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
Wookey Hole Caves river are used in a handmade paper mill, the oldest extant in Britain, which began operations circa 1610. The low, constant temperature of the caves means that they can be used for maturing Cheddar cheese. The caves are the site of the first cave dives in Britain which were undertaken by Jack Sheppard and Graham Balcombe. Since the 1930s divers have explored the extensive network of chambers developing breathing apparatus and novel techniques in the process. The full extent of the cave system is still unknown with approximately , including 25 chambers, having been explored. Part of the cave system