POT-HOLES ON THE ULSTER BORDER

By J. A. Holmes

Those Y.R.C. men who attended the 1947 Whitsuntide meet at Killesher – the first Irish meet since 1939 – could be divided roughly into two groups. The first had been there pre-war and had always enjoyed perfect summer weather even at Easter, each short visit leading to some new discovery on a grand scale. The second consisted of those men new to the Irish tradition of fine weather and exciting discoveries. Inevitably all those who could not stay the full week found this first visit somewhat flat. The weather was inclined to be cool and showery, the conditions on the moors wet and failure to accomplish much new left the impression that a week-end in Ireland was not worth the time spent in travelling.

The fortunate few who stayed out the week were favoured latterly with brilliant sunshine, and although doing compar­ atively little in the underground regions spent long hours on the moors. The lure of ” new ” country, as viewed from the summit cairn on Cuilcagh, spreading away into the hazy, distance, – and the cross-country trip to Shannon Pot – the source of the Shannon, put quite a different aspect on our Irish outlook.

The large quantities of food left behind by the week-enders must also have contributed in no mean way to the general feeling of contentment. The climax to the weeks’ activities came when the two younger members of the party were hurried out of the Legnabrocky Pots by a very senior member and compelled to escort a young lady through the Marble Arch Caverns!

At August Bank Holiday that same year a lone Rambler again enjoyed Mr. Barbour’s hospitality at Killesher, prepared to walk wherever inclination led. Inclination was largely governed at the outset by the Editor’s 6-inch O.S. maps with potholes and risings underlined in red ink and also by extracts from Hay ward’s ” In Praise of Ulster,” dealing with the underground caverns of the Swanlinbar River.

It was just as well he had little intention of doing any pot-holing or cave-crawling because on the evening of arrival the weather broke with a severe thunderstorm and three nights’ heavy rain turned dry stream beds into raging torrents. However, for the remainder of the week the weather was perfect with sunshine from morn till night and he was able to cover a fair amount of interesting country.

Broadly speaking the pot-holes in this area fall into four groups, comprising:

1. (a)  The Marble Arch group of river caverns.
2. (b)  The pot-holes in the Swanlinbar area.
3. (c)  The pots and caves in the Boho-Knockmore region.
4. (d)  The limestone country to the west of Black Lion.

Of these, the first has been the happy hunting ground of recent Y.R.C. meets. The latter area was dismissed by Brodrick as an area of no particular interest, and since then has received little attention.

The Boho area contains interesting caves, most of which have been described elsewhere, and a few deep pots such as Noon’s Hole, Reyfad Pot and Rattle Hole, all looked at the previous Whitsuntide. It seems possible that a more intensive explor­ ation of this area may be well worth the trouble.

Finally the Swanlinbar area ! The 6-inch O.S. map names several pot-holes on the limestone platform to the N.W. of Swanlinbar, completely overlooked till lately as they are on a tiny strip not worth buying ! Roberts and Chubb at Whitsun­ tide ’47 paid a flying visit to these pots揺idden among peat hags and cuttings – and saw enough to realise that there was pot-holing in this area sufficient to keep a strong party busy for longer than a mere week-end. The Pigeon Pots a mile and more to the North had been investigated in 1939, but the area became of especial interest after reading Hay ward’s ” In Praise of Ulster.” He describes how the upper reaches of the Swanlinbar River (also named the Claddagh) … ” rising in a fine gorge between Cuilcagh and Cratty pursue an underground course for over three miles through a maze of limestone caverns beset with a forest of fantastic stalactites.”

A wet morning with thick mist over the moors found the lone Rambler tramping stolidly up the banks of the Swanlinbar river. An even wetter afternoon and he was splashing his way methodically from South to North along and across, but mainly through, the several swollen tributaries of the same river and heading towards the high ground of Cratty and the featureless moors beyond. Much later that evening, the mist cleared, the rain stopped and he came upon a deep limestone gorge with a river hurling itself below ground under a fine limestone arch. The only limestone gorge on the Cuilcagh plateau east of Monastir Sink, and nothing to do with the Swanlinbar river ; this was Pollasumera whose waters rise again as a Cladagh at Marble Arch !

Other outings that week included a visit to Slieve Rushen, an isolated range of hills a mile or two to the east of Swanlinbar village. From the highest point a very clear view was obtained across the fertile lowlands of the Co. Cavan with Cavan Cathedral faintly discernible as a white blur in the far distance. The O.S. map names a Pollnagollum and Tory Cave. These were visited. The former was a deep pot hole with a floor then estimated at 70 ft., and the latter a muddy bedding-plane of no particular merit. Elsewhere in this region all streams flowed above ground and there were no signs of any other pot holes or even sinks.

On another wet day a circular trip from Swanlinbar via the Bellavally Gap to Glangevlin – lying south of the Cuilcagh-Tiltinbane ridge – droved no limestone country in this area, but the continuation of this walk N. past Shannon Pot and on to Black Lion was much more interesting and in limestone country all the way, very pleasant indeed. A deep sink named on the map Pollnagosson appears to be of interest. It is the deepest of a long line and engulfs a small stream flowing into a narrow cleft. It looks as though it would go without undue difficulty. Further investigations were, however, curtailed by the lateness of the hour and long dead mutton.

In general this lone visit served to confirm that a strong party could be well and truly occupied for a week in the Swanlinbar region alone and tackling only new pots. It may also be added that any person not even vaguely interested in pot-holing could not wish to find a more interesting corner of Old Ireland, the traditional Ireland of folk-lore, old-world courtesy, poverty and pride.

As a result of excellent staff-work on the part of the Club Secretaries, Whitsuntide 1948 saw yet another Y.R.C. party, 13 strong, cross the Irish Sea. After the usual smooth crossing we were packed at Belfast into a huge 3-ton lorry with all our gear, and away we went in brilliant sunshine to Enniskillen. Sam the driver has been mentioned elsewhere. He made the party up to fourteen and a very welcome addition he was. May the next Irish party be lucky enough to obtain his services.

We soon were settled in at Killesher and down to the job of planning our compaign. Reyfad won the day as our first objective on the grounds that it should be tackled while the fine weather lasted. Perhaps the 1947 party had deeper reasons.

Reyfad lies on the limestone platform about a mile to the south of Noon’s Hole – situated in the Boho area. There seems to be to-day no active stream engulfed but only seepage from the surrounding peat cuttings, sufficient to render descent under wet conditions unpleasant but not to explain the size of the main shaft.

Reference to the accompanying plan shows two small pot­ holes (A) and (J) in the same depression and perhaps 50 ft. apart, both leading into the closed main shaft, which at the level of (C) takes the form of a rift 40 ft. long by 15 ft. at the widest part. Incidentally its dome must be only a few feet below the moor.

Both pots were quite dry and were quickly laddered, the main attack being made via (A). The floor BC consisting of loose debris offered little in the way of a suitable belay for a long ladder descent and a stake jammed across the rift served that purpose. (CD) was a steep cleft in the main shaft leading to a narrow platform (D) about 2 ft. wide by 3 ft. long and forming the lip of the main ladder descent. 120 ft. of ladder were passed over this lip, the end soon out of sight below the overhang. A heavy limestone block lodged at the top of the cleft worked loose and threatened to send a minor avalanche of rocks down the whole ladder pitch. A rapid withdrawal to a safer level and hurried consultation resulted in abandoning descent via this entrance.

Meantime a second party had laddered the smaller hole which opened into the main shaft about 20 feet higher up and about the same distance to the north-east. Seventy feet of ladder dangled into the main shaft. A descent of 40 ft. showed the end of the ladder swinging well above a ledge of limestone on the brink of a still deeper hole. Back to the surface for all available tackle and down into the depth went seven ladders this time safely belayed to a stake set well back on the moor. The first man down quickly followed. – down, down without a pause, 100 feet, 150 feet, 200 feet. – at last a whistled signal to halt after paying out 210 feet of life-line, followed by a muffled shout of success.

A short rest and up again he came. Two further descents were made on two life-lines to investigate a rat-hole 18 inch by 12 inch in the floor of jammed boulders, and descending 6 feet to a substantial rock bridge. Partial clearance of the smaller boulders disclosed a rift down which stones could be dropped perhaps a further 50 feet. However, the instability of these smaller boulders forbade further investigations and the party withdrew to the surface. So ended a memorable day.

A description of the section is as follows :

1. A. – Ash tree at head of rift 5 ft. by 8 ft. About 30 ft. deep.
2. BC. – Loose debris floor sloping to narrow window (C) andopening into large closed pot.
3. CD. – Steep cleft holding jammed rocks, to platform (D).
4. J.K. – Smaller shaft than AB and 15-20 yards further north. 15-20 feet deep with sloping debris floor and opening into main shaft about 20 feet north and 15-20 feet above (C).
5. E. – Narrow ledge sloping outwards -2 or 3 feet wide and about 120 feet below K. Rock here clean and sound.
6. G. – Foot of the ladder. Floor of massive jammed boulders 30feet long by 12 feet wide. Dry and showing no signs of flooding.
7. H. – Rat-hole descending 6 feet. Possibility of a further 50foot pitch. The measured depth of this pot-hole from foot of ladder to moor level was 230 feet. In the main shaft the ladder hangs clear of the walls with the exception of the top 15 feet. The top 20 feet of the pitch below (K) was in the form of ridged lumps of black limestone, the surface breaking away in brittle flakes, though the under­ lying rocks appeared quite sound. Below this level the limestone was clean and white as far as F. At this depth the rock darkened and at the bottom it was black, brittleand abraded in sharp edges.

Our next objectives were the group of pots above Swanlinbar. Sam managed to convey us as far as the quarry and we then had a carry over the moor for about a mile to Polliniska Pot, digressing slightly from the direct route to look at Pollnagapple, a fine natural limestone arch on the edge of the moor.

Polliniska when visited the previous August engulfed a vast flood of water. This had now diminished to a moderate stream falling 30 feet into an open rift about 18 feet by eight wide. 30 feet to the north lay Pollnatagha, a deep well-like shaft about seven feet in diameter.

Polliniska was quickly laddered and explored. As was expected it proved to be a subsidiary pot to Pollnatagha, the water following a northerly channel and entering the latter shaft about 50 feet below the surface. A dry channel opening in the southern wall of the pot (W) merely led back to the main shaft.

After two or three unsuccessful attempts to bottom Poll­ natagha, all available ladders were put down and belayed to a convenient boulder on the moor. Down went the first man. At length his faint signal indicated he had bottomed at 168 feet. A brief interval for exploration and out he came to describe an extremely fine ladder descent with the ladder hanging clear of the walls the whole way and also clear of all but spray from the stream.

His brief inspection had revealed a vast circular chamber floored with boulders and peat washings, but with no obvious stream channel leading away.

Three further descents were made. One man roughly exploring the perimeter of the chamber with the sinks at (A), (D) and (C), while the other two extended exploration of (A).

The section and plan of this chamber are mainly impres­ sionistic.

X.W. Shaft of Polliniska wirh the stream entering over the southern lip.

Y.E. Pollnatagha shaft. The main chamber was roughly kidney shaped, perhaps 150 feet long by 100 feet wide and rising at (M) to a very high dome from which fell a smaller stream of water.

A. Sink about 15 feet long by 12 feet wide, descending 20 feet through mud and boulders to a steep narrow pitch 30 feet deep. This was laddered to a floor of stones.

Running water was heard but not encountered. From the foot of this pitch a dry passage J-K was followed without difficulty for 200 paces in a southerly direction against a strong current of air. Further exploration had to be discontinued for lack of time.

C. A sink similar to ‘A’ and requiring laddering was not descended.

A quaint feature of Pollnatagha noted by the men at the surface were the periodic puffs of cold air rising from the shaft and forming a localised evanescent mist. Surely a sign of a secondary air passage in the depths of the pot.

200 yards south of Polliniska and named on the 6-inch O.S. map is Pollprughlisk, a very fine looking pot and partly over­ grown with vegetation. It lies in a hollow about 15 feet deep and at the north end a small stream enters in wet weather. The south wall falls sheer from moor level to a floor of boulders 100 feet below. The rift lies roughly north-south and is about 20 feet long by 18 feet at the widest point. An interesting little scramble under the clints 50 feet across the moor leads one along an underground gallery smelling of foxes to a window opening into the north wall of Pollprughlisk and about 30 feet down. {Anglo-Irish gh is the Scotch ch.)

All ladders were sent down the main shaft and descent made from the northern end, down a good pitch of 100 feet, the ladder hanging clear for the lower two-thirds. The pot at this level consists of a rift approximately 60-70 feet long by 10 feet wide, running roughly 50 deg. true and descending over boulders and debris a further 20 feet to the lowest part of the rift (E). Here in the West wall is an opening (D) originally 8 feet above floor level, but subsequently lowered considerably by kicking away masses of loose limestone blocks, etc. This opening led to a closed parallel rift (H-J), at this level only three feet wide and spanned opposite (D) by three large boulders precariously balanced. These were crossed to a platform (C) about 12 feet square and sloping steeply towards the closed rift. This appeared about 50 feet deep, but prior to rigging the ladders much hard labour was expended in levering away several loose rocks, jammed at the head of the rift.

The ladders down this pitch were belayed through (D) to a large rock in the main rift and the ladders themselves ran over a stout stake (K) jammed across the rift. These precautions were necessary on account of the extremely brittle nature of the black limestone. This second rift was found to be floored with a thick mass of peat descending steeply from south to north to a tightish arch (M) leading to a deeper continuation of the same rift (N-J). This proved to be the end of the pot. The floor consisted of peat washings and mud. The walls were covered with slime and the whole rift petered out as a small drain. The depth below moor level was estimated at 205 feet. Eight men made the complete descent.

In times of flood this rift must be immersed to a depth of 90 feet since pieces of wood and drift were lodged at a height of 10 feet above the platform (C). Like Slieve Rushen Pollnagollum and unlike Polliniska it consists of a series of open joints in the limestone enlarged by acid corrosion from the peat. In this type of system and where the water can only drain away slowly the greatest corrosion will take place in the lower regions where the water is under pressure. Enlargement by erosion will be practically nil since the rate of flow of the water is negligible. Consequently one will find high banks and walls of rock merely cemented together by peat and mud which in an actual stream cavern would have been washed away. On the other hand the upper walls of such a pot with the exception of the top few feet may be quite sound.

Peter Bryant’s Bullock Hole, the last big pot on this stretch of moor, lies within 200 yards to the north of Polliniska. Once more all the tackle was left overnight at Pollprughlisk.

On Wednesday morning three Ramblers, detached from the main body, were despatched at a very early hour complete with single rope and ladder to walk from the Border through Swanlinbar to explore the Aghaboy Pollnagollum, whose passages, according to Hayward, extend over half a mile under the moor. The remainder of the party were to tackle the Bullock Hole, but at a more reasonable hour.

Situated on the edge of the moor, in the townland of Aghaboy and about 1½ miles to the south of Polliniska, this Pollnagollum is a fine open pot roughly 30 feet wide by 50 feet long in a north-south line and thickly overgrown with vegetation. A small stream falls in wet weather over the north wall.

Guided by an old countryman the party descended the fifteen feet to the rocky floor by an easy scramble down the south wall and without need of any tackle. A steep boulder-strewn slope led to the foot of the north wall – a limestone crag 40 feet high. Of three passages leading under this crag, only the centre one proved of any interest and this petered out after 70-80 yards. Neither of the other two extended more than 50 feet.

Polladranta marked on the six-inch map must be a small lochan, search being made for it while returning over the moors to the Bullock Hole.

This last pot-hole lies in the hollow about 20 feet below moor level with two or three small trees growing nearby. A small stream enters from the west. The rift itself is about 8 feet wide by 10 feet long. A pitch of 25 feet at the north end leads to a commodious floor of boulders. The stream strikes the lip of this shelf and cascades down a steep pitch of 70 feet to a substantial ledge. From here to the floor of the large chamber is a further 60 feet. On the other hand the south wall of the rift forms a slight overhang from moor level to the ledge, clear of all projecting rocks and also out of the stream.

Eight men made the descent into the large chamber which is roughly rectangular in shape. A continuation of the slope below the foot of the ladder added a further 20 feet to the depth of the pot giving a total of 180 feet below moor level. The dimensions of this vast chamber were measured at 120 feet by go feet. No further pitches or passages were found and if any exist they may well be hidden under the pile of limestone blocks rising 20 feet or more in the centre of the chamber.

A quarter of a mile to the north-east of the Bullock Hole the main track off the moor literally skirts a hole only 2 feet by 4 feet, unfenced or protected in any way and level with the surrounding moor. Known as Peter Bryants’ Hole, it had the reputation of being the deepest hole on the moor. A quick inspection, however, showed that a single ladder and a long hand-line would be sufficient to bottom the rift.

Thursday was a rest day-which meant the only trip organised was one undertaken by Mr. Barbour and six Ramblers to partake of the fleshpots of Sligo.

The two men on fatigues, after completing their chores, made history by boating into Cradle Hole and back from the Grand Gallery of the Marble Arch Caves. What a great pity that lack of time precluded taking advantage of the exceptional dry spell to see what further additions could be made to this already extensive underground system.

Three other men eschewing the attractions of Sligo returned to finish off Peter Bryants’ Hole. This proved a pleasing rift, clean, easy of access and well endowed with stalagmitic formations. Maximum depth was estimated at 130 feet below moor level and a length of 170 feet.

A single ladder belayed to a stake led down a vertical pitch of 15 feet and thence down a steep stalagmitic slope to a level platform (CD), on which lay a large creel lost by one of the peat-cutters two years previously. The rift, bearing approxi­mately 30° true, now widened to about 10 feet and descended via a loose scree slope for 80 feet to a point (G). Here it was about 25 feet high and blocked by stalagmite deposits save for a low arch. Beyond, the scree slope continued at an easy angle for another 30 feet but bearing now 45° true.

A steep climb of 20 feet down easy rocks led to the lowest level attained. The floor after a further 30 feet rose steeply over cemented limestone blocks to within six feet of the roof (L). A funnel (M) 2 to 3 feet wide, 12 inches high and containing masses of short straw stalactites continued in the general direction of the rift for some distance. It was not attempted.

A peculiar feature were the thin ” shelves ” of deposit on opposite walls of this rift, as though in times past they might possibly have been joined to form a false floor, which through later subsidence of underlying blocks had given way to the present floor level. A disturbing thought that the present flooring may also be of the same nature.

The handline of 220 feet was belayed to a stout white stalagmite at the foot of the ladder, and though not essential was a great help.

The day finished with a climb to the summit cairn of Cuilcagh and thence via Pollasumra and Monastir Sink to Killesher.

One full day now remained to us and we had only one more large pot-hole to add to our list. Friday saw us gathered with all our gear around the Slieve Rushen Pollnagollum. Just how we got there safely Sam alone knows. For this one of our “first descents” Sam could surely claim a “first ascent.”  His lorry seemed to shrink into the narrow lanes.

Pollnagollum consists of a triangular shaped rift about 10 feet long by 6 feet greatest width, and lies about 8 feet below moor level. It is surrounded by the usual vegetation and low wall of turves.

Four ladders belayed back on the moor to a stake were dropped mid-way along the northern wall. A good first pitch of ioo feet was broken by a steep platform 70 feet down. The rock on all sides appeared brittle and rotten as in the second pitch of Pollprughlisk. Thin layers of protruding black limestone banded with layers of lighter hue, gave an impression of artificiality.

From the foot of the ladders (C) a high closed rift about 6 feet wide and bearing 50°descended for 30 feet at a gentle angle to a short ladder pitch of 20 feet (D) down what appeared to be the face of a peat bank. A further short slope of peat and debris led to a second vertical pitch (F) 12 feet high, consisting of loose rocks cemented by peat and proving very treacherous, since several rocks were dislodged here and bounded to the bottom of the rift below.

Further progress now lay along a second narrow rift bearing at 85°to the original one. Here the rock seemed sounder as evidenced by the wide ledges on both sides. A descent of 20 feet down these ledges brought one to a rock floor (H). At the northern end a drop of five feet through a narrow opening led into a short but somewhat wider chamber (J). Here the rift closed and quaintly enough, attached to a bank of peat washings was found a large white cocoon.

Four feet above the floor (H) a deep ledge surrounds the South end of the rift and leading away are three muddy crawls

in directions West, South and East. The first two soon became too tight. The latter was followed through thick mud for 25 to 30 feet to the head of a rift (K) approximately 10 feet long by i-J to 2 feet in width and bearing 50ｰ most likely an extension of the original rift (CF). This was laddered with difficulty to a depth of 32 feet (L) by one man who reported no further possibilities in the thick mud. The depth here was estimated at 215 feet.

It seemed quaint that only this one pot-hole should exist on the whole of Slieve Rushen. Extensive search the previous August failed to reveal the shallowest of sinks.

So back to Killesher and a swim before supper in the icy waters of the Cladagh. The last night of a very happy week was spent across the Border in the town of Black Lion with Mr. McGovern of ” The Bush ” as mine host.

Sunday we spent packing up and making ready for the return journey. Nevertheless we found time to take one last look at the Glen and the Marble Arch Caves, lingering awhile on the top of Skreen Hill. The weather which had been perfect all week showed signs of breaking. When eventually we reached Belfast, it was in cold pouring rain.

Other caves and risings which were visited and found to be of no special interest were Brocky Cave on Benaughlin, Greenan Rock Cave, Pollinjska (Rising) and Sumera (Rising), all in the Swanlinbar area.

Pollboy, Pollahune and Pollnaowen sinks engulfing quite large streams on the lower ground North-east of Tiltinbane, offer no possibilities.

For future pot-holing expeditions, exploratory work still remains to be done in Polliniska and also Reyfad. The pos­ sibilities of the underground river caverns in the Marble Arch area, given dry weather, are perhaps not exhausted, and Rattle Hole near Reyfad has yet to be descended to its ultimate end. All this apart from survey work to be completed.

However, if a small but active reconnaissance party can be raised early next year to cover new ground, then the next Irish meet, given reasonable weather, will be an even greater attraction than the last.

Whitsuntide 1947. – Armstrong, Chubb, Roberts, F. S. Booth, Chadwick, Holmes, Godley, Marsden, F. W. Stembridge. (9-)

Whitsuntide 1948. – Armstrong, Chubb, Roberts, W. Booth, Godley, Marsden, Holmes, Cullingworth, Spenceley, Haslam, H. Stembridge, F. Stembridge, Burton. (13.)

GEOLOGICAL NOTE. – Fermanagh, like much of Ireland, is based on Carboniferous Limestone covered with Drift with mossy peaty areas. E. & N. of Ennisldllen Old Red Sandstone extends from within Tyrone to the shore of Lower Loch Erne. Near Florence Court to the south the bold upland mass of Cuilcagh (2,188 ft.) rises from the Lower Limestone to a wide platform of Upper Limestone above Middle Limestone (Calp) followed by a long steep ridge of Yoredales capped with Millstone Grit. On the side we know so well it closely resembles Ingleborough, but the limestone platform is far wider and more covered with drift; at its eastern (Swanlinbar) side is a huge area of peat-diggings.

The swallets of the Marble Arch group of caverns on the northern edge are at about 600 ft. above sea, and the newly-discovered Polliniska group of pot-holes among the peat-diggings is at 1,000 ft. on the eastern edge. The risings, Hanging Rock Cave, Cascades in Marble Arch Glen, the so-called Polliniska near Mullan Quarry, Sumera, etc. are thrown out by the calp which seems to contain few beds other than shale and sandstone.

Hull’s section in Stanford’s Geological Atlas shows the Upper Limestone dipping to the south from the Marble Arch. As there is a steady S.E. ascent on the limestone thence to Pigeon Pots and Polliniska there are evidently questions for study. I understand that apart from the general survey, not much detailed work has been done in the N.W.  – Editor.