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.
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
PROFILE INFO
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.
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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.
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.
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.
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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