Craigleith Quarry Local Geodiversity Site

Craigleith Quarry was the largest and best known of Edinburgh's sandstone quarries, with a worldwide reputation for producing building stone of the highest quality. Although mostly infilled, and now the site of a retail park, enough of the quarry face is visible to illustrate the geology of the quarry, and it was designated a RIGS in 1999 (now renamed a "Local Geodiversity Site (LGS)". We have produced a free leaflet on the Craigleith Quarry LGS (see the Lothian GeoConservation publications page for details).

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Geological Trail


 

1: Craigleith Sandstone The rough sandy feel of this pale brown to grey rock and the individual grains of sand visible reveal the true nature of this sandstone.
Under the microscope, almost all the sand grains are of the colourless mineral quartz. The quartz grains, about 0.25mm in size, are white in photo: the blue is a dye added to show spaces. Quartz is a strong and unreactive mineral, so the sandstone is very hard and durable, ideal properties for a building stone.

The sandstone is made up of thick layers (beds) and contains natural vertical fractures (joints). The quarry men used these features to remove large blocks of building stone with simple tools.

Geological Trail Information

The trail is the cliff, the remains of the quarry face, situated immediately behind Sainsbury’s Superstore.

Caution: Visitors should take care for their own safety, whether from the cliff, from any fallen material, or from the operations within the Retail Park.

NOTE: particularly that the trail does not extend to the part of the cliff past the bushes, which is the loading bay of the adjacent unit.

The trail commences with the oldest rocks and takes you through time to the youngest, highlighting the main rock types and structures present, and how they reveal a tale of changing environments 330 million years ago.

First Impressions

  • The quarry face shows layers (beds) of sedimentary rock dipping down to the right (south).
  • The variation in colour and thickness of the beds suggests different rock types. The rock type is dependent on the environment at the time the sediment was deposited.
  • The oldest beds are located to the left, the overlying beds become progressively younger to the right.
  • The original soft sediments were laid down horizontally, but the hardened rocks were later tilted by dynamic Earth forces.

2: Fossil trees and sun-cracks Vertical cylindrical channels in the rock are Drill Marks cut to aid stone extraction. Within the sandstone beds traces of trees may be seen. Some fossil tree trunks excavated from Craigleith Quarry can still be found, as this one in the Royal Botanic Gardens, Edinburgh.

On the underside of an overhanging ledge of sandstone a network of thin ribs represent sun-cracks. These cracks formed as a result of the drying out of muddy puddles on lake shores, just as they do today. The cracks were later infilled by sand giving this polygonal network. The underlying mud hardened into mudstone, a dark grey crumbly rock.

3: River channels and cross-bedding The sandstone has small beds at a steeper angle to the main bedding. This is cross-bedding, formed as sand ripples moved across the bed of a river channel. This structure shows the direction the sediment was moving, here flowing towards the north.

4: Fossil burrows and plant material The fine-grained mudstones and siltstones here are noticeably thinly bedded and much darker in colour, due to the presence of organic matter such as plant fragments. Black coaly traces of fossil plants can be seen in the face and on fallen blocks. Other fossils here are freshwater mussel shells, Naiadites, and feeding burrows, known as Chondrites, produced by worms living in the soft silty sediment. These suggest an environment of calmer water perhaps in a lake.

 

5: Shelly marine limestone Here the hard, crusty brown weathered limestone contains many marine shells visible in cross-section and in the round. The smooth-shelled, 1cm-across Schizodus is most common. These deposits are evidence of flooding by the sea.

 

6: Soft sedimentary deformation features Within the pale sandstone beds pillow-like structures are seen. Most are several tens of cms to a metre in size, and are associated with dramatic folds and distortion. The underlying and overlying beds are not folded, so deformation likely occurred when the sediments were still soft and wet, possibly triggered by an earthquake. Shaking the wet sediment also forced water upwards creating small sand volcanoes.

7: Oil-Shale Overlying the limestone (at 5) is a thick bed of black tough and papery mudstone. A brown streak when these mudstones are scratched with a knife indicates an unusually high organic content. Microscopic algae were abundant in the original muds resulting in algal rich mudstones known as oil-shales. Oil products extracted from the shales formed the basis of the West Lothian oil industry which flourished during the late 19th and early 20th centuries.

Changing environments Throughout the sedimentary sequence the variety of rock types and structures provide evidence for changing environments during the Carboniferous period. The area around Craigleith changed from one of large river systems and deltas with tropical swamps, to lakes and a shallow sea. Each of these has left its own geological signature in the rock record. It is important that Local Geodiversity Sites like Craigleith are looked after and preserved for others to enjoy and learn from.

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History of Craigleith Quarry

Craigleith Quarry was the largest and best known of Edinburgh's quarries, with a world-wide reputation for producing building stone of the highest quality. It provided most of the building stone for Edinburgh's New Town, and exported stone to London, Europe and the United States. The quarry was active for over 300 years and the final massive hole had faces 110 metres (360 feet) high. Filled with inert waste in the 60 years after quarrying ceased, it has now become the Craigleith Retail Park opened in 1993.

The Early Years The first recorded use of Craigleith stone (then known as Innerleith or Enderleith) was between 1615 and 1619, when 200 arch stones were carried to Edinburgh Castle, using the King's own carts. The quarry also provided stone for Holyrood Palace.

Building the City The construction of the Edinburgh New Town in the 18th and 19th centuries saw a massive increase in demand for building stone. Craigleith stone was used for prestigious buildings such as Register House and Charlotte Square. In 1791 huge, 22 feet-long blocks were used for the 6 pillars at the entrance to Robert Adam's University of Edinburgh Old College. Each pillar weighed nine tons and required 16 horses to haul it. In 1823 a massive block weighing 1500 tons, was transported in pieces to Calton Hill to form the architrave of the National Monument.

Improvements to the Quarry In 1835 an improved shorter route into the City was constructed enabling 60 “horse and cart” to complete five deliveries per day. A railway line was also constructed to carry waste out of the quarry a job which previously had been done by horse.

Dealing with Nature Flooding was a continual problem during the lifetime of the quarry and water was removed by the use of a “Horse Gin” water pump powered by a horse which was eventually superseded by a steam powered pump.
Doctors long showed concern over the health hazards of working the silica-rich sandstone. In 1852, one noted that "a Craigleith man was done at 30 and dead at 35". On his recommendation, the quarriers grew beards and moustaches to act as respirators.

RL Stevenson In Robert Louis Stevenson: The Collected Shorter Fiction edited by Peter Stoneley, Robinson Publishing, 1991, is a description of the misadventures of John Nicholson “Christmas Day and frozen...hiding place in Craig Leith Quarry” 

Leith Docks - The Last of the Stone The last major project for which Craigleith stone was used was for Leith Docks in 1895. Then, more than 90 men were employed; the work force was down to 40 by 1900 and to 25in 1905, when the last good quality building stone was produced.

A New Lease of Life During the First World War the deserted quarry was thought suitably remote site on which to manufacture TNT, previously manufactured at the Lothian Chemical Company.

Last Days of Craigleith Quarry Quarrying recommenced in 1922, with 12 men employed, but by 1942 all work had stopped. After the Second World War, Craigleith Quarry was gradually filled in. However, in 1995 100 tonnes of loose blocks were removed to make the Chinese Garden pathways in the Royal Botanic Garden, Edinburgh.

Building stone today Although sitting in Edinburgh’s most famous sandstone quarry, Sainsbury’s had to go to Stainton in Northumberland for stone for the entrance to the Store. Stainton stone was also used for the Stone Alphabet façade, a major feature at the carpark entrance. Scottish sandstone is still available from a few quarries, such as Clashach in Moray and Cullaloe in Fife, an excellent match for Craigleith stone.

GeoConservation home | Geological Trail | History of Craigleith Quarry | Geological Background | How to find the Quarry | Top of page

Geological Background
The main rock extracted from Craigleith Quarry was sandstone, but there are also exposures of siltstone, mudstone, oil-shale and shelly limestone. These rocks were laid down as horizontally layered soft sediments during the Carboniferous period over 330 million years ago. At this time, Scotland was just south of the equator and enjoyed a seasonally wet, tropical climate. You can find out more about the geology of the local area from Edinburgh Geological Society publications. Lothian Geology and Building Stones of Edinburgh are particularly relevant.

The Craigleith Trees Between 1835 and 1865, several fossils of giant tree (Pitys withamii) were discovered within the quarried sandstone. The largest, know as the Craigleith Tree, is now on display in the Royal Botanical Gardens, Edinburgh. To commemorate the discovery of the fossils, on the wall by the doorway to Sainsbury’s, Carboniferous tree stems and leaves have been carved. Along the pavement, are planted a row of the primitive tree, Dawn Redwood (Metasequoia glyptostroboides) once thought extinct and only known from fossils but found growing in China in 1941.

Earth Movements and Earthquakes The sediments were subsequently buried under 2000m of further sediments, and became hardened to rocks. They were later squeezed and folded by dynamic Earth forces so are now gently inclined to the east.

Craigleith Today Of the once vast exposures of rock at Craigleith Quarry, only one or two preserved areas remain. But their fascinating features provide clues to the geological and historical past of Craigleith. Thanks to Sainsbury's sympathetic development of the site, Lothian and Borders GeoConservation designated the face behind the store as a Regionally Important Site in 1999.

GeoConservation home | Geological Trail | History of Craigleith Quarry | Geological Background | How to find the Quarry | Top of page

How to find Craigleith Quarry

Craigleith Quarry lies approximately 3km west of Edinburgh city centre along the Queensferry Road at its intersection with Craigleith Road and South Groathill Avenue (Multimap link). The quarry has now been infilled and built on, starting in 1993 when Sainsbury’s opened their superstore. It has since developed into the Craigleith Retail Park. Some of the upper part of the quarry face remains and reveals evidence of Edinburgh’s geological and historical past.

By bus:  Craigleith can reached by Lothian Buses from Edinburgh. Currently (2005) routes 24 and 38 go into the retail park and routes 41 and 42 stop nearby, though this may change. Ask for Craigleith Retail Park.

By car: The main entrance into Craigleith Retail Park is off Craigleith Road as you approach traffic lights on the (A90) Queensferry Road. There is ample parking in the Retail Park car park.

The geological trail is located behind Sainsbury’s superstore. Visitors should report to the information desk inside the store before and after visiting the trail for safety and security purposes. The trail can be accessed by a footpath which starts at the South end of the store.

Leaflet produced by Lothian and Borders RIGS ©2005
Text by: Sarah Arkley, Mike Browne, Ewan Hyslop and LaBRIGS members.
Designed by: Derek Munn
Cover oil painting Edinburgh from Craigleith Quarry by John Bell and black & white photograph Craigleith Quarry by Thomas Begbie c1850, both courtesy of The City Art Centre. Edinburgh.
Coloured lithograph Craigleith Quarry with Edinburgh beyond c1854 by William Leighton Leitch courtesy of Edinburgh City Library.
Quarry drawing, courtesy of Royal Society of Edinburgh.
Other photographs from Alan Ross, Lothian & Borders RIGS Group, and British Geological Survey collection.
Funding by Scottish Natural Heritage and Alan Ross, editor of History of Craigleith www.craigleithhill.co.uk.

 


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