De Martinguinda

The karst is cut by a joint that crosses it from north to south. It is a cavity of clear tectonic origin: a main joint and another secondary parallel one are observed, crossed by another practically perpendicular one that connects them. Entering through mouth no. 1 we find a steep descending slope with numerous clasts. From the landing we can also climb the wall to another hanging window, higher than the previous one. After passing through a narrow crawlway we come out onto some blocks wedged in the secondary joint. From here, downclimbing, we reach a clast ramp. If we go up the ramp we come on the right to a small chamber (white chamber). If, on the other hand, we go down the ramp we come at the end to a pit of 6 metres, whose bottom is a plug of stones wedged in the joint.

The walls of the 3 m pit are covered in moonmilk. In the higher hanging window a lot of moonmilk is observed. The clast ramp is covered in moonmilk, and in the white chamber everything is covered in moonmilk.

Descend the joint about 20 m, downclimb a 4 m step and mouth no. 1 opens in the limestone wall on the left. If from the landing we follow the direction of the joint through a hanging window, we continue along the gallery until it ends in a very narrow joint in which there is a pit of 3 m. If from the landing we take the gallery between blocks that descends, we come out at mouth no. 2, which in turn is joined by a crawlway to the main joint again.

At the entrance of the white chamber a draught is detected. At the lowest point a draught is detected.