Hayburn Wyke Fossil Hunting

1829 – John Phillips provided one of the earliest records of fossil plants from Hayburn Wyke
One of the earliest known scientific records of Hayburn Wyke plant fossils was published by John Phillips in 1829. This marks the beginning of the site’s documented history as an important Yorkshire Jurassic plant locality.

1837 – Lindley and Hutton recorded and described plant fossils from Hayburn Wyke
Lindley and Hutton included Hayburn Wyke material in their classic fossil plant work, making this one of the earliest major milestones in the scientific study of the site. Their work helped establish the importance of the locality for well-preserved Jurassic plant remains.

1864 – Leckenby collected important plant material from Hayburn Wyke
Leckenby collected from Hayburn Wyke in the mid nineteenth century, and his specimens later became part of the site’s important historic record. These collections helped build knowledge of the flora and are still significant in the history of research on the locality.

1875 – Phillips referred to Leckenby’s Hayburn Wyke specimens
Phillips later mentioned Leckenby’s Hayburn Wyke collections, helping preserve their place in the developing scientific understanding of the site’s Jurassic flora.

1900 – Seward summarised the nineteenth-century records from Hayburn Wyke
By 1900, the earlier discoveries from Hayburn Wyke had become important enough to be brought together in Seward’s summary of the Yorkshire Jurassic flora. This marked a key step in recognising the site as a major plant fossil locality rather than just a source of scattered finds.

Early 20th century – Hamshaw Thomas collected extensively from Hayburn Wyke
Hamshaw Thomas collected large amounts of plant material from the section in the early twentieth century. Although much of this work was not fully published at the time, it formed an important part of the site’s research history and helped expand the known flora.

1944–1955 – Harris and Bose described important Hayburn Wyke plant species
Through a long series of publications between the 1940s and 1950s, Harris and Bose described various bennettite, ginkgophyte, czekanowskialean and conifer foliage from Hayburn Wyke. This was one of the most important phases in the scientific study of the locality.

1961–1979 – Harris’s monographs revealed the full importance of the Hayburn Wyke flora
The full diversity of the Hayburn Wyke flora only became clear through Harris’s major monographic work on the Yorkshire Jurassic floras, published between 1961 and 1979. This established Hayburn Wyke as one of the key Jurassic plant sites in Britain.

Late 20th century – several species were recognised as first described from Hayburn Wyke
Later synthesis work showed that a number of important plant taxa were first described from Hayburn Wyke, including Cladophlebis haiburnensis, Bucklandia gigas, Otozamites leckenbyi, Otozamites mimetes, Otozamites parallelus, Otozamites tenuatus, Weltrichia sol and Baiera furcata. The liverwort Hepaticites haiburnensis is especially significant because it is known only from this locality.

1999 – van Konijnenburg-van Cittert and Morgans documented the field geology of the plant beds
Modern field work provided a clearer geological framework for the Hayburn Wyke plant beds and helped place the main fossil horizons more accurately within the Saltwick Formation. This was one of the most important modern milestones for understanding exactly where the flora occurs.

Modern understanding – Hayburn Wyke remains one of Yorkshire’s most important Jurassic plant fossil localities
Today Hayburn Wyke is recognised as a key Aalenian plant site with a rich and well-preserved flora of about 60 species, especially cycads, bennettites, ferns, ginkgophytes and conifers. Its importance lies not only in the number of species present, but also in the fact that several were first described from here and one, Hepaticites haiburnensis, is unique to the site.

At Hayburn Wyke the bedrock section is not a single clean cliff log. Thick glacial boulder clay caps the Middle Jurassic cliffs, the exposure is scattered across the rocky foreshore and the beck-cut waterfall gully, and parts of the section are often obscured by landslip. The main plant-bearing beds lie in fine-grained Saltwick Formation sediments in the centre of the bay, while the overlying Eller Beck Formation comes down to shore level at Iron Scar to the south.

Older site citations sometimes referred the Hayburn Wyke Plant Bed broadly to the Cloughton Formation, but modern GCR and BGS lithostratigraphy place the main Hayburn Wyke plant beds in the Saltwick Formation. A few higher Harris plant horizons above Iron Scar belong instead to the basal Sycarham Member of the Cloughton Formation and are included below only as context.

RAVENSCAR GROUP

Saltwick Formation (Aalenian)

Section Character Of The Saltwick Formation At Hayburn Wyke

Only the upper part of the Saltwick Formation is exposed at Hayburn Wyke. The formation here consists of grey mudstones, yellow-grey siltstones and yellow sandstones deposited in fluvial, fluviodeltaic and paralic settings. Published logs show repeated changes from vegetated swamp and floodplain mudstone into washover-fan, lagoonal and barrier-bar style sands and silts. The finer-grained beds yield the best-preserved and most diverse plant fossils, whereas the sandier units commonly contain only fragmentary, often charcoalified plant debris and wood.

Bed HW1 — Hayburn Beck Beds 1–2 (lower exposed Hayburn Wyke Saltwick interval)

These lower named Hayburn Wyke horizons represent the fine-grained floodplain and swamp facies exposed in the centre and north side of the bay. They are composed mainly of grey mudstone and yellow-grey siltstone with thin fine sandstone interbeds, local rootlets, nodular siderite and plant debris. The general setting was a low-lying coastal alluvial plain with shallow standing water, weak drainage and repeated influxes of fine clastic sediment. Plant remains are common, but the best preserved specimens occur in the quieter mudstone-siltstone parts of the interval rather than in the sandier beds.

Bed HW2 — Hayburn Beck Zamites Bed / Hayburn Wyke Zamites Bed (main Hayburn Wyke Plant Bed)

This is the principal fossil-plant horizon of the locality and the bed most collectors and palaeobotanists mean when referring to the Hayburn Wyke Plant Bed. It is intensely localized both vertically and laterally and lies within fine-grained argillaceous floodplain or swamp deposits, probably with nodular siderite and abundant fossil wood. Ferns are particularly common, including Clathropteris obovata, Coniopteris bella, C. hymenophylloides, C. murrayana, C. simplex, Matonidium goeppertii and Phlebopteris woodwardii; the pteridosperm Pachypteris lanceolata is also frequent. In some patches the bed is dominated by great numbers of Zamites gigas leaves with only a few Williamsonia stems, Williamsonia gigas flowers and Weltrichia sol, suggesting concentration of organs from a very local bennettitalean vegetation. This is the key vegetated-swamp horizon at Hayburn Wyke and the source of much of the classic museum material.

Bed HW3 — Hayburn Tindall Point Plant Bed

The Tindall Point Plant Bed represents another fine-grained Saltwick plant horizon higher in the exposed upper formation. Published section logs place it within beds deposited in lagoon-margin to washover-fan settings, where thin sheet sands repeatedly spread across muddy vegetated ground. As at the main Zamites Bed, the finer sediments preserve the more diverse flora, whereas adjoining sandy beds tend to yield only comminuted or charcoalified fragments. This horizon is important because it shows that the Hayburn flora was not restricted to one single paper-thin layer but recurred through a short interval of swampy to lagoonal sedimentation.

Bed HW4 — Phlebopteris Bed Below Iron Scar And Upper Transitional Saltwick Beds

The uppermost exposed Saltwick just below Iron Scar includes the Phlebopteris Bed together with the final paralic beds immediately beneath the marine Eller Beck transgression. At Iron Scar the top of the Saltwick is pale-grey delicately laminated siltstone-shale with comminuted plant material, very small Rhizocorallium-like burrows, occasional runnels and rare bivalves on the bases of some runnel casts, together with poorly laminated mudstone containing some sphaerosiderite. These beds show that the upper Saltwick was already becoming more waterlogged and marginal-marine in character before the arrival of the Eller Beck sea. Plant fossils still occur, but the facies indicate quieter shallow-water conditions than the main swamp plant bed below and the beginning of a transition into brackish or marine-influenced sedimentation.

Eller Beck Formation (Late Aalenian To Earliest Bajocian)

Section Character Of The Eller Beck Formation At Hayburn Wyke And Iron Scar

The overlying Eller Beck Formation is the thin marine incursion that flooded the Saltwick delta plain. At Hayburn Wyke the succession dips gently southward so that the unit reaches beach level at Iron Scar, the type locality of the formation. The Eller Beck here is a classic transgressive–regressive shallow-marine succession, beginning with a thin basal ironstone and passing upward through shelly silty shale into ripple-laminated and flat-bedded sandstone deposited by wave and tidal currents along a prograding strandline. The detailed subdivision below follows Knox’s published Iron Scar section.

Bed HW5 — Basal Eller Beck Transgressive Ironstone (up to 0.08 m)

The base of the formation is a very thin but highly distinctive ooidal sideritic ironstone or ironstone-rich mudstone resting sharply on the plant-bearing Saltwick beds below. Scattered marine fossils occur within it, and ironstone-filled burrows including Diplocraterion and Rhizocorallium penetrate the base. This is the flooding surface at Hayburn Wyke: a condensed marine transgressive bed marking abrupt replacement of the vegetated delta plain by shallow marine conditions.

Bed HW6 — Eller Beck Shale Unit (1.22 m)

Above the basal ironstone lies silty shale with shell casts in the lower part and thin laminae of fine sand higher up. This is the lowest substantial marine mudstone interval at Iron Scar. Its fauna is less spectacular than that of some higher Yorkshire marine beds, but shell casts and common bioturbation show definite marine colonization. Sedimentation took place in shallow but protected water on the newly flooded platform, before later sandier strandline facies prograded across the site.

Bed HW7 — Eller Beck Lower Sandstone Unit, Laminated Lower Division (0.56 m)

This division is a thin-bedded laminated sandstone with interbedded silty shale and ironstone. It marks the first major increase in sand supply after the initial mudstone phase. Ripple and lamination structures show transport by oscillatory and current action in shallow water, and the mixed sandstone–shale character indicates repeated pulses of reworking rather than uninterrupted sheet-sand deposition.

Bed HW8 — Eller Beck Lower Sandstone Unit, Thin-Bedded Shelly Division (1.83 m)

Thin-bedded sandstone with silty shale intercalations, impersistent beds of silty siderite mudstone and occasional shelly bands forms the main part of the lower sandstone unit. This interval was deposited on a shallow marine platform influenced by wave and tidal currents. Bioturbation is common and indicates that bottom waters were not persistently hostile; published interpretations suggest water depths of only a few metres. The interbedded shelly and sideritic layers record minor fluctuations in energy, salinity and sediment supply across the marine shoreline system.

Bed HW9 — Eller Beck Upper Sandstone Unit (1.68 m)

The top of the Eller Beck Formation at Iron Scar is a flat-bedded sandstone with some symmetrical ripple-marked surfaces and a top penetrated by rootlets. This is the clearest indication that the marine incursion was followed by renewed non-marine sedimentation. The sandstone has been interpreted as part of a shallow strandline or barrier-bar complex laid down under wave and tidal influence and then colonized subaerially or in very shallow brackish settings as the sea retreated or the shoreline prograded. It forms the uppermost marine to marginal-marine sandstone below the return to coal-measures facies of the Cloughton Formation.

Total Thickness Of The Eller Beck Formation At Iron Scar: About 5.4 Metres

Cloughton Formation (Context Above The Main Hayburn Wyke Section)

Sycarham Member

Bed HW10 — Basal Sycarham Member Above Iron Scar (context horizon only)

Immediately above the Eller Beck at and south of Iron Scar, the succession returns to cross-bedded, plant-debris-rich sandstone, siltstone and mudstone with rootlets belonging to the Sycarham Member. Harris recorded higher plant horizons here and nearby, including beds about 5 ft and 25 ft above Iron Scar, the Hayburn Gorse Bed, Thomas Bed 2, and an Equisetum-rich level just above Iron Scar. The latter is notable for being rich mainly in Coniopteris simplex, interpreted as a very local plant community around a small lagoon. These beds are not part of the core Hayburn Wyke Plant Bed section in the centre of the bay and are not always continuously exposed, but they are important context because they explain how the locality passes upward from the marine Eller Beck back into non-marine coal-measures facies.

Palaeobotany

The Hayburn Wyke flora includes about 60 recorded plant species. Particularly important are the liverwort Hepaticites haiburnensis, known only from this locality, and Cladophlebis haiburnensis, first described from here. The flora also includes numerous bennettitaleans such as Bucklandia gigas, Otozamites leckenbyi, O. mimetes, O. parallelus, O. tenuatus and Weltrichia sol, as well as the ginkgoalean Baiera furcata. Charcoalified conifer woods from floodplain mudstones and crevasse-splay sandstones have been described as Cedroxylon, Cupressinoxylon, Taxodioxylon and Xenoxylon phyllocladoides. The Saltwick Formation at Hayburn Wyke has also yielded pterosaur footprints assigned to Pteraichnus, showing that the locality preserves vertebrate trace fossils as well as the better-known plants.

Ammonite Age And Correlation

The Hayburn Wyke plant beds are Aalenian in age. In the current BGS Middle Jurassic framework, the Saltwick Formation is Aalenian and spans from the Murchisonae Zone to about the Bradfordensis interval, while the overlying Eller Beck Formation ranges from about the Bradfordensis interval into the earliest Bajocian Discites interval. The marine flooding at Iron Scar therefore represents a late Aalenian to earliest Bajocian transgression across the top of the Saltwick delta plain.

Depositional Environment

Hayburn Wyke records a clear environmental shift within the lower Ravenscar Group. The Saltwick Formation represents a coastal alluvial and delta-plain setting with vegetated swamps, floodplain muds, abandoned channels, shallow lagoons, washover fans and occasional barrier-like sand bodies; plant colonization, rootlet penetration, fossil wood and nodular siderite are typical. The overlying Eller Beck Formation records the arrival of shallow marine conditions, beginning with a thin transgressive ironstone and passing upward through muddy, shelly, bioturbated beds into sandier wave- and tide-worked shoreline deposits. Above that, the basal Sycarham Member shows rapid return to non-marine coal-measures facies.

Total Thickness Covered Here

At Hayburn Wyke only the uppermost part of the c. 50 m-thick Saltwick Formation is exposed in the main bay, together with about 5.4 m of overlying Eller Beck Formation at Iron Scar and a small amount of basal Sycarham Member for context. The locality should therefore be treated as a composite upper Saltwick–lower Eller Beck–basal Sycarham section rather than as a single uninterrupted cliff log.

References

van Konijnenburg-van Cittert, J.H.A. & Morgans, H.S. (1999). The Jurassic Flora of Yorkshire.
Cleal, C.J., Thomas, B.A., Batten, D.J. & Collinson, M.E. (2001). Mesozoic and Tertiary Palaeobotany of Great Britain, Geological Conservation Review Series No. 22, especially the Hayburn Wyke site account.
Knox, R.W.O’B. (1973). “The Eller Beck Formation (Bajocian) of the Ravenscar Group of NE Yorkshire.” Geological Magazine, 110, 511–533.
Barron, A.J.M., Lott, G.K. & Riding, J.B. (2012). Stratigraphical framework for the Middle Jurassic strata of Great Britain and the adjoining continental shelf. British Geological Survey Research Report RR/11/06.
British Geological Survey Lexicon of Named Rock Units: Saltwick Formation, Eller Beck Formation and Cloughton Formation.
Cox, B.M. & Sumbler, M.G. (2002). British Middle Jurassic Stratigraphy, Geological Conservation Review Series No. 26, especially the Iron Scar–Hundale and Hundale Point–Scalby Ness account.
Whyte, M.A. & Romano, M. (2014). “First record of the pterosaur footprint Pteraichnus from the Saltwick Formation (Aalenian) of the Cleveland Basin, Yorkshire, UK.” Proceedings of the Yorkshire Geological Society, 60, 19–27.