St. Dunstan's Well Catchment is a geological Site of Special Scientific Interest, covering 39.8 hectares (98.3 acre) near Stoke St Michael

Stoke St Michael

Stoke St Michael is a village and civil parish on the Mendip Hills north east of Shepton Mallet, and west of Frome, in the Mendip district of Somerset, England.-History:...

 in the Mendip Hills

Mendip Hills

The Mendip Hills is a range of limestone hills to the south of Bristol and Bath in Somerset, England. Running east to west between Weston-super-Mare and Frome, the hills overlook the Somerset Levels to the south and the Avon Valley to the north...

, Somerset

Somerset

The ceremonial and non-metropolitan county of Somerset in South West England borders Bristol and Gloucestershire to the north, Wiltshire to the east, Dorset to the south-east, and Devon to the south-west. It is partly bounded to the north and west by the Bristol Channel and the estuary of the...

, notified in 1967.

Formerly known as Stoke St Michael Slocker.

Geological

St Dunstan's Well Catchment is an important and well-known cave system which includes a series of spectacularly-decorated caves which in total extend to about 4 miles of mapped passage. The caves at Fairy Cave Quarry

Fairy Cave Quarry

Fairy Cave Quarry is between Stoke St Michael and Oakhill in the limestone of the Mendip Hills, in Somerset, England.Quarrying was first started on the site in the early 1920s. In 1963 the quarry was acquired by Hobbs Ltd., and production on a much larger scale began...

 were formed mainly by the erosive action of
water flowing beneath the water-table at considerable pressure (so called 'phreatic

Phreatic

The term phreatic is used in Earth sciences to refer to matters relating to ground water below the water table . The term 'phreatic surface' indicates the location where the pore water pressure is under atmospheric conditions...

' development), but as the water table has fallen many of the caves now lie well above it and the system now contains a variety of cave formations (stalagmite

Stalagmite

A stalagmite is a type of speleothem that rises from the floor of a limestone cave due to the dripping of mineralized solutions and the deposition of calcium carbonate. This stalagmite formation occurs only under certain pH conditions within the underground cavern. The corresponding formation on...

s, stalactites and calcite

Calcite

Calcite is a carbonate mineral and the most stable polymorph of calcium carbonate . The other polymorphs are the minerals aragonite and vaterite. Aragonite will change to calcite at 380-470°C, and vaterite is even less stable.-Properties:...

 curtains) which in their extent and preservation are amongst the best in Britain. Shatter Cave

Shatter Cave

Shatter Cave is a cave in Fairy Cave Quarry, near Stoke St Michael in the limestone of the Mendip Hills, in Somerset, England. It falls within the St...

 and Withyhill Cave are generally considered to be amongst the finest decorated caves in Britain in terms of their sheer abundance of pure white and translucent calcite deposits.

Biological

An area of nationally rare species-rich unimproved calcareous grassland of the Sheep's-fescue-Meadow Oat-grass type occurs in the field to the east of Stoke Lane Quarry. Small numbers of Greater Horseshoe Bat

Greater Horseshoe Bat

The Greater Horseshoe Bat is a European bat of the Rhinolophus genus. Its distribution covers Europe, Africa, South Asia and Australia. It is the largest of the European Horseshoe Bats and is thus easily distinguished from other species...

 (Rhinolophus ferrumequinum), Lesser Horseshoe Bat

Lesser horseshoe bat

The Lesser Horseshoe Bat , is a type of European bat related to but smaller than its cousin, the Greater Horseshoe Bat...

 (Rhinolophus hipposideros) and Natterer's bat

Natterer's bat

Natterer's bat is a European bat with pale wings. It has brown fur, also seen on the leg wing membrane, tending to white on its underside...

(Myotis nattereri) hibernate in the cave system.