Trauc de la Veiraria

The small entrance to the cave leads directly into an indescribable zone: an inextricable labyrinth for which no effective description is possible. A narrow joint opens into a spacious passage. To the left, a fine gallery can be followed for 35 metres (-5m). To the right, one climbs up to a boulder choke that is crossed (high point at +2m), then descends again into the choke following a small active stream that is lost in a more spacious gallery.

From this gallery there is access to the lower labyrinth (450 metres of passage!) which contains fine galleries with unusual shapes and ends in narrow meanders (see detail plan) and in the boyau des charbonniers. The access meander narrows abruptly and 10 metres of crawling passage announce the tube and the start of the fun…

One then straightens up in a small rotunda and the tube begins. It is in fact a meander whose top is very narrow and whose bottom forms a rounded passage. After a few constrictions one arrives 90 metres further on at a narrow 90° bend followed by 10 metres of severe constrictions. Then the meander widens and one can stand up to descend this fine meander for a further 45 metres down to the level of -27.50m.

The meander divides in two after 20 metres; to the left one follows a small active stream for 10 metres, stopping at a constriction at -26m; straight ahead, after a few bends, the meander rises and divides again in two and thus narrows; these two small active streams end at constrictions at -23m.

Back beneath the entrance, one follows the gallery downstream to reach the continuation of the cave. All the lateral branches are left aside in this still very labyrinthine part; one progresses westward following the fissuring then, after -19m, the gallery makes a series of bends alternately exploiting the dip and the joints. Sixty metres further on the already modest dimensions diminish and one arrives through a tube at a low point at -32m, this is the passage des feuilles mortes; it can sump.

The continuation for 55 metres is viscous, narrow and wet, if all three at once… One climbs up against the dip to a boulder choke at -27m. In flood, therefore, 100 metres of passage are drowned. The choke is fairly unstable and lower down one straightens up in a collapse chamber. A double joint follows but quickly becomes narrow before joining the continuation of the network. It is better to take a window on the west side which leads into a parallel joint; one follows it for 10 metres to leave it for another parallel joint which is the right one; it comprises an upstream section and a few diverticula then continues and, by way of several bends, joins the other joints. Note that in this sector there are no fewer than five or six parallel passages very close to one another (see survey).

After a final bifurcation one arrives at -38m in another gallery traversed by a stream which is the rediscovered ruisseau des hippurites. One follows it upstream for 60 metres in a fine gallery that stops at a boulder choke at -28m very close to that of the boyau des charbonniers.

Back at -38m, one can traverse an old section along the axis of the stream; it measures 25 metres. The stream continues in a fine meander then follows a narrow fissure that can only be followed for 10 metres. On the left, one can climb a small tributary for 25 metres (-35m); the arrival of this tributary corresponds to the start of a pretty straight meander for 50 metres which is followed high up.

One leaves it to rejoin the stream which can be followed upstream for 15 metres in the continuation of the fissure. Downstream, the gallery enlarges considerably then divides and turns south. The active stream is then doubled by a passage abandoned by the water, communicating with it through several shafts. They finally meet at an impenetrable boulder choke into which the active stream insinuates itself at -48m.

This is the end of this cave, unique in the region, whose visit, despite its modest dimensions, is to be recommended for its sporting character and the spectacle of an original morphology.

A small stream arrives and infiltrates into the blocks: this is the upstream part of the ruisseau des hippurites. To follow it one must cross a very muddy unstable boulder choke. Then it is a wet and muddy meander; one repeats oneself but there are no other words. Moreover, to tell you everything, we strongly advise against visiting this part, unless you are a masochist at heart.

The ruisseau des hippurites and its annexes are cut along a family of more important fractures corresponding to the direction of the faults in the sector.

Nevertheless one can reach the lower labyrinth and the boyau des charbonniers by heading north-north-east. To reach the boyau des charbonniers, one must find a fissure opening on the right-hand wall of the gallery; one arrives at an earthy step, at the same height on the left one can follow a gallery of 15 metres. At the bottom of the step one continues the meander, immediately to the right another meander arrives and gives onto about twenty metres of upstream passages.

One lets oneself descend and slide, accompanied by a small stream, the floor has the particularity of being formed by a very friable and porous black layer which appears to be a sort of deposit of ash and charcoal. These deposits certainly come from the glassworks located upstream of the cave.

Upper Turonian limestones. Numerous fossils are found, notably hippurites. The galleries magnificently exploit the dip and the stratification.

One of the remarkable features of the Veirarià is the presence of labyrinths. In the entrance zone, beneath a surface of 60 m x 40 m, run nearly a km of passages of all sizes, sometimes less than a metre apart, forming a true meshed network on two levels separated by a thin sandstone bed (see section no. 1) with a maximum thickness of one metre. The whole develops over a maximum height of 15 metres and is limited by two sandstone strata. Some passages begin beneath a sandstone layer, others make it their floor, but the majority (¾) remain cut in the limestone beds often exploiting discontinuities. In places only the sandstone bed separates the lower and upper galleries, then less than a metre apart although there may be more than 100 metres of progression between two points. As in certain caves in the chalk (Corbel 1957), the intermediate walls are often reduced to the state of pillars that one would believe artificial. When certain pillars collapse, the galleries join and form small chambers. The formation of these labyrinths remains a problem given their superposition and their resemblances. Chronologically, the intersection of certain galleries shows that there have been several phases of excavation. It is even possible that the two labyrinths formed more or less at the same time for a majority of passages and this by several different and independent arrivals of water as is still the case in certain portions of the cave. Finally the mode of excavation remains to be determined given the few micro-forms or deposits observable.