 By far the largest of the SSSIs is called Cheddar Complex and covers 441 @.@ 3 hectares ( 1 @,@ 090 @.@ 5 acres ) 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 . 
