Priddy Pools () is a geological Site of Special Scientific Interest at Priddy in the Mendip Hills, Somerset, notified in 1972. The pools provided the water supply for the Priddy Mineries which is now a Nature Reserve. Biological This site supports a very rich invertebrate and amphibian fauna. A wide range of seminatural habitats are present, including valley mire, open water, swamp and tall fen. These habitats have a restricted distribution in the Mendip Hills. Priddy Pools is situated in the central Mendip lead orefield and the ecology of the area bears the mark of the lead industry. The northern pool was dammed in the 1850s to provide a supply of running water for the sifting and washing of slag. Lead was processed at St Cuthbert's Works until 1908. The hydrology of the site is complex. Nutrient-poor water flows from springs in the north of the site to St Cuthbert's Swallet where it disappears before re-emerging at Wookey Hole. A valley mire has developed in the area immediately to the south of the springs. Sphagnum recurvum and Sphagnum auriculatum are the most frequent mosses, and a range of higher plants can be found. Additional interest lies in the flora that can tolerate high concentrations of lead in the soil such as spring sandwort (Minuartia verna) and the moss Ditrichum plumbicola. Priddy Pools supports a very rich fauna. Fifteen species of dragonfly have been recorded; as well as supporting the only population of downy emerald in the Mendips, the site hosts the notable four-spotted chaser (Libellula quadrimaculata) and ruddy darter (Sympetrum sanguineum). Five British species of amphibian occur and there are good populations of great crested newt (Triturus cristatus), smooth newt (Triturus vulgaris) and palmate newt (Triturus helveticus). Three species of reptile, viviparous lizard (Lacerta vivipara), adder (Vipera berus), grass snake (Natrix natrix), and at least two species of fish; European perch, (Perca fluviatilis) and three-spined stickleback (Gasterosteus aculeatus) are present. Breeding birds include moorhen (Gallinula chloropus), coot (Fulica atra), mallard (Anas platyrhynchos), reed bunting (Emberiza schoeniclus) and sedge warbler (Acrocephalus schoenobaenus). Priddy Pools is an important research site. Detailed study of the algae in the northern pool was carried out in the late 1960s and early 1970s, as part of the International Biological Programme. Geological The site contains the entrance to St Cuthbert's Swallet cave, and overlies a large part of the cave complex reached through St Cuthbert's Swallet. This