Mendip Hills to the development of cave diving in Britain. The first cave dive was attempted at Swildon's Hole in 1934, and the first successful dive was achieved the following year at Wookey Hole Caves, which has the deepest sump in Britain at 76 m (250 ft). The cave complexes at St. Dunstan's Well Catchment, Lamb Leer, and Priddy Caves have been identified as Sites of Special Scientific Interest. The deepest cave in the Mendip Hills is Charterhouse Cave with a vertical range of . Many caves in the Mendip area were excavated for archaeological and natural history studies by pioneer explorer
Caves of the Tullybrack and Belmore hills which it is formed comprises Dartry Limestone and Knockmore Limestone. The site, which is designated a PASSI, features a narrow bedding plane leading for 12 m to a waterfall and a duck. It has been speculated that the water from this sink also joins the Noon's Hole drainage system. Caves of the Tullybrack and Belmore hills The Caves of the Tullybrack and Belmore hills can be found in south-west County Fermanagh, Northern Ireland. 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.