The rugged shore north of Camustianavaig rewards careful observation with Jurassic ammonites and large fossil shells, set beneath the dramatic slopes of Beinn Tianavaig. Fossil-rich blocks, dark shale and younger plant-bearing rocks tell several different chapters of Skye’s geological history. The narrow coastal path and boulder-strewn shore make this a demanding outing for experienced walkers.
FIND FREQUENCY: ♦♦♦♦ – Fossiliferous blocks occur along the shore, but exposure varies and the walk itself is demanding.
CHILDREN: ♦ – The narrow, exposed path and rough boulders make the fossil route unsuitable for young children.
ACCESS: ♦♦ – A coastal walk from Tianavaig Bay, with awkward footing and tidal obstacles; allow plenty of time for the return.
TYPE: Cliffs and foreshore; examine accessible rock surfaces and loose blocks without approaching unstable cliff faces.
DIRECTIONS
♦ From the A87 south of Portree, take the B883 towards Braes and follow the turnings for Camustianavaig rather than Penifiler. Continue down the minor road to Tianavaig Bay. Use the small shore-side parking area by the picnic tables, keeping access to homes, gates and the road clear. Space is limited: do not park in passing places, and follow any current parking notices.
♦ The published reference, 57.37248°N, 6.14573°W, marks the bay parking and starting area, rather than an individual fossil exposure. From here, cross the burn on the foreshore when conditions allow and head north along the upper shore. Pick up the narrow coastal path as it rises around the headland, then follow it north below Ben Tianavaig towards the grassy ground and boulder-strewn shore. The separate hill path from the village leads towards the summit and is not the fossil-shore approach.
♦ Allow roughly 40 minutes for the outward approach, with extra time for difficult ground and the return. Conditions and your pace may make it considerably longer. The path is narrow and exposed in places, and the beach section is affected by the tide. Check current wildlife notices before continuing beyond the bay, and return the same way only while the route remains safely passable.
FOSSIL HUNTING
The most useful search area is the loose material on the shore beyond Creagan na Sgalain. Where access and collecting are permitted, examine existing weathered faces of small fallen blocks rather than the cliffs or bedrock. Different rocks and ages are mixed together by landslipping and waves. Photograph a promising specimen with its surrounding rock and record exactly where the loose block was found; its beach position alone does not identify its original bed.
Ammonites. Look for regularly coiled outlines and repeated ribs on grey, mica-bearing, fine-grained limestone surfaces. Several small ammonites can occur together in one band. The published Beinn Tianavaig assemblage includes Dactylioceras toxophorum, Harpoceras serpentinum and Hildaites, but a worn spiral or partial whorl rarely justifies a species name. Keep any natural matching pieces together. The formation of origin of this ammonite-rich horizon remains uncertain between the uppermost Scalpay Sandstone and Portree Shale.
Scallops, oysters and brachiopods. Yellowish calcareous sandstone and sandy shale at the headland contain the large scallop-like bivalve Pseudopecten aequivalvis, the oysters recorded as Gryphaea cymbium and G. gigantea, and the brachiopod Tetrarhynchia tetrahedra. Broad fan-shaped outlines with radiating ribs are a useful clue to scallops; strongly curved valves suggest oysters. Brachiopods are a separate animal group, despite also possessing two shells. Use these shapes as starting points, not as a substitute for checking the full specimen.
Belemnites and concretions. Tapering, bullet-like guards and their broken cross-sections can be easier to recognise than incomplete ammonites. Belemnites are specifically recorded in the younger marine sandstone north of the headland. Rounded or flattened doggers are hard patches of cemented sediment; their shape alone does not make them fossils. Check naturally exposed surfaces for shell outlines before assuming that a nodule contains a specimen.
Plant remains. Thin dark films and fragments can occur in the plant-bearing flaggy beds and carbonaceous sediments. Look for a repeated organic structure rather than identifying every black streak as wood or a fern. Palaeocene plant beds occur directly above the Jurassic succession here, so retain a cautious age and identification for loose plant-bearing material. Small, well-recorded examples or photographs are much more useful than an unmanageable block carried over difficult ground.
A chronological record of geological research and scientific milestones on the Camustianavaig shore.
1873 – Jurassic sections described
James Bryce’s study of Skye and Raasay included the Camastianavaig coastal section. It established an early published record of the fossil-bearing sedimentary rocks on this shore, subsequently revisited during Geological Survey mapping.
1896 – Jurassic outcrops mapped
H. B. Woodward mapped the Middle Lias outcrops along the east-Skye coast, including the stretch from Camastianavaig northwards. This provided a geological framework for separating the marine sandstone from the surrounding volcanic rocks and disturbed ground.
1901 – Phosphatic erosion surface documented
Horace B. Woodward described a thin, phosphatic, ooidal layer beneath the basal Inferior Oolite sandstone at the southern end of the Beinn Tianavaig cliffs. He recognised that the sandstone occupied a hollow eroded into older shale. The layer’s shell fragments, echinoderm debris and foraminifera helped characterise this distinctive marine horizon.
1920 – Large coastal landslips recorded
G. W. Lee documented the large landslips at Beinn Tianavaig affecting both Jurassic strata and basalt. This early account highlighted the structural disruption that makes the present coastal succession difficult to trace and measure.
1966 – Headland succession measured and plant beds clarified
A detailed account recorded the fossiliferous sandstone and crushed Toarcian shale at Creagan na Sgalain, together with the section north of the point. Seven numbered plant-bearing sedimentary beds and two dolerite sills were logged above the Jurassic sandstone. The local coal-bearing beds were distinguished from the much older Jurassic oil shale.
2004 – Ammonite-bed correlation reassessed
A stratigraphic review recorded Dactylioceras toxophorum, Harpoceras serpentinum and Hildaites in silty limestone east of Beinn Tianavaig. It considered whether this ammonite-rich horizon belongs to the uppermost Scalpay Sandstone or the Portree Shale, favouring the former while explicitly leaving the correlation unresolved.
2018 – Plant-bed microfossils investigated
A published investigation examined two sandstone samples from the Palaeocene plant beds near Camas Tianavaig. One yielded a sparse assemblage of fungal material and pollen. The remains confirmed a microscopic plant record, but their low abundance and long stratigraphic ranges prevented a precise age determination.
GEOLOGY
The shore around Creagan na Sgalain, on the north side of Tianavaig Bay, exposes a broken succession of Jurassic marine rocks beneath much younger Palaeocene sediments and volcanic rocks. The fossil-bearing Jurassic beds include the upper Scalpay Sandstone Formation, a disturbed Toarcian shale interval and the basal part of the Bearreraig Sandstone Formation. Landslipping, intrusive dolerite and fallen blocks interrupt the succession, so a walk along the beach is not a simple journey through an undisturbed geological sequence.
The Scalpay Sandstone is the older, mainly late Pliensbachian part of the exposed marine succession. At the headland it consists of yellowish, lime-rich sandstone and sandy shale, with large scallop-like Pseudopecten aequivalvis, oysters and brachiopods. Hard calcareous concretions, traditionally called doggers, occur in the sandstones farther north. Only the upper part of the formation is exposed here; its regional thickness must not be mistaken for a measured thickness at this shore.
The ammonite-rich rocks require particular care. Grey, mica-bearing silty limestone crowded with small ammonites is documented east of Beinn Tianavaig, with records of Dactylioceras toxophorum, Harpoceras serpentinum and Hildaites. Its precise position remains unresolved: it may lie at the top of the Scalpay Sandstone or within the Portree Shale Formation. The published interpretation favours the former but does not establish it conclusively. A thin ammonite-rich band in a loose block therefore cannot be used to identify the whole Portree Shale succession.
The Geological Survey recorded about 3.7 m of disturbed Toarcian shales at Creagan na Sgalain and about 1.5 m roughly 365 m farther north. These are incomplete, crushed exposures, not reliable original formation thicknesses. At the northern section, about 4.6 m of younger marine sandstone with doggers and belemnites overlies a phosphatic basal horizon. These beds belong to the local remnant of the Bearreraig Sandstone succession, historically called the Inferior Oolite.
An erosion surface separates the Jurassic rocks from the Palaeocene plant beds of the Portree Hyaloclastite Formation. Sandstone, carbonaceous shale, thin flaggy beds and coal are recorded here, with dolerite sills intruded between some beds. Volcanic deposits and the basaltic lavas of the Beinn Edra Formation complete the higher ground. Consequently, plant remains in a loose shore block cannot automatically be assigned to the Jurassic. Later landslides displaced both the sedimentary and volcanic rocks and produced the confused, boulder-strewn coast seen today.
The detailed succession at Creagan na Sgalain, including the Jurassic fossil beds and younger plant-bearing strata.
This account follows the shore at Creagan na Sgalain and the measured section approximately 400 yd (365 m) north of it. It is arranged from older to younger rocks. Published thicknesses describe particular exposures, many affected by landslip, and are not a single complete vertical log. Formal members have not been established confidently for this exact section.
LIAS GROUP
The local Lower Jurassic marine succession includes the upper Scalpay Sandstone and the overlying Toarcian shale interval. Historical accounts call these the Middle and Upper Lias respectively. These older terms should not be confused with the modern Middle and Upper Jurassic.
Scalpay Sandstone Formation
The headland exposes only the upper part of this formation. The local sandy succession is chiefly late Pliensbachian, although the formation extends into the early Toarcian regionally. Its lower boundary and complete thickness are not exposed on this shore.
Shell-bearing sandstone and sandy shale at Creagan na Sgalain. Yellowish calcareous sandstone and sandy shale emerge at shore level. The documented fossils are Pseudopecten aequivalvis, Gryphaea cymbium, G. gigantea and Tetrarhynchia tetrahedra. These are records from the headland itself.
Dogger-bearing sandstone north of the headland. About 400 yd farther north, sandstone contains calcareous doggers. Beyond this, scree and landslide debris conceal most of the formation, with only isolated reefs of sandstone visible on the beach. The doggers are concretions formed by cementation within the sediment.
Ammonite-rich silty limestone: uncertain formation assignment. Grey micaceous silty limestone crowded with small ammonites is documented in outcrops east of Beinn Tianavaig. The reported assemblage includes Dactylioceras toxophorum, Harpoceras serpentinum and Hildaites sp. The Geological Conservation Review considers two possibilities: a bed within the Portree Shale Formation, or the equivalent of Bed 6 at the top of the Scalpay Sandstone in the better-described sections north of Portree. Coarser sediment and the field setting favour the uppermost Scalpay interpretation, but the correlation is explicitly inconclusive. The local bed has no established thickness or bed number.
Portree Shale Formation
The Portree Shale Formation is Toarcian in age. Its regional definition is dominated by dark, locally laminated, organic-rich mudstone, but the local exposures are badly disturbed and do not provide a complete formation log.
Crushed Toarcian shale exposures. At Creagan na Sgalain, the Survey recorded 12 ft (about 3.7 m) of Upper Lias shale; about 400 yd north it recorded only 5 ft (about 1.5 m), described as badly crushed. Both sections lie within the Beinn Tianavaig landslip. These observations demonstrate a substantial, though incomplete, shale interval. They do not show that all Toarcian sediment here is only a few centimetres thick.
Limits of the local succession. The Raasay Ironstone Formation is a recognised unit in the wider east-Skye succession, but a separately measured ironstone bed has not been securely established for this exact shore section in the sources used here. The ammonite-rich limestone should not automatically be labelled Raasay Ironstone. The old Upper Lias measurements do not resolve all the modern formation boundaries within this disturbed interval.
Above the Lias Group. The Bearreraig Sandstone Formation is a stand-alone formation with no parent group. The following sandstone therefore belongs to a younger marine succession, rather than another subdivision of the Lias Group.
Bearreraig Sandstone Formation
The formation spans the latest Toarcian to Bajocian across its wider outcrop. Only a truncated basal remnant is documented beside the headland, and its precise local age remains unresolved. Older accounts describe these local rocks as Inferior Oolite.
Basal phosphatic horizon. At the southern end of the Beinn Tianavaig cliffs, Woodward described sandstone resting in an erosional hollow in the older Upper Lias shales. A dark-brown, nodular, ooidal and phosphatic layer lined the hollow and was only 2–3 in (about 5–8 cm) thick. Microscopic examination recorded shell and echinoderm fragments, foraminifera and ooids in a calcitic matrix. This is an erosional basal deposit beneath the younger sandstone, not a measure of the total Toarcian succession.
Dogger-bearing marine sandstone, about 15 ft (4.6 m) exposed. The section about 400 yd north of Creagan na Sgalain contains sandstone with calcareous doggers, belemnites and phosphatic nodules at its base. The higher Jurassic succession has been removed before deposition of the overlying Palaeocene beds. Its member and ammonite-zone assignments remain unresolved.
Jurassic–Palaeogene unconformity. The younger plant beds rest across an erosion surface on the truncated Jurassic sandstone. The Jurassic Great Estuarine succession present farther north is cut out here. Coal and plant-bearing shale in this local sequence belong to the much younger volcanic episode; they must not be treated as the Jurassic oil shale formerly proposed by Lee.
SKYE LAVA GROUP
The Palaeocene succession records the onset of volcanic activity and the accumulation of plant-bearing sediments before and during volcanism. Dolerite sills are later intrusions into the layered succession and must be distinguished from the deposited beds.
Portree Hyaloclastite Formation
This is the modern name for the Palagonitic Tuffs and Plant Beds of older accounts. At and just north of Creagan na Sgalain, the sedimentary part is particularly important. The Survey’s numbered plant-bed section is retained below, in ascending order; its original numbers refer to this local log, not to Jurassic ammonite beds.
Bed 1: greenish sandstone, 2 ft (about 0.6 m). This is the lowest plant-bed unit in the published section, directly above the Jurassic sandstone. Its position marks the younger sedimentary succession above the unconformity.
Bed 2: carbonaceous shale, 1 ft (about 0.3 m). A thin organic-rich shale succeeds the basal sandstone. A dolerite sill separates it from Bed 3 in the present exposure.
Lower dolerite sill, 20 ft (about 6.1 m). The intrusion lies between Beds 2 and 3. Its thickness is not part of the deposited sedimentary succession.
Bed 3: carbonaceous shale, 6 ft (about 1.8 m). A thicker carbonaceous shale interval occurs above the lower sill and below the finely flaggy beds. The published local log does not name plant species from it.
Bed 4: thin flaggy beds, 6 in (about 0.15 m) in total. The individual flaggy layers are approximately ¼ in (6 mm) thick. The thinness of each layer must not be confused with the thickness of the whole bed.
Bed 5: plant-bearing flaggy beds, 1 ft (about 0.3 m). Plant debris is specifically recorded from this horizon. It provides direct evidence that at least some of the plant-bearing rock on this shore is Palaeocene.
Bed 6: bedded sandstone, 20 ft (about 6.1 m). A substantial sandstone interval with thin shaly partings overlies the flaggy beds. A second dolerite sill lies between this sandstone and the uppermost carbonaceous bed.
Upper dolerite sill, 40 ft (about 12.2 m). This is the thickness assigned to the upper intrusion in the original printed section. It does not refer to the carbonaceous shale and coal above it.
Bed 7: carbonaceous shale and coal; thickness unspecified. The uppermost numbered sedimentary unit is followed by the palagonite tuffs. No numerical thickness is given for Bed 7 in the original section, so none is inferred here.
Overlying volcanic deposits. The local coast description records dark greenish ashy mudstones and coarse accumulations of basalt fragments, with a thin black shale near the base and plant-bearing shale, sandy mudstone and sandstone lenses. These belong to the early volcanic succession; no complete local tuff thickness is established by the measured plant-bed log.
Microscopic plant record. Two later samples of sandstone from the plant beds near Camas Tianavaig were studied for a report published in 2018. One yielded sparse fungal remains and pollen, including Alnipollenites verus, Inaperturopollenites hiatus and Triporopollenites mullensis. The assemblage was too sparse and the taxa too long-ranging to provide a precise age determination.
Beinn Edra Formation
The basaltic lava succession above the Portree Hyaloclastite Formation can be traced southwards from the Portree area to Tianavaig Bay and Ollach. These Palaeocene lavas form the higher volcanic framework of Beinn Tianavaig.
Later landsliding and modern shore deposits. Large-scale sliding has displaced both Jurassic strata and volcanic rocks around Beinn Tianavaig. It has crushed weak shale, obscured contacts and scattered large sandstone and igneous blocks across the shore. Scree, landslide debris and modern beach material are younger surface deposits, not additional members of the bedrock succession. A loose fossil-bearing block can therefore preserve a useful fossil assemblage without retaining a securely known stratigraphic position.
References
Anderson, F. W. and Dunham, K. C. (1966). The geology of Northern Skye. Geological Survey memoir, especially Chapters 2, 3 and 5; the original plant-bed section is on p. 75.
Woodward, H. B. (1901). Note on a phosphatic layer at the base of the Inferior Oolite in Skye. Geological Magazine, decade IV, 8, 519–520.
Morton, N. (2004). Prince Charles’ Cave to Holm, including the explicit comparisons with the Tianavaig outcrops. In British Lower Jurassic Stratigraphy, Geological Conservation Review Series 30. The northern measured log is not applied to this shore.
British Geological Survey. Lexicon entries for Scalpay Sandstone, Portree Shale, Bearreraig Sandstone, Portree Hyaloclastite and Beinn Edra formations.
Emeleus, C. H. and Bell, B. R. (2005). The Palaeogene volcanic districts of Scotland, fourth edition. British Regional Geology, section on the Skye Lava Group.
Árting, U., Condon, D., Riding, J. B. and Riishuus, M. S. (2018). Revised chronostratigraphy of the Faroe Islands Basalt Group and the British Palaeogene Igneous Province. BGS Commissioned Report CR/18/031, section 4.2.1 and Table A3.
SAFETY
This is a demanding, uneven coastal walk with narrow paths above steep slopes, loose boulders and slippery, seaweed-covered rock. It is unsuitable for young children or anyone uncomfortable on exposed ground. Keep clear of cliff faces and overhangs, avoid unstable blocks, and never climb the cliffs to look for fossils.
Plan the shore visit around a falling tide and leave enough time to retrace the beach before the water returns. Parts of the foreshore can be submerged at high tide; a falling tide does not make every section safe. Turn back if waves, a swollen burn, poor visibility or damaged ground obstruct the approach. Avoid the route in rough seas, strong winds or other conditions that make footing or escape uncertain.
EQUIPMENT
Wear sturdy walking boots with good grip and carry waterproofs, food, drinking water, a map and a means of checking tides. A hand lens, camera and small photographic scale are the most useful tools for examining shells and ammonites. Carry a charged phone, but do not rely on continuous reception along the cliffs.
Do not burden yourself with heavy tools or large blocks on this narrow, tiring route. Observation and photography are the appropriate starting point where collecting permission has not been established. If permission is granted for particular loose material, use only the methods and quantities agreed with the landowner; never work beneath unstable cliffs.
CLEANING AND TREATING
For specimens already lawfully collected, keep fragile shells and ammonites supported in their matrix. Begin with gentle dry brushing and examine the fossil under a hand lens before attempting to remove rock. The hard calcareous blocks may fracture through the fossil rather than around it, while shale can split or crumble unexpectedly.
Do not soak unknown shale specimens or use acids, bleach or varnish as a routine treatment. Avoid heat when drying damp material. Keep labels with the exact locality and, where known, the bed or rock type: the mixed shoreline material represents more than one geological age. Ask an experienced preparator before attempting work on a delicate or unusual fossil.
IDENTIFY YOUR FINDS
Need help identifying a fossil? Share clear photos, where you found it and its size with the community.
FURTHER READING
The geology of Northern Skye: Jurassic rocks
The geology of Northern Skye: plant beds and volcanic sediments
British Lower Jurassic Stratigraphy: east-Skye succession and Tianavaig comparisons
ACCESS RIGHTS
NatureScot boundary data checked on 15 October 2026 place the Tianavaig Bay starting area and the coastal walk described here outside mapped Sites of Special Scientific Interest (SSSIs) and outside the areas covered by the Skye Nature Conservation Order 2019. The Order protects specified sites elsewhere on Skye; it is not an island-wide collecting restriction.
Follow the Scottish Fossil Code. Walking access does not itself give permission to extract, collect or retain fossils. No site-specific collecting permission has been verified for this guide, so obtain permission from the appropriate owner before taking specimens. Until arrangements are clear, observe and photograph fossils in place. Leave bedrock intact, avoid destructive breaking of large blocks, and seek expert advice before attempting to remove an unusual or potentially important find.
Seasonal access restrictions associated with eagles were reported in the earlier guide for May–August, but their present dates and extent have not been independently confirmed. Check current notices and local advice before continuing along the coast. Golden and white-tailed eagles have legal protection: nesting birds and dependent young must not be intentionally or recklessly disturbed, harassment is prohibited throughout the year, and habitually used nests are protected even between breeding seasons. Do not approach nesting areas or interpret the absence of a sign, or a date outside May–August, as permission to disturb birds.
Follow the Scottish Outdoor Access Code’s wildlife guidance, keep dogs under close control and move away quietly if wildlife becomes alert or agitated. Observe any local requests to avoid a section of the shore, and turn back where a safe, non-disturbing passage is not possible.
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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