Writhlington SSSI () is a 0.5

hectare The hectare (; SI symbol: ha) is a non-SI metric unit of area equal to a square with 100-metre sides (1 hm2), that is, square metres (), and is primarily used in the measurement of land. There are 100 hectares in one square kilometre. ...

geological Site of Special Scientific Interest A Site of Special Scientific Interest (SSSI) in Great Britain, or an Area of Special Scientific Interest (ASSI) in the Isle of Man and Northern Ireland, is a conservation designation denoting a protected area in the United Kingdom and Isle ...

near the town of

Radstock Radstock is a town and civil parish on the northern slope of the Mendip Hills in Somerset, England, about south-west of Bath and north-west of Frome. It is within the area of the unitary authority of Bath and North East Somerset. The Radsto ...

Bath and North East Somerset Bath and North East Somerset (B&NES) is a Unitary authorities of England, unitary authority district in Somerset, South West England. Bath and North East Somerset Council was created on 1 April 1996 following the abolition of the county of Avon. ...

, notified in 1992. This is the site of old mine workings on the

Somerset coalfield The Somerset Coalfield in northern Somerset, England is an area where coal was mined from the 15th century until 1973. It is part of a larger coalfield which stretched into southern Gloucestershire. The Somerset coalfield stretched from Cromh ...

, including 3,000 tons of Upper Carboniferous

spoil Spoil or spoils may refer to: * Spoils, the proceeds of looting taken from an enemy or victim * Overburden, or spoil, the material that lies above an area that lends itself to economical exploitation * Spoil, material removed by earthworks * Spoi ...

from which more than 1,400 insect fossil specimens have been recovered, including the world's earliest known

Damselfly Damselflies are flying insects of the suborder Zygoptera in the order Odonata. They are similar to dragonflies (which constitute the other odonatan suborder, Epiprocta) but are usually smaller and have slimmer bodies. Most species fold the win ...

. It is a

Geological Conservation Review The Geological Conservation Review (GCR) is produced by the UK's Joint Nature Conservation Committee. It is designed to identify those sites of national and international importance needed to show all the key scientific elements of the geological ...

Site, because it has yielded the largest ever collection of

Carboniferous The Carboniferous ( ) is a Geologic time scale, geologic period and System (stratigraphy), system of the Paleozoic era (geology), era that spans 60 million years, from the end of the Devonian Period Ma (million years ago) to the beginning of the ...

insects in Britain. The commonest forms belong to the order

Blattodea Blattodea is an order (biology), order of insects that contains cockroaches and termites. Formerly, termites were considered a separate order, Isoptera, but genetics, genetic and molecular evidence suggests they evolved from within the cockroach ...

(cockroaches) and include the extinct families Archimylacris and

Mymarommatidae The Mymarommatidae, sometimes referred to as false fairy wasps, are a very small family of microscopic parasitic wasps. Only about half of the known species are living taxa (the others are fossils), but they are found worldwide.Gibson, G.A.P.; Re ...

. Protorthoptera and

Palaeodictyoptera The Palaeodictyoptera are an extinct order of medium-sized to very large, primitive Palaeozoic paleopterous insects. They are informative about the evolution of wings in insects. Overview They were characterized by beak-like mouthparts, used ...

also occur. Frequent

chelicerates The subphylum Chelicerata (from Neo-Latin, , ) constitutes one of the major subdivisions of the phylum Arthropoda. Chelicerates include the sea spiders, horseshoe crabs, and arachnids (including harvestmen, scorpions, spiders, solifuges, tic ...

(arthropods) include trace and body fossils of xiphosurid merostomes and arachnids, including Phalangiotarbida and

Trigonotarbida The order Trigonotarbida is a group of extinct arachnids whose fossil record extends from the late Silurian to the early Permian ( Pridoli to Sakmarian).Dunlop, J. A., Penney, D. & Jekel, D. 2020A summary list of fossil spiders and their relative ...

and also true spiders (Araneida). Rare

myriapods Myriapods () are the members of subphylum Myriapoda, containing arthropods such as millipedes and centipedes. The group contains about 13,000 species, all of them terrestrial. Although molecular evidence and similar fossils suggests a diversifi ...

(millipedes) and occasional

conchostracan Clam shrimp are a group of bivalved branchiopod crustaceans that resemble the unrelated Bivalvia, bivalved molluscs. They are extant and also known from the fossil record, from at least the Devonian period and perhaps before. They were originally ...

crustaceans (clam-shrimps) also occur.English Nature citation sheet for the site
(accessed 17 July 2006)

References

{{SSSIs Avon geological Sites of Special Scientific Interest in Avon Radstock Sites of Special Scientific Interest notified in 1992 Somerset coalfield