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Marble Arch Karst; John Thomas' HoleFermanagh
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Summary Full report
Site Type: Pothole
Site Status: PASSI
District: Fermanagh District Council
Grid Reference: H11883409
Rock Age: Quaternary (Holocene)
Rock Type: Limestone
Other interest: No data, No Data, cave, pothole

Summary of site:

John Thomas’s Hole, also known as Hallelujah Hole, Spider Hole and Pollpluda, is another system on the line of the Sruh Croppa River. Upstream it aligns with the northern end of the Pollasillagh/Mastodon cave from which it is separated by around 15m of sump passage and boulders.

The entrance is concealed by a boulder on the northern flank of a hollow and gives access to a complex and convoluted series of narrow rifts and crawls. It ends in a descent into the main chamber which is about 40m long by 20m wide at its widest point. A southerly extension ends in the boulder choke close to the end of Pollsillagh. A wide, muddy crawl to the north east, flanked by a stream on its southern side, leads to a pool. At the end of the muddy crawl there is a link to a parallel passage with narrow rifts at a variety of levels. A climb from one of the higher ones led to a choke which was cleared in 1975 to reveal a further 120m of zig-zagging passages, crawls, cave decorations and a mud canal, ending in a chamber. This is possibly linked to the terminal sump in Lower Cradle Hole (see site record ‘Marble Arch Karst; Upper Cradle Hole and Lower Cradle Hole’). The axis of John Thomas’s Hole trends in a north-easterly direction.

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