Spectacular entrance that leads to a rectilinear gallery oriented N45O and ending 98 metres further on, progressively filled with sediments. From it two branches emerge: the first, a few metres from the entrance, is slightly ascending and ends in a narrow joint almost 50 metres from its start. The second, oriented like the previous one (S25O), is also rectilinear and has an average width of 3 metres. In its first half it has triangular sections. From the place called Pas de l'Oca, the heights rarely exceed one metre or a metre and a half, due to the increase in sediments that end up almost completely blocking the gallery; it is at the end of this that the connection with the Cova del Triangle has been verified, which for the moment has not been physically achieved.

Going back, beside the aforementioned Pas de l'Oca, another conduit is born, parallel to the entrance gallery and with small unimportant branches, which ends in two small pits excavated in the sediments. From this point a union with the Cova Simanya Petita would be feasible, since sounds arrive weakly from one cavity to the other.

It is a cavern formed by an ancient subterranean course, traced over a network joint system (N20E and NW – SE), which must have ceased to function in full juvenile phase and which must have drained a massif much more important than the present Montcau.

Reconstructive phenomena are of very little importance.

In the first half of the second branch there are small pools of water, remains of destroyed gours. In times of heavy rain infiltrations occur that can flood some sections of the cavity.