At Tarbat Ness, Devonian sandstone ledges near the lighthouse have yielded small fish remains, chiefly scales and occasional larger fragments. The exposed rocky shore also offers striking cross-bedding and pebbly river deposits, but access is difficult and collecting requires permission.
FIND FREQUENCY: ♦♦♦ – Fish remains are uncommon and usually fragmentary; this is not a reliable place to find complete fish.
CHILDREN: ♦♦♦ – The steep shore access, slippery ledges and exposed coast make the fossil locality unsuitable for a family collecting outing.
ACCESS: ♦♦ – Parking is near the lighthouse; the historic descent to the shore is steep and slippery and its present condition needs checking.
TYPE: Devonian cliffs and rocky foreshore, with pebbly sandstone ledges. The nearby shore is protected as a Site of Special Scientific Interest.
DIRECTIONS
♦ Follow the road towards Tarbat Ness lighthouse from the B9165 approach. The final narrow road leads to the car park southwest of the lighthouse; check signs at the car park for the current arrangements.
♦ Parking/approach reference: 57.86286°N, 3.77884°W. This is an access reference near the car park, not a fossil-bed or shore-descent waypoint.
♦ The fossil locality described here is the east/southeast headland shore near the car park and south of the lighthouse. The original route descended from the back of the car park by a steep, slippery cliff path. Do not attempt this descent without first checking that it is currently usable and that a safe return is possible.
♦ Do not assume that the path towards the point provides access to these shore ledges. Keep to a safe viewpoint if shore access is doubtful.
FOSSIL HUNTING
The original field account records small fish scales in pebbly ledges near the lighthouse car park, south of the point, with larger fish fragments found less often. It distinguishes a red pebble-rich bed, in which the reported scales looked pink, from a cream-coloured pebble-rich bed containing white remains. These are useful descriptions of the material previously observed, rather than formally named fish beds. Their exact position within the local succession has not been established, and no fish species can be assigned confidently to these photographed ledges.
Where safe access and the relevant permission have been confirmed, start with close observation of naturally exposed surfaces. A hand lens and clear photographs are more useful than searching for large, complete specimens. Look at the fine material between the rounded pebbles as well as the bedding surfaces, remembering that a pale or pink patch alone is not enough to identify a scale. Record the shape, texture and position of any possible remains, and photograph them both close up with a scale and in their surrounding rock. Do not prise material out of a ledge to test an identification.
The sandstone contains many features that are geological rather than fossil remains. Rounded quartz pebbles, mineral patches, curved sedimentary layers and weathered hollows can all draw attention. Cross-bedding is particularly conspicuous: inclined bands inside a larger bed record the movement of sand before it became rock. Convoluted layers and small sand-volcano structures nearby formed as wet sediment slumped or expelled water. Recognising these structures helps avoid mistaking every unusual marking for a fossil.
Tarbat Ness also has a wider scientific reputation for fish-bearing concretions and ancient animal tracks, but those records come from different parts of the coastal succession. The Middle Devonian fish-concretion beds lie farther south, while the probable tetrapod tracks and many arthropod traces are associated with the Gaza Formation towards Castlehaven on the northwestern side. They should not be expected in the red and cream ledges beside the lighthouse merely because all are described under Tarbat Ness.
Obtain the landowner or relevant rights-holder’s permission and check the protected-site requirements before removing any material. Leave a potentially important find in place, record it carefully and seek specialist advice. Do not climb onto high ledges or loosen the softer rock with a trowel: observing accessible surfaces is the appropriate starting point at this protected exposure.
Significant geological research and conservation milestones at Tarbat Ness, with wider coastal discoveries distinguished from the lighthouse ledges.
1973 – First statutory site notification
Tarbat Ness was first notified as a Site of Special Scientific Interest, recognising the value of this coastal area. The designation encompasses a wider stretch of shore than the lighthouse collecting ledges.
1977 – Devonian groups and their boundary interpreted
Armstrong’s geological framework distinguished the Middle Devonian Strath Rory Group from the Upper Devonian Balnagown Group. At the southern part of the Tarbat Ness section, a faulted boundary allowed for an unconformity farther inland, an interpretation later reassessed through detailed work on the coastal fault blocks.
22 August 1985 – SSSI renotification
The site was renotified under the Wildlife and Countryside Act 1981. Today its protected interests include non-marine Devonian geology, coastal erosion features and maritime cliff habitat.
1987 – Detailed local stratigraphy and sedimentary environments
Rogers developed an informal subdivision of the succession, including the Tarbat Ness and Gaza formations. The work described river deposits around the lighthouse, dune and sabkha environments farther west, and a reconstructed conformable transition between the Middle and Upper Devonian rocks around Port Tarsuinn.
1990 – Probable tetrapod tracks published
Rogers published an interpretation of probable tetrapod footprints from the wider Tarbat Ness coastal section. The track-bearing setting is associated with the Castlehaven side of the headland, rather than the fish-bearing pebble ledges described beside the lighthouse car park.
1996 – River, dune and sabkha environments linked
Marshall and colleagues incorporated the local sedimentological work into a wider reconstruction of the Orcadian Basin. Tarbat Ness helped show how river-dominated deposits could pass into sandy sabkha flats and migrating dunes.
2005 – Coastal succession synthesised
A detailed geological account brought together the mapped units, sedimentary structures and competing boundary interpretations. It emphasised the scientific importance of the whole Tarbat Ness section while distinguishing the river sandstones at the headland from the older strata to the south and the younger dune and sabkha deposits to the west.
2 November 2007 – Protected-site documentation reviewed
The statutory notification was reviewed under the Nature Conservation (Scotland) Act 2004. The accompanying site documentation described the geological exposures, coastal landforms and maritime habitat, with the council car park adjacent to the protected shore.
2011 – Port Tarsuinn studied in relation to the Taghanic Crisis
Marshall, Brown and Astin examined evidence from Port Tarsuinn in a study of Devonian environmental change and land–sea interactions. This concerns the southern part of the wider succession, not a newly identified fish bed at the lighthouse ledges.
2018–2019 – Trackway evidence reconsidered
Ahlberg’s study, published online in 2018 and in its journal volume in 2019, revisited the probable tetrapod tracks. The Tarbat Ness evidence was interpreted as quadrupedal walking on moist sandy surfaces in an inland, semi-arid setting, probably during the Frasnian. The tracks do not identify a particular body-fossil species at the lighthouse.
GEOLOGY
Tarbat Ness projects northeast between the Dornoch and Moray firths. Around the lighthouse, the coastal rocks are most plausibly assigned to the informal Tarbat Ness Formation within the Upper Devonian Balnagown Group. They preserve the deposits of a large river system near the margin of the Orcadian Basin. Thick sandstone beds, pebble-rich lenses and inclined cross-bedding record moving sand and gravel; many beds immediately around the lighthouse are almost or entirely free of pebbles.
The variation matters when looking at the shore. A pebbly lens is not necessarily a laterally continuous bed, and the proportion of pebbles changes through the succession and around the headland. Rounded, chiefly quartzose pebbles occur in small conglomeratic bodies, along bedding surfaces and within cross-sets. Elsewhere the sandstone is strongly contorted. Slumping, convoluted bedding and sand volcanoes indicate deformation while the sediment was still wet, with water escaping during rapid burial, probably in a braided river system.
The much broader geological section extends south to Middle Devonian rocks and west into younger Upper Devonian facies. Farther south, the Strath Rory Group includes river sandstones and thin calcareous mudstones with fish-bearing concretions, interpreted as intermittent lake deposits. Around Port Tarsuinn the relationship between these older beds and the Balnagown Group has been debated: a regional unconformity and faulted contact have been proposed, while a locally conformable succession has also been reconstructed from coastal fault blocks. Neither interpretation provides a measured position for the fish-bearing ledges in this guide.
West of the headland, the Tarbat Ness Formation passes upwards into the informal Gaza Formation. Thinner, finer sandstone and mudstone, ripples, desiccation features, traces of evaporite growth and wind-blown dune deposits record a change towards sandy sabkha flats and dunes, intermittently wetted by rainfall or flooding. Animal tracks survive on some of these surfaces near Castlehaven. This is a distinct setting from the pebbly river sandstones at the lighthouse.
Across the entire geological conservation site the beds dip northwest, from about 10° to nearly 40°, on the southeastern limb of the Black Isle Syncline. Faults interrupt the succession, whose published composite totals about 800 m. That figure describes the wider coastal section, not the height of the cliffs or the thickness of a single formation at the collecting ledges. Today, wave undercutting, pebble abrasion and chemical and biological weathering shape the tilted sandstone into the ledges, hollows and small cliffs seen around the shore.
Detailed geology of the lighthouse sector and the separate older and younger parts of the Tarbat Ness coastal succession.
Scope and nomenclature. The lighthouse sector is described first. The southern and northwestern exposures are included afterwards as clearly separate context, because the complete Tarbat Ness scientific section crosses several units and fault blocks. Tarbat Ness Formation, Gaza Formation and the Rockfield Formation–Port Tarsuinn Member subdivision are Rogers’s informal local terminology. They should not be read as a precisely measured succession at the fish ledges.
BALNAGOWN GROUP
The Upper Devonian Balnagown Group forms the headland and continues along its northern coast. Its lower river-dominated deposits are represented by the informal Tarbat Ness Formation; higher strata comprise the Gaza Formation’s fluvial, wind-blown and sabkha facies. The wider Upper Devonian succession is broadly placed in the Frasnian–Famennian interval, but this does not establish a stage or exact horizon for the fish fragments reported near the car park. No verified total formation thickness is available for those ledges.
Tarbat Ness Formation — informal; lighthouse and headland sector
Pebbly sandstone and conglomeratic lenses. Red sandstone with conglomeratic lenses and thin conglomerate interbeds characterises the lower Balnagown Group, exposed northwards from Port Tarsuinn and around the headland. The pebbles are well rounded and chiefly quartzose. Individual conglomeratic beds reach about 20 cm, but lenticular bodies and isolated clasts are more common. Pebbles may be scattered along bedding surfaces or line the inclined foresets of large cross-sets. The 20 cm figure applies to individual conglomeratic beds in the published formation description, not to a named fish bed at the car park.
Lighthouse sandstone interval. Pebble concentration decreases up the succession towards the point. Around the lighthouse and headland, many thick red sandstone beds contain only scattered pebbles or none at all. Large-scale, commonly tabular cross-bedding is conspicuous. Convoluted lamination, slumped bedding and sand volcanoes record disturbance and escape of pore water before full consolidation. These structures are interpreted as dewatering during rapid burial of water-saturated sand, probably in a large braided river system; they are not fossil bodies or a separate formal member.
Red and cream pebble-rich ledges. The original collecting account distinguishes these two colour varieties near the car park and reports small scales and rarer larger fish fragments. The surviving photographs show the pebbly rock context, but do not establish a taxonomic identification or a secure bed-by-bed correlation. No thickness, formal bed name or direct equivalence to the older Strath Rory fish-concretion horizons is assigned here. Colour alone cannot identify a formation or a fish scale.
Upper formation towards Port Albion and Canas Solais. West of the headland, the proportion of pebbles increases irregularly again through the thick cross-bedded red sandstones. It then falls abruptly, together with bed thickness, at the transition into the Gaza Formation.
Gaza Formation — informal; separate northwestern coastal context
Thin sandstone and mudstone facies. Above the pebbly Tarbat Ness Formation lie very thinly bedded, fine-grained, clay-rich sandstones with rare mudstones. Red and yellow-green colours commonly produce mottled beds. Wavy lamination is picked out by colour variation or silty partings, and some bedding surfaces carry low-amplitude ripples. Red mudstone flakes occur on bedding planes and as isolated clasts in sporadic thicker sandstone beds. These thicker sandstones may be river-laid or wind-blown.
Sabkha surfaces and intermittent wetting. Desiccated mud layers were broken into flakes and incorporated into sand. Small adhesion warts, approximately 0.5–3 mm across, are interpreted as grain clusters held together by moisture on otherwise dry sand. Rare rain-impact pits also occur. Rippled surfaces may reflect wind-blown sand adhering to damp patches or sheet flooding, possibly accentuated by wind scour. Polygonal to irregularly sinuous ridges rise up to about 1 cm above some surfaces and disturb underlying laminae; they have been interpreted as buckling caused by expansion during evaporite formation. These are surface structures and process indicators, not measurements of fossil size or formation thickness.
Castlehaven compound dune bodies. Towards the northwestern end of the wider site, the higher Gaza Formation includes compound aeolian dunes, or draas. Sandstone bodies reach up to 14 m thick and contain large cross-bedding with three orders of bounding surface. Reconstructions from set and coset geometry suggested dune heights up to about 6 m and interdune distances up to about 80 m. The latter two figures describe reconstructed dune form and spacing, not measured stratigraphic thicknesses.
Tracks, burrows and bioturbation. The Gaza Formation, especially near Castlehaven, contains arthropod tracks and burrows, locally homogenised sediment produced by animal activity, and probable tetrapod tracks. Many tracks occur in dune sandstone on surfaces with adhesion warts. The trace fossils alone do not tightly date the whole formation. A later reassessment favoured a probably Frasnian age for the tetrapod-track setting and interpreted quadrupedal, lateral-sequence walking on moist inland sandy surfaces. This is evidence of animal behaviour in a semi-arid dune–sabkha landscape, not a record of amphibian body fossils at the lighthouse ledges.
STRATH RORY GROUP — SEPARATE SOUTHERN COASTAL CONTEXT
Upper-group river sandstone and calcareous mudstone. Older rocks crop out along the east coast from roughly 1.5 km south of the point and continue southwards. Thick yellow and red fluvial sandstones contain fairly common thin calcareous mudstone interbeds. The sandstones are cross-bedded on a large scale and their internal lamination is locally strongly convoluted. Sporadic carbonate concretions in the mudstone have yielded fish fragments supporting an early Givetian age. Although the group extends down into the Eifelian elsewhere, that broader range should not replace the more specific evidence for this part of the coast. The 1.5 km figure is a position along the coast, not a unit thickness.
The calcareous mudstone laminae and concretions are interpreted as intermittent lake deposits between river sands, reflecting temporary expansion of the Orcadian Basin lake towards Easter Ross. Regional uplift and basin rejuvenation supplied the river systems. Thick conglomerates lower in the Strath Rory Group record sources to the west and south, but those lower conglomerates are not represented in this GCR section and should not be added to a local measured log.
Rockfield Formation — informal; Port Tarsuinn context
Port Tarsuinn Member — informal
At the top of the Strath Rory Group, Rogers identified a thick sandstone body of probable aeolian origin and called it the Port Tarsuinn Member of his informal Rockfield Formation. It represents a period of exposed, wind-worked sand before the coarse pebbly river deposits of the Balnagown Group. No dependable numerical thickness or finer bed subdivision is assigned from the published site synthesis.
Middle–Upper Devonian relationship. Armstrong placed the top of the Strath Rory Group at a fault south of Port Tarsuinn, probably the South Wilkhaven Fault recognised by Rogers. That interpretation permits an unexposed unconformity farther inland. Rogers instead reconstructed a complete, locally conformable passage through several fault blocks around Port Tarsuinn, with the probable aeolian sandstone overlain by coarse pebbly Balnagown strata. The wider regional unconformity and the proposed local conformity must remain distinct; a single continuous exposed boundary is not established for the lighthouse shore.
Structure and modern coastal form. The approximately 800 m published total combines parts of both groups over the wider, fault-disrupted site. Northwest dips increase from about 10° to nearly 40° on the southeastern limb of the Black Isle Syncline. Modern processes act unevenly on these tilted rocks: cliff undercutting is especially evident on the southeastern side, while abrasion by moving pebbles is important to the north and west. Saltwater weathering and biological activity contribute to pitting and hollows.
References
Stone, P. (2005), “Tarbat Ness, Ross and Cromarty”, in Barclay and colleagues, The Old Red Sandstone of Great Britain, Geological Conservation Review Series 31, pp. 96–102. Original chapter.
Ahlberg, P. E. (2019; online 2018), “Follow the footprints and mind the gaps: a new look at the origin of tetrapods”, Earth and Environmental Science Transactions of the Royal Society of Edinburgh, 109, 115–137. Article.
NatureScot, Tarbat Ness SSSI citation and site management statement, reviewed 2 November 2007. Site documents.
SAFETY
This is an exposed, rocky coast with difficult shore access. The historic cliff path was steep and slippery, and its current line and condition have not been verified. Do not descend where footing or the return route is uncertain, and do not climb high ledges to reach a possible fossil. Undercut rock, loose material and wet or algae-covered sandstone add to the risk.
Check the tide times and weather before visiting. The sea reaches the cliff foot and can cut off the shore route; allow a generous margin for returning before the tide rises. Swell and breaking waves can make low ledges unsafe even at low tide. Avoid rough conditions, stay away from cliff edges and wave-washed platforms, and tell someone your plans.
EQUIPMENT
Take sturdy footwear with a good grip, waterproof and windproof clothing, tide information and a charged phone. A hand lens, camera, small scale and notebook are useful for recording possible fish remains and sedimentary structures. Pack any material only after removal has been authorised, using soft wrapping and a rigid box to support fragile surfaces. Do not bring a trowel, hammer or chisel for working the protected ledges without the specific permissions and consents for that activity.
CLEANING AND TREATING
For a specimen collected with permission, keep its locality photographs and label with it. Small scales and fragmentary remains may be difficult to distinguish from the surrounding grains, so examine the surface under magnification before doing any cleaning. Let damp material dry slowly at room temperature, then remove only loose dust with a soft dry brush. Stop if grains or fossil material lift away.
Avoid soaking crumbly sandstone, scraping out pale patches, applying acids or bleach, or coating the surface with varnish. Aggressive preparation can remove both a tiny fossil and the sedimentary context needed to identify it. Leave an unusual or potentially important specimen unprepared and obtain specialist advice before attempting consolidation or further work.
IDENTIFY YOUR FINDS
Need help identifying a fossil? Share clear photos, where you found it and its size with the community.
FURTHER READING
Deposits Magazine: Fossil fishes of the Old Red Sandstone, Scotland — regional background
Geological Conservation Review: Tarbat Ness coastal succession
Follow the footprints and mind the gaps — Devonian trackway research
NatureScot: Tarbat Ness SSSI and official documents
ACCESS RIGHTS
The coastal exposures form part of Tarbat Ness Site of Special Scientific Interest, protected for non-marine Devonian geology, coastal geomorphology and maritime cliff habitat. The car park lies adjacent to the designated shore. Access to a path or viewpoint does not itself grant permission to remove fossils or disturb the rock.
Arrange collecting permission before removing any material. Ask the landowner or relevant rights-holder and check the site-specific arrangements with NatureScot before collecting. The site’s consent list includes modification of natural features and clearance of boulders, loose rock or scree. Do not assume that loose material can be removed freely, or that designation alone creates an identical blanket collecting rule at every SSSI. Leave the protected exposures undisturbed unless the relevant permission and any necessary consent are in place.
Follow the Scottish Fossil Code: seek permission, collect responsibly, record where specimens came from and report significant finds. Respect the site’s wildlife and maritime vegetation as well as its geology.
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