OUCC Proceedings 4 (1966)

Report on the British Speleological Expedition to the Cantabrian Mts., Spain, Summer 1965

.A.C.W. Robertson

Several members of this club took part in the British Speleological Expedition to the Cantabrian Mountains during the long vacation of 1965, and we feel that a report of the findings of the Expedition should form part of the proceedings of the Club. For a fuller and more detailed account of this Expedition the reader should refer to the report due to be published by members later this year.

The Expedition was first planned in November 1964 and was intended to be quite small, not more than about ten members. We got into contact with a Spanish caving club based on León, the Grupo Espeleólogos de Peñalba, who appeared to be quite pleased at the prospect of a thorough exploration of their area. Partly on the strength of their reports, the Expedition grew to its eventual size of thirty. We were lucky in receiving large numbers of gifts of food and equipment from industry, but about three thousand feet of electron ladder had to be assembled.

On arrival at León, we were taken to the camp site prepared for us by the Spanish potholers, about twenty miles north of the city. This was situated in a polje whose floor was at 1200m, surrounded on three sides by mountains and quite heavily afforested. The first few days were spent acclimatising to the extremely high daytime temperatures and arranging methods of exploration with the Spaniards. This had to be done in two ways: firstly, caves reported by the Spaniards had to be thoroughly investigated by us, and secondly, the surface had to be searched methodically in the hope of finding new systems. The first provided many disappointments as most of the caves did not realise their full potential as reported by the Spaniards. I shall give a brief description of these.

Sima Graíl:	180’ entrance pitch onto slope of rubble and guano. Below the slope a further pitch of 75’ ends in an impassable floor of rubble. Above this pitch a rift continues upwards, but not to the surface. There are no horizontal passages.
Sima el Solitario:	Near Sima Graíl, on the south side of Peña Cimera. Another shaft with a large entrance. Drops to 80’ and then chokes.
Pozo de los Grajos:	On the south side of the mountain Moneca. Shaft of 150’ leading to snow. This is domed indicating that it could have been formed by a standing column of water. There are no horizontal passages. North of this there are three small shafts, depth 60’, which connect at their bases.
Cueva del Pozo de Infierno:	A resurgence cave in a large rift opening into the base of the Torío canyon. This extended almost horizontally into the side of the gorge and took a lot of very cold water. The rift was 60’ high in places, with very deep water. Ended in a sump in which diving was attempted. Attempts to climb over the sump were made but these were abandoned.
Cueva del Valle del Marqués:	This influent cave occurs in Devonian limestone in an enclosed valley on top of the mountains on the east side of the Torío gorge, above Rodillazo and Tabanedo. The entrance may take a large amount of water in the spring, but only pools remained in the summer. A large entrance rift leads via alternative passages into a rift at right angles. After a few hundred feet a stream is met flowing across a small chamber. Above this the rift could be climbed into a long boulder choke. Both above and below this choke a way might be forced with care, as chambers could be seen through the boulders.
Cueva de Valporquero:	This is without doubt the finest system explored so far in the area, and part of it is being converted into a show cave. Below the public part there is an extended passage taking a stream which offers an extremely worthwhile trip. At present a survey is being drawn, and our estimate of the length as 1 - 1.5 km may be very inaccurate. The entrance lies in an uvala on the south side of the village of Valporquero de Torío. An influent stream enters the cave, which drains the Sierra del Gato about 3km to the west. A wide entrance leads into a largely dry upper series of well decorated passages. The stream sinks to reappear lower down the system. An inlet stream can be followed up through decorated chambers containing pools for some way. These are probably beneath the deep, conical doline to the east of the cave entrance and the curious forked rock formation above it, known as El Cogullón. The way down is through a narrow passage 300’ high, called El Cañón, and then a climb down through boulders to the stream. After swimming through some deep pools, one reaches a high passage at the end of which the stream flows over a flowstone cascade of depth 70’. This is formed in a domed chamber about 300’ high, with a flowstone floor. The stream passage is followed through more large chambers involving two 20’ slides into deep pools. Finally the stream sumps in a large chamber. A thin M-shaped tube ( in elevation ) on one side of this chamber gives access to a daylight chamber out of which the stream emerges. The resurgence is about 200’ above the Rio Torío.
Of the caves discovered by the Expedition members, only two are of any importance, and I shall describe only these.
Sil de la Colombina ( Ghyrrt Cavern)	This non active cave is on the side of the Pico Polvoredo above Correcillas, the entrance being about two miles from the Cueva del Valle del Marqués described above. An entrance pitch of 110’ leads into a large, curved chamber with a sloping rubble floor. This curves downward and narrows until choking about 200’ from and 100’ below the foot of the pitch. A 40’ pitch opposite the entrance pitch drops into a narrow rift which leads into a series of dry caverns, about 50’ high, in which considerable clastic deposition has occurred. After two 25’ pitches, the way on is through a hole blasted in a piece of stal into a very well decorated small chamber. After climbing down a steeply inclined bedding plane and a 50’ pitch, the final chamber is reached. This is curved in shape, 100’ long and about 75’ high, with calcite walls and floor. Above the final pitch, a series of small passages was explored, but these led nowhere. The entrance to the cave occurs in a sloping limestone pavement, and it is hard to see how an active stream ever flowed in through the pitch. The entrance is in Devonian limestone.
Fly Pot:	This is to the west of Cueva de Valporquero and was named after the very large number of flies found at the entrance. It consists of two 50’ pitches and then a short passage following a small stream. This eventually choked in mud and rubble which cannot be dug.

After exhausting the possibilities of the Valporquero area in the first three weeks of the Expedition, there arose the question of what area should then be explored. There were two possibilities, either going to a completely new area and starting with no prior knowledge of the prospects, or returning to the district partially explored by previous expeditions. In the event, it was decided to do the latter, and the Expedition moved to a site near the town of Cangas de Onís, at the north of the Picos de Europa. Most of the caves found there were completely new, although there was one, reported on a previous expedition, which had to be investigated. This was called Jou Cabau, and had been reported as a very large diameter shaft over 150’ deep, high in the mountains to the east of Cangas de Onís. This was found on inspection to consist of a cylindrical shaft, about 150’ in diameter, between 175’ and 200’ deep, filled with 15’ of snow at the bottom. The perimeter of the cylinder on one side riddled was riddled with smaller shafts which were connected at their bases to the bottom of the main shaft. As these were on the uphill side, they probably took most of the surface water in times of heavy rainfall. On the opposite side of the cylinder, a small, well decorated passage led to a thin, but very tall, rift. This was descended in stages, using 175’ of ladder, to a narrow stream passage at right angles to the rift. Upstream probably led back to the bottom of the main shaft, but the way was stopped by a difficult climb. Narrowing of the passage stopped any progress downstream. The total depth of the pot was estimated at 500’.

As found before in this area, the majority of caves consisted of vertical shafts which were found to be blocked at the bottom. Only two caves, apart from the Jou Cabau, were of any interest, Cotozia and Cueva Huelga. The upper series of both of these caves had been explored previously and had been denuded of all of their formations, which we presumed had been taken as decorations. The Expedition penetrated further than earlier parties.

Cotozia:

West of the Sella gorge, near the village of Belaño. The entrance is a large hole in the side of a small cliff. There is a long daylight chamber, 20’ high and about 75’ long. On the left of this a very narrow squeeze, 10’ long, leads to a series of dry chambers. These are full of very beautiful formations, certainly the best encountered by the Expedition. After three chambers, the way is blocked by a calcited mound of rubble. Two avens were climbed, but these were stopped in the same way. At the base of the rubble, the bones of a large bird were found. As it was impossible to move these without damaging them, only photographs can be used as a means of identification.

Cueva de la Huelga:

The entrance is situated in an orchard near Nieda, east of Cangas de Onís. There was a small stream flowing into the cave, but debris high on the walls indicates that, in times of heavy rainfall, a considerable torrent may flow into the system. The upper series is complex and extensive and at one time may have contained a lot of formations. Two routes may be followed into the rest of the cave, one down a 50’ pitch near the entrance over a large pool, the other a dry crawl in a series of sandy passages extending from the upper series. These both lead into a continuation of the main stream passage. This continues, with a number of blind side passages, into two large chambers. From the second of these, a winding passage leads into a bedding plane. At the bottom of this a small phreatic passage stops where the stream is met again. This disappears in a narrow sump, which would be difficult to dive. Nearer the entrance a dig in mud was attempted to locate the stream but this had to be abandoned due to lack of time.

This concludes the description of the cave explored, as the others met with do not merit attention in an article of this short length. Surveys of the following caves were made, and should be available when the Expedition report is published :- Cueva de Valporquero ( as this was drawn p by the Spaniards, its accuracy may be open to some doubt ), Sil de la Columbina ( Ghyrrt Cavern ), Fly Pot, Cotozia, and Cueva de la Huelga.

A conclusion on the success of the Expedition must also be left to the official report, but my personal opinion would be that the Expedition was made too large and too strong on the basis of the reports by the Spaniards. As these reports proved to be very unreliable, the full potential of the Expedition was never realised in the caves that were found. The pre-Expedition organisation was good and, given some very extensive systems to explore, it could have been far more of a success than it was.