The northern rocks at Whitesands Bay expose steeply inclined Cambrian beds beside a broad sandy beach. Fossils are sparse, but careful observation of loose rock surfaces may reveal dark impressions of small brachiopod shells, giving a glimpse of the ancient sea in which these sediments formed.
FIND FREQUENCY: ♦ – Occasional brachiopods; identifiable finds are not guaranteed.
CHILDREN – The sandy beach offers family interest, but the uneven northern rocks and cliff margins need close supervision.
ACCESS – Beachside parking and a ramp to the sand; the fossiliferous rocks are uneven and tide-dependent.
TYPE – Northern rocky shore and loose blocks of the Cambrian Lingula Flags Formation.
DIRECTIONS
♦ Follow the B4583 from St Davids to Whitesands Bay.
♦ Use the signed beachside car park and check the current signs and charges. Toilets and a café serve the beach; availability and lifeguarding are seasonal.
♦ From the car park, descend to the beach. Facing the sea, turn right and walk north towards the rocky end of the main bay. This corrects the old ‘walk left’ instruction while retaining the original northern collecting locality.
♦ Stay within the main northern beach section rather than continuing around headlands into neighbouring coves. The beach ramp does not provide step-free access across the fossiliferous rocks, and its base can change after winter storms.
♦ Original locality reference: 51.89651°N, 5.29642°W.
FOSSIL HUNTING
The occasional fossils at the northern end of Whitesands are brachiopods in loose blocks derived from the Lingula Flags Formation. The original guide’s photographs show dark, flattened shell impressions, and Lingulella davisii is the characteristic species recorded by BGS from this formation. This is a useful formation-supported identification, but it is not evidence that every dark patch or every bed at the beach contains the species.
Begin with naturally exposed surfaces of already loose blocks in a safe area where inspection is permitted. Look for a small, coherent shell outline and any preserved surface detail rather than colour alone: dark mineral patches, stains and irregular fractures can resemble a fossil at first glance. Oblique light and a hand lens help reveal the boundary between an impression and its fine-grained matrix. Many blocks will show no recognisable fossils.
The rocks include siltstone as well as mudstone, so do not restrict attention to pieces that look like soft shale. The beds are steeply inclined and the material on the beach has weathered and broken away from them. A loose block’s position on the sand does not identify its precise original horizon. Record where it was found and whether it was loose, and photograph it with a scale before any permitted removal.
The fossil area is the northern part of the main Whitesands beach. Neighbouring Pwlluog or Porthlleuog has a different stratigraphic and fossil record; its Ordovician trilobites are not expected finds from the Lingula Flags blocks described here. Likewise, the name ‘Whitesands Bay Formation’ in newer Cambrian literature does not identify the rocks beneath every part of Whitesands Bay.
A promising impression does not justify breaking the whole block apart. The dark fossil film may be delicate, and uncontrolled splitting can destroy it. Retain matching halves if a piece has already separated naturally; keep in-situ examples undisturbed and use photographs to document them.
Significant discoveries, geological research and conservation milestones at Whitesands Bay.
1930 – Detailed geological description
Cox, Green, Jones and Pringle published their account of the St Davids district and an associated summer-meeting report. This work underpins the recognition of the northern Whitesands shore as a partial type section of the Lingula Flags Formation.
1974 – Cambrian correlation
Rushton’s regional Cambrian synthesis provided a broader framework for interpreting the Lingula Flags succession. This was a stratigraphic synthesis, not a dated first discovery of the beach’s brachiopods.
1992 – Geological mapping
The St Davids geological map identified the local formation pattern that underlies the present digital mapping of Lingula Flags at the northern collecting locality.
2014 – Revised wider Cambrian nomenclature
A revision of the district’s Cambrian succession introduced a separate Whitesands Bay Formation. The similarly named unit should not be confused with the Lingula Flags exposed at the northern fossil locality.
GEOLOGY
The northern rocky end of Whitesands Bay is a partial type section of the Lingula Flags Formation and is identified as that formation on current BGS mapping. Its alternating pale siliceous and feldspathic siltstones and green-grey to buff micaceous mudstones record deposition of fine sediment in an ancient sea. Brachiopod shells occur within the formation, sometimes locally abundantly, although the visitor’s loose blocks generally yield only occasional recognisable examples.
The BGS formation-scale age range spans the traditional St David’s–Merioneth divisions of the Cambrian; the Lingula Flags are often discussed in a late Cambrian context. This broad range does not assign every northern-beach block to one precise stage. It should not be combined with the old guide’s contradictory assignment to a ‘Menevian Group’ and a precise numerical age range. BGS records no formal parent group for this formation in the relevant Lexicon entry. The modern geological literature also contains a distinct, older Whitesands Bay Formation; its geographical name is not a reason to substitute it for the mapped Lingula Flags at the northern fossil locality.
Later deformation has tilted the beds steeply, and the original photographs show unconsolidated material resting above the bedrock. The beach is consequently a view across inclined layers, weathered surfaces and loose debris, not a horizontal sequence in which each step north necessarily reaches a younger bed. Neither a complete local thickness nor a bed-by-bed measured section has been established for this short collecting stretch.
At the wider regional scale, the Lingula Flags pass down into Menevian mudstones, while their upper boundary is often faulted and locally affected by erosion before early Ordovician deposition. A marked Cambrian–Ordovician break is important around the broader bay, but it must not be assigned indiscriminately to the photographed fossil blocks or turned into a route through a neighbouring cove. The chart therefore concentrates on the formation actually supported at the northern shore.
Explore the northern Whitesands Lingula Flags, their fossil evidence and the limits of the local stratigraphic record.
Exact locality. The northern rocks of the main Whitesands beach form a partial type section of the Lingula Flags Formation. The original locality coordinate also maps to that unit. The map is a 1:50,000 interpretation, not a surveyed bed contact or a collecting-permission boundary. From the beach entrance facing the sea, this is the right-hand, northern shore.
Lingula Flags Formation
Lithology and sedimentation. The BGS Lexicon describes interbedded pale siliceous and feldspathic siltstones and green-grey to buff micaceous mudstones. The map’s broader sandstone-and-mudstone classification expresses a different scale of description. Alternating fine marine sediments are supported; a precise water depth, storm-bed thickness or oxygen profile is not established for this short stretch.
Brachiopod-bearing beds. Lingulella davisii is recorded as locally abundant within the formation. The original northern-beach field account and fossil photographs support occasional dark brachiopod impressions in loose blocks here. They do not constitute a complete species survey of every bed, and fossil abundance elsewhere in the formation should not be promised on this beach. Diagnostic shell shape matters more than a dark colour alone.
Age and hierarchy. The full BGS Lexicon and mapped formation range spans the traditional St David’s–Merioneth divisions of the Cambrian. Although Lingula Flags is commonly discussed in a late Cambrian framework, this formation-scale range does not provide a precise stage assignment for every northern-beach block. The relevant BGS Lexicon entry gives no formal parent group; it is therefore not placed inside a Menevian Group in this guide. The older page’s numerical dates and mixed ‘Upper Cambrian/Merioneth/Menevian’ assignment are not retained as a precise modern correlation.
Lower and upper boundaries: regional context. BGS describes a conformable, gradational lower passage from Menevian mudstones. The upper boundary is generally faulted, with local evidence of angular unconformity below Arenig rocks. The regional account describes incised Cambrian relief at Whitesand Bay before early Ordovician deposition. These are wider stratigraphic relationships, not measured contacts assigned to the visitor’s northern loose blocks or a reason to extend the collecting route into another cove.
Structure, thickness and cover. Steep bedding is evident at the northern shore, with unconsolidated cover above bedrock in the original photographs. No exact dip is imported from a neighbouring measured point, and no named glacial log is inferred from the general cover. The formation’s regional thickness exceeding 600 m is not the thickness of this beach section. A complete measured northern-shore succession has not been recovered, so no bed numbers or thickness column are invented.
Names and neighbouring sites. The distinct Whitesands Bay Formation introduced in revised Cambrian stratigraphy is an older unit within the Porth-y-rhaw Group. A shared place name is not sufficient to replace the Lingula Flags identification of this northern locality. Ordovician trilobite records at Pwlluog/Porthlleuog, Ramsey Island assemblages and the Paradoxides fauna of Porth-y-rhaw are separate evidence and are not transferred into this guide’s expected finds.
Evidence limits and references. The BGS Lingula Flags Lexicon entry, northern partial-type designation and exact map result underpin this account, with BGS regional geology of Wales for wider boundary context. Cox, Green, Jones and Pringle (1930), the St Davids district geology and summer-meeting accounts, and Rushton’s 1974 synthesis remain important foundational references. The complete original texts of those works and the full Rees and colleagues (2014) chapter were not available for bed-level reconstruction here; chapter contents and abstracts have not been treated as measured logs.
SAFETY
Check tide times, swell and weather before visiting the rocks, and leave a clear route back along the main beach. Incoming water and surf can cut off the ends of the bay; do not round headlands on a rising tide.
Wet and algae-covered rocks are slippery, and loose material, cliff bases and overhangs should be avoided. Supervise children closely at the rocky shore. Seasonal lifeguarding of the beach does not establish safe access to geological exposures.
EQUIPMENT
Bring footwear with a good grip, a hand lens, camera, scale and tide information. For authorised collection, soft wrapping and a rigid box protect thin pieces. Natural surfaces can be inspected without a hammer; do not hammer the bedrock or disturb the cliffs.
CLEANING AND TREATING
Keep preparation minimal. Brush away only loose dry dirt with a soft brush, without scraping the dark fossil surface. Avoid soaking friable rock, acid treatment, varnish and aggressive mechanical work.
Wrap thin pieces individually, keep counterparts together and label the northern-beach find spot, date and loose-block status. Seek specialist advice for a fragile or potentially important specimen before applying consolidants or attempting to expose more of it.
IDENTIFY YOUR FINDS
Need help identifying a fossil? Share clear photos, where you found it and its size with the community.
FURTHER READING
BGS Lexicon: Lingula Flags Formation and the northern Whitesands partial type section
BGS regional geology of Wales: wider geological context
Visit Pembrokeshire: Whitesands beach access and facilities
ACCESS RIGHTS
Follow current conservation notices and ask the landowner before collecting. Do not hammer the bedrock or disturb the cliffs. The original guide identifies conservation interest here, but beach access and visitor facilities should not be interpreted as permission to remove fossils.
Use signed parking and paths and check current charges and seasonal arrangements. This guide covers the main bay’s northern rocks, not an extension into neighbouring coves.
It is important to follow our ‘Code of Conduct’ when collecting fossils or visiting any site. Please also read our ‘Terms and Conditions‘
Joe Shimmin. Last inspected 2007, Updated 2017, Edited by Jon Trevelyan 2016
LINKS
♦ Fossil Discussions
♦ Fossil Articles
♦ Buy Fossils, Tools and Equipment
♦ Buy Crystals, Meteorites, and Artefacts
♦ Join Fossil Hunts
♦ UK Fossils Network
