CH17

a depression 2 metres deep gives access to a fairly narrow meander inlet. a 5-metre step is descended by climbing. Progression continues in the narrow meander descending at nearly 45° to a window giving access to a P6 with a larger volume. This shaft is followed by a fine P12 cut by an intermediate ledge.

At the base of this shaft, one progresses horizontally along a fine fault for about ten metres before squeezing into a narrow crawlway for a few metres, which gives access to a chamber cluttered with blocks. The passage must be sought at the low point of the chamber to reach a new 8-metre shaft. Progression continues in a comfortable fault and an R5 is descended by climbing. a little further on, a P6 gives access to a meander that becomes increasingly narrow. Progression is stopped at constrictions at -108 m.

At the top of the P6, a window on the other side of the shaft gives access to a narrow meander. a particularly narrow and awkward window to negotiate allows a loop of the meander to be bypassed. Progression continues to a bend marked by the arrival of a tributary. The downclimb of a P10 (a little exposed) follows; one must stop 5 metres above the bottom (blocked) on a wide platform then climb back up opposite to squeeze into a small crawlway which gives access, via a 3-metre step, to a new gallery presenting an upstream and a downstream. Upstream, one can reach, via two superimposed galleries, the inlet of a meander explored (but not surveyed) for about forty metres. Downstream, a gallery on a fault leads to a river.

Shortly before the terminus of the downstream river, one can note the presence of fine fossil ammonites in calcium phosphate, which indicate that we are in the Albian.

Downstream, the river has been followed (essentially on all fours and flat on one's stomach) for about thirty metres, stopping at a narrow, aquatic passage. There is no draught in the downstream direction, which seems to indicate the presence of a sump. Upstream, the river has been ascended for about a hundred metres (relatively comfortable progression on all fours with aquatic passages) and exploration remains to be continued. The upstream meander seen previously seems to develop above the river but the passage is too narrow. a significant draught comes from upstream.

With a few slightly exposed downclimbs, the continuation no longer requires ropes. The survey was stopped at the level of the river access.