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
Cheddar Gorge monuments as nationally important archaeological sites including: Gough's Old Cave, Great Oone's Hole, Saye's Hole, Soldier's Hole and Sun Hole. Cliff Road (B3135), which runs through the Gorge, offers a popular climb for bicyclists and has a maximum gradient of 16%. The ascent featured in stage 6 of the 2011 Tour of Britain. There are about 350 officially graded rock climbing routes on the 27 cliffs that make up Cheddar Gorge, which are generally open to climbers between 1 October and 15 March each year. Each of the routes is named and included in the British Mountaineering Council guidebook. Although