Joppa Shore Fossil Hunting

1886 – Shore macrospores documented and illustrated
James Bennie and Robert Kidston described lycopod macrospores from two shore localities near the salt pans, including specimens illustrated as historical Triletes forms VI and IX. Bennie’s Geological Survey collecting underpinned the study, with Kidston undertaking the botanical work. The paper was read on 21 April and appeared in a session part dated 1886; the completed volume carries an 1888 imprint. These dates do not establish when the individual fossils were collected.

1910 – A detailed shore section and fossil-locality record published
A measured section credited to W. Gibson and D. Tait documented the succession from the upper limestone beds through the Roslin sandstones into the lower Coal Measures. Its folding illustration distinguished marine ironstones, thin coals, fireclays and three plant beds. Numbered shore localities preserved the positions of historical plant, shell and fish records, while the accompanying description acknowledged that some concealed coal-seam positions remained uncertain.

1936–1937 – The important Carbonicola assemblage reinterpreted
Later accounts credit Leitch’s study of variation in the Fifteen Foot Coal fauna with showing that Joppa shells previously called Carbonicola robusta belonged to the broader C. communis complex. This became evidence for a middle Langsettian age. The study is conventionally cited as 1936, while its publisher dates it January 1937; this is a publication milestone, rather than a dated new fossil discovery.

1953 – Conodont-bearing horizons systematically sampled
William J. Clarke’s doctoral study documented fifteen sample identifiers at Joppa Shore. Productive samples included shaly parts of the numbered marine ironstones and shale associated with Castlecary Limestone, adding microscopic fossil evidence to the shore’s better-known shells and plants. The sample record distinguishes positive results from horizons that were merely sampled; it does not represent fifteen new fossil species.

1958 – Detailed beds and distinctive faunas strengthen correlation
W. Tulloch and H. S. Walton published detailed Joppa logs that separated limestone leaves, muddy partings, marine bands, thin coals and fossil-bearing roof beds. R. B. Wilson’s palaeontological work showed how distinctive assemblages recognised through comparisons involving Joppa could help correlate isolated exposures across the Midlothian Basin. The contrasting faunas below Calmy and within the Calmy–Castlecary interval were especially useful.

1962 – The shore recognised as a key Passage reference succession
The district’s revised geological account adopted the name Passage Group for rocks previously described as the Roslin Sandstone Group or Millstone Grit. It identified Joppa as probably the most reliable and best-documented local succession and reproduced it in a comparative section, reinforcing the shore’s role in interpreting this interval despite uncertain correlations between individual marine bands.

1996 – Roslin and lower Coal Measures significance synthesised
A major conservation assessment treated Joppa as the type and best exposure of the Roslin Sandstone Formation in its contemporary framework and highlighted its lower Productive Coal succession. It brought together the plant beds, river and delta sandstones, marine ironstones and non-marine bivalve age evidence. That historical Roslin type designation is distinct from the current Passage Formation, whose type section is the Airth Borehole.

2004 – Upper Limestone fossil succession placed in a wider framework
A further geological assessment emphasised the shore’s upper Upper Limestone succession, including Calmy, Castlecary and the intervening fossil bands. It highlighted the Edmondia punctatella horizon and the diverse marine fauna in the Plean-equivalent beds as valuable markers for regional correlation. This was a synthesis of the site’s scientific importance, rather than a claim that those fossils had just been discovered.

2025 – Modern-named district synthesis published
A district report illustrated Castlecary’s separate limestone leaves at Joppa and described the overlying Passage succession using modern formation names. Its Joppa thickness estimate and marine-band count differ from older accounts and require careful comparison. Although published in 2025, the report explains that most of its geological understanding reflects work completed by the early 2000s, so this is not evidence of a new 2025 field discovery.

Reading the shore succession. Joppa exposes the upper part of the Upper Limestone Formation, followed by the Passage Formation and the lower part of the Scottish Lower Coal Measures Formation. The beds dip steeply eastwards on the western limb of the Midlothian Syncline; the 1958 memoir records dips of 50–60°. Moving across the shore therefore crosses successive beds rather than following a horizontal layer. Faults, worked coal seams and patches of sand, mud and boulders interrupt the section. The descriptions below record published observations, including beds that were already concealed when those accounts were written; they do not imply that every bed is visible today.

Names, measurements and fossil records. The account follows the succession upwards, from older to younger rocks, except where a historical log is explicitly described in another direction. Measurements in feet and inches are retained for the detailed historical logs so that their individual beds remain traceable; metric figures from later summaries are identified separately. These overlapping logs must not be added together. In the older Scottish descriptions, “blaes” means shale or mudstone, “fakes” denotes thinly bedded silty or sandy material, “parroty” describes a cannel-like carbonaceous rock, and fireclay commonly represents an old soil beneath a coal. Fossil names in historical lists retain their original qualifications and are not presented as modern redeterminations.

CLACKMANNAN GROUP

Upper Limestone Formation: upper part

Extent and age. The exposed upper succession is Arnsbergian in age and was described in older memoirs as part of the Upper Limestone Group. The 2004 Geological Conservation Review describes approximately 175 m, probably incomplete through faulting. This is an exposed interval, not the full thickness of the formation. Its local landmarks include the Wood Coal, Calmy Limestone, intervening marine and non-marine fossil bands, and Castlecary Limestone. Although the formation begins regionally at the Index Limestone, neither that regional boundary nor the lower limestone succession is the start of the documented shore section. Joppa Quarry belongs to a separate exposure history.

Basal sandstone and Wood Coal. The later GCR account begins with a massive sandstone below the Wood Coal. The coal had been worked and was no longer exposed. The 1910 folding section likewise shows partly concealed sandstone followed by a thick coal recorded as formerly exposed. Above this, its older labels include about 6 ft of parroty shale over fireclay and a concealed limestone marked “No. 5 (Arden)”. This is the historical label for Calmy Limestone, not an additional limestone in the modern succession.

Wood Coal to Calmy: lower sandy beds in the 1958 log. Starting above the gap at the Wood Coal position, the measured section rises through 16 ft of grey, mica-bearing sandstone with plant material and then 9 ft of brown sandstone. Above these are 2 ft of dark fakes and silty mudstone, 3 ft of grey sandstone with dark micaceous laminae, and 5 ft of dark fakes containing many irregular ironstone nodules near their base. A 6 ft grey sandy fireclay with black roots caps this part of the succession, preserving evidence of vegetation growing on the sediment surface.

Wood Coal to Calmy: rooted floor and fish-bearing beds. Above the fireclay lie a separate 2 in dark sandstone and 1 ft 3 in of dark fakes and sandstone. These are followed by 3 ft of parroty mudstone with ironstone nodules and ribs near its top, a hard dark ferruginous rib 6 in thick containing fish remains, and another 2 ft 6 in of fish-bearing parroty mudstone. A 1 ft layer of soft, crushed mudstone separates these carbonaceous beds from the first substantial marine shale.

Lower marine shale and the Edmondia-rich sub-band. The next 11 ft consists of grey mudstone with historical records of Lingula mytilloides, Actinopteria? cf. persulcata, Edmondia punctatella and Sanguinolites cf. clavatus. Within this bed, E. punctatella was particularly numerous in a band about 3 ft above its base. That figure locates the fossil band; it is not the band’s thickness. The GCR describes a corresponding 3.5 m marine shale with the enriched horizon about 1 m above its base, but prints Actinopteria cf. persculpta. The differing name and qualification are retained as a source discrepancy rather than silently harmonised.

Wood Coal to Calmy: middle siltstones and sandstones. Above the lower marine shale, the 1958 log records 4 ft of dark silty mudstone, 7 ft of grey fakes, 16 ft 6 in of interbedded fakes and sandstone, and 20 ft of pale brown and grey sandstone containing silty and sandy interbeds. A further 1 ft 9 in of grey fakes with sandstone ribs leads into the second marine shale. This succession preserves the change from finer sediment to more sand-rich conditions between marine incursions.

Upper marine shale below Calmy. The second shell-bearing bed is 5 ft of dark grey mudstone. Its 1958 fauna includes Lingula mytilloides, Cardiomorpha cf. limosa, a poorly preserved pectinid, Prothyris cf. elegans, Sanguinolites cf. clavatus, S. cf. striatus, Bucanopsis sp. and borings identified as Conchotrema sp. in a bivalve shell. It also records an unnamed Sanguinolites form of the variabilis–omalianus group, using “sp. nov.” descriptively; this is not a verified modern species name. Above the shale are three separate units: 1 ft 6 in of fakes with sandstone laminae, 3 ft of grey sandstone with silty layers, and 1 ft 2 in of fakes with sandstone ribs and mudstone immediately beneath Calmy.

The later summary below Calmy. The GCR groups this succession differently: 12 m of sandstone and silty sandstone capped by pale seatearth above Wood Coal; 2 m of dark and bituminous fish-bearing shale with ironstone nodules; the 3.5 m lower marine shale; 8 m of siltstone and sandy siltstone; 7 m of sandstone with silty layers; a 1.5 m upper restricted-marine shale; and 1.5 m of siltstone and sandstone beneath Calmy. These rounded packages provide a useful overview but do not replace the finer 1958 log, whose measured rows between the Wood Coal gap and Calmy total 120 ft 4 in, approximately 36.68 m. Their component totals are not demonstrably identical.

Calmy Limestone: two leaves and a muddy parting. Calmy is the No. 5 (Arden) Limestone of the older section. In the 1958 Joppa description, the lower leaf is 2 ft 9 in of brown-grey limestone. It is overlain by 6 in of mudstone and then a 1 ft grey limestone with reddish veins. Crinoid columnals and the historical brachiopod determinations Productus (Gigantoproductus) cf. latissimus, P. (Sinuatella) sp. and Spirifer sp. are specifically attached to the upper leaf. Including the parting gives about 1.30 m, consistent with the GCR’s rounded 1.3 m; the net limestone thickness is smaller. Calmy and Castlecary are named limestone horizons within the Upper Limestone Formation.

Calmy to Castlecary: scope of the detailed log. The 1958 narrative gives about 275 ft between the limestones and notes probable loss of strata through faulting. Its detailed rows, including recorded gaps, total 274 ft 5 in, approximately 83.64 m. The following paragraphs preserve that log upwards. Several rows in the original are composite intervals, so their internal beds cannot legitimately be assigned separate numerical thicknesses. The later GCR recognises a possible fault-related gap above Calmy, about 25 m of lower sandstone-rich measures, roughly 40 m of variable fossil-bearing measures, and a final 23 m sandstone–seatearth interval. Those broader divisions are not used to manufacture a second exact total.

Immediately above Calmy and the lower composite measures. A 3 ft exposure gap is followed by 1 ft of grey fakes and 12 ft 6 in of massive brown sandstone, pebbly at its base. The next 69 ft 8½ in is a source-defined composite interval of fireclay, fakes, silty mudstone, mudstone, sandstone and a few thin coals, with several small gaps. Above it, a separate 3 in coal with thin fireclay ribs is capped by 1 ft 2 in of hard mudstone, carbonaceous at the base, with clayband ironstone ribs and Lingula mytilloides.

Lower shell bed in the Plean-equivalent interval. Next come 15 ft 4 in of fireclay, sandstone, fakes and a thin coal, followed by a 6 in gap and a distinct 1 ft coal. Above that coal are 6 in of dark, pyritised fakes with Lingula, then 4 ft 6 in of silty mudstone and mudstone containing Nuculana attenuata, questioned Edmondia sulcata and questioned Sedgwickia suborbicularis. These restricted and marine faunas occupy successive beds; they should not be combined into one undifferentiated limestone fauna.

Further Lingula and Anthraconauta beds. Above the lower shell bed are 9 ft ½ in of sandstone and fakes, a 5 in coal, and a separate 1 ft mudstone carrying thin ironstone ribs, fish remains and Lingula cf. mytilloides. The next composite interval, 21 ft 3 in thick, consists of fireclay in sandy and silty varieties together with sandy fakes and fakes. A 1 in coal is followed by 7½ in of soft mudstone with thin clayband ironstone ribs and Anthraconauta sp. Above this lies another composite package, 34 ft 11 in thick, containing fireclay, fakes, parroty mudstone and thin coals.

Rich marine interval: lower mudstones and the thin limestone. The next 3 ft 6 in consists of fossiliferous silty mudstone and fakes. Above it are 5 ft 10 in of grey marine mudstone, becoming silty towards its base and containing ironstone nodules. These are overlain by a separate grey, earthy limestone lens only 1½ in thick. Although small, this carbonate bed is a documented part of the marine interval and should not disappear into a general shale description.

Rich marine interval: upper shell-bearing mudstone. Above the limestone lens, 2 ft 6 in of grey mudstone and silty mudstone contains numerous marine fossils in its lower part. The 1958 list includes a fenestellid bryozoan, Orbiculoidea sp., Productus (Dictyoclostus) aff. muricatus, Schellwienella sp., questioned Parallelodon semicostatus, Schizodus cf. triangularis, Sulcatopinna flabelliformis and Bucanopsis sp. A second productid is printed “pugills” in the digitised table but pugilis in the memoir’s discussion. The later GCR uses Fenestella, Antiquatonia cf. muricata and Pugilis cf. pugilis for this rich assemblage. These are source-era taxonomic treatments, not new identifications of the original specimens.

Correlation of the fossil bands. The 1958 discussion distinguishes two marine bands, two Lingula bands and an Anthraconauta band within the Calmy–Castlecary measures. It places the richly fossiliferous upper marine band about 87 ft below Castlecary. These horizons were compared with the Plean limestones of the Central Coalfield, but individual band-to-band correlations were explicitly uncertain. The GCR regards the rich marine fauna as exceptionally diverse within those equivalents. “Plean-equivalent” is therefore a correlation description here, not a newly named Joppa member.

Above the rich marine shale: roots, ironstone and another Lingula band. The measured sequence continues through 5 ft 6 in of dark plant-bearing fakes with many lenticular ironstone ribs and nodules, then 2 ft 3 in of grey sandstone and fakes with roots. An 8 in exposure gap precedes a separate 7 in dark silty mudstone with Lingula mytilloides and possible bivalves. The GCR places a higher Lingula horizon about 3 m above the marine shale; this is a height above a bed, not a 3 m fossil-layer thickness.

Upper sandstone and fireclay below Castlecary. Above that Lingula bed are 40 ft of pale brown sandstone, locally coarse-grained, and 15 ft 2 in of sandy and silty fireclay with occasional fakes layers. A 3 in hard carbonaceous fakes bed containing thin coal laminae is followed by 12 ft of sandstone, silty at its top, and 3 ft of grey plant-bearing fakes with ferruginous concretions. Above a 3 ft 6 in gap lie 1 ft 6 in of grey rooted fireclay with a dark top, a 1 in coal and coaly-fakes layer, a further 6 in gap, and finally 8 in of grey calcareous mudstone with shells and crinoid debris directly beneath Castlecary.

Additional labels in the 1910 limestone-interval section. Between its historically labelled No. 5 limestone and Castlecary, the folding plate records a 6 ft shale with ironstone courses; a coal formerly exposed over a width of 3 ft; a separate 4 in coal; and 2 ft of coaly shale. Higher labels identify formerly exposed thin coals and fireclay, a 7 in coal, and 2 ft of parroty shale. Much of the evidence is marked concealed. The quoted 3 ft is the plate’s outcrop-width wording, not a verified seam thickness. The individual equivalences between these older labels and the 1958 beds remain uncertain.

Castlecary Limestone: lower leaf and intervening mudstone. Castlecary is the No. 6 Limestone of the 1910 section. The 1958 description begins with approximately 3 ft of grey and brown limestone containing shells and crinoid debris. Above it lies 4 ft 6 in of grey shelly mudstone. This substantial parting separates the principal limestone leaves and is essential to understanding the outcrop; Castlecary is not a single unbroken limestone slab.

Castlecary Limestone: upper leaf and cap. The upper main leaf is 5 ft of crystalline blue and brown limestone with solution cavities. It is followed by 2 in of earthy calcareous fakes with shells and crinoid debris and a final 1 in dark earthy limestone cap. The approximate gross thickness of all five components is 3.89 m, compared with the GCR’s rounded 3.8 m. A photograph in BGS report OR/25/006 describes two approximately 1 m limestone units; those are the visible carbonate leaves, not a measurement of the entire limestone-plus-mudstone interval. Castlecary marks the top of the Upper Limestone Formation at this shore.

Conodont sampling below and within Castlecary. Clarke’s 1953 Joppa programme distinguishes sampled horizons from productive samples. G12, shale 3 in below Castlecary, is marked conodont-bearing. G13, G14 and G15, respectively in shale 170 ft, 230 ft and 250 ft below it, are listed without positive marks. G8–G11 sampled a 3 ft shale interval within Castlecary and share one grouped positive indication; that sampled interval is not a replacement measurement for the whole parting in the 1958 log. The thesis also records historical Hindeodella elements from Castlecary limestone and shales at Joppa. These microscopic records do not identify every limestone leaf as equally fossiliferous.

Passage Formation

Definition, age and thickness. The Passage Formation begins above Castlecary Limestone. Older accounts call these rocks the Roslin Sandstone series, Roslin Sandstone Group or Roslin Sandstone Formation, and historically associate them with the Millstone Grit. Passage Group is another former name used for this interval. The current formation spans Arnsbergian to Langsettian time regionally. The 1910 Joppa account gives 740 ft, approximately 225.6 m, and the 1996 GCR gives 225 m. BGS OR/25/006 instead lists 210 m and says that thickness is poorly known. These are separate estimates, not values to average. Although published in 2025, that report states that most of its geological understanding dates from the early 2000s.

Historical reference section and modern boundaries. Joppa was treated as the stratotype of the Roslin Sandstone Formation in the 1996 GCR framework. The current BGS Passage Formation has its type section in the Airth Borehole, so these type designations should not be confused. At its upper boundary the historical Joppa logs use the base of the Seven Foot Coal. The current regional lithostratigraphical definition uses the Lowstone Marine Band, a local equivalent or a disconformity where appropriate; that does not establish a visible Lowstone band at this shore. Neither marker should be presented as a demonstrated global Carboniferous time boundary here.

Basal Anthraconauta mudstone. Immediately above Castlecary, the 1958 account records 3 ft of shaly mudstone containing abundant Anthraconauta sp., ostracods and fish remains. Its lower part is more shaly and thin ironstone ribs occur throughout. This shore measurement must be kept separate from thicker beds at Redcroft and the detailed Gilmerton section. Clarke’s sample G7 at the limestone roof is marked conodont-bearing, whereas G6, black shale 1 ft above the limestone, is unmarked. The 1910 plate also records contorted black shale above Castlecary.

Lower gap and coarse sandstone. The 1958 memoir identifies an exposure gap of 45 ft near the base. It notes that two low marine bands known elsewhere would be concealed by mud and boulders if present at Joppa; they are not added here as demonstrated shore beds. The 1910 plate similarly marks a concealed lower interval, followed by pale sandstone with quartz conglomerate and further sandstone. Its narrative describes the lower major sandstone package as about 150 ft thick, conglomeratic below with white quartz pebbles and more flaggy near the top, lying below the lowest marine ironstones. The gap’s size is not a fault-throw measurement.

Eight marine horizons in the 1958 account. A shelly ironstone approximately 80 ft above Castlecary overlies soft grey mudstone with occasional marine fossils. This height locates the bed; its thickness is not stated. Above it the memoir explicitly records seven further marine horizons. Each is a thin mudstone band, generally containing ironstone nodules or nodular ribs. The seven higher bands are not individually named or measured in the account, which supplies no separate species list for each. Their separate existence is important: the memoir’s count is one lower observed band plus seven higher bands.

Different marine-band schemes. The GCR describes the lower part of its historically defined Upper Carboniferous segment as chiefly mudstone and sandy shale, with thin sandstones and nodular ironstones interpreted as brackish-marine deposits. The 1910 folding plate labels four nodular marine ironstones, Nos. 1–4. No. 1 lies with the lower plant-bed interval; pale sandstone separates it from No. 2, white fine-grained sandstone intervenes before No. 3, and black shale with coal streaks occurs between No. 3 and No. 4. The GCR discusses Nos. 2, 3 and 4 between the two Passage plant beds and warns that these are not the identically numbered bands of the Kincardine Basin. The 2025 district report separately recognises five bands at Joppa, without individually defining them there. No secure one-to-one correlation has been established between the four historical ironstones, the eight 1958 marine horizons and the later five-band count; none of these counts silently replaces the others.

Marine fossils and conodont-bearing ironstones. The 1910 appendix records the historical brachiopod Productus semireticulatus from its shore locality 205, marine ironstones in the lower third of the old Millstone Grit. Clarke’s 1953 samples G5, G4, G3 and G1, from the shaly parts of historical marine ironstones Nos. 1, 2, 3 and 4 respectively, are marked conodont-bearing. G2, shale between Nos. 3 and 4, is not marked positive. The thesis explicitly records two fragmentary Idiognathodus elements from the No. 4 shale. Its proposed new conodont names and type terminology do not, by themselves, establish formally published valid species or a verified Joppa type locality.

Plant Bed No. 1: coal and shale. In 1910 the lower plant bed was described as a 2–3 in mixture of shale and coal west of the salt pans, below the lowest nodular marine ironstone. Its appendix locality 204 records historical Lepidodendron rhodeanum and the fish Rhizodopsis sauroides, together with questioned occurrences of Lepidodendron obovatum and Sigillaria taylori. The GCR’s account of the lower plant bed gives Sphenopteris elegans, Sphenophyllum trichomatosum and Archaeocalamites radiatus. These source lists are preserved without treating them as a modern taxonomic revision. The 1958 height of about 250 ft above Castlecary, approximately 76.2 m, differs from the GCR’s about 60 m. The 1910 reference to 43 yards west of a salt-pan corner is a horizontal landmark distance, not another stratigraphical height. The same account describes this plant bed shifted laterally by two faults crossing the strike obliquely, illustrating the displacement of steeply inclined strata; it gives no numerical fault throw.

Early macrospore beds west of the salt pans. Bennie and Kidston’s 1886 locality 24 records two small coals within thick white fireclay, historically assigned to the basement Millstone Grit. The combined locality assemblage contains the numbered Triletes forms VI, VII, XII, XIV and XV, with XVIII questioned. The paper does not give the separate thickness or fossil content of each coal. The matching list reappears in the 1910 appendix at shore locality 205a with an explicit Bennie–Kidston attribution. These Roman numerals are historical macrospore morphotypes, not modern species names. The original Plate III figures 6a–6b specifically illustrate locality 24 material.

A separate early macrospore bed opposite the salt pans. Bennie and Kidston’s locality 25 is black fireclay beneath two small coals, described in separate creeks divided by a little sandstone and also assigned to the historical basement Millstone Grit. It yielded Triletes IX, including the figured material in Plate III, figure 9d. The two coal horizons remain distinct observations, but their individual measurements and relationship to the locality 24 pair are not established. This black-fireclay record cannot be merged automatically with the later white-cement-band record of the same morphotype higher in the succession.

Mottled clays and fireclays above the marine ironstones. The 1910 plate shows sandy clay with mottled red marl above No. 4, followed by mottled marl and fireclay. Higher it distinguishes bands of mottled and dark marly fireclay containing lenticular sandstone ribs, dark clayey shale, a 3 ft 8 in light-and-dark fireclay, and mottled purple and dark fireclay. The succession leads to the second plant bed. These are meaningful lithological changes, although the plate supplies no numerical thickness for most individual units.

Plant Bed No. 2: thin mineral-rich rib in black shale. The 1910 plate calls this cementstone in black shale; its appendix locality 206 describes a white cement band 1–2 in thick in the upper two-thirds of the historical Millstone Grit. The 1958 memoir instead describes a pale grey siliceous rib ½–1 in thick, about 240 ft above the lower plant bed, approximately 73.2 m. The GCR places the higher bed about 80 m above the lower one. These lithological, thickness and height descriptions remain source-specific. None justifies naming a formal limestone member.

Historical fossils of the upper plant bed. Locality 206 in the 1910 appendix carries Neuropteris sp., Sigillaria scutellata, Trigonocarpus sp. and Triletes IX, with Neuropteris heterophylla and Cordaites principalis questioned. Its white cement band and higher stratigraphical position differ from Bennie and Kidston’s black-fireclay locality 25, despite the shared Triletes IX record. The old contrast between “Lower Carboniferous” and “Upper Carboniferous” floras helped frame early correlations, but it does not precisely locate a modern global time boundary. The 1958 suggestion of a major unconformity somewhere between the plant beds was an interpretation, not a measured exposed contact.

Upper coaly shales and sandstone. Above Plant Bed No. 2 the 1910 section includes a partly concealed interval, black coaly shale with coal streaks, sandy red marl in places, and dark shale with coal streaks. These are followed by strongly cross-bedded sandstone, locally red and pebbly, and somewhat thinner-bedded sandstone immediately below Seven Foot Coal. The narrative estimates the upper major sandstone package at about 100 ft; the GCR describes the top 31 m as cross-bedded sandstone. It interprets the increasing dominance of sandstone upwards as progressive delta infilling, with river-deposited sand prominent at the top.

Thin Passage coals in the 1958 figure. The Joppa column of Figure 14 records ten thin-coal thickness labels. Read upwards, they are 1 in, 2 in, 2 in, 6 in, 8 in, 3 in, 1 in, 1 in, 5 in and 4 in. The last 4 in label lies below the separately named Seven Foot Coal datum; it is not that seam’s thickness. The figure does not supply secure numerical heights for all these coals, and its small numbers are thicknesses in inches, not marine-band identifiers. Together with the plant coals, rooted fireclays and coaly shales, they show why a blanket description of the Passage Formation as containing no coal is misleading.

SCOTTISH COAL MEASURES GROUP

Scottish Lower Coal Measures Formation: lower part

Local succession and exposure limits. These Langsettian rocks were included in the older Productive Coal Formation or Productive Coal Measures. The GCR describes about 120 m exposed at Joppa, with a lower shale-dominated division of about 58 m and a higher sandstone-dominated succession described separately as 64 m. Those rounded figures should not be treated as an exact complete log. The positions of Seven Foot, Four Foot, Fifteen Foot and Nine Foot coals were partly inferred by comparison with underground sections and fossil markers. The 1910 memoir already warned that some seam positions were doubtful; the 1958 memoir also records concealment. The named thickness of a coal is not necessarily its measured coal thickness.

Seven Foot Coal: three coal leaves. The older record repeated in 1958 gives, upwards, a 2 ft lower coal, 2 ft 6 in of fireclay, a 6 ft middle coal, 4 ft of fireclay and a 1 ft 3 in upper coal. The whole complex is 15 ft 9 in, approximately 4.80 m, of which 9 ft 3 in, approximately 2.82 m, is coal. Only the lower and upper portions could be seen when the 1958 account was prepared. The 1910 coal log also includes 1 ft 6 in of fireclay below the complex.

Plant Bed No. 3 near Seven Foot. The 1910 plate explicitly labels black shale with plants beside the probable Seven Foot Coal position. This is a third plant bed, separate from the two Passage horizons. Appendix locality 207 is only located within a few feet of the Seven Foot outcrop, rather than unequivocally in the coal or its roof. Its historical list comprises Alethopteris lonchitica, Mariopteris muricata, Annularia radiata, Lepidophloios acerosus, an indeterminate Lepidophloios, Cordaites principalis and a questioned Sphenopteris obtusiloba. The proximity record should not be sharpened into an unsupported specimen-by-specimen bed assignment.

Seven Foot to Pinkie Four Foot in the 1958 account. This interval is reported as 35 ft, mainly fakes, sandy fakes and sandy fireclay. About 12 ft above Seven Foot is a separate bed roughly 1 ft thick in which sandy ironstone alternates with thin coaly mudstones. Fish remains and mussel fragments occur in the ironstone, while inclusions of fusain and bright coal give it a breccia-like appearance. The 12 ft figure is the bed’s height above the seam, not its thickness; the rock is a sedimentary horizon.

Roof sequence above Pinkie Four Foot. The 1958 shore table starts above the seam position with more than 1 ft 5 in of fireclay and coaly fireclay. Next are 7 in of dark fakes and silty mudstone, locally capped by an irregular ironstone rib about 1 in thick with Carbonicola sp. A separate 1 in hard dark-grey sandy ironstone follows, then 1 ft 6 in of hard dark carbonaceous mudstone with fish remains. The uppermost 1 ft 6 in is soft grey mudstone, poorly bedded below, containing thin sandy ironstone ribs and historical Anthracosphaerium? and Carbonicola sp., possibly of the C. bipennis group.

Historical fish records above Four Foot. The 1910 appendix’s locality 208 specifically refers to parroty shale above Four Foot Coal on the shore east of the salt pans. It records Megalichthys hibberti, Rhizodopsis sauroides and Coelacanthus elegans. These are historical determinations from that source locality, not modern reidentifications or evidence that the named species occur in every fish-bearing bed. The 1910 plate also shows finely laminated purplish-red shale above the concealed Four Foot position, with further gaps before Fifteen Foot.

Fifteen Foot Coal and its lowest roof beds. The seam was entirely obscured in the 1958 account, which reports an earlier thickness of 12 ft 6 in, approximately 3.81 m. Its detailed roof succession starts with more than 1 ft of mudstone containing a 1 in nodular ironstone rib with Carbonicola aff. communis. Above are 4 ft of silty mudstone with thin sandy ironstone ribs and 10 ft 10 in of sandy fakes and sandstone. The fuller split seam described at Woolmet is not a Joppa measurement and is not inserted here.

The three shell-bearing beds below Nine Foot. Above those sandy beds lie, in upward order, 7 in of silty mudstone with numerous crushed shells, a separate 3 in nodular clayband ironstone with abundant Carbonicola, and 6 in of mudstone with crushed shells. The 1958 fauna is assigned jointly to these three beds: Spirorbis sp., Anthraconauta cf. subovata, A. aff. trapeziforma, Carbonicola aff. communis, additional Carbonicola, and forms intermediate between pseudorobusta and rhomboidalis, and between communis and martini. These identifications cannot be redistributed among the three beds individually. A final 5 ft 10 in package of fireclay, sandstone, fakes and mudstone lies beneath Nine Foot Coal.

The Carbonicola Bed and age interpretation. Appendix locality 209 in 1910 identifies a shore Carbonicola Bed east of the salt pans, with Carbonicola robusta, Naiadites elongata and Lepidodendron obovatum. The GCR describes the important non-marine bivalve horizon about 9 m above Fifteen Foot Coal as formerly exposed but no longer visible at the time of its account. It reports Leitch’s reinterpretation of the old C. robusta identification as part of C. communis sensu lato, indicating a middle Langsettian age. This revision is reported through the GCR; it is not a new examination of Joppa specimens or a claim that the entire intervening 9 m is fossiliferous.

Nine Foot Coal and the overlying pair of fossil bands. The historically exposed seam comprised a lower coal 5 ft 6 in thick, 2 ft of fireclay and an upper coal 1 ft 1 in thick. Thus the whole complex is 8 ft 7 in, approximately 2.62 m, while net coal is 6 ft 7 in, approximately 2.01 m. The 1958 account gives 33 ft from Nine Foot to Salters, with rapidly alternating sandstone, fakes and silty mudstone and some fireclay. About 8 ft above Nine Foot are two thin mudstone bands separated by 6 in. Their combined recorded fauna includes Spirorbis sp., Anthraconauta cf. tenuioides and other Anthraconauta; separate species lists or thicknesses for the two bands were not supplied.

Salters Coal: two coal leaves and seatearth. The 1958 historical record gives a lower 2 ft coal, a 4 ft fireclay parting and an upper 2 ft coal. The GCR describes the same three-part arrangement in rounded metric terms: two 0.6 m coals separated by 1.2 m of seatearth in the upper part of the lower, shale-rich succession. The historical gross complex is 8 ft, approximately 2.44 m, and the combined coal is 4 ft, approximately 1.22 m. The intervening rooted sediment is not coal.

Salters to Glass in the 1958 account. Approximately 60 ft of predominantly medium-grained sandstone with coarser bands separates these seams at Joppa. Glass Coal itself was reported as 3 ft 7 in thick. Above its position, the measured succession rises through 10 in of hard dark carbonaceous fakes with fish remains; 2 ft 4 in of reddish-purple mudstone with thin ferruginous ribs and occasional small non-marine bivalves; and 1 ft of reddish-purple silty mudstone with dark-red ironstone ribs. These are followed by 12 ft 9 in of fakes and sandy fakes and more than 90 ft of massive, cross-bedded sandstone with coarse bands and reddish-purple staining. The memoir states that neither Quarry Coal nor Cowpits Five Foot Coal was exposed at Joppa.

The separate 1910 coal log: Seven Foot to Fifteen Foot. The published “Brunstane Coals at Joppa” section has different interval measurements and must remain a separate historical log. Above the Seven Foot complex already described, it gives 24 ft of sandstone, 20 ft of fireclay with ironstone, 3 ft of sandstone and 6 ft of fireclay before the 4 ft Four Foot Coal. That makes 53 ft of intervening strata, compared with 35 ft in the 1958 account. Above Four Foot it records 15 ft 6 in of sandstone and shale, 8 ft of fireclay and 100 ft of red sandstone before the 12 ft 6 in Fifteen Foot Coal. These figures are retained as published, not substituted for the finer later roof-bed descriptions.

The separate 1910 coal log: Fifteen Foot upwards. Above Fifteen Foot the older log gives 31 ft of shale before Nine Foot’s lower 5 ft 6 in coal, 2 ft fireclay and upper 1 ft 1 in coal. It then records 18 ft of fireclay and 45 ft of sandstone and shale before Salters’ lower 2 ft coal, 4 ft fireclay and upper 2 ft coal. That 63 ft Nine Foot–Salters interval differs from the 1958 figure of 33 ft. Above Salters are 110 ft of sandstone and a 3 ft 7 in seam called Greymecham. The printed total from the basal fireclay beneath Seven Foot to Greymecham is 434 ft 5 in, approximately 132.41 m. The memoir itself warns that this shore log differs substantially from the neighbouring mine section.

Highest sandstones and uncertain upper coal correlation. The 1910 plate depicts brown and purple sandstone above Salters, a sandstone and purple-marl interval, red marly sandy shale with purple sandstone ribs near the probable Greymecham position, then coarse white sandstone and the highest red and purplish sandstone. The GCR separately describes 64 m of brown-to-purple cross-bedded fluvial sandstone above Salters, with a 4 m shale towards its top thought to mark the Greymechan Coal horizon. The 4 m is shale, not measured coal. The 1910 Greymecham, GCR Greymechan and 1958 Glass labels are retained in their respective accounts; matching reported coal thickness alone does not establish their equivalence.

What the sequence records. Repeated marine shell beds and limestones, river and delta sandstones, rooted soils, coal and non-marine bivalve beds preserve changing environments within a subsiding Carboniferous basin. The named limestone markers and distinctive faunas make the shore valuable for correlation, while the Passage clays, marine ironstones and plant beds show why its history cannot be reduced to sandstone alone. Fault offsets described in 1910, possible missing strata above Calmy and later exposure gaps prevent a perfectly continuous measured column. No numerical local fault throw is established by these accounts. The described succession is sedimentary; these sources do not establish a local igneous intrusion.

References

Bennie, J. and Kidston, R. (1886). On the Occurrence of Spores in the Carboniferous Formation of Scotland. Proceedings of the Royal Physical Society of Edinburgh, 9, 82–117, plates III–VI. Read 21 April 1886; the session part is dated 1886 and the completed volume 1888.

Peach, B. N. and colleagues (1910). The Geology of the Neighbourhood of Edinburgh. Memoirs of the Geological Survey, Scotland. Shore section, Plate VII; pp. 161, 245–246 and 257; Appendix B, exact shore localities 204–209, including 205a.

Clarke, W. J. (1953). Scottish Carboniferous Conodonts. PhD thesis, University of Edinburgh. Joppa Shore locality G, sample key and systematic occurrence descriptions. Historical element taxonomy and thesis nomenclature are used only with the qualifications above.

Tulloch, W. and Walton, H. S. (1958). The Geology of the Midlothian Coalfield. Memoirs of the Geological Survey, Scotland. Exact Joppa measured sections, Figure 14 and Plate IV; palaeontological discussion by R. B. Wilson.

Cleal, C. J. and Thomas, B. A. (1996). British Upper Carboniferous Stratigraphy. Geological Conservation Review Series, 11. Joppa Shore, pp. 271–274 and Figure 12.7.

Cossey, P. J. and colleagues (2004). British Lower Carboniferous Stratigraphy. Geological Conservation Review Series, 29. Joppa Shore, pp. 52–53 and Figure 2.20.

Browne, M. A. E. and colleagues (2025). Geology of the Edinburgh district. BGS Open Report OR/25/006. Foreword; Castlecary photograph, Plate 10; Passage Formation discussion, Table 8 and Figures 14–15. The report explains that most of its geology reflects understanding reached in the early 2000s.

British Geological Survey, Lexicon of Named Rock Units: Clackmannan Group, Upper Limestone Formation, Calmy Limestone, Castlecary Limestone, Passage Formation, Scottish Coal Measures Group and Scottish Lower Coal Measures Formation; consulted October 2026 for current hierarchy, ages and boundary definitions.