Rich in reptile remains, you can find bones at Lilstock loose along the foreshore. Lilstock also yields Jurassic ammonites, bivalves and fish remains. The Triassic Lilstock Formation contains fish, shark and reptile remains in blocks at the Eastern end of the bay as well as microfossils from the Sandstone.
FIND FREQUENCY: ♦♦♦ – This location is highly productive during winter storms for reptile remains, which are easily collected from the softer shale. Ammonites and shells can be found but are either crushed in the shale, or worn in the harder rocks and cobbles, so you are less likely to come away with any good specimens of these.
CHILDREN: ♦♦♦ – Although this location is suitable for families, the foreshore is very rocky and hard going. This makes it unsuitable for younger children, who will find climbing over the rocks and walking through the pebbles difficult.
ACCESS: ♦♦♦♦ – Access to the beach is fairly easy. You can park at the Lilstock car park and just walk down to the shore.
TYPE: This is a foreshore and cliff location, and fossils can be found in both. The vast majority are found in or at the base of the cliff after high tides, or exposed on the foreshore during scouring conditions. However, note that this site is an SSSI. Therefore, hammering the bedrock and cliffs is not permitted, but collecting loose material is.
DIRECTIONS
♦ Lilstock can be reached by using the A39 from Kilton.
♦ There is a car park at Lilstock. Park here and access the shore, where you can either walk east towards the Triassic Lilstock Formation or west for the Jurassic Blue Lias (which is recommended as a starting point).
cars.
♦ Postcode to Car Parking: TA5 1SU, Google Maps Link.
♦ What3Words: Lilstock Triassic Formation: ///hotspots.bleat.investors
♦ What3Words: Jurassic section: ///cuff.whistling.reefs
VIDEO FILM
FOSSIL HUNTING
Lilstock is one of the most important coastal fossil localities in Somerset because it exposes the transition from the latest Triassic into the earliest Jurassic. The wave-cut platform provides access to two very different fossil assemblages. To the west of the bay the rocks belong mainly to the earliest Jurassic Blue Lias, while to the east the foreshore exposes the famous Rhaetian bone beds of the Penarth Group. Together these beds record a major ecological change at the end of the Triassic and the beginning of the Jurassic seas.
The Blue Lias at Lilstock is best searched on the wave-cut platform and amongst fallen limestone slabs. The alternating layers of dark shale and pale limestone frequently split along bedding planes, revealing marine fossils. Ammonites are among the most recognisable finds and can occur within limestone beds or weathered free from the shale. Early Jurassic ammonites such as Psiloceras planorbis, Psiloceras tilmanni, Alsatites liasicus and Caloceras johnstoni may be encountered in these beds. Marine reptiles are also well known from this location, and Lilstock is particularly rich in reptile and fish remains. Fossils of marine reptiles such as Ichthyosaurus and Plesiosaurus have been discovered here, sometimes within the cliff itself or weathered out onto the foreshore after erosion. Fish remains are also present within the shales and limestone beds. Other marine fossils include bivalves such as Cardinia listeri and Modiolus hillanus, brachiopods including Calcirhynchia calcaria and Lobothyris punctata, and occasional crinoid fragments. Belemnites may also occur, although shells and invertebrates are generally less abundant here than at some other Jurassic sites along the Somerset coast.
To the east of Lilstock, the foreshore exposes the famous Rhaetian bone beds of the Penarth Group. These deposits formed during the final stage of the Triassic when rising sea levels flooded the region and created shallow marine conditions across the area. The bone beds are thin but extremely rich layers containing large numbers of vertebrate remains. Fossils are often concentrated within hard, dark layers that contain teeth, bone fragments, scales and coprolites. These accumulations represent material that collected on the sea floor and later became cemented within the sediment.
Most fossils from the Rhaetian beds are fish remains, many of which occur as small isolated teeth. Bony fish are particularly common and include genera such as Gyrolepis, Severnichthys acuminatus, Saurichthys, Birgeria, Lepidotesand Dapedium. These fishes occupied a range of ecological roles, from fast-swimming predators to shell-crushing forms adapted to feed on invertebrates. Shark remains are also present, including teeth and denticles from species such as Lissodus. The bone beds can also contain scales, bone fragments and coprolites, and occasionally small vertebrate remains from larger marine animals.
Reptile remains are much rarer but are of particular scientific importance. Teeth or bones from marine reptiles may occasionally be found amongst the debris, and the beds at Lilstock have produced evidence of large marine reptiles, including a fragment of the lower jaw from a giant ichthyosaur discovered in the uppermost beds. These discoveries highlight the rich marine ecosystem that existed here during the closing stages of the Triassic and the early Jurassic.
Collecting at Lilstock is often most productive after storms or heavy rainfall when fresh material has been washed out onto the foreshore. The bone beds frequently appear as thin, dark layers containing numerous fossil fragments, and careful searching of loose blocks can reveal fish teeth, scales and other vertebrate remains. Because many of the fossils are extremely small, patient searching of the rock surface can be rewarding. The combination of early Jurassic marine reptiles and the famous Triassic bone beds makes Lilstock one of the most significant fossil localities on the Somerset coast.
Some of the most significant fossil discoveries and scientific milestones from Lilstock include the formal naming of the Lilstock Formation, the discovery and description of the unusual ichthyosaur Excalibosaurus costini, the later discovery of a second specimen from the same area, and the giant Late Triassic ichthyosaur jaw described from the site.
1980 – the Lilstock Formation was formally introduced
The Lilstock Formation was formally introduced in modern British stratigraphy in 1980, with Lilstock giving its name to this important latest Triassic unit. This cemented the site’s importance not just for fossil collecting, but for the formal geology of the Triassic–Jurassic boundary beds in Britain.
1986 – Excalibosaurus costini described from Lilstock
Lilstock produced the holotype of Excalibosaurus costini, described by Christopher McGowan in 1986. This unusual Early Jurassic ichthyosaur is one of the locality’s best-known fossils and is famous for its elongated upper jaw, giving it a swordfish-like appearance.
1996 – second Excalibosaurus specimen collected from the same area
A second, much more complete specimen of Excalibosaurus was collected from the Lilstock area in 1996. This showed that the genus was better represented than first thought and provided much more information about its anatomy.
2003 – the second Excalibosaurus specimen was described
The more complete second specimen from Lilstock was described in 2003. This helped clarify the anatomy of Excalibosaurus and confirmed the distinctiveness of one of Lilstock’s most important marine reptile discoveries.
2018 – giant Late Triassic ichthyosaur jaw described from Lilstock
A giant lower jaw bone from the latest Triassic of Lilstock was described in 2018. The find showed that enormous ichthyosaurs, probably over 20 metres long, were still present right at the end of the Triassic and made Lilstock one of the key sites for the last giant ichthyosaurs.
2024 – new work on Rhaetian faunas reinforced the importance of the Lilstock section
Recent study of the Rhaetian succession at Lilstock has shown that its fish-dominated bone-bed faunas are unusual and may reflect deeper-water conditions than at many equivalent sites elsewhere in south-west England. This has added further importance to Lilstock as both a fossil and stratigraphic locality.
GEOLOGY
Lilstock Bay exposes one of the most important coastal sections across the Triassic–Jurassic boundary in Britain. The cliffs and foreshore show a succession running from the upper part of the Mercia Mudstone Group, through the Penarth Group, and into the earliest beds of the Lias Group. This sequence records the final stages of late Triassic sedimentation and the progressive marine flooding that led into the fully marine conditions of the earliest Jurassic.
At the base of the exposed succession is the Blue Anchor Formation, made up of pale green-grey mudstones and siltstones. These beds represent restricted late Triassic conditions, beginning in more evaporitic lagoonal or sabkha-like settings and passing upwards into increasingly shallow marine conditions. At Lilstock, the upper part of this formation includes the Williton Member, a distinctive local unit of fine sands, silts and shales unique to North Somerset and South Wales. The Williton Member is important because it records the earliest phase of the Rhaetian marine transgression in this western area, before marine conditions became more widespread further east.
Above the Williton Member lies the Westbury Formation, a sequence of dark grey to black laminated shales and mudstones with occasional limestones, sandstones and the well-known bone-bed horizons. These beds were deposited in a marine setting, but under relatively low-oxygen conditions for much of the time, which is why the shales are dark and organic-rich. The paper notes that, at Lilstock, the Westbury Formation appears to represent deeper-water conditions than at many equivalent Rhaetian localities farther east.
Overlying the Westbury Formation are pale, calcareous beds that at Lilstock are now better referred to as the White Lias Formation and Watchet Mudstone Formation. The White Lias consists of dense micritic limestones separated by calcareous mudstones and represents shallow, warm, restricted marine conditions with periodic pauses in sedimentation and occasional emergence. Above it, the thin Watchet Mudstone marks a change into slightly deeper, more poorly oxygenated marine conditions.
At the top of the exposed sequence is the Blue Lias Formation, which rests conformably above the Watchet Mudstone. These beds are characterised by alternating dark mudstones and pale argillaceous limestones, producing the familiar banded appearance seen in many lower Jurassic coastal cliffs. The lowest Blue Lias beds at Lilstock include the so-called pre-planorbis beds, deposited immediately before the first appearance of Psiloceras planorbis, the ammonite traditionally used to mark the base of the Jurassic. The Blue Lias records the establishment of more fully marine conditions at the beginning of the Jurassic, completing the long marine transgression that had begun during the latest Triassic.
This is a detailed stratigraphic breakdown of the classic Lilstock Bay section, west Somerset, where the upper Blue Anchor Formation, the full Penarth Group and the basal Blue Lias are exposed in cliff and foreshore. The locality is especially important because Lilstock is the type area of the Lilstock Formation and because the section shows the latest Triassic marine transgression, the attenuated White Lias–Watchet interval and the onset of Jurassic paper-shale sedimentation in a structurally disturbed basin-margin setting.
MERCIA MUDSTONE GROUP
Blue Anchor Formation (Uppermost Norian To Rhaetian)
Bed LS1 — Upper Blue Anchor Formation / Grey Marls And Williton-Equivalent Marine Beds
The low cliff and foreshore beneath the Penarth Group at Lilstock are formed by the upper part of the Blue Anchor Formation, the old Tea Green and Grey Marl interval. Lithologically these beds are pale green-grey dolomitic silty mudstones and siltstones with thin argillaceous and arenaceous laminae, together with a few hard pale cream to buff porcellanous mudstone and siltstone bands. In west Somerset the uppermost part becomes more varied and includes grey, black, green and rarely red-brown dolomitic mudstones, laminated siltstones, yellowish-grey dolostones, mudcracks, scarce halite pseudomorphs and locally gypsum, with bivalves and bioturbation in the higher beds. At Lilstock these upper marine-influenced beds are especially important because recent work has shown a Rhaetian vertebrate and bivalve fauna in the Williton-equivalent interval, including teeth or denticles of Lissodus, Gyrolepis, Sargodon and Saurichthys, indicating that marine influence had already reached the basin before deposition of the classic black Westbury shales. Environmentally this was a mudflat to lagoonal and sabkha-margin succession passing upward into increasingly marine conditions. The top of the formation is commonly burrowed and bored and is locally slightly unconformable beneath the Westbury Formation.
PENARTH GROUP
Westbury Formation (Rhaetian)
Bed LS2 — Basal Westbury Bone Bed And Erosional Surface
The base of the Westbury Formation at Lilstock is exposed only when storm-beach cover is low, but where visible it rests sharply on the Blue Anchor Formation across an irregular erosional or non-sequential surface. This basal transgressive lag may contain reworked Blue Anchor mudstone clasts, quartz grains, phosphatic pebbles and abundant vertebrate debris. It marks the onset of the main Rhaetian marine flooding of the west Somerset basin and is one of the key surfaces in the whole section.
Bed LS3 — Lower Westbury Black Shales And Bone-Rich Arenaceous Beds
Above the basal lag lie dark grey to nearly black mudstones and shales with thin limestones, sandstones and fossiliferous arenaceous units. The lower part includes the classic bone-rich Westbury horizons, with fish scales, teeth, spines and other phosphatised vertebrate debris. Thin-shelled marine bivalves such as Rhaetavicula contorta, Eotrapezium concentricum, Chlamys valoniensis and Tutcheria cloacina are characteristic of the formation. At Lilstock, recent taphonomic work suggests that the basal and higher bone beds are dominated by osteichthyan remains, with chondrichthyans much less abundant than at some shallower Rhaetian sites farther east, implying a somewhat deeper-water setting. Sedimentologically these beds record a rapid shift into a low-oxygen marine shelf or embayment in which fine black mud accumulated under dysaerobic to anoxic bottom conditions.
Bed LS4 — Upper Westbury Shelly Black Shales
The upper Westbury Formation continues as dark fossiliferous mudstones and shales with subordinate thin limestones and sandstones. Shell beds and additional bone-rich seams may occur within it, but the general lithological character is still that of black, marine, organic-rich mudstone. The upper contact passes into the overlying Cotham Member across a non-sequence rather than through a simple conformable bedding transition. At Lilstock Bay the Westbury is an essential but not always fully visible part of the section, because beach cover can obscure its base while the higher beds are more persistently exposed in the cliff.
Lilstock Formation (Rhaetian)
Cotham Member
Published Bed C1–C10 numbering is retained below because it is the established west Somerset bed-by-bed correlation used to trace the Cotham Member into Lilstock. The general lithological character of each bed is known from that coastal correlation, but the Lilstock-specific features most worth noting are the basal erosion surface, several levels of soft-sediment slumping, the much reduced ripple-sand interval in C5, and the burrowed hardground at the top of C10.
Bed C1 — Basal Lenticular-Bedded Mudstones, Slumps And Fish-Debris Lag
The base of the Cotham Member at Lilstock rests on an irregular erosion surface and lag rich in fish debris, sand grains and small black phosphatic pebbles. The bed itself is a greenish-grey calcareous mudstone and silty mudstone unit in which lenticular bedding, internal disruption and local soft-sediment slumping are conspicuous. At Lilstock these disturbed beds are particularly important because they pass laterally into more normal lenticular mudstones, showing that the deformation is primary and syndepositional rather than later tectonic crushing. The bed records abrupt shallowing and local instability on the sea floor after deposition of the black Westbury shales.
Bed C2 — Muddy Limestone Lens
C2 is a strongly cemented muddy limestone equivalent of the surrounding Cotham mudstones. It is lenticular rather than perfectly tabular and may itself be affected by local slumping. In the field it acts as one of the first useful marker bands above the base of the member, but it should not be mistaken for the White Lias; it remains wholly within the argillaceous Cotham facies.
Bed C3 — Thinly Bedded Greenish-Grey Mudstones With Silt Lenses
This bed is composed of weakly calcareous, greenish-grey laminated to thinly bedded mudstones with scattered silt lenses and isolated coarse-silt ripple structures. Fossils are sparse, in keeping with the generally impoverished west Somerset Cotham fauna. The bed records quiet-water deposition in a very shallow restricted lagoon or tidal-flat pond system, with intermittent traction transport of fine silt.
Bed C4 — Cemented Muddy Limestone
C4 is a harder, more strongly cemented muddy limestone developed within the same general lithofacies as C3. It may contain isolated ripple lenses and can be locally disturbed by the same syndepositional movement that affects nearby beds. Its value is mainly stratigraphic: it is one of the recurring limestone markers that allow the attenuated Cotham succession at Lilstock to be correlated with thicker west Somerset sections.
Bed C5 — Ripple-Laminated Sandstone And Calcarenite With Mudcracks
Elsewhere on the west Somerset coast C5 is a fine- to medium-grained sandstone or calcarenite with shell debris, wave-ripple lamination, mudstone partings and large desiccation cracks descending from its base. At Lilstock it is much reduced and is represented only by two, locally three, ripple laminae separated by mudstones. Even in this attenuated form it is a very important bed, because it records a short-lived higher-energy incursion across the restricted Cotham mudflat surface and shows that intermittent emergence and desiccation occurred during deposition of the member.
Bed C6 — Upper Cotham Greenish-Grey Calcareous Mudstones
C6 consists of thinly bedded to laminated, weakly calcareous greenish-grey mudstones with somewhat thicker more calcareous beds. It returns to the quieter, muddier style of Cotham sedimentation above the rippled C5 event bed. Depositional conditions were still very shallow and restricted, with repeated shifts between subaqueous settling and minor desiccation or reworking on a broad tidal-flat to lagoonal plain.
Bed C7 — Porcellanous Laminated Micritic Limestone
C7 is a thin-bedded, laminated, porcellanous micritic limestone that weathers into splintery slabs. Older authors linked this level with a Cotham Marble equivalent, and it is certainly one of the most distinctive carbonate marker beds in the member. At Lilstock, however, it is overlain by further mudstones of unmistakably Cotham lithology, so it should not be treated as the base of the Langport Member. It represents a brief interval of strong carbonate precipitation and early cementation within an otherwise muddy, restricted succession.
Bed C8 — Nodular And Lenticular Carbonate-Variable Beds
C8 is laterally very variable and may range from weakly cemented mudstone to muddy limestone or porcellanous limestone in alternating lenticular and nodular beds. At Lilstock this lateral instability is especially marked and contributes to the bed’s uneven weathering on the foreshore. The bed records rapidly fluctuating conditions of carbonate production, mud accumulation and early diagenetic cementation in a very shallow-water restricted setting.
Bed C9 — Upper Weakly Calcareous Mudstone
This is a relatively simple greenish-grey weakly calcareous mudstone bed forming the topmost muddy phase of the Cotham Member. Fossils remain few. Its main significance lies in separating the variable nodular-carbonate interval below from the hard burrowed marker limestone above.
Bed C10 — Burrowed Argillaceous Limestone Hardground
C10 is a highly bioturbated argillaceous limestone with abundant Thalassinoides and other burrow systems. Its upper surface is irregular, mineralised and locally carries encrusting oysters, making it one of the clearest omission surfaces in the whole Lilstock Bay section. This hardground is the key marker at the top of the Cotham Member and is immediately overlain by the porcellanous White Lias bed. In environmental terms it records a pause in sedimentation and firmground development on a shallow marine or marginal-marine floor.
Total Thickness Of The Cotham Member At Lilstock Bay: Roughly 1.5–2 Metres In The Modern West Somerset Correlation, But Locally Variable Because Of Erosion Surfaces And Soft-Sediment Deformation
Langport Member
Bed LS5 — White Lias / Lower Langport Porcellanous Limestone (c. 0.2–0.4 m)
At Lilstock Bay the limestone facies of the Langport Member is reduced to a single thin bed of dense, laminated porcellanous limestone, the local White Lias. It is pale grey to cream, very hard, micritic and laterally persistent, and may split into one or two leaves with a thin calcareous mudstone parting between them. This is a crucial marker bed because it is far thinner than the thicker White Lias limestones of mid-Somerset and south Devon, yet it preserves the same basic lithological identity. It represents renewed shallow-marine carbonate deposition after the restricted muddy Cotham phase, but under conditions of extreme condensation on the west Somerset basin margin.
Bed LS6 — Watchet-Type Upper Langport Calcareous Mudstones And Muddy Limestones
Above the porcellanous limestone lies a very thin but important mudstone-rich interval. In older Somerset usage this was termed the Watchet Beds or Watchet Mudstone facies; in current BGS nomenclature the Langport Member includes porcellanous limestone below and calcareous mudstone above, so this attenuated upper unit belongs within the Langport Member. At Lilstock it is only a few decimetres thick and may be as little as about 0.15 m in some exposures, but it changes laterally over a short distance into shelly calcareous mudstone, muddy limestone and local ripple-marked calcareous sandstone or siltstone. Crushed bivalves such as Liostrea, Modiolus and other shells may occur. The top is marked by a sharp change to the laminated organic-rich paper shales of the Blue Lias, recording an abrupt shift from an aerobic shelly sea floor to dysaerobic or anaerobic early Jurassic basin conditions.
Total Thickness Of The Langport Member At Lilstock Bay: Well Under 1 Metre, Including A Single 0.2–0.4 m White Lias Bed And Only Decimetres Of Overlying Watchet-Type Mudstone
LIAS GROUP
Blue Lias Formation (Latest Rhaetian To Lower Sinemurian Regionally; Only Basal Beds Exposed At Lilstock Bay)
The regional west Somerset Lower Lias bed numbering begins at the base of the fissile mudstone above the top of the Langport Member, but at Lilstock Bay only the lowest part of that succession is normally visible in the permanent cliff and foreshore. The two Blue Lias divisions used below are therefore practical site-use intervals for the Lilstock boundary section, not a replacement for the formal Whittaker & Green regional bed numbers used farther west in more complete Lower Lias sections.
Bed LS7 — Basal Paper Shales
The base of the Lias Group at Lilstock is marked by a sharp planar contact above the top of the Langport Member and the appearance of laminated brownish-grey organic-rich fissile mudstones, the classic paper shales. Fish scales are common, and the finely fissile texture records very low-energy mud accumulation under dysaerobic to anaerobic bottom-water conditions. This sharp lithological shift is one of the clearest formation boundaries in the whole section and represents the onset of the earliest Jurassic offshore mudstone regime.
Bed LS8 — Lowest Blue Lias Limestone–Mudstone Rhythms
Above the paper shales the first argillaceous limestone bands appear within grey calcareous mudstones and silty mudstones, beginning the familiar Blue Lias rhythm of limestone and mudstone couplets. On the wider west Somerset coast the first c. 5 m of the succession above the Langport Member are largely devoid of ammonites but contain a diverse bivalve fauna with abundant Liostrea hisingeri; only higher up do Psiloceras and the classic Planorbis-zone faunas become common. At Lilstock Bay itself the permanently visible section generally includes only the lowermost part of this interval, so it should be read as the base of the regional Lower Lias succession rather than as a complete Hettangian log.
Bed LS9 — Higher Hettangian To Lower Sinemurian Lower Lias In The Wider Lilstock Foreshore (Composite Context Interval)
Higher Lower Lias beds are present along the broader Blue Anchor–Watchet–Lilstock coast and in faulted foreshore blocks near Lilstock, but they do not form one simple, continuously measurable Lilstock Bay cliff section. Regionally they comprise a thick mudstone-dominated Blue Lias succession with subordinate limestones, passing upward into lower Sinemurian mudstones, and the broader coastal tract between Blue Anchor and Lilstock exposes 160–200 m of Lower Lias. Because faulting, repetition and local structural complexity become especially important toward Lilstock, it is more honest to treat those higher beds as part of the wider west Somerset composite Lower Jurassic succession rather than to force a fictitious continuous Lilstock-only log.
Stratigraphic Significance
Lilstock Bay is one of the key British reference localities for the latest Triassic and earliest Jurassic because it shows the upper Blue Anchor Formation, the full Penarth Group and the base of the Lias Group in one coastal section. It is also the type area of the Lilstock Formation, with its two constituent members, the Cotham and Langport. The section is especially valuable because the White Lias is so attenuated, the Watchet-type upper Langport mudstone is still present, and the basal Blue Lias paper shales lie directly above, allowing unusually clear study of the latest Rhaetian to earliest Jurassic transition.
Depositional Environment
The Lilstock succession records repeated environmental shifts across the end of the Triassic. The upper Blue Anchor Formation represents dolomitic mudflats, lagoons and sabkha-influenced marginal-marine settings with increasing marine influence upward. The Westbury Formation records full Rhaetian marine transgression into a relatively quiet, low-oxygen basin where black muds, shell beds and bone beds accumulated. The Cotham Member marks renewed shallowing into very restricted lagoonal, tidal-flat and intermittently emergent conditions with soft-sediment instability, ripple events and desiccation. The Langport Member represents renewed shallow marine carbonate deposition, but in highly condensed form on the west Somerset basin margin. The basal Blue Lias then records a return to more open offshore marine mud accumulation with organic-rich paper shales and the first regular Jurassic limestone–mudstone rhythms.
Structural Style And Exposure
Lilstock must be treated as a faulted and partly slumped composite foreshore locality, not as a single undisturbed measured cliff. Across the broader Blue Anchor–Lilstock coast both normal and reverse faults occur, and structural complexity is greater in the Lilstock area than farther west. Within the Cotham Member at Lilstock, slump structures occur at more than one level and pass laterally into undisturbed lenticular mudstones and siltstones, strongly suggesting syndepositional deformation, probably linked to basin-margin instability and perhaps seismic shocks. The modern foreshore is also a classic macrotidal washboard-like platform, so beach cover and tidal state strongly affect what can be examined on any visit.
Total Thickness Covered Here
The permanent Lilstock Bay boundary section includes many metres of upper Blue Anchor Formation, the exposed upper part of the Westbury Formation, roughly 1.5–2 m of Cotham Member, a very attenuated Langport Member with only a 0.2–0.4 m White Lias limestone plus a few decimetres of Watchet-type upper mudstone, and the basal paper-shale and limestone interval of the Blue Lias. Because the base of the Westbury is exposed only when storm-beach levels are low, and because foreshore structure and cover change along the bay, the locality is best understood as a detailed latest Triassic–earliest Jurassic composite section rather than as one single fixed measured cliff log.
References
Richardson, L. (1905, 1906, 1911) on the Rhaetic and White Lias succession of west Somerset, including Lilstock and St Audrie’s Bay.
Warrington, G., Audley-Charles, M.G., Elliott, R.E., Evans, W.B., Ivimey-Cook, H.C., Kent, P.E., Robinson, P.L., Shotton, F.W. & Taylor, F.M. (1980). A Correlation of the Triassic Rocks in the British Isles.
Hamilton, D. & Whittaker, A. (1977). Coastal exposures near Blue Anchor, Watchet and St Audrie’s Bay, north Somerset.
Whittaker, A. & Green, G.W. (1983). Geology of the Country around Weston-super-Mare.
Warrington, G. & Whittaker, A. (1984). The Blue Anchor Formation (late Triassic) in Somerset.
Mayall, M.J. (1981). The late Triassic Blue Anchor Formation and the initial Rhaetian transgression in south-west Britain.
Warrington, G. & Ivimey-Cook, H.C. (1995) on the Penarth Group and basal Lias of west Somerset.
Swift, A. (1995) on the White Lias / Langport Member facies variation in Britain.
Gallois, R.W. (2009). The lithostratigraphy of the Penarth Group (Late Triassic) of the Severn Estuary area, UK.
Durbin, L., Duffin, C.J., Hildebrandt, C. & Benton, M.J. (2024). Onset of the Rhaetian transgression in deep waters at Lilstock, north Somerset.
British Geological Survey Lexicon entries for Blue Anchor Formation, Westbury Formation, Lilstock Formation, Cotham Member, Langport Member and Blue Lias Formation.
JNCC / Geological Conservation Review accounts for the Blue Anchor–Watchet–Lilstock coast and the British Penarth Group sites.
SAFETY
Common sense when collecting at all locations should always be used and knowledge of tide times is essential. You can easily be cut off by the tide, as the sea always reaches some parts of the cliff. There are also regular cliff falls along this part of the coast, so keep well away from the base of the cliff. The beach is hard going with rocks and pebbles, which are not stable.
EQUIPMENT
Lilstock can be an unpredictable location for fossil collecting. At times the foreshore may yield very little, while after storms or favourable tides it can become extremely productive. Much depends on beach conditions and the amount of fresh material that has recently been washed out onto the wave-cut platform.
Most collecting is done by searching loose rocks and fallen boulders on the foreshore. A geological hammer and small chisel can be useful for splitting loose blocks that may contain fossils, and safety goggles are strongly recommended when breaking rocks. However, collectors must remember that Lilstock is designated as a Site of Special Scientific Interest (SSSI). As a result, hammering directly on the bedrock or cliffs is not permitted, and collecting should be restricted to loose material only.
Because many of the fossils from the Rhaetian bone beds are extremely small, it can also be helpful to bring small containers, sample bags or tissue to safely store delicate finds such as fish teeth and bone fragments. Sturdy footwear is essential, as the wave-cut platform can be uneven and slippery, especially when wet.
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.
ARTICLES
ACCESS RIGHTS
This site is an SSSI. 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
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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