1 to 7 metres. In the most spacious part, heading north, there is a 6-metre-high corridor that can be followed easily for several tens of metres.

The terminal gallery is the finest, with a few calcite flows adorning the walls.

It is essential to carry the survey if you wish to reach the most spectacular part of the cavity: the route is far from obvious. Only the terminal gallery is worth visiting, but the route to reach it is complex.

The most interesting route is the one heading south, at the bottom of the entrance gallery. One follows a gallery for about twenty metres, generally on all fours. At the second junction encountered, one must follow a gallery that climbs towards the west. Then follows a succession of fissures, often narrow. Galleries that are sometimes more spacious are intersected, but they are obstructed at their ends. It is at the exit of a new constriction that one emerges into the most spacious part.

Heading south, one must cross a zone of fallen rocks to find its continuation. Often intersected by loose rubble slopes or narrowings, one must sometimes look for a passage at the bottom of the diaclase or behind a few blocks that bar the way. The gallery thus continues for several tens of metres. However, increasingly severe constrictions slow progress. It becomes pointless to try to force these passages, reserved for the thinnest, beyond which the visit offers little interest.

Source: Site du Spéléo Club de Chablis (SCC) > « Grotte du Mont Friloux (89042 - Bierry-les-Belles-Fontaines) » -- https://www.scchablis.com/Site/Speleo/Invent/89/89042/mont_friloux.php