O La Merienda de Negros (a37)
Explored by SEG in 1988 to a depth of 46 m. Due to its variable narrowness, its complete exploration cost a week of hard effort, enveloping a significant part of the expedition.
The cave begins with a narrow crawl of 4 m which ends to the left of the first pitch (Pozo Eskakeate) of 12 m, disgustingly muddy with abundant loose stone. After a boulder slope opens Sala de los 1000 Dientes, accessed by a P9. The chamber's dimensions are 37 x 18 m and its name is derived from the enormous calcite crystals of "dog teeth" that upholster its walls.
At the opposite end of the entrance pitch opens a crawl (Ukrania 1943), practically filled by a viscous mud for which it was necessary to laboriously dig out. The crawl ends at the head of a P25 (Pozo Gateras) formed by unsupported unstable blocks leaving a space of 60 cm between the blocks and the ceiling. Two spits in the left-hand wall enable descent of the pitch. at its base a small active vadose trench disappears into an absolutely impenetrable hole. The water comes from a parallel shaft from which the strong draft presumably also comes from that circulates around the crawl.
The cave is in the base of the hillside north of the line Cuetalbo-Punta Extremera.