High Fell Quarry, above Tilberthwaite, reveals the volcanic origins of Lakeland slate. Quarry working restarted under a new tenant in 2023. Climbing advice warned of intended renewed blasting and advised people to keep away. Stay on public paths and out of the workings; seek the landowner’s permission before any proposed quarry visit or sampling.
FIND FREQUENCY: ♦ – A geological observation locality rather than a reliably documented fossil or crystal-collecting site. No exact-quarry fossil occurrence or collectable mineral inventory was verified.
CHILDREN: ♦ – Steep slate spoil, quarry edges and industrial workings make the quarry unsuitable for children’s collecting.
ACCESS: ♦♦♦ – The valley is reached from Tilberthwaite parking, but a walking route does not give access to quarry workings or spoil.
TYPE: – Recently worked slate quarry, with older workings and moved spoil. Public-path access is separate from quarry-entry permission.
DIRECTIONS
♦ From the A593 north-east of Coniston, take the signed single-track road towards Tilberthwaite just beyond Yew Tree Farm when travelling from Coniston. Follow it for about a mile to the National Trust parking area.
♦ Use mapped public paths in the High Tilberthwaite valley and follow current signs. Do not enter quarry works, cross barriers or use spoil slopes as a shortcut. The National Park’s High Tilberthwaite walking route provides valley orientation, not permission to enter High Fell Quarry.
♦ The quarry is recorded by BGS at NY 305 021. The original UK Fossils reference is 54.40979°N, 3.07159°W; this locates the quarry area rather than an authorised entrance.
♦ Ask the landowner before planning access to the quarry or spoil areas, and confirm arrangements with the quarry tenant where working areas are involved.
FOSSIL HUNTING
High Fell is most useful for understanding slate and volcaniclastic rocks. No exact-quarry fossil occurrence has been verified, and the older guide’s promise of a wide range of collectable minerals is not supported by a reliable locality-specific mineral list. Plan an observation visit from public paths unless the landowner has agreed to a more detailed geological visit.
Look for contrasts between fine, evenly splitting slate and coarser, fragment-rich material visible in existing exposures or photographs. A sandstone made largely from volcanic debris can preserve sand-sized grains and rock fragments; a breccia contains larger angular pieces. These textures tell a geological story even when no distinct crystal or fossil is present. Colour alone is not a dependable mineral identification, particularly where weathering has stained a rock surface.
The flat surfaces that make slate useful for roofing are chiefly cleavage planes produced during later deformation. They are not automatically the layers in which the sediment was deposited. Where the distinction is visible from a safe position, compare the repeated splitting direction with any changes in grain size, colour or fragment abundance. Do not split rock or approach a quarry face merely to obtain a clearer view.
Quarry spoil consists of moved, mixed and broken material. A fragment lying on a heap may illustrate slate cleavage or a volcanic clast, but its position does not identify its original bed. Do not climb the heaps, pull out supporting blocks or turn over unstable slabs. The large piles are part of an industrial site and should not be treated as freely available collecting ground.
A hand lens and photographs with a scale are useful for recording permitted observations. Note whether the rock was seen in place or in spoil, and retain that distinction when seeking an identification. Mineral lists from nearby copper mines and fossil reports from other parts of the Borrowdale Volcanic Group cannot be transferred to High Fell. If a potentially interesting feature is found during an authorised visit, record it where it lies and ask before removing material.
Significant discoveries, geological research and conservation milestones at High Fell Quarry.
1994 – The quarry is recorded in a heritage survey
A survey recorded High Fellside as a modern slate quarry, preserving a dated account of the industrial landscape.
1999 – Updated planning conditions are granted
A temporary consent dated 24 November 1999 set updated conditions for High Fellside. Its historic expiry date does not establish whether working has ceased today.
2010 – BGS records the exact quarry rock
The national quarry directory identifies High Fell at NY 305 021 as volcaniclastic sandstone and breccia of the Seathwaite Fell Sandstone Formation.
2012 – A mining-history visit distinguishes old and working quarries
A 15 April visit recorded the old quarry and mill, newer working to the south and the separate Betsy Crag workings to the north. These were different parts of the industrial complex.
2020 – A landscape survey records active use
A National Trust survey described an active quarry, with modern buildings in use among older structures and spoil.
2023 – Working restarts under a new tenant
Specialist access accounts report renewed tenancy and working in 2023. An exact-quarry notice about the new tenancy warned of intended renewed blasting, prohibited climbing and advised people to keep away. The notice concerns quarry access and climbing; it does not establish a blanket closure of the valley’s public paths.
GEOLOGY
BGS identifies the High Fell quarry rock as volcaniclastic sandstone and breccia of the Seathwaite Fell Sandstone Formation, within the Borrowdale Volcanic Group. This exact-quarry assignment replaces the Duddon Hall Tuff attribution in older descriptions. The formation belongs to the Ordovician volcanic history of the Lake District; the BGS Lexicon uses the historical regional age term Caradoc for it.
Volcaniclastic rocks contain material derived from volcanic activity, but that does not mean every bed was deposited directly by an eruption. Much of the Seathwaite Fell succession records ash and volcanic fragments reworked by water into sandstone, siltstone, conglomerate and breccia. Continued eruptions also supplied fresh ash and lapilli, the coarser particles between ash and larger blocks. Different transport and settling processes produced changes in sorting, grain size and bedding.
In the Coniston–Tilberthwaite district, the wider formation preserves rapid underwater sedimentation as well as channel deposits. BGS records a breccia-filled channel and separate graded tuff beds at precisely located nearby exposures. These help explain the variety of rock in the district, but they are not a measured log of High Fell Quarry and are not presented as accessible collecting targets. No formal member sequence or reliable bed-by-bed quarry thickness is established here.
Long after deposition, deformation and low-grade alteration produced the cleavage that allows suitable rock to split into slate. Bedding records the original accumulation of sediment; cleavage records the later response to pressure and deformation. Quarrying has since excavated the usable stone and left large quantities of mixed spoil, so the visible landscape combines an ancient volcanic-sedimentary history with much younger industrial disturbance.
Detailed geology, slate cleavage and the limits of the High Fell quarry section
BORROWDALE VOLCANIC GROUP
High Fell lies within the Ordovician volcanic and volcaniclastic succession of the Lake District. The group includes rocks formed directly by eruptions and rocks made from volcanic material subsequently moved and deposited by water. Membership of this broad group does not establish a particular mineral or fossil occurrence in the quarry.
Seathwaite Fell Sandstone Formation
Exact-quarry assignment. The BGS Directory of Mines and Quarries identifies High Fell Quarry, High Fellside, High Tilberthwaite, at NY 305 021 as volcaniclastic sandstone and breccia of this formation. It is the strongest exact-quarry stratigraphic assignment recovered. The earlier Duddon Hall Tuff attribution is not used here.
Age, lithology and scale. The BGS Lexicon uses the historical Caradoc age term. The formation comprises bedded volcaniclastic sandstone and siltstone, with tuff, lapilli-tuff, breccia and conglomerate. Its regional thickness range of approximately 30–1100 m reflects large changes across the district; it is not a measurement of High Fell Quarry. No reliable exact-quarry bed numbering or measured complete section has been established.
Depositional setting. In the Coniston–Tilberthwaite area, volcanic debris was reworked into water-laid sediment while eruptions continued to add ash. Rapid subaqueous deposition and later channel development produced marked changes in grain size and sorting. A volcanic fragment in a sedimentary rock is evidence of its source, not proof that the enclosing bed was deposited directly from an eruption.
Bedding and slate cleavage. Grain-size changes, grading and stratification belong to the original depositional fabric. Later deformation and alteration produced a penetrative cleavage through suitable fine-grained rocks, allowing them to split into slate. Cleavage can cross bedding, so the thickness of a loose slate slab is not a sedimentary bed measurement.
Limits to subdivision. The Ambleside memoir notes that outside the Central Fells the formation was not formally divided into members. Named units such as Cam Crags, Dungeon Ghyll, Pavey Ark, Bowfell Links, Cockly Pike and Sprinkling Tarn must not be inserted into a High Fell column merely because they occur elsewhere in the formation. The finest defensible quarry account here is formation and lithofacies level.
Nearby High Tilberthwaite channel, NY 3040 0192. BGS records a steeply incised channel filled by chaotic polymict breccia, containing a mixture of clast types. This is a precisely located nearby observation, not a bed measured in the High Fell visitor spoil. The memoir’s maximum channel depths of about 10 m describe regional examples and are not a separate measured High Fell thickness.
Nearby graded tuff beds, NY 3037 0171. A separate mapped exposure contains parallel-bedded, well-sorted andesitic coarse tuff and fine lapilli-tuff. Individual beds reach 0.30 m and show normal, reverse or multiple grading. The memoir interprets these as ash-fall deposits. This local measurement belongs to the stated grid reference, not to an invented quarry log or an authorised visitor target.
Quarry spoil. The heaps around the workings are human-made accumulations of moved and mixed rock. They belong to the industrial landscape, not a separate Ordovician stratigraphic bed. Their position cannot establish the original horizon of an individual fragment, and geological interest does not establish permission to enter or collect.
Fossil and mineral limits. No exact-quarry fossil occurrence or dependable collectable-mineral list was verified. Regional microscopic records of feldspar, volcanic fragments and alteration minerals do not prove that recognisable mineral specimens can be collected here. Fossils reported at Brandy Crag or Walna Scar, and mineral lists from nearby copper mines, are separate locality records.
References.
Cameron and colleagues (2010), BGS Directory of Mines and Quarries, High Fell entry, p. 1-117.
BGS Lexicon: Seathwaite Fell Sandstone Formation.
Millward and colleagues (2000), Geology of the Ambleside district, especially Chapter 6.
National Trust heritage record MNA119780.
Cumbria Amenity Trust Mining History Society Newsletter 109 (2012), High Fell and Betsy Crag field visit.
SAFETY
Treat High Fell as a recently worked quarry. A National Trust survey recorded active workings in 2020, and later specialist access information reports renewed working under a new tenant in 2023. An exact-quarry notice from the Fell & Rock Climbing Club about the new tenancy warned of intended renewed blasting, prohibited climbing and advised people to keep away. This is not evidence that blasting is taking place on the day of a visit, but it is a clear reason to stay out of working areas. Follow signs and barriers, and do not infer that quiet conditions mean entry is permitted.
Sharp slate, slippery slabs, unstable spoil, vertical faces, sudden drops and water-filled workings make off-path exploration hazardous. Do not climb heaps, walk close to quarry edges, enter tunnels or adits, or stand below rock faces. Wet slate can be especially treacherous.
Wear suitable walking footwear and clothing for changeable fell weather. Keep to an agreed route during any authorised visit and turn back when conditions or operations make access unsafe. Climbing approaches described for neighbouring Runestone Quarry are not visitor routes into High Fell.
EQUIPMENT
For viewing from public paths, bring sturdy boots, weatherproof clothing, a map, a hand lens and a camera. A small scale is useful for any photographs that can be taken without leaving the route.
Do not bring a pick or hammer on the assumption that collecting is permitted. Any specialist visit, sampling equipment or protective equipment must be appropriate to arrangements agreed with the landowner and quarry tenant.
CLEANING AND TREATING
Leave rock and spoil untouched unless removal has been expressly agreed. For an existing lawfully obtained slate specimen, use a soft dry brush first and avoid forcing apart thin cleavage surfaces. Fragile edges may flake during washing or handling.
Keep labels recording the exact source and whether a specimen came from spoil. Avoid acids, bleach, varnish and aggressive scrubbing; the mineral identity and the stability of the rock should be understood before any further treatment.
IDENTIFY YOUR FINDS
Need help identifying a fossil? Share clear photos, where you found it and its size with the community.
FURTHER READING
BGS Lexicon: Seathwaite Fell Sandstone Formation
BGS: Geology of the Ambleside district
National Trust heritage record: High Fellside Slate Quarry
National Trust: Tilberthwaite valley approach and walking information
Cumbria Amenity Trust Mining History Society: High Fell and Betsy Crag visit, 2012
ACCESS RIGHTS
Keep to public paths and follow signs around the working quarry. Ask the landowner before entering quarry or spoil areas or taking specimens. National Trust ownership and the quarry tenancy are separate considerations; a public path does not provide unrestricted access to industrial land.
The climbing notice about the new tenancy advises people to keep away from High Fell and warns of intended renewed blasting. Its climbing prohibition is not a blanket closure of every public path, but no quarry-entry or collecting permission should be inferred from the route. Confirm current arrangements with the landowner and quarry tenant before proposing a specialist visit, and respect any refusal or operational restriction.
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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