cave is an integral part of the Priddy Caves system which contains over 10 miles of surveyed cave passages divided between two major systems and four minor systems, all interconnected. All the caves are sink hole systems, fed by sink holes at the ground surface, and 3 of them exceed 100 metres in depth; in all the caves the detailed disposition and form of the passages can be seen clearly to have followed marked lines of natural weakness in the rocks. St Cuthbert's Swallet was formed by the erosive action of water flowing beneath the water-table at considerable depth (so called "phreatic development"). St Cuthbert's Swallet is a classic example of a deep phreatic cave system, containing inclined bedding plane mazes at many levels, fault-guided rifts and some significant chambers. Nine successive phases of sediment deposition, stalagmite deposition and stream erosion have been recognised in St Cuthbert's Swallet, providing an exceptional record of environmental change through the warm and cold phases of the Ice Age. Use in literature In his 1995 book "Our Game", John le Carré uses "Priddy Pool" as the site for the drowning of one of his characters. References External links Priddy Caves in GCR database Bristol Exploration Club Mendip Hills Sites of Special Scientific Interest in Somerset Sites of Special Scientific Interest notified in 1972 Wetland Sites of Special Scientific Interest Geology of Somerset