Lésine des Pres Barres

The entrance takes the form of a vertical fissure 40 cm wide and 1.5 m long. After a few steep metres over earthy ground, a 44 m vertical drop begins, broken into three sections with a well-marked ledge at -32 m, beyond which the pit splits in two. Throughout its height the shaft remains comfortable, with a diameter varying from 1.5 m to 3 m. Past the entrance zone the walls are of very corroded bare rock.

At the base of the vertical drop one lands in a gallery of good dimensions. On the right begins a fine passage 4 to 5 m wide and 3 m high that descends gradually towards the east. After about fifty metres the passage lowers little by little, partially filled by a compact Clay filling.

On the left of the gallery, progress is very quickly stopped by a low and uninviting sump.

Only a low vaulted passage allows further progress for about thirty metres before ending in a total obstruction. At two-thirds of the shaft it is possible to reach the start of a crawlway that gives access to a series of chimneys rising towards the surface.