Émergence de Bessières

The entrance is not natural but built: the works appear very old. A few metres farther on, the natural entrance, almost sumping, can still be seen. On the right, a fossil conduit, an ancient outlet, develops parallel to the active gallery. About ten metres farther on, the two conduits join. The floor consists mainly of stones and clay. The ceiling is never very high and does not allow upright progression. The conduit regularly follows a bedding joint. The flooded part (S1) has an even lower ceiling, and there erosion is intense. Then the gallery becomes somewhat more spacious up to the small chamber 3 m in diameter. It is there that the shaft, about 25 m high and ending in a very narrow joint decorated with roots, is found. After that, we immediately find the 4-metre-long and about 2.50 m deep drop. The gallery seems about to take on new proportions. Unfortunately, a very large collapse, apparently ancient, ends the gallery for us. The width of the gallery never exceeds three metres.

The water of the stream is channelled and flows into an old washhouse that probably no one has used for a very long time. The stream that directly feeds S2 emerges on the left of the collapse, almost at its base.

The exsurgence opens in a clayey limestone. It should be noted that two stages are often in contact: Portlandian and the underlying Kimmeridgian. The semi-permeable Kimmeridgian favours the appearance of springs, emergences, etc.