Clints Quarry is a Carboniferous limestone nature reserve near Egremont, where corals and crinoid fragments can be seen in weathered rock. Its fossil-rich beds and ancient solution hollows record changing conditions on a shallow tropical shelf. Visit to observe and photograph the geology, leaving fossils and the protected quarry undisturbed.
FIND FREQUENCY: ♦♦ – Corals and crinoid debris can be recognised in exposed limestone and existing loose rock. This is an observation and photography visit; leave specimens in place.
CHILDREN: ♦♦ – The walk is short, but sudden drops, steep ground and deep water demand close supervision. Keep children on the reserve paths and well away from edges.
ACCESS: ♦♦♦♦ – A signed circular route of about 0.9 km includes steps and uneven ground. Stay on the paths to protect the reserve’s plants and animals.
TYPE: – Disused limestone quarry and nature reserve; fossiliferous limestone, old scree and quarry faces.
DIRECTIONS
♦ Clints Quarry is just off the A5086, a short distance north of Egremont. From Egremont, take the first left turn towards Moor Row.
♦ Cumbria Wildlife Trust’s directions identify roadside parking just beyond the junction, with a further parking place about 100 m along the road opposite the reserve entrance. Park considerately and keep entrances clear.
♦ Use the signed reserve entrance and follow the paths through the woodland into the quarry. The route includes steps; the circular walk is approximately 0.9 km.
♦ View the quarry and its rock exposures from the established paths. Do not leave the route to reach scree, quarry edges or the water.
♦ Reserve reference: NY 008 124. Existing UK Fossils location: 54.49735°N, 3.53262°W.
FOSSIL HUNTING
The most recognisable fossils at Clints are colonial corals. In weathered limestone, closely packed small circles may be cross-sections through the branching tubes of Siphonodendron junceum, the coral called Lithostrotion junceum in the original guide and photograph labels. A lengthwise section can show the same colony as a bundle of elongated stems. Look at surfaces already exposed beside the path rather than breaking rock to make a fresh section.
Crinoidal limestone contains abundant fragments of sea-lily skeletons. Their stem pieces commonly appear as small discs or short cylinders, while a cut or weathered face may show many pale circular grains together. Brachiopod shells also occur. These fossils formed part of a shallow-sea community; a rock densely packed with broken skeletons records accumulated debris, rather than a collection of complete animals.
The named limestone beds explain some of the variety. Siphonodendron junceum occurs at several levels in the Junceum Limestone. Near the top of the Potholes Limestone, the historically important Orionastraea Band contains colonial corals including Orionastraea edmondsi, Corwenia rugosa and Nemistium edmondsi. These are documented records from the Clints–Steelbarrow quarry complex, rather than a promise that each will be easy to identify from the visitor path.
The White Limestone has yielded the brachiopod Davidsonina septosa, while the Saccammina Limestone and the sediment filling its upper hollows contain the organism now written Saccamminopsis. The old bed names are useful guides to the literature, but a loose block cannot reliably be assigned to a precise bed simply because it contains a familiar fossil. Faulting, quarrying and scree movement have mixed material from different levels.
The most useful approach is to examine accessible, naturally weathered surfaces with a hand lens and take a photograph that includes a scale. Record the part of the quarry and whether the fossil is in an exposure or a loose block. The original visit found fossiliferous scree in several places, but vegetation and rockfall change what can be seen. Do not push through brambles or disturb plants to reach a specimen, and never work beneath a face.
Leave fossils where they lie. Ask Cumbria Wildlife Trust before proposing any sampling or removal; public access to the nature reserve does not itself provide collecting permission.
Significant discoveries, geological research and conservation milestones at Clints Quarry.
1600s – Limestone working is recorded
The reserve history records limestone working from the seventeenth century, supplying stone for construction and agriculture. No exact opening year is established.
1925 – An important algal marker is recorded
Scientific work documented the Girvanella-bearing marker in the Clints succession, contributing to later correlation of the limestone beds.
1929 – A Clints coral enters the taxonomic record
Hudson described Orionastraea edmondsi. Material from the top of the Potholes Limestone at Clints includes the paratype now catalogued as BGS GSM 48803, collected by C. Edmonds. The museum record does not establish an exact discovery date.
1930 – Quarrying ceases
The end of limestone extraction allowed vegetation and wildlife to recolonise the workings, while the old quarry faces continued to expose the geological succession.
1931 – The Survey documents the higher limestone succession
A Geological Survey account described the higher Brigantian rocks of the Clints quarry complex, providing a foundation for later stratigraphic work.
1969 – Initial scientific-site protection
Clints Quarry was first notified as a Site of Special Scientific Interest, recognising the importance of the locality.
1984 – The nature reserve is purchased
Cumbria Wildlife Trust acquired the reserve from British Steel and Lord Egremont, securing it for conservation.
1987 – SSSI notification and boundary revision
The site was notified under the Wildlife and Countryside Act 1981, with a revised boundary. The recorded partial boundary deletion did not remove the site’s SSSI designation.
1994-04-09 – A field excursion examines the ancient limestone surfaces
An excursion led by Thurlow examined the Clints sequence, including the oncolitic base of the Rough Beds and the sediment-filled dissolution hollows. The report was published in 1996.
1996 – Seven White Limestone cycles are analysed
Thurlow published a detailed comparison of the White Limestone, recognising W1–W7 in the Clints column. The work linked changing carbonate textures and soil-covered surfaces to repeated environmental cycles.
2011 – Modern Eskett Limestone terminology is established
The BGS stratigraphical framework included Clints as a reference section for the Fourth Shale and Fourth Limestone within the Eskett Limestone Formation.
GEOLOGY
Clints exposes late Asbian to Brigantian rocks of the Visean, within the Lower Carboniferous. In current British Geological Survey terminology these limestones belong to the Eskett Limestone Formation of the Great Scar Limestone Group. Older accounts use the Chief Limestone Group and a succession of numbered limestones and shales. Those historical divisions remain valuable for following the published quarry descriptions, but the whole Eskett Formation is much more extensive in age and thickness than the beds visible here.
The rocks accumulated on a warm, shallow carbonate shelf beside the north-western edge of the Lake District high. Corals, brachiopods and crinoids lived in the sea, and their skeletons contributed to the limestone. Repeated changes in water depth and sediment supply produced different textures, from fine lime mud to grain-rich limestone. The relatively limestone-dominated local sequence contrasts with the more strongly alternating limestone, shale and sandstone successions found in parts of northern England.
At times the sea withdrew and exposed the carbonate surface to weathering. Soil clays and irregular dissolution surfaces preserve these interruptions. The striking ancient “potholes” are solution hollows in limestone, subsequently filled with sediment; they should not automatically be interpreted as holes drilled by a river. Sandstone and siltstone filling the upper surface of the Potholes Limestone contain a few plant fragments, while the mottled sediment above the Saccammina Limestone is interpreted as marine material filling an uneven seafloor.
The quarry complex does not expose one continuous, undisturbed vertical stack. Normal faults trending roughly north-north-west to south-south-east displace or repeat the beds, and published accounts combine observations from Clints and adjoining Steelbarrow. The familiar quarry-face photograph is only about 17 m high and shows parts of several named limestones. It cannot be used as a scale for the complete published succession or as a safe route to each horizon.
Detailed geology, named limestone beds and White Limestone cycles at Clints Quarry
The account below follows the succession upwards, from the oldest described rocks to the youngest. It combines the published Clints–Steelbarrow quarry description with observations explicitly recorded at Clints. Steelbarrow, centred near NY 006 123, is an adjoining quarry rather than another name for the entire visitor reserve. Faults and separate exposures mean that these beds cannot all be read as one uninterrupted face.
GREAT SCAR LIMESTONE GROUP
Eskett Limestone Formation
The exposed local sequence is late Asbian to Brigantian, within the Visean. Clints is a BGS reference section for the Fourth Shale and Fourth Limestone. The historical Chief Limestone Group and numbered beds used below predate the modern Eskett name. The approximately 85 m thickness and Holkerian–Pendleian age range quoted for the formation as a whole describe the wider west Cumbrian succession, not the complete height or age span of this reserve exposure.
Upper surface of the Fifth Limestone. The lowermost part of the published quarry-complex description includes the top of this limestone, with an irregular weathered surface. A full local thickness is not established for the visitor exposure and is therefore not added to the succession here.
Fourth Shale: the entrance-cutting interval. Beneath the White Limestone, the BGS memoir describes a 5 m section of mainly calcareous mudstone passing upwards into pink and grey micaceous siltstone. Johnson’s account gives less than 2 m at Clints. These are different published descriptions; there is insufficient evidence to treat one as a replacement measurement or to average them. The 1994 excursion described red and green siltstones overlain by silty, nodular limestone, without a separate thickness.
White Limestone: approximately 20 m in the published composite. Thick limestone beds alternate with palaeosol clay seams. Some of these ancient soils probably developed from bentonitic material, meaning altered volcanic ash; a soil surface does not necessarily imply that all its clay originated through weathering of limestone. A thicker clay in the middle changes laterally into alternating clay and limestone, while sandstone occupies hollows in the upper dissolution surface. Exposures near the entrance and the northern face contribute to the Clints description. The brachiopod Davidsonina septosa helps characterise the Asbian part of the sequence.
Thurlow’s study recognises seven White Limestone cycles, W1–W7, in the Clints column. Each records a phase of carbonate sedimentation, commonly ending in emergence and soil formation. The published comparison diagram has no metre scale, so individual cycle thicknesses cannot be read from its drawn heights. Features found only at Kelton, Salterhall or other quarries are not transferred to Clints.
W1: flooding, deepening and shallowing. A thin, fine-grained, porcellanous limestone represents the first lagoonal flooding. Nodular limestone records deeper water, followed by crinoid-rich packstone formed as conditions shallowed. A dissolution surface and soil clay terminate the cycle. Among the platform-interior sections compared in the study, this cycle was recognised only at Clints.
W2: restricted mud followed by a shoal. Fenestral carbonate mudstone at the base contains small void-like structures associated with very shallow conditions. It is followed by grainstone poor in large fossils, interpreted as a shoal or barrier deposit. Dissolution and clay mark the top. The upper lagoonal facies described at Kelton is not documented here.
W3: a thin crinoidal interval. Crinoid-rich packstone accumulated below ordinary wave action. Its upper boundary is an irregular dissolution surface with clay, recording renewed exposure and soil development. No numerical Clints thickness is supplied.
W4: coated grains and open-marine influence. Coated-grain grainstone is recorded in the Clints section. The abundance of coated grains may indicate more open-marine conditions, but the description does not establish a clear shallowing-upwards trend within this cycle.
W5: another shallow-water cycle. A thin interval begins with fenestral mudstone below a flooding surface, followed by grainstone with few large fossils. Minor dissolution and a thin clay cap close the cycle. More specific soil alteration documented at Salterhall is not a Clints observation.
W6: fossil-rich grainstone. The limestone is rich in larger fossil material, with no clear vertical depositional trend reported within the cycle. A slightly irregular dissolution surface and thin clay mark its top. The published Clints column supports this cycle but does not give its individual thickness.
W7: the final White Limestone cycle. Fossil-rich grainstone is capped by minor dissolution and clay. Interbedded porcellanites described in this cycle at Kelton and Salterhall are not established in the Clints column.
The oncolitic marker and the White–Rough boundary. The 1994 Clints field account places the base of the Rough Beds at the first dark oncolitic limestone, with a burrowed base above a thin soil clay. The GCR puts a Girvanella-bearing marker near the base of the Rough Limestone, immediately above the local Asbian–Brigantian boundary. The BGS memoir instead describes a Girvanella-bearing mudstone at the top of the White Limestone, also just above the Brigantian base. These differing lithological conventions should remain distinct; they do not demonstrate two separate marker beds.
Rough Limestone: 14 m in the GCR description. Dark, relatively bituminous limestone overlies the White Limestone interval. The published 14 m value belongs to the Clints–Steelbarrow composite. Alternative district figures of 13 m or 15–20 m are not additional thicknesses or separate units.
Spotted Limestone: 6 m in the GCR description. Darker patches within pale limestone give the rock its spotted or apparently broken-up appearance, termed pseudobrecciation. This named unit is visible in the published Clints face photograph. Broader district descriptions give a range of 6–9 m; that range should not be added to the 6 m local-composite value.
Intervening clastic beds: a regional qualification. Regional accounts describe shale and red-bed sediment in this part of the succession around Clints, with sandstone and evidence of plant roots. They do not establish a separately measured bed in the GCR visitor-quarry log. A convenient 3 m clastic layer must therefore not be inserted into a local measured column.
Potholes Limestone: 6 m in the GCR description. The upper surface has pronounced dissolution relief, with hollows as much as 2 m deep. This is the depth of the irregular surface, not another 2 m bed. Sandstone and siltstone fill the hollows and contain a few plant fragments. The 1994 excursion noted overhanging solution forms and red clay lining the sandstone fill, consistent with weathering and sediment infilling rather than a simple mechanically cut river pothole.
The Orionastraea Band near the top of the Potholes Limestone. Recorded colonial corals include Orionastraea edmondsi, Corwenia rugosa and Nemistium edmondsi; the GCR also discusses Palastraea regia in this assemblage. BGS specimen GSM 48803 is catalogued as a paratype of Orionastraea edmondsi from the top of the Potholes Limestone at Clints. Its museum donation information is not a secure field-discovery date.
Saccammina Limestone: 6 m in the GCR description. Grey, crinoidal limestone contains the organism now written Saccamminopsis. Saccammina is retained as the historical bed name; it does not require the fossil to be assigned to that genus today. The fossil’s modern biological affinity is not resolved by the old limestone name.
The reported Erythrospongia Sponge Band. The GCR places this historically traced horizon near the top of the Saccammina Limestone, following work associated with Hudson and Edmonds. Other accounts are more cautious about its identity and continuity. It is therefore a qualified historical correlation, not a distinctive band that every visitor can confidently locate.
Mottled shale above the Saccammina Limestone. Mottled sediment fills hollows in the potholed upper limestone surface and also contains Saccamminopsis. The GCR interprets it as marine sediment occupying the irregular relief, unlike the terrestrial soil clays at some other levels. No separate local thickness is supplied.
Junceum Limestone and the cherty upper interval. The GCR gives approximately 16 m for the Junceum Limestone in the quarry complex, with Siphonodendron junceum at several levels, chert nodules and silicified fossils. BGS subdivides an overlying Cherty Limestone and gives about 20 m for the combined district interval. These conventions do not justify adding 20 m above the 16 m GCR unit or inventing a separately measured Cherty bed at the visitor exposure.
Third Shale: not a confirmed measured visitor exposure. This name belongs to the wider historic succession above the Junceum and Cherty limestones. The inspected GCR account does not provide an exact measured Clints visitor exposure. Its regional presence is relevant to correlation, but no thickness or continuous exposed layer is assigned here.
Third Limestone: 2 m in the south-west corner. The local GCR description records grey crinoidal limestone with corals and brachiopods in the south-west corner of Clints. This is a specific exposure within the quarry, distinct from the better-known northern face.
Base of the Orebank Sandstone. Pale, quartz-rich sandstone is exposed in the same south-western part of the quarry. Only its base is established in this visitor-section account. The historical 18 m value for the wider Clints-area package, and approximately 20 m regional values, do not show that the full thickness is visible here.
Faults and scale. North-north-west to south-south-east normal faults displace the sequence. The approximately 17 m north-west face illustrated in the GCR displays parts of the Spotted, Potholes, Saccammina and Junceum limestones. Its visible height is not the full composite succession and cannot be used to recalculate the individual published thicknesses.
References.
Cossey and colleagues (2004), British Lower Carboniferous Stratigraphy, GCR 29, Clints Quarry, pp. 196–198.
Akhurst and colleagues (1997), Geology of the west Cumbria district.
Thurlow (1996), White Limestone cycles, pp. 5–34, and report of the 9 April 1994 excursion, pp. 63–67.
Johnson (1992), Dinantian carbonate cycles of west Cumbria.
BGS Eskett Limestone Formation definition, following Dean and colleagues (2011).
BGS type-fossil catalogue: Orionastraea edmondsi, GSM 48803.
SAFETY
Cumbria Wildlife Trust warns of steps, steep exposed ground, sudden drops of up to 20 m and open water. Stay on established reserve paths and keep well back from quarry edges, faces, loose rock and pools. The deep water near the entrance is a particular reason to supervise children closely.
Mud, wet limestone, leaves and uneven steps can be slippery. Wear footwear with a firm grip, avoid the reserve’s exposed parts in poor conditions and turn back if a path is unsafe. Do not climb scree or approach a face to photograph fossils. Mobile reception may be limited, so let someone know your plans and do not rely solely on a phone for navigation.
Follow temporary signs and any route closures. Keep dogs on leads, especially around the reserve’s grazing animals, and avoid disturbing vegetation or wildlife.
EQUIPMENT
Bring sturdy walking boots, weatherproof clothing, a hand lens and a camera or phone. A small ruler makes a useful photographic scale. Carry drinking water and a map or downloaded route information; keep both hands free on the steps and uneven paths.
Rock-breaking tools are inappropriate for an observation visit to this reserve. There is no need to split shale or excavate scree to enjoy the fossils here.
CLEANING AND TREATING
Leave fossils and rock surfaces undisturbed in the reserve. Photograph what is already visible rather than brushing, scraping or washing an exposure.
For an existing lawfully obtained limestone specimen, start with a soft dry brush. Fossil calcite and the surrounding limestone can break together, so forcing away hard matrix may destroy the feature you want to reveal. Any detailed mechanical preparation should be done cautiously under magnification. Avoid household acids, bleach and varnish, and seek specialist advice before preparing a potentially important coral or a specimen with reliable bed information.
IDENTIFY YOUR FINDS
Need help identifying a fossil? Share clear photos, where you found it and its size with the community.
FURTHER READING
Cumbria Wildlife Trust: Clints Quarry visitor information
Geological Conservation Review: Clints Quarry and the Lower Carboniferous of west Cumbria
BGS: Eskett Limestone Formation
BGS: Geology of the west Cumbria district
Cumberland Geological Society: White Limestone cycles and the Clints field excursion
Natural England: Clints Quarry SSSI citation
ACCESS RIGHTS
Clints Quarry is a Cumbria Wildlife Trust nature reserve within Clints Quarry SSSI. The reserve’s paths are open to visitors, subject to on-site notices. Stay on the signed route, leave rock, fossils and vegetation undisturbed, and ask the Trust before any proposed sampling or removal.
The protected geological interest includes the Carboniferous succession, fossils and ancient dissolution surfaces. SSSI designation does not give permission to enter adjoining land or to collect from the quarry faces. Follow the reserve’s current visitor guidance and any directions from the landowner or reserve manager.
It is important to follow our ‘Code of Conduct’ when collecting fossils or visiting any site. Please also read our ‘Terms and Conditions‘
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