Updated 5th September 1998; 19th February 1999; 3rd, 25th February, 27th October 2001; 3rd June 2002; 9th November 2003; 27th October 2007; 22nd December 2008; 10th January, 16th May 2009; 30th June 2018; 16th June 2022

The gated entrance is situated at the head of a steep grassy field and is about 35m wide and 5m high (photo). The floor of boulders slopes away into very large passage with large formations (photo) which ends after 200m at a climb up greasy calcite. A sloping 25m pitch gives access to a couple of small grottos. A slippery calcite climb up for 25m from the pitch base gains the main passage continuation - this is normally reached by a lined, slippery traverse around from the pitch head. A couple more climbs over calcite give access to a boulder slope down and then a calcite climb up to the final wall. 1985 saw much climbing activity on the right before the end but the heights reached only confirmed that the S.E.S.S. had been there years before .

The bats Rhinolophus ferrumequinum and Rhinolophus euryale are listed by Meijide (AY).

The entrance chamber contains extensive Magdalenian remains. The right hand wall has two panels of engravings: the first of two deer, and the second of several figures difficult to interpret, and certain animals; deer, goat, bovid and a possible reindeer. Large amounts of pottery have been found and there are several groups of schematic-abstract paintings, mostly along the right- hand wall. These are described and discussed in El Arte Esquemático-Abstracto de Matienzo y sus alrededores (Smith Peter, 1998b) and Muñoz Emilio et al, 1995. (Archaeology link).
El Diario Montañés (9/1/2009) reported the jail sentence and fine given to 2 men caught by the Guardia Civil in 2006 as they were illegally excavating and removing bones and other items. The reference Ruiz Cobo Jesús and Muñoz Fernández Emilio et al, 2009 describes the deposits in the context of the Asón caves and has a comprehensive summary.

Morlote Jose M et al, 1995 describe Cobrantes as one of the Iron Age sepulchral caves in the area.

The villagers say that the cave contains a golden bed, and a golden skittles alley where the Moors played.

References: Fernández Gutiérrez et al, 1966; Kendal Caving Club and Manchester University Speleological Society, 1975; anon., 1978 (logbook); Corrin J et al, 1978 (survey and photo); anon., 1979 (logbook); Addis F et al, 1979; Manchester University Speleological Society, 1982 (survey); Corrin J et al, 1981b; Smith P, 1981a; Corrin J S and Smith P, 1981; anon., 1981a (logbook); Corrin J et al, 1981a; Corrin J, 1983c; anon., 1985b (logbook) (survey); Cawthorne R, 1987; Corrin J, 1986; material in file; Echegaray et al, 1966; Smith P, 1986b (survey); Meijide Calvo M, 1982; Muñoz E et al, 1986; Fernández V, 1988; Muñoz E, 1988; Smith P, 1988; Corrin J, 1992b (survey); León J and Smith P, 1993; anon., 1994b (logbook); Corrin J, 1994b (survey); Morlote Jose M et al, 1995; Muñoz Emilio et al, 1995; Smith Peter, 1998b (survey); Smith Peter, 1998a; Ruiz Cobo Jesús and Smith Peter et al, 2001 (includes drawing of an urn); Smith Peter, 2002; Ruiz Cobo Jesús and Smith Peter, 2003 (drawing of urn); Corrin Juan and Smith Peter, 2007; Ruiz Cobo Jesús et al, 2008; Ruiz Cobo Jesús and Muñoz Fernández Emilio et al, 2009 (survey);
Entrance picture :
Underground picture(s): yes
Detailed Survey : from 1978: low res  high res
Line Survey :
On area survey :
Survex file : 1978 (Amended magnetic declination December 2013 to align with Eur79 grid and coordinates altered to fit ETRS89 datum, April 2014.) : 2022 with reconstructed LRUD
Passage direction rose diagram: 30/6/2018