Lizarraga I

The entrance is a joint of scant dimensions whose direction is W-E. It has two access mouths: the first, of smaller dimensions, is located in the E part, while the second, somewhat wider, is on the W side. The plan of the pit is interrupted on one of its sides by blocks fallen from the roof and walls, while on another side it closes by narrowing of the joint. The wall is extremely bare due to the constant erosive action of the water seeping through this cavity.

It descends vertically for eight metres, at the end of which there is a debris plug that makes further progression impossible. It can be descended without any kind of equipment, since the ascent and descent can be done by free-climbing.