Kettleness Fossil Hunting

1822–1828 – Young and Bird established the Yorkshire coast succession that includes Kettleness
One of the earliest major scientific milestones for Kettleness came with the classic work of Young and Bird on the Yorkshire Jurassic coast. Their studies helped establish the fossil-rich Lower Jurassic succession of this stretch of coast in the geological literature and laid the foundations for later work on the ammonites, ironstones and reptile-bearing beds of the Kettleness area.

1829 – John Phillips published the classic early account of the Yorkshire Lower Jurassic
Phillips’ work provided one of the key early frameworks for the Lower Jurassic of the Yorkshire coast, including the succession represented around Kettleness. This became one of the main starting points for later stratigraphic and palaeontological work on the area.

1848 – the skeleton later named Rhomaleosaurus cramptoni was excavated at Kettleness
Workers uncovered this large marine reptile in the Kettleness alum quarry. The original skeleton belongs to the National Museum of Ireland; the familiar London Natural History Museum display is a cast. The specimen became the basis for the species Rhomaleosaurus cramptoni.

1876 – Tate and Blake published sections that underpinned later work on the Kettleness succession
The studies of Tate and Blake became the basis for much of the later geological understanding of the Upper Pliensbachian and Lower Toarcian beds along this part of the coast. Kettleness is a separate exposure farther south-east along the Yorkshire coast.

1883 – a plesiosaur skeleton was found at Kettleness
Kettleness produced a notable plesiosaur discovery in 1883. This is one of the clearest dated fossil finds tied to the locality and helped build the site’s long reputation for marine reptile remains.

1892 – Fox-Strangways reviewed the classic early work on the coast
By the late nineteenth century, the geology and fossil-bearing beds of the Yorkshire coast had become important enough to be synthesised in Geological Survey work. This helped cement the scientific importance of the locality within the Yorkshire Jurassic succession.

1933 – Arkell highlighted the significance of the Yorkshire Lower Jurassic coast
Arkell’s work kept the Kettleness coast central to discussions of the British Lower Jurassic. By this time the area was already well known for its fossiliferous ironstones, ammonites and marine reptile remains.

1955 – Howarth produced the stratigraphic framework later used for the Kettleness beds
Howarth’s detailed work on the Yorkshire Lower Jurassic provided the framework for the beds exposed around Kettleness, including the Cleveland Ironstone succession and adjacent shales. His work underpinned much of the later modern interpretation of the coast.

1973 – Howarth documented the west and east Kettleness Grey Shale sections
Howarth mapped the separate foreshore exposures at Kettleness and included measurements from them in his detailed Yorkshire Grey Shale succession. His work recorded the ammonite-bearing nodule horizons and distinguished the faulted eastern exposure from the western reef, providing a firm basis for later correlation.

Modern understanding – Kettleness remains one of Yorkshire’s most productive localities for reptile remains
Today Kettleness is widely recognised as one of the most productive fossil localities in Yorkshire for reptile remains, while also being well known for ammonites from the Cleveland Ironstone and associated beds. Its importance lies in combining strong collecting potential with major stratigraphic significance in the Yorkshire Lower Jurassic succession.

The KB identifiers are guide-only display labels. Thicknesses explicitly described below as the standard Yorkshire scheme are correlation context, not local Kettleness measurements. Kettleness has its own Howarth (1955) bed numbers: the BGS framework places the top of the Cleveland Ironstone at Bed 24 here, unlike Bed 56 at the Staithes type section. Locality-specific member exposures are independently documented in the BGS sample table, but a full modern measured bed-by-bed Kettleness log is not established by these regional values.

Section Architecture

Kettleness is not a single clean vertical cliff log. The lower part of the succession is best understood from foreshore reefs on the western and eastern sides of Kettleness, whereas the higher Whitby Mudstone succession was historically exposed in the old alum quarries and in the modified upper cliff. Nineteenth-century alum and jet working, later cliff recession and repeated landslip have drastically altered the natural profile, so the locality must be treated honestly as a composite of foreshore, slip debris and old quarry faces rather than as one uninterrupted modern section.

Numbering Note

Formal published bed numbers exist for parts of the Kettleness succession, especially in Howarth’s classic Yorkshire Pliensbachian and Grey Shale studies, but the modern exposure is too altered to present every bed as a simple field log. The breakdown below therefore uses formal members and named horizons throughout, retaining published bed references where they are securely tied to Kettleness or to the standard Yorkshire coastal Lower Jurassic scheme used to correlate this coast.

LIAS GROUP

Cleveland Ironstone Formation (Upper Pliensbachian)

Kettleness Member

Uppermost Ironstone — Local Bed 24

The upper ironstone is present in the local foreshore succession. Howarth’s 1973 map and account identify it by the Kettleness-section number 24; the BGS framework places the top of the Cleveland Ironstone at that bed. This local numbering is not the Staithes 41–57 sequence previously reproduced here.

Regionally the Cleveland Ironstone includes marine mudstone, siltstone and berthierine–siderite ironstone, with the Pecten and Main seams in the Kettleness Member. Those regional seam descriptions explain the rock types, but a complete set of Staithes seam thicknesses and rare ammonite records is not assigned to this locality without a corresponding local log. The original detailed claims are retained in the revision archive rather than republished as verified local measurements.

Whitby Mudstone Formation (Lower Toarcian; Basal Boundary Beds At Kettleness Include The Latest Pliensbachian Transition)

Grey Shale Member

Measured Grey Shale Composite And Exact Local Provenance

Howarth’s 1973 measured composite explicitly includes Runswick and west/east Kettleness for Beds 1–18, and east Kettleness for Beds 18–32. He describes little lithological variation, but shale thickness may vary by up to 25%. The following are his published composite measurements, not a claim that each bed was independently measured at every named reef. His total for Beds 1–32 is 13.56 m. Specimen-locality codes are respected where fossils are named below.

Howarth records the whole Grey Shale succession on the west reef at NZ 829159, although Beds 22 and 24 were difficult to trace. East Kettleness has a faulted, south-dipping synclinal exposure around Fillet Tail Dump, approximately NZ 836160–839158. These are separate mapped source sections, not a single cliff log.

Boundary Beds 25–28 — Older Kettleness Numbering

The BGS formal Cleveland Ironstone top is at local Bed 24. Howarth’s older Ironstone Series continued above it through Bed 25, 0.33 m sandy grey shale with basal nodules and Pleuroceras hawskerense; Bed 26, the 0.15 m laminated bituminous Sulphur Band; Bed 27, 0.46 m sandy shale; and Bed 28, a 0.05 m row of calcareous nodules with bivalves. The 1973 Grey Shale numbering restarts at 1 above Bed 28. These historical boundaries are not equated with the modern formation boundary.

Howarth 1973 Bed 1 — 0.51 m

Grey shale.

Howarth 1973 Bed 2 — 0.53 m

Dark-grey laminated bituminous shale; a parting may occur 0.20 m below the top. A basal nodule yielded Lytoceras at east Kettleness.

Howarth 1973 Bed 3 — 0.08 m

Continuous calcareous/sideritic mudstone, red-weathering; Protogrammoceras paltum is recorded from Runswick and east Kettleness, with indeterminate Dactylioceras at east Kettleness.

Howarth 1973 Bed 4 — 0.36 m

Grey shale.

Howarth 1973 Bed 5 — 0.05 m

Small rounded calcareous nodules; no ammonites recorded in the source collection.

Howarth 1973 Bed 6 — 0.53 m

Grey shale.

Howarth 1973 Bed 7 — First Red Nodules — 0.08 m

Calcareous and sideritic nodules, red-weathering; some contain belemnites and rarer bivalves.

Howarth 1973 Bed 8 — 0.41 m

Grey shale.

Howarth 1973 Bed 9 — Second Red Nodules — 0.05 m

A separate red-weathering concretion row of the same reported type.

Howarth 1973 Bed 10 — 0.25 m

Grey shale.

Howarth 1973 Bed 11 — Third Red Nodules — 0.05 m

A separate red-weathering concretion row.

Howarth 1973 Bed 12 — 0.30 m

Grey shale.

Howarth 1973 Bed 13 — Fourth Red Nodules — 0.05 m

A separate red-weathering concretion row.

Howarth 1973 Bed 14 — 0.23 m

Grey shale.

Howarth 1973 Bed 15 — Fifth Red Nodules — 0.08 m

A separate red-weathering concretion row.

Howarth 1973 Bed 16 — 0.20 m

Grey shale.

Howarth 1973 Bed 17 — Sixth Red Nodules — 0.08 m

Frequent calcareous/sideritic nodules with red exteriors; belemnites and occasional bivalves, without recorded ammonites.

Howarth 1973 Bed 18 — 0.38 m

Grey silty shale; a central row contains small nodules and calcified Dactylioceras crosbeyi clusters. Records include Runswick and both Kettleness exposures.

Howarth 1973 Bed 19a — 0.41 m

Grey shale; the basal 0.10 m is closely laminated and bituminous, with pale sandy masses about 0.30 m above its base.

Howarth 1973 Bed 19b — 0.05 m

Grey shale with red-weathering flat lenticular concretions and calcified D. clevelandicum clusters; recorded at Runswick and both Kettleness exposures.

Howarth 1973 Bed 19c — 0.81 m

Grey shale above the Clevelandicum horizon.

Howarth 1973 Bed 20 — 0.15 m

Two close rows of red-weathering calcified lenses; D. tenuicostatum is documented in the east-Kettleness collection.

Howarth 1973 Bed 21 — 0.76 m

Grey shale with occasional calcareous nodules; the species is documented from Runswick.

Howarth 1973 Bed 22 — 0.08 m

Small spherical nodules, commonly enclosing D. tenuicostatum; records include Runswick and east Kettleness.

Howarth 1973 Bed 23 — 0.38 m

Grey shale with occasional rounded calcareous nodules.

Howarth 1973 Bed 24 — 0.08 m

Another spherical nodule row with D. tenuicostatum; records include Runswick and east Kettleness.

Howarth 1973 Bed 25 — 0.61 m

Grey shale with occasional rounded nodules.

Howarth 1973 Bed 26 — 0.05 m

Thin flat red-weathering calcareous nodules; D. tenuicostatum is documented at east Kettleness.

Howarth 1973 Bed 27 — 0.61 m

Grey shale; rare flattened D. tenuicostatum in the composite account.

Howarth 1973 Bed 28 — 0.23 m

Two adjacent rows of large hard calcareous doggers, with less pyrite than Bed 30. D. semicelatum is documented at east Kettleness; the cited Cenoceras record is from Port Mulgrave, not assigned to these localities.

Howarth 1973 Bed 29 — 1.07 m

Grey shale with granular pyrite, especially below, and occasional flattened ammonites in the composite account.

Howarth 1973 Bed 30 — 0.10 m

Very hard calcareous doggers with abundant pyrite and D. semicelatum; east-Kettleness records are explicit.

Howarth 1973 Bed 31 — 2.13 m

Grey shale with crushed D. semicelatum, particularly near its middle; east-Kettleness specimens are recorded.

Howarth 1973 Bed 32 — 1.83 m

Grey shale, locally bituminous, with occasional flat upper nodules and shell beds at its base and 0.10 m above. Tiltoniceras antiquum is recorded at east Kettleness; the full faunal list in the paper combines several localities.

Mulgrave Shale Member

Bed KB6 — Jet Rock, Equivalent To The Lower Mulgrave Shale Member (Howarth Beds 33–40; c. 7.2 m In The Standard Yorkshire Section)

The Jet Rock is the classic lower bituminous division of the Mulgrave Shale Member and is represented at Kettleness on the foreshore, in fallen nodules and historically in old workings. It consists of dark grey to black bituminous and pyritic mudstone with enormous calcareous concretions, including the Cannon Ball Doggers, Whalestones, Curling Stones, Top Jet Dogger limestone and Millstones. The lower third of the member is the principal jet-bearing interval, formed from highly compressed fossil wood. Yorkshire Jet Rock Correlation Fauna, Not An Independently Verified Kettleness Bed List: Eleganticeras elegantulum, Cleviceras exaratum, C. elegans, Harpoceras serpentinum, Hildaites murleyi, Dactylioceras spp. and Phylloceras heterophyllum, together with abundant belemnites. Interpretation: laminated, organic-rich offshore mud deposited under strongly oxygen-restricted to anoxic bottom conditions during the early Toarcian environmental crisis; this is one of the most distinctive black-shale facies in the British Jurassic.

Historical West Kettleness Exposure Limits

Howarth’s west Kettleness account distinguishes a foreshore interval from the top of Bed 32 to the lower part of Bed 38, with Beds 39–40 higher in the cliff. This historical exposure evidence is not a complete current measured foreshore log. The standard Yorkshire package thickness and broadly correlated fauna must remain separate from these specifically documented exposure limits.

Bed KB7 — Upper Mulgrave Shale Member: Bituminous Shales And Ovatum Bed

The fossil association below provides Yorkshire reference context for this stratigraphic package; it is not an independently verified Kettleness bed-by-bed collection list. Above the Jet Rock the member continues in dark bituminous shale with scattered rows of pyritic or sideritic concretions and local shell-rich levels. The shale is still organic-rich and dark, but generally less dominated by giant concretionary horizons than the Jet Rock below. The top is marked by the Ovatum Bed, a double row of large sideritic concretions and pyritic masses that forms one of the key markers in the upper Mulgrave. Published Yorkshire Reference Fauna: Harpoceras of the falciferum group, including forms historically referred to H. mulgravium, Dactylioceras spp., Nodicoeloceras incrassatum and Ovaticeras ovatum; belemnites include Youngibelus tubularis, Y. simpsoni, Simpsonibelus dorsalis and species of Acrocoelites. Dense belemnite concentrations or “battlefields” are typical at some levels. Interpretation: continuation of the lower Toarcian black-shale regime under persistently dysoxic to anoxic conditions, with the Ovatum Bed marking the top of the most strongly bituminous facies.

Alum Shale Member

Bed KB8 — Hard Shales, Lower Alum Shale Member

The fossil association below provides Yorkshire reference context for this stratigraphic package; it is not an independently verified Kettleness bed-by-bed collection list. The Hard Shales form the lower part of the Alum Shale Member and are composed of grey non-bituminous shales with scattered calcareous nodules and pyritic masses. Compared with the Mulgrave Member below they are less richly bituminous, less perfectly laminated and more hospitable to benthic and nektonic faunas, though still deposited in quiet offshore waters. Published Yorkshire Reference Fauna: Dactylioceras commune, D. temperatum and Hildoceras of the lusitanicum group, with belemnites and subordinate bivalves. Interpretation: the first stage of recovery from the peak black-shale facies below, with less severe bottom-water restriction but continued fine-grained offshore sedimentation.

Bed KB9 — Main Alum Shales

The fossil association below provides Yorkshire reference context for this stratigraphic package; it is not an independently verified Kettleness bed-by-bed collection list. The Main Alum Shales are softer, less calcareous and generally paler-weathering than the Hard Shales or Cement Shales, and they formed the principal raw material for the alum industry that transformed the Kettleness cliffs into their present man-modified profile. These shales are grey when fresh but weather pale grey, buff and yellow in the quarry faces. Published Yorkshire Reference Fauna: Dactylioceras commune and D. athleticum, Frechiella subcarinata, Pseudolioceras lythense, Peronoceras fibulatum, P. turriculatum, P. subarmatum and Hildoceras of the bifrons group, with common Nuculana ovum, Gresslya, belemnites and large driftwood logs. Vertebrates: much of the classic Kettleness marine reptile material is traditionally attributed to the lower Bifrons-Zone “communis” levels within the Main Alum Shales and the transition into the Cement Shales. Interpretation: offshore mud deposition under improving but still fluctuating oxygenation, with the shale chemistry suitable for alum extraction because of its relatively low calcium carbonate content.

Bed KB10 — Cement Shales And Upper Alum Workings

The fossil association below provides Yorkshire reference context for this stratigraphic package; it is not an independently verified Kettleness bed-by-bed collection list. The Cement Shales form the harder and more calcareous upper part of the Alum Shale Member. They contain abundant beds and rows of calcareous concretions, many formerly burnt for Roman cement, and they are more resistant than the softer Main Alum shales beneath. Published Yorkshire Reference Fauna: Hildoceras of the bifrons group, Porpoceras of the vortex group, Catacoeloceras crassum, belemnites and abundant Nuculana ovum. Vertebrates: plesiosaurs and other marine reptiles are historically especially common in the Main Alum and Cement Shales at Kettleness, and at least some classic specimens are thought to have come from the Cement Shales or from the uppermost Main Alum–lowest Cement interval. Interpretation: continued offshore marine mud deposition with stronger concretion growth, increasing calcareous content and repeated pauses in sedimentation, before the younger Toarcian succession was cut out by the overlying Dogger erosion surface.

Dogger Formation (Aalenian)

Bed KB11 — Dogger Unconformity And Ferruginous Cap, Where Preserved

Where the natural upper contact survives, the Whitby Mudstone is cut by a sharp erosional unconformity beneath the Dogger Formation. The Dogger is a ferruginous sandstone or ironstone of highly variable thickness and lithology, and on this part of the coast it commonly rests directly on the Alum Shale Member because the higher Toarcian Peak Mudstone and Fox Cliff Siltstone members are absent. At Kettleness much of this upper contact has been altered, removed or obscured by old quarrying and subsequent cliff retreat, but the regional stratigraphic meaning is clear: a major break and reworking surface at the base of the Middle Jurassic succession.

Exposure And Preservation Note

Kettleness is one of those Yorkshire localities where the industrial and geological histories are inseparable. The upper cliffs are partly artificial quarry faces cut into the Alum Shale Member, the original headland has been greatly reduced by extraction and landslip, and much fossil material is now recovered from fallen nodules, slip debris and foreshore blocks rather than from an intact in-situ face. The page therefore emphasizes securely recognizable horizons and member-level packages rather than pretending that every historic fossil can still be tied to a neat modern exposure.

Depositional Environment

The Kettleness succession records a major shift from the uppermost late Pliensbachian ironstone shelf into the lower Toarcian mudrock basin of the Cleveland Basin. The Kettleness Member of the Cleveland Ironstone Formation was laid down as storm-influenced marine mud and silt cycles capped by berthierine- and siderite-rich ironstones formed during prolonged pauses in clastic sedimentation and repeated shallow-water reworking. The Grey Shale Member records renewed deepening and quieter offshore mud accumulation during the Pliensbachian–Toarcian transition. The Mulgrave Shale Member then represents the famous lower Toarcian organic-rich black-shale facies, deposited under strongly oxygen-restricted bottom waters during the Toarcian Oceanic Anoxic Event, with giant concretions and horizons of compressed fossil wood that formed jet. The Alum Shale Member records a gradual return to less strongly restricted offshore conditions, though still within a quiet muddy sea, with Hard Shales, softer Main Alum Shales and more calcareous Cement Shales marking a long recovery interval before erosion and condensation at the base of the Dogger Formation.

Total Thickness Note

The exact modern thickness visible at Kettleness cannot be measured as one clean section because quarrying and landslip have destroyed the original continuous face. What can be stated securely is that the Howarth’s 1973 Grey Shale composite is 13.56 m thick and explicitly includes Kettleness measurements, and Kettleness also exposes the overlying Mulgrave and Alum Shale members through many additional tens of metres up to the Dogger unconformity, together with the uppermost few metres of the Kettleness Member below.

Local Alum-Quarry Reference Horizons

Howarth’s Kettleness quarry account identifies the Ovatum Band near the eastern quarry floor, a red dogger line roughly 15 feet above it, and ammonite-bearing nodules in the upper part of Bed 49 and lower part of Bed 51. The reported Dactylioceras commune and Hildoceras sublevisoni occurrences belong to that specific quarry account. They should be kept distinct from a full Whitby or Port Mulgrave bed-thickness column.

References

Howarth, M.K. (1955). The ammonite zones of the uppermost part of the Middle Lias of the Yorkshire coast.
Howarth, M.K. (1962). The Jet Rock Series and the Alum Shale Series of the Yorkshire coast.
Howarth, M.K. (1973). The stratigraphy and ammonite fauna of the Upper Liassic Grey Shales of the Yorkshire coast.
Howarth, M.K. (1992). The Ammonite Family Hildoceratidae in the Lower Jurassic of Britain.
Howard, A.S. (1985). Lithostratigraphy of the Staithes Sandstone and Cleveland Ironstone formations (Lower Jurassic) of north-east Yorkshire.
Cox, B.M., Sumbler, M.G. & Ivimey-Cook, H.C. (1999). A formational framework for the Lower Jurassic of England and Wales.
Page, K.N. (2004). Staithes to Port Mulgrave and Boulby Quarries, in British Lower Jurassic Stratigraphy, Geological Conservation Review Series 30.
British Geological Survey Lexicon of Named Rock Units: Cleveland Ironstone Formation, Kettleness Member, Grey Shale Member, Mulgrave Shale Member, Alum Shale Member and Dogger Formation.
Jarvis, I. and co-authors (2024) on the upper Pliensbachian–middle Toarcian chemostratigraphy of the Cleveland Basin and the Toarcian Oceanic Anoxic Event.
Benton, M.J. & Taylor, M.A. (1984), Benton, M.J. & Spencer, P.S. (1995), and Vincent, P. & Smith, A.S. (2009) on the Kettleness marine reptile material and its source horizons.
English Heritage / RCHME survey reports on the Kettleness alum works for the historic modification of the cliff section.