OUCC Proceedings 1
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Aygill Hole; Bouther Gill Cave
In March 1960, three members of the Club were taking their first look at Lancaster Hole, with a 1946-vintage survey as their guide. In the section beyond the Graveyard and Stump Cavern , not marked on this plan, one of them came across a low crawl which seemed little frequented. He followed it and came to a small stream passage, leading to a pitch which, he decided, had not been descended. However, there was no time to bring in the necessary tackle, and the descent had to be left for the time being.
In March 1961, a much larger party was available, and it was decided to fill in some of the gaps in the 1948 survey, by the British Spelaeological Association, of the Graveyard section. Two parties were formed to do this; the first to look at the continuation of the gully in the Graveyard itself, and the second to investigate the crawl visited the year before. The first party had a good start, and when we (the second party) passed through the Graveyard some four hours later, we could see that they were still at work. At no time did either party see or even hear the other; we went past the gully thinking that the first party must have discovered quite a lot of passage.
At the entrance of the crawl we left some of the tackle we were carrying, and got down onto our stomachs. The crawl was not, however, particularly difficult, though there were one or two low spots; generally it was floored with wet sticky mud. The stream passage too was low where we reached it, but downstream it gained height, until near the pitch it was possible to stand upright. A ladder was rigged on a long belay, and after a tight squeeze in the lowest part of the passage we were able to climb down. Our enthusiasm was quickly tempered, however, by the realisation that we were not the first down; someone had beaten us to it, and very recently too.
From the small chamber at the foot of the ladder a short boulder slope and a climb through a sharp-edged pot led down to a narrow fissure passage. This quickly became a narrow tube, lined with soft black mud, and with a gravel floor; a gloomy place indeed! Beyond a double bend the roof came down to within three or four inches of the floor, but we managed to find a soft spot in the gravel, where we could dig a way through. The effort was hardly worthwhile! A few feet further on was a still dark pool, quietly defying us. A quick dip proved that there was no hope of diving it, as it was very narrow, and our intrepid hydrophiliac, with the water up to his ears, proved that the roof came down uncompromisingly into the water. Rather wet, we withdrew to the foot of the ladder for a breather, noticing on the way a small chamber above and to one side of the passage.
The ladder climb itself is very easy, but it requires quite a struggle to get through the squeeze at the top; one must be very supple and not too large. Leaving the ladder at the entrance of the crawl, we now set off upstream. Here the passage was wider and much higher as far as a right-angled bend where a pile of mud and rock had fallen from an aven; beyond this it became tight again. At another bend, a bedding plane in the roof led away to the left. One of us climbed up to this, but his light went out, and as we were all feeling the cold we decided to return. We made a rapid estimated survey, and on the way through the crawl we measured it with a "stick of known length" -- he was just about six feet long -- and found it to be about 240ft long.
After a short rest we made for the surface, where we heard with interest the report of the other party. They had followed their passage from the Graveyard as far as a pitch, which one of them had descended. He had followed the passage below for a short distance, but had turned back where the roof had become too low. Above the pitch, meanwhile, the others had found a low crawl, which had led them to a series of large passages ending in a deep canal. A strong draught in these passages seemed to indicate that there might be something beyond the canal, and accordingly a party was organised for the following day to survey the passages and if possible to cross the canal.
To make sure that a survey was produced, it was decided to begin at the Graveyard and work inwards; surveys on the return journey result all too often in no survey at all. The trickle of water in the gully passes through a short bedding plane and falls into a high narrow stream passage. We surveyed round several bends as far as the entrance of the crawl, opening on the right-hand side of the stream passage. In the crawl itself surveying was much easier, as we could manage legs of up to thirty feet. We passed one or two low spots, but it wasn't until we reached the end of the crawl that we realised where we were. We had tackled the same passage as on the previous day, from the opposite end, and had failed to recognise it. We knew now, of course, who had beaten us down the pitch, and at least we could put away the surveying equipment.
Despite the knowledge that the passage and the canal were far from new, we pressed on through the boulder choke to the large but muddy passages beyond. These descend steeply to the water, which is very clear and difficult to see. Our resident swimmer embarked on a blown-up inner tube, and floated precariously round the corner, but on the other side of the pool there was only a small inlet passage, completely blocked by a stalagmite flow. A trickle of water hissed down from the roof, eighty feet above, but no other passage was visible.
About halfway back to the "T" junction, however, a small trickle of water was noticed on the left-hand side, and one of the party climbed up to a low bedding plane. This had a floor of very soft mud, except where the trickle had cut a narrow rectangular furrow; marks on the mud showed that someone had been before. After about 50ft. the passage forked, and the previous explorer had turned right. A dig in the soft mud of the left-hand fork gave access to twenty feet more of passage, but when it became necessary to dig our man turned back:- there is just about room to turn -- towards relative comfort. But this must be the muddiest passage in the caving world; the poor bloke got stuck in his own dig, and eventually fell out of the passage, completely plastered with mud, onto the heads of those below. If anyone particularly likes digging through soft mud, he might be encouraged by the draught which blows from this passage, apparently the same one felt in the boulder choke towards Stump Cavern. The mud is similar to that near the sump below the Graveyard. and also covers the walls of the large passage above the canal; it appears to be deposited under water, in which case a rise of at least 50ft. in the level of the canal is indicated.
The survey of the passage below the Graveyard is attached. The Gully in the Graveyard itself is tributary to a narrow stream passage entering from a south-easterly direction, which was not investigated. It has several sharp bends, and it slopes downwards as far as the Mud Aven, which the survey shows to be immediately below the second hollow in the floor of the Graveyard. For a short distance the passage is roomy, with a flat gravel floor and several stalagmite pillars, but the roof drops abruptly to within three feet of the floor close to the junction with the crawl. Beyond this point the small stream has cut a narrow vadose trench in the bottom of a small bedding-plane; this becomes very narrow close to the pitch, which consists of two cylindrical shafts, with fluted sides, opening from the bottom of the passage; the vadose trench continues in the roof. The stream falls down the first shaft, and a dry descent of 25ft. can be made to the flat rock floor. At the far end of this chamber a few blocks have fallen from the roof, but to the left of these is a 10ft climb though two deep cylindrical pebble-scoured basins. Below, a short phreatic tube, with a gravel floor, leads to the terminal sump. The extent of the mud on the walls of this passage suggest that the water here rises no more than 10ft, unlike the canal beyond Stump Cavern.
The crawl consists of a phreatic bedding-plane, from two to six feet wide and one to three feet high; two or three bell-chambers in the roof have apparently been formed by solution under pressure. The passage has been half filled with sand and mud, which had since been partially excavated. In places this mud is covered by a thin calcite floor from which rise small stalagmite pillars, similar to those in Stump Cavern immediately above, and in one of the small chambers there is a large calcite column. The whole passage slopes down towards the stream passage, and may at one time have drained the far end of Stump Cavern.
Lancaster Hole; Bouther Gill Cave; Contents
There were one or two beautiful Spring days in March 1961, when even to hardened 'holers the call of the hills was louder than that of the caves. Thus it happened that a day which could have been spent caving was spent on the surface. But before you condemn this sacrilege. let me say that by evening our consciences were growing uneasy. Just before midnight we succumbed to temptation, and set off to investigate a few shakeholes near Bull Pot Farm.
There was a bright moon, but though we found plenty of shakeholes, but they didn't look particularly interesting, so we wandered of the deep valley of Aygill, to look at the sink there. This is without doubt a hopeless proposition, but close by, under a low cliff, there was a small shaft, and we climbed down. On one side, through a gap in the boulders, a small chamber could be seen, and hopes were high as we dug out the obstructions and at last climbed through. A quick tour of the cave was made; quick because it wasn't very big; and, our consciences salved, we called it a day, or rather a night, and went to bed.
On the following day a survey party was formed to measure up our "find", and we spent several hours pushing into odd corners. The twelve foot shaft leads to a small bedding-plane floored with boulders, with a narrow slit on the lower side through which we had dug the previous evening. This leads into a small chamber, 10ft x 8ft x 5ft, with two passages leading on. In the right-hand corner a smooth narrow inlet passage can be penetrated for about ten feet, after which it becomes very right. The other passage enters a narrow rift, six feet high, which becomes more roomy, and descends in steps to a low crawl and to the final chamber, apparently formed in a mud and gravel deposit which quickly showed its instability. There are three extensions to the cave, all on the left- hand side; coming back from the final chamber, the first is a bedding-plane crawl to an aven, the second a series of holes round a jammed boulder perched on the edge of an eight foot pot, and the third, high up at the end of the high rift, leads to a series of chambers and crawls. The first of these chambers is an aven, eighteen feet high, with three passages leading out; of the two inlet passages, one enters a boulder chamber close to the surface, and it is said that an entrance to the cave can be made here at times. The third passage leads to another boulder chamber with beyond it a very low crawl to a fissure passage, where further progress is blocked by a large rock flake. Beyond this flake the passage drops abruptly and becomes much larger; unfortunately there seems to be no way of passing it, and even if this were possible, from the character of the rest of the cave it is probable that the large passage would be very short. Again, this section is dangerous on account of the boulders which form one side of the passage; the underside of the mass of boulders filling the Aygill valley.
Though this cave is small, with less than 150ft. of passages, it is complex and interesting. It lies close to the Dent Fault, which in this area determines the western limit of the Mountain Limestone block, and is developed in rocks which dip towards the north-west at an angle of 30° , a rare occurrence in this area of predominantly horizontal rocks. Though most of the rock is dark in colour, and the passages are full of sharp edges, the inlet passage in the main chamber is developed in light-coloured rock, and has smooth, water eroded sides. This passage extends downwards, and though a small hole in its floor a chamber cab be seen at a lower level; unfortunately we were able to put a hand through only, and we could not move the boulder which blocks the hole. There are few formations; those near the 8ft. pot have been broken by recent movement of the boulder perched above it.
The stream sinking by the entrance did not appear in the cave, neither is it heard, though it probably flows in the cave in times of flood. Normally it sinks through the deposit of boulders on the valley floor, but as it does not reappear in the Aygill valley, it must flow southwards into Bull Pot and so to Leck Beck Head.
We realise that these visits are by no means the first to the cave, but as we know of no description, or even any mention of its name, we take the liberty of including it here.
Lancaster Hole; Aygill Hole; Contents
Snow on the ground provides an excellent chance of finding cave entrances, which show because the draught melts the snow over the entrance. So Easter Tuesday, 1961, saw two of us looking at sinkholes near Hubberholme, in Wharfedale. We were following Bouther Gill, a small stream which has cut a deep cleft in the southern side of the main valley, when we noticed a sizeable cave entrance at stream level, from which a small stream flowed. As we didn't know of any record of this cave, we clambered across the stream and passed into the warmer atmosphere of the underground.
The cave proved to be quite interesting. The clean-washed stream passage, about six feet high and two feet wide, wound on for some distance, becoming higher and generally narrower after some thirty feet, though not so as to make progress difficult. An 8ft. waterfall provided a sporting climb, and above it the passage continued, now tighter, with correspondingly deeper water, and about ten feet high, with a narrow bedding plane in the roof. A small chamber, its floor under two feet of water, was passed before a deeper pool, with mud floor and a low roof above, made further progress in the clothes we were wearing impracticable. From beyond, however, came the sound of falling water, and we withdrew to don more suitable attire for the swim.
After lunch we trudged through the now deep snow to the cave again. We were soon through the low section, and we found ourselves in a large chamber, about thirty feet long and twenty-five feet high, completely occupied by a deep pool. The stream fell from a narrow fissure in the roof, but there was no possible way on. A little disappointed, we once again withdrew, making a survey as we went.
Below the waterfall the floor is remarkably clean-washed, and above it there are only a few small pebbles, where the rate of water flow is less. The floor of the final chamber is of thick mud, and mud also occurs near this pool, but above water level, in shallow fissures out of reach of the stream.
Near the entrance there is a bluish-white soft deposit, occurring both as a flow and in spherical nodules, and above the waterfall a soft black deposit, occurring once as a roof flow, but more often on the cave walls, was found.
The terminal chamber contains a stalagmite flow, coming from an aven in the roof, and at several points there are straws, some of them 18" long.
Lancaster Hole; Aygill Hole; Bouther Gill Cave
OUCC Proceedings 1 - Contents