Saltwick Bay Fossil Hunting

1758 – one of the earliest recorded Yorkshire fossil reptiles was found near Whitby and the Saltwick coast
Early records from the Whitby–Saltwick coast include one of the first fossil reptiles noted from the Yorkshire Jurassic. Later reviews make clear that the Saltwick coast formed part of this earliest phase of marine reptile discovery on the Yorkshire coast.

1791 – another early crocodile was recorded from the Whitby–Saltwick coast
Further crocodile material was recorded from the same general stretch of coast before the end of the eighteenth century, showing that the Saltwick area had already become known for reptile remains well before the great nineteenth-century fossil boom.

1819 – the first recorded Yorkshire ichthyosaur came from the Whitby–Saltwick coast
The first recorded ichthyosaur from the Yorkshire coast was collected in 1819 from the Whitby area, and later summaries include Saltwick among the classic localities on that reptile-rich stretch. This marked the beginning of Yorkshire’s long history of important ichthyosaur finds.

1821 – another ichthyosaur was found from the same coast
A second important ichthyosaur discovery followed in 1821, reinforcing the growing reputation of the Whitby–Saltwick coast for marine reptile fossils from the Lias.

1822 – the first Yorkshire plesiosaur remains were reported from the Whitby–Saltwick coast
By 1822, plesiosaur material had also been reported from this stretch of coast. This added another major marine reptile group to the already important fossil record of the area.

1824 – an almost complete fossil crocodile was found at Saltwick Bay
An almost complete crocodile skeleton was discovered at Saltwick Bay in 1824. This became one of the bay’s most notable early vertebrate finds and helped confirm Saltwick as an important marine reptile locality in its own right.

1828 – Young and Bird summarised the rich fossil reptile record of the Whitby and Saltwick coast
In their classic work on the Yorkshire coast, Young and Bird recorded seven crocodiles, forty or more ichthyosaurs and four fragments of plesiosaurs from the Lias of the Whitby district, with Saltwick specifically among the important localities. Their work helped establish the area as one of Britain’s great early Jurassic reptile coasts.

1881 – the Saltwick Formation was named after Saltwick Bay
The Middle Jurassic Saltwick Formation takes its name from Saltwick Bay. This gave the locality a permanent place in British stratigraphy and reflects its importance in the Jurassic geology of Yorkshire.

Late 20th century – Saltwick Bay became recognised as one of the key Whitby sections linking Lower and Middle Jurassic rocks
Modern geological work showed that the coast between Whitby and Saltwick is especially important because it exposes the transition from the Whitby Mudstone Formation into the Middle Jurassic Ravenscar Group, including the Saltwick Formation. This added major stratigraphic importance to a bay already well known for fossils.

2001 – dinosaur footprints from the Saltwick Formation were described from the Yorkshire coast
Modern ichnological work showed that the Saltwick Formation preserves dinosaur footprints, including tracks attributed to stegosaurian dinosaurs and fish-swimming traces. This added important terrestrial trace fossils to a locality better known for ammonites, belemnites, plants and marine reptile remains.

Modern understanding – Saltwick Bay remains one of Yorkshire’s most varied Jurassic fossil localities
Today Saltwick Bay is known for ammonites, belemnites, jet, fossil plants and occasional reptile remains, while the beds named after the bay are also important for dinosaur footprints and Middle Jurassic plant material. Its significance lies in combining classic collecting ground with one of the key Jurassic reference sections east of Whitby.

Saltwick Bay is not a single simple vertical cliff log. The lower part of the story is exposed mainly on the wave-cut foreshore around Saltwick Scar, Saltwick Nab and Black Nab, where the upper Mulgrave Shale Member and almost the whole Alum Shale Member can be examined, while the main cliff and fallen blocks show the Dogger Formation, the type Saltwick Formation and the lowest Eller Beck Formation. Formal Howarth bed numbers are retained for the Whitby Mudstone where published; for the Saltwick and Eller Beck formations, the SB numbers used below are site-use divisions based on real lithological and palaeontological breaks and are not formal published bed numbers.

LIAS GROUP

Whitby Mudstone Formation (Lower Toarcian)

Mulgrave Shale Member

Bed 35 — Whalestones (c. 0.92 m)

This is the lowest part of the Saltwick Bay Whitby Mudstone succession normally seen, exposed only at very low water on the seaward edge of the foreshore. Large ovoid calcareous concretions, some up to about 3 m long, lie in grey bituminous shale and form one of the most conspicuous low-tide markers in the whole locality. Ammonites include Cleviceras exaratum, with less common Harpoceras serpentinum and Lytoceras crenatum; belemnites include Acrocoelites trisulcolosus and A. ilminsterensis. This bed lies within the Harpoceras falciferum Zone, Exaratum Subzone, and represents strongly oxygen-poor offshore mud deposition with early diagenetic concretion growth.

Bed 36–40 — Upper Jet Rock Interval, Including The Curling Stones, Top Jet Dogger And Millstones (about 3.4 m above Bed 35)

These beds continue the classic Jet Rock facies of dark grey to brown-grey bituminous shale with conspicuous concretionary marker bands. Bed 37, the Curling Stones, contains almost spheroidal pyrite-skinned concretions; Bed 39, the Top Jet Dogger, is a persistent argillaceous limestone band and should not be confused with the much younger Middle Jurassic Dogger Formation; Bed 40, the Millstones, carries giant flattened lenticular concretions reaching more than 4.5 m across. Belemnites remain common, especially Acrocoelites trisulcolosus and A. ilminsterensis. This interval belongs to the upper part of the Exaratum Subzone and includes the elegans biohorizon. It is one of the classic Whitby jet-bearing, finely laminated anoxic shale intervals, deposited under strongly restricted bottom-water conditions with little benthic disturbance.

Bed 41–43 — Lower Bituminous Shales / Tubularis Bed Interval (c. 13.8 m)

Grey bituminous shales with a row of scattered pyrite-skinned concretions and abundant Pseudomytiloides near the middle. Ammonites include the Harpoceras falciferum group, including H. mulgravium, with Dactylioceras and Nodicoeloceras incrassatum; belemnites include Parapassaloteuthis robusta, P. polita, Acrocoelites subtricissus, A. inequistriatus, and the distinctive Youngibelus tubularis and Y. simpsoni, the last two especially associated with Bed 43, the old tubularis Bed. The base of Bed 41 at Saltwick effectively marks the base of the Falciferum Subzone in the classic local usage. Fossils are commonly flattened or pyritized, and the interval represents continued bituminous offshore shale sedimentation with only sparse benthic life.

Bed 44–47 — Upper Bituminous Shales (c. 9 m, excluding the Ovatum Bed sensu stricto)

This upper part of the Mulgrave Shale Member consists of grey bituminous shales with scattered concretions, a sideritic mudstone near the base of the 46–47 interval, and a fauna dominated by ammonites and belemnites. The lower part yields the falciferum biohorizon with Harpoceras of the falciferum group, Dactylioceras, Phylloceras heterophyllum and belemnites such as Parapassaloteuthis polita and Acrocoelites subtenuis. Higher beds pass into the ovatum biohorizon, with occasional Ovaticeras ovatum. Compared with the Jet Rock below, lamination is weaker and organic content lower, although conditions were still dysoxic enough to preserve flattened cephalopods, fish debris and locally articulated vertebrate material.

Bed 48 — Ovatum Bed (c. 0.25 m, within a broader c. 1–2 m ovatum interval)

A double row of large sideritic concretions in grey shale, with irregular masses of pyrite and locally spectacular concentrations of belemnites traditionally called “belemnite battlefields”. Ovaticeras ovatum is the key ammonite, with Dactylioceras and Phylloceras subordinate. This is the formal top of the Mulgrave Shale Member at Whitby–Saltwick, and it provides one of the clearest field datums on the foreshore. The bed records a concretion-rich omission-prone horizon at the transition from the more anoxic Mulgrave shales into the less bituminous Alum Shale regime above.

Alum Shale Member

Bed 49–50 — Hard Shale Beds (c. 6.3–6.4 m)

Grey, non-bituminous to only weakly bituminous shales with calcareous concretions, pyritic masses and a thin red sideritic mudstone band near the top. Dactylioceras commune and D. temperatum are characteristic, together with Hildoceras of the lusitanicum group, Parapassaloteuthis polita and Acrocoelites subtenuis. The base of Bed 49 marks the base of the Commune Subzone in Howarth’s classic Whitby succession. The change from the Mulgrave Shale below is both lithological and environmental: the sediment is less bituminous, less finely laminated and more oxygenated, though still a restricted offshore mudstone facies.

Bed 51–59 — Lower Main Alum Shale Beds (c. 12.3 m)

Alternating soft grey shales and bands of calcareous nodules form the lower half of the classic alum-working interval. The fauna of the lower part is dominated by Dactylioceras commune and allied forms; higher beds yield D. athleticum, Hildoceras of the lusitanicum group, Pseudolioceras lythense, Phylloceras heterophyllum and rare Frechiella subcarinata, with abundant belemnites. The bivalve Dacromya ovum may be common at some levels and can occur with attached Discinisca reflexa. Much of the historic marine reptile material attributed to Saltwick came from the alum shales worked in this part of the cliff or from nearby equivalent beds. These shales weather into brittle pale grey flakes and represent restricted offshore mud deposition with only a limited benthic fauna.

Bed 60–64 — Upper Main Alum Shale Beds (c. 3.2 m)

Grey shale with several nodule bands, more strongly fossiliferous than much of the lower Main Alum interval. Ammonites include Peronoceras fibulatum, P. turriculatum, P. perarmatum, P. subarmatum, Zugodactylites braunianus, Pseudolioceras lythense, Hildoceras of the bifrons group, Phylloceras and Lytoceras cornucopia. These beds encompass the turriculatum and braunianus biohorizons within the Fibulatum Subzone. The faunal change shows that the upper Main Alum Shales are not just anonymous clay but a tightly resolved ammonite succession within the lower Hildoceras bifrons Zone.

Bed 65–72 — Cement Shale Beds (about 5.8 m exposed, top truncated)

The Cement Shales form the uppermost exposed Whitby Mudstone at Saltwick Bay. They are grey shales with layers and rows of calcareous concretions once worked for cement manufacture. Ammonites include Hildoceras bifrons and related forms, Porpoceras, Catacoeloceras crassum and Phylloceras heterophyllum, together with abundant belemnites and bivalves such as Nuculana and Gresslya. These beds span the upper Fibulatum and Crassum subzones of the bifrons Zone. At Whitby–Saltwick the overlying Dogger unconformity cuts out the highest part of the member, so the section is slightly top-truncated rather than perfectly complete.

Dogger Formation (Aalenian)

Bed SB0 — Dogger Formation, Erosive Marine Ironstone–Sandstone Bed (c. 0.75–1.5 m)

At Saltwick Bay the Dogger is a thin but critical transgressive unit resting sharply and unconformably on the Alum Shale Member. It is a yellow-brown weathering, bioturbated ferruginous sandstone to ironstone, commonly coarse and locally pebbly, with berthierine ooids, phosphatic pebbles, mudstone clasts and reworked ammonite and bivalve fragments derived from the underlying Toarcian shales. Sand-filled burrows descend from the Dogger into the Alum Shale. In Long Bight and nearby parts of the cliff the bed thins and may be almost cut out by overlying Saltwick channel sandstones, showing that post-Toarcian erosion and early Aalenian incision were both significant. Environmentally the Dogger records a shallow marine transgressive lag and sheet sand deposited after uplift, gentle folding and erosion at the end of the Lower Jurassic.

RAVENSCAR GROUP

Saltwick Formation (Aalenian)

No formal bed-by-bed numbered cliff log is in general published use for the Saltwick Formation at Saltwick Bay, even though the formation itself takes its name from this locality and has its type section here. The SB divisions below are therefore practical site-use horizons based on the real lithological architecture of the cliff: basal plant-bearing sands, channel bodies, freshwater marker beds, named plant horizons and the upper marine flooding surface below the Eller Beck Formation.

Bed SB1 — Basal Saltwick Channel-Fill Sandstones, Siltstones And The Whitby Plant Bed

The lowest Saltwick Formation above the Dogger consists of fine-grained sandstones, siltstones and grey mudstones with abundant plant debris and rootlets. The famous Whitby Plant Bed lies toward the base of the formation and is best developed in the south-Whitby–Long Bight part of the same coastal section. It represents a plant-rich lens within channel-fill sandstone. Large sandstone-filled root systems descend from the Saltwick Formation into the Dogger and locally even into the Alum Shale, demonstrating pedogenesis and plant colonisation on exposed or very shallowly buried surfaces. Fossils from this lower plant-rich interval include abundant bennettitalean, conifer and fern remains such as Williamsonia, Weltrichia, Ptilophyllum, Elatides thomasii and stems of Neocalamites nathorstii. Depositional environment was coastal plain to fluvio-deltaic, with channels, crevasse splays, floodplain muds and marshy vegetated surfaces.

Bed SB2 — Lower Saltwick Incised Channel Complex With Coalified Logs

West of the main Saltwick Bay amphitheatre and in the adjoining cliff section the Dogger is locally almost cut out by a sandstone-filled Saltwick channel whose western margin is clear in section. Large coalified logs occur at or near the base, and siltstones and fine sandstones show local synsedimentary disturbance. These are not simply featureless “deltaic sands” but the preserved fills of substantial fluvial channels, locally with lateral accretion surfaces and point-bar style architecture. The presence of large woody debris indicates vigorous transport from nearby vegetated land, while the associated muddy abandoned-channel deposits record quieter water after channel abandonment.

Bed SB3 — Unio Bed And Lower Dinosaur-Track Horizon (about 6.2 m above the Dogger)

The Unio Bed is a distinctive lower Saltwick marker horizon recognised in fallen blocks by a thin reddish sideritic siltstone skin at its base. It lies about 6.2 m above the Dogger and contains occasional freshwater bivalves traditionally called Unio, now usually referred to Unio kendalli. This horizon, and a sandstone about 6 m higher, have yielded several dinosaur footprint-bearing blocks. Tracks include tridactyl bipedal prints, swimming or raking traces, and sauropod footprints, showing repeated exposure of soft sediment on a low-gradient floodplain, crevasse-splay or very shallow channel-margin surface. The bed is one of the most collector-relevant horizons in the lower Saltwick Formation because it ties a named freshwater shell bed directly to the classic Whitby dinosaur ichnology.

Bed SB4 — Middle Saltwick Floodplain, Crevasse-Splay And Abandoned-Channel Interval

Above the lower marker horizons, much of the formation consists of alternating grey mudstone, yellow-grey siltstone and yellow to pale brown sandstone in repeated floodplain and fluvial cycles. Plant fragments and rootlets are common, and regionally thin coals, seatearth-like mudstones and sideritic ironstone nodules may occur. At Saltwick Bay this part of the cliff includes mudstone-prone intervals between more resistant sand bodies, and it represents the broadest environmental spectrum of the type section: active river channels, levees, crevasse splays, ponded or abandoned channels, marshes and vegetated floodplain soils. These beds are the reason the formation works so well as an analogue for fluvio-deltaic reservoir architecture, because the channel bodies are nested within finer overbank facies rather than forming one single homogeneous sandstone sheet.

Bed SB5 — Higher Named Plant Horizons, Including The Zamites Bed, Equisetum And Coniopteris Beds, Matonidium Bed And Waterfall Bed

Higher in the Saltwick Formation a series of named plant beds has long been recognised in the cliffs between Jump Down Bight and Saltwick. The Zamites Bed is especially rich in bennettitalean remains and is important because the fronds Zamites gigas, the female flower Williamsonia gigas and the male flower Weltrichia sol occur in close association, providing classic evidence that these organs belonged to the same parent plant. Other named Saltwick horizons include the Equisetum and Coniopteris Beds, the Matonidium Bed and the Waterfall Bed, with an E. laterale bed above the last. The Matonidium Bed is notable for well-preserved fronds of Matonidium goeppertii. These horizons show that the upper Saltwick succession was repeatedly capable of preserving delicate floodplain vegetation in quiet-water settings between episodes of channel migration and sand influx.

Bed SB6 — Upper Saltwick Channelised Sandstones Beneath The Eller Beck Marine Flooding Surface

The upper part of the formation, seen in the higher cliff and from the cliff-top path above the old alum workings, shows renewed channelling and multistorey sandstone development. The sandstones are commonly cross-stratified, locally sharp-based and laterally impersistent, with interbedded grey mudstones representing abandoned channels or floodbasin deposits. This upper channelised interval records the last major non-marine phase at Saltwick Bay before marine conditions returned. It should not be forced into a false laterally continuous “bed stack”: channel incision, lateral amalgamation and erosional cut-out are fundamental features of the type section.

Total Thickness Of The Saltwick Formation In The Saltwick Bay Type Cliff: About 30 Metres Exposed Here, Within A Regional Formation Thickness Of Up To About 50 Metres East Of Whitby

Eller Beck Formation (Late Aalenian To Earliest Bajocian)

Bed SB7 — Basal Eller Beck Ironstone And Mudstone Unit (generally less than 3 m)

The base of the Eller Beck Formation is an abrupt marine flooding surface above the plant-rich Saltwick Formation. At Saltwick Bay the lower unit comprises fossiliferous ooidal ironstone or ferruginous sandstone at the base, passing up into grey calcareous mudstone with subordinate sideritic ironstone. Marine bivalves are common, and the change from rooted non-marine Saltwick facies below is immediate and striking. This bed records the return of shallow marine conditions across the Saltwick floodplain surface.

Bed SB8 — Upper Eller Beck Ripple-Laminated Marine Sandstones (c. 4–6 m; about 6 m in the Whitby–Saltwick cliff)

The upper Eller Beck is a prominent orange-weathering unit at the top of the Saltwick Bay cliff, consisting predominantly of fine- to medium-grained ripple-laminated sandstone with burrows such as Diplocraterion and, regionally, Rhizocorallium. Shelly fossils are less concentrated than in the basal ironstone–mudstone unit, but marine bivalves and bioturbation remain characteristic. The formation is the first truly marine unit above the type Saltwick Formation and signals the end of the classic Whitby plant-and-footprint facies. Its depositional environment was shallow marine, sand-dominated and more oxygenated than the estuarine to floodplain Saltwick beds below.

Structural Style And Exposure

Saltwick Bay combines cliff and foreshore exposures in a broad asymmetric synclinal setting rather than one cleanly measured face. The synclinal axis lies around Long Bight, the dip swings across the section, and the lower Whitby Mudstone beds are exposed progressively on the foreshore while the Middle Jurassic formations dominate the cliff. Old alum quarrying at Saltwick Nab and in the bay has greatly modified the natural topography, enhancing access to some horizons while destroying others. Within the Saltwick Formation, erosive channels, log lags, local soft-sediment deformation and root penetration into older units are primary depositional features and should not be mistaken for later tectonic repetition.

Depositional Environment

The Saltwick Bay succession records a major Jurassic environmental shift. The Mulgrave Shale Member and lower Alum Shale Member represent offshore mud deposition in oxygen-poor to dysoxic marine waters, with the most anoxic interval in the bituminous Jet Rock and Bituminous Shales where jet, pyrite and flattened cephalopods are common. The higher Alum Shale reflects somewhat less bituminous but still restricted marine shelf conditions. The Dogger Formation is a thin marine transgressive lag and sand sheet laid down on an erosional surface. Above it, the Saltwick Formation records a low-gradient coastal plain and fluvio-deltaic landscape of river channels, crevasse splays, floodplains, ponds, marshes, soils and freshwater shell beds supporting rich vegetation and dinosaur activity. The Eller Beck Formation marks renewed shallow marine inundation across that landscape.

Collector And Scientific Significance

For fossils, Saltwick Bay is important because different parts of the section yield very different assemblages. The Whitby Mudstone provides ammonites, belemnites, bivalves, jet and, historically, marine reptiles from the Mulgrave and Alum shale intervals. The Dogger yields marine reworked fossils and shows the key unconformity. The Saltwick Formation is one of the classic British Middle Jurassic plant localities, with over 90 species known from the Whitby–Saltwick cliff section and type material for many taxa, as well as dinosaur footprints and rare dinosaur bone. The Eller Beck then returns the collector to marine bivalves, burrows and ooidal ironstone. Few Yorkshire coastal sites show such a sharp shift from anoxic sea floor to vegetated floodplain and back to shallow marine conditions in so short a vertical distance.

Total Thickness Covered Here

The composite Saltwick Bay section described here includes about 55 m of middle Whitby Mudstone Formation exposed in cliff and foreshore, a Dogger Formation generally 0.75–1.5 m thick, about 30 m of Saltwick Formation in the type cliff, and about 6 m of lower Eller Beck Formation. In practical field terms, this is a roughly 90 m composite Lower to Middle Jurassic section, though it should always be read as a combined foreshore-and-cliff exposure rather than as one perfectly continuous measured log.

References

Howarth, M.K. (1962a) on the Whitby Mudstone succession and numbered beds at Whitby–Saltwick; and Howarth, M.K. (1962b, 1992) on the ammonites and biohorizons of the Yorkshire Toarcian.
Powell, J.H. (1984). Lithostratigraphic nomenclature of the Lias Group in the Yorkshire Basin.
Simms, M.J., Chidlaw, N., Morton, N. & Page, K.N. (2004). British Lower Jurassic Stratigraphy, Geological Conservation Review Series, including the Whitby to Saltwick account.
Cleal, C.J., Thomas, B.A., Batten, D.J. & Collinson, M.E. (2001). Mesozoic and Tertiary Palaeobotany of Great Britain, Geological Conservation Review Series, including the Whitby–Saltwick palaeobotany account.
Hemingway, J.E. & Knox, R.W.O’B. (1973). Lithostratigraphical nomenclature of the Middle Jurassic strata of the Yorkshire Basin of north-east England.
Knox, R.W.O’B. (1973). The Eller Beck Formation (Bajocian) of the Ravenscar Group of north-east Yorkshire.
Scrutton, C. & Powell, J. (eds) (2006). Yorkshire Rocks and Landscape: A Field Guide, excursion on Whitby to Saltwick.
British Geological Survey Lexicon entries for Whitby Mudstone Formation, Mulgrave Shale Member, Jet Rock, Alum Shale Member, Dogger Formation, Saltwick Formation and Eller Beck Formation.
Whyte, M.A. & Romano, M. (1993, 2001) and Romano, M., Whyte, M.A. & Manning, P.L. (1999) on dinosaur footprints from the Saltwick Formation.
Manning, P.L., Egerton, V.M. & Romano, M. (2015). A new sauropod dinosaur from the Middle Jurassic of the United Kingdom.