Grotte de Picabas

The main gallery, wide and short, begins with A 3-metre shaft (1.7 m x 0.7 m) and is characterised by A tubular shape; A small clogged crawlway lies at the bottom of the descent shaft. It continues as A short meander that opens into A wider and more complex gallery. The floor, made of scree, gives way to A calcite slide giving access to A chamber that is none other than A shaft-chimney linking the 4 levels; the gallery ends in A narrow, muddy meander.

The intermediate gallery, very short, is accessible through A sloping opening located in the "chamber" above the shaft; it rises then descends again to end at the very bottom of the "chamber", and it is clogged at each end. It is A fine, almost tubular phreatic conduit.

The upper gallery, relatively wide and decorated with speleothems but low and A little muddy, ends on A stalagmitic flow. Its initial chimney allows reaching the highest point of the cave, which is in fact A blind shaft.

The lower network comprises A low gallery that gradually rises to become higher, A narrow meander presenting A severe passage that leads to the lowest point of the cavity (clay clogging), and, shortly before the end, another sinuous phreatic-conduit-type gallery also ending on A clay clogging.

The cavity is divided into 4 clearly distinct parts: the main gallery (62 metres), the intermediate gallery (16 metres), the upper gallery (26 metres) and the lower network (81 metres), for A total development of 185 metres.

The upper gallery is decorated with speleothems and ends on A stalagmitic flow. A few helictites are visible in the lower network.

A weak permanent water flow is lost towards the bottom of the lower network.

The upper gallery is reached either from the start of the intermediate gallery, or by crossing from the end of the slide above the shaft; one must then squeeze into A vertical fissure opening onto A chimney, where the gallery begins.

Access to the lower network is found at the start of the main gallery: one must squeeze between the blocks in an "antechamber", then into A narrow and slippery 4-metre step. In this gallery, A small step with no continuation has been opened.

Like the aven Kif, which lies on the same side of the syncline, all the galleries follow perfectly the dip of the strata (35 degrees), heading due north towards the bottom of the syncline. All the galleries are parallel and rigorously follow this dip (35 degrees).