Cheddar Complex the Pleistocene period. Cheddar Caves contain both active and fossil systems. The active cave system is one of the most heavily studied karst systems in Britain with reference to the conduit and diffuse flow characteristics of its hydrology. Charterhouse Caves include four major swallet caves that provide an indisputable record of Pleistocene landform development in the Mendips and surrounding area. Sun Hole Cave provides a varied fauna radiocarbon-dated to the end of the Late Devensian Cold Stage. Several types of limestone including Clifton Down Limestone, Cheddar Limestone and Cheddar Oolite are visible in the Gorge and surrounding areas with pale
Wookey Hole Caves in 1989. A collection of fairground art of Wookey Hole was sold in 1997 at Christie's. The present owner is the former circus proprietor Gerry Cottle, who has introduced a circus school. The cave was used for the filming of episodes of the BBC TV series "Doctor Who": the serial "Revenge of the Cybermen" (1975) starring Tom Baker. This has since been referenced in the comedy of "The League of Gentlemen". The cave was also used in the filming of the British series "Blake's 7" (1978) and "Robin of Sherwood" (1983). The caves were used again for "Doctor Who" in