The Stream-Bed Of Fell Beck Above Gaping Ghyll

By Harold Brodrick.

Fell Beck flows down Ingleborough through a large basin of glacial drift, and at a distance of about 400 ft. above Gaping Ghyll receives from the right its last lateral branch, (Thack Pot Sike), which has cut a deep gorge in the drift. Immediately below this point the stream-bed becomes much wider, (say 50 ft.), and the stream spreads into several channels, of which only that on the left carries water under normal conditions. Here the stream, which has hitherto run about W., turns due S. after a fall of some 3 ft., and for the first time flows over the bed-limestone.

At this point, and under the right bank, is the first sink (P. 1a, not shewn on the Plan), the water sinking into an E. and W. fissure in the stream-bed, about 2 ft. long and l in. wide, with a greater width under the bank. Other very small fissures running N. also take water. This sink seems capable of taking nearly half the normal flow.^[1] From P. 1a the stream-bed runs S. for 76 ft., falling on the way over one ledge, 2 ft. high, into a pool, but without any sinks, so far as present observation has gone. The stream-bed is entirely composed of bed-rock limestone as far as the line opposite P. 1, where it drops nearly 3 ft. and is covered across its width with glacial stones. There is probably a fissure across the stream-bed at this point. Close to the left bank is the Camp Sink (P. 1 which, when opened, i.e., cleared of stones and sand, is capable of taking the greater part of the normal flow of water, which water reappears at the Spout Tunnel.

At P. 1 the stream-bed turns W. and is much crevassed. Normally the stream flows on the right-hand side, but can be diverted into the sinks P. 2 and P. 3 and thus into the Spout Tunnel. The stream when coloured at P. 3 reappears at the sink P. 4 only to sink again at once and not show again on the surface.

After leaving P. 3 there is a step of 3 ft. in the streambed, with several big boulders on the low side. Close under this step, on the left, are three sinks, (P. 4, P. 5 and P. 6), into which some of the water flowing over the step normally sinks. If a considerable stream is turned into these sinks some of it comes out at the point S.2, and flows over the lip of Gaping Ghyll, but the low-water flow down the sink P. 4 runs in some other direction, probably into the Spout Tunnel. Close to the opposite or right bank is a big sink in the stream-bed, the Rat Hole Sink, (P. 14), which can take a normal flow of water. This water can be heard at another fissure in the side of the bank a few feet below P. 14, and then flows down the lateral branch of the Rat Hole.

At a point 42 ft. lower down and still on the right hand bank of the stream-bed is the entrance to the Rat Hole which was first noticed in 1909. As this opening was found to be capable of taking the very large stream of water which in times of flood falls into the Great Chamber of Gaping Ghyll at some distance from the Main Waterfall and Spout Waterfall, a dam was constructed across the stream-bed at this point. Holes, about 3 in. deep, were laboriously drilled into the flat limestone bed of the stream, steel uprights leaded into them, and four planks fitted with iron D’s so as to allow of being slipped on to the steel uprights; thus forming a dam capable of turning a 2 ft. head of water into the Rat Hole. At the ends of the planks, next the banks of the stream, any openings in the rock were cemented up, and now, with the help of a few sods, practically no water can get further down the stream-bed except in times of excessive flood.

At the E. end of the Dam, i.e., at the end furthest away from the Rat Hole, is a sink, (P. 15), in the stream-bed capable of taking about half the normal flow, the greater part of which after running close under the surface appears at the point S. 3 immediately above the Windlass Platform, and flows over the lip of Gaping Ghyll.

A few feet below the Dam is a long sink, (P. 7),nearly filled with pebbles, which communicates with the point S. 1 a few feet below it and at the end of the bed in which it lies.

Below P. 7 the stream, in several places, runs for a few feet under thin beds of rock, but nothing of any importance is met with until we arrive below the drop above the Windlass Platform. This drop is over a shelf of limestone, some 6 ft. in height, with a sink, (P. 11), immediately above it on the left. The water of this sink reappears below at the point S. 3, only to fall over into the Main Shaft. At the other or right-hand side of the stream-bed, and above the shelf, is another sink, (P. 12), the water of which reappears below the shelf, part of it in a small cave (T), which was, until Whitsun, 1912, blocked up, the remainder flowing underground to find its way into the upper end of the Jib Tunnel. At Whitsun, 1912, the block of rock which obstructed the entrance to T was hauled out and Wingfield was able to crawl in about 6 ft. The cave continues forward but is too small to admit of passage until several stalagmite bosses have been cut away, no easy matter in such a confined space.

Below the Windlass Platform there is a further drop of 5 ft. on to the broad slab, the further edge of which forms the actual lip of Gaping Ghyll.

I now propose to describe the various high-level passages so far as they are known at present.

The Rat Hole. When first observed in 1909 (Y. R. C. J., vol. III, p. 186), this passage could not be entered until a block of limestone which obstructed the mouth had been removed, and even now the actual opening is still divided into two by a partition of rock, the easier passage being on the right-hand.^[2] A crawl round an S bend leads into a straight circular pipe, 2 ft. high and of about the same width, which continues for a distance of 18 ft. as far as A, where, although the roof is still no higher, the right-hand wall opens out into a low bedding-cave, some 10 ft. wide and 7ft. long, where it is possible to turn round. After this the passage resumes its former drain-pipe character for about 26 ft. as far as B, and then becomes slightly higher, the slope of the floor dropping rather more rapidly than that of the roof . At B a stream comes in on the right from another still smaller pipe which up to the present has not been explored.

As far as B there is no running water in the passage under ordinary conditions, but numerous shallow pools in the floor. At the time of the first exploration there were also numerous banks of sand and stones which added considerably to the difficulties. Some of the larger stones have now been wedged into a low bed which occurs in places near the roof, and the flush of water from the stream has washed the sand and smaller stones down the pipe.

Immediately beyond B is a drop of about 18 in. into a pool of water about 1 ft. deep and the passage for a few yards becomes comparatively large, being about 4 ft. high, but it soon becomes lower again, and after crawling over a very uneven floor the second bedding-cave is reached at C. Here the stream turns at right-angles to the left for 6 ft. and then, at D, forms a slender waterfall of about 8 ft. To negotiate this fall it is necessary to crawl to the right until one’s legs are out of the main-passage and then crawl backwards to the top of the drop. The climb down is fairly easy, and, as one is already thoroughly wet, the additional discomfort is not noticed. At the bottom of this fall – 85 ft. from daylight – it is possible for the first time to stand upright, as the roof is some 10 ft. high. From D the passage continues very low and winding for about 15 ft. and then becomes high enough to allow of walking sideways, but with a steepening gradient, as far as the junction at E.

At the Junction the stream from the Rat Hole Sink (P. 14), joins the main-passage, and on one occasion, when about half the normal surface-flow of Fell Beck had been turned down P. 14 it entirely prevented any further investigations beyond this point.

From the Junction, (E), the passage, at this point about 6 ft. high, becomes rapidly higher, with the stream running over a series of steep water-slides, until, at 15 ft. from the Junction, the lip of the Fourteen Foot Pot is reached at F. The stream itself falls over the lip, but it is possible to climb round and upwards to the left over a tufa-covered slope and on to a saddle on the far side of the pot. The far side of this saddle is covered with loose stones and slopes steeply for about 8 ft., beyond which there seems to be a sheer drop to the bottom of Gaping Ghyll at G. Any further exploration in this direction will be by no means easy owing to the rotten condition of the saddle and the difficulty of getting ladders so far.

With care the pitch into the Fourteen Foot Pot can be climbed. The first descent was made by Wingfield with a life-line; and after he had climbed back the rest of the party went down, Wingfield following. The Fourteen Foot Pot consists of an oblong chamber, some 10 ft. in width. The stream flows over the stones which compose the floor and away to the right down a fissure passage. This passage is about 5 ft. high at first but rapidly rises in height while the stream falls rapidly for about 15 ft. and then takes its final leap into the unknown at H. A large gritstone boulder near the commencement of the fissure forms a bridge which affords an excellent belay. The left hand floor of the fissure is missing, but along the right hand wall is a ledge about 1 ft. wide which offers a passage to the end of the fissure, some 20 ft. beyond the boulder. At Whitsuntide, 1912, Wingfield got to the end of this ledge and lowered an acetylene lamp down the shaft and it kept alight for a depth of 50 ft., showing up details of the grooved walls of the shaft. This shaft is at least 30 ft. wide, but we found it quite impossible to estimate its depth. We lowered a plumb line but could not get it to descend beyond a ledge 200 ft. below us. This ledge is approximately at the level of the ledge in the Main Shaft of Gaping Ghyll and of another ledge visible from the boatswain’s chair near the roof of the Great Chamber. It does not seem unlikely that there is a hard stratum of limestone here, and that, if a descent from the end of the Rat Hole could be made, an entirely fresh system of caves might be found at this level.

I have already mentioned that at the Junction, (E), shortly before reaching the Fourteen Foot Pot, there is a stream flowing in from a passage on the left. This passage at first is about 5 ft. high and 2 ft. 6 in. wide, but after passing up-stream for about 25 ft. the roof lowers to about 3 ft. at K, and about 20 ft. further on widens out into a bedding-cave at L, but, after about 10ft., again contracts, and resumes the ordinary narrow stream-passage type, with the roof about 3 ft. above the floor. At a distance of 40 ft. from the bedding-cave the roof is about 2 ft. 6 in. above the floor and the passage extremely narrow, the direct passage being entirely blocked with boulders which have fallen from the roof, but it is possible to work round these to the left, and then through them into a circular chamber, (the Waterfall Chamber), some 9 ft. high and 10ft. across, at M. The stream falls into this Waterfall Chamber through a fissure and forms a waterfall 6 ft. high, but, unfortunately, the fissure is too narrow to get through. The main passage to the left of, and under, this waterfall spreads out into a wide bedding-cave, too low to admit of exploration. Fresh grass and numerous live flies were met with here.

The whole of the Rat Hole has been surveyed as carefully as the nature of the place would permit, and it is clear that the lateral branch just described passes under the main passage of the Rat Hole near its commencement at a depth of about 15 ft. below it, and that the Waterfall Chamber is very close indeed to, but about 15 ft. below, the Rat Hole Sink, (P. 14), from which it is fed.

The Jib Tunnel, which is too well known to require any detailed description, consists of a straight horizontal passage, some 5 ft. high and 15 ft. long, leading from behind a big block of limestone to the top of what is, in wet weather, the highest waterfall in the British Isles.

The Spout Tunnel At the end of the Whitsuntide Camp, 1910, Booth and Wingfield succeeded with the aid of the boatswain’s chair and of a rope-ladder, which was hung from the jib-end at the far end of the Jib Tunnel, in getting into the mouth of the Spout Tunnel. A few weeks later a full exploration and survey was undertaken, (Y.R.C.J., Vol. III, page 190).

The floor of the passage drops very rapidly in the first 10 ft., and getting into it from a ladder fastened inside is by no means easy. About 20 ft. from the entrance a small stream flows in on the left, from a passage about 6 ft. in height, which after 10 ft. is blocked up by a mass of boulders that completely stops any further advance. Beyond this point the main-passage continues, with a height varying from 4 ft. to 8 ft., for 130 ft. as far as the Junction Chamber, at N. At one part is a fissure at least 20 ft. high, too narrow to admit of climbing. The strata to the N. of this fissure seem to dip S. at an angle of 48°, and it is a curious fact that the same dip is seen on the S. side of the Fourteen Foot Pot in the Rat Hole and also in the photograph of Gaping Ghyll, facing p. 233 in Y.R.C.J., Vol. III. It is very probable that this dislocation of the strata is closely connected with the formation of the Main Shaft and the Great Chamber of Gaping Ghyll, and that this great natural wonder owes its origin to a fault, the existence of which has only recently been realized.

After the first 10 ft., and as far as the Junction, the Passage is for the most part about 3 ft. wide, of the usual stream-passage character and practically level. At one place is a waterfall about 3 ft. high. The junction, (N.), is a triangular chamber, at the apex of which the main-stream enters down a waterfall, 30 ft. high, but beyond the chamber the main-passage continues for 75 ft. to the point P., in a straight line, and with a height of 3 ft. diminishing gradually to 2 ft. In this length is a very high fissure in the roof similar to that in the earlier part of the passage. At the end of this passage the roof rises to a height of at least 20 ft. and slight waterfalls come in on the left, the first about 12 ft. and the second, about 8 ft. further on, 10 ft in height . Both of these can be climbed and both are fed by the same trickle of water from a passage some 20 ft. above, (at Q). It will be quite impossible to climb into and explore this passage until a ladder is taken in. This point Q is found by survey to be almost directly under the sign-post which stands above the shake-hole of Gaping Ghyll, and it is nearly certain that the water met with at Q is supplied from the swampy ground on the surface, as it was found to be exceedingly cold, whilst that which fell into the Junction Chamber, (N), from the high-level passage (see below) was very warm. The stream temperature of Fell Beck at the time was 6o°, so it is clear that the high-level stream must be fed from a direct stream and the low-level stream by percolating water.

To return now to the Junction Chamber, (N). When the Spout Tunnel was first explored it was found impossible to climb up the waterfall, owing to the quantity of water, but on the second visit Wingfield managed to climb up the pitch in the full course of the waterfall. Booth and Davidson followed and the three then completed the exploration, of which the following is Wingfield’s description:-

“The lower of the two pitches consists of a nearly right-angled chimney, divided at the bottom by a leaf or knife-edge of waterworn limestone. The climb commences from the top of the knife-edge and continues for a height of about 30 ft. through the full force of the waterfall, which under favourable circumstances would pass through a 4 in. pipe. Two horizontal cracks about 12 ft. above the pool at the bottom give an opportunity for a rest and change of position, and from here to the top of the fall the handholds, many of which are very rotten, have to be found by touch alone, as the lights below are of very little assistance.

At the top of the lower pitch is a small chamber about 10 ft. high and 8 ft. wide, from the far side of which the stream falls out of a stream-tunnel some 10 ft. above the top of the lower pitch. The climbing of this upper pitch is comparatively simple and leads into a stream-passage similar to, but, if possible, of slightly less dimensions than the Rat Hole. From here the passage continues for a distance of 160 ft. with one or two inflows of water, the main-stream becoming less and less. At this point, (R), the passage becomes too small to admit of further progress, but water could be heard falling a short distance beyond.

The return from the end of the passage to the top of the Junction Chamber had to be made backwards as there was no room in the passage to turn round. The climb down the two pitches into the Junction Chamber is by no means an easy one, especially for the last man, as, although there are two belays at the top of the lower pitch, one is loose and the other too rounded and slippery to afford much security.”

At R the water was very warm indeed and many land insects were met with. On plotting out this passage the point R was found to lie between the Camp Sink, (P. 1), and P. 2 at a depth of a few feet only below the level of the stream-bed at this point.

In Vol. II., p. 49, of the Y.R.C.J., Cuttriss states it as his opinion that the sinks in the bed of Fell Beck are widening rapidly and that the time may come when the Main Shaft of Gaping Ghyll will be dry. I can fully endorse this view and am of opinion that the action is taking place at an extremely rapid rate. In 1872, Mr. Birkbeck, on the occasion of the first recorded attempt to descend Gaping Ghyll, had a long trench made to carry off the waters of Fell Beck, so as to leave the lip of the Main Shaft dry ; and as late as 1895, M. Martel had this trench repaired and even then was troubled with falling water. At the present time it is only after rain that we have water falling down the Main Shaft, and during the summer months it is dry in normal weather. It is clear that Mr. Birkbeck, a native of the district, would never have gone to the expense of having a trench of such magnitude built if there had been a chance of the lip being dry at any time during the summer. During the last ten years, according to my own observation, the sinks have been taking more and more water each year, and as the upper sinks, (P. 1a, P. 1, P. 2 and P. 3), all feed the Spout Waterfall, there is a danger that the Spout Waterfall may render the present method of descent by windlass from the end of the Jib Tunnel impossible, except in very dry summers, or unless the water is carefully dammed out of these sinks and directed into the Rat Hole Sink and the Rat Hole itself.

Plan Of Fell Beck With The Rat Hole & Spout Tunnel