Caves of the Mendip Hills Caves of the Mendip Hills The caves of the Mendip Hills are formed by the particular geology of the Mendip Hills: large areas of limestone worn away by water makes it a national centre for caving. The hills conceal the largest underground river system in Britain. The hills consist of anticlines of Carboniferous Limestone lying over Devonian Old Red Sandstone, with the sandstone exposed on the summits. When a surface stream running off the sandstone reaches the limestone it sinks below ground through a "swallet", (also known locally as a "slocker"), continuing on its way down towards sea level by
Cheddar Gorge gorge are owned by The National Trust. Every year both of the gorge's owners contribute funds towards the clearance of scrub bush and trees from the area. Most of the commercial visitor activity in the gorge is on the Longleat-owned south side, including access to the two main commercial show caves and the visitor centre, which is operated by Longleat-owned company "Cheddar Gorge and Caves Ltd" under director Hugh Cornwell. Due to the fact that tourist numbers have dropped through the show caves from 400,000 a year in the 1980s to 150,000, in 2013 Ceawlin Thynn, Viscount Weymouth who runs