Caves of the Tullybrack and Belmore hills

The region is also described as the West Fermanagh Scarplands by environmental agencies and shares many similar karst features with the nearby Marble Arch Caves Global Geopark.

[3] The caves and related features are formed predominantly in the Dartry Limestone Formation – a sequence of rocks assigned to the Asbian sub-stage of the Visean stage of the Carboniferous period.

Cave development occurred within the Quaternary period and certain features are ascribed to the Holocene epoch of the last 10,000 years.

With the exception of Arch Cave, all of the caves and related karstic features listed below have been designated as provisional Areas of Special Scientific Interest (provisional ASSIs, or PASSIs), a conservation designation in Northern Ireland equivalent to SSSIs in other parts of the United Kingdom.

There are two passages in this cave estimated to be about 8 m (26 ft) long, one of which has been enlarged as a souterrain and is also a scheduled ancient monument.

The cave can be entered by a previously collapsed roof structure through which a large waterfall flows.

[9] Early speleological visits to the cave include that of Henry Lyster Jameson in 1895, primarily to collect specimens of fauna.

The Northern Ireland Environmental Agency describe this system as follows: "the quality of geomorphological and geological features in the Reyfad–Pollnacrom–Polltullybrack cave system make it arguably the most important underground karst site in Northern Ireland.

The main body of water flowing through the cave is traversable, but there is a 10 m flooded sump which emerges in another section known as the Farr Out Series.

Fairy Cave has been speculated to be part of a previous series of passages of the main Reyfad system.

There is a small passage that runs along the joints of the bedrock and is only 1 m in height, which terminates in a sump; beyond this is a silt-choked hole.

There are a series of chert base levels which have been broken up to give access to further passages.

When the substrata changes into Knockmore Limestone, the character of the cave changes to a more vertically oriented passage.

The rocks of this formation date from the Quaternary (Holocene) period and consist of limestone.

Murphy's Hole is situated at the north end of a depression that also contains Seltanacool Sinks.

A waterfall drains into the sink, which takes a large volume of water in heavy rains.

The substrata from this formation dates from the Quaternary (Holocene) era and is composed of limestone.

The rocks from this formation are composed of Dartry and Knockmore Limestones with chert and gypsum.

The cave contains two shafts at 50 and 15 m respectively, which permit entry to the main stream passage which trends in a north-west direction for 100 m (330 ft) before turning south.

The rocks in this second major entrance to the Reyfad system are composed of Dartry and Knockmore Limestones with chert and calcite formations.

Just before this are chambers known as the 'Grottoes', which contain fine examples of calcite features including stalactites, helictites and cave curtains.

Rattle Hole consists of a single shaft of 36 m (118 ft) depth, which terminates in a boulder strewn base.

Further efforts at extending this passage have proved fruitless, but as a result of dye testing it is known that the water from here emerges at Carrickbeg.

[4] This site is a PASSI and is a very active cave with many calcite formations and fossiliferous limestone, which includes evidence of Brachiopods and Crinoids.

It is thought that the sinks, which are situated in the same depression as Murphy's Hole,[17] link to Carrickbeg Rising.

This sinkhole contains a substantial shaft of 30 m (98 ft) depth, with some crawling sections and short passages which ultimately end at an impenetrable crack in the rocks.

Situated 50 m from Knockmore summit, this is a small cave of mainly archaeological significance, and is partially man-made.

[38] The cave is named for the art and writing of varying age inscribed on the walls.

The cave, described in the paper by Wakeman in 1868 as lying 'in the midst of a desolate, heath-clad highland, which extends over a considerable portion of northern Fermanagh, with no trace of cultivation, ancient or modern" .

The site, which is designated a PASSI, features a narrow bedding plane leading for 12 m to a waterfall and a duck.