Lustrous ammonites, belemnites and shell-filled nodules make Flodigarry’s Jurassic shore a fascinating place to explore. On the northern side of Staffin Bay, fossil-rich mudrocks preserve the international reference point for the start of the Kimmeridgian. Their changing ammonite assemblages tell a remarkably detailed story across the Oxfordian–Kimmeridgian boundary.
FIND FREQUENCY: ♦♦♦ – Fossils can be visible in weathered mudrock and nodules; exposure varies with tides and shingle cover.
CHILDREN: ♦♦ – Better suited to older children under close supervision on the slippery, boulder-strewn shore.
ACCESS: uneven shore walk – A path reaches the coast, followed by rough intertidal ground.
TYPE: Wave-cut mudrock outcrops, nodules and loose blocks. Plan an observation and photography visit; collecting requires permission.
DIRECTIONS
♦ From Staffin, follow the A855 north towards Flodigarry and take the signed road into the township. The shore path starts in the village; the local community route describes limited parking near the red telephone box. Keep gates, driveways and passing places clear.
♦ Follow the established shore path, then explore the boulder-strewn coast only as tide and weather conditions allow. The community guide describes a return walk of about one mile. Allow extra time for the uneven ground and for looking at the rocks.
♦ The original shore reference is NG 46795 71540. The studied boundary sections lie nearby around NG 468 714; these are geological reference points, not parking coordinates or a promise of a visible marker. Check the local Flodigarry route information and signs before visiting.
FOSSIL HUNTING
Ammonites are the outstanding fossils of Flodigarry. Look closely at naturally exposed mudrock surfaces for coiled outlines and repeated ribs: many shells have been flattened during burial, but fine ornament can survive. Some retain a lustrous, mother-of-pearl surface that contrasts with the grey rock. A low, oblique light can make a faint impression easier to see. Photograph the fossil with a scale and a wider view of its position; thin shell films can be damaged by even gentle attempts to lift them.
The ammonites change through the succession rather than forming one interchangeable collection. Late Oxfordian beds contain Ringsteadia and Microbiplices. Near the top of Bed 35 these give way to the earliest Pictonia and associated Prorasenia, the change used to recognise the start of the Kimmeridgian. Higher beds contain further Pictonia assemblages and then Rasenia. The smaller ammonites historically grouped broadly with Amoeboceras include forms now treated as Plasmatites and Amoebites. Shape and ribbing can help compare specimens, but a flattened fragment or an old photograph is rarely enough for a secure species identification.
Belemnites offer a different kind of fossil to recognise. Their solid guards are commonly bullet-shaped or rod-like, with broken pieces sometimes showing a rounded cross-section. The published Kildorais account records them in Beds 37–43, especially near the top of Bed 43 and the bottom of Bed 45. That geological distribution is useful when studying an exposed section; a loose guard among beach stones cannot be assigned to a bed simply from where it lies.
Shell-packed nodules and blocks provide another rewarding subject for close inspection. Look at their naturally weathered faces for curved bivalve shells, shell fragments and small coiled gastropods. The locality literature records the bivalves Neocrassina ovata and Nuculana, and the gastropods Dicroloma and Procerithium, without assigning those particular records to individual beds here. Wood fragments are also recorded in the original field account. Treat isolated shapes cautiously: their texture and relationship to the surrounding sediment matter as much as a superficial resemblance.
For an observation visit, compare a few accessible outcrops with the loose rocks rather than trying to follow every numbered bed. Faulting and rotation repeat and displace the strata, while waves move material between exposures. The fine mudrocks also contain scientifically valuable dinoflagellate cysts and calcareous nannofossils, which require laboratory study rather than ordinary beach identification. Leave fossils and nodules in place unless the necessary collecting permissions have been obtained; the Access Rights section explains the site’s protection.
A chronological record of fossil research and the establishment of Flodigarry’s international Jurassic boundary reference.
1936–1937; published 1966 – Geological Survey framework
Survey work and writing by F. W. Anderson and K. C. Dunham established the northern Skye geological framework later published in their 1966 memoir. Its mapped Flodigarry shore sections became an important foundation for subsequent work on the faulted succession.
1968 – Ammonites and associated fossils studied
N. J. Morris’s thesis research documented Upper Jurassic fossils, including material from Flodigarry. The resulting records contributed to the locality’s ammonite and shelly-fauna evidence; this was a research collection, not the first discovery of fossils here.
1973 and 1989 – Fault blocks and ammonite succession resolved
J. K. Wright published stratigraphic work on the Staffin Shales and later refined the Early Kimmeridgian ammonite succession. Mapping and numbered beds provided a framework for comparing Flodigarry’s separate rotated exposures rather than treating the shore as a single uninterrupted section.
1995 – Field sections brought together
Nicol Morton and John D. Hudson’s field guide described the Jurassic rocks of Skye and Raasay, including the Staffin Bay exposures. Its treatment helped relate the Flodigarry wave-cut platform and marker beds to the wider succession.
2004–2006 – Detailed ammonite work and boundary proposal
A preliminary study was followed by the detailed Flodigarry ammonite account of Bronisław A. Matyja, Andrzej Wierzbowski and John K. Wright. Their 2006 publication named Pictonia flodigarriensis and strengthened the case for placing the international Oxfordian–Kimmeridgian boundary in this succession.
2007 – Radiometric age investigated
David Selby published a rhenium–osmium age study tied to the Staffin Bay boundary succession. Its estimate of 154.1 ± 2.2 million years was an independent dating result, rather than the definition of the boundary itself.
2009–2010 – Isotopes and magnetic polarity add correlation tools
Published studies of Staffin Bay belemnite and bulk-carbon isotopes, together with magnetostratigraphic work across the boundary, added evidence beyond ammonites. These approaches helped compare the Flodigarry succession with Jurassic sections elsewhere.
2012 – Organic matter preservation assessed
Lefort and colleagues published an organic-geochemical study of the proposed boundary stratotype. The exceptionally well-preserved organic matter and low thermal alteration supported the section’s value for investigating the Late Jurassic environment.
2016–2018 – International correlations refined
Further work clarified how the Flodigarry ammonite succession correlates between faunal provinces. Detailed ammonite, dinoflagellate-cyst and calcareous-nannofossil studies strengthened the evidence used in the final boundary proposal.
2019 – Jurassic subcommission approval
The International Subcommission on Jurassic Stratigraphy approved the Flodigarry proposal, advancing it towards formal international adoption.
2021 – Boundary formally ratified
Following approval by the International Commission on Stratigraphy, the International Union of Geological Sciences ratified the Flodigarry Global Stratotype Section and Point for the base of the Kimmeridgian. The defined point lies within Bed 35, below the conspicuous Bed 36 limestone marker.
2023 – Ratified reference section published
The full synthesis of the ratified boundary was published, bringing together the geological setting, ammonites, microfossils, geochemistry and magnetic-polarity evidence. This was the publication of the adopted standard, not a new ratification or a verified installation ceremony.
GEOLOGY
The fossiliferous rocks belong to the Flodigarry Shale Member of the Staffin Shale Formation. They accumulated during the Late Jurassic on an open marine continental shelf below storm-wave base, rather than on beaches or barrier islands. Fine clay and silt settled around shells and other organic remains; later carbonate growth produced thin limestone and nodule horizons that now help geologists match separated exposures.
The contrast between soft mudrocks and harder marker beds is particularly useful here. Waves strip and redistribute pebbles and boulders across the platform, revealing different patches of bedrock at different times. The ammonites are commonly compressed, yet some preserve delicate ribs and original nacreous shell. Their rapid changes through successive beds allow much finer correlation than the broad formation name alone.
Flodigarry is internationally important because the Oxfordian–Kimmeridgian transition is preserved within a detailed fossil succession. The ratified Global Stratotype Section and Point, or GSSP, fixes the start of the Kimmeridgian at a point 1.25 ± 0.01 m below the base of Bed 36, in the upper part of Bed 35. The limestone of Bed 36 is a convenient marker above it, not the boundary itself. The change from the last Ringsteadia to the earliest Pictonia provides the closely sampled ammonite evidence.
The rocks no longer lie as a simple horizontal stack. Ancient landslip movement produced rotated, fault-bounded blocks, with bedding locally dipping about 60–80°. The studied succession of roughly 35 m combines exposures in blocks F6 and F5; it is not a continuous cliff of that height or an easy uninterrupted walking traverse. Younger dolerite sills and dykes cut the Jurassic rocks, but the primary study describes thermal alteration only very close to their margins, rather than widespread baking of the fossil beds.
The two complementary chart panels show the upper and lower parts of this scientific composite, youngest first. Row heights are for readability and do not represent actual thickness. The complete bed descriptions below distinguish measured intervals from entire beds and explain the boundary evidence.
Detailed Flodigarry stratigraphy, from Bed 33 to Bed 45, with the ratified boundary and scientific references.
The following description runs from oldest to youngest. Thicknesses follow the modern measured intervals in the 2023 supplementary Appendix 2; lithological descriptions also draw on the older Kildorais account. Older published thicknesses sometimes differ and are not substituted into this modern series. The composite uses F6N/F6S through Bed 39 and the neighbouring F5 exposure for the younger beds; overlapping Bed 39 helps connect the sections.
Staffin Shale Formation
BGS does not assign this formation to a parent group. Its regional Callovian–Kimmeridgian age range and composite Staffin Bay thickness of at least 116.8 m describe the wider formation, not the amount exposed at the Flodigarry boundary sections.
Flodigarry Shale Member
The member consists mainly of dark- to medium-grey claystone and silty claystone, with occasional thin limestone, siltstone and fine sandstone markers. The modern synthesis describes about 60 m for the member, whereas the boundary study examines a roughly 35 m composite interval within it. The regional lower contact with the Digg Siltstone Member and the overlying volcanic deposits should not be read as two contacts demonstrated in this particular boundary log.
Bed 33 — upper 9.5 m studied
Grey silty mudrock forms the lowest part of the studied composite. Late Oxfordian assemblages include Ringsteadia, Microbiplices and Amoeboceras; changes within these groups subdivide the older ammonite succession. The 9.5 m is the upper interval examined, not the whole thickness of Bed 33.
Bed 34 — 0.20 m
An impersistent horizon of calcareous concretions makes a useful lower marker within the Oxfordian succession. It separates the underlying silty mudrock from the thicker mudrock of Bed 35, but does not mark the stage boundary.
Bed 35 — 6.0 m
Medium- to dark-grey, slightly bituminous silty mudrock spans the Oxfordian–Kimmeridgian boundary. Lower assemblages of Ringsteadia and Microbiplices are succeeded near the top by Pictonia and Prorasenia; Amoeboceras and Plasmatites provide a second, overlapping ammonite sequence. The formal boundary falls within this bed, not at a conspicuous change of rock type.
Bed 36 — 0.07–0.35 m
Limestone nodules or a thin limestone band form a prominent datum above the boundary. Its varying thickness is retained rather than reduced to a single convenient number. Measurements locating the GSSP are taken downwards from the base of this bed.
Bed 37 — 4.17 m
Grey silty clay overlies the limestone marker. The lowest part retains Pictonia flodigarriensis; higher levels contain Pictonia densicostata, with Plasmatites in the accompanying assemblages. The changing fauna subdivides the earliest Kimmeridgian succession without requiring a separate formal member.
Bed 38 — 0.28 m
Dark shaly clay contains abundant pale, flattened ammonites, including Pictonia densicostata. This fossil-rich interval is a useful marker within the early Kimmeridgian beds. The modern measured thickness is 0.28 m; the older Kildorais account gave 0.65 m and belongs to a different published measurement set.
Bed 39 — 1.92 m
Grey silty clay carries the succession from the upper Densicostata context towards the Normandiana assemblages. It forms the overlap between the F6 and F5 parts of the composite. The modern 1.92 m measurement differs from the older account’s 0.85 m; the two are not interchangeable.
Bed 40 — 0.15–0.45 m
A conspicuous limestone or nodule band is a second strong marker in the younger part of the composite. It helps identify the succession in the separate fault block; its presence does not demonstrate an unbroken shore traverse from Bed 36.
Bed 41 — 1.52 m
Pale silty clay contains ammonites of the Pictonia normandiana/Pictonia baylei group, Prorasenia hardyi and Plasmatites. The accompanying cardioceratid succession passes into Amoebites, adding another means of correlation.
Bed 42 — 0.40 m
Darker silty clay contains the Amoebites bayi/Amoebites cricki assemblage. Lustrous shell preservation was noted in the historical description. This narrow interval should be distinguished from the paler beds above and below it.
Bed 43 — 4.39 m
Paler clay contains later Pictonia and Prorasenia in its lower part, while Rasenia inconstans occurs higher in the bed and indicates the younger Cymodoce context. Belemnites are recorded particularly near its top. The whole bed should not be labelled as a single undifferentiated ammonite horizon.
Bed 44 — 0.17 m
A resistant argillaceous sandstone forms a thin marker within the younger succession, with Rasenia inconstans. The modern measurement is 0.17 m; the older lithological account described approximately 0.15 m.
Bed 45 — 1.6 m interval studied
Dark clay above the sandstone contains Rasenia and Amoebites subkitchini. Belemnites were noted particularly near the bottom. Only 1.6 m is represented by the modern sampled interval; an older account described exposure extending to 9 m, so 1.6 m must not be presented as the total exposed thickness of Bed 45.
The ratified boundary within Bed 35
The point is 1.25 ± 0.01 m below the base of Bed 36. The last sampled Ringsteadia at 1.26 m and earliest Pictonia at 1.24 m below that datum bracket it. The recorded Pictonia flodigarriensis specimen at 1.08 m is younger and must not be substituted for the boundary position. The base of the Subboreal Baylei Zone, Densicostata Subzone and flodigarriensis horizon corresponds to the base of the Boreal Bauhini Zone. Zone, subzone and horizon are different ranks, not interchangeable labels.
The current international register calibrates the base of the Kimmeridgian at 154.8 ± 0.8 million years. That numerical estimate is distinct from the fixed physical definition and from Selby’s 2007 rhenium–osmium result of 154.1 ± 2.2 million years. Improvements to age calibration do not move the defined point in the rock.
Depositional and structural interpretation
These fine sediments accumulated offshore below storm-wave base. Carbonate nodules formed within the sediment, while the fossil succession records changes through time in connected marine faunas. Ancient landslip movement later faulted and rotated the beds; Paleocene dolerite intrusions caused very local alteration at their edges. The mapped sections and marker horizons are essential for correlating the tilted blocks, and beach cobbles do not preserve their original stratigraphic order.
References
Wierzbowski, A. and colleagues, 2023. The Global Stratotype Section and Point for the base of the Kimmeridgian Stage at Flodigarry, Staffin Bay, Isle of Skye, Scotland. Episodes 46, 281–307; figures 1–3 and supplementary Appendices 1–2. DOI: 10.18814/epiiugs/2022/022046.
Matyja, B. A., Wierzbowski, A. and Wright, J. K., 2006. The Sub-Boreal/Boreal ammonite succession at the Oxfordian/Kimmeridgian boundary at Flodigarry, Staffin Bay. Transactions of the Royal Society of Edinburgh: Earth Sciences 96, 387–405.
Cox, B. M., 2001. Kildorais, Staffin Bay. In British Upper Jurassic Stratigraphy, Geological Conservation Review Series 21.
BGS Lexicon: Staffin Shale Formation and Flodigarry Shale Member.
International Commission on Stratigraphy: current GSSP register.
SAFETY
Wet clay, algae and loose boulders make this a slippery and tiring shore. Wear footwear with good grip, take small steps and avoid unstable blocks or steep slopes. Keep children close, and do not climb the tilted exposures or dig beneath the cliff to find a particular bed.
Check local tide times and the forecast, and visit in calm conditions with enough time to return comfortably. Waves can reach exposed rocks even before high tide; do not rely on the old assurance that you cannot be cut off. Keep the route back in sight and turn around before conditions deteriorate. Tell someone your plans and do not rely on mobile reception.
EQUIPMENT
A camera, scale, hand lens and notebook are the most useful tools for an observation visit. Take a map, tide information, waterproof clothing and sturdy footwear. Photographs showing a fossil, its surrounding rock and its wider position are more informative than an isolated close-up. Do not bring extraction tools on the assumption that loose fossils or nodules may be taken without permission.
CLEANING AND TREATING
For specimens already lawfully collected, retain every locality and bed record and support fragile pieces in a rigid box. Thin ammonite shell films and their muddy matrix can flake or split; avoid scrubbing, soaking or forcing the layers apart. A soft dry brush may be sufficient for stable loose dirt, but stop if the surface begins to lift.
Do not apply household acids, bleach or routine varnish. Pyritic or iridescent material can require specialist conservation, and an important ammonite may lose scientific information through unnecessary preparation. Photograph the specimen before any work and seek advice before consolidating unstable shell or removing attached matrix.
IDENTIFY YOUR FINDS
Need help identifying a fossil? Share clear photos, where you found it and its size with the community.
FURTHER READING
Deposits: Staffin Dinosaur Museum and the regional fossil collections
Flodigarry: the ratified Kimmeridgian boundary study (2023)
Boundary study: supplementary history and measured fossil records
Geological Conservation Review: historical Kildorais account
BGS Lexicon: Flodigarry Shale Member
BGS Lexicon: Staffin Shale Formation
International Commission on Stratigraphy: GSSP register
Skye Ecomuseum: Flodigarry shore walk
ACCESS RIGHTS
The studied Flodigarry boundary shoreline is within Trotternish Ridge Site of Special Scientific Interest. Obtain the landowner’s permission before collecting, and ensure that any proposed sampling or removal has the appropriate NatureScot consent under the SSSI arrangements. Permission for ordinary walking does not give permission to remove fossils, including loose specimens or nodules. Until those permissions are in place, leave the material where it is and enjoy the site through observation and photography.
The site’s listed operations include removal of fossils and geological specimens. NatureScot’s current guidance on geological sampling in Scottish SSSIs explains the separate landowner and protected-site requirements. Scientific research access reported in publications is not a general collecting permit for visitors.
Some other parts of Skye’s coastline have additional protection under the Skye Nature Conservation Order 2019. Its mapped areas do not automatically cover every fossil locality on the island; this northern Flodigarry shoreline is not one of the areas identified on those plans. The SSSI protection described above remains relevant. Read NatureScot’s Skye fossil heritage guidance before exploring elsewhere.
Follow the Scottish Fossil Code, current signs and local instructions. If you see an unusual or potentially important fossil, record its position and photograph it in place rather than attempting to extract it.
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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