Journal Series 3 Number 2

Note that this is a re-print of the original publication, based on a scanned copy. During the process of converting the original paper copy to this electronic version, the original formatting, page layout and page numbers have been lost. All diagrams and surveys have been scanned from the original and are consequently of poor quality.

 

Contents

Exploration of Swildons Six and Discovery of Seven by KR Dawe

Short Duration Diving on Air by JM Boon

Banging in Trouble Series by KR Dawe and FJ Davies

Carricknacoppan Caves by MM Thompson and JM Boon

 

Journal published by the Shepton Mallet Caving Club

The Mineries, Wells Road, Priddy, Wells, Somerset, BA5 3AU

http://www.shepton.org.uk

 

Editorial

Once again we seem to be able to produce on edition devoted to reports of original exploration, and the techniques used.

Some club members may be dismayed by the emphasis there seems to be upon diving, and this is a disease that is spreading rapidly through the club. Yet surely it is axiomatic that an active stream passage, sooner or later, sumps. Diving is the most powerful tool yet developed to force a sump and if we wish to continue the exploration of such passages it appears we must dive. Diving should be looked upon as another technique used by cavers to overcome an obstacle just as a ladder is used to pass a vertical descent. It must be realised, however, that the safe use of diving equipment requires considerably more training than does the use of caving ladders.

Neither must it be thought that this is now the only way to discover new cave. Mike Thompson has recently reminded us of the strength of more traditional methods by digging an entry into a new cave system close to Downhead. At the time of writing it is only about 150 feet in length but hopes of reaching on extension are high and we hope to publish a report on this work in our next journal.

 

The Exploration of Swildons Six and Discovery of Seven

Introduction

The recent downstream extensions in Swildons Hole follow as a direct result of the discovery of Swildons Four by the Westminster Speleological Group in the summer of 1957. Swildons Four contains about 900 feet of streamway with a sump at either end. As the upstream sump is expected to lead very quickly to the bell chamber complex comprising Swildons Three (the survey by WI Stanton shows them separated by a mere 50 feet) it has been more or less ignored.

Many attempts were made to force the lower sump and so reach a downstream extension. These efforts, mainly by the WSG, failed but on 13 September 1958, Oliver Wells and John Buxton of the Cave Diving Group successfully passed the sump. Len Dawes safely followed the divers without breathing apparatus when it was found that the sump was only of the order of 20 feet in length. The sump is now regularly passed in a free dive but should only be attempted by experienced and confident swimmers.

The passage so reached, Swildons Five, led via 300 feet of wet passage with little airspace to Sump Five. This was attacked by Oliver Wells, this time with Phil Davies in support, in the November of 1958. A sump reported as 60 feet in length was passed by Wells, but as the oxygen equipment of his support had been damaged on the journey into the cave he made no attempt to explore the passage, Swildons Six, so entered.

He did, however, make a close examination of the downstream end of the sump and formed the opinion that the sump was formed by water being held back behind a large bank of silt and gravel. This bank he considered could be dug away by a large enough team of divers and so make Swildons Six accessible to non-divers. An attempt to do this was made in January 1959 but rising flood water due to heavy surface rain defeated the party. At this point, Oliver Wells took an appointment in the USA and the direct downstream exploration of the cave ground to a halt. There were not enough divers with a love of Swildons.

Attention now turned to Priddy Green. This had been proved to connect directly with Swildons Four and we hoped to push the connection and so provide an easy route into the diving site. Unfortunately, despite a tremendous effort this stopped far short of Swildons Four. It is still worth digging for its own sake, but the present end is a ghastly solid choke.

The next point of attack was at Shatter Pot in the St. Pauls Series of Swildons. It was hoped that this might have led directly into Swildons Six, or beyond. Several months of hard work led to 300 feet of cave, the end of which was scarcely one inch closer to Six than the beginning.

A fuller report of these activities are to be found in the journals of the Westminster Speleological Group, Wessex Cave Club, and SMCC, covering the period 1957 - 1961, and, with the exception of Shatter Passage, the discoveries are recorded on the latest edition of the survey by WI Stanton.

The Opening of Swildons Six

By early 1961, Mike Thompson, Jerry Wright and I had all completed preliminary Cave Diving Group training and were deemed competent to dive in the presence of a more experienced diver. Mike Boon had designed, acquired and become competent in the use of a compressed air kit of his own, and Phil Davies of Wessex readily agreed to throw his greater diving experience into the fray. Having assembled a diving team we chose Saturday 17 June as the date of our attempt to enter Swildons Six and remove the sandbank.

During the early months of 1961 a large amount of equipment of every sort had to be carried into the further reaches of Swildons Hole. Primus stoves and fuel, cooking pots and food, ropes, digging tools of all types (try taking a full size pick and shovel down Blue Pencil Passage), over one hundred pounds weight of lead, and telephones and line to provide communication between Four, Five and Six. In this we were given a great deal of willing assistance by cavers, too numerous to name, who could not be included in the main trip, but it was their willing assistance that made the trip possible.

At last the day of the operation arrived, Bob Pyke (Wessex) and Fred Davies were first into the cave at 08:40 hours, carrying the perishable items of food and, as important to the diving team, cigarettes. Mikes Boon and Thompson and I followed about half an hour later carrying only our individual diving gear, whilst Jerry Wright and Phil Davies, similarly loaded, came fifteen minutes behind us.

Once at the base in Four we divers assembled and checked our breathing apparatus while Bob and Fred prepared a hot drink for us. Mike Thompson and I went into Five, Mike breathing from his set but I freed dived through wearing a set in order to conserve gas supplies. We carried a telephone with us and this was quickly hooked up to a line laid the previous week. At 14:30 hours we at Sump Five were in contact with the base at Four. We asked them to send through a spare face mask glass as Mike had lost his somewhere in Swildons Five and learnt that there was some delay due to Phil finding a tear in the hood of his suit. Meanwhile Jerry and Mike Boon passed Sump Four and the remaining equipment was hauled through on a line and carried through Swildons Five to the mud bank this side of Sump Five.

As both Mike Thompson and Phil Davies had been troubled by leaking suits we decided that they should go first into Swildons Six where, finished with underwater work for a while, they could strip and wring out soaked clothing. At 16:00 hours Mike slipped into the water dragging the end of the telephone line with him and was followed a few minutes later by Phil carrying the phone. It was not long before we had all three parties in communication with each other and Mike Boon was on his way to join the other Mike and Phil in Six. Boon carried the end of a rope which was then used to drag the remaining gear, digging tools and food through into Six. Fortunately the sump proved to be straight as an arrow and so this manoeuvre was easily accomplished. With all the kit gone through to Six Jerry and I signed off from the phone in Five and dived in tandem. I was amazed by the ease and shortness of the sump, one breath and head emerged into a small bell chamber, another breath and I was above water in Six.

The prospect was most disheartening and at that moment I never really thought that we would break the sump. I afterwards found that all the others had felt the same, but we had, before entering the cave, agreed not to explore until we had made a real effort to lower the sump. So although without hope, we set to work.

A huge bank of sand and gravel, 20 to 30 feet long held back the water and it was necessary to excavate a canal about two feet deep over the whole of this distance. We worked in relays, those resting smoking and brewing tea or soup at the advance kitchen we had set up.

After a couple of hours work we were surprised to find that the water level had dropped appreciably. Suddenly, as Jerry and I worked close by the sump we heard the welcome glooping sound of the water sucking and gurgling against a roof close above it. We literally threw ourselves into the task and within ten minutes the sump was raising a whole symphony of gloops. Then the noise suddenly died; dare we hope that a practical airspace existed over the sump? Jerry and I investigated, and found it quite easy to return as far as the erstwhile bell chamber, roughly half way. Beyond this the roof still sumped. We returned to our digging.

The water level was now visibly dropping and Mike Boon decided to have a crack at returning to Five. I accompanied him as far as the site of the bell chamber to provide extra light. A low airspace meandered gently upstream and Mike edged gently into it; it was very tricky going. Suddenly a tremendous Boonian bellow rent the air, he had reached Swildons Five without breathing apparatus. I shouted the news to the digging team.

When sanity was restored the news was passed to Bob and Fred in Four and we learnt that our support party of Dave Causer (Wessex), Neal Cleave (Wessex), Frank Darbon (BEC) and Steve Wynne-Roberts had recently arrived in Swildons Four and so were to join us at the earliest possible time. It took them only twenty minutes to travel from Four, through Sump Four and the low canal that now took the place of Sump Five, to Swildons Six.

The support party took over the digging, we intended to get the water as low as possible, and after a short rest the divers set out to explore the new cave.

For eighty feet the stream ran roughly North East, the passage was large, 25 feet high in places, then the passage turned round to the right until it was travelling almost South West and the roof dropped to four or five feet, forcing us to crouch as we passed beside a high bank of mud. Another sharp turn, to the left, and we were travelling North West again for 100 feet, then right into a ten feet high rift which led after thirty feet to the inevitable sump. Sump Six, now seen for the first time, looked most unpromising, a dark pool of scummy water, 20 feet long and 6 wide with a tremendous collection of old candles floating on its surface. We paddled around in it for a while but could only discover that the water was deep, two paces from the edge and we were forced to swim. We started to retrace our steps, but Boon immediately disappeared up a small aven on the right (north) side of the streamway. He reported a few feet of passage leading to a small pot. The support party later managed to descend this pot but could find no way on and Steve Wynne-Roberts found a further 150 feet of passage at the top of the aven but leading away from the pot.

At our advance kitchen, just downstream of Sump Five, a small tributary entered from the North East. I went up this for a short way, but after 40 feet it was so narrow and muddy I decided to leave it to the fresher support party. Dave Causer later forced his way for 100 feet up this partly mud filled tube to an apparently impenetrable sump. The survey made later by Derek Ford does not indicate that this water comes from any known part of Swildons Hole and it appears most unlikely that it would prove to be the Shatter Passage stream.

At this point the diving party left the exploration of Six to the support team and returned to the base in Four. I was amazed at the way our digging had lowered the water level in Five. The ducks had all disappeared and even Buxtons Horror, previously a most dangerous obstacle, now had almost a foot of airspace through it.

After a meal and cigarette at Fred's kitchen we started on the long drag out of the cave. We stopped to describe Six to Oliver Lloyd who, accompanied by two UBSS members, was setting up a kitchen in Four to provide a meal for our support team. We finally left Swildons Four just after midnight and the trip to the surface took considerably longer than usual.

Over a huge meal and pint (we seem to have done a tremendous amount of eating) at Ashen Hill Cottage we discussed the next attack. Previously we had agreed to remove all perishable items of equipment on July 8 but it now seemed a better plan to first use the remaining gas supplies on a probe of Sump Six.

Discovery of Swildons Seven

09:00 hours Saturday 8 July saw Mikes Thompson and Boon and I entering the cave. Close behind us came Derek Ford (Wessex), Bob Pyke and Steve Wynne-Roberts. The other members of our previous successful expedition were for various reasons unable to be with us but our team was strong enough for the probe of the sump we had planned. As the whole party was going to Six telephones were unnecessary, we did not intend doing any digging and so the trip would be shorter and make large catering arrangements also unnecessary.

Six was reached fairly easily and whilst we three divers prepared our gear the other members of the party made an accurate survey of Six.

The prospect looked far from inviting. Mike Thompson decided to have a kick around in the sump without apparatus and found it to be about nine feet deep at the further end. He then used his breathing apparatus to examine the right hand wall. We had thought this to be the way on but Mike found no sign of a passage. At the far left hand end of the sump, and a good eight feet under water, Mike felt the beginning of a low slit. At this stage he was forced to withdraw from the water. One of his cylinders had accidentally turned on during transport through the cave and he was now short of oxygen.

I had the next dive and was able to confirm that no negotiable passage existed in the right hand wall. Mike then led to the point at which he thought the slit started. He floated on the surface of the pool and led me by the safety rope to what I discovered to be about five feet wide and two in height. Feeling carefully in the darkness I pushed feet first into this opening and found no obstacle in the six feet or so that I went in. My oxygen was also now getting short so I returned to land and made my report.

Mike Boon using his air kit now took over. He was led to the slot and after one or two false starts entered it and made rapid progress until he had taken the full length of life line. He then remained stationary long enough to get us worried before starting back towards us. Eventually, with a roar like some prehistoric monster he surfaced.

He had reached Swildons Seven.

Unfortunately, when in Seven he was completely at the end of the rope and could not even get out of the water. He reported a passage high enough to stand in with the sound of running water coming from ahead.

The total length of line out was 55 feet and allowing for the sump pools it would appear to be a sump in the region of thirty feet long and at a depth of eight feet. Obviously not to be attempted as a free dive. An attempt to enter and explore Seven during August was called off due to bad weather.

Figure 1 – Swildons Six Survey

Figure 1 – Swildons Six Survey

Conclusion

The exploration of Swildons Six and the discovery of Seven were significant events, not only because of the discoveries made but because, for the first time, a major diving operation involving several divers had taken place at the end of a long and arduous system without the vast army of sherpas considered necessary in earlier operations. Each diver took his own equipment into the cave without assistance. When the five divers entered the water on 17 June the support party present was only two strong. It is true that vast quantities of equipment had been previously cached in the cave, but the bulk of this, digging and telephonic apparatus, is hardly part of normal diving equipment.

Having a small and compact party removed the tremendous burden of raising a large enough team but the principal advantage lay in the fact that all members of the team were friends and caving regularly together. This gave everyone a great feeling of confidence, increased cooperation between the members, and eliminated the possible existence of a weak link.

A further important factor was the splendid catering arrangements. I have the greatest admiration for the way Bob and Fred simply sat by a telephone in Swildons Four, keeping a log of the operation and cooking food at exactly the right moment.

Hopes for the future in Swildons run high. The first project is to enter and survey Seven. The survey should point to any possibility of bypassing Sump Six and so make an assault on Sump Seven, wherever and when found, an easier proposition.

KR Dawe

September 1961

 

Short Duration Diving on Air

This article describes 'Nyphargus', an air breathing set designed for lightweight, or, more strictly short duration, diving and some of its applications. Nyphargus results from an attempt to combine the advantages of oxygen equipment; portability, compactness, and duration, with those of air; mechanical reliability and physiological preferability. It is intended for use in sumps up to 100 feet long and 20 feet deep by a diver wearing an exposure suit and equipped with an electric signalling device. Its duration depends upon the physiology, psychology, and degree of training of the diver, the amount of exertion, water temperature, depth and other factors. Hence it is difficult to quote set figures for the duration, especially as data obtained on actual cave dives is as yet slight, but at a depth of eight feet with a bottom walking diver a cylinder pumped to a pressure of 2500 pounds per square inch might be expected to last 25 to 30 minutes.

The kit consists of a 25 cubic feet bottle (that is one which when pumped to a pressure of 1800 pounds per square inch contains the equivalent of 25 cubic feet at atmospheric pressure) mounted on the right side of the body and attached by a harness of webbing straps. Air is provided by a 'Scubair' demand valve, a two stage valve with the first (pressure reducing) stage mounted on the bottle and feeding via a high pressure hose to the second (demand) stage attached to the mouth piece. A separate face mask covering eyes and nose only is used. The normal method of ballasting is by lead weights carried around the waist.

The 'Scubair' is a strong, well engineered valve which supplies air very freely and is in most respects ideal for the kit. As an alternative the 'Scuba' or Namrod 'Snark' could be used. All these valves are of American origin and obtainable from ET Skinner & Co Ltd of London. The prices being £19, £13 15s and £10 5s respectively. The 'Normalair' single stage demand valve fitted to a separate mouth piece is a fourth possibility. The 'Normalair' full face mask is not advised as it has no gag and so drowning might result from the tearing of the rubber or cracking of the faceplate. The 'Normalair' is made of nylon, is unbreakable, and probably works well in gritty conditions. A disadvantage is that it supplies air so freely that consumption is inclined to be on the high side. The valve costs £4 10s but the adapter would have to be specially made.

For protection on the carry-in the valve assemblies should be fitted into hollowed out balsa wood blocks and carried in an ex-WD ammunition tin. Whilst diving light plastic bags could be tied over the valves to prevent the entry of mud and grit. The high pressure hose can be bound with adhesive tape to give protection from abrasion.

The cylinder used is a straight ex-RAF oxygen bottle of 25 cubic feet capacity fitted with a standard pillar valve giving it an overall length of eighteen inches and circumference of twenty-two inches. It should be tested every four years, an exploding bottle can be most alarming. The pillar valve is protected on the carry-in by a block of wood fitting tightly onto the neck of the cylinder and preventing the valve from being accidentally opened. When the bottle is not actually in use it should always be protected by this block. An alternative system in which a brass thread is clamped onto the neck of the cylinder (heat must NOT be used) and a metal cap then screws onto this thread in being considered. The bottle should be well painted before going underground but really requires more protection than this as 100 yards of crawling will remove all the paint. The requisite protection is probably best given by a tight fitting canvas cover permanently fitted to the bottle. The metal clamps of the harness would then fit over the canvas jacket and so keep it in place. Such ex-RAF cylinders could be purchased for about £5 but are becoming difficult to find.

The harness consists of two bolts riveted onto metal bands which clamp around the bottle so holding against the right side of the body. One belt is worn around the upper chest just below the armpits, the other around the waist. There are two straps passing over the shoulders to prevent the upper strap slipping down. Bottle and harness can be carried into the cave as one unit. The harness should cost little or nothing to make.

Of the other items of equipment the mask is most important. This forms a watertight seal over eyes and nose only and is fastened by a single strap passing over the back of the head. The window should be of shatter proof glass or perspex and a spare carried. No noseclip is used with the kit. The mask is best carried into the cave in an ammunition tin. A pressure gauge is a useful addition to the outfit, it can either screw directly onto the bottle allowing the pressure to be read at the beginning of each dive, or, preferably, be incorporated into the valve assembly so that bottle pressure is known throughout the dive. For protection on the carry in the gauge can also be fitted into a hollowed balsa wood block and carried in a strong can. The price of a mask is about 30 shillings and the pressure gauge about 50 shillings. A knife, in a sheath on the belt and wire cutters on a lanyard, would be useful accessories.

The weight belt used so far is a standard army belt with the back buckles removed, it is fastened by a loop of cord passed through the two doubled ends. The writer uses six 4½ pound leads lashed to the belt. (The exact amount needed varies from individual to individual depending upon physical build and clothing). This is made easier by two holes, the width of the belt apart, drilled laterally through the blocks. A preferable alternative would be to fabricate a belt incorporating pouches to hold the lead blocks. An exposure suit, naval neck seal pattern, is the ideal protection from wet and cold but protection is also needed for the hood and neck. The cheapest way of achieving this is to make a hood from the expanded neoprene sheets obtainable from suppliers of aqualung equipment. The cost can be as little as 10 shillings.

With regard to the techniques of diving on air, the tests of the British Sub Aqua Club will build up confidence and skill in using the kit. These tests include the fitting of the breathing apparatus in 8 feet of water, sharing it with another swimmer, and using it without the mask. The most vital technique is that of clearing the mask. To do this the diver rolls onto his back, or tilts his head to one side, pushes against the top edge of his mask with a hand and exhales strongly through the nose. The use of a noseclip makes this a difficult operation and so the diver must be confident of his ability to breathe through the mouth whilst the nose is exposed to the water.

The duration of the set depends a great deal on the divers economy of breathing, but cold and fear will increase consumption. The British Sub Aqua Club recommends slow deep breathing as an economical method. Other schools of thought advocate a slow inhalation followed by a sharp exhalation, or momentary pauses between inhalation and exhalation. It is probably unwise for a diver to attempt to adopt a forced, unnatural breathing pattern as he will revert to his own natural pattern in times of stress or absorption anyway. It is up to the individual to find his own economical rhythm.

Nyphargus is designed for bottom walking rather than fin swimming on the grounds of greater economy of air consumption and less fear of getting lost. A miners cap lamp with the accumulator worn at the wrist is useful lighting. A good system of communication would be a buzzer at base operated by a switch at the end of a 100 foot long lead so enabling the diver to signal to base when under water. If the lead were fitted with plugs and sockets at the ends then, at a prearranged signal, the switch and buzzer units could be exchanged for sound powered microphones and speech communication established if the diver reached an airspace. Although with this system the diver would be paying out his own line and so be self sufficient, as an additional safeguard he could have a lifeline paid out by base tied to his arm by a quick release system.

Nyphargus was used to pass Sump Five and Sump Six in Swildons Hole during the summer of 1961. It is compact, probably the most compact self contained kit yet developed for cave diving. Its duration is reasonable, far more than is needed to pass many sumps up to 100 feet in length. (After using the same bottle on both Swildons dives it was only half emptied.) Furthermore, as a breathing drill is completely unnecessary when using air, advantage can thus be taken of any small airspace encountered during the course of a dive. With regard to portability the lightweight oxygen equipment has an advantage, Nyphargus makes at least two packs, the valve and gauge assembly and the cylinder. The bottle is the larger load but as this weighs 16½ pounds it can be seen to be a feasible load even in an arduous cave.

The kit seems at its best in a succession of short sumps such as are found in lower reaches of Swildons Hole. Its range could be greatly extended by taking down a second bottle to be towed through the sumps and carried along the intervening passages. Thus the diver could tackle say half a dozen short sumps and then return on the second bottle. And why not fit a demand valve on the second bottle so that at all times a complete spare kit is available?

In the light of my experience with this breathing apparatus I would suggest the following training programme as necessary to bring a diver to a safe operational standard. It is based upon the schedules of the Watford Underwater Club and the Cave Diving Group (as published in British Caving).

Training Schedule

Five hours in not less than five dips in kit intended for use in the cave.

  1. Examine, dismantle and assemble respirator.

  2. Use respirator on land, running and walking.

  3. Dive in chosen dress and respirator.

  4. Eject, and replace mouthpiece three times.

  5. Flood and clear mask (without noseclip) three times.

  6. Remove, and replace, mask underwater.

  7. Swim 100 feet without mask (no noseclip).

  8. Sink all equipment, fit while submerged.

  9. Share respirator with another diver.

  10. Breathe alternatively from respirator worn and spare carried.

  11. Change demand valve to spare cylinder whilst submerged.

  12. Navigate 200 feet with mask blacked out and guided by companion.

  13. Swim 200 feet fast at about six feet depth.

  14. Swim 60 yards on surface using snorkel and wearing respirator and weights.

  15. Jump into fairly deep water when wearing kit.

  16. Navigate a distance of 200 feet by compass unassisted by line.

  17. Demonstrate a method of artificial respiration.

JM Boon

October 1961

 

Banging in the Trouble Series

Readers of Fred Davies article on the discovery of the Trouble Series, Swildons Hole, in our last journal will remember mention of a small rift at the end of the northerly passage, and that this rift was attacked, without success, by Mike Thompson during the survey trip. Soon after Mike's attempt Oliver Lloyd and Howard Kenny used some explosives at this spot but also failed to cause enough damage to the stalagmite bosses to allow a human body to pass.

Wishing to solve the mystery of the sound of running water that came from beyond the stalagmite obstruction the Trouble Series was visited on Saturday 8th April 1961 by a party comprising of Mike Thompson, Fred Davies and Ken Dawe, accompanied by Mike Holland and Bob Pyke of the Wessex.

The two Troubles were passed without too much difficulty and when we reached the scene of operations we found that Oliver Lloyds last explosion had left a very useful crack beside the stalagmite bosses; it made a perfect site for four ounces of well tamped gelignite. Ignoring the fumes we returned immediately to the barrier after the first detonation and placed a second charge in the cracks opened up by the first. At the end of the afternoon we were very proficient at the rapid laying and firing of charges under cave conditions; all told there were four charges, each of four ounces.

With the debris of the final explosion out of the way Fred found that he could just force his way through between the stalagmite bosses into a narrow rift passage.

Six feet along this rift Fred found himself looking down an almost circular pot, six feet up in the left hand wall a small vadose trench discharged a small trickle of water which fell noisily down the pot. The rift did not continue across the other side of the pot. Some fumes and dust from the banging were still hanging in the air and these made it difficult to see clearly. The pot looked tight but it seemed to open out about four or five feet down; stones thrown into it indicated a depth of about ten feet and the water went down it. Much against his inclinations, Fred thought he ought to try. It proved to be an extremely tight fit on his hips and it proved very difficult to extract himself; a very thin man may find it possible to make a safe descent but the whole party were most unimpressed by the discovery and do not feel that a major discovery is now likely at this spot.

The final sentence of the preceding paragraph is probably the easiest way of ensuring that something is discovered at this spot.

Stop Press

Nyphargus has again proved its value as a tool for cave exploration when its originator used it to pass upstream through Sump Three from Swildons Four to the St Johns Bell. Details are lacking but we have heard mention of a 25 foot sump at a depth of 8 feet. Details later, we hope.

KR Dawe & FJ Davies

May 1961

 

Carricknacoppan Caves, Fermanagh, Northern Ireland

These caves were discovered by Liz and Mike Thompson on the afternoon of 27 May 1961 and were then partly explored by Mikes Boon and Thompson. The exploration was resumed at 5pm (not a typing error) the next day with the help of Steve Wynne-Roberts and a low grade survey made.

The three caves explored are all formed by a stream draining Cuilcagh mountain. The stream valley is some 500 yards west of Pollasumera and as one traverses from the source of this tributary valley to its confluence with the main Pollasumera gorge the following features are to be seen.

An impenetrable sink at the junction of an imperious drift cover with an exposed rib of limestone. This limestone rib outcrops for some 200 yards down valley to a point at which the stream resurges. The stream rises from a five feet high cave which was named Carricknacoppan One.

From this rising the stream can be followed on the surface for 220 yards to a second sink (shown on the OS 6 inch map) which may prove possible to force. However there seems to be little point in such a venture since a further 100 yards down the valley a pair of coalescent shakeholes give access to the underground stream, this was named Carricknacoppan Two whilst yet a further 100 yards down valley the most northerly of an irregular group of shakeholes again gives access to the stream. This last entrance is Carricknacoppan Three.

Carricknacoppan One, the resurgence cave roughly 600 yards from Pollasumera on a bearing of 230°, starts as a four foot high passage with clean benches of limestone flanking the stream. Forty feet upstream from the entrance daylight can be seen (this can be tied up with a sinkhole on the surface) and the stream enters from a low tunnel that was not explored.

The entrance to Carricknacoppan Two lies at the bottom of a twenty foot deep shakehole where a vertical opening leads directly into the active streamway. A triangular passage, six feet high at the apex, can be followed for 70 feet downstream to where the stream disappears into a small boulder choked passage.

Carricknacoppan Three is also found at the bottom of a shakehole. A muddy squeeze led to a six feet drop landing on a mud slide, a further 6 feet drop and more mud slopes led into the stream passage. At its downstream end is a choked pot which we attempted to clear. In high water the stream probably falls into this though at the time of exploration the stream sank into a silt choke a little higher up the passage. Upstream an attractive meander passage can be followed for 170 feet to a boulder choke. From the survey made it would appear that this is not far from distant from the downstream end of Carricknacoppan Two.

The total length of cave passage explored was about 300 feet. Exploration is not complete, One could almost certainly be followed upstream and there is a completely unexplored side passage in Three. Chances of continuing the exploration downstream in Three do not appear to be good.

MM Thompson & JM Boon

August 1961

Figure 2 – Sketch Survey of Carricknacoppan Caves

Figure 2 – Sketch Survey of Carricknacoppan Caves

Attachment

 Journal Series 03 Number 2