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 gate servicing the paper mill was built about 1852. The tunnel excavated from the third chamber to the ninth chamber and then out to daylight was dug in 1974–1975 by ex-coal miners from the Radstock area. The show cave was further extended in 2015 by excavating a tunnel from the ninth chamber to the 20th chamber. The constant temperature of in the caves is used by Ford Farm of Dorset to mature Cheddar cheese in the 'Cheese Tunnel' – an excavated side tunnel between the ninth chamber and the exit to the show cave. Archaeological investigations were undertaken from 1859