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 gate servicing the paper mill was built about 1852. The tunnel excavated from the third chamber to the ninth chamber and then out to daylight was dug in 1974–1975 by ex-coal miners from the Radstock area. The show cave was further extended in 2015 by excavating a tunnel from the ninth chamber to the 20th chamber. The constant temperature of in the caves is used by Ford Farm of Dorset to mature Cheddar cheese in the 'Cheese Tunnel' – an excavated side tunnel between the ninth chamber and the exit to the show cave. Archaeological investigations were undertaken from 1859