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
Wookey Hole Caves of the witch that prompted TV's "Most Haunted" team to visit Wookey Hole Caves and Mill to explore the location in depth, searching for evidence of paranormal activity. The show, which aired on 10 March 2009, was the last episode transmitted in series 11 of the show's run on the satellite and cable TV channel Living. In 2009 a new actor to play the 'witch' was chosen by Wookey Hole Ltd amid much media interest. Carole Bohanan in the role of Carla Calamity was selected ahead of over 3,000 other applicants. The cave was first opened to the public by