Whitby Fossil Hunting

1758 – one of the earliest recorded Whitby marine reptile finds was described from the alum rock
In 1758, a fossil skeleton from the Whitby alum shales was described by local writers. Later reviews show that this specimen was clearly an early crocodile, making it one of the earliest recorded Jurassic vertebrate discoveries from the Whitby coast.

1819 – the first recorded ichthyosaur from the Yorkshire coast was collected near Whitby
The Whitby–Saltwick coast produced the first recorded ichthyosaur from the Yorkshire coast in 1819. This marked the beginning of Whitby’s long reputation for important marine reptile discoveries from the Lower Jurassic rocks.

1821 – another Whitby ichthyosaur was found and described by George Young
A second ichthyosaur from the Whitby area was found in 1821 and described by the Reverend George Young. This helped establish Whitby as one of the classic British localities for early marine reptile discoveries.

1822 – plesiosaur remains had already been found from the Whitby coast
By 1822, Young and Bird had recorded plesiosaur remains from the Whitby area. This showed that the coast was yielding more than just ammonites and ichthyosaurs, and added another major reptile group to Whitby’s growing Jurassic importance.

1823 – the Whitby Literary and Philosophical Society was founded to keep important local fossils in Whitby
Concern that major Whitby fossils were being lost to collections elsewhere helped drive the creation of the Whitby Literary and Philosophical Society in 1823. Its museum went on to become one of the main homes for the area’s Jurassic discoveries.

1824 – Brown Marshall found the famous fossil crocodile later known as Teleosaurus chapmani
In 1824, Whitby carpenter Brown Marshall spotted the snout of a fossil crocodile sticking out of the cliff and excavated most of the skeleton by working on ropes. The specimen was bought for the museum and became one of Whitby’s great early fossil showpieces.

1824–1828 – George Young and Young & Bird published the classic early Whitby fossil accounts
George Young’s 1824 work and the later publications by Young and Bird helped make Whitby one of the best-known Jurassic fossil localities in Britain. These studies documented the coast’s reptiles, ammonites and other fossils, and were among the earliest illustrated geological accounts of the area.

Before 1842 – the first Whitby plesiosaur skeleton had been collected
The first plesiosaur skeleton from the Whitby coast had been collected by 1842, although it was described somewhat later. This added to Whitby’s already important early record of Jurassic marine reptiles.

1868 and 1884 – Martin Simpson published major ammonite work based on Whitby fossils
Martin Simpson’s studies of Yorkshire ammonites helped cement Whitby’s reputation as one of the classic British ammonite localities. His work built on the earlier foundations laid by Young, Bird and Phillips and became central to the fossil literature of the Yorkshire Jurassic.

20th century – Whitby’s Jurassic succession continued to be a key research section for the Whitby Mudstone Formation
The Whitby–Saltwick coast featured repeatedly in major geological descriptions through the twentieth century, including work by Phillips, Tate and Blake, Fox-Strangways, Herries and Howarth. This confirmed Whitby as a reference area for the Toarcian Whitby Mudstone Formation and its rich ammonite faunas.

Modern understanding – Whitby remains one of Britain’s classic Jurassic fossil localities
Today Whitby is still best known for ammonites from the Whitby Mudstone Formation, together with belemnites, bivalves, fossil wood, jet and marine reptile remains. The Whitby Museum collections, built from discoveries made from the early nineteenth century to the present day, remain an important scientific resource.

Section Architecture

Whitby is not a single simple cliff log. The classic section runs from Whitby East Pier through The Scar, Long Bight and Saltwick Nab into Saltwick Bay, with the lower Toarcian beds folded into a broad asymmetric syncline; the lowest strata actually seen in the main Whitby–Saltwick foreshore are around Howarth Bed 35 in the middle of the Jet Rock, whereas the lower Grey Shale Member and older underlying beds are not normally exposed in this particular coastal tract. Up-section, the Alum Shale Member is truncated by the Dogger unconformity, so the higher Peak Mudstone and Fox Cliff Siltstone members of the Whitby Mudstone Formation are absent at Whitby and cannot be forced into a false continuous cliff log.

LIAS GROUP

Whitby Mudstone Formation (Lower Jurassic: Toarcian)

Mulgrave Shale Member

Bed W1 — Howarth Bed 35, Whalestones (0.92 m)

The Whalestones are a conspicuous low-tide marker bed of large ovoid calcareous concretions, some up to about 3 m long and 1 m thick, set in grey bituminous shale. They form one of the most recognisable features on the outer foreshore between Black Nab and Whitestone Point and mark the lowest level normally seen in the Whitby–Saltwick type section. Ammonites: Cleviceras exaratum is characteristic, with less frequent Harpoceras serpentinum and Lytoceras crenatum. Belemnites: Acrocoelites trisulculosus and A. ilminsterensis. Interpretation: laminated, strongly oxygen-restricted offshore mud in which early diagenetic carbonate nucleated into giant concretions during the lower part of the Toarcian oceanic anoxic interval.

Bed W2 — Howarth Beds 36–38, Middle Jet Rock (c. 2.88 m)

This interval consists of grey bituminous shale with two prominent concretionary horizons: the almost spherical “Curling Stones” of Bed 37 and the more weakly concretionary shales above and below. Bedding is finely laminated, burrowing is effectively absent, and the rock is markedly richer in organic matter than the Alum Shale above. Poor-grade jet and compressed fossil wood may occur, though the best jet-bearing levels are patchy in the Whitby area and more famously worked farther along the coast. Ammonites: still within the exaratum–elegans part of the Serpentinum Zone, with Cleviceras and Harpoceras associations. Depositional Environment: quiet offshore marine mud deposited beneath severely oxygen-depleted bottom waters, with almost no benthic disruption.

Bed W3 — Howarth Bed 39, Top Jet Dogger (0.23 m)

This thin continuous argillaceous limestone forms a persistent band near the top of the Jet Rock. Despite its old field name, it is not the overlying Aalenian Dogger Formation but a limestone within the lower Toarcian bituminous shale succession. It is useful as a field marker because it separates lower laminated jet-bearing shales from the giant-concretion horizon above. Typical Fossils: belemnites, especially Acrocoelites trisulculosus. Interpretation: a brief more calcareous episode during otherwise bituminous mud deposition.

Bed W4 — Howarth Bed 40, Millstones (0.30 m)

The Millstones are giant flattened lenticular concretions, commonly more than 4.5 m across and about 0.3 m thick, resting in or on a thin laminated limestone and standing proud on the outer foreshore. They preserve the sedimentary lamination within them and are one of the classic Whitby collector landmarks. Ammonite Horizon: elegans part of the exaratum interval. Interpretation: exceptionally strong early carbonate cementation within laminated organic-rich mud, developed during the peak restricted facies of the Jet Rock.

Bed W5 — Howarth Beds 41–43, Lower Bituminous Shales / Tubularis Interval (13.8 m)

This thick lower Bituminous Shales package comprises grey to dark grey bituminous shale with a row of scattered pyrite-skinned concretions and a conspicuous shell-rich level containing abundant Pseudomytiloides near the middle. Lamination is still clear but generally less perfect than in the Jet Rock below, and the rock contains less bitumen overall. Ammonites: Harpoceras of the falciferum group, including H. mulgravium, with Dactylioceras and Nodicoeloceras incrassatum. Belemnites: Youngibelus tubularis, Y. simpsoni, Parapassaloteuthis and Acrocoelites. The base of Howarth Bed 41 is effectively a parastratotype for the base of the Falciferum Subzone. Depositional Environment: offshore, still markedly dysoxic to anoxic, but with slightly more episodic faunal colonisation of the water column and more abundant pyritization than in the lower Jet Rock.

Bed W6 — Howarth Beds 44–45, Middle Bituminous Shales (3.5 m)

Grey bituminous shale with a basal row of scattered concretions. This is one of the most ammonite-rich parts of the Mulgrave Shale Member in the Whitby–Saltwick section. Ammonites: Harpoceras of the falciferum group, with Dactylioceras and occasional Phylloceras heterophyllum. Interpretation: continued restricted offshore mud deposition within the classical Harpoceras falciferum fauna, still strongly affected by low-oxygen bottom conditions.

Bed W7 — Howarth Beds 46–47 (lower part), Upper Bituminous Shales (4.98 m)

Grey bituminous shale with a 0.13 m sideritic mudstone at the base. The facies remains dark and organic-rich but is less massively concretionary than lower in the member. Fossils: Dactylioceras, Parapassaloteuthis polita, Acrocoelites subtenuis, A. vulgaris and Simpsonibelus dorsalis. Interpretation: upper part of the restricted Mulgrave sea-floor mudstone regime, still largely inhospitable to benthos and prone to pyrite formation.

Bed W8 — Howarth Bed 47 (upper part) And Bed 48, Ovatum Interval And Ovatum Bed (c. 1.0 m Total Including 0.25 m Ovatum Bed)

This is the classic marker at the top of the Mulgrave Shale Member. Grey bituminous shale with occasional Ovaticeras ovatum passes up into the Ovatum Bed itself, a double row of large sideritic concretions and pyritic masses that can be traced at the base of the cliff between Jump Down Bight and Saltwick Nab. “Belemnite battlefields” may occur at this level, with dense concentrations of belemnites on bedding planes. Ammonites: Ovaticeras ovatum with rare Dactylioceras and Phylloceras. Stratigraphic Significance: this is the formal lithological boundary between the Mulgrave Shale and Alum Shale members at Whitby. Interpretation: a condensed and concretion-rich uppermost restricted-marine horizon formed during slight facies change and episodic reworking at the close of Mulgrave deposition.

Alum Shale Member

Bed W9 — Howarth Beds 49–50, Hard Shales (6.4 m)

The Hard Shales are grey non-bituminous shales with scattered concretions, pyritic masses and a 0.13 m red sideritic mudstone cap. They mark a decisive lithological change above the darker Mulgrave Shales below: lamination is less perfect, benthic disturbance is less completely suppressed, and the rock is more calcareous in places. Ammonites: Dactylioceras commune and D. temperatum, with Hildoceras of the lusitanicum group. The base of Bed 49 marks the base of the Commune Subzone in Howarth’s scheme. Depositional Environment: still offshore marine mud deposition, but under less severely oxygen-poor conditions than the Jet Rock and Bituminous Shales.

Bed W10 — Howarth Beds 51–54, Lower Main Alum Shales (9.5 m)

This thick interval of grey shale with bands of calcareous nodules forms a major part of the classical Whitby East Cliff foreshore and lower cliff section. The shales weather to brittle flakes and were historically worked on a large scale for alum manufacture, especially at Saltwick Nab and Black Nab. Ammonites: abundant Dactylioceras commune and related forms, with Hildoceras of the lusitanicum group and rarer Frechiella subcarinata. Other Fossils: large driftwood logs, belemnites, Gresslya and locally abundant Dacromya ovum. Many of the early Whitby marine reptile finds, including crocodiles and ichthyosaurs from The Scar and the old alum workings, probably came from this broader Main Alum Shale interval. Interpretation: offshore mud accumulation with more active bottom life than in the Mulgrave Shales, but still relatively quiet and fine-grained.

Bed W11 — Howarth Beds 55–59, Upper Commune-Subzone Main Alum Shales (2.8 m)

Grey shale with calcareous nodule bands continuing the Main Alum facies but with a more distinctive athleticum-fauna. Ammonites: Dactylioceras athleticum, other Dactylioceras, Hildoceras of the lusitanicum group, Pseudolioceras lythense, Phylloceras heterophyllum and Lytoceras cornucopia. Interpretation: continued open offshore mud deposition with recurring concretion growth and rich nektonic faunas.

Bed W12 — Howarth Beds 60–63 (part), Lower Fibulatum-Subzone Main Alum Shales (1.33 m)

Grey shale with calcareous nodule bands, faunally distinct from the commune beds below. The base of Bed 60 at Whitby corresponds to the base of the Fibulatum Subzone. Ammonites: Peronoceras fibulatum, P. turriculatum, P. perarmatum, P. subarmatum, Pseudolioceras lythense and Hildoceras of the bifrons plexus. Interpretation: continued marine mud sedimentation, but with a more advanced lower Bifrons-zone fauna and well-developed biostratigraphic precision.

Bed W13 — Howarth Beds 63 (part)–64, Upper Main Alum Shales / Braunianus Horizon (1.9 m)

Shale with bands of calcareous nodules marking the top of the Main Alum Shales proper. Ammonites: Peronoceras fibulatum, P. turriculatum, Zugodactylites braunianus, Pseudolioceras lythense, Hildoceras of the bifrons group, Phylloceras heterophyllum and Lytoceras cornucopia. This interval corresponds to the braunianus Biohorizon and records the upper part of the Main Alum Shale faunal turnover. Historical Note: these upper Main Alum beds were among the principal alum-working shales of the Whitby coast.

Bed W14 — Howarth Beds 65–71, Lower Cement Shales (1.85 m)

The Cement Shales begin with grey shale containing several rows of calcareous concretions and more resistant horizons than in the softer Main Alum Shales below. The nodules in this upper subdivision were formerly worked for cement manufacture. Ammonites: Hildoceras of the bifrons group with occasional Phylloceras heterophyllum and rare Lytoceras cornucopia. Other Fossils: belemnites remain common, and bivalves such as Nuculana and Gresslya occur. Interpretation: more calcareous offshore shale sedimentation, still fully marine, with repeated concretion growth.

Bed W15 — Howarth Bed 72 (lower part), Vortex Interval Of The Cement Shales (1.5 m)

The lower part of Bed 72 is grey shale with calcareous nodules belonging to the fibulatum–vortex part of the Bifrons Zone. Ammonites: Porpoceras cf. vortex, P. verticosum and Hildoceras of the bifrons group. Belemnites: several Acrocoelites and Simpsonibelus species remain characteristic. Interpretation: uppermost preserved Cement Shale below the highest preserved lower Toarcian strata at Whitby.

Bed W16 — Howarth Bed 72 (upper part), Crassum Interval Of The Cement Shales (2.5 m)

The uppermost preserved Whitby Mudstone at Whitby belongs to the crassum part of the Bifrons Zone. Grey shale with calcareous nodules yields Catacoeloceras crassum, Hildoceras semipolitum and Hildoceras of the bifrons group. The base of this unit at Whitby is a parastratotype for defining the Crassum Subzone in Howarth’s revised scheme. Interpretation: upper lower Toarcian offshore mud deposition immediately before the regional erosional break at the base of the Middle Jurassic.

Bed W17 — End-Lower Jurassic Omission Surface And Dogger Unconformity

At Whitby the Alum Shale Member is cut by a sharp erosional surface beneath the Dogger Formation. This surface records late Lower Jurassic uplift, gentle folding and erosion, which removed the uppermost Alum Shale as well as the higher Peak Mudstone and Fox Cliff Siltstone members that are preserved elsewhere in the basin. Derived ammonites, belemnites and phosphatic nodules in the overlying Dogger demonstrate the magnitude of the break, and large burrow systems pipe Dogger sediment downward into the shale beneath.

Dogger Formation (Middle Jurassic: Aalenian)

Bed W18 — Basal Dogger Ferruginous Sandstone / Ironstone (c. 0.75 m At East Cliff, But Locally Channelled And Cut Out)

At Whitby East Cliff the Dogger is a coarse, sometimes pebbly, ferruginous sandstone or ironstone forming an inclined bench near the foot of the cliff. It contains berthierine (chamosite) ooids, reworked phosphate nodules and broken ammonite and belemnite fragments derived from the underlying Whitby Mudstone. Westward along the shore it may thin drastically or be almost entirely removed by sandstone-filled channels cut down from the Saltwick Formation above. Depositional Environment: shallow marine transgressive sandstone and ironstone laid down across an erosional surface after a major hiatus.

RAVENSCAR GROUP

Saltwick Formation (Middle Jurassic: Aalenian)

Bed W19 — Lower Saltwick Channel Complex And Whitby Plant Bed

The lower Saltwick Formation above the Dogger consists of grey mudstones, siltstones and yellow-grey sandstones of fluvial to estuarine aspect, with channel fills, plant debris and synsedimentary disturbance. Around Long Bight and the East Cliff section, sandstone-filled channels may cut deeply enough to thin or almost remove the Dogger below. The fine sandstones and siltstones immediately above the Dogger contain abundant plant remains traditionally referred to as the Whitby Plant Bed, and large sandstone-filled root systems descend downward into the Dogger and even into the top of the Alum Shale. Interpretation: fluvial, floodplain and estuarine or delta-plain sedimentation following marine Dogger deposition.

Bed W20 — Unio Bed (0.05 m Skin On Fallen Blocks; c. 6.2 m Above The Dogger)

The Unio Bed is a thin reddish sideritic siltstone horizon lying about 6.2 m above the Dogger. It is most often recognised on fallen blocks rather than as a continuously clean in situ ledge and contains occasional freshwater bivalves traditionally called Unio. It is one of the best field datums in the lower Saltwick succession at Whitby and marks a definite freshwater influence within the mainly fluvial-deltaic sequence.

Bed W21 — Main Saltwick Fluvial Sandstones, Mudstones And Footprint Horizons (Total Saltwick Thickness About 30 m At East Cliff)

The main body of the Saltwick Formation at Whitby East Cliff consists of cross-stratified yellow-grey sandstones, grey mudstones and siltstones with erosive channel bases, plant remains, rootlets, local seatearth-like horizons and abundant evidence of non-marine deposition. Dinosaur footprints occur in fallen blocks from at least two horizons, one at the Unio Bed and another about 6 m higher, including tridactyl bipedal prints and parts of sauropod tracks; some tridactyl traces have been interpreted as swim traces. Depositional Environment: river channels, floodplain muds and vegetated overbank settings on a low-relief delta plain or paralic coastal plain.

Eller Beck Formation (Middle Jurassic: Aalenian)

Bed W22 — Eller Beck Marine Sandstones (c. 6 m)

The highest unit normally seen in the Whitby East Cliff section is the Eller Beck Formation, a package of orange-weathering marine sandstones resting above the non-marine Saltwick beds. This marks a renewed marine incursion into the Ravenscar coastal plain system and completes the lowest Middle Jurassic succession visible at Whitby. Interpretation: shallow-marine clastic deposition above the fluvial Saltwick Formation, showing rapid lateral and vertical environmental change during early Aalenian time.

Depositional Environment

The Whitby succession records a major shift from restricted offshore early Toarcian black-shale sedimentation into more oxygenated offshore mud deposition and then across a marked erosional break into Middle Jurassic shallow-marine, fluvial and marine-again conditions. The Mulgrave Shale Member, including the Jet Rock and Bituminous Shales, formed in oxygen-poor to anoxic offshore waters and yields laminated bituminous mudstones, jet, pyritized fossils and sparse benthos. The Alum Shale Member records somewhat less restricted offshore marine mud deposition, with more common concretions, widespread bivalves such as Dacromya ovum, richer ammonite zonation and the classic reptile-bearing alum shales of Whitby and Saltwick. After uplift and erosion at the end of the Lower Jurassic, the Dogger records shallow-marine transgression, the Saltwick Formation records fluvial to delta-plain and estuarine sedimentation with plants and dinosaur footprints, and the Eller Beck Formation records renewed marine flooding.

Total Thickness Covered Here: Approximately 55 Metres Of Middle Whitby Mudstone Formation Exposed In The Whitby East Pier–Saltwick Nab Section, Overlain By About 0.75 Metres Of Dogger Formation, 30 Metres Of Saltwick Formation And 6 Metres Of Eller Beck Formation In The East Cliff Composite Section

References

Howarth, M.K. (1962). The Jet Rock Series and the Alum Shale Series of the Yorkshire coast.
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, including the Whitby to Saltwick GCR account.
Benton, M.J. & Spencer, P.S. (1995). Fossil Reptiles of Great Britain, Whitby–Saltwick GCR account.
Dineley, D.L. & Metcalf, S.J. (1999). Fossil Fishes of Great Britain, Whitby Coast GCR account.
Fox-Strangways, C. & Barrow, G. (1915). The geology of the country between Whitby and Scarborough.
British Geological Survey Lexicon of Named Rock Units: Whitby Mudstone Formation, Mulgrave Shale Member, Alum Shale Member, Dogger Formation and Saltwick Formation.
Whyte, M.A. & Romano, M. on the Whitby–Saltwick Lower to Middle Jurassic coastal excursion and the Saltwick dinosaur footprint horizons.