Updated 6th November 2003; 9th February, 28th April, 16th July, 12th, 17th October 2016

   The entrance is above the stream sink in the large Hoyo Frio depression. A crawl to left just inside the entrance leads to a streamway which descends with some traverses to a sump after 250m.

   By carrying straight on at the entrance, a maze of passages is entered which eventually reach a roomy gallery. To the left are a couple of short choked passages. (See below). Eighty metres further on, a sump is reached after some crawling. This sump is at the same altitude as the first and both are connected by a short, constricted passage. A round trip is therefore possible.

   At Christmas 1996, an extension was made at "cont" on the 1975 survey, on the right hand higher level through a flat out section to a metre high area. Up in the roof at cross section l a flat out crawl needs pushing to a drop, which may return to the streamway. It may be worth spending more time pushing around here to the north east. At the western side of the cave, the ? ? at F8 was explored down to a small streamway on the north side and a climb up on the south side to a choked passage heading back into the cave. A climb up beyond cross section r entered a passage with a calcited choke which was removed and a choked rift entered on the other side.

    Pete Smith is resurveying (2015, 2016) the whole cave, as the original Spanish survey in reference La depresion cerrada de Matienzo (Fernández Gutiérrez et al, 1966) has passage not shown on the later survey. During this resurvey, a tight rift with daylight at the top was seen and later found on the surface. (See site 4276.) The cave length, shown above, is the length of this resurvey, so far.

   The cave was given its name (Mad Woman) because a woman called Ramona stayed in the cave for a week, some fifty? years ago (in the 1950's?). She eventually left through another entrance which has since been covered over.

   In the Catalogo de los Quiropteros de la provincia de Santander (Meijide Calvo M, 1982) there is a record of one bat species, Rhinolophus ferrumequinum.

Link to entry in the Cave Diving Sump Index.

References: Fernández Gutiérrez et al, 1966 (survey); Kendal Caving Club and Manchester University Speleological Society, 1975 (survey); Fernández Gutiérrez J C, 1975; anon., 1975a; Manchester University Speleological Society, 1982 (survey); Cox G, 1973; Mills L D J, 1981; Mills L D J and Waltham A C, 1981 (survey); Corrin J S and Smith P, 1981; Meijide Calvo M, 1982; anon., 1996c (Christmas logbook); anon., 2016a (January, February logbook); anon., 2016c (summer logbook)
Entrance pictures : yes
Underground picture(s): summer 2016
Detailed Survey : from 1965: low res  high res
from 1975: low res  high res
from 2015/2016 : pdf
Line Survey :
On area survey : 1975 Ozana area map. Not a lot of detail. low res  high res
Survex file : yes (After summer 2016; resurvey - work in progress) : with other caves in the area (after summer 2016)