Caves of the Mendip Hills then rising up a fracture in the rock. Few caves on the Mendip Hills are more than deep or a few kilometres in length, (with some notable exceptions, such as Swildon's Hole which is over long), but a number are complex with several levels of passages which have been abandoned by the water, for example those around Cheddar. The catchment area of the Cheddar Yeo, which rises in Gough's Cave, measures . Dye marking shows that some of the water travels underground for up to , taking up to 14 days to reach Cheddar. When Banwell Bone Cave was discovered
Cave Diving Group Neath River Cave. Progress and development of equipment and techniques have always come in phases, and with this progress, although still hoping to discover dry caves, came diving of a purely exploratory nature. This has led to advances at Wookey Hole and Cheddar Gorge caves in Somerset. In Derbyshire a great deal of effort has produced significant discoveries in the Peak Cavern/Speedwell Cavern system. In South Wales many kilometres of Daren Cilau were first trodden by cave divers; and the link with Elm Hole and Pwll y Cwm was another major feat. In the north of England, divers have made