Redcar Fossil Hunting

1876 – A detailed Redcar reef succession
Ralph Tate and John Frederick Blake published measured descriptions of the Redcar scars and extensive fossil records in The Yorkshire Lias. Their numbered shell beds, shales and limestone horizons remain important reference points, although later work has revised the ammonite names, ages and correlations. These are reef records rather than a log of the Millclose shingle.

1878–1886 – The oldest reef ammonites illustrated
Thomas Wright’s monograph illustrated Alsatites liasicus from Redcar. Modern reassessment uses this evidence for Liasicus-age strata; the older claim for Ammonites johnstoni at Leigh-Dam Scar may involve a misidentification and does not securely establish a Planorbis-age exposure.

1906 – The structure of the foreshore recognised
R. Herries described the Redcar exposures as part of a gentle anticline. This helped explain why similar beds reappear along the coast and why separate reefs cannot simply be read as one uninterrupted shoreline section.

1971 – Ostracods revised from new samples
Alan Lord revisited Lower Lias ostracods originally described from Yorkshire in the nineteenth century. His Redcar sampling stations R 1–R 11 are mapped separately from his Hotham and Cliffe material. The revision made the microscopic fauna useful for later comparisons; its sample codes are not the Red codes used in the 2020 study.

1984 – Modern lithostratigraphic terminology
John Powell’s revision of the Yorkshire Lias Group established the modern framework used for the Redcar Mudstone Formation and its members. Subsequent work placed the Redcar scar successions within that framework, while retaining historic bed names as useful local references.

1992 – Geochemical and gamma-ray study
Van Buchem and colleagues studied the Redcar succession using a simplified measured section and gamma-ray and geochemical evidence. Their work identified an upward-coarsening trend capped by shelly sandstone with ferruginous ooids near the base of the Semicostatum interval.

2004 – A national stratigraphic synthesis
Kevin Page’s Geological Conservation Review account assembled the Redcar and Coatham reef evidence, highlighting the importance of the early Jurassic succession and the uncertainty of some older ammonite records. Its statement that modern detailed facies work was lacking was subsequently overtaken by the 2020 study.

2011 – New gastropods from the Redcar coast
Gründel, Kaim, Nützel and Little introduced the genus Lensataphrus, with Lensataphrus tatei as its type species, and also described Lensataphrus tenuis from material labelled from the coast near Redcar. L. tatei corrected an older identification as Turbo philemon. These publication localities do not identify Millclose as the collecting spot.

2018–2019 – Reefs exposed and conservation strengthened
Storm exposure in 2018 enabled a new geological survey. Redcar Rocks was also incorporated into the enlarged Teesmouth and Cleveland Coast Site of Special Scientific Interest, notified in 2018 and confirmed in 2019. The designation protects both the geological resource and wider coastal interest; it does not confer unrestricted collecting rights.

2020 – A new facies and fossil study
J. W. Atkinson, P. B. Wignall and K. N. Page published their Hettangian–Sinemurian reef study. It documented five upward-coarsening cycles, shell-bed faunas, thin-section fossils and environmental evidence. Figured ammonites, gastropods and bored bivalves were deposited at Whitby Museum, allowing the observations to be checked against real specimens.

The modern beach at Millclose Howles is a superficial shingle deposit. No measured bedrock section through this collecting stretch has been established by the sources used here. The records below describe the separately located Redcar and Coatham rock reefs northwest of the Stray. The modern log is described from lower to higher strata; the historical table retains its original top-down order and numbering. No bed assignment is made for a loose Millclose fossil.

Lias Group

Redcar Mudstone Formation

The formal formation consists mainly of fossiliferous grey mudstone and siltstone, with subordinate shelly limestone, sandstone and concretions. Its regional Hettangian–Pliensbachian age range and maximum regional thickness are not measurements of the Millclose beach. The nearby reefs expose different parts of the formation; their local detail is set out separately below.

Calcareous Shale Member: nearby Redcar Rocks

Lower modern log and covered intervals
Atkinson, Wignall and Page surveyed storm-exposed reefs in 2018. Their 2020 graphic log spans the latest Hettangian and early Sinemurian, with a plotted scale approaching 57 m rather than a continuous exposed section of that thickness. Below Red 1 are two covered stretches separated by a thin, unnumbered Gryphaea-bearing shell bed. The exposed lower mudstones include Schlotheimia-bearing levels in the lowest 9 m. Thin shell beds, concretions and intervening mudstones continue above.

Jenny Leigh’s Scar: approximately 16–22 m
The densely bedded interval contains 16 closely spaced shell beds and corresponds in the paper to Tate and Blake’s beds 66–98. Individual shell beds in the surveyed succession are no more than about 0.3 m thick. The shell concentrations are separated by mudstone and provide resistant ribs on the shore. Earlier records establish the rotiforme ammonite fauna; the 2018 survey itself did not recover ammonites from the Jenny Leigh’s shell beds. The change from Rotiforme to Bucklandi subchronozones is not precisely fixed.

Nodule-rich mudstones: approximately 24–32 m
Above Jenny Leigh’s shell-rich package, mudstone with abundant sideritic concretions and relatively few shells corresponds broadly to historical beds 55–64. Red 11 lies in the lower part; Red 12 records partly articulated crinoids; Red 13 and Red 14 are higher. The Coroniceras ex gr. multicostatum record at Red 14 suggests the late Bucklandi Subchronozone. Do not infer a fossil absence where the paper merely lacks an observation.

Approach to and beds of Stokesley Scar: approximately 32–38 m
Shell concentrations recur above the nodule-rich interval. Red 15 includes bored Cardinia; Red 16 contains the solitary coral Trocharea guettardi and Chlamys textoria. The paper correlates Red 16 with historical bed 55, the second highest of four coral-bearing beds. The principal Stokesley shell-bed cluster is about 36–38 m and is correlated broadly with historical beds 35–53. In upward order the labelled samples are Red 17, Red 26, Red 18 and Red 19. Paracoroniceras near the top signals the basal Semicostatum Chronozone.

Above Stokesley and East Scar: approximately 38–47 m
Finer sediment follows Stokesley, becoming siltier above about 40 m. At approximately 42–47 m, East Scar contains fine calcareous sandstone, compared by the authors with historical beds 32–11. Some phosphatic nodules are cigar-shaped and about 5 cm long; one at Red 24 preserves burrow mottling. Red 24 lies below Red 21 despite the numerical labels; Red 23 lies below Red 27. A covered stretch occurs above Red 28 near the top of this part of the graphic log.

Upper, discontinuously exposed interval
The middle graphic column ends near 47 m; the final column resumes at 51 m. The intervening span must not be shown as continuously logged or exposed. The final column has cover below Red 29, between Red 29 and Red 30, and between Red 30 and Red 31. Red 31 is a thin exposed cap above cover. Agassiceras and Arnioceras acuticarinatum at Red 29 and Red 30 support the Scipionanum Subchronozone. The crossed-out areas represent cover, not fossil-barren measured beds.

Five upward-coarsening cycles
The paper recognises five parasequences: the first ends at the Jenny Leigh’s shell-bed interval, the second at Stokesley Scar, and the third and fourth are developed in the East Scar succession. Only the lower part of the fifth is represented at the top. These are sedimentary cycles, not five named members, and their boundaries should not be converted into unsupported exact bed heights. Shell-rich coarse tops reflect shallowing and reworking on a marine shelf; finer intervening deposits reflect quieter conditions.

Preservation and palaeoecology
Bioturbation is widespread. Thin sections show burrow-related shell reorientation, microgastropods, ostracods and foraminifera. Glauconite replaces some echinoderm debris, and iron minerals have modified the sediment after burial. Pyrite-framboid measurements were interpreted as evidence of generally oxygenated to oxygen-poor bottom water, without demonstrated persistent anoxia. The modern paper does not support treating the whole reef succession as a stagnant, lifeless black shale or a brackish lagoon.

Internal structure of the shell beds
Within the surveyed shell beds, the basal material is muddy and contains broken shell debris. Upward, silt and sand increase and larger Gryphaea shells become prominent. Some beds culminate in biosparite, a shell-rich carbonate rock with sparry calcite cement, containing mud lenses. This is a repeated internal pattern within shell beds, not a set of additional formations.

East Scar fine-sediment package
The upward change includes relatively homogeneous siltstone passing to carbonate-cemented fine sandstone. The upper sandstone contains abundant shell debris and Gryphaea.

Pyrite-framboid size proxy
The study reports an overall mean framboid diameter of 8.35 µm, with standard deviation 4.31 µm. These are microscopic mineral-size statistics, not bed thicknesses. Red 28 contains locally developed pyrite cement; iron-oxide grains and foraminiferal infills at Red 27 and Red 29 may replace earlier siderite or pyrite, an interpretation the paper qualifies.

Other historical reef fossils
The GCR records intact Isocrinus psilonoti crowns in dark-grey micaceous siltstone in Natural History Museum collections, as discussed by Simms in 1989. It also reinterprets historical echinoids as probable Miocidaris lobatum and Diademopsis spp. and records Heterastraea excavata. Occasional marine-reptile vertebrae and teeth and Hybodus and Acrodus remains belong to the historical reef record. They are neither modern numbered samples nor identified Millclose specimens.

Historical coral-bed and microfaunal qualifications
The GCR describes a Sinemurian Montlivaltia guettardi band with Gryphaea, and a lower Angulata Coral Bed labelled 14 in its restarted historical scheme, containing varied bivalves and gastropods. This “Coral Bed 14” is not modern Red 14 and is not the continuous-numbered bed 14 transcribed above. The explicit modern Red 16–historical bed 55 correlation is a separate observation. Tate and Blake’s ostracod account included 16 named forms, including Bairdia redcarensis and Cythere redcarensis, while Lord’s revision records 13 at Redcar; these lists must not be added as independent species totals.

Historical nominal diversity
From the older Hettangian–Sinemurian boundary-bed literature, the GCR reports 44 nominal bivalve species, 26 gastropods and scaphopods combined, three brachiopods, three corals, four echinoderms, six annelids, a nautiloid and a belemnite. These are historical categories distributed through the reefs, not a current taxonomic census, one sample assemblage or a promise of finds in Millclose shingle.

Shell preservation varies between reefs
In the upper Jenny Leigh’s shell beds, Cardinia listeri is abundant alongside Gryphaea; borings are rare and articulated Cardinia shells are more common. At Stokesley and East Scar, Cardinia and Gryphaea frequently show borings filled with sediment from the Jurassic matrix. The contrasts concern the reef assemblages, not the condition expected of every loose Millclose shell.

Figured Red 15 museum specimens
The figured Red 15 Cardinia listeri series is catalogued in the source as WHITM 2020/1.4–8 in Whitby Museum. The interpretation of their borings and growth irregularity remains uncertain.

Modern sample register: Red codes
The following observations belong to the 2018 reef survey published in 2020. Codes are in plotted stratigraphic order, not numerical order. They are sampling labels, not bed numbers; Red 25 is not plotted. Fossil symbols without a named identification are left unnamed. The figured specimens with WHITM numbers are held by Whitby Museum. None of these sample labels applies to a loose Millclose find.

Red 1
Schlotheimia sp.; figured specimen WHITM 2020/1.1.

Red 2
Glomospirella; ostracods; microgastropod in thin section.

Red 3
Ostracods.

Red 4
Gryphaea-bearing shell-bed sample on the graphic log.

Red 5
Ammonite-bearing mudstone level on the graphic log.

Red 6
Shell-bed biosparite illustrated in thin section.

Red 7
Logged mudstone sample, with pyrite-framboid analysis.

Red 8
Serpulid tube nests; glauconite-replaced echinoderm fragments in shell bed.

Red 9
Glauconite-replaced echinoderm fragments in shell bed.

Red 10
Logged near the top of the Jenny Leigh’s Scar interval. An adjacent graphic ammonite symbol is not a documented 2018 ammonite collection from the scar; the authors report none from Jenny Leigh’s shell beds in that survey.

Red 11
Silty mudstone with abundant diagenetic ankerite grains.

Red 12
Partly articulated Isocrinus psilonoti with cirri; photographed in situ.

Red 13
Ammonite symbol beside a carbonate-concretion-bearing horizon in the graphic log.

Red 14
Coroniceras ex gr. multicostatum, suggesting the late Bucklandi Subchronozone.

Red 15
Bored Cardinia listeri, including possible Simonizapfes and possible bryozoan borings; growth irregularity; ostracods; glauconitic echinoderm fragments; illustrated framboids.

Red 16
Trocharea guettardi and Chlamys textoria; equivalent to Tate and Blake bed 55, the second highest of their four coral-bearing levels.

Red 17
Pleurotomaria cognata, WHITM 2020/1.3; glauconite-replaced echinoderm fragments.

Red 26
Shell-bed sample within the Stokesley Scar cluster, between Red 17 and Red 18 in stratigraphic order.

Red 18
Shell-bed sample in the Stokesley Scar cluster.

Red 19
Gryphaea-rich shell bed photographed at outcrop.

Red 20
Ostracods.

Red 24
Phosphatic nodule preserving burrow mottling; ostracods.

Red 21
Arnioceras sp. encrusted by Liostrea irregularis, WHITM 2020/1.2.

Red 22
Fine-grained interval below the stronger sandy/shelly East Scar beds; analysed for framboids.

Red 23
Mudstone thin section showing a shell fragment rotated by burrowing.

Red 27
Numerous Lenticulina; iron oxide grains and foraminiferal-test infills.

Red 28
Shell bed with locally developed pyrite cement; Gryphaea shell with simple boring.

Red 29
Agassiceras and Arnioceras acuticarinatum in the Scipionanum Subchronozone; iron oxide grains and foraminiferal-test infills.

Red 30
Agassiceras and Arnioceras acuticarinatum in the Scipionanum Subchronozone.

Red 31
Highest labelled sample on graphic log; separated from underlying exposed interval by cover.

Observed fossils in the modern range chart
Figure 8 plots 38 taxon or component columns, including open identifications and debris; this is not a list of 38 securely identified species. Black circles record field observations and shaded squares record thin-section-only observations. The connecting and extending lines also draw on records outside this particular Redcar survey, so they are not additional local finds. The approximate positions below are read from that graphic, rounded to about half a metre; they are not new thickness measurements, exact collection stations or assignments to Red sample codes. Close symbols may merge at this resolution; duplicate rounded values are collapsed without implying fewer specimens.

Gryphaea arcuata
Field observations plotted at approximately 2, 4, 6.5, 7, 9, 11, 12, 12.5, 14.5, 15.5, 16.5, 17.5, 18.5, 19, 19.5, 28, 30, 34, 35, 40.5, 43, 43.5, 45.5, 46.5, 51.5, 54, 56.5 m. Multiple closely overlapping black circles additionally occupy c.20.3–22.6 m and c.36.2–37.9 m; these are observed-marker clusters, not inferred continuous occurrences. Three close circles at c.11.9–12.5 m are also directly visible.

indeterminate protobranch
Field observations plotted at approximately 5.5, 38 m.

Ophiuroid
Thin-section-only observations plotted at approximately 6.5, 7, 25.5 m. All plotted symbols are thin-section squares.

Echinoderm debris
Field observations plotted at approximately 25.5, 34.5, 37.5, 51.5 m. Thin-section-only observations plotted at approximately 6.5, 11, 15.5, 21, 34, 36, 43, 45.5 m. Mixed field circles and thin-section-only squares. The markers include fragments rather than necessarily whole identifiable animals.

Plagiostoma giganteum
Field observations plotted at approximately 7, 37, 37.5, 40.5, 42.5, 43, 54 m.

Pseudolimea pectinoides
Field observations plotted at approximately 7, 15, 18.5, 21, 22.5, 24, 28, 32, 34, 43.5, 54 m. Thin-section-only observations plotted at approximately 43 m.

Pinna sp.
Field observations plotted at approximately 7 m. Thin-section-only observations plotted at approximately 34 m.

Isocrinus psilonoti
Field observations plotted at approximately 8, 28, 31, 36, 37.5 m. Fig 7 E and text separately identify partially articulated material with cirri in Red 12.

Atreta intusstriata
Field observations plotted at approximately 8, 9 m.

Luciniola limbata
Field observations plotted at approximately 9, 31, 36, 37.5, 38, 40.5, 41.5, 42.5, 43, 51.5 m.

Eucycloscala sp.
Field observations plotted at approximately 10 m.

Serpula sp.
Field observations plotted at approximately 10, 36 m. Thin-section-only observations plotted at approximately 15.5, 34 m. Atkinson’s text refers more broadly to several serpulid species; the range chart column is Serpula sp.

indeterminate gastropods
Field observations plotted at approximately 18.5 m. Thin-section-only observations plotted at approximately 11, 15.5, 21, 40.5, 43, 45.5, 51.5 m. Fig 7 D explicitly shows a Red 2 thin-section microgastropod, an occurrence not reproduced at that height in Fig 8; the caption and range chart differ.

Camptonectes cf. auritus
Field observations plotted at approximately 15, 21, 22.5, 38, 43, 54 m. The identification remains qualified by cf.

Modiolus sp.
Field observations plotted at approximately 15, 25.5, 32, 34.5, 37.5, 42.5, 45.5, 51.5 m.

Gresslya sp.
Field observations plotted at approximately 15 m.

Gervillia hagenowi
Field observations plotted at approximately 15 m. Fig 8 uses Gervillia hagenowi; Table 1 uses Cuneigervillia hagenowi. These names are not counted as two separate species here.

Plagiostoma punctatum
Field observations plotted at approximately 15 m.

Pleuromya striatula
Field observations plotted at approximately 15, 24 m.

Entolium lunare
Field observations plotted at approximately 15 m.

Cardinia listeri
Field observations plotted at approximately 21, 34, 36, 37.5, 38, 40.5, 54 m. Table 1 misspells listeria; text and Fig 7 consistently support listeri. Fig 7 F–L provides specimen-specific Red 15 records.

Calcirhynchia calcaria
Field observations plotted at approximately 21, 22.5, 28, 34, 35, 40.5 m. Brachiopod, so absent from the bivalve-only ecology Table 1.

Protocardia philippianum
Field observations plotted at approximately 24.5, 37.5, 46.5, 54 m.

Antiquilima succincta
Field observations plotted at approximately 24 m.

Ryderia doris
Field observations plotted at approximately 25.5, 54 m.

Dacryomya heberti
Field observations plotted at approximately 25.5, 31, 37.5 m.

Palaeonucula navis
Field observations plotted at approximately 25.5, 38 m.

Neocrassina sp.
Field observations plotted at approximately 25.5 m.

Terquemia difformis
Field observations plotted at approximately 28 m.

Oxytoma inequivalvis
Field observations plotted at approximately 31, 32, 34, 35, 36.5, 37.5, 38, 39.5, 42.5, 43, 45.5, 46.5 m.

Chlamys textoria
Field observations plotted at approximately 35, 36, 40.5, 42.5, 45.5, 46.5 m. Thin-section-only observations plotted at approximately 34 m.

Trocharea guettardi
Field observations plotted at approximately 35 m. The text explicitly associates Red 16 with Tate–Blake Bed 55, second highest of four historic coral-bearing levels.

Pleurotomaria cognata
Field observations plotted at approximately 36 m. Fig 7 C explicitly identifies Red 17 specimen WHITM 2020/1.3.

Liostrea irregularis
Field observations plotted at approximately 36 m. Important discrepancy: Fig 8 single point c.36.2 m; Fig 7 B explicitly has Arnioceras encrusted by L. irregularis at Red 21 (~40.7 m on Fig 3). The two source observations remain separate.

Dentalina sp.
Field observations plotted at approximately 37.5 m. Source’s Fig 8 symbol is a black circle even though surrounding text explains foraminiferal work in thin sections. The literal marker type is reported here, without implying a macrofossil observation.

Rollieria bronni
Field observations plotted at approximately 38, 41.5, 46.5 m.

Palaeoneilo elliptica
Field observations plotted at approximately 38, 41.5, 42.5 m.

Grammatodon (Cosmetodon) sp.
Field observations plotted at approximately 43 m.

Additional modern observations and source limits
The paper also records large fossilised logs and the foraminifera Pseudonodosaria, Paralingula and Dentalina without giving a Red sample number for each. Figure 7 B assigns the Liostrea irregularis-encrusted Arnioceras specimen to Red 21, whereas the range-chart Liostrea observation is drawn at a lower plotted position; these records are left separate. Figure 7 D documents a Red 2 microgastropod that is not marked at that position in Figure 8. Potential Simonizapfes borings, possible bryozoan borings and suggested overcrowding damage on Cardinia remain qualified interpretations. Gervillia hagenowi in Figure 8 and Cuneigervillia hagenowi in Table 1 are not counted as two separate taxa.

Lord’s 1971 ostracod samples: R 1–R 11
These are a separate historical sampling scheme from the Redcar foreshore scars. R 1–R 4 were assigned to the angulata-zone beds south of Jenny Leigh’s Scar; R 5–R 11 came from bucklandi-zone beds or higher. Those are Lord’s historical age terms, not established equivalences to the 2020 sample codes. Thirteen of the 17 taxa in the combined Redcar–Hotham–Cliffe study have Redcar records. No taxon is marked for R 1 in the distribution table; a blank is not proof that the original sediment lacked fossils.

Polycope cerasia Blake 1876
Reported Redcar samples: R 4, R 5, R 8, R 11. Plate 122 figs 1–2: HU.52.J.2, Redcar R 5.

Cytherella drexlerae Field 1967
Reported Redcar samples: R 6, R 9, R 11. The text distribution and chart differ. The distribution text lists R 6, R 9 and R 11, but text-figure 4 marks only R 9; the discrepancy is unresolved.

Cytherella concentrica Field 1966
Reported Redcar samples: R 6, R 8, R 10, R 11. Plate 122 figs 3–4: HU.52.J.3, Redcar R 10.

Cytherelloidea circumscripta (Blake 1876)
Reported Redcar samples: R 2, R 5, R 10, R 11. Plate 122 figured specimen is South Cliffe pit b, not Redcar.

Cytherelloidea pulchella Apostolescu 1959
Reported Redcar samples: R 2. Plate 122 figured specimens are North Cliffe pit a, not Redcar.

Bairdia cf. B. carinata Drexler 1958
Reported Redcar samples: R 11. The identification is qualified by cf.; Plate 122 fig 13 HU.52.J.13 is Redcar R 11.

Bairdia tatei Coryell 1963
Reported Redcar samples: R 4, R 5, R 8. Plate 122 figs 14–15 HU.52.J.15 is Redcar R 8.

Paracypris cf. P.? semidisca Drexler 1958
Reported Redcar samples: R 8. Both the comparison and its taxonomic name are uncertain.

Klinglerella aff. K. triebeli (Klingler and Neuweiler 1959)
Reported Redcar samples: R 6. The identification is qualified by aff.; figured Plate 123 material is South Cliffe pit b. Lord notes Redcar material is more inflated and may not belong to the same taxon as Cliffe material (p 656).

Klinglerella? translucens (Blake 1876)
Reported Redcar samples: R 6. The genus attribution is uncertain; Plate 123 figs 4–5 HU.52.J.22–23 are Redcar R 6.

Ogmoconcha ellipsoidea (Jones 1872)
Reported Redcar samples: R 4, R 8, R 9, R 11. Systematic heading p 658; distribution p 659. Plate 123 figured material is from Cliffe/Hotham pits, not Redcar.

Ogmoconcha hagenowi Drexler 1958
Reported Redcar samples: R 2, R 3, R 4, R 5, R 7, R 8, R 9, R 10, R 11. Plate 123 figs 14–16 from Redcar R 9 (HU.52.J.50,49) and R 8 (HU.52.J.44).

Ogmoconcha sp. A
Reported Redcar samples: R 6, R 7, R 11. Plate 123 figs 17–18 HU.52.J.55,53 from Redcar R 6. Possible relation to O. caudata discussed tentatively on p 663; the relationship remains tentative.

Older microfaunal context
Lord found foraminifera, ostracods and microgastropods in the Redcar residues; R 7 was almost entirely microgastropods. His suggestion of intermittent brackish influence was tentative and is not a demonstrated salinity for the whole reef succession. Abundant holothurian spicules in his account belong to the separate Hotham/Cliffe samples. Bairdia aff. B. molesta, Bairdiacypris?sartriensis, Klinglerella moorei and “Cythere” terquemiana from those other areas are not added to the Redcar list. The species names and uncertain identifications above are reported as used in 1971, without claiming a modern taxonomic revision.

Gastropods published in 2011: broader Redcar-coast provenance
Gründel and colleagues studied Manfred Jäger’s bulk-collected material from the coast near Redcar, with no bed-by-bed collection positions. Their records include Colpomphalus angulatus, Eucycloscala?sp., Lensataphrus tatei, L. tenuis, Kosmopleura hoelderi, Cryptaulax (spelled abcisum in the systematic account), Levipleura sp., Tricarilda sp. 1 with a separately qualified cf. sp. 1 juvenile, and Cylindrobullina avena. These must not be placed at Millclose or equated to Lord’s or Atkinson’s individual samples.

Type specimens and a corrected old identification
Lensataphrus tatei, the type species of the new genus Lensataphrus, has holotype MG 1396 and paratype MG 1397; L. tenuis has holotype MG 1399. The locality is the coast near Redcar and the horizon is broadly Hettangian–early Sinemurian. Tate’s 1876 specimen identified as Turbo philemon was referred to L. tatei in this revision. The authors state that illustrated material was deposited at the Natural History Museum, London. Their separate West Cliff, Ilminster, Henley, Jet Wyke and Port Mulgrave records are not imported here.

Independent historical scheme: Tate and Blake, 1876
The following top-down record preserves the original numbered packages from pp. 48–49 and 58–62. These are nineteenth-century lithological and fossil identifications, not an assertion that every old species name is currently accepted. “Ammonites” was then used much more broadly. The original Upper, Middle and Lower Bucklandi subdivisions do not map one-to-one to today’s ammonite chronozones. Shared thickness braces remain shared; measurements have not been divided among beds or added to the modern log. Historical bed 1 is the separate younger High Stone exposure. Bed 102 is a tie-point repeated at the top of the angulatus table, not two different beds. The GCR’s later renumbered Angulata scheme and Lord’s R samples are also distinct.

Historical bed 1 — 23 ft 6 in
Calcareous shale, unseen; High Stone reef. Historical fossil record: Ammonites-oxynotus beds.

Historical bed 2 — 10 ft
Calcareous shale. Historical fossil record: Ammonites semicostatus; Gryphaea arcuata.

Historical bed 3 — 8 ft
Calcareous shale. Historical fossil record: No separate fauna entered.

Historical bed 4 — 1 ft
Calcareous shale with limestone nodules and oyster bed. Historical fossil record: A. semicostatus; Pecten calvus; P. Thiollieri; Monotis inaequivalvis; G. arcuata.

Historical bed 5 — 4 ft
Calcareous and friable shale. Historical fossil record: A. Turneri; P. Thiollieri; G. arcuata.

Historical bed 6 — 4 ft
Indurated grey shale. Historical fossil record: No separate fauna entered.

Historical bed 7–8 — 16 ft 6 in combined
Soft blue shale with black limestone nodules at base; friable sandy shale. Historical fossil record: A. Turneri; A. bisulcatus; Belemnites infundibulum; Cardinia Listeri and var. hybrida; C. concinna; Lima gigantea; L. succincta; Hippopodium; Pleuromya galathea; Monotis inaequivalvis; Pecten textorius; Gryphaea arcuata.

Historical bed 9 — 3 ft 6 in
Indurated shale. Historical fossil record: A. Turneri; A. bisulcatus; Lima gigantea; Cardinia Listeri.

Historical bed 10 — 11 ft
Smooth blue shale with small cylindrical black limestone nodules; The Flashes. Historical fossil record: A. bisulcatus; small A. Scipionanus.

Historical bed 11–12 — 3 ft 9 in combined
Friable shale with black limestone nodules; hard calcareous shale and oyster band; top scars of East Scar. Historical fossil record: Ichthyosaurus; Acrodus nobilis; A. Bucklandi; A. Sauzeanus; Belemnites acutus; Gervillia Hagenovii; Cardinia Listeri; Spiriferina Walcotti.

Historical bed 13 — 1 ft 3 in
Oyster band and earthy limestone. Historical fossil record: No separate fauna entered.

Historical bed 14 — 1 ft 9 in
Calcareous shale with nodules; main East Scar. Historical fossil record: A. Bucklandi; common large A. Sauzeanus; Monotis inaequivalvis.

Historical bed 15 — 6 in
Soft shale. Historical fossil record: A. Sauzeanus, fauna bracket shared with 16.

Historical bed 16 — 8 in
Limestone. Historical fossil record: A. Sauzeanus, fauna bracket shared with 15.

Historical bed 17–19 — 11 in combined
Oyster band; shaly limestone; hard calcareous shale. Historical fossil record: No separate fauna entered.

Historical bed 20 — 1 ft
Friable shale. Historical fossil record: No separate fauna entered.

Historical bed 21 — 3 in
Oyster bank. Historical fossil record: No separate fauna entered.

Historical bed 22 — 4 in
Hard shale with black limestone nodules. Historical fossil record: No separate fauna entered.

Historical bed 23 — 10 in
Friable shale. Historical fossil record: No separate fauna entered.

Historical bed 24 — 1 ft 10 in
Shale. Historical fossil record: No separate fauna entered.

Historical bed 25 — 6 in
Limestone. Historical fossil record: No separate fauna entered.

Historical bed 26 — 5 in
Soft shale. Historical fossil record: No separate fauna entered.

Historical bed 27 — half inch
Oyster band. Historical fossil record: Gryphaea arcuata.

Historical bed 28 — 8 in
Soft shale. Historical fossil record: No separate fauna entered.

Historical bed 29 — 10 in
Shale with nodules. Historical fossil record: No separate fauna entered.

Historical bed 30 — 1.5 in
Limestone. Historical fossil record: A. Bucklandi; G. arcuata.

Historical bed 31 — 3 ft 6 in
Hard shale. Historical fossil record: No separate fauna entered.

Historical bed 32 — 9 in
Earthy limestone mixed with shale. Historical fossil record: No separate fauna entered.

Historical bed 33 — 3 ft
Friable shale; lowest East Scar ridge. Historical fossil record: A. bisulcatus.

Historical bed 34 — 12 ft
Soft shale. Historical fossil record: A. bisulcatus; A. Charmassei; large Cardinia concinna.

Historical bed 35–40 — 9 ft combined
Three one-inch oyster beds (35,37,39), alternating with soft shale (36 nodular, 38) and stiff blue shale (40). Historical fossil record: G. arcuata; Lucina limbata; Hippopodium; Myoconcha; Pecten textorius; small Cardinia concinna (fauna entered beside upper part of package).

Historical bed 41 — 3 in
Oyster bed in friable shale; Low Scar. Historical fossil record: G. arcuata; Monotis inaequivalvis; Cardinia hybrida; Hippopodium; Macrodon hettangiensis; Mytilus hillanoides; Cidaris Edwardsi.

Historical bed 42 — 1 ft
Stiff blue shale. Historical fossil record: Monotis; Mytilus hillanoides.

Historical bed 43 — 2 in
Shale with black limestone nodules. Historical fossil record: No separate fauna entered.

Historical bed 44 — 3 in
Cardinia bank; Stokesley Scar surface. Historical fossil record: Dense Cardinia Listeri and var. hybrida; Unicardium cardioides; G. arcuata.

Historical bed 45 — 7 in
Friable shale. Historical fossil record: Eucyclus elegans; Lima pectinoides.

Historical bed 46 — 4 in
Friable shale and oyster bed. Historical fossil record: No separate fauna entered.

Historical bed 47 — 8 in
Friable shale and oyster bed. Historical fossil record: Dentalium etalense; Lima gigantea; Cardinia Listeri.

Historical bed 48 — 6 in
Friable shale and oyster bed. Historical fossil record: Lima gigantea; Cardinia Listeri; Pentacrinus tuberculatus.

Historical bed 49 — 8 in
Friable shale with nodules and oyster bed; Stokesley Scar. Historical fossil record: A. bisulcatus; A. Charmassei; Eucyclus elegans; Pleurotomaria similis; P. concava; Turbo solarium; T. Philemon; Pitonellus; Cryptaenia; Turritella Dunkeri; Actaeonina fragilis; Dentalium etalense; Myoconcha; Monotis inaequivalvis; Lucina; Leda; Macrodon navicula; Unicardium; Cardinia Listeri; Modiola hillanoides; M. bifasciata; Cardia; Protocardium; Lima gigantea; L. pectinoides; Pecten textorius; Gryphaea arcuata; Rhynchonella plicatissima (var.); Ditrypa antiquata; Pentacrinus; Montlivaltia Guettardi; M. Haimei.

Historical bed 50 — 4 in
Friable shale and oyster bed. Historical fossil record: Cardinia Listeri; Lima pectinoides; Pecten textorius; Pentacrinus.

Historical bed 51 — 1 in
Oyster bank. Historical fossil record: Lima pectinoides; Pecten textorius; Pentacrinus; Cryptaenia solarioides.

Historical bed 52 — 9 in
Stiff blue shale. Historical fossil record: No separate fauna entered.

Historical bed 53 — 1.5 in
Line of blue limestone nodules; base Stokesley Scar. Historical fossil record: No separate fauna entered.

Historical bed 54 — 7 ft
Stiff blue shale with flat blue limestone nodules. Historical fossil record: Cardinia concinna.

Historical bed 55 — 1.5 in
Friable shale with oyster bed. Historical fossil record: Pecten textorius; Montlivaltia Guettardi.

Historical bed 56 — 5 ft
Stiff blue shale. Historical fossil record: A. Birchii.

Historical bed 57–58 — 2 in combined
Oyster band; friable shale with depressed limestone nodules. Historical fossil record: G. arcuata; Cardinia Listeri; Unicardium; Modiola hillanoides; Pecten textorius; Rhynchonella plicatissima (var.); A. Charmassei.

Historical bed 59 — 17 ft
Stiff blue shale. Historical fossil record: Nautilus striatus; Pleuromya crassa; Pentacrinus tuberculatus on driftwood.

Historical bed 60 — 9 ft
Thin calcareous sandstone and stiff blue shale. Historical fossil record: No separate fauna entered.

Historical bed 61 — 4.5 in
Oyster band 1 in, shale 3 in and calcareous sandstone half inch. Historical fossil record: No separate fauna entered.

Historical bed 62 — 14 ft
Stiff blue shale. Historical fossil record: No separate fauna entered.

Historical bed 63 — 3 ft 2 in
Friable shale with indurated top. Historical fossil record: No separate fauna entered.

Historical bed 64 — 2 in
Earthy limestone nodules. Historical fossil record: No separate fauna entered.

Historical bed 65 — 11.5 in
Friable shale; low-water scar west of Jenny Leigh’s main ridge. Historical fossil record: Rissoa nana; Turbo solarium; T. philemon; Discohelix semistriatus; D. Oppeli; Dentalium etalense; D. limatulum; Macrodon navicula; M. pulla; Leda galathea; L. texturata; Nucula navis; Astarte obsoleta; Tancredia ovata; Monotis papyria.

Historical bed 66 — 3 in
Lumpy limestone; low scar. Historical fossil record: A. bisulcatus.

Historical bed 67 — 1 in
Friable shale. Historical fossil record: No separate fauna entered.

Historical bed 68 — 2 in
Soft shale. Historical fossil record: No separate fauna entered.

Historical bed 69 — 2 in
Nodular limestone. Historical fossil record: A. Bucklandi; G. arcuata.

Historical bed 70 — 4 in
Shale. Historical fossil record: No separate fauna entered.

Historical bed 71 — 3 in
Gryphite limestone; scar. Historical fossil record: A. Bucklandi; Cryptaenia; G. arcuata.

Historical bed 72 — 6 in
Soft shale. Historical fossil record: No separate fauna entered.

Historical bed 73 — 2.5 in
Limestone; Jenny Leigh’s main ridge. Historical fossil record: A. Bucklandi.

Historical bed 74 — 6 in
Shale. Historical fossil record: No separate fauna entered.

Historical bed 75 — 7 in
Gryphite limestone. Historical fossil record: No separate fauna entered.

Historical bed 76 — 2 in
Shale. Historical fossil record: No separate fauna entered.

Historical bed 77 — 1 ft
Limestone. Historical fossil record: No separate fauna entered.

Historical bed 78 — 2 in
Shale. Historical fossil record: No separate fauna entered.

Historical bed 79 — 3 in
Limestone. Historical fossil record: No separate fauna entered.

Historical bed 80 — 1 in
Soft shale. Historical fossil record: No separate fauna entered.

Historical bed 81 — 3.5 in
Limestone mixed with shale. Historical fossil record: No separate fauna entered.

Historical bed 82 — 1 in
Soft shale. Historical fossil record: No separate fauna entered.

Historical bed 83 — 3 in
Lumpy limestone. Historical fossil record: No separate fauna entered.

Historical bed 84 — 6 in
Friable shale with oysters; scar. Historical fossil record: Oysters recorded lithologically.

Historical bed 85 — 3 in
Nodular limestone. Historical fossil record: No separate fauna entered.

Historical bed 86 — 5 in
Soft shale. Historical fossil record: No separate fauna entered.

Historical bed 87 — 8 in
Limestone mixed with shale; scar. Historical fossil record: A. Conybeari.

Historical bed 88 — 4 in
Soft shale. Historical fossil record: No separate fauna entered.

Historical bed 89 — 8 in
Friable shale and stone; scar. Historical fossil record: Pleurotomaria similis; Eucyclus elegans; Lima gigantea; L. pectinoides; Myoconcha; Lucina; Hippopodium; G. arcuata.

Historical bed 90 — 9 in
Soft shale; scar. Historical fossil record: Plicatula liasina; Galeolaria socialis; Cidaris; Pentacrinus; A. bisulcatus.

Historical bed 91 — 3 in
Friable shale and limestone. Historical fossil record: No separate fauna entered.

Historical bed 92 — 1 ft 1 in
Soft shale. Historical fossil record: No separate fauna entered.

Historical bed 93 — 2 in
Friable shale with stony portions. Historical fossil record: No separate fauna entered.

Historical bed 94 — 2 in
Soft shale. Historical fossil record: No separate fauna entered.

Historical bed 95 — 4 in
Limestone. Historical fossil record: No separate fauna entered.

Historical bed 96 — 4 in
Friable shale with limestone; scar. Historical fossil record: No separate fauna entered.

Historical bed 97 — 9 in
Soft shale. Historical fossil record: No separate fauna entered.

Historical bed 98 — 3.5 in
Limestone 1.5 in plus lumpy limestone 2 in; scar. Historical fossil record: Nautilus striatus; Astarte obsoleta; Leda galathea; Pinna Hartmanni.

Historical bed 99 — 1 ft 6 in
Soft shale. Historical fossil record: No separate fauna entered.

Historical bed 100 — 5 in
Soft and friable shale. Historical fossil record: No separate fauna entered.

Historical bed 101–102 — 6 in combined
Shell limestone and friable shale; line of limestone nodules above shale of angulatus zone; lowest Jenny Leigh ridge. Historical fossil record: A. Bucklandi; A. Conybeari; Pleurotomaria similis; Eucyclus elegans; Cryptaenia solarioides; Astarte obsoleta; Ditrypa globiceps; Galeolaria socialis. The p 48 tie-point 102 additionally lists Lima gigantea and Pentacrinus.

Historical bed 103 — 2 ft 8 in
Blue shale, line of A. Conybeari one foot below top. Historical fossil record: Cardinia Listeri; G. arcuata; Lucina limbata; Pentacrinus.

Historical bed 104–105 — 2 ft 6 in combined
Indurated shale 5 in and earthy limestone 1 in, then blue shale. Historical fossil record: A. angulatus; small Gryphaea; Unicardium cardioides (104); A. angulatus (105).

Historical bed 106 — 7 in
Friable shale, oyster band, irregular limestone nodules 1.5 in. Historical fossil record: A. angulatus; Pleurotomaria similis; Dentalium etalense; Astarte Oppeli; Lima gigantea; Cardinia Listeri; Pleuromya crassa; Serpula socialis.

Historical bed 107 — 1 ft
Blue shale. Historical fossil record: Large A. angulatus; scattered Gryphaea.

Historical bed 108–109 — 5 in combined
Friable shale with oysters chiefly in 2 in, then blue shale. Historical fossil record: A. angulatus; Cardita Heberti; Lucina limbata; Plicatula liasina; Terquemia arietis; Perna infraliasica; Rhynchonella plicatissima; Montlivaltia polymorpha.

Historical bed 110–111 — 3 ft combined
Small Gryphaea band half inch, then blue shale. Historical fossil record: A. angulatus; Plicatula liasina.

Historical bed 112–113 — 6 ft 4 in combined
Shell band and shelly limestone 1.5 in; blue shale with irregular doggers 5 in; then blue shale. Historical fossil record: A. angulatus; Eucyclus elegans; Astarte obsoleta (112); A. angulatus; Eucyclus acuminatus (113).

Historical bed 114–115 — 2 ft 8 in combined
Shelly, sometimes crinoidal limestone mixed with shale 2.5 in, then blue shale. Historical fossil record: Crinoids recorded lithologically.

Historical bed 116–118 — 2 ft combined, bracket continues across pages
Coral bed: very fossiliferous friable shale with pebble-like concretions 2.5 in; depressed irregular limestone doggers 1.5 in; shale with scattered medium Gryphaea arcuata. Historical fossil record: A. angulatus; Astarte Oppeli; Cardita Heberti; Plicatula liasina; Pleurotomaria similis; Montlivaltia Haimei; Serpula socialis; Waldheimia sarthacensis (116); large A. angulatus (118).

Historical bed 119–120 — 1 ft 2 in combined
Earthy subcrystalline limestone 1 in, then black smooth shale. Historical fossil record: Large A. angulatus.

Historical bed 121 — 6 in
Friable shale and oyster band. Historical fossil record: No separate fauna entered.

Historical bed 122–124 — 6 in combined
Smooth shale; siliceous limestone half inch; smooth shale. Historical fossil record: No separate fauna entered.

Historical bed 125–126 — 3 ft 2 in combined
Irregular depressed limestone doggers, thin shell limestone, friable shale, smooth shale 9 in. Historical fossil record: Large Lima gigantea (125); very large A. angulatus (126).

Historical bed 127 — 2 in
Earthy limestone or doggers. Historical fossil record: Cardinia ovalis.

Historical bed 128 — 1 ft
Smooth shale. Historical fossil record: No separate fauna entered.

Historical bed 129 — 1 in
Blue siliceous limestone. Historical fossil record: Ostrea ungula; Dentalium etalense.

Historical bed 130 — 8 in
Friable shale; disturbed north-west-dipping package 130–132. Historical fossil record: A. angulatus recorded lithologically.

Historical bed 131 — 2 in
Siliceous limestone, depressed doggers fused together. Historical fossil record: No separate fauna entered.

Historical bed 132 — 1 ft 5 in
Friable shale. Historical fossil record: A. angulatus recorded lithologically.

Historical bed 133–137 — At most 3 ft combined, source estimate
Friable shale; one-inch oyster band; depressed limestone doggers; blue shale; half-inch siliceous limestone. Low dip across 47-ft outcrop width. Historical fossil record: No separate fauna entered.

Unnumbered below 137 — 8 in limestone, plus associated 3 in shale
After 270 yards covered by boulder clay: hard grey subcrystalline limestone with white calcite, sharply disturbed against fault. Historical fossil record: Associated friable shale full of Cardinia ovalis; text also lists A. angulatus, Astarte cingulata, Nucula navis, Lima gigantea, Macrodon hettangiensis, Modiola laevis, Hemipedina Tomesi in Cardinia shale; limestone A. Johnstoni, A. angulatus, C. ovalis, L. gigantea, L. pectinoides, Pecten textilis, Cidaris Edwardsi, Nautilus striatus.

Leigh-Dam Scar — About 3 ft total; about 1.5 ft above lowest spring tides
Bluish compact limestone; calcareous shale; earthy limestone; calcareous shale. Historical fossil record: See modern reassessment: old A. Johnstoni record cannot establish a Planorbis-zone occurrence.

Historical summary: Structure and total
Calcite veins and many small faults; most faults cross strike at a large angle but some nearly parallel it. Dip W of N rises from 6° lower to 10–11° upper; 1,020-ft true-dip outcrop width gives historical calculated 180-ft succession. These are independent historical estimates, not modern log values.

Historical summary: Lower series
East Flashes and Jenny Leigh’s Scar: black crumbling shales capped by doggers and thin earthy/shell limestones, 19-ft thickness from 160-ft outcrop width. Historical taxa: Ammonites Conybeari; Eucyclus elegans; Rissoa nana; Turbo philemon; Discohelix Oppeli; D. striata; Monotis papyria; Tancredia ovata; Plicatula liasina; Rhynchonella plicatissima; Montlivaltia Haimei; Galeolaria socialis.

Historical summary: Middle series
Soft blue shale and small limestone-nodule rows, with friable shale and shell bands toward top; 93-ft estimated thickness from 530-ft outcrop width. Four separately reported shell-bank associations: Gryphaea arcuata with Montlivaltia Guettardi; Hippopodium ponderosum with Cardinia concinna and Lucina limbata; Cardinia Listeri with Unicardium cardioides; oysters alone. One Cardinia concinna bank has specimens 2–2¼ inches long, whereas specimens 4–5 inches long occur 2½ inches above in overlying shale. Shell sizes are not bed thicknesses; the authors’ single-generation/survivor sedimentation interpretation is historical, not a measured sedimentation rate. Historical taxa: Soft shales: Ammonites bisulcatus; A. Charmassei; Lima gigantea; Pleuromya . Middle-series characteristic list: Ammonites bisulcatus; A. Charmassei; Cryptaenia solarioides; Turbo solarium; Cerithium gratum; Turritella Dunkeri; Hippopodium ponderosum; Unicardium cardioides; Cardinia concinna; C. crassiuscula; Pecten textorius; Montlivaltia Guettardi.

Historical summary: Upper series
Earthy limestone and calcareous shale, purely argillaceous strata less than half; 66-ft estimated thickness from 340-ft outcrop width; East Scar and narrow seaward scars. Diversity declines upward. End-of-series assemblage and whole-series characteristic list are different scopes. Historical taxa: Highest declining assemblage: Cardinia Listeri; Gryphaea arcuata; Lima gigantea; L. pectinoides; Monotis inaequivalvis; Belemnites acutus; Ammonites Turneri. Whole-upper-series list: Ammonites Turneri; A. semicostatus; A. difformis; A. Sauzeanus; Belemnites acutus; B. infundibulum; Cardinia Listeri vars. hybrida and cuneata; Pecten Thiollieri; Monotis inaequivalvis; Spiriferina Walcotti; Acrodus nobilis.

Historical middle-series shell associations
The four separately described associations are: Gryphaea arcuata with Montlivaltia Guettardi; Hippopodium ponderosum with Cardinia concinna and Lucina limbata; Cardinia Listeri with Unicardium cardioides; and oyster-only banks. They are historical observations of different concentrations, not four newly named beds.

Angulata/boundary sequence, horizon 1: Liasicus
Alsatites liasicus was figured from Redcar by Wright. The old Ammonites johnstoni record at Leigh-Dam Scar may be a misidentified Waehneroceras; a Planorbis-age occurrence is not established.

Angulata/boundary sequence, horizon 2: Depressa
Schlotheimia cf. pseudomoreana is common in a narrow band. Specimens resembling S. depressa may occur nearby. Records of true S. angulata, an Extranodosa-subzone species, are ambiguous and require confirmation.

Angulata/boundary sequence, horizon 3: basal Sinemurian
Metophioceras cf. group brevidorsale occurs near the top of the shales at the base of Jenny Leigh’s Scar; its proposed biohorizon is uncertain. The GCR equates this with Gad bed 17 and its restarted “Angulatus bed 1”. Approximately 0.3 m separates the last Hettangian Schlotheimia from the first Sinemurian arietitids in the cited observations.

Lower–middle Bucklandi sequence, horizon 1: Conybeari
Metophioceras spp. occur in the lowest Jenny Leigh’s reef and extend to Gad bed 31, equated by the GCR with Tate and Blake’s bed 90.

Lower–middle Bucklandi sequence, horizon 2: Rotiforme
Common Coroniceras hyatti and some C. cf. rotiforme are reported in phosphatised nodules assigned to Tate and Blake’s bed 75.

Lower–middle Bucklandi sequence, horizon 3: Rotiforme
Coroniceras ex group rotiforme occurs on Jenny Leigh’s Scar. Similar tuberculate Coroniceras were recorded from historical beds 57 and 58.

Lower–middle Bucklandi sequence, horizon 4: ?Bucklandi
Stokesley Scar yields Arnioceras sp. and cf. Arietites sp.; an apparently similar assemblage also includes Charmasseiceras. The GCR’s age assignment remains qualified.

Lower–middle Bucklandi sequence, horizon 5: Lyra
Coroniceras cf. lyra is recorded from upper East Scar. The highest Coroniceras was reported at historical bed 14; large Paracoroniceras about 1.5 m higher, probably at bed 11, may represent the same Lyra fauna. This source interpretation is not an exact modern sample tie.

Basal Semicostatum physical package
A shelly sandstone with ferruginous ooliths caps a coarsening-upward trend in the work summarised by the GCR. Its placement near the base of the Semicostatum Chronozone is a separately sourced observation, without a forced Red-sample equivalence.

Muddy Scipionianum sequence, horizon 1
The lowest of three distinct ammonite faunas in grey shale with calcareous nodules contains Agassiceras sp.

Muddy Scipionianum sequence, horizon 2
The succeeding fauna contains abundant Arnioceras with ?Pararnioceras.

Muddy Scipionianum sequence, horizon 3
The higher fauna again contains Agassiceras, including large crushed specimens. The three levels together are linked by Getty to Agassiceras scipionianum, A. personatum, A. cf. decipiens and Arnioceras acuticarinatum; that collective species list is not divided among individual horizons without evidence.

Succeeding Scipionianum level, source horizon 1 of next package
Large crushed, compressed-whorled ?Agassiceras occurs below the following Sauzeanum faunas. The source restarts its horizon numbering here; this is not a second use of a modern Red code.

Sauzeanum sequence, source horizon 2
Euagassiceras sp. 1, ?Arnioceras sp. and Nannobelus sp.

Sauzeanum sequence, source horizon 3
?Euagassiceras sp., ?Pararnioceras and Arnioceras sp.

Sauzeanum sequence, source horizon 4
Euagassiceras sp. and Arnioceras sp.

Sauzeanum sequence, source horizon 5
Euagassiceras sp. alone is listed. The GCR estimates approximately 15 m for the Scipionianum–Sauzeanum shale and mudstone package. Its separate approximate 38 m Jenny Leigh’s–East Scar estimate is not to be added to the 2020 log. These numbered lists are Page’s separate faunal schemes, with their own scope and uncertainties.

Additional historical faunal records
Spath’s 1925 schlotheimiid determinations included Schlotheimia exeoptycha, S. cf. complanata, S. cf. depressa and reported true S. angulata, but lacked reliable stratigraphic control. The latter identification still requires confirmation. The GCR also reports Microderoceras birchi, indicating the Birchi Subzone, without supplying a modern sample position. Historic collections contain rare Hybodus and Acrodus shark remains and ichthyosaur and plesiosaur material; these do not establish the age or identity of the tooth in the Millclose photograph.

Siliceous Shale Member: High Stone and related reef context

Hard, sandy calcareous shale at High Stone has yielded Oxynoticeras and ?Eoderoceras. The GCR interprets Oxynotum-age strata and possibly part of the early Raricostatum Chronozone, Densinodulum Subzone. Simpsoni and Obtusum faunas include records from loose specimens presumed to have come from submerged beds; their original in-situ position is not established by those finds.

Ironstone Shale Member; possible Pyritous Shale Member: West Scar

West Scar at Coatham exposes shale with iron-rich, possibly sideritic carbonate-nodule bands. The GCR tentatively places these in the upper Sinemurian–lower Pliensbachian, with possible upper Raricostatum, Jamesoni and Davoei ammonite records. The possible presence of the Pyritous Shale Member and some age assignments remain uncertain; neither is asserted beneath Millclose shingle.

Staithes Sandstone Formation: outer Coatham Rocks

Silty shale and sandstone form Inner Height and Outer Height in the outer part of Coatham Rocks. The GCR records Oxytoma, Pseudopecten, Gryphaea, belemnites and ammonites: Aegoceras or Oistoceras in the lowest scar beds supports the Davoei Chronozone, and Amaltheus supports the Margaritatus Chronozone. These Pliensbachian rocks are a separate nearby exposure, not a layer shown beneath the main collecting beach.

Structure and limits of correlation
The reef outcrops lie on the western limb of a gentle anticline. Discontinuous reefs, submerged gaps, shifting sand and changing names complicate correlation. Historical pier-column references located the nineteenth-century beds; they are not present-day navigation directions. Outer reefs remain hazardous, and protected bedrock may require permission and consent before sampling.

References
Atkinson, Wignall & Page (2020), The Hettangian–Sinemurian strata of Redcar: facies and palaeoecology
Tate & Blake (1876), The Yorkshire Lias, pp.47–62 and systematic palaeontology
Page (2004), Redcar Rocks, in British Lower Jurassic Stratigraphy, GCR 30, pp.245–250
Lord (1971), Revision of some Lower Lias Ostracoda from Yorkshire, Palaeontology 14, 642–665
Gründel, Kaim, Nützel & Little (2011), Early Jurassic gastropods from England
BGS Lexicon: Redcar Mudstone Formation