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.
♦ 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. There is a small car park, run by the Anchor Inn, at Seatown, which is highly recommended, as parking elsewhere is very limited.
♦ Parking along the roadside at the bottom is possible between the 1st October and the 24th May. The double yellow line parking restrictions only apply in peak season.
♦ 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
DOWNLOAD THE UKF BOOKLET TO FOSSIL HUNTING AT SEATOWN
PROFILE INFO
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 need to be professional prepped with Iron abrasives.
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. In addition, there is a hard layer at about eye-level at the lower part of the cliff at Golden Cap, where ammonites can be found and, of course, fossils can also be found in the slippages. This is also an excellent location for microfossils. These can be found by taking samples from the clay surrounding pockets of crinoids and belemnites in the Belemnite Stone Beds during scouring conditions
VIDEO FILM
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. is not fossiliferous. These beds are the Green Ammonite Member, which contains limestone bands and scattered nodules. The latter may contain ammonites. Often, lumps can be found near the base of the cliff and these can be split open, to be explored for nodules or loose fossils. Ammonites preserved in the mudstone will, invariably, be crushed or missing the centre. This is caused by a lack of sediment in the entire shell during the early stages of fossilisation.
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. Typically, these will be keels of the ammonite, Androgynoceras, as shown below.
When you finally reach Golden Cap, at the first slippage, you will notice that there is a lot of soft mudstone. The rock is susceptible to rapid erosion and the sea washes this out daily, so fresh fossils are often be found here. Look in the clay, the slippages and the foreshore. Most of the fossils (particularly ammonites) are washed out and can simply be picked up, often requiring no preparation.
Continuing around the first slippage past the peak of Golden Cap (and staying away from the sheer cliff face, as it often crumbles), you should search the 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.
During the winter months, the Belemnite Stone is exposed, which is full of crinoids, belemnites, ammonites and microfossils. 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.
The microfossil assemblage at Seatown is varied and typically includes foraminifera such as Lenticulina, Marginulina, Planularia, and Dentalina, along with abundant ostracods, small bivalves, gastropods, echinoderm ossicles, crinoid fragments, and fish remains including scales and teeth. When conditions are favourable, micro-ammonite fragments and juvenile belemnite guards may also be recovered. Together, these microfossils provide valuable insight into the Jurassic marine environments of the Dorset coast and reward careful, patient collecting.
GEOLOGY
Golden Cap is the highest point on the south coast of England and presents one of the most impressive cliff sections in Dorset, exposing a long sequence of Upper Jurassic to Lower Cretaceous rocks. The cliffs record a major transition from Jurassic marine environments into the later Cretaceous seas and coastal systems.
Capping the cliff is the Upper Greensand Formation, which is visible for miles along the coast. Its distinctive warm yellow-gold colour, especially striking in low evening sunlight, gives Golden Cap its name. Together with the underlying Gault Clay, these formations form the uppermost 60 metres of the cliff and are Cretaceous in age. The Upper Greensand represents deposition in shallow marine conditions, while the Gault Clay below reflects a deeper, quieter marine environment with fine sediment settling out of suspension.
Beneath the Gault Clay, the succession steps back into the Upper Jurassic, beginning with approximately 22 metres of Down Cliff Sand. This unit marks a significant change in sedimentation, representing more energetic marine conditions with sandy deposits laid down on the sea floor. At the base of the Down Cliff Sand lies the well-known Starfish Bed, a thin but important horizon from which fossil starfish can very occasionally be recovered. These delicate fossils are rare at Golden Cap itself, but are more commonly found at Thorncombe Beacon, where the equivalent beds lie lower in the cliff and are slightly thicker, increasing the chances of preservation and exposure.
Below the Down Cliff Sand lies the Eype Clay, a substantial unit forming around 45 metres of the cliff. This clay-rich formation represents quieter marine conditions and is notable for containing the Eype Nodule Bed, a horizon of cemented nodules which can preserve fossils in exceptional detail. The Eype Clay is an important marker within the local stratigraphy and often contributes to landslips due to its unstable nature when waterlogged.
Underlying the Eype Clay are the Three Tiers, a sequence of interbedded limestones and marls that form a stepped profile in the cliff face. Beneath these, the Green Ammonite Member makes up the remaining 34 metres of the exposed section. This member is particularly fossiliferous, yielding a range of ammonites, bivalves, and other marine fossils, and reflects a return to more oxygenated bottom waters.
On the lower foreshore, particularly during winter storms or strong scouring conditions, the Belemnite Marl Member can occasionally be exposed. This bed is highly fossiliferous and produces abundant, well-preserved belemnites, along with ammonites and a rich assemblage of microfossils. However, during the summer months this unit is typically buried beneath beach sand, making access to it sporadic and dependent on recent coastal erosion.
This is a detailed stratigraphic breakdown of the Black Ven succession at Charmouth, Dorset. The cliff exposes the upper Blue Lias, the Shales-with-Beef Member, the Black Ven Marl Member, the Stonebarrow Pyritic Member and the Belemnite Marl Member, all capped unconformably by Lower Cretaceous Gault and Upper Greensand strata.
LIAS GROUP
Blue Lias Formation (Uppermost Part Only)
Top Blue Lias
Grey Ledge
The highest persistent limestone of the Blue Lias at Black Ven. It forms the hard top of the Blue Lias bench and is capped by a prominent bioturbated erosion surface that marks the base of the overlying Shales-with-Beef Member. This is the last major limestone platform before the sedimentary regime changes into the dark mudstone-dominated Charmouth Mudstone succession above.
Charmouth Mudstone Formation (Lower Jurassic — Sinemurian to Pliensbachian)
Shales-with-Beef Member
The Shales-with-Beef Member forms the lowermost part of the Charmouth Mudstone Formation at Black Ven and is about 28–30 metres thick in the Lyme Regis–Charmouth area. It consists of thinly interbedded medium- to dark-grey mudstones, paler blocky calcareous mudstones and darker organic-rich laminated mudstones, with numerous bedding-parallel fibrous calcite seams or “beef”. The member contains several persistent limestones and concretion horizons that provide the real field framework for the Black Ven lower cliff.
Basal Erosion Surface And Lower Shales-With-Beef
The base of the member rests sharply on Grey Ledge along a prominent burrowed and bioturbated surface. The lowest beds are thinly interbedded grey mudstones and organic-rich mudstones, locally with crushed Arnioceras and early pyritisation, recording the start of the post-Blue Lias muddy shelf regime.
Fish Bed Shales And Fish Bed
The Fish Bed interval comprises lower fissile shales, then the Fish Bed itself as a strikingly laminated calcareous siltstone, followed by more dark shales and in places an “upper” Fish Bed siltstone. These beds are some of the most useful markers in the lower member and record episodic silt influx into otherwise muddy, organic-rich marine sedimentation. Fossils include fish debris, shell fragments and ammonites in adjacent shales.
Table Ledge
A pale, muddy limestone lens-bed with nests of iridescent rhynchonellid brachiopods. Table Ledge is one of the most important marker beds in the member and can be traced widely in the Black Ven–Charmouth area. It forms a resistant bench within the lower Shales-with-Beef succession and marks a brief interval of stronger cementation and clearer-water carbonate accumulation.
Beds Between Table Ledge And Devonshire Head Limestone
Mainly thinly interbedded medium and dark grey mudstones with organic-rich brownish-grey laminated mudstones and numerous thin seams of beef. This interval is one of the thickest parts of the member and records persistent low-energy, oxygen-poor marine deposition punctuated by early diagenetic calcite growth.
Devonshire Head Limestone
A laterally persistent limestone horizon in the middle part of the member. It is a very useful field marker west of Black Ven and below The Spittles, and the top of the bed locally carries phosphatic nodules, suggesting a break or condensed phase. It helps divide the lower and upper halves of the member.
Middle Shales-With-Beef
Dark grey mudstones, laminated brownish-grey bituminous mudstones and numerous thin seams of beef, with septarian concretions in places. This interval contains many of the classic fossil mudstones and contributes greatly to the instability of the lower Black Ven cliff.
Spittles Limestone
A tabular muddy limestone, passing locally into septaria coated with beef or into a thick multiple layer of beef. It is one of the most prominent resistant markers in the upper part of the member and is especially useful in the Spittles–Charmouth area.
Upper Shales-With-Beef And Birchi Nodules
Thinly interbedded grey mudstones and organic-rich mudstones with several thin beds of beef and one or two lines of septarian nodules. The Birchi Nodules are especially characteristic and may enclose Microderoceras birchi. These beds form the fossil-rich upper part of the member immediately beneath its top limestone.
Birchi Tabular Bed
An almost continuous dense muddy limestone, 0.15–0.30 m thick, capping the Shales-with-Beef Member. This is the upper boundary marker of the member throughout the outcrop and forms a strong reef or ledge on the foreshore where exposed.
Total Thickness Of Shales-with-Beef Member At Black Ven: Approximately 28–30 Metres
Black Ven Marl Member
The Black Ven Marl Member above the Birchi Tabular Bed consists of dark grey thinly interbedded mudstones and organic-rich mudstones with several important cementstone and nodule horizons. In the modern Dorset framework, the lower part up to the Coinstone is retained as Black Ven Marl Member sensu strictu, while the higher pyritic beds above the Coinstone are separated as the Stonebarrow Pyritic Member.
Bed 80 — Lower Cement Bed / Lower Cementstone
A conspicuous argillaceous carbonate horizon described by Lang and Spath as black conchoidal marl with several indurated bands. At Black Ven and east toward Charmouth it forms a key marker in the lower Black Ven Marls. It varies laterally from limestone to ferroan dolostone and preserves uncrushed ammonites more readily than the surrounding mudstones.
Bed 81 — Inter-Cement Mudstones
Dark fissile mudstones and paper shales between the Lower Cement Bed and the Pavior. These beds continue the organic-rich, pyrite-prone sedimentation of the lower member and yield pyritised ammonites and other fossils where freshly exposed.
Bed 82 — Pavior / Upper Cement Bed
A second important cementstone horizon above Bed 80. It forms a useful datum bed and, together with the Lower Cement Bed, brackets one of the main lower fossil intervals in the Black Ven Marls.
Bed 83 — Obtusus Shales / Stonebarrow Flatstones
Bituminous paper shales with the classic flatstone nodules. This is one of the most famous horizons in the Black Ven succession, notable for uncrushed ammonites such as Asteroceras obtusum, insects in nodules and, regionally, vertebrate remains. It forms a strongly recessive but palaeontologically important interval.
Beds 84–86 — Middle Black Ven Marls
Dark mudstones and shales with nodular limestone development in parts, forming the less easily subdivided middle of the member. These beds continue the ammonite-bearing, organic-rich marl deposition and have yielded pyritised fossils, marine reptiles and dinosaur material in the broader Black Ven–Charmouth area.
Bed 87 — Limestone With Brachiopods
A thin limestone marker bed with brachiopods and shell debris. This is one of the best marker bands high in the Black Ven Marl Member and helps place the upper part of the member on the cliff face.
Bed 88 — Upper Black Ven Pyritic Marls And Stellare Nodules
Dark pyritic marls and mudstones with the classic Stellare Nodules, which may contain beautifully preserved Asteroceras stellare. These beds are among the best known pyritised ammonite-producing levels in the Black Ven succession and represent increasingly condensed upper-Sinemurian deposition.
Bed 89 — Coinstone
An irregular bed of bored, encrusted and partly pyritised hiatus nodules forming the top of the Black Ven Marl Member sensu strictu. This bed marks a major non-sequence in the Dorset Lower Jurassic and is the key upper boundary of the classic Black Ven Marls.
Total Thickness Of Black Ven Marl Member sensu strictu (Beds 80–89): Approximately 27 Metres
Stonebarrow Pyritic Member
The Stonebarrow Pyritic Member comprises Lang’s beds 90–102 above the Coinstone. Although best observed east of Black Ven toward Stonebarrow, it is present at Black Ven and represents the pyrite-rich upper continuation of the traditional Black Ven Marls. These beds lack the large nodules typical of the lower Black Ven Marl Member, apart from isolated stone bands, and are dominated by dark pyritic mudstones with abundant ammonites.
Beds 90–94 — Lower Pyritic Marls
Dark pyritic mudstones and marls immediately above the Coinstone non-sequence. These beds yield abundant pyritised ammonites, especially Promicroceras, Echioceras and related forms, and represent the restart of sedimentation after the upper Black Ven hiatus.
Beds 95–98 — Middle Pyritic Marls, Including The Lymense Bed
Highly pyritic, locally beef-bearing mudstones and marls. The lymense Bed is a pyritic ammonite-rich horizon within this part of the succession and is one of the best fossil-producing levels of the upper pyritic sequence. Pyrite was formerly collected from this part of the Black Ven succession for sulphuric-acid manufacture.
Beds 99–101 — Upper Pyritic Marls
Dark pyritic marls continuing upward beneath the top stone horizons. Fossils are dominated by pyritised ammonites and associated marine invertebrates, with fewer large nodules than in the lower member.
Bed 102 — Watch Ammonite Stone
An isolated limestone horizon near the top of the pyritic member, known for ammonites of the Echioceras raricostatum type. It forms one of the few conspicuous harder bands in the upper pyritic sequence below the Belemnite Marl boundary.
Total Thickness Of Stonebarrow Pyritic Member: Approximately 16–17 Metres
Belemnite Marl Member
The Belemnite Marl Member forms the pale, higher Jurassic cliff at Black Ven and consists of alternating pale and dark grey calcareous marls and mudstones with abundant belemnites. Although the member is much better exposed eastward toward Stonebarrow and Golden Cap, it is present at Black Ven and is capped by the Cretaceous unconformity at the eastern end of the cliff. The full Lang et al. bed numbering runs from 103 to 121.
Bed 103 — Hummocky Limestone
The basal limestone of the Belemnite Marls, with irregular hummocky surfaces and nodular development. It marks the sharp base of the member above the pyritic Black Ven beds and is a condensed, fossil-rich horizon.
Bed 104 — Clays Above The Hummocky Limestone
Dark marls with small nodules resting directly above Bed 103. These form the darkest basal beds of the Belemnite Marls and lead up into the main lower limestone marker.
Bed 105 — Apoderoceras Limestone
A pale marly limestone forming the first strong limestone band in the member. It is associated with Apoderoceras leckenbyi and allied early Jamesoni-zone faunas and is one of the best lower Belemnite Marl markers.
Beds 106–109 — Lower Paler Marls And Gemmellaroceras Interval
A succession of pale marls and indurated pale bands with the characteristic lower pale–dark alternation of the Belemnite Marl Member. The interval includes the Phricodoceras indurated band and the Gemmellaroceras marls, and forms the first clearly striped part of the member above Bed 105.
Bed 110 — Lower Darker Marls
The great lower dark marl division of the Belemnite Marls, making up much of the lower half of the member. These bluish-grey marls yield abundant belemnites and form one of the thickest single bed groups in the entire member.
Beds 111–115 — Middle Pale And Dark Bands
A characteristic striped interval of alternating very pale indurated marls, softer pale marls and darker marl bands. These beds include the Lower Pale Band, Lower Dark Band, Middle Pale Band, Middle Dark Band and Upper Pale Band, and are among the most visually distinctive parts of the member in fresh cliff sections.
Beds 116–118 — Upper Dark And Pale Marls
Dark and pale marls forming the upper middle part of the Belemnite Marls, including faunal levels with Uptonia, Tropidoceras and Acanthopleuroceras. These beds continue the pale–dark rhythmic marl deposition but become increasingly fossiliferous toward the top.
Bed 119 — Belemnite Shales
Brown marly shales with impersistent crinoid limestone lenticles near the top. This is one of the classic upper Belemnite Marl divisions and leads into the highly fossiliferous pyritic beds below the Belemnite Stone.
Bed 120 — Pyritic Marls And Crumbly Bed
Pyritic marls with flattened sulphide nodules, capped by the crumbly belemnite-rich bed traditionally known as the old Belemnite Bed. This interval is highly fossiliferous and forms the rough-faced upper part of the member immediately below its top stone.
Bed 121 — Belemnite Stone
A persistent nodular limestone weathering creamy white. This is the top marker bed of the Belemnite Marl Member and the highest Jurassic bed clearly identifiable beneath the Cretaceous unconformity at the eastern end of Black Ven.
Total Thickness Of Belemnite Marl Member At Black Ven: Approximately 20–27 Metres, Though The Upper Part Is Locally Slipped And Truncated Beneath The Cretaceous Unconformity
Gault Formation (Lower Cretaceous)
Basal Cretaceous Unconformity
The Jurassic succession at Black Ven is cut by a marked erosional unconformity and overlain by dark grey Gault clay. At the eastern end of Black Ven, the Belemnite Stone and a limited thickness of weathered grey mudstone remain beneath this unconformity. The Green Ammonite Member is therefore not preserved here as a full cliff section.
Upper Greensand Formation (Lower Cretaceous)
Foxmould And Chert Beds
The cliff top above Black Ven is capped by Upper Greensand sands and cherts, which drive much of the modern landslip behaviour by feeding debris onto the Gault and Jurassic benches below. These Cretaceous units are not part of the Lower Jurassic fossil section but are an essential part of the Black Ven cliff profile.
Depositional Environment
The Black Ven succession records a long transition from carbonate-mud shelf deposition in the top Blue Lias, into organic-rich oxygen-poor mudstones with frequent early diagenetic calcite seams in the Shales-with-Beef Member, then into darker ammonite-rich marls and cementstones of the Black Ven Marl Member, followed by the pyrite-rich upper Sinemurian Stonebarrow Pyritic Member and the paler belemnite-rich marls of the lower Pliensbachian Belemnite Marl Member. The whole Jurassic section is finally cut by a major Early Cretaceous erosional surface.
Total Thickness Covered Here: Approximately 90–115 Metres Of Jurassic And Basal Cretaceous Stratigraphy Across The Main Black Ven Cliff Profile
References
Gallois, R.W. (2008). The lithostratigraphy of the Shales-with-Beef Member of the Charmouth Mudstone Formation, Lower Jurassic.
Lang, W.D. & Spath, L.F. (1926). The Black Marl of Black Ven and Stonebarrow, in the Lias of the Dorset coast.
Lang, W.D., Spath, L.F., Cox, L.R. & Muir-Wood, H.M. (1928). The Belemnite Marls of Charmouth, a series in the Lias of the Dorset coast.
British Geological Survey Lexicon: Shales-with-Beef Member, Black Ven Marl Member and Belemnite Marl Member.
British Lower Jurassic Stratigraphy (JNCC GCR volume) and west Dorset coastal field guides.
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.
Once you have passed the headland at Seatown, it is no longer possible to judge sea conditions back at the main beach. For this reason, collectors should always plan to return as soon as the tide turns.
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 professional preparation, ideally using iron oxide abrasive techniques.
For collecting on the beach, a geological pick and a small trowel are strongly recommended for careful extraction from shingle and clay. A geological hammer may occasionally be useful, but should be used sparingly and with care.
CLEANING AND TREATING
Begin by removing any loose sediment very carefully using a soft toothbrush. Take your time, as many fossils—particularly pyritic specimens—are fragile and easily damaged. Once cleaned, fossils should be desalinated by soaking them in fresh water for at least 24 hours to remove residual salt. After soaking, allow specimens to dry naturally at room temperature. Do not dry them on radiators or other heat sources, as rapid drying can cause cracking or long-term damage.
Once fully dry, we recommend sealing fossils with Paraloid B-72, dissolved in acetone. This is a museum-grade consolidant that is widely available in pre-mixed bottles. Paraloid B-72 is stable, long-lasting, and does not yellow or react chemically over time. Importantly, it is also fully reversible, making it suitable for scientifically important or display-quality specimens.
Some collectors prefer to treat ammonites with artists’ varnish. This is acceptable for common species that are not of scientific importance, as it enhances colour and contrast and can make a specimen really “pop”. However, varnish is not reversible and is therefore not recommended for rarer or research-grade fossils.
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.
For cleaning pyritic ammonites, our preferred method is to carefully blast them using iron oxide abrasive, followed by thorough washing and complete drying. The specimen is then lightly buffed with a brass brush to enhance surface detail. For pyritic material, varnish generally performs better than Paraloid, which can sometimes flake or react during active pyrite decay.
DISCUSSIONS
Seatown Find
Hi - struggled to find much over the last week in Dorset. is this just an interesting rock for the garden ?? 📷 📷
Lyme Regis (Seatown) fossils?
Can anyone please provide identifications of the attached? Are these even identifiable? Thanks so much. 📷
Seatown pyrite ammonite - Amaltheus or Harpoceras?
Hello, I found this in Seatown. It’s very small so may be a juvenile? The only thing I am confident of is it...
Seatown ammonites - ID confirmation on two and assistance needed on two
I thought I would try Seatown today, having previously stayed near Charmouth. Is the first one (first photo) Tragopylloceras loscombi? It doesn’t have...
Ammonite ID, Seatown, Dorset
Afternoon all, I’ve been trying to do a bit of basic prep on this ammonite, found at Seatown in Dorset recently. I thought...
Vertebra - Seatown beach
Hi, Please delete if not appropriate for this site, but you are a knowledgable bunch ! Picked up this morning at Seatown. Pretty...
Collections of Fossils found at the Valley of Rocks and Seatown.
Good afternoon, I was wondering if anyone can help. I did a bit of the tour of the west country this week, and...
Found at Seatown
Hi Everone, Can anyone identify this found at Seatown Dorset. Thanks 📷
Found at Seatown
Hi Everyone Any ideas what this is, found at Seatown Dorset. Thanks 📷
ARTICLES
ACCESS RIGHTS
This site is an SSSI and forms part of the UNESCO World Heritage Jurassic Coast. This means you can visit the site, but hammering the bedrock is not permitted. 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‘
LINKS
♦ Fossil Discussions
♦ Fossil Articles
♦ Buy Fossils, Tools and Equipment
♦ Buy Crystals, Meteorites, and Artefacts
♦ Join Fossil Hunts
♦ UK Fossils Network
