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 cheese cut into cubes to drain the whey, and then stacked and turned. Strong, extra-mature Cheddar, sometimes called vintage, needs to be matured for 15 months or more. The cheese is kept at a constant temperature, often requiring special facilities. As with other hard cheese varieties produced worldwide, caves provide an ideal environment for maturing cheese; still, today, some Cheddar cheese is matured in the caves at Wookey Hole and Cheddar Gorge. Additionally, some versions of Cheddar cheese are smoked. The ideal quality of the original Somerset Cheddar was described by Joseph Harding in 1864 as "close and firm in texture,