The quadrangular mouth gives way to a shaft with an average width of 2 metres and a length of 8 metres, which increases as it deepens. This shaft has a vertical drop of 22 metres and its base is considerably elongated, following the main joint of direction E36N – 036S. From the foot of the vertical, occupied by a large debris cone, two steep slopes of clastic material emerge; towards the NE it is 15 metres long and has its ceiling and walls beautifully decorated by stalactitic formations. The SW gallery, after a vertical drop of 4 metres, descends at a slope of 40º to the mouth of a new shaft, of 5 vertical metres, which leads onto a new chamber of elongated section practically in the same direction as the rest of the pit. This new chamber is nothing more than the lower part of the single cavity, which is divided into multiple parts by the clastic accumulations.

Its origin seems to be due to the erosion or dissolution of a stretch of limestone, practically disappeared, within the package of schists predominant in the area.

In a later survey (SIS – CET, 1978), a small side chamber appears, reached by means of a narrow passage located at the foot of the entrance shaft and which does not seem to be reflected in the first survey.

The reconstructive process is represented by a large parietal flowstone in the central part of the base of the entrance shaft, and a considerable quantity of white stalactites and stalagmites of regular sizes, among which are some eccentric and isotubular ones, as well as beautiful needle crystallizations.