Clapper Bridge
Tarr Steps, Exmoor, Somerset, England
Ancestor:	Step-stone bridge
Related:	Log bridge
Descendant:	Arch bridge, trestle
Carries:	Pedestrians
Span range:	Short
Material:	Stone
Movable:	No
Design effort:	Low
Falsework required:	No

A clapper bridge is an ancient form of bridge found on the moors of Devon (Dartmoor and Exmoor) and in other upland areas of the United Kingdom including Snowdonia and Anglesey. A step-stone Bridge is a simple means for a Pedestrian to cross a Watercourse during periods of low flow while keeping feet and (particularly Footwear A A pedestrian is a person travelling on foot whether Walking or Running. In Geology, rock is a naturally occurring aggregate of Minerals and/or Mineraloids The Earth's outer solid layer the ‘ Lithosphere Falsework consists of temporary structures used in Construction to support spanning or arched structures in order to hold the component in place until its construction is sufficiently A bridge is a Structure built to span a Gorge, Valley, Road, railroad track, River, Body of water Devon is a large county in the South West of England. The county is also referred to as Devonshire, but that is an entirely unofficial name Dartmoor is an area of Moorland in the centre of Devon, England. Exmoor is a National Park situated on the Bristol Channel coast of south west England The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom, the UK or Britain,is a Sovereign state located Snowdonia (Eryri is a region of North Wales and a National park of in area History There are numerous Megalithic monuments and Menhirs present on Anglesey testifying to the presence of mankind in prehistory It is formed by large flat slabs of granite or schist supported on stone piers (across rivers), or resting on the banks of streams. Granite (ˈɡrænɪt is a common and widely occurring type of intrusive, Felsic, igneous rock. The schists form a group of medium-grade Metamorphic rocks chiefly notable for the preponderance of lamellar Minerals such as Micas chlorite According to the Dartmoor National Park, the word 'clapper' derives from an Anglo-Saxon word, 'cleaca', meaning 'bridging the stepping stones'. The national parks of England and Wales are areas of relatively undeveloped and scenic landscape that are designated under the National Parks and Access to the Countryside Act 1949

Although often believed to be of prehistoric origin, most were erected in medieval times, and some in later centuries. They are often situated close to a ford where carts could cross.

The largest clapper bridge, Anping bridge[1], was built at around 1000 AD in Fujian Province, China. The bridge is 2223 meters long, and the largest granite slab span is 2. 5 feet deep and wide and 35 feet long estimated to weigh 20 tons[2].

Clapper bridge at Wycoller, Pendle, East Lancashire

Another fine example is to be found at Postbridge, on Dartmoor. Postbridge is a hamlet in the heart of Dartmoor in the English county of Devon. Its slabs are over four metres (13ft) long, two metres (6ft 6in) wide and weigh over eight tons each, making the bridge passable to a small cart. It was first recorded in 1380 and was built to facilitate the transportation of tin by pack horses to the stannary town of Tavistock. The Dartmoor tin mining industry is thought to have originated in pre- Roman times and continued right through to the 20th century The word stannary is historically applied to A Tin mine, especially in Devon or Cornwall A region containing tin works Tavistock is a Market town within West Devon, England on the River Tavy, from which its name derives and has a

Surviving examples include the Tarr Steps over the River Barle in Exmoor. The Tarr Steps are a Prehistoric Clapper bridge across the River Barle in the Exmoor National Park, Somerset, England The River Barle runs from northern Exmoor, in Somerset, England to join the River Exe at Exebridge, Devon.

Other larger clapper bridges, such as at Dartmeet and Bellever, have collapsed - their slabs swept away by floods, or raided for building or wall construction. Dartmeet is a popular tourist spot in the centre of Dartmoor, Devon, England. However, there are many other smaller examples in existence on Dartmoor and still in use, such as those at Teignhead Farm (close to Grey Wethers stone circles), Scorhill and across the Wallabrook stream. Grey Wethers consists of a pair of Prehistoric Stone circles situated on grassy Plateau to the north of Postbridge, Dartmoor, in the