The entrance of 1 x o,5 metres allows us to pass into a shaft that is narrow at first, but elongated, which at 10 metres widens notably and 6 metres later reaches a step formed by a large wedged block. We can descend 8 metres more, where the shaft lengthens a little more, maintaining, however, its width of 2.5 metres. We arrive above a pile of large blocks of clastic origin in a N direction and, climbing back up with difficulty, a small hole is reached, after passing which we arrive at a chimney 12 metres high up which one must climb very delicately.

A few metres away we find a second hole on the S side, which communicates again with the shaft of the pit. This chimney ends in an uncomfortable step, where the joint that formed it becomes very narrow. Returning to the pile of large blocks at the foot of the shaft, one can descend among them without difficulty by the NW end, quickly following a ramp that leads us to a chamber measuring 6 x 4 metres. The irregular ceiling reaches 6 metres in height in some places. In the lower part of the chamber, the NW end, two galleries appear. The one more on the E side is quite narrow and can be followed for about 6 metres. The ceiling becomes narrower, not exceeding 5 metres. The second begins with an annoying low passage that, once passed, leads us to a gallery of 7 metres, wider than the previous one; the ceiling is higher: it reaches 8 metres in height. In the walls of the gallery several quite large blocks are wedged. The N end of this gallery is where the cavity reaches its maximum depth (-36 m). Near this point, at floor level, we will find a hole, on the E side, through which one accesses the first gallery mentioned.