Seatown is one of Dorset’s classic fossil-hunting locations, offering rich Jurassic material set against some of the most dramatic coastal scenery on the south coast. However, it can be more dangerous than many nearby localities due to the exceptionally high and unstable cliffs, so care is always required. Fossils are commonly found loose along the foreshore, with some of the finest specimens—particularly ammonites—preserved within hard nodules that require careful preparation. During periods of strong coastal scouring, belemnites can occur in abundance across the beach.
FIND FREQUENCY: ♦♦♦♦ – There are a lot of fossils to be found at Seatown, given the right conditions. Most of the larger ammonites that can be found are within nodules but these are actually softer than the surrounding matrix, so you cannot just split them using hammers, they may need specialist preparation; the method depends on the fossil and matrix.
CHILDREN: ♦♦♦ – Seatown is suitable for families, but if you are planning to take children, care should be used and they should be kept well away from the base of the cliff. These are extremely high, sheer and crumble all the time.
ACCESS: ♦♦♦♦ – Accessibility to Seatown and the foreshore is excellent. There is a car park practically on the beach, with toilets and a pub next to it. It is also not a very long walk to the fossiliferous beds. Please be aware that the road is very narrow and not suitable for large vehicles.
TYPE: – The vast majority of the fossils are found on the foreshore at Seatown. Many are contained within small nodules that can be found among the pebbles. Fossils can also be found during scouring conditions on the foreshore clays. Search loose material on the open beach, well clear of the cliff base and landslips; do not approach the cliff layers or climb onto slips. This is also an excellent location for microfossils. Small samples of loose, detached clay associated with crinoid and belemnite debris can yield microfossils after scouring. Do not excavate the Belemnite Stone or other in-situ beds
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DIRECTIONS
♦ Seatown can be reached by following a narrow lane, just opposite the Castle Inn in Childeock. However, this road is not suitable for large vehicles, because of its width. Use the paid beach car park opposite the Anchor Inn; the pub describes this as independently owned, separate from its limited customer spaces. Check the posted opening and closing times before leaving the car, as the beach car park closes at dusk.
♦ The Anchor Inn reports seasonal lane restrictions from 24 May to 30 September. Always follow the current roadside signs and leave access clear; the dates alone do not establish that a particular roadside space is available or permitted.
♦ Golden Cap is on your right (west) from the car park at Seatown.
♦ There is a charge for parking at Seatown.
♦ Postcode to parking: DT6 6JU. Google maps link.
♦ What3Words: ///jumbo.dominate.litters
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FOSSIL HUNTING
The dramatic cliff of Golden Cap dominates the coastal scenery east of Charmouth and can be seen as the highest point on the south coast of Great Britain at Seatown. The cliffs and foreshore beneath and around Golden Cap is a favourite fossil collecting location, so it can be busy, particularly in the high season.
There are many types fossils that can be found at Seatown. The most common are ammonites. These can be found on the foreshore in the shingle, in nodules and within the Belemnite Stone Bed (when exposed). Belemnites are the second most common find, along with crinoids. Brachiopods, bivalves, fish remains and microfossils can also be found here and reptile remains less frequently.
From the car park, walk towards Golden Cap. The first part of the cliff of soft, precipitous clays is highly unstable and from hereon caution is advised. Keep clear of the base of these cliffs and be aware of falls, which can be sudden. These beds are the Green Ammonite Member, which contains limestone bands and scattered nodules. The latter may contain ammonites. Search only detached material washed onto the open foreshore, well away from the cliff and landslips; leave promising ammonite nodules intact for assessment. Ammonites in mudstone may be flattened or incomplete, whereas early-cemented nodules can preserve three-dimensional shells. Preservation varies, so a missing centre should not be assigned to one cause without examining the specimen.
After storms and with the clearance of shingle, the uppermost part of the Belemnite Marl Member is often exposed, with a profusion of belemnites. As you get closer to the middle of the cliff at Golden Cap, very fine shingle mixed with pyrites and clay can be found on the foreshore. Among the pebbles, fossils can be found, but this may involve a ‘hands and knees’ job. However, if you look carefully and you should make some finds. Look for ribbed ammonite whorl fragments and coiled outlines. Androgynoceras lataecosta is a characteristic Green Ammonite Beds record at Golden Cap; greenish calcite may fill chambers, but colour alone is not an identification.
Erosion of the soft mudstone around Golden Cap releases fossils onto the beach. Search the loose shingle and detached material on the open foreshore, well clear of the cliff and landslips. Do not enter soft mud or climb onto slipped ground; fresh falls may be followed by further collapse.
Only where tide, sea conditions and a clear return route allow you to keep well away from cliffs and landslips, search the open foreshore for nodules that have ammonites or for loose ammonites that have been washed out. You need to look at the nodules that contain parts of ammonites showing, as sometimes all you need is a tiny part of an ammonite to be revealed for it to turn out to be a beautiful specimen after preparation. Further along, a wide range of belemnites can also be found.
When scouring removes the beach cover, the Belemnite Stone and associated shell-rich beds may be exposed, with belemnites, crinoid debris, ammonites and small fossils. The Belemnite Stone is the upper part of the Belemnite Marl Member and is exposed as a prominent layer of limestone, packed with belemnites. The main outcrop of the Belemnite Stone is only seen at extreme low, spring tides. Loose belemnites can be lifted but do not hammer out any that are still in situ in the rock.
To find a nodule containing an ammonite, look for just a small part of the ammonite protruding. The nodules often look like a ‘Smartie’ sweet in shape. Such a nodule will require further work at home. You can find them all over the beach, but some contain fossils. However, do not try to split them using a geological hammer or chisel. You will break the fossil, as the fossil is softer than the nodule! These nodules need preparation with abrasives and an air pens and it might be best to find a fossil preparator who will undertake this work for you. Often, the cost of getting a nodule professionally prepared is worth the result!
Some of the most significant fossil discoveries and scientific milestones from Seatown and Golden Cap include the classic Green Ammonite Beds, the famous Belemnite Stone, important marine reptile finds, and the recently named ichthyosaur Xiphodracon goldencapensis.
1863 – John Day named the Green Ammonite Beds at Golden Cap and Seatown
One of the key scientific milestones for Seatown came when John Day used the term “Green Ammonite Beds” for the fossiliferous clays above the Belemnite Stone. These beds became one of the classic Lower Jurassic ammonite horizons on the Dorset coast and are still one of the main reasons Seatown is so well known to fossil collectors.
19th century onwards – the Belemnite Stone and Green Ammonite Beds became classic fossil horizons at Seatown
As collecting continued, Seatown became especially well known for the Belemnite Stone, rich in fossil belemnites, and for the overlying Green Ammonite Beds, which yield ammonites, belemnites, crinoids, bivalves, fish remains and occasional reptile material. These horizons helped establish Seatown as one of the classic fossil beaches on the Dorset coast.
2001 – Chris Moore discovered the Golden Cap ichthyosaur later named Xiphodracon goldencapensis
In 2001, Dorset collector Chris Moore discovered a near-complete ichthyosaur skeleton near Golden Cap between Charmouth and Seatown. The specimen proved to be exceptionally important because it preserved one of the most complete Pliensbachian ichthyosaurs yet found.
21 September 2008 – small ichthyosaur skull found at Seatown by Peter Quellin Taylor
A small ichthyosaur skull was collected from the beach at Seatown on 21 September 2008 by Peter Quellin Taylor. Although much smaller than the Golden Cap skeleton, it is a useful reminder that marine reptile material still turns up on the foreshore at Seatown.
2025 – Xiphodracon goldencapensis formally described
The ichthyosaur discovered by Chris Moore in 2001 was formally described in 2025 as Xiphodracon goldencapensis, the “Sword Dragon of Golden Cap”. It was especially significant because it was the first new genus of Early Jurassic ichthyosaur described from the region in more than a century.
MICROFOSSILS
Seatown is an excellent but often overlooked locality for microfossil collecting, with its Lower Jurassic clays and marls yielding a diverse and well-preserved assemblage of small fossils. Most microfossils here derive from Pliensbachian-aged deposits, particularly the Belemnite Marl Member, the Green Ammonite Mudstone Member, and the lower parts of the Eype Clay Member. These fine-grained sediments were laid down in relatively calm marine conditions, which favoured the preservation of delicate skeletal remains. The Belemnite Marl Member is especially productive, although it is usually buried beneath beach sand during the summer and is best accessed in winter or after periods of strong coastal scouring.
Collecting should be limited to loose material on the foreshore, never from the cliff itself. Soft grey to blue-grey marls found on the lower beach are ideal, particularly where small shell fragments are already visible. Even modest samples can yield large numbers of specimens, so only small amounts of sediment are needed. Fresh, unoxidised material tends to produce the best results, whereas heavily weathered or iron-stained marls are often less productive.
Once collected, the sediment can be processed by gently breaking it down in water, often with a small amount of detergent to help disaggregate the clay. After soaking, the material is washed through a fine sieve and allowed to dry naturally. The dried residue can then be examined under a low-power microscope or hand lens, where a wide range of microfossils can be picked out using a fine brush or pin.
Small samples can contain foraminifera, ostracods, tiny shells, echinoderm ossicles and fish debris. Under magnification, look for chambered foraminiferal tests, paired or bean-shaped ostracod valves, and patterned echinoderm fragments. Keep material from different matrices and horizons separate: the fossils in one sample are not necessarily representative of every Seatown member. Genus-level foraminiferal identification needs a suitable illustrated reference and should not be inferred simply from a broadly Jurassic appearance.
GEOLOGY
Golden Cap and the shore west of Seatown expose Lower Jurassic marine mudstones and sandstones, capped by much younger Lower Cretaceous Gault and Upper Greensand. An erosional unconformity separates these two successions. Folding, landslips and changing beach cover mean that the rocks are best understood as a composite section rather than an uninterrupted cliff-face log.
The lowest Jurassic interval relevant here is the upper Belemnite Marl Member of the Charmouth Mudstone Formation. Its upper beds can appear when shingle is stripped away. The Belemnite Stone marks the top of the member, followed by the Green Ammonite Member, with grey mudstone and distinctive limestone and nodule horizons.
Above this lies the Dyrham Formation. Its Eype Clay Member begins with the three resistant sandstone bands known as the Three Tiers; these are part of the member, rather than a separate formation beneath it. Higher in the Eype Clay are the Eype Nodule Bed and Day’s Shell Bed. The overlying Down Cliff Sand Member begins at the Starfish Bed, but its upper succession is truncated beneath the Cretaceous cap at Golden Cap.
The Gault Formation includes sandy mudstone above a basal pebbly interval. The overlying Upper Greensand Formation contains glauconitic sands and sandstones whose weathered yellow-brown colour gives Golden Cap its familiar appearance. These are distinct from the much older Jurassic sands below the unconformity. Regional formation thicknesses should not be read as the amount exposed at any one spot.
Detailed geology of Seatown and Golden Cap, including the published limestone, nodule and shell-bed markers of the Lower Jurassic succession and the unconformable Gault–Upper Greensand cap.
Locality And Section Architecture
This account follows Golden Cap and the adjoining Seatown shore. Jurassic beds change their height along the coast, and landslip and shingle obscure parts of the succession. It is a composite account, not a measured section through one cliff. Black Ven’s older bed-by-bed log is not transferred here.
Published Bed Numbers And Thicknesses
The Belemnite Marl numbers below are the established Lang bed numbers. Where numbered Green Ammonite markers are given, the later Phelps scheme is identified separately from the older Lang equivalents, following the BGS memoir. Unnumbered marker names are not invented bed numbers. Measurements are retained only with their locality or published-account scope; heights above a member base are not total visible cliff thicknesses.
LIAS GROUP
Charmouth Mudstone Formation — Lower Jurassic, Pliensbachian
Belemnite Marl Member — Upper Part
Alternations of paler and darker calcareous mudstone characterise this member. Only its upper beds are relevant to this part of the Seatown–Golden Cap shore. The full Stonebarrow reference section and its total thickness must not be read as exposed at Seatown.
Belemnite Bed — Lang Bed 120c
This upper marker is a dark, pyritic, friable mudstone containing concentrated belemnites and other shells. It is distinct from the overlying Belemnite Stone. The two are condensed fossil-bearing horizons rather than evidence that every part of the member is equally rich.
Bed 120d: a Golden Cap gastropod record. Cox’s 1928 account named Amberleya auricipitis in reference to Golden Cap and recorded its type material from Bed 120d: holotype G26320 and paratypes G26321–22. The shells were crushed, and the account does not identify a particular side of the headland or a precise foreshore position. This is a historical gastropod record from the upper Belemnite Marls, below the Belemnite Stone, distinct from the familiar ammonites of the overlying Green Ammonite Member. The name is retained as Cox used it.
Belemnite Stone — Lang Bed 121
The harder, concretionary limestone forms the top of the Belemnite Marl Member and provides a useful datum beneath the Green Ammonite Member. Local exposure varies with beach cover. The upper Belemnite Marl occurs below Golden Cap towards Seatown; the Stone and associated shell-rich beds are also documented between St Gabriel’s Mouth and Golden Cap.
Green Ammonite Member
The current BGS member name is Green Ammonite Member; Green Ammonite Beds and Green Ammonite Mudstone Member are also used in the literature. It comprises grey mudstone with several irregular carbonate horizons and becomes sandier towards its top.
Basal Contact Above The Belemnite Stone
The BGS Lexicon describes the contact as conformable. The 2011 BGS memoir instead records erosional scours and a hiatus, based on the detailed coastal work. Both accounts place the member above the Belemnite Stone; neither justifies assigning a measured duration to the break in this guide.
Lower Limestone — Phelps Bed 14; Lang Bed 123a
A discontinuous horizon of hard limestone nodules occurs in the lower part of the member. It helps divide the mudstone succession below the more conspicuous Red Band. Its nodular character must not be mistaken for one uniformly thick limestone sheet.
Red Band — Phelps Beds 21–23; Lang Bed 126
This middle marker comprises limestone and intervening mudstone, with red-brown weathering particularly conspicuous on exposed surfaces. It is an internal datum within the Green Ammonite Member, not a formation boundary. Fossils occur in the carbonates and associated mudstones.
Upper Limestone — Phelps Beds 32–34; Lang Bed 129
The higher carbonate marker includes shaly limestone separated by mudstone. It lies above the Red Band and below the sandier upper interval that leads towards the Three Tiers. These named horizons provide more useful field subdivision than an assumed evenly layered clay column.
Uppermost Pyritic Mudstone — Lang Beds 132b–c; Phelps Beds 40–41
Above the Upper Limestone, the mudstone becomes sandier upwards. The uppermost two metres are unusually dark and pyritic in the published coastal succession. The ammonite succession crosses into the lower part of the upper Pliensbachian before the lithological member boundary. The Three Tiers therefore do not define that age boundary.
Thickness Variation
Published accounts give differing values for the Green Ammonite succession at Golden Cap, and the member thins westwards towards Stonebarrow. No single fixed thickness is imposed in the chart. A regional maximum or a borehole thickness would not measure the section visible at this beach.
Dyrham Formation — Lower Jurassic, Pliensbachian
Eype Clay Member
Three Tiers — Basal Sandstone Interval
Three resistant, fine-grained calcareous sandstone beds alternate with softer sandy mudstone. They form the base of the Eype Clay Member and belong within the Dyrham Formation. They are not a separate formation beneath it. The full interval is reported as reaching about 9 metres beneath Golden Cap; individual sandstone beds are much thinner.
Micaceous Mudstone Above The Three Tiers
The main Eype Clay succession comprises blue-grey silty mudstone with mica, siderite nodules and occasional sandstone bands. Much of it weathers less conspicuously than the harder markers. West and the GCR describe about 60 metres of clay above the Three Tiers. Formal BGS usage includes the Three Tiers within the Eype Clay Member and gives an approximate 60-metre member thickness. These accounts use different descriptions of the interval; their figures should not be silently combined or treated as a measured thickness visible at one foreshore position.
Eype Nodule Bed And Local Sandstone Above
This horizon contains hard calcareous nodules and a varied shelly fauna. Beneath Golden Cap, the GCR account records a calcareous sandstone above the nodules, locally incorporating them at its base. The sandstone thins away eastwards, so that relationship should not be generalised into an identical bed at every neighbouring exposure.
Day’s Shell Bed — Upper Eype Clay Marker
A thin, laterally impersistent, shelly and crinoidal mudstone occurs near the member top. The BGS memoir specifically describes its fossil-rich exposure about 200 metres east of Seatown. This is an adjacent local reference for the upper member, not proof of a continuously visible shell bed across Golden Cap.
Down Cliff Sand Member
Starfish Bed — Base Of The Member
The Starfish Bed marks the change from Eype Clay into Down Cliff Sand. It is a fine sandstone horizon associated with the well-known brittle-star and starfish material of the wider Seatown–Eype coast. Its correct position is below the main Down Cliff Sand, not at the base of the younger Thorncombe Sand.
Muddy Sands And Laminated Beds
Fine, muddy sand and sandy mudstone follow above the basal marker, with harder sandstone lenses or bands. “Laminated Beds” is an older name for this interval. At Golden Cap, the upper part is removed beneath the Cretaceous overstep. The Margaritatus Stone and higher Jurassic succession from more complete sections eastwards are not added as though preserved here.
Local Conglomerate Horizon In The Down Cliff Sand
West’s Golden Cap account records a conglomeratic horizon about 19 metres above the Starfish Bed, with flat pebbles and rolled belemnites in clayey sand and sandstone nearby. This is a published local observation, not a uniform height or marker thickness to be imposed on every section. The upper succession remains truncated beneath the Cretaceous cover.
Major Jurassic–Cretaceous Unconformity
An erosional surface truncates the Jurassic succession before the younger marine deposits above it. The missing record includes much more than an ordinary bedding plane. Neither the chart nor this account attempts to turn the composite cliff into a complete record of all intervening Jurassic formations.
SELBORNE GROUP
Gault Formation — Lower Cretaceous, Albian
Basal Pebbly Interval
The basal Gault contains pebbles above the Jurassic erosion surface. Published Golden Cap accounts describe variation in this basal deposit, including local erosion and more than one pebbly horizon. It should not be depicted as a uniform, fixed-thickness band around the headland.
Sandy And Micaceous Mudstone
Finer, fossil-bearing sediment overlies the basal interval. The local Gault is sandier than many eastern English examples. Nearly 15 metres was reported near the centre of Golden Cap in the classic account cited by West, with less in other parts. The figure is a local published estimate, not a new measurement or the combined height of the Cretaceous cap.
Upper Greensand Formation — Lower Cretaceous, Albian
Foxmould Member
Glauconitic sand and sandstone weather from green-grey to yellow-brown. Cemented sandstone bodies occur within the softer sediment. This weathered unit contributes the characteristic colour of Golden Cap. Its boundary with sandy Gault is a lithological transition, unlike the much older erosional break beneath the Gault.
Higher Chert-Bearing Cap And Disturbed Summit Material
Chert-bearing beds occur higher in the cap, and the published local description notes slipped and broken chert material near the summit. This part is kept separate from the clean member description: a loose chert block or disturbed surface deposit does not establish a continuous measured upper member at its present position.
Using The Chart
The chart is a readable overview of this more detailed succession. It retains the correct youngest-to-oldest order without equating row height with thickness. A dash means no local thickness is assigned. Individual marker beds and the qualifications above remain important even when several are grouped into one chart row.
References
British Geological Survey (2011), South Dorset and south-east Devon and its World Heritage Coast
West, I. (2011), Golden Cap and Seatown: Geology of the Wessex Coast
BGS Lexicon: Belemnite Marl Member
BGS Lexicon: Green Ammonite Member
BGS Lexicon: Eype Clay Member
BGS Lexicon: Down Cliff Sand Member
BGS Lexicon: Gault Formation
BGS Lexicon: Upper Greensand Formation
BGS Lexicon: Foxmould Member
Simms et al. (2004), British Lower Jurassic Stratigraphy: Pinhay Bay to Fault Corner and East Cliff
Cox, L. R. (1928), The Gastropod and Lamellibranch Molluscs, pp. 233–245 in the Charmouth study.
SAFETY
Common sense should always be used when collecting at any location, and a good understanding of local tide times is essential. During the winter months in particular, this stretch of coastline can be extremely dangerous, as the sea often reaches the base of the cliffs. In storm conditions, the tide may not retreat at all, significantly increasing the risk of becoming cut off.
Beyond the headland, conditions on the return route may be hidden from view. Check local tide predictions and the sea forecast before setting out, allow a generous return margin, and turn back before narrowing beach or waves threaten your route. Low tide does not guarantee safe passage; do not wait for the tide to turn before assessing whether to return.
The cliffs at Seatown are exceptionally high and unstable, and rock falls are frequent. For your own safety, keep well away from the base of the cliffs at all times and never collect directly beneath them.
EQUIPMENT
Plenty of loose fossils can be found along the foreshore and shingle at Seatown, including belemnites, pyritic ammonites, and occasional reptile bones. The finest specimens are typically preserved within hard nodules known locally as “Greens”.
These nodules should not be broken open in the field. In most cases, the fossils inside are softer than the surrounding matrix, and attempts to split them with a hammer will almost certainly damage or destroy the specimen. Instead, promising nodules are best collected intact and taken away for specialist preparation using a method chosen for the fossil and its matrix.
For collecting on the open beach, a small trowel can help lift fossils from loose shingle or detached clay. Do not dig into cliffs, in-situ beds or ledges. Use hand tools sparingly and leave promising ammonite nodules intact for specialist assessment.
CLEANING AND TREATING
Begin with gentle dry brushing of loose sediment, stopping if the fossil or matrix crumbles. Do not apply a fixed soaking treatment to every specimen: pyritic ammonites and friable mudstone need assessment before any wet cleaning. Water cleaning is appropriate only where the material is sound and water-safe. Let wet finds dry gradually at room temperature, away from radiators and other heat sources.
Sound specimens do not need routine coating. Where a fragile fossil needs consolidation, seek advice on selective consolidation with Paraloid B-72. It is soluble in suitable solvents, but complete removal from porous fossils or matrix cannot be guaranteed. A consolidant is not a cure for active pyrite decay, and treatment should preserve diagnostic surfaces and any useful adhering matrix.
Avoid decorative varnish on ammonites: a glossy coating can obscure surface detail and complicate later preparation. Leave potentially important specimens uncoated and seek specialist advice before cleaning or treating them.
Pyritic Fossils
Pyritic fossils require special care. While there are methods to slow down pyrite decay (pyrite rot), there is currently no permanent way to completely prevent it. Commercial treatments such as Pyrite Stop can be effective, but they are time-consuming and require careful application. An alternative approach is to store pyritic specimens in sealed containers with silica gel sachets, which help remove moisture from the air and slow deterioration.
Pyritic ammonites and fossils enclosed in hard nodules may need specialist preparation. Abrasive cleaning, wire brushing and washing are not a standard treatment for every specimen. Keep dry pyritic material in a stable, low-humidity enclosure and inspect it regularly; isolate specimens developing powder, cracking or other signs of decay and seek conservation advice. Do not seal damp fossils in a box.
IDENTIFY YOUR FINDS
Need help identifying a fossil? Share clear photos, where you found it and its size with the community.
FURTHER READING
Deposits Magazine – Book review: A Guide to Fossil Collecting on the West Dorset Coast
Deposits Magazine – Interpreting ammonite fossils
Golden Cap and Seatown – Ian West’s geological field guide
Rare Jurassic ‘Sword Dragon’ prehistoric reptile discovered in the UK
The Fossil Collecting Code – Charmouth Heritage Coast Centre
ACCESS RIGHTS
This site is an SSSI and forms part of the UNESCO World Heritage Jurassic Coast. Follow the West Dorset Fossil Collecting Code and local landowner restrictions. Search loose beach material responsibly, leave rock ledges intact, and do not dig into cliffs or climb landslips. Important or unusual finds should be recorded and referred to the Charmouth Heritage Coast Centre for advice. For full information about the reasons for the status of the site and restrictions please download the PDF from Natural England – SSSI Information – West Dorset
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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