Geography of Somerset

From Wikipedia, the free encyclopedia
Jump to: navigation, search
Somerset shown (in red) amongst the counties of England.

The county of Somerset is in South West England, bordered by the Bristol Channel and the counties of Bristol and Gloucestershire to the north, and Wiltshire to the east, Dorset to the south, and Devon to the west. The climate is influenced by the proximity of the county to the Atlantic Ocean and the prevailing westerly winds; thus it tends to be mild, damp and windy.

Somerset is predominantly a rural and agricultural county. The main upland areas are the Mendip Hills in the east and the Quantock Hills further west, the Blackdown Hills form the county's southern border, and Exmoor is on the western fringes. Between the Mendips and the Quantocks is the large area of level, low-lying ground known as the Somerset Levels. The county's main rivers flow northwestward through the levels into the Bristol Channel.

The landscape of Somerset is largely determined by the underlying geology. The Carboniferous Limestone that forms the Mendips has been eroded to form gorges and caves. Exmoor is an extensive area of moorland and a National Park and the Somerset Levels contains wetland areas of international importance for birds. Both the Quantocks and the Blackdown Hills are Areas of Outstanding Natural Beauty, and the island of Steep Holm, in the Bristol Channel, is one of many Sites of Special Scientific Interest. The M5 motorway runs diagonally across the county, which is also served by a network of trunk roads. Several railway lines provide services to other parts of the United Kingdom, and Bristol Airport is located in the northeast. Some of the industries traditionally based in the county have declined, but it is popular with tourists and still famed for its Cheddar cheese and cider.

Physical geography[edit]

Somerset is a rural county in the southwest of England with a total area of 4,171 square kilometres (1,610 sq mi). It is bounded on the north-west by the Bristol Channel, on the north by Bristol and Gloucestershire, on the east by Wiltshire, on the south-east by Dorset, and on the south west and west by Devon. The countryside divides into four main geological regions, spanning the Silurian, the Devonian and the Carboniferous to the Permian, and these influence the landscape. The central part of the county has broad, level plains and there are several ranges of low hills.[1]

The Somerset Levels and surrounding hills

The north coast of Somerset is gently shelving with low cliffs and long stretches of sandy beach, some sections of which, especially in the northwest, are muddy. The principal coastal feature is Bridgwater Bay, and the only important harbours are at the mouths of the main rivers, the Avon and the Parrett. The other main rivers flowing northwards and westwards into the Bristol Channel are the Axe, Exe, Brue and Congresbury Yeo. The main upland areas in the county are the Mendip Hills in the northeast and the Quantock Hills further west; the Quantocks extend northwards from near Taunton to the coast where they terminate in Wills Neck; the Mendips extend from Frome westwards to the eastern end of Bridgewater Bay, and culminate in the promontory of Brean Down, only to crop up again in the Bristol Channel as the islands of Steep Holm and Flat Holm. The Blackdown Hills form the southerly border of the county with North Devon, and Exmoor is an elevated expanse of moorland on the western border of the county with North Devon.[1]

Near the coast, halfway between the Quantocks and the Mendips, and lying parallel to them, is a low ridge, the Polden Hills. On either side of this is a coastal plain and wetlands area known as the Somerset Levels, much of which is a mere 6 m (20 ft) above sea level. The northeasterly part of the Levels is drained by the Axe and Brue, and the southwesterly part by the Parrett and its main tributary, the Tone. This part has traditionally been known as Sedgemoor, and to the east of it is Glastonbury Tor, an isolated hill projecting from the low-lying plain.[1]

The highest points in Somerset are on Exmoor with Dunkery Beacon (520m) being the county top.[2] The main centres of population are Bath, Wells, Taunton, which is the county town, Weston-super-Mare, Bridgwater, Yeovil, Frome and Glastonbury.[1]


Main article: Geology of Somerset

The oldest rocks in Somerset are of Silurian age (443–419 million years ago). They make up a sequence of lavas, tuffs (volcanic ash), shales and mudstones in a narrow outcrop to the northeast of Shepton Mallet, in the eastern Mendip Hills.[3] Rocks from the Devonian (419–359 million years ago) are found across much of Exmoor,[4] the Quantocks, and in the cores of the folded masses that form the Mendip Hills.[5]

The Cheddar Gorge was carved by water

Carboniferous Period (359–299 million years ago) rocks are represented by the Carboniferous Limestone that forms the Mendip Hills, rising abruptly out of the flat landscape of the Somerset Levels. The limestones are full of fossils of crinoids (sea-lilies), corals and brachiopods, and provide evidence of the abundant marine life that existed in the shallow tropical seas that covered these areas at that time.[6] The secondary shaping process that has taken place over many millennia is the action of rainfall on the peaks of the Limestone depositions forming the majority of the underlying rock stratas. Some of the hill ranges, such as the Mendips, can extend to heights in excess of 800 feet (240 m) above sea level, and from these flow rivers of substantial erosive power. Examples of this erosion may be seen at Cheddar Gorge and the caves within it, where the soft limestone has been scoured into gorges and caverns of great depth and length.[6] At the end of the Permian (299–252 million years ago) and Triassic periods (252–201 million years ago), the Variscan orogeny resulted in the uprising of several mountainous areas including Dartmoor to the south, Exmoor, the Quantocks and the Mendips.[5]

Much of the landscape of Somerset falls into types determined by the underlying geology. These landscapes are the limestone karst and lias of the north, the clay vales and wetlands of the centre, the oolites of the east and south, and the Devonian sandstone of the west.[7] To the north-east of the Somerset Levels, the Mendip Hills are moderately high limestone hills. The central and western Mendip Hills was designated an Area of Outstanding Natural Beauty in 1972 and covers 198 km2 (76 sq mi). The main habitat on these hills is calcareous grassland, with some arable agriculture. The Somerset Coalfield is part of a larger coalfield which stretches into Gloucestershire. To the north of the Mendip hills is the Chew Valley and to the south, on the clay substrate, are broad valleys which support dairy farming and drain into the Somerset Levels.[8]


Along with the rest of South West England, Somerset has a temperate climate which is generally wetter and milder than most of England.[9] The annual mean temperature is approximately 10 °C (50 °F). Seasonal temperature variation is less extreme than most of the United Kingdom because of the moderating influence of the adjacent areas of sea. The summer months of July and August are the warmest with mean daily maxima of approximately 21 °C (70 °F). In winter mean minimum temperatures of 1 °C (34 °F) or 2 °C (36 °F) are common.[9] In the summer the Azores high pressure system affects the south-west of England, but convective cloud sometimes forms inland, reducing the number of hours of sunshine. Annual sunshine rates are slightly less than the regional average of 1,600 hours.[9] Most of the rainfall in autumn and winter is caused by the arrival of Atlantic depressions, which bring moisture-laden air from the southwest and west. In summer, a large proportion of the rainfall is caused by sunlight heating the ground, leading to convection and the formation of showers and thunderstorms. Average rainfall is around 700 mm (28 in), and eight to fifteen days of snowfall is typical. November to March have the highest mean wind speeds, and June to August the lightest winds. The predominant wind direction is from the south-west.[9]

Early settlement[edit]

In much of the area bordering the wetlands, an abundance of produce, of great variety, can be easily cultivated. The green and varied landscape also offers good grazing for livestock. In some areas the carboniferous limestone and the Dolomitic Conglomerate have been mineralised with lead and zinc ores. Evidence of early settlement comes from the Sweet Track, which was built from timber felled in the winter of 3807-06 BC,[10] and lowland villages such as Glastonbury Lake Village and hill forts and ancient settlements on hills, many of which date from the Iron Age. From the time of the Romans until 1908, the Mendip Hills were an important source of lead.[11] These areas were the centre of a major mining industry; this is reflected in areas of contaminated rough ground known locally as "gruffy". The word "gruffy" is thought to derive from the grooves that were formed where the lead ore was extracted from veins near the surface.[12] Calamine, manganese, iron, copper and barytes were also mined.[13]

Many hillsides, such as Cadbury Castle, Ham Hill and Maes Knoll, and also sheltered valleys offered defensible locations for early human settlements. Trade was established early. The large tidal variation provided access well inland, and was a key factor in distributing goods and produce, using rivers such as the Parrett and Avon.[14][15] The tidal range of 43 feet (13 m),[16] is second only to Bay of Fundy in Eastern Canada.[17][18]

Land use[edit]

Somerset is a predominantly agricultural county with arable cropping and dairy farming; Cheddar cheese is one of the well-known products. The main field crops include wheat, barley, oats and root crops, and there are extensive orchards producing cider apples. There are large numbers of cattle and sheep in the county, and Exmoor ponies and red deer roam on the open moorland in the west of the county.[1] Coal was at one time abundant in the county; the Somerset Coalfield stretched from Cromhall in the north to the Mendips in the south, and from Nailsea in the west to Bath in the east. The last two pits, at Kilmersdon and Writhlington, closed in 1973.[19] Minerals that were mined here at one time included iron, lead, zinc, slate and fuller's earth.[1]

The Mendips are the most southerly Carboniferous limestone uplands in Britain. They are composed of three major anticlinal structures, each with a core of older Devonian sandstone and Silurian volcanic rocks. The limestone is quarried for building stone and the other rocks for use in road construction and as a concrete aggregate. Sand, gravel and peat are extracted from other parts of the county.[20]

The Somerset Levels between the ancient towns of Glastonbury and Wells have traditionally been used for growing withies, flexible, strong willow stems, used for many centuries by local inhabitants for making furniture, baskets and fencing. Willow has been cut, processed and used on the Levels since humans moved into the area.[21] Fragments of willow basket were found near the Glastonbury Lake Village, and it was also used in the construction of several Iron Age causeways.[22] This ancient industry still thrives in these preserved areas of wetlands, and there is a Willows and Wetlands Visitor Centre at Stoke St Gregory.[21]

Besides farming and its associated industries, including the making of cider, cheese and yoghurt, and the extraction of peat, the county has little industry. It has traditionally been involved in the manufacture of helicopters, some heavy industries related to defence, quarrying and the mining of gravels and sands, brick-making and tile-making, and the manufacture of slippers, boots and shoes, but many of these industries have declined.[1] These days, tourism is one of the main sources of income.[23]

Protected areas[edit]

Deer in Exmoor National Park

The Gordano Valley west of the Port of Bristol stretches past the coastal towns of Portishead and Clevedon. It has been designated as a National nature reserve,[24] and much of it may be observed by travellers on the south bound M5 motorway. The Chew Valley is another example of managed water ways and woodland in the same area. The Avon Valley to the East of Bristol continues through to Bath and beyond toward the county of Wiltshire. The Blackdown Hills were designated an Area of Outstanding Natural Beauty (AONB) in 1991,[25] and the Quantock Hills have held the status since 1956, the first such designation in England under the National Parks and Access to the Countryside Act 1949.[26]

The Somerset Levels is a wetland area of international importance, with large numbers of wading birds overwintering there.[21]

Exmoor is a National Park which straddles two counties with 71% of the park being located in Somerset and 29% located in Devon. The total area of the park, which includes the Brendon Hills and the Vale of Porlock, covers 692.8 square kilometres (267.5 sq mi) of hilly open moorland and includes 55 kilometres (34 mi) of coastline.[27]

Steep Holm is protected as a nature reserve and Site of Special Scientific Interest (SSSI). [28] A large number of sea bird are resident or visit the island, particularly European herring gulls (Larus argentatus) and Lesser black-backed gulls (Larus fuscus),[29] but it is mainly preserved for its botanical interest; it is the only site in the United Kingdom where wild peonies grow.[30]

Local government[edit]

The ceremonial county of Somerset is subdivided into five districts and two unitary authority areas (whose councils combine the functions of a county and a district). The five districts are West Somerset, South Somerset, Taunton Deane, Mendip and Sedgemoor, and the two unitary authorities are North Somerset and Bath & North East Somerset.[31]


Bristol Airport is located in North Somerset

Somerset has approximately 6,530 km (4,060 mi) of roads.[32] The M5 motorway runs diagonally across the county, from northeast to southwest. Other main arterial routes include the A39, the A303, the A37, the A38, the A358 and the A361,[33] but many rural villages can only be accessed via narrow country lanes.[32]

Rail services are provided by the West of England Main Line, linking London Waterloo and Basingstoke to Exeter through Yeovil Junction, and the Bristol to Exeter Line, part of the Great Western Main Line. The Heart of Wessex Line which runs from Bristol Temple Meads to Weymouth, and the Reading to Taunton Line serve other parts of the county. The key train operator for Somerset is First Great Western, and other services are provided by South West Trains and CrossCountry. The West Somerset Railway, which links Bishops Lydeard and Minehead, is the longest heritage railway in England.[34] Bristol Airport, located beside the A38 in North Somerset, provides national and international air services.[33]


  1. ^ a b c d e f g E. F. Bozman, ed. (1967). "11: Santa Catarina - Thomas à Kempis". Everyman's Encyclopedia. J. M. Dent & Sons. pp. 295–296. 
  2. ^ "Exmoor National Park Facts and Figures". Exmoor National Park. Retrieved 12 September 2016. 
  3. ^ Roche, David (2004). "Moons Hill Quarry, Stoke St Michael, Shepton Mallet". Geodiversity Audit of Active Aggregate Quarries. Somerset County Council. Retrieved 12 August 2008. 
  4. ^ "Geology of Exmoor". Everything Exmoor. Retrieved 21 August 2008. 
  5. ^ a b Hardy, Peter (1999). The Geology of Somerset. Ex Libris. ISBN 978-0-948578-42-7. 
  6. ^ a b P. W. Scott; Colin Malcolm Bristow; Geological Society of London (2002). Industrial Minerals and Extractive Industry Geology. Geological Society of London. pp. 363–364. ISBN 978-1-86239-099-7. 
  7. ^ "Somerset Geology". Good Rock Guide. Retrieved 22 November 2009. 
  8. ^ "Frequently Asked Questions". Mendip Hills AONB. Retrieved 15 September 2016. 
  9. ^ a b c d "South West England: climate". Met Office. Retrieved 26 May 2015. 
  10. ^ "The day the Sweet Track was built". New Scientist, 16 June 1990. Retrieved 26 October 2007. 
  11. ^ Toulson, Shirley (1984). The Mendip Hills: A Threatened Landscape. London: Victor Gollancz. ISBN 0-575-03453-X. 
  12. ^ Coysh, A.W.; Mason, E.J.; Waite, V. (1977). The Mendips. London: Robert Hale Ltd. ISBN 0-7091-6426-2. 
  13. ^ Gough, J.W. (1967). The mines of Mendip. David & Charles. 
  14. ^ Edited by William Page (1992). Dunning, R. W., ed. Andersfield, Cannington, and North Petherton Hundreds (Bridgwater and Neighbouring Parishes). The Victoria History of the County of Somerset. VI. Oxford: Oxford University Press for the University of London Institute of Historical Research. ISBN 0-19-722780-5. 
  15. ^ Fitzhugh, Rod (1993). Bridgwater and the River Parrett: in old photographs. Alan Sutton Publishing. ISBN 0-7509-0518-2. 
  16. ^ "Severn Estuary Barrage". UK Environment Agency. 31 May 2006. Archived from the original (PDF) on 30 September 2007. Retrieved 3 September 2007. 
  17. ^ Chan, Marjorie A.; Archer, Allen William (2003). Extreme Depositional Environments: Mega End Members in Geologic Time. Boulder, Colorado: Geological Society of America. p. 151. ISBN 0-8137-2370-1. 
  18. ^ "Coast: Bristol Channel". BBC. Retrieved 27 August 2007. 
  19. ^ "A Brief History of the Bristol and Somerset Coalfield". The Mines of the Bristol and Somerset Coalfield. Retrieved 9 September 2016. 
  20. ^ "Somerset Minerals Plan". Somerset County Council. Retrieved 10 September 2016. 
  21. ^ a b c "Willows and Wetlands Visitor Centre". Visit Somerset. Retrieved 9 September 2016. 
  22. ^ "Somerset Levels". BBC Radio 4 - Open Country. Retrieved 10 June 2007. 
  23. ^ "Employers in Somerset". Somerset Chamber of Commerce. Archived from the original on 9 April 2006. Retrieved 12 September 2016. 
  24. ^ "Gordano Valley NNR". Natural England. Retrieved 31 January 2010. 
  25. ^ "What is an AONB". Blackdown Hills AONB. Retrieved 13 May 2008. 
  26. ^ "Welcome to the Quantock Hills AONB Service Website". Quantock Hills AONB. Somerset County Council. Retrieved 11 April 2008. 
  27. ^ "Moor Facts". 19 October 1954. Retrieved 1 August 2009. 
  28. ^ "Citation – Steep Holm" (PDF). English Nature. Retrieved 6 September 2007. 
  29. ^ Lewis, Stanley (1936). "Birds of the Island of Steep Holm" (PDF). British Birds. xxx: 219–223. 
  30. ^ "Steep Holm Island, Somerset". The Wildlife Trusts. Retrieved 12 September 2016. 
  31. ^ "The Avon (Structural Change) Order 1995". HMSO. Retrieved 10 September 2016. 
  32. ^ a b "About The Service". Devon and Somerset Fire and Rescue. Archived from the original on 23 June 2010. Retrieved 10 September 2016. 
  33. ^ a b AA Concise Road Atlas of Britain. AA Publishing. 2016. pp. 16–17. ISBN 978-0-7495-7743-8. 
  34. ^ "West Somerset Railway". Visit Somerset. Retrieved 10 September 2016.