Burnham-on-Crouch (Butts Cliff)
Region: Essex
Nearest Town: Burnham-on-Crouch
Geological Age: Ypresian • Eocene • Palaeogene • Cenozoic
Site Type: Foreshore • Cliff • River
About the Site
Burnham on Crouch is an important London Clay fossil locality on the north bank of the River Crouch in Essex. The LBPS locality centres on the small river cliff traditionally known as The Cliff or Butts Cliff, between Creeksea and Althorne, together with the fossil-bearing foreshore immediately below it.
The exposed cliff is only around 2–3 metres high, but it has produced an exceptionally diverse Early Eocene fossil assemblage since becoming well known to collectors in the 1970s. The site is particularly noted for shark and ray remains, small fish fossils, crustaceans and rare bird bones.
Most fossils are small and are found loose amongst shingle and weathered clay rather than by excavating the cliff. Careful searching is therefore much more productive than simply looking for large obvious specimens.
The site is scientifically important enough to be protected as a geological SSSI and is also recognised through the Geological Conservation Review for both its fossil fish and fossil birds.
Site Images
Geology & Stratigraphy
The fossil-bearing sediments belong to the London Clay Formation, part of the Thames Group and of Ypresian age.
The London Clay here consists predominantly of marine silty clay and clayey silt. Large cementstone concretions weather from the low cliff and occur across the foreshore, although most of these nodules are not fossil-bearing.
Detailed studies place the exposed section within the traditional Division D of the London Clay, probably towards its upper part. Geological Conservation Review work correlates the section with a level approximately 26 metres below the base of the overlying Claygate succession.
In the modern BGS lithostratigraphic framework, Division D falls within the Sheppey Member of the London Clay Formation. The Sheppey Member is a widespread unit rather than something confined to the Isle of Sheppey despite its name.
Older specialist literature may also refer to the Burnham section as palaeontological Unit P13. This is a detailed correlation level used in regional work and is useful when comparing scientific records, but it is not a formal modern Geological Unit.
The historic term Division D remains useful when reading older fossil literature because many Burnham specimens and species descriptions were recorded using that subdivision.
Palaeoenvironment & Palaeoecology
The London Clay at Burnham was deposited in a warm marine shelf environment during the Early Eocene.
Fine clay and silt settled through relatively quiet marine water onto the seabed. In modern BGS interpretation, the Sheppey Member records conditions ranging across the marine shelf as water depth and sediment supply changed through the London Clay succession.
The Burnham fossil assemblage is strongly marine. Sharks and other cartilaginous fish are especially well represented, together with bony fish, crustaceans, molluscs and other marine organisms.
Terrestrial material also entered the sea. Fossil plant material and rare bird remains show that the marine environment received material transported from nearby land.
The ancient setting therefore bore little resemblance to the modern River Crouch. The present estuary has simply cut into marine sediments deposited roughly 50 million years earlier.
Fossil Preservation & Taphonomy
Burnham differs noticeably from some other London Clay localities in the way its vertebrate fossils are preserved and collected.
Fish remains commonly occur free within the clay matrix rather than enclosed inside large concretions. Teeth, small bones and other resistant remains can therefore be released as the clay is eroded and become concentrated amongst the fine shingle and beach sediment.
This has made bulk sampling and careful examination of small sediment particularly effective in scientific work at Burnham.
Large cementstone concretions are conspicuous on the foreshore, but unlike the fossil-bearing nodules familiar from parts of Sheppey, most Burnham cementstones are relatively unfossiliferous. Breaking every concretion is therefore neither productive nor appropriate.
Small vertebrate fossils can be very well preserved despite their size. Shark teeth are particularly characteristic, while rare bird bones demonstrate that small and delicate terrestrial material occasionally reached the marine depositional environment and survived burial.
Pyritised wood and other plant material may also occur.
Once fossils have weathered onto the modern foreshore they may be moved by tides and mixed with younger river deposits. A loose fossil should therefore not automatically be regarded as having come from the exact patch of clay beneath the place where it was collected.
Collecting Guidance
Visit around low tide, when the greatest area of fossil-bearing foreshore is exposed.
Careful searching of patches of fine shingle and naturally weathered London Clay is generally the most effective method.
Tidal scouring can remove surface mud and expose new concentrations of small fossils, although conditions vary considerably between visits.
Much of the material is tiny. Searching slowly on hands and knees can be much more productive than walking quickly along the shore.
Avoid sections covered by deep mud or thick seaweed even if they appear potentially fossiliferous.
Wear sturdy waterproof footwear with good grip.
Useful equipment includes:
- gloves
- knee pads
- a hand lens
- small specimen boxes or bags
- a fine hand sieve
- labels or a notebook
- a phone for tide and weather information
- drinking water for the walk
Gloves are particularly useful because broken glass and other river debris may occur amongst the shingle.
A geological hammer is not required for normal collecting and should not be used on the protected bedrock.
What to Look For
The most effective collecting involves getting close to the ground and searching small patches of shingle and washed clay very carefully.
Shark teeth are one of the characteristic finds. Many are small, so look for a definite enamel crown, cutting edges and a recognisable root rather than simply searching for large triangular teeth.
Tiny ray teeth and other fish remains can be much less obvious. Small vertebrae, bones and other fragments may only become noticeable when the fine beach material is examined closely or sieved.
Crustacean remains can occur as isolated pieces of carapace or claw.
Pieces of pyritised or mineralised wood may occur amongst the beach material. Look for recognisable grain or other organic structure rather than relying on colour alone.
Large cementstone nodules are common but are usually not worth breaking simply because they are present.
Transparent selenite crystals can also weather from the London Clay. These are minerals rather than fossils but are characteristic finds at the locality.
Unusual small bones deserve particular care because Burnham has produced scientifically significant fossil birds.
Use Fossils at this Site for identification of individual species.
Fossils at this Site
Explore fossils recorded from this site, see how to recognise them and, where enough LBPS records exist, what collectors are actually finding.
What collectors are finding
Typical examples from this site
Different anatomical parts or preservation styles can look very different. Choose an example to view it larger.
About this information
Fossil occurrences come from reviewed LBPS records. Encounter frequency and abundance use eligible collecting sessions where all finds were recorded. Preservation rarity uses the condition recorded at the time of collecting. Identification photographs may come from dedicated Fossil Examples or linked public LBPS Specimens; neither influences rarity or frequency calculations.
Visitor & Access Information
General Location
On the north bank of the River Crouch in Essex, west of Burnham-on-Crouch and close to Creeksea and Althorne.
The LBPS locality refers specifically to The Cliff / Butts Cliff and its associated foreshore, rather than the whole Burnham-on-Crouch river frontage.
Directions
A reliable approach is from Burnham-on-Crouch, walking west along the riverside and King Charles III England Coast Path towards Creeksea and Althorne.
Continue beyond the developed waterfront towards Creeksea and follow the established riverside route.
The fossil locality occurs farther west where the low London Clay cliff reaches the River Crouch.
This is a significant walk from central Burnham, so allow enough time for both the outward and return journey.
Older collecting guides describe foreshore crossings around slipways at Creeksea. Because the river is tidal and access arrangements can change, follow the current signed coast-path route rather than relying solely on historic directions.
Parking
The simplest option is to use established public parking in Burnham-on-Crouch and approach the locality on foot.
Maldon District Council currently provides free public parking in Burnham, including the Riverside car park, as well as Foundry Lane and Millfields.
Riverside is particularly useful for access towards the western riverfront.
Parking closer to Creeksea is very limited and restrictions have changed historically, so visitors should not assume roadside parking will be available there.
Terrain
The walk to the locality is principally along riverside and coastal paths.
At the fossil site itself, the foreshore consists of clay, mud, fine shingle, larger concretions and river debris.
The lower foreshore can be extremely muddy.
Wet London Clay becomes slippery, while the small shingle in which fossils are searched may contain broken glass and other modern debris.
The low cliff is actively eroding and should be viewed and searched from the foreshore rather than climbed.
Access, Permissions & Responsible Collecting
The locality is reached on foot along the north side of the River Crouch.
The King Charles III England Coast Path through this area is now open to the public, providing formal pedestrian access along the estuary.
Collecting should concentrate on small fossils and naturally released material lying loose on the foreshore.
Do not dig into or hammer the protected London Clay cliff. The natural erosion of the exposure continually releases material without the need for excavation.
The coastal-access right allows people to visit the foreshore but does not itself confer a right to remove fossils. Follow any landowner or site restrictions applying at the time of your visit and keep any collecting low impact.
Avoid damaging saltmarsh vegetation and minimise disturbance to birds using the Crouch Estuary.
Safety & Legal Information
Safety Information
The principal hazards are soft mud, tides, slippery clay and sharp river debris.
Avoid the lower muddy foreshore. People can become deeply stuck in soft estuarine mud, and apparently firm surfaces can deteriorate rapidly towards the river.
Check tide times before visiting.
Wet London Clay is extremely slippery, particularly around the base of the low cliff and on recently exposed surfaces.
Broken bottles, glass, metal and other river debris may occur amongst the beach material. This is particularly important because fossil searching often involves kneeling or placing hands directly amongst the shingle.
Do not climb or undermine the low cliff.
The locality involves a substantial walk from reliable parking, so allow adequate time, carry water and ensure you can comfortably complete the return journey.
SSSI / Legal Restrictions
The Cliff, Burnham-on-Crouch is a geological Site of Special Scientific Interest, designated for its important Early Eocene fossil fish and bird assemblages.
The geological SSSI lies within the wider protected Crouch and Roach Estuary, which is also internationally important for its estuarine habitats and birds.
Natural England’s coastal-access assessment specifically notes that the new public access rights allow people to reach the foreshore but do not themselves create a right to collect fossils.
Public access should therefore not be interpreted as unrestricted collecting permission.
Do not excavate or hammer the protected cliff. Any collecting should be restricted to small amounts of naturally released loose material where this is permitted by the relevant landowner or site rules.
Substantial fossil extraction, bulk excavation or scientific sampling may require landowner permission and Natural England consent.
Avoid disturbance to estuarine wildlife and observe any temporary access restrictions.