Updated 19th February 1999; 3rd February , 27th October, 18th November 2001; 3rd June,11th November 2002; 9th November 2003; 7th November 2006; 22nd October 2007; 21st December 2008; 21st May, 2014; 1st May, 21st September 2018; 12th, 20th May 2019; 5th September 2021; 4th May 2022

   The GPS reading is on the ledge outside and the entrance grid reference amended from that. A large cave entrance leads up to a goat shelter where it is difficult to leave daylight except through a hole at the end of the eastern limb where a funnel-shaped chamber has a choked 45m pitch in the bottom and a climb to the left leads to a decorated chamber. Another climb ahead leads to a 33m pitch down which chokes at rifts. In 2018, a small, black-floored chamber was entered to the north of the entrance chamber.

   The cave contains 24 groups of schematic-abstract paintings, unfortunately not very well conserved, mostly in the left- hand passage. These are sketched and described in El Arte Esquemático-Abstracto de Matienzo y sus alrededores (Smith Peter, 1998b) and further discussed in Muñoz Emilio et al, 1995 and Ruiz Cobo Jesús and Smith Peter et al, 2001. Sketches from this publication are found here. One group has been dated to around 950BC, however, Ruiz Cobo Jesús et al, 2008, p175 only mentions a date of 11th to 12th centuary AD. There is evidence of palaeolithic remains under the large boulders of the entrance, a layer with bones and flints being visible. The developing Acanto web site (by the Federación de Asociaciones para la defensa del Patrimonio Cultural y Natural de Cantabria) has a section on Arte Rupestre esquemático-abstracto.

According to Quin (BU pp59-62), in his magnetic susceptibility studies, sediments from Coberruyo show similar k values to sediments in Cueva de Rascavieja (077), indicating that the sites may have had a common morphogenic agent and are connected.

Crag Martins (Ptyonoprogne rupestris) were seen in the entrance, April 2014, possibly nesting.

A useful summary is found in Ruiz Cobo Jesús and Smith Peter, 2003 pages 54-56 with a survey and photo.

A short distance east of the entrance is a short climb to site 2575.

The cave was revisited and pushed at the top level on a visit in the autumn, 2007, and the following (edited) account written. The notes 1 to 9 are shown on the amended and annotated survey.

The entrance sediments were covered with large amounts of toilet paper, presumably from climbers shitting in the cave.
This cave could do with a complete re-survey as the passage detail is very confusing especially the entrance and eastern chambers. Entry to the eastern chambers is by a short crawl or narrow rift on north side of main passage (see No.6 below). Interesting features, digs or short extensions are also listed.
Eight bats were noted in the cave, two of which were extremely large, possibly Nyctalus Lasiopterus The others appeared to be Greater Horseshoe. The two larger bats were in the east chambers, two smaller bats were in the east passage and four bats were noted at the end of the west passage exiting the final small chamber.
As to be expected in a cave noted for its archaeological material, bones and charcoal were seen in most areas of the cave. A few bones were also noted in the east chambers though charcoal was not detected.
Sites of interest.
No.1. Small bell chamber at the end of west passage was inspected from which a number of bats were seen to exit, the only way on from this chamber was much too tight, very little in the way of bat droppings were noted in the chamber so it is feasible the bats were roosting further in the cave.
No.2. Area with a profusion of glazed potsherds cemented into calcite floor at base of large stalagmite.
No.3. Passage leads off from this area and would need some rocks pulling out to gain entry. It probably goes to surface, though it could be worth checking out as a possible by-pass for the end choke.
No.4. A short dig at base of two wedged blocks on south side of passage dropped into a small chamber and slope down to a narrow descending tube 3 metres deep. Over the top of the tube a narrow rift dropped down to a continuation of the tube. A short time was spent excavating in this area but was abandoned due to time and a lack of digging implements. Large bones were noticed at the base of the rift: cow sized, possibly Aurochs and certainly very old.
No.5. In the crawling section on the north side of the main passage there is a rift in the roof where one can stand up. On one side of the rift is a shelf where a copious amount of charcoal can be found; on the other side is a similar shelf at the back of which are a number of bones of a medium sized animal. The position of the bones suggests they have been deliberately placed there.
No.6. It is not clear on the survey the route through to the east chambers. The hole through in the centre of the main passage is blocked by formations (picture). Two routes on the north side of the passage unite one in a short crawl; the other is a narrow rift.
No.7. On exiting the crawl through to the east chambers and following the right hand wall for a few metres, a circular chamber with a depression in the floor can be entered. A 3 metre climb down at the base of the chamber reaches a hole in calcite. This was enlarged to drop into a decorated chamber 12 metres long and 6 metres wide and deep.
No.8. Passages missed off original survey - one guarded by nice stal (picture).
No.9. Holes drop away in a calcite choke. This might be worth a small excavation with the right tools. The main continuation of this passage ends in a small chamber with a deep pool and flowstone everywhere.

By August 2018, Peter Smith had completed a re-survey of the cave (below) with a small addition at Easter 2019.

   In 2022, a possible flint knapping stone was recognised and removed due to the credible risk of damage by visitors. The Ministry of Culture was notified about the artefact and it was taken to the Museo de Prehistoria y Arqueología de Cantabria (MUPAC). (A library building on the sea front in Santander, not the display centre in the Mercado del Este). The artefact has a receipt dated 26 Abril 2022 with entry number 2211. Photos.

References: Kendal Caving Club and Manchester University Speleological Society, 1975 (survey); Mills L D J and Waltham A C, 1981 (survey); Corrin J S and Smith P, 1981; Smith P, 1981b (survey); Manchester University Speleological Society, 1982 (survey); pers comm 83; anon., 1986 (logbook); material in file; anon., 1992b (logbook); Corrin J and Quin A, 1992; Quin A, 1993b (survey); Quin Andrew, 1995 (survey); Muñoz Emilio et al, 1995; Smith Peter, 1998b (survey); Smith Peter, 1998a (photo); Smith Peter and Ruiz Cobo Jesús, 1999; Ruiz Cobo Jesús and Smith Peter et al, 2001; Ruiz Cobo Jesús and Smith Peter, 2003 (survey, photo); anon., 2007e (autumn + Christmas logbook); Ruiz Cobo Jesús et al, 2008; anon., 2014b (Easter logbook); anon., 2018c (summer logbook); anon., 2019b (Easter logbook); anon., 2022b (Easter logbook)
Entrance pictures : yes : April 2014 & August 2021 :
Video : entrance with Crag Martins, April 2014 (YouTube)
Underground picture(s): autumn 2007 : Easter 2019 : August 2021
Detailed Survey : 1:1000   amended 2007 : survey Easter 2018 : survey summer 2018 : survey Easter 2019
Line Survey :
On area survey : with Lara-Lennon and Patatal: low res  high res
Survex file : Easter 2019 (Coordinates altered to fit ETRS89 datum, April 2014.)