Wookey Hole Caves then passes through major cave systems such as Swildon's Hole, Eastwater Cavern and St Cuthbert's Swallet, around Priddy, but 95% is water that has percolated directly into the limestone. The southern slopes of the Mendip Hills largely follow the flanks of an anticline, a fold in the rock that is convex upwards and has its oldest beds at its core. On the Mendips the crest of the anticline is truncated by erosion, forming a plateau. The rock strata here dip 10–15 degrees to the southwest. The outer slopes are mainly of Carboniferous Limestone, with Devonian age Old Red Sandstone exposed
Hellfire Caves Hellfire Caves The Hellfire Caves (also known as the West Wycombe Caves) are a network of man-made chalk and flint caverns which extend a quarter of a mile (250 metres) underground. They are situated above the village of West Wycombe, at the southern edge of the Chiltern Hills near High Wycombe in Buckinghamshire, Southeast England. They were excavated between 1748 and 1752 for Francis Dashwood, 11th Baron le Despencer (2nd Baronet), founder of the Dilettanti Society and co-founder of the Hellfire Club, whose meetings were held in the caves. The caves have been operating as a tourist attraction since 1951.