Prestatyn Hillside combines an escarpment walk with glimpses of Carboniferous marine fossils. Occasional limestone blocks reveal crinoids, brachiopods and corals, while the surrounding rocks record sediment carried from a carbonate platform into deeper water.
FIND FREQUENCY: ♦♦ – Fossil sections occur in occasional limestone blocks, but recognisable examples are scattered.
CHILDREN: ♦♦ – The hilly paths include steep drops and unfenced stretches; close supervision is essential.
ACCESS – Signed paths climb from the small car park below the Gwaenysgor road. The slopes are not an all-ability route.
TYPE – Carboniferous limestone escarpment, with fossils visible in path-side blocks and historical quarry exposures.
DIRECTIONS
♦ Use the small car park at the foot of the hillside on the road from Prestatyn towards Gwaenysgor. Follow the current signs for Prestatyn Hillside and the waymarked walking route.
♦ The escarpment paths offer views over the town and occasional limestone surfaces to inspect. Choose a route suitable for the group and return on established paths; the original circuit was approximately 5 km rather than a newly measured itinerary.
♦ An onward walk to Graig Fawr is a separate extension, with its own paths and management. Check the route before continuing and do not treat nearby quarries as additional access points.
FOSSIL HUNTING
Look at naturally exposed limestone surfaces beside the signed paths. Crinoid stems often appear as small circular discs or short repeated segments; broken sections may show a central opening. Brachiopods leave curved shell outlines, while corals may show a radiating internal pattern. Many fossils remain embedded as cross-sections rather than complete specimens that could be extracted intact.
The original guide records crinoid fragments, brachiopods and corals in occasional loose blocks. These are sensible expectations for observation, but the distribution is patchy and there is no guarantee of a find. Buildings and walls may also contain fossiliferous stone: examine them visually only, without loosening, scraping or removing any part.
The historical northern Prestatyn quarries yielded small solitary corals, including Cyathaxonia and forms described as zaphrentoid, with sparse brachiopods. A small reef-like limestone body beside the hillside path had a richer recorded assemblage. Its detailed historical species list belongs to that particular surveyed exposure and should not be used to name every fossil on the walk.
Fossils in these rocks may have been transported along with carbonate sediment. A coral-shaped block is not by itself proof of an undisturbed reef in its original growth position. Record the matrix and the actual place where a fossil is seen, and distinguish a loose block from a bedrock exposure.
A hand lens and photographs with a scale are usually the most useful record. The old quarry lists, a museum specimen from the Linden Walk road cutting and fossils from nearby Graig Fawr or Teilia are separate records. They do not turn this path into a collecting itinerary for neighbouring quarries or promise their distinctive fauna here.
Significant discoveries, geological research and conservation milestones at Prestatyn Hillside.
1984 – Hillside limestone and type quarries documented
The district geological memoir described the Prestatyn Limestone, its northern hillside type quarries and the adjoining pale limestone facies. It recorded individual exposures and fossil assemblages that remain important for interpreting the walk’s rocks.
2009 – Transported carbonate deposits placed in a modern framework
A revised Carboniferous framework defined the Prestatyn Limestone Formation within the Craven Group and explained its redeposited carbonate facies. This distinguishes the hillside’s basin-side sediments from a simple in-place reef interpretation.
GEOLOGY
The northern hillside’s characteristic dark limestones belong to the late Asbian Prestatyn Limestone Formation, within the Craven Group. These basin-side deposits are distinguished from the neighbouring platform limestone succession. During the Viséan, carbonate material formed on a nearby platform and reef margin, then moved downslope into deeper water.
Graded limestone beds, finer mudstone interbeds and transported reef debris record that redeposition. Coarser material settled first during sediment flows, followed by finer carbonate mud, while quieter intervals allowed muddy layers to accumulate. Chert occurs within the succession, adding hard, often dark bands or nodules that weather differently from the limestone.
The older survey distinguished pale Gwaenysgor limestone from darker Prestatyn beds and interpreted some pale deposits as back-reef material. Later regional work emphasised transported carbonate sediment on the basin side of the reef. The historical names remain useful for understanding descriptions of the hillside, but the evidence does not justify turning Gwaenysgor into an invented formal member of the Prestatyn Limestone.
The nearby northern quarries form a partial type section with around 120 m of succession above a faulted base. That figure is not the height of a single safe face or a thickness continuously exposed on the public path. Lateral facies changes are important: the adjoining platform limestones towards Graig Fawr are not simply another bed above this walk’s dark limestone.
The Prestatyn Limestone type exposures, transported carbonate beds and historical hillside fossil records.
CRAVEN GROUP
Current BGS classification places the Prestatyn Limestone Formation in the Craven Group. The formation belongs to the basin-side succession rather than the adjacent Clwyd platform succession. The historical Dyserth Limestone Group terminology belongs to an earlier regional scheme.
Prestatyn Limestone Formation
The formation is late Asbian, within the Viséan. It contains carbonate turbidites and redeposited platform or reef debris, with fining-upward graded limestone, muddy interbeds, occasional thicker redeposited beds, transported reef blocks and chert. It is not uniformly an in-place shallow-water reef.
Northern type quarries. Quarries between SJ07078178 and SJ07188212 expose a partial type section of approximately 120 m, with a faulted base. The historical account describes dark limestone beds 0.15–0.9 m thick, shaly partings up to 0.2 m and black chert. The section total is not one accessible face, and these geological references do not imply current entry or collecting permission.
Paler Gwaenysgor beds in the historical survey. The older survey distinguished pale limestone from the darker Prestatyn beds. Lateral passage and interbedding were recorded at SJ07388235 and SJ07348238, with pale limestone and mudstone bands at SJ07368227 and SJ07428211. Historical back-reef interpretation was modified by later recognition of redeposited carbonate sediment on the basin side of the reef. Gwaenysgor is not assigned an unsupported formal member rank here.
Small path-side reef-like body. At SJ07328221 the 1984 survey described a limestone body about 2.7 m across and 1.6 m high associated with cherty beds. ‘Reef-like’ describes the historical observation; it does not prove that this body remains in original growth position under the modern resedimentation interpretation. Its present condition is not established by the historical dimensions.
Historical fauna of the path-side body. Recorded identifications are Cyathaxonia sp.; Dibunophyllum cf. bipartitum; Alitaria panderi; Antiquatonia insculpta; A. cf. hindi; Echinoconchus punctatus; Quasiavonia aculeata; Undaria?; and Straparollus dionysii. These retain the survey’s qualifications and historical nomenclature. They are not species identifications for unvouchered photographs or all loose blocks along the walk.
Quarry corals and a museum voucher. The exact Prestatyn quarries yielded Cyathaxonia, small zaphrentoid solitary corals and sparse brachiopods. The BGS catalogue separately records specimen LZA190 as Cyathaxonia cf. rushiana from the road cutting above Linden Walk. No type status or discovery date is established by that entry, and it is not a reason to encourage roadside collecting.
Neighbouring survey exposures. East of the Prestatyn–Gwaenysgor road, SJ07538169 exposed 5.8 m of bedded, partly cherty micritic limestone. At Tan-y-craig, SJ07428102 showed 3.6 m of banded limestone, with a massive-to-bedded passage at SJ07388106. These are separately located historical observations, not additional measured units continuously exposed on the northern public path.
Lateral context and scope limits. The Graig Fawr Limestone Member belongs to the adjacent platform succession and interdigitates northward with Prestatyn Limestone. It is not an overlying unit added to a single hillside column. The Meliden Station Quarry and Axton fauna, Moel Hiraddug plant-bearing beds, Gronant borehole records, Teilia flora and Pentre Chert sections are separate localities and are excluded from this walk’s fossil expectations.
Correlation diagrams are not local logs. The 1984 regional figure compares several columns and older group assignments. Its regional thickness tables and the Teilia/Pentre borehole totals do not provide a numbered bed succession along the path. No additional named member hierarchy is imposed on the exact hillside exposures.
References. Warren, P. T., Price, D., Nutt, M. J. C. and Smith, E. G. (1984), Geology of the country around Rhyl and Denbigh, BGS memoir for sheets 95 and 107, east-of-Vale-of-Clwyd and Prestatyn sections; Waters and colleagues (2009), BGS RR/09/01, section 4.7.12; BGS Lexicon, Prestatyn Limestone Formation, Craven Group and Graig Fawr Limestone Member entries; BGS Palaeosaurus, LZA190, road cutting above Linden Walk.
SAFETY
Keep to signed paths, away from cliff and quarry edges, unstable slopes and mine entrances. The ground is steep and uneven in places, with unfenced drops; supervise children closely and use footwear with good grip.
Follow current grazing and conservation notices. Keep dogs controlled around livestock, close gates and avoid trampling wildflowers or leaving paths to reach a fossil exposure. Take weatherproof clothing and allow enough time for the hilly return route.
EQUIPMENT
Take a camera, scale, hand lens, map, water and suitable walking footwear. Tools are unnecessary for observing fossils on this walk. Do not hammer larger blocks, outcrops or wall stone.
CLEANING AND TREATING
If a specimen has been obtained with permission, retain its locality record and wrap it separately. A fossil in hard limestone may be a useful section rather than an extractable whole shell; forcing the matrix away can split both rock and fossil.
Use minimal dry brushing on sound surfaces. Avoid acids, oils, polishing and aggressive tools: carbonate skeletons and fine structures can be destroyed. Unusual material is best left unprepared until a museum or specialist has advised on 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: Geology of the country around Rhyl and Denbigh
BGS: Prestatyn Limestone Formation
BGS: Carboniferous stratigraphical framework
National Landscape: Prestatyn Hillside visitor information
ACCESS RIGHTS
Prestatyn Hillside is managed for conservation by Denbighshire Countryside Service and includes a protected botanical site. Follow the signed public paths, current notices and any temporary closures. The neighbouring Graig Fawr property has separate management.
Walking access does not grant permission to remove fossils or loose stone. Ask the landowner or responsible manager before collecting; otherwise treat the visit as observation and photography. Do not hammer outcrops or larger blocks, disturb walls, dig into the slope or damage vegetation. Small size alone does not make a specimen free to take.
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 2008, Updated 2017, Edited by Jon Trevelyan 2016
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