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 Complex calcareous dry dwarf-shrub heath, semi-natural broadleaved woodland and dense and scattered scrub. Four nationally rare plants are present, including Little Robin "Geranium purpureum", Cheddar Pink "Dianthus gratianopolitanus" and Cheddar Bedstraw "Galium fleurotii", two of which are endemic to the Cheddar area, as well as fifteen nationally scarce species. This site is important for karst, caves and vertebrate palaeontology and comprises four single interest localities. Cheddar Gorge is Britain’s largest gorge and probably the country’s best known limestone feature. It is a spectacular fluvial feature with a geomorphic history extending back 2 million years and encompassing the major environmental changes of