On the southern side of the Isle of Sheppey, Elmley Hill offers a quiet but demanding introduction to the London Clay. Lobster and fish remains occur in phosphatic nodules, with other fossils in pyritic shingle. Finds can be sparse, the walk is long and the shore is muddy; arrange reserve-manager permission before leaving the marked trail to collect.
FIND FREQUENCY: ♦♦♦ – Lobster fragments and fish remains occur in nodules, with occasional loose fossils in pyritic shingle. Productive patches are scattered.
CHILDREN: ♦ – The long walk, steep shore descent and sticky mud make this unsuitable for younger children.
ACCESS: ♦ – A remote shore reached by an embankment walk, historically about 3.2 km. Use the signed route and agree off-path access with the reserve manager.
TYPE: – Low London Clay cliffs and a muddy foreshore; nearby flood banks contain redeposited material with uncertain original provenance.
DIRECTIONS
♦ Approach the Kingsferry Bridge area by the old B2231 route. The original road approach used the docks turning before the bridge, crossing towards Sheppey and continuing towards the signed Elmley/Straymarsh Farm turn. Follow current road signs rather than reserve tracks.
♦ The signed Coast Path link from Swale Station crosses Kingsferry Bridge. Follow its current waymarks and the diversions around the gun club; do not use an informal low-tide shortcut.
♦ The earlier route followed the road past farm cottages to a waterside dead end, then an embankment path past gates, stiles and industrial remains, including concrete blocks, a slipway and foundations. That old stopping point is not a promise of parking: use only a legal signed space and keep farm and reserve access clear.
♦ Continue only on the marked trail towards Elmley Hill. Obtain the reserve manager’s agreement for any descent to the foreshore or off-path collecting; the historical shore approach involved a steep descent.
♦ Original locality reference: 51°22’16.1″N 0°45’52.8″E. This identifies the locality, not an authorised parking or descent point.
FOSSIL HUNTING
The natural foreshore contains patches of pyritic shingle and phosphatic nodules around low London Clay cliffs. The original field account recorded loose crinoid stems, shark teeth and crab remains in the shingle, and lobster fragments and fish remains in nodules. Search only safely accessible loose material where the reserve manager has agreed access and collecting.
The pyritic shingle extends south of the hill, but much of the lower shore is covered by sticky silt. A visible nodule beyond firm ground is not a reason to enter the mud. Crustacean fragments can be inconspicuous on an otherwise rounded nodule; retain the matrix rather than splitting a promising piece.
Martin Rayner recorded Cyclocorystes pulchellus, Portunites incerta and Hoploparia fragments. These support the importance of the crustacean fauna without making such finds common. Keep photographs, a precise locality record and an indication of whether a specimen came from natural shore material or redeposited ground.
The original guide also noted fossils weathering from dredged London Clay used in the embankment, especially its then more recently exposed first section. This is a historical observation, not permission to collect or dig into flood defences. Bank-derived material has uncertain original provenance and must be recorded separately.
The original field account also records worm tubes and other trace fossils, bivalves, gastropods and nautiloids. These broader historical observations are retained without treating its unrevised species list as a complete modern inventory.
GEOLOGY
Elmley Hill exposes early Eocene London Clay in a low cliff and intermittently visible foreshore platform. The blue-grey fresh clay and its browner weathered surface are the remains of fine marine sediment, contrasting with the much younger marsh deposits around the hill. The London Clay contains phosphatic nodules, carbonate septarian concretions and pyrite. These harder materials survive as the surrounding clay breaks down, helping to explain the mixture of nodules and pyritic shingle along the shore.
The natural exposure is assigned cautiously to the B1–B2 interval within the Aveley Member of the Thames Group. In the regional succession this member consists mainly of silty clay with discontinuous claystone concretions and some finer sandy or micaceous partings. At Elmley, crinoid material and the crustacean fauna helped Martin Rayner place the exposure near the B1/B2 boundary. They support a stratigraphic interval rather than proving a continuously exposed boundary or a measured sequence across the whole shore.
Weathering releases crinoid stem pieces, shark teeth and nodules containing crustacean or fish remains, after which tidal movement redistributes them. Modern silt can conceal both the clay and these concentrations. Rayner also described selenite weathering from a local cliff-base patch; this is a mineral occurrence within the weathering environment rather than a separately named fossil bed.
Human alteration complicates the natural sequence. Some clay appeared to overlie younger marsh sediment and may have been banked up artificially, while the old guide recorded fossils in dredged London Clay used in an embankment. Such material can contain genuine Eocene fossils without having come from the natural bed beside it. Distinguishing the low natural hill from redeposited bank material is therefore essential when interpreting the origin and age of a find.
Detailed geology and stratigraphy of Elmley Hill.
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.
B1–B2 interval and crinoid-bearing material
The older guide identifies B1 and B2. Martin Rayner’s field account independently placed the naturally exposed clay near their boundary using abundant crinoid material and its crustaceans, but presented that correlation cautiously. The low cliff and partly silt-covered platform contain both phosphatic and septarian nodules. This evidence supports an interval, not a measured succession or a sharply mapped B1/B2 contact.
Natural clay, imported clay and the selenite-bearing patch
Rayner distinguished in-situ London Clay with nodules from stretches where clay appeared to overlie younger marsh sediment and might have been artificially banked up. He also recorded a local concentration of selenite weathering from the cliff base. This is a mineral-bearing weathering occurrence, not an independently named stratigraphic bed. Unusual fossils from made ground cannot safely be used to extend the age of the natural exposure.
Marsh sediment and sea-defence made ground
Younger marsh deposits and artificial banks interrupt the low hills. Fossils seen in bank material during the 2012 inspection belong to redeposited London Clay; their original locality and horizon are uncertain. Foreshore collecting requires reserve-manager agreement wherever it involves leaving the permitted trail or entering restricted ground. Stay on the signed route unless that access and collecting permission has been established; never excavate flood defences or archaeological surfaces.
References
BGS Lexicon: London Clay Formation
BGS Lexicon: Aveley Member
Aldiss 2014, Palaeogene stratigraphical framework, OR/14/008
Martin Rayner, Elmley Hill: a small site with a big history (undated field account)
UK Fossils, Elmley Hill (field inspection 2012)
SAFETY
Deep sticky silt, a steep shore descent and the long return walk are the principal hazards. The original inspection recorded high water reaching the cliff base. Plan around local tides, maintain a firm return route and stay out of lower-foreshore mud.
Take a companion, a charged phone and sufficient water. Tell someone your route and expected return time. Do not enter closed gateways or descend from the path without the required permission.
EQUIPMENT
Bring sturdy footwear, a hand lens, specimen wrapping and rigid boxes, tide information, water and a charged phone. Routine examination of permitted loose material needs no hammer or digging tool.
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
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FURTHER READING
Deposits: Seeds from the London Clay (regional background)
Deposits: Crystals and minerals of the London Clay (regional background)
Martin Rayner, Elmley Hill: a small site with a big history (undated field account)
Aldiss 2014, Palaeogene stratigraphical framework, OR/14/008
Elmley Nature Reserve: current King Charles III England Coast Path guidance
ACCESS RIGHTS
Elmley is a National Nature Reserve. Remain on marked paths and nature trails, respect closed gateways and avoid disturbing birds. The Coast Path guidance excludes dogs from this sensitive section.
Walking access does not establish permission to leave the path or collect on reserve land. Obtain the reserve manager’s agreement before a collecting visit involving the shore or other off-path ground. Never excavate sea defences or archaeological surfaces.
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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