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
Cheddar, Somerset restricted distribution in the south of England, and the soldier beetle "Cantharis fusca" also occur. By far the largest of the SSSIs is called Cheddar Complex and covers of the gorge, caves and the surrounding area. It is important because of both biological and geological features. It includes four SSSIs, formerly known as Cheddar Gorge SSSI, August Hole/Longwood Swallet SSSI, GB Cavern Charterhouse SSSI and Charterhouse on-Mendip SSSI. It is partly owned by the National Trust who acquired it in 1910 and partly managed by the Somerset Wildlife Trust. Close to the village and gorge are Batts Combe quarry and