When beach conditions are favourable, Tankerton can be a rewarding place to search the London Clay foreshore. Fish, crustaceans, molluscs and shark teeth occur loose or inside nodules, while scouring can reveal much larger patches of clay. The shore changes continually, and finding productive material depends as much on safe access and recent exposure as on a careful eye.
FIND FREQUENCY: ♦♦♦♦♦ – A diverse fauna occurs along the roughly 2.2 km shore between western Tankerton and Long Rock, but success varies greatly with exposure.
CHILDREN: ♦♦♦ – Convenient shore access suits a supervised visit; deep silt and clay make the lower foreshore unsuitable for unsupervised exploration.
ACCESS: ♦♦♦♦ – Paths and steps lead from the seafront to the promenade and beach. Reaching scattered clay patches can still involve a long walk.
TYPE: – Fossils occur on sand and silt, in patches of exposed London Clay and in loose phosphatic nodules.
DIRECTIONS
♦ Follow the A299 towards Herne Bay and take the Herne Bay exit, joining the A2990 left at the roundabout.
♦ At the next roundabout turn right, then left at the junction onto the B2205. Follow it through Studd Hill towards the seafront, continuing along Marine Parade.
♦ The original guide favoured the eastern seafront parking, with the main car park farther along as an alternative. Use a legal space on the Marine Parade/Marine Crescent approach and observe current signs and payment conditions.
♦ Use established paths and steps across the slopes to the promenade and beach; avoid trampling the protected grassland.
♦ Locality reference: 51.36568°N, 1.04790°E.
FOSSIL HUNTING
Search loose nodules and naturally weathered material on firm sand or silt around exposed clay patches. Nodules may remain visible even when the clay itself is covered. Compared with beaches that have extensive shingle, tiny teeth can be harder to spot here, while larger fossils or nodule-contained remains are more conspicuous.
The original field account found productive lower-shore material within roughly 900 m of Long Rock and described the uppermost 10–15 m of beach as especially silty. These are observations of former conditions, not fixed collecting zones: sand, mud and nodule concentrations move, and the safest accessible patches may be elsewhere on a visit.
Recorded fossil groups include fish, sharks, rays, crinoids, gastropods, bivalves and crustaceans. Fossiliferous nodules can preserve delicate remains beneath their surface; inspect them carefully without indiscriminate splitting. Former whole-site species counts are not a guide to what a visitor should expect to find.
Tankerton specimens include the revised crab Dromilites belli and the mantis shrimp Heterosquilla tankertonensis, described in 2026. These are important scientific records rather than everyday finds. The type discovery of Hyracotherium leporinum belongs to neighbouring Studd Hill.
At the eastern end, much younger gravel and brickearth have yielded large-mammal remains in the Tankerton–Swalecliffe area. Keep these separate from Eocene fossils and record the original position and surrounding sediment of any bone. Loose shore material cannot always be assigned to a precise bed.
The original field account additionally records foraminifera, bryozoans, worms and other trace fossils, nautiloids, and rare turtle, snake and bird remains. These historical groups describe the wider fauna without implying that such finds are common or that the list is exhaustive.
A chronological record of fossil discoveries, geological research and conservation milestones associated with Tankerton.
1831 – Copperas industry documented
Samuel Lewis recorded copperas works on the Tankerton shore. Pyrite collected from the London Clay was used to produce green vitriol, linking coastal erosion and mineral collecting with the town’s industrial history.
1926 – Brickearth and gravel fossils investigated
F. H. Worsfold published a detailed account of the Tankerton Bay–Swalecliffe deposits, helping distinguish fossil mammals and land-shell horizons in the younger coastal cover from the Eocene London Clay below.
1953–1955 – Quaternary sections and faunas recorded
J. N. Carreck and M. P. Kerney added observations of mammal-bearing gravel, a land-shell bed and younger reworked deposits east of Tankerton. Their records preserve detail of sections later concealed by coastal protection.
2017 – Crab type material revised
A Tankerton foreshore specimen was included as a paratype of Dromilites belli. The revision separated this species from material historically confused with Dromilites bucklandii.
24 January 2026 – Mantis-shrimp holotype collected
A partial fossil tail recovered loose at Tankerton became the holotype NHMUK PI In 66760. Because it was not found in place, its horizon remains the local B1/B2 interval.
29 September 2026 – Heterosquilla tankertonensis described
The new mantis shrimp was named for Tankerton and described using the holotype and additional material from Tankerton and Seasalter. It added a rare crustacean to the documented fauna of these north Kent shores.
References
Holmes 1981, Geology of the country around Faversham, Sheet 273
Veitch 2026, A new species of mantis shrimp from the London Clay of Kent
Van Bakel and colleagues 2017, Eocene dromiid crabs revised: figured type specimens
GEOLOGY
Tankerton’s early Eocene London Clay is an ancient marine deposit beneath a much younger, changing beach. Fine sediment accumulated on the sea floor and now forms clay that is blue-grey when fresh and brown where weathered. The formation belongs to the Thames Group, and the local collecting interval covers informal Division B1 and lowermost B2 within the Aveley Member. Regionally, this member is predominantly silty clay with discontinuous concretions and some finer sandy or micaceous partings.
The platform extends beneath modern sand and silt, although it usually appears as separate exposed patches. Scouring removes parts of this cover and releases harder nodules and mineralised fossils from the clay; subsequent tides can move them again. Phosphatic nodules, carbonate concretions and pyrite therefore become conspicuous on a shore where little fresh clay is visible. Their concentration on the present beach does not necessarily mark a single nodule bed still in its original position.
The marine fauna includes crinoids, molluscs, fish and crustaceans. The crinoid Isselicrinus subbasaltiformis helps constrain the B1–lowermost B2 interval, while fossil-bearing nodules can preserve delicate animal remains. Correlation from a characteristic fossil is different from tracing a physical bed: the 2026 study of Tankerton mantis-shrimp material retains an overall B1/B2 provenance for its ex-situ specimens rather than assigning each to a particular division.
Towards eastern Tankerton and Swalecliffe, younger gravel, brickearth and land-shell horizons record a separate Quaternary landscape. Large-mammal remains belong to this younger record, and some still later deposits include reworked sediment and midden debris. The historical sections vary laterally and many were hidden by coastal works by 1959. They cannot be combined into one accessible stack at modern Long Rock, nor can a loose bone be dated simply by the London Clay beneath the beach.
Detailed geology and stratigraphy of Tankerton.
THAMES GROUP
The early Eocene marine deposits belong to the Thames Group. The units described here are the beds represented at this collecting locality; the complete regional group is not exposed on this shore.
London Clay Formation
Fine marine sediment forms blue-grey clay when fresh and brown clay where weathered. Carbonate concretions, phosphatic nodules and pyrite occur within the clay, but they are different materials: a loose nodule is not itself a formal bed and does not establish the exact horizon of a beach find.
Aveley Member
The B divisions of the London Clay lie within the Aveley Member in the current BGS framework. Its regional character is mainly silty clay with discontinuous claystone concretions; some levels contain finer sandy or micaceous partings. B1 and B2 are informal subdivisions within this framework, rather than formal members. No complete member thickness is implied for this foreshore.
Division B1
The lower part of the collecting interval belongs to B1. The crinoid Isselicrinus subbasaltiformis supports the local B1–lowermost B2 assignment, but beach specimens are commonly loose and cannot all be given a finer level. Numerous nodule concentrations and clay patches become visible as sand and silt are removed; their exposure is episodic.
Lowermost Division B2 and the crinoid interval
The local record extends into B2, although the 2026 mantis-shrimp paper explicitly leaves its ex-situ specimens at B1/B2 rather than assigning them to either subdivision. The crinoid is useful for correlation, but its occurrence does not establish a surveyed single bed across the whole beach.
Eastern Tankerton–Swalecliffe drift: basal gravel and brickearth
The historical coastal sections east of Priest and Sow Corner exposed a variable cover on an east-facing London Clay slope. Survey records describe about 1.1 m of brickearth and gravel in one fossil-bearing section, with mammal remains concentrated in its basal 0.3 m of bluish-grey clayey gravel. Other parts reached about 6 m of drift. These are historical, geographically scoped measurements, not today’s beach thicknesses.
Non-marine shell horizon and younger reworked deposits
Near the former Swalecliffe sewage works, the documented shell horizon was about 0.28 m of pale-grey clayey loam with subangular flints and calcareous nodules. Land molluscs were dominated by Succinea oblonga and Pupilla muscorum. Separate Holocene, human-reworked brickearth higher in the historical succession contained midden debris. The sections were reported concealed by concrete by 1959 and are not a modern exposed stack at Long Rock.
Historical lower grey brickearth east of Priest and Sow Corner
At TR 1298 6738, about 265 m east of Priest and Sow Corner, Holmes (1981) describes a 1.6 m grey argillaceous brickearth beneath the upper pebble-bearing layer. Iron-oxide mottling and scattered subangular flints accompanied dark, probably carbonaceous horizontal layers about 0.2 m thick, spaced at intervals of 0.3–0.45 m. Finds associated with the younger drift included heated flints, charcoal and pottery fragments, indicating midden debris. The memoir interprets pre-existing brickearth as disturbed and rearranged by people; this is not an undisturbed Eocene fossil bed.
Historical upper pebble-bearing brickearth
At the same historical east-Tankerton/Swalecliffe exposure, 0.75 m of brickearth containing flint pebbles of apparently recent beach origin lay above the 1.6 m grey argillaceous brickearth. The two layers should remain distinct in the historical account. Carreck reported that these cliff sections were entirely concealed by concrete by 1959, so neither layer is presented as an exposure available today.
Worsfold’s deeper blue-grey brickearth record
Holmes also preserves Worsfold’s 1926 observation of worked flints and woolly-rhinoceros teeth, Coelodonta antiquitatis, in blue-grey brickearth about 3.7 m below ground level on the low cliff, beneath a shell bed approximately equivalent to the memoir’s nearby land-shell horizon. The depth refers to that historical cliff locality, not to a continuous surveyed layer across modern Tankerton beach, and cannot be combined directly with the separate sections farther east or west.
References
BGS Lexicon: London Clay Formation
BGS Lexicon: Aveley Member
Aldiss 2014, Palaeogene stratigraphical framework, OR/14/008
Veitch 2026, A new species of mantis shrimp from the London Clay of Kent
UK Fossils, Tankerton (field inspection 2012)
Holmes 1981, Geology of the country around Faversham, Sheet 273
SAFETY
The broad flat foreshore can flood behind a collector. Check local tides and leave while a firm landward route remains open; do not follow receding water into soft channels or deep silt.
Clay and mud can trap walkers and make even a short return difficult. Keep children close on firm upper-shore ground and avoid isolated lower-shore exploration.
EQUIPMENT
Bring suitable footwear, a hand lens, separate specimen bags or rigid boxes, tide information and a charged phone. Routine loose collecting needs no hammer.
CLEANING AND TREATING
Keep phosphatic nodules whole in the field and wrap them individually. Exposed limbs or bones may continue beneath apparently blank matrix. Begin with a soft brush and stop if the fossil or its matrix moves with the dirt. Hard nodules can require fine mechanical preparation under magnification by an experienced preparator.
Avoid household acids, bleach and routine varnishing. Pyritic specimens need appropriate cleaning followed by dry, stable storage and regular checks for powdering, cracking or acidic decay. Do not seal wet material into long-term storage. Keep potentially important finds unprepared until a specialist has examined them.
IDENTIFY YOUR FINDS
Need help identifying a fossil? Share clear photos, where you found it and its size with the community.
FURTHER READING
Deposits: Seeds from the London Clay (regional background)
Deposits: Crystals and minerals of the London Clay (regional background)
Veitch 2026, A new species of mantis shrimp from the London Clay of Kent
Van Bakel and colleagues 2017, Eocene dromiid crabs revised: figured type specimens
Holmes 1981, Geology of the country around Faversham, Sheet 273
BGS Lexicon: Aveley Member
Canterbury City Council, Tankerton Coastal Park Management Plan 2025–2032
ACCESS RIGHTS
Tankerton Slopes SSSI protects sensitive grassland and plants. Other coastal designations, particularly around Long Rock, have different boundaries. Keep to established access paths, avoid damaging the slopes and give feeding or roosting birds space.
Collect conservatively from small loose material. Do not dig into slopes, clay platforms or sea defences; obtain the relevant agreement for intrusive work.
It is important to follow our ‘Code of Conduct’ when collecting fossils or visiting any site. Please also read our ‘Terms and Conditions’.
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