Bath Stone is an
oolitic limestone
Limestone is a type of carbonate rock, carbonate sedimentary rock which is the main source of the material Lime (material), lime. It is composed mostly of the minerals calcite and aragonite, which are different Polymorphism (materials science) ...
comprising granular fragments of
calcium carbonate
Calcium carbonate is a chemical compound with the chemical formula . It is a common substance found in Rock (geology), rocks as the minerals calcite and aragonite, most notably in chalk and limestone, eggshells, gastropod shells, shellfish skel ...
originally obtained from the
Middle Jurassic
The Middle Jurassic is the second Epoch (geology), epoch of the Jurassic Period (geology), Period. It lasted from about 174.1 to 161.5 million years ago. Fossils of land-dwelling animals, such as dinosaurs, from the Middle Jurassic are relativel ...
aged
Great Oolite Group of the
Combe Down and Bathampton Down Mines under
Combe Down,
Somerset
Somerset ( , ), Archaism, archaically Somersetshire ( , , ) is a Ceremonial counties of England, ceremonial county in South West England. It is bordered by the Bristol Channel, Gloucestershire, and Bristol to the north, Wiltshire to the east ...
, England. Its honey colouring gives the
World Heritage City of
Bath, England, its distinctive appearance. An important feature of Bath Stone is that it is a '
freestone', so-called because it can be sawn or 'squared up' in any direction, unlike other rocks such as
slate
Slate is a fine-grained, foliated, homogeneous, metamorphic rock derived from an original shale-type sedimentary rock composed of clay or volcanic ash through low-grade, regional metamorphism. It is the finest-grained foliated metamorphic ro ...
, which form distinct layers.
Bath Stone has been used extensively as a building material throughout southern England, for churches, houses, and public buildings such as railway stations.
Some quarries are still in use, but the majority have been converted to other purposes or are being filled in.
Geological formation
Bath Stone is an
oolitic limestone
Limestone is a type of carbonate rock, carbonate sedimentary rock which is the main source of the material Lime (material), lime. It is composed mostly of the minerals calcite and aragonite, which are different Polymorphism (materials science) ...
comprising granular fragments of
calcium carbonate
Calcium carbonate is a chemical compound with the chemical formula . It is a common substance found in Rock (geology), rocks as the minerals calcite and aragonite, most notably in chalk and limestone, eggshells, gastropod shells, shellfish skel ...
laid down during the
Jurassic Period (195 to 135 million years ago) when the region that is now Bath was under a shallow sea. Layers of
marine sediment
Marine sediment, or ocean sediment, or seafloor sediment, are deposits of insoluble particles that have accumulated on the seafloor. These particles either have their origins in soil and Rock (geology), rocks and have been Sediment transport, ...
were deposited, and individual spherical grains were coated with
lime as they rolled around the sea bed, forming the
Bathonian Series of rocks. Under the microscope, these grains or
ooliths (''egg stones'') are
sedimentary rock
Sedimentary rocks are types of rock (geology), rock formed by the cementation (geology), cementation of sediments—i.e. particles made of minerals (geological detritus) or organic matter (biological detritus)—that have been accumulated or de ...
formed from
ooids: spherical grains composed of concentric layers. That name derives from the
Hellenic word ''òoion'' for
egg. Strictly, oolites consist of ooids of diameter 0.25–2 mm.
Rocks composed of ooids larger than 2 mm are called
pisolites. They frequently contain minute fragments of shell or rock, and sometimes even decayed skeletons of marine life. Bath Stone was taken from the Bath Oolite Member and the Combe Down Member of the Chalfield Oolite Formation, part of the
Great Oolite Group.
Use as a building stone

An important feature of Bath Stone is that it is a
freestone, one that can be sawn or 'squared up' in any direction, unlike other rocks such as
slate
Slate is a fine-grained, foliated, homogeneous, metamorphic rock derived from an original shale-type sedimentary rock composed of clay or volcanic ash through low-grade, regional metamorphism. It is the finest-grained foliated metamorphic ro ...
, which have distinct layers. In the Roman and medieval periods, Bath Stone was extensively used on domestic and ecclesiastical buildings, as well as civil engineering projects such as bridges.
The
Royal National Hospital for Rheumatic Diseases, which was founded in 1738, was designed by
John Wood the Elder and built with Bath Stone. There is a fine
pediment
Pediments are a form of gable in classical architecture, usually of a triangular shape. Pediments are placed above the horizontal structure of the cornice (an elaborated lintel), or entablature if supported by columns.Summerson, 130 In an ...
on the building, again in Bath Stone, which depicts the parable of the
good Samaritan.
St Stephen’s Church on Lansdown Hill, Bath, was constructed from a limestone sourced from the
Limpley Stoke mine, south of the city.

The material has also been used widely outside Bath itself.
Claverton Pumping Station at
Claverton, which was built of Bath Stone in about 1810, pumps water from the
River Avon to the
Kennet and Avon Canal, using power from the flow of the River Avon. The stone was also used for the
Dundas Aqueduct, which is long, and has three arches built of Bath Stone, with
Doric pilasters, and balustrades at each end.
Much of
Bristol Cathedral
Bristol Cathedral, formally the Cathedral Church of the Holy and Undivided Trinity, is a Church of England cathedral in the city of Bristol, England. It is the seat of the Bishop of Bristol. The cathedral was originally an abbey dedicated to St ...
was built of Bath Stone, and the Wills Tower, which is the dominant feature of the
Wills Memorial Building, is constructed in
reinforced concrete
Reinforced concrete, also called ferroconcrete or ferro-concrete, is a composite material in which concrete's relatively low tensile strength and ductility are compensated for by the inclusion of reinforcement having higher tensile strength or ...
faced with Bath and Clipsham stone. Bristol's
Cabot Tower was also faced with Bath Stone.
Arno's Court Triumphal Arch was built from Bath Stone in about 1760, and was later dismantled before being rebuilt in its current location.
Bath Stone was also favoured by architect
Hans Price, who designed much of 19th-century
Weston-super-Mare
Weston-super-Mare ( ) is a seaside town and civil parish in the North Somerset unitary district, in the county of Somerset, England. It lies by the Bristol Channel south-west of Bristol between Worlebury Hill and Bleadon Hill. Its population ...
. In
Barnstaple
Barnstaple ( or ) is a river-port town and civil parish in the North Devon district of Devon, England. The town lies at the River Taw's lowest crossing point before the Bristol Channel. From the 14th century, it was licensed to export wool from ...
, the 1855 construction of Butchers Row used Bath Stone.
In London, the neo-classical
Georgian mansion
Lancaster House was built from Bath Stone in 1825 for the
Duke of York and Albany, the second son of
King George III, as were
St Luke's Church, Chelsea, in 1824, and several other churches including
Church of Christ the King, Bloomsbury.
Apsley House, the town house of the Dukes of Wellington, was remodelled by the 1st Duke in Bath Stone cladding over the original red brick.
In
Reading, the original building of the
Royal Berkshire Hospital of 1839, together with the wings added in the 1860s, are built of Bath Stone, with slate roofs.
They are now
listed grade II* by
English Heritage
English Heritage (officially the English Heritage Trust) is a charity that manages over 400 historic monuments, buildings and places. These include prehistoric sites, a battlefield, medieval castles, Roman forts, historic industrial sites, Lis ...
. In 1860, the nearby
Reading railway station, incorporating a tower and clock, was constructed by the Great Western Railway using Bath Stone, and the company also used it for
Chippenham station.

Other mansions which have used Bath Stone include
Gatcombe Park,
Goldney Hall,
Tyntesfield,
South Hill Park, and
Spetchley Park.
In 2002 the East End of
Truro Cathedral was completely renovated and restored with some of the ornate Bath Stone replaced with harder-wearing Syreford stone. In 2005 the west front was restored similarly.
Mines
Bath stone was mined underground at
Combe Down and Bathampton Down Mines, in Somerset; and as a result of cutting the
Box Tunnel, at various locations in
Wiltshire
Wiltshire (; abbreviated to Wilts) is a ceremonial county in South West England. It borders Gloucestershire to the north, Oxfordshire to the north-east, Berkshire to the east, Hampshire to the south-east, Dorset to the south, and Somerset to ...
, including
Box
A box (plural: boxes) is a container with rigid sides used for the storage or transportation of its contents. Most boxes have flat, parallel, rectangular sides (typically rectangular prisms). Boxes can be very small (like a matchbox) or v ...
and
Corsham
Corsham is a historic market town and civil parishes in England, civil parish in west Wiltshire, England. It is at the southwestern edge of the Cotswolds, just off the A4 road (England), A4 national route. It is southwest of Swindon, east of ...
.
In the early 18th century,
Ralph Allen promoted the use of the stone in Bath itself, and demonstrated its potential by using it for his own mansion at
Prior Park. Following a failed bid to supply stone to buildings in London, Allen wanted a building which would show off the properties of Bath Stone as a building material.
He acquired the stone quarries at Combe Down and Bathampton Down Mines.
Hitherto, the quarry masons had always hewn stone roughly providing blocks of varying size. Wood required stone blocks to be cut with crisp, clean edges for his distinctive classical façades. The distinctive honey-coloured Bath Stone was used to build the Georgian city. Stone was extracted by the "room and pillar" method, by which chambers were mined, leaving pillars of stone to support the roof.
Allen built a railway line from his mine on
Combe Down which carried the stone down the hill, now known as Ralph Allen Drive, which runs beside Prior Park, to a wharf he constructed at
Bath Locks on the
Kennet and Avon Canal to transport stone to London.
[Durman pp91-94]
In the 18th century mines at Budbury near
Bradford on Avon and
Corsham
Corsham is a historic market town and civil parishes in England, civil parish in west Wiltshire, England. It is at the southwestern edge of the Cotswolds, just off the A4 road (England), A4 national route. It is southwest of Swindon, east of ...
the mines were developed by the Methuen and Northey families. The mine at
Monkton Farleigh was leased to quarrymen by the
Diocese of Salisbury
The Diocese of Salisbury is a Church of England diocese in the south of England, within the ecclesiastical Province of Canterbury. The diocese covers the historic county of Dorset (which excludes the deaneries of Bournemouth and Christchurch, ...
.
Underground extraction of Bath Stone continues in the Corsham area but on a smaller scale than previously. For example, Hanson Bath & Portland Stone, part of the
HeidelbergCement Group, operates
Hartham Park Underground Quarry in the Hudswell district (southwest of Pickwick). The Bath Stone Group operates the Stoke Hill mine.
Box Mine
The
Box Mine consists of a network of tunnels, which originate from stone mining work. Stone extraction started during the
Roman occupation of Britain
Roman Britain was the territory that became the Roman province of ''Britannia'' after the Roman conquest of Britain, consisting of a large part of the island of Great Britain. The occupation lasted from AD 43 to AD 410.
Julius Caesa ...
and ceased in 1968. The mine is now popular for recreational underground trips, and is home to a large population of
bats. Up to 10% of the total British population of
greater horseshoe bat
The greater horseshoe bat (''Rhinolophus ferrumequinum'') is an Insectivore, insectivorous bat of the genus ''Rhinolophus''. Its distribution covers Europe, Northern Africa, Central Asia and Eastern Asia. It is the largest of the horseshoe bats i ...
uses the mine at times, and a maximum of 230 individuals of the species have been counted at the site. The
Lesser Horseshoe Bat also uses the mine, as do the four
Myotis species:
Whiskered,
Brandt's,
Natterer's and
Daubenton's bats.
Combe Down and Bathampton Down Mines
Combe Down and Bathampton Down Mines date from the 17th and 18th century when stone was extracted by the "room and pillar" method, by which chambers were mined, leaving pillars of stone between them to support the roof.
The mine contains a range of mine features including well preserved
tramways, cart-roads and crane bases. The walls and pillars of the mine are studded with
pick and tool marks, and show evidence of the use of huge stone saws, all of which bear testimony to the variety of techniques used to extract the stone over the mine's three hundred-year history.
No mine abandonment plans of either the tunnels or the caverns, known as voids, were made prior to the 1872 Mining Act.
Following their closure, the mines were used for a variety of purposes, including a
mushroom
A mushroom or toadstool is the fleshy, spore-bearing Sporocarp (fungi), fruiting body of a fungus, typically produced above ground on soil or another food source. ''Toadstool'' generally refers to a poisonous mushroom.
The standard for the n ...
farm, and as an
air-raid shelter during the
World War II
World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...
Baedeker raids on Bath.
Other uses of stone mines
During the 1930s there was a recognition of a need to provide secure storage for munitions in the south of the United Kingdom, and a large area of the quarries around the Corsham area was renovated by the
Royal Engineers
The Corps of Royal Engineers, usually called the Royal Engineers (RE), and commonly known as the ''Sappers'', is the engineering arm of the British Army. It provides military engineering and other technical support to the British Armed Forces ...
as one of three major munitions stockpiles. This ammunition depot was serviced by a spur railway line from the main London to Bristol line, branching off just outside the eastern entrance to
Box Tunnel. A portion of the underground quarry complex was developed as a '
shadow factory' for aircraft engines, to act as a fallback should the
Bristol Engine company Factory at
Filton be taken out of action by hostile bombing. In practice this factory was never used.
In another part of the quarry area, Royal Air Force Box was established as the Headquarters of
No10 Fighter Group,
Royal Air Force
The Royal Air Force (RAF) is the Air force, air and space force of the United Kingdom, British Overseas Territories and Crown Dependencies. It was formed towards the end of the World War I, First World War on 1 April 1918, on the merger of t ...
. RAF Box was later renamed
RAF Rudloe Manor and expanded to encompass a number of communications functions, including No1 Signal Unit, Controller Defence Communications Network, No1001 Signal Unit Detachment and Headquarters RAF Provost & Security Service. No1SU and CDCN were both housed in bunkers within the quarry complex, which also included an RAF Regional Command Centre for the South West of England.
British defence doctrine during the early
Cold War
The Cold War was a period of global Geopolitics, geopolitical rivalry between the United States (US) and the Soviet Union (USSR) and their respective allies, the capitalist Western Bloc and communist Eastern Bloc, which lasted from 1947 unt ...
period indicated a requirement for a
fallback location for central government outside London, to assume national control in the event of London being destroyed. The quarry complex at Corsham was chosen for this location and development of the site commenced in the 1950s. In the event of an imminent
nuclear attack, it was assumed that the government would be evacuated from London by rail or
helicopter
A helicopter is a type of rotorcraft in which Lift (force), lift and thrust are supplied by horizontally spinning Helicopter rotor, rotors. This allows the helicopter to VTOL, take off and land vertically, to hover (helicopter), hover, and ...
. The facility would provide a safe haven for the
Prime Minister
A prime minister or chief of cabinet is the head of the cabinet and the leader of the ministers in the executive branch of government, often in a parliamentary or semi-presidential system. A prime minister is not the head of state, but r ...
, the
Cabinet, commanders of the
Royal Air Force
The Royal Air Force (RAF) is the Air force, air and space force of the United Kingdom, British Overseas Territories and Crown Dependencies. It was formed towards the end of the World War I, First World War on 1 April 1918, on the merger of t ...
,
Royal Navy
The Royal Navy (RN) is the naval warfare force of the United Kingdom. It is a component of His Majesty's Naval Service, and its officers hold their commissions from the King of the United Kingdom, King. Although warships were used by Kingdom ...
, and
British Army
The British Army is the principal Army, land warfare force of the United Kingdom. the British Army comprises 73,847 regular full-time personnel, 4,127 Brigade of Gurkhas, Gurkhas, 25,742 Army Reserve (United Kingdom), volunteer reserve perso ...
and supporting
civil servant
The civil service is a collective term for a sector of government composed mainly of career civil service personnel hired rather than elected, whose institutional tenure typically survives transitions of political leadership. A civil service offic ...
s and military personnel. Facilities inside the complex included accommodation and catering for nearly 4,000 people, including a
hospital
A hospital is a healthcare institution providing patient treatment with specialized Medical Science, health science and auxiliary healthcare staff and medical equipment. The best-known type of hospital is the general hospital, which typically ...
, organic electrical generation and the ability to seal the complex from the outside environment, contaminated by
radiation
In physics, radiation is the emission or transmission of energy in the form of waves or particles through space or a material medium. This includes:
* ''electromagnetic radiation'' consisting of photons, such as radio waves, microwaves, infr ...
or other threat.
The defence facilities known by various code names like Stockwell, Turnstile, Hawthorn and Burlington have been built in quarries include Military Command & Control, storage and a fallback seat of national government. Some areas of the quarry complex were hardened and provided with support measures to ensure resilience in the event of a
nuclear attack. The site was decommissioned and placed in a state of care & maintenance in the mid 1990s following the fragmentation of the
Soviet Union
The Union of Soviet Socialist Republics. (USSR), commonly known as the Soviet Union, was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 until Dissolution of the Soviet ...
and the end of the cold war. The site has been offered for sale, conditional on a
Private Finance Initiative for the continued use of above ground facilities.
Corsham Computer Centre was built into Hudswell Quarry during the 1980s and current examples of other uses include not only defence establishments, but also a
wine cellar
A wine cellar is a storage room for wine in bottles or barrels, or more rarely in carboys, amphorae, or plastic containers. In an ''active'' wine cellar, important factors such as temperature and humidity are maintained by a climate control s ...
at Eastlays (near
Gastard) and storage for
magnetic media (for
Off-site Data Protection) at Monk's Park (near Neston).
The mine at Monkton Farleigh was used as a Central Ammunition Depot during World War II. Part of the site which was not used by the military is now a part of the
Brown's Folly 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 ...
.
Mine rehabilitation
During 1989 a utilities contractor unexpectedly broke through into part of the mines complex at Combe Down whilst excavating a trench. This raised concerns locally, resulting in the then Bath City Council commissioning studies to survey the condition of the mines. It was clear that the mines were in a very dangerous state and some experts considered them to be the largest, shallowest, and most unstable of their kind in Europe. Approximately 80% of the mines, which are up to high and cover a total area of about , had less than cover and as little as in some places.
In March 1999, the then
Department of Environment, Transport and Regions (DETR), now known as the
Department for Communities and Local Government, announced a Land Stabilisation Programme, based on the Derelict Land Act 1982. A Parliamentary
Statutory Instrument (2002 No. 2053) was needed before the work could be undertaken.
Foam concrete was selected as the best material to use in the large-scale infilling of the old mine workings. Over of foamed concrete were placed in the shallower underground mines, making it the single largest application of foamed concrete in the United Kingdom.
See also
*
References
External links
*
{{Architecture of England
Building stone
*Bath Stone
Culture in Bath, Somerset
Economy of Bath, Somerset
Geologic formations of the United Kingdom
Geology of Somerset
Geology of Wiltshire
History of Bath, Somerset
Limestone
Mining in Somerset