Sleightholme Beck Gorge - The Troughs is a Site of Special Scientific Interest

Site of Special Scientific Interest

A Site of Special Scientific Interest is a conservation designation denoting a protected area in the United Kingdom. SSSIs are the basic building block of site-based nature conservation legislation and most other legal nature/geological conservation designations in Great Britain are based upon...

 in the Teesdale

Teesdale (district)

Teesdale was, from 1974 to 2009, a local government district in County Durham, England. Its council was based in Barnard Castle and it was named after the valley of the River Tees....

 district of south-west County Durham

County Durham

County Durham is a ceremonial county and unitary district in north east England. The county town is Durham. The largest settlement in the ceremonial county is the town of Darlington...

, England

England

England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...

. The site covers a gorge in the valley of Sleightholme Beck between the hamlet of Sleightholme

Sleightholme

Sleightholme is a secluded hamlet on a dead end road in County Durham, England. It lies beside Sleightholme Beck, a tributary of the River Greta. The nearest town is Bowes, 4 miles away....

 and the confluence with the River Greta

River Greta

The River Greta is a river in Cumbria, England. It is a tributary of the River Derwent and flows through the town of Keswick.The source of the river is to be found near to Threlkeld at the confluence of the River Glenderamackin and St. John's Beck...

, some 3 km upriver from the village of Bowes

Bowes

Bowes is a village in County Durham, England. Located in the Pennine hills, it is situated close to Barnard Castle. It is built around the medieval Bowes Castle.-Civic history:...

.

The site has both biological and geological interest and has been designated of national importance in the Geological Conservation Review

Geological Conservation Review

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

.

The gorge is incised through the Namurian

Namurian

The Namurian is a stage in the regional stratigraphy of northwest Europe with an age between roughly 326 and 313 Ma . It is a subdivision of the Carboniferous system or period and the regional Silesian series. The Namurian is named for the Belgian city and province of Namur where strata of this age...

 Great Limestone

Limestone

Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....

 and is of particular interest because beds of sandstone

Sandstone

Sandstone is a sedimentary rock composed mainly of sand-sized minerals or rock grains.Most sandstone is composed of quartz and/or feldspar because these are the most common minerals in the Earth's crust. Like sand, sandstone may be any colour, but the most common colours are tan, brown, yellow,...

 in the middle of the section show structures characteristic of a shoreline, with the features of a river delta

River delta

A delta is a landform that is formed at the mouth of a river where that river flows into an ocean, sea, estuary, lake, reservoir, flat arid area, or another river. Deltas are formed from the deposition of the sediment carried by the river as the flow leaves the mouth of the river...

 and barrier bar.

The shallow soils that have developed on ledges and crevices in the limestone and on the scree

Scree

Scree, also called talus, is a term given to an accumulation of broken rock fragments at the base of crags, mountain cliffs, or valley shoulders. Landforms associated with these materials are sometimes called scree slopes or talus piles...

 slopes support a vegetation in which ferns such as maidenhair spleenwort, Asplenium trichomanes

Asplenium trichomanes

Asplenium trichomanes is a small fern in the spleenwort genus Asplenium. It is a widespread and common species, occurring almost worldwide in a variety of rocky habitats. It is a variable fern with several subspecies.-Description:It grows in tufts from a short rhizome...

, green spleenwort, A. viride

Asplenium viride

Asplenium viride is known as the green spleenwort because of its green stipes and raches. This feature easily distinguishes this species from the very similar-looking maidenhair spleenwort, Asplenium trichomanes.-Nomenclature:...

, and brittle bladder fern, Cystopteris fragilis

Cystopteris fragilis

Cystopteris fragilis is a species of fern known by the common names brittle bladderfern and common fragile fern. It can be found worldwide, generally in shady, moist areas. The leaves are up to 30 or 40 centimeters long and are borne on fleshy petioles. Each leaf is divided into many pairs of...

, are prominent. Woodland plants such as wood sorrel, Oxalis acetosella, wood millet, Milium effusum

Milium effusum

Milium effusum L. is a species of grass in the Poaceae family, native to damp forests of the Holarctic Kingdom.-External links:*...

, and dog's mercury, Mercurialis perennis, have established themselves in the shadier crevices, while rue-leaved saxifrage, Saxifraga tridactylites

Saxifraga tridactylites

Saxifraga tridactylites, the Rue-leaved Saxifrage or "nailwort", is a species of plant in the family Saxifragaceae....

, shining cranesbill Geranium lucidum

Geranium lucidum

Geranium lucidum, commonly known as Shining Cranesbill or Shining Geranium, is a herbaceous annual plant of the genus Geranium....

, and common whitlow grass, Erophila verna, occur in the most exposed situations. On the most inaccessible valley slopes, there is open woodland in which yew, Taxus baccata

Taxus baccata

Taxus baccata is a conifer native to western, central and southern Europe, northwest Africa, northern Iran and southwest Asia. It is the tree originally known as yew, though with other related trees becoming known, it may be now known as the English yew, or European yew.-Description:It is a small-...

, is abundant.

Dipper

White-throated Dipper

The White-throated Dipper , also known as the European Dipper or just Dipper is an aquatic passerine bird found in Europe, Middle East, Central Asia and the Indian Subcontinent. The species is divided into several subspecies, based primarily on colour differences, particularly of the pectoral band...

 and common sandpiper

Common Sandpiper

The Common Sandpiper is a small Palearctic wader. This bird and its American sister species, the Spotted Sandpiper , make up the genus Actitis. They are parapatric and replace each other geographically; stray birds of either species may settle down with breeders of the other and hybridize...

have been recorded from the site and probably breed in the area.