Geography of Somerset

Somerset shown (in red) amongst the counties of England.

The county of Somerset is located in South West England, bordered by the Bristol Channel and the counties of Bristol and Gloucestershire to the north, and the counties of Wiltshire to the east, Dorset to the south, and Devon to the west.

Formation

Main article: Geology of Somerset

Somerset is in a natural "bowl" shaped section of South West England. Shaped over the ages by a mixture of tectonic plate motion, volcanic eruption, ice and water erosion. Much of the "bowls`" low lying land has been sculptured by wave action, a result of the unusually large tidal flow of the north coastal water (the Bristol Channel), and its neighbouring county of Gloucestershire's tidal river, the Severn. This tide is one of the largest rise and falls in Europe of some 39 feet (12 m) on average. 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. These depositions of many rock layers, a mixture of hard and soft rock types, and uplifting forces of volcanic activity give rise to the edges of the "bowl". Some of the hill ranges, such as the Mendips, can extend to heights in excess of 800 feet (240 m) above sea level in some parts of the county. This large height difference created past 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 varied shapes and caverns of great depth and length. The action of the (past) inland tides are the forces that shaped the extent of the lowlands (or wetlands) for which Somerset has become famous.

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. 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 squ 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.

Early settlement

The area bordered by the wetlands provides in the County of Somerset many locations where an abundance of produce, of great variety, can be easily cultivated. Its green and pleasantly 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. From the time of the Romans until 1908, the hills were an important source of lead. These areas were the centre of a major mining industry in the past and 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. Other commodities obtained included calamine, manganese, iron, copper and barytes.

Many hillsides, such as Cadbury Castle, Ham Hill and Maes Knoll and sheltered valleys offered defendable locations to early human settlements. Trade was established early in this part of England also, the unusual tide variation provided easy access well inland, and was a key factor in distributing goods and produce. Rivers that offered this facility included the Parrett and Avon.

Wild life areas

The Somerset Levels between the ancient towns of Glastonbury and Wells offer a haven to wildlife, these areas traditionally used for growing withies, a straight, strong and weavable plant, used for many centuries by local inhabitants for all manner of furniture, baskets and fencing. Willow has been cut and used on the Levels since humans moved into the area. Fragments of willow basket were found near the Glastonbury Lake Village, and it was also used in the construction of several Iron Age causeways. This ancient industry still thrives in these preserved areas of wetlands

The absence of any substantial population in this area allows a peaceful and unspoilt habitat to flourish. This land has to be maintained of course; for it to survive for any length of time. Over the centuries many land drainage channels have been dug to the sea and nearby rivers, and these have to be cleared constantly of any invasive plant growth.

Areas of outstanding natural beauty

The Gordano Valley west of the Port of Bristol stretches past the coastal towns of Portishead and Clevedon. Much of it may be observed by travellers on the South bound M5 Motorway. 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, 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.

Exmoor is a National Park which straddles two counties with 71% of the park 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 coast.

Coastal features

Many large shoreside areas are deposits of sand and gravel, brought down from the hills and nearby valleys. Some outcrops of hard rocks intersperce what is mainly a shallow drop to the sea. Off the coast of the town of Weston Super Mare are two hard rock formations. The island of Steep Holm is a wildlife sanctuary.

The changing face of Somerset

As population grows, and the needs of industry change, so does the face of Somerset. New areas of forestation are springing up, aided by Central Government grants. (refs reqd)These new areas offer a renewable timber resource and provide much needed shelter for local wildlife. The borders of the County have remained fairly stable over the centuries, and land management has traditionally remained in the hands of wealthy landowners. Quarries of various types are probably the only changes to the landscape that have occurred in the last few hundred years. Despite its early history of seismic activity, no major earth movements have occurred in the last millennium. The water which bubbles up from the ground at Bath fell as rain on the nearby Mendip Hills. It percolates down through limestone aquifers to a depth of between 2,700 metres (8,900 ft) and 4,300 metres (14,100 ft) where geothermal energy raises the water temperature to between 64 °C (147.2 °F) and 96 °C (204.8 °F). Under pressure, the heated water rises to the surface along fissures and faults in the limestone. This process is similar to an artificial one known as Enhanced Geothermal System which also makes use of the high pressures and temperatures below the Earth's crust. Hot water at a temperature of 46 °C (114.8 °F) rises here at the rate of 1,170,000 litres (257,364 imp gal) every day, from a geological fault (the Pennyquick fault).

External links

• The Aggregate Landscape of Somerset: Predicting the Archaeological Resource