The Valley of the Rocks, just west of Lynton, exposes fossil-rich Devonian sandstone and slate in a striking coastal dry valley. Weathered loose pieces can show brachiopods, crinoid fragments and delicate fossil impressions, while Castle Rock and Rugged Jack reveal the harder beds. Paths and car parks make the valley easy to reach, but the scree, crags and seaward drops need care.
FIND FREQUENCY: ♦♦♦♦ – Fossil impressions and crinoid fragments occur in the Lynton Formation, although many are small, incomplete or distorted.
CHILDREN: ♦♦♦ – The lower valley paths suit a supervised family visit; steep scree, rock towers and unguarded coastal drops do not.
ACCESS: ♦♦♦♦♦ – Roadside car parks give straightforward access to the valley. The fossil-bearing loose ground is uneven and is not accessible to everyone.
TYPE: Devonian sandstone and slate outcrops with loose scree. Visit without damaging the crags, vegetation or protected rock surfaces.
DIRECTIONS
♦ Head to Lynton from the A39 on the B3234, then follow the signs through Lynton to the Valley of the Rocks.
♦ Continue west along the valley road. Existing car parks serve the eastern and western parts of the valley; the western parking is closer to Castle Rock and the loose slopes described below.
♦ The Exmoor National Park Authority car park beside the public toilets uses postcode EX35 6JH. It is pay and display; other valley car parks have separate management, so check the signs where you park.
♦ Use the established valley paths to examine loose material at ground level. There is no need to climb the rock towers or take the exposed seaward path to appreciate the fossils.
♦ Ref: 51.23231°N, 3.85229°W
FOSSIL HUNTING
The useful material is the grey, fine-grained to gritty sandstone and slaty rock naturally shed from the Lynton Formation. The original collecting area is on the north side of the valley around Castle Rock and Rugged Jack, including loose pieces beside the paths west of the western car park. Examine naturally exposed surfaces at the foot of the slopes rather than climbing into loose scree. Keep the association between a find and its exact part of the valley: a loose fragment has already moved from its bed and cannot automatically be assigned to a precise horizon.
Crinoids are a particularly rewarding feature. Look for small disc-like or ring-like impressions, sometimes crowded across a bedding surface, and occasional short jointed stem fragments. Many specimens are natural moulds left after the original skeleton dissolved, so a shallow hollow can be more informative than a projecting fossil. The valley has yielded numerous columnals identified as Hexacrinites sp. D, as well as Cupressocrinites sp., Annulocolumnus and Pentagonocyclicus. These are research identifications of stem elements; an isolated ring is usually best recorded simply as a crinoid columnal unless its detailed joint surface can be compared with illustrated material.
Brachiopods are preserved as shells or impressions with curved outlines and, in some examples, radiating ribs. Survey collections from the south side of the valley include Subcuspidella lateincisa; north-side material includes Chonetes sordidus and forms compared with Subcuspidella lateincisa. Cleavage and distortion can make identification difficult, and the flat surface along which a rock has broken is not always its original bedding plane. Keep both parts of a naturally split specimen when this is permitted, as the impression and its counterpart may retain different details.
Bivalves add variety to the shelly assemblages. The south and south-west valley collections contain Palaeoneilo compared with P. primaeva, with other records compared with P. maureri and Paracyclas rugosa. These qualified identifications should not be turned into promises of easily recognisable species. Delicate fenestellid bryozoans can leave a net-like pattern; their fine branching mesh is easily damaged. Phillips recorded abundant material under the historical name Fenestella antiqua here in 1841, but that old name is not a secure modern identification for every meshwork fragment.
Burrows and other traces record activity within the sediment rather than the animal itself. Branching traces such as Chondrites are characteristic of the formation, and the survey recorded indeterminate borings in south-side valley material. Distinguish these from the regular joints of a crinoid stem or the repeated mesh openings of a bryozoan. Microscopic plant spores have also been recovered from a north-side rock sample, but this does not mean that recognisable plant fronds are a common visitor find. A hand lens, low-angle light and a photograph with a scale often reveal more than further preparation.
A chronological record of fossil discoveries, geological research and conservation at the Valley of the Rocks.
1841 – Fossil-rich valley beds described
John Phillips described abundant bryozoans and crinoid fragments in fine-grained slaty beds near the entrance to the valley, and noted that cleavage made good specimens difficult to extract. His account provides an early detailed record of the locality’s fossil-bearing rocks.
1953 – Marine capture proposed
S. Simpson interpreted the dry valley as part of a formerly more extensive west-flowing river system, shortened by coastal erosion and capture. This became a major explanation of the valley’s unusual position beside the sea.
1966 – An ice-marginal drainage alternative
N. Stephens proposed that water overflowing from a lake held back by ice on the north Devon coast could have cut the dry valley. This offered an alternative to river capture and linked the landform to the debated extent of Pleistocene ice.
1980 – The buried rock floor investigated
D. Dalzell and E. M. Durrance used electrical resistivity to examine the thick deposits beneath the valley. Their reconstruction revised the simple former-river route through Lee Abbey and showed why the modern ground surface alone cannot reveal the original drainage pattern.
1985 – Precisely located fossil assemblages recorded
The geological survey memoir documented separate south-west, south and north valley fossil collections, together with a north-side plant-spore sample. These located records allow the valley’s fauna to be distinguished from fossils found elsewhere along the Lynton Formation outcrop.
1986 – Geology and habitats protected together
The West Exmoor Coast and Woods designation, notified on 4 March, included the valley’s fossiliferous Devonian exposures, dry-valley landforms and associated periglacial features alongside its important wildlife and lichen interest.
2015 – Crinoid stem fragments studied in detail
Fiona Fearnhead and Stephen Donovan described a new collection rich in Hexacrinites sp. D and other crinoid ossicles. They reported the first proximal stem columnals of Hexacrinites from the Devonian type area and identified a Cupressocrinites specimen as the oldest then known from the British Isles. Small sandstone moulds had proved useful for much more than a general identification as crinoid debris.
2021 – Valley specimens included in a modern crinoid monograph
Stephen Donovan and Fiona Fearnhead illustrated and treated Valley of Rocks material in their revision of British Devonian crinoids, including Hexacrinites, Cupressocrinites, Annulocolumnus and Pentagonocyclicus. The specimens provide reference material for comparing incomplete stem and arm remains.
GEOLOGY
The crags belong to the Lynton Formation, historically called the Lynton Beds or Lynton Slates. This is a marine succession near the Early–Middle Devonian boundary; the BGS gives an Emsian to Eifelian age range. At the valley, resistant quartz-rich sandstone beds alternate with finer slaty material. Castle Rock, Rugged Jack and the Devil’s Cheesewring owe their prominence to these harder rocks, while less resistant material has weathered into the valley slopes and their loose debris.
The original deposits were sand, silt and mud laid down in a shallow sea. Quiet intervals allowed fine layers to accumulate; changes in water energy, shell concentrations and burrowing disturbed or reworked some of those surfaces. Subsequent compression folded the succession around the Lynton anticline and imposed cleavage, a later splitting fabric that can cross the bedding and distort fossils. This is why a fresh-looking rock face may reveal less detail than a naturally weathered surface, and why forcing a fossil from the slaty matrix often breaks it.
The dry valley is much younger than its Devonian rocks. Its origin remains debated: marine erosion may have captured and shortened an older river system, or ice-marginal drainage may have cut or modified the channel. Geophysical work showed that thick superficial deposits conceal the original rock floor, complicating interpretations based only on today’s valley shape. Cold-climate frost shattering and downslope movement contributed scree and head; these loose deposits contain fragments of much older fossil-bearing bedrock. They are not a second Devonian fossil formation.
Detailed geology of the Valley of the Rocks, with locally documented fossil horizons and younger valley deposits.
Lynton Formation
The local bedrock is Devonian sandstone, siltstone and slate within the Emsian–Eifelian range given by the BGS. “Lynton Beds” and “Lynton Slates” are historical names for the same succession, not additional units. No formal member or parent group is assigned in the current BGS Lexicon entry. Its regional thickness estimate of about 300–400 m is not a measured thickness exposed in this valley.
Resistant sandstone beds and interbedded slate
The arenaceous beds form Castle Rock, Rugged Jack and the Devil’s Cheesewring. Fairly massive quartzitic sandstone alternates with finely laminated slaty rock. Cleavage and burrowing obscure parts of the original sedimentary structure. The available locality evidence does not establish a continuous numbered log or reliable thickness for each valley bed, so these outcrops should not be presented as an invented member-by-member stack.
More slaty beds at South Cleave
The BGS records more slate-rich beds at South Cleave, SS 7065 4945, contrasting with the resistant sandstone crags. This exposure is separately located from fossil sample G at SS 7065 4955. The slaty tract can be followed eastwards only through scattered exposures; fossils reported farther along that tract near Brendon should not be attributed to the valley.
South-west valley fossil-bearing material
Survey locality F, at SS 7029 4939, yielded crinoid columnals, indeterminate spiriferacean brachiopods and bivalves. The identifications include Palaeoneilo cf. maureri, Palaeoneilo cf. primaeva and Tancrediopsis aff. subcontracta. The same sample includes historical determinations recorded as Myophoria, Nuculana and a questionable Myilarca; these should remain provisional rather than being silently converted to modern species. The qualifications indicate resemblance rather than certain species assignments. This is a geographically located sample assemblage, not a named bed with a measured position in a complete section.
South-side fossil-bearing material
Survey locality G, at SS 7065 4955, records Subcuspidella lateincisa, Palaeoneilo cf. primaeva, Paracyclas cf. rugosa, indeterminate fenestellid bryozoans, a questionable chonetacean, crinoid columnals and borings. A record compared with Ptychopteria (Actinopteria) spinosa is doubtful. The associated fossils help distinguish a marine shell-bearing assemblage from the apparently featureless broken sandstone around it.
North-side fossil-bearing material
At SS 7097 4993, survey locality H yielded Chonetes sordidus, indeterminate strophomenoids, a questionable Mauispirifer and material compared with Subcuspidella lateincisa. A separate north-side sample at SS 7086 4992 contained carbonised spores probably referable to Hystricosporites. These fossil records cannot be arranged into a precise vertical sequence solely from their positions around the valley.
Crinoid-rich sandstone surfaces
Modern study has documented mouldic crinoid stem ossicles in the valley’s Lynton Formation. Hexacrinites sp. D occurs abundantly in the studied material. Other illustrated forms include Cupressocrinites sp., Annulocolumnus (col.) sp. cf. A. (col.) annulus, Pentagonocyclicus (col.) sp. A and arm ossicles. A root-like attachment element (radice) with a figure-of-eight-shaped axial canal was also recorded. These records extend the useful fossil evidence beyond the old guide’s general “crinoids”, but do not establish a separately named bed or a guaranteed species identification for every loose fragment.
Structure and correlation limits
The valley lies near the Lynton anticline. Local bedding inclinations between Wringcliff Bay and Hollerday Hill were recorded at about 6–15°, with roughly 7° eastward or east-south-eastward dips on parts of the northern slopes. These local readings are not a single attitude for every exposure. The survey could not relate all fossil localities to a standard sequence. The formation’s base and its regional transition into the Hangman Sandstone are not a complete pair of exposed contacts in this valley guide.
Quaternary scree and head
Angular sandstone and slate fragments mantle the slopes and merge downslope into finer-rich head, material moved under cold-climate conditions. Much of this cover has been interpreted as Devensian in age. Fossils within it are reworked from the Devonian bedrock: the age of a fossil and the age of the loose deposit carrying it are very different.
Upper coarse cover
Electrical-resistivity interpretation identified a western surface layer of boulders and blocks averaging about 2–5 m thick, with a finer equivalent at the eastern end. This coarse cap is part of the superficial fill, not an additional 2–5 m to add to its quoted total thickness.
Deeper fine-rich fill and total superficial thickness
Most of the deeper fill was interpreted as fine-rich solifluction material derived from the valley sides. The total superficial cover, including its coarse cap, was interpreted as increasing westwards from about 27 m at the valley-floor high point to about 35 m at the lower point. These are subsurface estimates, not thicknesses of beds continuously exposed beside the footpath; marine erosion and mass movement further complicate the western rockhead profile.
Why the valley is dry
Marine capture and ice-marginal drainage are the principal competing explanations. In 1980, reconstruction of the buried rock floor led to a revised river-capture model: the former main river was interpreted as passing towards present Wringcliff Bay, while the Lee Abbey gap carried a tributary. This differed from the older idea of one river flowing through both gaps. The detailed numbered Quaternary section at Lee Bay belongs to that neighbouring shore and is not a measured succession within the Valley of the Rocks.
References
Edmonds, Whittaker & Williams (1985): Geology of the country around Ilfracombe and Barnstaple
BGS Lexicon: Lynton Formation
Campbell (1998): The Valley of Rocks, Quaternary of South-West England
Fearnhead & Donovan (2015): Fossil crinoids from the Valley of Rocks
Donovan & Fearnhead (2021): The British Devonian Crinoidea, Part 2
SAFETY
Keep to established paths and stable ground. Loose scree can move underfoot and material can fall from the crags above; do not climb the slopes or stand directly beneath rock faces to search. No particular slope angle makes scree safe.
The seaward side has narrow, exposed paths and sudden drops. Supervise children closely, keep away from cliff edges and avoid exposed routes in strong wind or poor visibility. A fossil visit can remain on the lower valley paths; descending to Wringcliff Bay is a separate coastal outing with additional tide and cliff hazards.
EQUIPMENT
Take sturdy footwear with a good grip, a hand lens and a camera with a scale. A small torch helps show shallow moulds in low-angle light. A notebook or phone record of the exact find position is scientifically useful. Bring paper wrapping and a rigid box only if current permission allows a small loose specimen to be removed. Hammers and chisels are unnecessary for the non-damaging visit described here.
CLEANING AND TREATING
Many valley fossils are fragile impressions in sandstone or slaty matrix. For an authorised loose find, begin with careful dry brushing and let a wet specimen dry slowly at room temperature. Do not scrub delicate bryozoan meshwork or scrape crinoid moulds; cleaning away their surface may remove the fossil itself.
Avoid acids, bleach, varnish and forceful splitting along cleavage. Leave a potentially important or unusually complete fossil unprepared, photograph it with a scale and seek specialist advice. Retaining the surrounding matrix and the original locality record is more valuable than trying to expose every detail.
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: Lynton Formation
Edmonds, Whittaker & Williams (1985): Geology of the country around Ilfracombe and Barnstaple
Campbell (1998): The Valley of Rocks, Quaternary of South-West England
Fearnhead & Donovan (2015): Fossil crinoids from the Valley of Rocks
Donovan & Fearnhead (2021): The British Devonian Crinoidea, Part 2
Exmoor National Park: The Valley of Rocks
ACCESS RIGHTS
The Valley of the Rocks lies within the West Exmoor Coast and Woods SSSI, designated for both geological and biological interest. Respect rock surfaces, lichens and vegetation as well as fossils. Use the established paths and do not hammer, prise material from the crags, dig into scree or disturb archaeological features.
Public access is not blanket permission to remove specimens. Check the current land-manager guidance and any signs before taking even loose material; where permission is unclear, leave it in place and record it photographically. The original SSSI citation explains the scientific interest but is not a collecting permit.
Original designation document: SSSI Information – Valley of the Rocks
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