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
Ebbor Gorge (1:50,000 sheet 280, Wells). An example of the rare mineral mendipite was found at the head of the gorge. A stream issuing to the west of the site runs down the tributary valley of Hope Wood before joining the main gorge. The original watercourse which may have cut the gorge into the limestone became diverted underground and now emerges at Wookey Hole Caves to form the River Axe. Various caves within the gorge were inhabited by neolithic people from which flint tools are held in the Wells and Mendip Museum. One particularly fine flint flake can be seen in the