Cheddar Complex Cheddar Complex The Cheddar Complex is a 441.3 hectare (1090.5 acre) biological Site of Special Scientific Interest near Cheddar around the Cheddar Gorge and north east to Charterhouse in the Mendip Hills, Somerset, notified in 1952. The very large area includes 4 SSSIs formerly known as: Cheddar Gorge SSSI; August Hole/Longwood Swallet SSSI; GB Cavern Charterhouse SSSI; and Charterhouse on-Mendip SSSI. It is part owned by the National Trust, commercial landowners including the Marquess of Bath's Longleat Estate; and part managed by the Somerset Wildlife Trust. The Cheddar Complex supports a wide range of semi-natural habitats which includes unimproved grassland,
Wookey Hole Caves as an inlier at the centre. Wookey Hole is a solutional cave mainly formed in the limestone by chemical weathering whereby naturally acidic groundwater dissolves the carbonate rocks, but it is unique in that the first part of the cave is formed in Triassic Dolomitic Conglomerate, a well-cemented fossil limestone scree representing the infill of a Triassic valley. The cave was formed under phreatic conditions i.e. below the local water table, but lowering base levels to which the subterranean drainage was flowing resulted in some passages being abandoned by the river, and there is evidence of a number of abandoned