| This area contains the magnificent Reyfad-Pollnacrom- Polltullybrack cave system which has a great variety of passage forms and very good speleothem deposits. It is a pre- to interglacial system with large fossil phreatic trunk passages containing the most extensive subterranean glacial sediment deposits in Northern Ireland. The system is the longest and deepest cave in Northern Ireland, the 9th deepest and 18th longest in the U.K. (Corbon et. al., 1989) and has the largest passages and the deepest underground shaft discovered to date in Ireland. It has the greatest potential for further passage discoveries in Northern Ireland.|
| The Reyfad - Carrickbeg area lies between the Noon's - Arch catchment and the Boho area. The 9km2 catchment consists of a series of N-S trending limestone benches and scarp slopes along the eastern side of the Tullybrack Uplands. Five major streams flow eastwards from the sandstone and shale capped Tullybrack plateau and sink into the Dartry Limestone to feed the streamways in the Reyfad-Pollnacrom-Polltullybrack cave system. The water resurges at Carrickbeg Rising at the Dartry - Glencar contact. Water sinking at Ivy Hole, Rattle Hole, Mad Pot, Murphy's Hole, Pollmore, Pollbeg and many minor sites is also assumed to resurge at Carrickbeg Rising.|
| Major speleological sites: Reyfad-Pollnacrom-Polltullybrack (Reyfad Pot H0889 4687, Pollnacrom H0853 4702, Polltullybrack H0921 4672) (~6700m long, 193m deep) and Carrickbeg H1172 4670 (~1000m long).|
| Minor speleological sites: Mad Pot (H0944 4666), Little Reyfad (H096 465), Rattle Hole (H1023 4633), Murphy's Hole (H1005 4613), Seltanacool sinks (H102 458), Ivy Hole (H1069 4635), Fairy Cave (H0925 4750), Oweyglass Caves (H100 470), Pollmore (H1165 4582), Pollbeg (H1174 4557).|
| Surface sites: Good and extensive limestone pavement, Sheet 210 in grid square H10 46 (approximately located in the 100m grid squares 0E 6N, 1E 6N, 0E 5N, 1E 5N, 2E 5N, 1E 4N, 2E 4N, 3E 4N, 1E 3N). Braad Dry Valley (H109 465).|
| Approximate catchment area: ~9km2. Total surveyed cave in the area: ~8000m. Approximate area of exposed karren: ~1000m2. Total area: ~9km2.|
| I - Hydrology|
| There are five major streams which flow northeast from the Tullybrack Uplands and sink into the Dartry Limestone. They feed into a complex subterranean dendritic drainage system via vertical conduits. Some dye traces have been completed (Jones, 1974; Clark, H.U.S.S., 1975; Kelly, 1990) which indicate that Carrickbeg Rising is probably the present day resurgence for the whole area.|
| The routes taken by the five streams from the surface and through known cave passage can be summarised as follows.|
| The stream entering Polltullybrack (at 310m amsl) flows via the Main Aven to the Main Stream Passage and is known as the Reyfad Stream. It has two major tributaries, one assumed to come from Bush Sink via Rory's Aven and the second via Reyfad Pot. The Reyfad Stream continues south via the Southern Inlet and Aghnahoo Extension Passage and has been followed as far as Sump 3 at ~130m amsl. This stream has been positively traced to Carrickbeg.|
| Water entering Watson's sink (at 280m amsl) feeds via Watson's Way and the Northwest Inlet into the Reyfad Main Stream in the camp site area. Waterfall Sink (at 270m amsl) almost certainly feeds the New River and is soon lost in a boulder choke, but has also been positively traced to Carrickbeg. The water entering the system (at 280m amsl) via the Pollnacrom entrance shaft pursues an independent course to its sump. The Heaven and Hell and Reyfadhoo streams appear to unite and enter an impenetrable sump at the south limit of the Reyfadhoo Passage.|
| In Carrickbeg Rising Cave the main flow emerges from a sump 700m from the entrance and is joined by a significant inlet 150m before the resurgence (at 80m amsl).|
| It is postulated that the water sinking at Ivy Hole accounts for the major inlet in Carrickbeg Rising Cave and that the Pollmore and Pollbeg waters also feed to this resurgence.|
| The small streams entering the numerous sink holes e.g. Mad Pot, Murphy's Hole, Rattle Hole etc. on the peat covered bench to the southeast of the cave system are assumed to be part of the same dendritic drainage system.|
| II - Underground Karst|
| (i) Reyfad-Pollnacrom-Polltullybrack|
| For detailed site descriptions see;
Key Site 391 - Reyfad Pot Key Site 392 - Pollnacrom Key Site 393 - Polltullyard.
(ii) Carrickbeg Rising Cave
For detailed site description see;
Key Site 394 - Carrickbeg.
(iii) Minor speleological sites
For detailed site descriptions see;
Key Site 395 - Mad Pot Key Site 396 - Little Reyfad Key Site 397 - Rattle Hole Key Site 398 - Murphy's Hole Key Site 399 - Seltanacool Sinks Key Site 400 - Ivy Hole Key Site 401 - Fairy Cave Key Site 402 - Oweyglass Caves Key Site 403 - Pollmore Key Site 404 - Pollbeg.
III - Surface Karst
The Reyfad uplands attain a maximum height of 386m and are flanked by a series of low northeast facing sandstone cliffs. One obvious valley, at Carricknaboll, breaks the scarp and brings water off the upland into the depression at Edenybreslen. Active peat bog covers the sandstone and shale uplands and part of the limestone bench trending southeast from Edenybreslen for ~3km. There are numerous sink holes in the peat bog, some of which are known to feed the Reyfad drainage system. Around the 310m contour peat bog gives way to limestone grassland with areas of limestone pavement and small cliffs. At the southeastern end of the bench, below Brennan's Rock, is a large closed depression with Murphy's Hole at its northwest end.
A steep scarp slope drops away from the bench into an area of complex topography between the 300m and 200m contours. There are a number of dry valleys with prominent cliff lines in this area e.g. Carricknabiller, Oweyglass, Legloughra and Braad. Braad and Oweyglass have small rising and resinking streams in the valleys. Between the 200m and 150m contour another bench is discernible before the final scarp slope at the edge of the Screenagh-Sillees valley. At the base of this scarp is the Dartry-Glenade Limestone contact and the spring line on which Carrickbeg rising is located. Above the rising and the road a vegetated limestone scree slope leads up to the base of the Carrickbeg cliffs.
For site specific information see;
Key Site 438 - Braad Dry Valley.
| The Reyfad-Pollnacrom-Polltullybrack cave system can be regarded as the most important underground karst site in Northern Ireland. In a regional context, it contains the most extensive system of passages, it has the greatest volume of passage and attains the greatest depth of passage from sink to the lowest explored point in the system.|
| Many other facts and statistics about the cave add to the importance of the Reyfad System both regionally, nationally and internationally. The total length of surveyed passage is 6700m and the depth from the highest entrance to the lowest point in the cave is -193m. The average size of the main trunk passage is approximately 12m wide by 10m high, and the distance from the end of the known passage to the resurgence at Carrickbeg is 3000m. There is a height difference of 232m from Polltullybrack to Carrickbeg and from the end of the Aghnahoo Extension passage to Carrickbeg the height difference is 50m.|
| The clastic sediment deposits are the most extensive underground glacial/post-glacial deposits in Ireland. They will contain abundant information on the paleoenvironments of the area. The speleothem deposits are extensive and varied and a wide range of passage cross-sections and smaller features of erosional morphology are present. There is great potential for further research and exploration in the area and the investigation of the hydrology of the catchment is of great significance to Northern Irish speleology. There is an estimated minimum of 5km of passage to be discovered between the Reyfad System and Carrickbeg Rising.|
| Surface karst features are also well developed within the area including limestone pavements, dry valleys, solution and collapse dolines, relict caves and potholes.|
| I - Hydrology|
| To the north of the Reyfad area the karst watershed boundary is probably along the Pollanaffrin fault but to the south, the hydrological boundary between the Reyfad - Carrickbeg catchment and the Boho catchment is unclear. The delineation is possibly influenced by another E-W fault, here termed the Boho Churches Fault. A dye trace at Pollmore, which would have given some indication of the subterranean watershed, was unsuccessful.|
| It is clear from the surface and underground topography of this area that the present day drainage is superimposed on major features which have been formed and modified by glacial and interglacial episodes.|
| A major part of the recent drainage in the cave flows through the Aghnahoo Extension Passage. This follows a 010° fracture almost exclusively for 1250m, taking the drainage under the sandstone and shale cap of the Tullybrack Uplands and away from Carrickbeg rising. In flood the passage is unable to drain the system fast enough and the whole area backs up as far as the Southern Inlet Passage. Foam at the Southern Inlet - Aghnahoo Extension connection, ~20m above normal stream level, shows that a major backing-up event occurred during the winter of 1994-1995.|
| The other three streams in the system, New River, Pollnacrom and Scrapers', together with the Reyfad stream are assumed to collect in a master cave before resurging at Carrickbeg, probably in conjunction with the streams sinking at Rattle Hole, Mad Pot, Murphy's Hole and possibly Pollmore and Pollbeg. Carrickbeg Rising Cave appears relatively young in comparison to the main passages of the Reyfad system, and is not believed to be the resurgence during the development of the large horizontal passages within the Reyfad System.|
| II - Underground karst|
| The Reyfad System is composed of a series of large, mostly abandoned, sediment filled passages with recent reinvasion of these older passages by modern streams.|
| In the Reyfad Main Stream Passage, the four main phases of development can be clearly seen. The first phreatic phase is indicated by the remnant half tube and the phreatic sponge work in the roof. The second phase, vadose down cutting, resulted from lowering of the hydrological base level and is associated with major passage enlargement and breakdown. The third phase resulted in the infill of the vadose passages with huge quantities of sediment and the fourth phase is the present day reworking of the sediments by reinvading streams.|
| While most of the sediment infill is still in place, the presence of calcite canopies isolated on the passage walls up to 6m above present floor level gives an indication of the total depth of sediment removed.|
| The passages which link the major reinvaded sections of the cave, for example Circumlocution Convolutions, are possibly part of the fourth phase of speleogenesis, while the shafts of the Main Aven, Rory's Aven, Reyfad Pot and Pollnacrom are more obviously part of this phase. Scallop markings in the Main Passage indicate that the general flow direction through the system has remained from north to south thoughout the development of the system.|
| Chemical sediments, predominantly calcite and gypsum, are found in a number of areas in the system where they are, in general, deposited on top of clastic sediments, indicating that the major recent deposition of chemical sediments post-dates the sediment infill. The Aghnahoo Extension has very few calcite deposits as it is developed under the impermeable sandstone-shale cap.
III - Surface karst
Brook (1971) suggested the most probable source of the large quantities of water required to develop the system came from the repeated diversion of all the drainage to the northwest of Reyfad by an ice sheet pushing south from Donegal. The ponded water would have been forced through the valley at Carricknabol to sink into the limestone in the depression at Edenybreslen. Fairy Cave, which exhibits poor inward flow markings, could represent an early stage of this process. Fluvio-glacial action towards the end of the last glacial period could have transported the huge deposits of sediment into the cave.
Any of the Carricknabiller, Oweyglass, Legloughra or Braad dry valleys could be associated with a fossil resurgence for the system.
| The area has been demonstrated to contain underground and surface karst features which are of regional, national and international significance. The statistics for the system are impressive and place it as one of the premier caves in Britain and Ireland. The quantity and quality of karst geomorphological and geological features of scientific interest within this karst unit are unsurpassed in Northern Ireland.|
| Pollbeg and Ivy Hole are of sufficient importance within the Reyfad - Carrickbeg karst unit to justify a refuse clean up programme which would reinstate the site's quality.|
| There are also a number of sites associated with the karst which support intermittent bat populations.|
| For information and reference lists on the systems and features of other karst areas within the Belmore, Ballintempo and Tullybrack Uplands see;|
|Key Site 1158 - Belmore Key Site 1159 - Boho Key Site 1161 - Noon's Hole-Arch Cave Key Site 1162 - Knockmore-Pollaraftra.|
|No fauna has been recorded from this site and no collection was made in the course of the current programme. A number of very limited observations were made and the impression is that the system has a paucity of cave life.|
|A number of individual fresh water shrimps (Gammarus duebeni celtictus) were found living in the Watson's Way stream and the Main Stream Passage has mud banks with worm casts.|
|The relict caves of Oweyglass have populations of the common cave spider (Meta menardi), herald moth (Scoliopteryx libatrix) and fox (Vulpes vulpes).|
|A single bat was observed roosting in one of these sites during November 1994.|
|Restrictions:||Landowner access restrictions to shafts.|
|Planning:||HISTORY OF EXPLORATION Exploration of this cave system started in 1939 when the Yorkshire Ramblers Club (YRC) descended the first pitch of the pothole, but it was not until 1960-62 that the same group descended the rest of the pothole and began exploration of the major horizontal passages. Exploration by the YRC extended upstream as far as the Main Aven, downstream to the Southern Inlet (strangely named as it was then an outlet) and from there 300m up the North West Inlet. In 1962 Pollnacrom was descended and explored downstream to the sump by Craven Pothole Club. At the end of the 1960's the North West Inlet had been extended into Watson's Way and up the Old Bog Road to the New River by Irish Cavers. During the 1970's Hull University Speleological Society connected Reyfad and Pollnacrom after the discovery of Scrapers' Hole by the Reyfad Group. The Reyfad Group then explored the major southern extension of the Main Stream Passage, the Aghnahoo Extension. Diving exploration, in conjunction with the Cave Diving Group, pushed this passage to the deepest and most southerly point, 193m below the highest entrance, Polltullybrack. In the 1980's and early 1990's the connection with Polltullybrack was completed and Rory's Aven was climbed extending it closer to Bush Sink. Many other sites have been investigated in the area but the rising at Carrickbeg and Mad Pot are the only two which have been explored for any distance. In Carrickbeg the Reyfad Group and Welsh divers from the Cave Diving Group explored ~1000m in 1976 and in Mad Pot, Hull University Speleological Society reached a depth of -40 metres.|
|Management:||Internal threats: Access to the Reyfad-Pollnacrom-Polltullybrack cave system is restricted to those with vertical caving skills via one of the three shaft entrances. This and landowner access restrictions has limited the number of groups to a minimum during the last few years. The entrance potholes are equipped with permanent artificial anchor points for ropes which will be replaced and upgraded in the future by members of the national governing bodies (SUI-ICRO). Over 50% of the horizontal cave in Reyfad can be regarded as low to medium energy and is therefore delicate. The passages are, however, large and routes along them have become well defined in the sediment banks. Visiting groups in general remain on these paths which limits damage. This also applies to the routes which lead over the sediments in the Southern Inlet where the surface cracking mosaic is particularly vulnerable to damage. The Aghnahoo Extension Passage is a high energy passage in which water backs up regularly. The most important areas of calcite speleothems are the Grottoes, Formation Passage, Watson's Way, the Old Bog Road and Dreamer's Diversion - Joe's Roe and in some of these areas, the route through is very close to delicate features. Similarly the gypsum deposits in the Gypsum Crawls and Gypsum Cavern are particularly threatened by the passage of cavers. External threats: During the past ten years a number of drainage ditches have been opened leading water into sinks in the Reyfad Entrance area which has increased the amount of water and the sediment load carried into the cave. The disposal of fallen animals into surface potholes has been a traditional problem in the Reyfad-Pollnacrom-Polltullybrack area and incidents remain high. These remains do disappear over a season which is not the case with household waste and dumping in some sites closer to habitation is prevalent (Pollmore and Ivy Hole). If waste input was stopped, a programme of rubbish removal from these sites would reinstate their quality. Water quality could be regarded as relatively good in the known underground drainage channels of the system. If, however, Pollmore water feeds into the system this would probably have a detrimental effect on the water quality.|
|Threats:||Accidental damage by cavers; increased sediment load into cave; dumping of fallen animals and household waste.|
|Potential:||The potential for fruitful research and exploration in the Reyfad-Pollnacrom-Polltullybrack system is massive. The complex hydrology of the area has received very limited attention leaving the following sinks untraced; Bush Sink, Watson's Sink, Mad Pot, Keyhole Sink, Murphy's Hole, Rattle Hole, Ivy Hole, Brennan's Rocks Sink, Seltanacool Sink, Pollmore and Pollbeg. There is an estimated minimum of 5km of passage between the limits of exploration in the system to the end of Carrickbeg Cave. The main areas where speleological exploration could take place are; Coleman's Cavern, Rory's Aven, Reyfadhoo, downstream Aghnahoo and all the surface sites listed above. The detailed study of the clastic sediments found in the Reyfad system may reveal more information on the glaciation of the area and the speleogenesis.|
|Educ. Level:||Not entered|