Reservoir Hole high and long. Prior to the discovery, the largest void under the Mendip Hills was thought to be "Main Chamber" in GB Cave, which is high. Before the find in 2012, the cave was already noted for a number of fine formations, and the newly discovered chamber, which has been named “The Frozen Deep”, contains pure-white pillars tall, as well as many stalagmites and stalactites. The possibility of a connection between Reservoir Hole and Gough's Cave, one of the show caves in Cheddar Gorge, has been raised, as the two caves are in close proximity. The stream in Reservoir Hole
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