Barns Ness Fossil Hunting

1854–1860 – The coast mapped by the Geological Survey
The coastal limestones at Catcraig were mapped in detail during the first Geological Survey work in Scotland. The mapping began under A.C. Ramsay in 1854, and the geological sheet covering the district was completed and published in 1860.

1866 – Limestone succession and fossils documented
The first Geological Survey memoir of East Lothian described the limestone succession and faults at Catcraig and listed fossils from the locality. It established an early published framework for interpreting the fossil-rich coast.

1881 – Catcraig specimens help establish a crinoid genus
P. Herbert Carpenter and R. Etheridge, Jun., described and figured small crinoid cups recovered from Catcraig shore shales in their original study of Allagecrinus. The Catcraig examples, assigned to Allagecrinus austinii, formed part of the material used to investigate the structure and growth of these minute crinoids.

1902–1910 – The coastal geology resurveyed
A Geological Survey resurvey in 1902–1904 was followed by the revised East Lothian memoir in 1910. The new account refined the coastal limestone succession and illustrated the distinctive coral-bearing and potholed limestone exposures at Catcraig.

1910 – Catcraig corals contribute to an evolutionary study
R.G. Carruthers used corals from the shales at Catcraig in an influential study of changes in the Zaphrentis delanouei group through the Scottish Lower Carboniferous. The work used serial sections through the corals to compare their internal structure and growth.

1921 – Catcraig limeworking closes
The limekilns associated with the extensive coastal limestone quarries closed in 1921. The surviving workings preserve an important part of the history of the limestone exposures visitors explore today.

1952 – The coast first notified as an SSSI
Barns Ness Coast was first notified as a Site of Special Scientific Interest. Its fossil-rich Carboniferous succession is important for linking the geology of Scotland with that of northern England.

1960 – Coast transferred to the county council
The local historical account records that the new cement-company owners transferred coastline at Barns Ness and White Sands to the county council in 1960. This forms part of the history of public enjoyment and interpretation of the shore.

1966 – Historic limekilns restored
The Catcraig limekilns were restored by the county council, conserving structures closely associated with the quarrying of the fossil-bearing coastal limestones.

By 1969 – A marked geological trail in place
A geological map displayed at the Catcraig limekiln and markers along the shore were already helping visitors identify the limestone and coal succession. This established the coast as an interpreted geological walk as well as a research locality.

1969 – Two new fossil megaspores described
Edwin Spinner’s study of two thin coal seams on the shore between Catcraig and the lighthouse described the new megaspore species Setosisporites pseudoreticulatus and Zonalesporites fusinatus. He also revised the classification of several other megaspores and compared the assemblages with records from Europe and North America.

1973 – Marine communities studied quantitatively
M.A. Whyte’s detailed sampling at Catcraig formed part of a study comparing the fossil communities in the upper Viséan marine beds around Dunbar. The research used the abundance and distribution of fossils to reconstruct conditions on the ancient sea floor.

1973 – Miospores used to correlate the shore sequence
Palynological work used microscopic plant spores to correlate the Carboniferous succession. In the Catcraig–Barns Ness section, a boundary between two miospore zones was placed in the mudrocks above the Skateraw Middle Limestone.

1975 – A named megaspore reinterpreted
Jadwiga Karczewska concluded that the megaspore named Zonalesporites fusinatus from the Barns Ness coast in 1969 was the same species as the earlier-named Zonalesporites mucronatus. This revised the interpretation of one of the site’s formally described fossil forms.

1984 – SSSI protection renewed
Barns Ness Coast was re-notified as an SSSI on 30 April 1984 under the Wildlife and Countryside Act 1981, continuing recognition of the coast’s geological and biological importance.

1986 – Dunbar district geology synthesised
A new Geological Survey memoir brought together the geology and earlier research of the Dunbar district, including the Catcraig–Barns Ness succession. It became a principal reference for later descriptions of the coastal section.

1993 – Catcraig limestone microfossils investigated
Ali Mohamed Karbub’s detailed study of Lower Carboniferous foraminifera and limestone microfacies included the Catcraig shore section, adding microscopic fossil evidence to the interpretation and correlation of its marine beds.

1993 – Limekilns and quarries scheduled
The Catcraig limekilns, associated limestone quarries and mooring place were scheduled as a monument on 26 April 1993, recognising the national importance of this industrial coastal landscape.

2004 – National review highlights the coast’s geological importance
The published Geological Conservation Review identified Barns Ness as a key link between the Lower Carboniferous successions of Scotland and England. It highlighted the marine fossil beds, coal seams, coral-rich limestones and ancient soil and solution features exposed along the coast.

By spring 2018 – Loss of the old geological trail reported
The removal of the old geological trail was reported, and work was under way with the council towards a replacement information board near the limekiln. This marked a change in how the shore’s geology was interpreted for visitors.

2019 – Rock structure linked with living shore communities
Research at Barns Ness compared adjacent sandstone and limestone shore platforms using field ecology, rock tests and detailed surface surveys. It showed how differences in the rocks and their crevices and pools helped shape the habitats available to living intertidal organisms.

2021 – The ancient forest’s ecology reconstructed
A study of the Catcraig palaeosol, root casts and preserved plant remains tentatively proposed that the forest was dominated by cordaitalean trees. The evidence was interpreted as indicating a peat-forming coastal or lagoon-margin wetland that was not permanently flooded.

2024 – Catcraig coal included in molecular fossil research
Coal from Catcraig was analysed in a comparative study of the molecular remains of ancient plants. Chemical and stable-carbon-isotope measurements added a further line of evidence for investigating the vegetation and peat-forming environments preserved in Palaeozoic coals.

The account below follows the succession upwards, from the oldest exposed beds at Catcraig towards the younger rocks around Barns Ness lighthouse. The shore is faulted and gently folded, and beach deposits conceal some intervals, so it is not one uninterrupted vertical section. Traditional local limestone names are retained beside their current BGS equivalents to help readers use the published field guides. The rocks described are Carboniferous, Mississippian and Brigantian; the wider age ranges of the formations do not define the precise age of every bed on this walk.

Clarkson’s excursion, the Geological Conservation Review (GCR), Whyte’s 1973 thesis, Karbub’s 1993 measured section and the 1986 Dunbar memoir record different thicknesses and sometimes use different interval boundaries. Their observations are kept separate below. The fine divisions and thin-section samples are parts of these independent records, not extra beds to add together. No formal Member is introduced: the historical Longcraig Member terminology does not establish a current BGS member-level subdivision for this account.

STRATHCLYDE GROUP

Aberlady Formation

Lowest exposed mudstone and sandstone. Only the uppermost part of the Aberlady Formation is seen here. The Lower Longcraig Limestone is known from boreholes but is not exposed on this central foreshore. Clarkson’s general succession shows 0.5 m of mudstone beneath 1.5 m of sandstone; his western sandy exposures contain Zoophycos and U-shaped tubes. Whyte describes 0.5 m of thin-bedded silty sandstone passing upwards into a massive 1 m sandstone post with small calcareous nodules and abundant Zoophycos on its upper surface. Karbub records 1.60 m of very fine grey to pale-brown laminated sandstone, while the GCR summarises approximately 2 m of bioturbated marine sandstone. These are alternative descriptions of the basal exposed interval.

Middle Longcraig Limestone: nodular base and coral-rich upper beds. This pale-grey to cream limestone forms a broad wave-cut platform near the old limekiln. The lower beds are nodular and locally muddy, with crinoid debris, brachiopods and bryozoan fragments; Whyte also records Hydreionocrinus at Catcraig, while expressly excluding the trilobite occurrence in his comparison with Longcraig. The more massive upper beds carry extensive colonial-coral concentrations, solitary corals and clusters of productoid brachiopods. The branching colonies include Siphonodendron junceum, called Lithostrotion junceum in the older literature. Their weathered appearance gave rise to the name “Macaroni Rock”. Clarkson reports 1.2 m, the GCR 2 m and Karbub 1.84 m for the limestone. The memoir’s 0.69–2.87 m range, most commonly about 1.5 m, describes the district; Whyte’s 0.8–1.7 m measurement belongs to Longcraig rather than this shore.

Middle Longcraig microscopic textures. Within Karbub’s 1.84 m section, the interval 0.50–1.20 m above the base is a packstone to grainstone rich in reworked skeletal particles. The 1.70–1.84 m interval is lime mudstone with a much sparser fauna. The particles include foraminifera, algae, crinoids, ostracods, brachiopods, echinoids and gastropods. These sampled textures add detail to that measured section; they are not a second set of separately named beds.

Hollowed limestone top, fossil soil and coal. Basin-shaped hollows, commonly around a metre across and reaching 0.5 m deep in Whyte’s account, indent the upper limestone surface. Blue-grey clay fills the hollows, and the limestone is locally rubbly, brecciated-looking or dolomitised. Roots and rootlets penetrate it; the overlying ganister and fireclay contain carbonaceous streaks and Stigmaria. Siderite-rich cylindrical root concretions, soil-formed carbonate and bleaching that crosses bedding record alteration during emergence. Whyte measured 0.100 m of coal at Catcraig; Clarkson’s simplified table gives a 0.1 m coal-and-seatclay position. The memoir describes carbonaceous mudstone or impure coal above the clay. The soil and coal mark a break from marine deposition before the sea returned.

The hollows have attracted several interpretations. The memoir considered interference between growing coral colonies or early limestone dissolution, whereas the GCR interpreted a palaeokarst surface modified by soil formation. A later study of the palaeosol, root casts and plant remains tentatively reconstructed a cordaitalean-dominated forest. The rooted surface is firmly documented, but the forest interpretation does not establish that every hollow was produced in exactly the same way.

Return of marine mud deposition below the Hurlet Limestone. The soil and coal are succeeded by shell-rich calcareous mudstone. Clarkson’s general table labels a 2 m mudstone interval and his description identifies horizons rich in Eomarginifera, Streblopteria and small crinoid debris. Karbub’s independent account records 0.53 m of bivalve-bearing silty mudstone above the clay-filled hollows, then 0.10 m of coal and 0.60 m of calcareous silty shale, totalling 1.23 m for those three units. His upper shale contains brachiopods, crinoids, bryozoans, ostracods and rare Earlandia. These descriptions should not be combined into an artificial total or used to reverse the locally observed coal-to-marine-shale transition.

Whyte’s lower transgressive shale division: 0.160 m. The lowest of his three shale divisions below the Upper Longcraig Limestone is silty and relatively barren. A few thin-shelled bivalves were found at Catcraig.

Whyte’s middle transgressive shale division: 0.120 m. This shell-rich division contains Schizophoria resupinata and Streblopteria ornata, together with pedicle valves of Orbiculoidea reaching 30 mm across.

Whyte’s upper transgressive shale division: 0.430 m. Abundant Eomarginifera longispina characterises this division, which grades upwards into the lowest limestone post. The three divisions total 0.710 m. They lie beneath the limestone base and therefore below the local formation boundary.

CLACKMANNAN GROUP

Lower Limestone Formation

Hurlet Limestone, locally the Upper Longcraig Limestone. The base of this limestone marks the base of the Lower Limestone Formation and Clackmannan Group. Pale-grey limestone posts with undulating surfaces are separated by thin shale partings. Crinoid and shell debris, brachiopods and colonial corals occur through it, with local recrystallisation and dolomitisation obscuring detail. Clarkson and the GCR give 6 m; the memoir records up to 7.67 m at Cat Craig. Whyte’s 6.5–9.0 m range is from APCM boreholes, not a single shore measurement. Karbub instead reports a 1.84 m logged limestone interval, supported by his figure and sampling chart, with bioclastic wackestone and packstone containing foraminifera, ostracods and algae. This unresolved difference is retained rather than silently corrected or averaged.

Upper Longcraig coral band, the “Dunbar Marble”. A conspicuous concentration of solitary rugose corals, dominated by Koninckophyllum, occurs about a metre below the limestone top. Clarkson records a band about 0.25 m thick, and Karbub also describes a 0.25 m coral-rich interval. The GCR uses the historical name Koninckophyllum echinatum. Whyte reports 0.2–0.7 m across his study localities and notes that the band is absent in places at Catcraig. The memoir’s regional description gives up to 0.31 m, approximately 0.90 m below the top. The coral concentration is thus a useful marker, but not a uniform sheet of identical thickness.

Upper Longcraig top surface. Whyte records a ferruginous stain at Catcraig. The 80 mm ironstone cap with Wilkingia that he described at inland Dunbar Works was explicitly absent on the Catcraig shore and is not part of this local log.

Mudstone and sandstone below the Lower Skateraw Limestone. Marine deposition gave way to muddy and then sandy conditions. Clarkson and the GCR summarise a 5 m clastic interval: plant-bearing mudrocks, thin ripple-marked sandstones, trails and other traces, capped by a rooted or coaly position. Whyte describes the complete flat-lying Catcraig exposure but does not give it a separate precise total; his 4.9–7.5 m range belongs to boreholes. Karbub records 4.9 m, beginning with 0.15–0.20 m of dark mudstone and followed by thicker bioturbated, cross-bedded sandstone with asymmetric ripples. The memoir’s district interval is 5.5–6.5 m and notes that sandstone can cut out the underlying mudstone. Near the old hydraulic ram, a small-displacement dolomitised fault stands as a resistant wall: its dyke-like appearance is caused by alteration along a fault, not by an igneous intrusion.

Lower Skateraw Limestone. A relatively thin, fine-grained grey to brown limestone contains abundant crinoid ossicles and conspicuous large productoid brachiopods, including Gigantoproductus. The GCR describes one principal post, with gigantoproductids near the base and colonial corals and bellerophontid gastropods towards the top. Clarkson and the GCR give about 1 m; the memoir records 0.56 m at the coastal exposure east-north-east of the kiln, and Karbub measures 0.52 m. Karbub’s thin sections show muddy bioclastic textures, with abundant foraminifera and calcareous algae. The published regional comparison with the Shields/Inchinnan horizon is a correlation, not an additional member or bed here.

Lower–Middle Skateraw clastic and rooted interval. Silty mudstone with ironstone concretions passes into silty sandstone, then rooted grey fireclay and a thin coal. Whyte gives a Catcraig total of 3.6 m. His component description, shared with Skateraw, comprises 2.2–2.5 m of basal silty mudstone, 0.8–1.0 m of sandstone containing sheet-like and root-like ironstone, 0.5 m of Stigmaria-rich fireclay and 0.020 m of coal. The sandstone top has irregular polygonal markings. Those shared component ranges are not separately measured Catcraig values and cannot be forced to sum to the local total. The GCR gives 3.8 m; Clarkson shows 3 m of mudstone and a 0.1 m coal-and-seatclay position. Karbub records 2.05 m, including up to 1.6 m of silty mudstone, a rooted bed and 0.10 m of coal. The memoir’s 2.34–7.32 m interval and approximately 0.15 m coal are district observations. All these records preserve emergence and vegetation before renewed marine flooding.

Blackhall Limestone interval, locally the Middle and Upper Skateraw limestones. Current BGS terminology relates both traditional Skateraw names to the Blackhall Limestone. Their different local beds and the intervening mudrocks remain distinguishable and are described separately here. The thick lower limestone, historically Middle Skateraw, begins above a thin dark marine shale with fossil shells and fusain fragments. It consists of pale-grey to brownish crinoidal limestone posts separated by dark calcareous siltstone, mudstone or shale, with rugose corals, brachiopods and abundant skeletal debris. Clarkson reports 4 m, the memoir 4.1 m at its Catcraig foreshore point, the GCR 5 m and Karbub 3.48 m, including partings up to 0.1 m. Whyte’s lettered log is given independently below; another author’s total is not imposed upon it.

Distinctive Middle Skateraw fossil concentrations. Lower posts contain large productoid shells, Zoophycos and chaetetid sponges. Chaetetes colonies can be rounded and bun-shaped or flattened discs; the flat colonies overlie lenses of crinoid and other shell debris, some of it coated by algae. The lenses may be protected remnants of a wider accumulation or small patches upon which the sponges grew. Near the top, dense Saccamminopsis bodies form a recognisable band, described as about 0.25 m thick by Clarkson and Karbub. On weathered surfaces they appear as small orange-brown rounded bodies, commonly 2–3 mm across. Saccamminopsis is a problematic calcareous fossil often interpreted as algal, rather than a securely identified foraminifer. Above it lies a thin muddy cap with patches of disarticulated echinoid test plates.

Whyte’s Middle Skateraw beds, oldest to youngest. Whyte’s Table 1 lettered the succession downwards from a to q; the order below reverses it to follow upward growth of the rock sequence. Thicknesses are the explicitly printed Catcraig measurements. His fossil descriptions accompany correlated beds across Catcraig, Skateraw and Dunbar Works, so the pooled fossil lists below do not independently prove that every named fossil was collected from that particular Catcraig bed. Bed a specifically records the Catcraig echinoid material.

Bed q: basal shale, 0.14 m. The correlated-bed description records crinoid columnals, Anemetocrinus and Ureocrinus, productoid and Spirifer brachiopods, solitary corals, bryozoans, echinoid spines, possible Weberides and coal fragments. This is the shaly marine base of the limestone succession.

Bed p: limestone, 0.28 m. Whyte gives the same pooled assemblage as for bed o: Chaetetes, gigantoproductids and other productoids, Zoophycos, fish remains, and large and small crinoid columnals.

Bed o: limestone, 0.25 m. The correlated-bed description includes Chaetetes, gigantoproductids and other productoids, Zoophycos, fish remains and crinoid columnals. The explicit Catcraig thickness is 0.25 m; the table’s inconsistent printed average of 0.37 m is not used as the local measurement.

Bed n: shale, 0.02 m. This thin parting separates the lower limestone posts.

Bed m: limestone, 0.08 m. The correlated description records Chaetetes, Zoophycos and large crinoid columnals.

Bed l: shale, 0.06 m. A further distinct shale parting interrupts limestone deposition.

Bed k: limestone, 0.20 m. Rare Chaetetes is noted in the correlated-bed description.

Bed j: dark shale, Catcraig thickness unknown. The table prints the Dunbar Works 10 mm label twice and gives 60 mm for Skateraw, without an identifiable Catcraig value. No local measurement or complete summed total is inferred from this apparent printing error.

Bed i: limestone post, 0.70 m. This thicker limestone succeeds the dark shale of bed j.

Bed h: dark shale, 0.02 m. Fossil fragments occur in this thin parting.

Bed g: nodular limestone with shale, 1.70 m. The thickest Catcraig division in the lettered log contains nodular limestone interspersed with shale. The pooled description includes brachiopods, gastropods, crinoids and rare Saccamminopsis, with possible algal coatings around some skeletal debris.

Bed f: dark shale, 0.06 m. Whyte describes this parting as unfossiliferous.

Bed e: limestone nodules in dark shale, 0.18 m. The same limestone-nodules-in-dark-shale development is recorded at Skateraw; Dunbar Works has nodular limestone.

Bed d: limestone post, 0.08 m. This thin post lies between the nodular interval and the upper dark shale.

Bed c: dark shale, 0.10 m. This unfossiliferous shale immediately underlies the principal Saccamminopsis bed.

Bed b: Saccamminopsis-rich limestone, 0.49 m. Fossil-rich lenses coalesce within this recognisable upper band; recrystallisation affects their preservation. The 0.49 m belongs to Whyte’s whole lettered Catcraig bed and should not be substituted for, or averaged with, the narrower 0.25 m concentration described by other authors.

Bed a: argillaceous echinoid cap, 0.05 m. Patches of abundant disarticulated echinoid plates lie on the upper surface. Whyte specifically records Catcraig material as Lepidesthes caledonica, Archaeocidaris and possible Melonechinus, together with crinoid debris. The qualification on the last identification is retained; disarticulated plates are not evidence that complete sea urchins are a routine find.

Karbub’s separate Middle Skateraw petrofacies, 0–0.20 m. The lowest sampled interval of his 3.48 m section is dark bioclastic packstone, with brachiopod, bryozoan and crinoid fragments and rare foraminifera.

Karbub’s 0.20–0.40 m interval. Dark peloidal wackestone contains a less abundant microscopic fauna.

Karbub’s 0.40–1.40 m interval. Pale-grey bioclastic wackestone and packstone show an increase in foraminifera and algae.

Karbub’s 1.40–3.35 m interval. Dark, partly dolomitised wackestone contains reworked and broken foraminiferal tests. Rare geopetal fabrics, recording the orientation of sediment infill within cavities, appear from about 2.50 m upwards. Saccamminopsis occurs at sampled levels of 1.4, 2.3, 2.9 and 3.1 m, while the microscopic fauna becomes less abundant above 2.10 m. These are sample positions in Karbub’s section, not correlations to individual Whyte letters. The highest sample at 3.35 m and his total thickness of 3.48 m do not define an otherwise undescribed extra bed.

Tectonic breccia above the Middle Skateraw, 0.025 m. Whyte records a thin zone of limestone and mudstone fragments in red clay at Catcraig. Its relationship to deformation distinguishes it from a deposited conglomerate or the base of a new marine cycle.

Whyte’s basal post-Middle Skateraw shale, 0.300 m. Occasional dark, fossil-free laminae occur within the shale. It was so shattered at Catcraig that Whyte could not extract the complete interval for his quantitative fossil collections; this sampling limitation matters when comparing the coastal faunas.

Whyte’s overlying marine mudstone, 0.700 m. This bioturbated, slightly fissile mudstone was fully sampled. Pyrite and siderite occur within it, and its overall character resembles the Skateraw equivalent. It is a separate sampled division above the shattered shale.

Local Upper Skateraw lower ironstone leaf, 0.120 m. At Catcraig this calcareous ironstone has an irregular, flaggy appearance and is thicker than its counterpart at Skateraw.

Local Upper Skateraw internal shale, 0.020 m. A thin shale separates the lower ironstone from the upper limestone leaf.

Local Upper Skateraw upper limestone leaf, 0.340 m. This limestone completes Whyte’s compound unit. Together the ironstone, shale and limestone make 0.480 m; the 0.340 m upper leaf is not the thickness of the whole unit.

Alternative post-Middle Skateraw records and marine communities. Clarkson describes 1.5 m of fossil-rich calcareous mudstone and a 0.5 m Upper Skateraw limestone, pale brown when weathered and containing haematised nodules. The GCR gives 1 m and 0.4 m respectively; Karbub gives 1.2 m of marine mudrocks and 0.36 m of argillaceous crinoidal limestone. In contrast, the memoir describes just over 9 m of shelly silty mudrocks at its Catcraig coastal point, including one 0.15 m limestone, and suppresses the Upper Skateraw name because impersistent leaves occur within the same marine cycle. Its broader interval is not directly equivalent to Whyte’s metre of sampled shale and mudstone. Brachiopods, bivalves, solitary corals, trilobite fragments and crinoid debris make the coastal mudrocks especially informative. They represent the off-bank equivalent of a thicker inland mudbank, not the exposed crest of that bank. Whyte recorded Weberides mucronatus at Catcraig, but his Parazeacrinites konincki material came from Dunbar Works and was expressly not recorded at Catcraig or Skateraw.

Basal mudstone above the local Upper Skateraw. Up to about 1 m was intermittently exposed at Catcraig in Whyte’s study, yielding sparse zaphrentid corals and a few crinoid ossicles. The fuller fossil lists from other study localities should not be transferred to this thin coastal exposure.

Higher mudstone, siltstone and sandstone beneath the Main Hosie Limestone. The poorly exposed succession coarsens upwards and becomes sandier, with ledges of sandstone alternating with fissile mudstone, patchy carbonate cement, traces on bedding surfaces and occasional septarian concretions. Clarkson assigns 27 m to the clastic interval and shows a 0.2 m coal-position/seatclay horizon above it; the GCR gives about 30 m, while Whyte estimates approximately 30 m and describes the Catcraig beds as siltier than those at Skateraw. Karbub’s figure shows the interval without a separate measured total. Roots, plant debris and ganister-like sandstone record the return of terrestrial conditions; Whyte places the overlying limestone directly on ganister. The memoir records no coal in this particular upper rooted development, so a persistent exposed coal seam should not be assumed from the simplified field-guide column. It also describes coarse erosive sandstones near the lighthouse cutting out more marine beds. A higher Spirifer-bearing marine band recognised elsewhere was not located at Catcraig by Whyte and is not a guaranteed stop here.

Main Hosie Limestone, locally the Chapel Point Limestone. This grey limestone weathers brown or yellow-brown and is locally dolomitic, sandy and thoroughly bioturbated. Crinoid debris is abundant in its sandy base. Small colonies of Siphonodendron occur on some lower bedding planes, while uncommon bellerophontid gastropods are recorded towards the top. Middle beds contain chert nodules with sponge spicules and fine skeletal debris. At Barns Ness its upper surface has valves historically identified as Spirifer trigonalis and spines of Archaeocidaris. Complete Archaeocidaris specimens reported from Millstone Neuk belong to a different locality. Clarkson records 3 m, the GCR 2.8 m, Karbub 2.45 m and the memoir 2.4 m at the foreshore north of the lighthouse; Whyte’s 2.6–2.9 m spans his study localities. Karbub describes recrystallised dolomitic wackestone in which rare ghosts of Palaeotextularia remain visible.

Main Hosie trace-fossil horizons and sandstone transition. Clarkson’s description provides a useful upward sequence: horizontal U-shaped Rhizocorallium, sometimes sinuous and reaching about 50 cm long, in the lower part; sweeping or concentric Zoophycos higher up; branching horizontal Thalassinoides and fan-shaped traces at some levels; and large vertical U-shaped Diplocraterion where the limestone grades into sandstone. Sand content increases towards the top. These structures record activity within the sediment rather than preserved coral colonies or the bodies of their makers.

Sandstones above the Main Hosie Limestone. Fine- to coarse-grained, locally cross-bedded sandstones contain thin siltstones, ironstone nodules, patchy sideritic cement, roots and plant debris. Large concretions are also described in this sandy development. Near the top are large sandstone-filled casts of Stigmaria, together with smaller rootlets. The upper sandstone is hard, siliceous and ganister-like. These deposits record renewed input of land-derived sediment into a shallow coastal setting. Clarkson gives 10 m for the clastics, while the memoir describes a district range of 9–11 m; Karbub quotes 9 m from the memoir rather than providing another independent measurement. The GCR’s approximately 12 m and Whyte’s 12–13 m describe broader intervals that already include the Barns Ness limestone near their top. They must not be read as those thicknesses of sandstone plus an extra limestone.

Mid Hosie Limestone, locally the Barns Ness Limestone, and the upper sandstones. The sandy, fine-grained grey to brown limestone contains crinoid debris and Zoophycos, with generally fewer obvious body fossils than the lower marine limestones. Karbub records dolomitisation, rare Palaeotextularia and an increasingly quartz-sandy top. Clarkson and the GCR give about 1 m and Karbub 1.1 m; the memoir’s 0.3–1.8 m is a district range, with thinning and eventual disappearance north of the lighthouse. Current BGS terminology identifies it with the Mid Hosie Limestone, also called Middle Hosie. The old Barns Ness and Dryburnfoot names should not create two successive beds. Nor does the memoir’s formerly uncertain Top Hosie comparison establish a local Namurian boundary. Current-bedded sandstone and large spherical or barrel-shaped sideritic concretions occur above the limestone. The memoir’s approximately 30 m of sandstone east of the lighthouse extends beyond the core walk and is not added as a fully exposed local section.

Correlation and the limits of the record. These marine and non-marine cycles link the Lower Carboniferous succession of south-east Scotland with northern England. Modern foraminiferal work supports a Brigantian framework and regional comparison of the Middle Skateraw with the Blackhall/Three Yard horizon. Its wider Cove–Skateraw–Dunbar sampling does not establish a new exact Catcraig age for every sampled bed. Local dolomitisation, erosion, lateral thinning, structural repetition and temporary beach cover all affect what can be recognised on a particular visit.

References
Clarkson, E.N.K. (1987). Catcraig, in McAdam, A.D. & Clarkson, E.N.K. (eds), Lothian Geology: an excursion guide. Excursion and map.
Whyte, M.A. (2004). Barns Ness Coast, in Cossey and colleagues, British Lower Carboniferous Stratigraphy, Geological Conservation Review Series 29. Site account.
Whyte, M.A. (1973). The palaeoecology of Upper Visean marine mudstones, near Dunbar, East Lothian. University of Edinburgh PhD thesis, especially the coastal sections and Table 1. Thesis.
Karbub, A.M. (1993). Foraminiferal Biostratigraphy and Microfacies of the Lower Carboniferous rocks, Central Scotland. University of Edinburgh M.Phil thesis, pp. 22–30 and distribution charts. Thesis.
Davies, A., McAdam, A.D. & Cameron, I.B. (1986). Geology of the Dunbar district. British Geological Survey memoir, particularly pp. 24–27. Memoir.
British Geological Survey. Lexicon of Named Rock Units: Aberlady Formation, Lower Limestone Formation and linked limestone entries.
Alekseeva, T.V., Mitenko, G.V. & Alekseev, A.O. (2021). The ecology of a late Visean forest at Catcraig (East Lothian, Scotland) based on multiproxy study of paleosol and root-casts. Palaeoworld 30, 62–71. Abstract and article details.
Cózar, P. & Somerville, I.D. (2020). Foraminiferal biostratigraphy of Brigantian–Arnsbergian limestones from eastern Scotland and Northumberland. Research article.