Grotte du Barthas

The entrance, somewhat narrow, is followed by a short "ramping". One drops into a very small chamber. Passing over and down-climbing a tufa flow, one reaches a low chamber obstructed by a scree cone. In flood, the water escapes through a narrow meander that quickly becomes impassable. Taking the P18, one leaves the fossil section to reach the active level in a comfortable gallery with a sandy floor. The downstream of this conduit leads, after a low passage, to the emergence of the field already mentioned (the junction was made by voice). About twenty metres upstream of the shaft is a crossing. On the left, the gallery that developed along an inclined joint goes towards a second temporary emergence. On the right, the gallery is a phreatic tube. After a few bends and a regular lowering of the roof, the gallery plunges into a small sump. The fossil section — and in particular the shaft — seems to have been overdeepened.

This cavity belongs to the Martel causse which, because of its heavy filling (siderolithic), is poorly penetrable. One of the hopes therefore lies in the search for the outlets of the underground rivers. The emergences of the Barthas apparently function as an overflow. After heavy rain, the field is flooded, which completely drowns the lower level of the cavity.

On the left, one then reaches the P18 which links the two levels of the cavity.

There is little hope of continuation in this cavity, the only penetrable gallery of this karst being blocked by a sump that appears impassable.

Geology: Callovian limestone[ref]Explorations - Spéléo - Plongée > Grotte du Barthas 2011: http://explorations-speleo-plongee.eklablog.fr/grotte-du-barthas-2011-p885670[/ref].