St Audries bay is another location along the Somerset Jurassic coastline providing more wave-cut platforms and cliffs in which to find ammonites, reptiles and shells from the Blue Lias. The location is less productive than adjacent locations, but is much quieter with fewer collectors.
DIRECTIONS
♦ Access is by parking at the Pay and Display car park at St Audries Bay.
♦ From here follow the coastal path East where you will find steps to the beach.
♦ If visiting Doniford, you can walk along the beach, and even return via the coastal footpath, but please note between Doniford and St Audries Bay, is a water crossing called ‘The Swill’, after heavy rain and during winter the water can be fast flowing and deep.
♦ Postcode to the Car Park: TA4 4DP; Google Maps
♦ What3Words to best area: ///sweetly.clearcut.dinner
PROFILE INFO
FIND FREQUENCY: ♦♦♦ – On the foreshore, St Audries Bay can be very productive and the best time to collect is during scouring conditions. Since this location has no nearby parking, the long walk means it has fewer collectors than other nearby locations.
CHILDREN: ♦♦♦♦ – This location is suitable for families
ACCESS: ♦♦♦ – A car park at St Audries Bay takes you directly onto the beach and it is easy to find.
TYPE: – St Audries Bay is a foreshore and cliff location, and fossils can be found in both. However, the vast majority of fossils are found in rocks on the foreshore or exposed during scouring tides.
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FOSSIL HUNTING
Fossil collecting at St Audries Bay is mainly carried out on the foreshore, where the Lower Jurassic rocks are exposed across a wide wave-cut platform. Conditions here can vary greatly. At times the beach may be covered by sand or shingle, making collecting difficult, while after strong tides or winter storms the foreshore can be well scoured, exposing fresh rock surfaces and newly fallen material. When this happens the site can be very productive.
From the beach steps, walk westwards towards the headland where the Lower Jurassic Lias rocks are exposed. Most fossils are found on the wave-cut platform, amongst fallen blocks, or within scree slopes at the base of the cliffs. Fossils are sometimes also seen weathering directly from the cliff face, although extreme caution should always be taken when approaching the cliffs due to the risk of rockfalls. A hard hat is strongly recommended when working close to the cliff base.
Ammonites are the most common fossils at St Audries Bay and occur in several distinct layers within the Lower Lias. One of the most easily recognised horizons occurs approximately one metre above a prominent oyster bed, which forms a hard limestone platform on the foreshore near the Doniford headland. This layer often contains ammonites that have weathered free from the rock. Early Jurassic species such as Psiloceras planorbis, Psiloceras tilmanni and Caloceras johnstoni can be found here, representing some of the earliest ammonites of the Jurassic seas.
Further west along the foreshore additional ammonite-bearing beds occur. These may yield species such as Waehneroceras portlocki, Laqueoceras sublaqueus, Alsatites laqueus and Alsatites liasicus, which are often preserved as flattened impressions within the limestone or shale. Other ammonites that may occasionally be found in the Lias beds at St Audries Bay include Schlotheimia angulata, Schlotheimia complanata, Arnioceras semicostatum, Asteroceras obtusum and Oxynoticeras oxynotum. Many of these occur in higher beds and are most commonly discovered in fallen blocks or amongst boulders on the beach.
In addition to ammonites, a range of other marine fossils may also be encountered. Large oyster beds composed of Gryphaea arcuata are common in some layers and form distinctive fossil accumulations within the limestone. Other bivalves such as Cardinia listeri, Pecten and Plagiostoma may also be present. Brachiopods including Lobothyris punctata and Calcirhynchia calcaria occasionally occur within the limestones, while fragments of crinoids can sometimes be found scattered across bedding planes. Belemnites such as Passaloteuthis and Acrocoelites may also appear within some of the beds, although they are less common than ammonites at this location.
Many of the best specimens are found after recent cliff falls, when fresh blocks of fossil-rich limestone are exposed on the beach. After storms it is not unusual to find large ammonites weathered out of these fallen rocks lying loose on the foreshore. Because the cliffs here are continually eroding, new material is constantly being released, meaning that patient searching of the beach and boulder fields can often reward the careful collector.
GEOLOGY
St Audries Bay displays one of the most complete and varied geological sections on the Somerset coast. The bay exposes rocks ranging from the Upper Triassic Mercia Mudstone Group through the Penarth Group and into the Lower Jurassic Blue Lias Formation, illustrating the major environmental changes that occurred at the end of the Triassic and the beginning of the Jurassic.
To the east of the bay the cliffs expose the distinctive red and brown mudstones of the Mercia Mudstone Group, deposited during the late Triassic in arid continental environments dominated by mudflats, lagoons and ephemeral lakes. These sediments were laid down in a largely desert-like climate before the sea flooded the region at the end of the Triassic. The headland known as Blue Ben clearly shows where these Triassic rocks are faulted against the younger Jurassic beds, creating a striking contrast between the red marls of the Mercia Mudstone and the darker grey marine sediments of the Jurassic.
Above the Mercia Mudstone Group lie the transitional marine sediments of the Penarth Group, which record the initial flooding of the area as sea levels rose during the Rhaetian Stage of the latest Triassic. These rocks represent the gradual shift from continental to marine conditions as the sea spread across southern Britain.
To the west of the bay the cliffs and foreshore are dominated by the Blue Lias Formation of the Lower Jurassic. These rocks consist of alternating bands of dark grey or black shale and pale limestone that form the distinctive stepped cliffs seen along much of the Somerset coast. The Blue Lias was deposited in a shallow marine sea around 200 million years ago, shortly after the start of the Jurassic period. The alternating layers reflect periodic changes in sedimentation and water chemistry, producing cycles of mudstone and limestone deposition.
Within the Blue Lias at St Audries Bay the Aldergrove Beds are particularly well exposed. These beds consist of alternating grey mudstones and limestones that form a broad wave-cut platform across the foreshore when conditions allow. Continued erosion by the sea regularly exposes fresh rock surfaces, revealing the bedding planes and fossil-bearing layers within the formation.
Moving further west along the coast reveals progressively lower parts of the Blue Lias sequence. The cliffs and foreshore here provide excellent exposures of the early Jurassic marine sediments, showing the repeating limestone and shale cycles that characterise this formation. These rocks record the establishment of stable marine conditions following the Triassic–Jurassic transition and form an important part of the geological story of the Somerset coastline.
SAFETY
Common sense when collecting at all locations should be used and knowledge of tide times is essential. You can easily be cut off by the tide as the sea always reaches parts of the cliff. Be careful of falling rocks, as the cliffs are quite high and regularly fall.
EQUIPMENT
Equipment for fossil collecting at St Audries Bay is fairly simple, but a few tools can make searching more productive. A geological hammer and splitting chisel are useful for opening loose rocks and nodules on the foreshore, particularly limestone blocks that may contain ammonites or shells. However, it is important to remember that St Audries Bay is part of a Site of Special Scientific Interest (SSSI), and hammering on in situ bedrock or the cliffs is not permitted. Collecting should therefore be limited to loose material that has naturally fallen onto the beach.
Many fossils can also be found simply by carefully searching the foreshore, especially after scouring tides when sand has been removed and the wave-cut platform is exposed. A good eye is often the most useful tool, as fossils frequently weather out onto bedding surfaces or lie amongst the boulders.
It is advisable to bring wrapping materials such as tissue, newspaper or bubble wrap to protect fragile finds, along with small containers for transporting specimens safely. Sturdy walking boots with good grip are recommended, as the foreshore can be uneven and slippery, particularly when wet or covered in algae. Safety goggles are also recommended when using hammers to split loose rocks.
CLEANING AND TREATING
Let the specimen dry out so it’s easy to clean with a brush. Begin by removing any loose sediment very carefully using a soft toothbrush. Do not dry them on radiators or other heat sources, as rapid drying can cause cracking or long-term damage. We also advise against using water on the fragile flat ammonites.
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.
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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