Maer Cliff, south of Northcott Mouth, exposes steeply tilted Carboniferous sandstone and shale. Careful searching may reveal plant fragments, fish remains and traces of animal activity, while concretion-bearing black shales and contrasting sedimentary structures make this an instructive geological shore. The rocky route is tide-dependent and requires more care than the main beach.
FIND FREQUENCY: ♦♦ – Plant fragments and fish remains are generally inconspicuous; fossil-bearing shale and concretions may be covered, and complete fish are exceptional.
CHILDREN: ♦♦ – Northcott’s sandy beach is different from the uneven, cliff-backed Maer fossil shore. The latter needs close supervision and is unsuitable for young children.
ACCESS: ♦♦♦ – Approach from Northcott Mouth’s established visitor access. The walk south crosses uneven rock and depends on tide and swell.
TYPE: Cliffs and rocky foreshore; sandstone, laminated shale and concretions within the Bude Formation.
DIRECTIONS
♦ Maer Cliff lies between Northcott Mouth and the northern side of Bude. Northcott Mouth is the practical starting point for examining this shore; do not rely on a return walk from Bude across the foreshore remaining open.
♦ From the A39 at Stratton, take the road towards Poughill, also signposted towards Flexbury. Pass the church in Poughill, turn right and continue towards Maer before taking the right turn for Northcott Mouth. The shorter alternative road from the A39 into Poughill includes a very steep hill. Follow current local signs through the narrow lanes.
♦ Use the Northcott Mouth car park. The National Trust lists dawn-to-dusk opening, a 2.1 m height barrier and a donation welcome, with no overnight parking or camping. There are no toilets; the independent café is seasonal.
♦ Walk down to the beach and head south towards Maer only while the shore route is safely open. Check each narrowing and your return route before going farther. The Coast Path is a separate higher route, with uneven and sometimes steep ground; it does not provide an escape from every foreshore exposure.
♦ Original guide locality reference: 50.84791°N, 4.55439°W. This marks the collecting locality, not a parking entrance or a guarantee of safe access at that point.
FOSSIL HUNTING
Begin with naturally exposed surfaces of the dark, finely laminated shale rather than the abundant massive sandstone. Thin dark films, small scales and plant fragments can be much less conspicuous than the ripples and other structures in the surrounding rock. A hand lens and photographs taken with light falling across the surface help to show fine relief. Beach cover changes, so a productive shale band described in an older guide may be hidden on the day of a visit.
The Tom’s Cove Shale is the principal named concretion-bearing horizon in the Maer High Cliff account. The local black shale and mudstone contain distinct ironstone nodules, carbonate concretions and coprolitic pellets at different levels. Many concretions contain no recognisable fossil. Concentrate on weathered exteriors and existing broken surfaces of loose material, where collecting is permitted, rather than removing nodules from the cliff or splitting every example.
Fish remains are usually small fragments or scales. Coelacanth material identified as Rhabdoderma elegans is associated with these black-shale horizons in published Bude Formation work and was reported in the original Maer guide, but an isolated shiny flake cannot be assigned to that species. Repeated scale outlines, associated bones or fin elements are more informative. An articulated or unusually complete specimen should be photographed with a scale and left unprepared while specialist advice is sought.
Plant material is commonly flattened, dark and incomplete. Look for a consistent stem outline or organised surface pattern, rather than assuming that every black streak is plant tissue. Small spindle-shaped pellets are also recorded in the Tom’s Cove Shale and have been interpreted as coprolites. Their shape alone is not diagnostic: mineral patches and ordinary nodules can look similar. Retaining the surrounding shale and recording whether the object was loose or in place are more useful than polishing it into an isolated object.
Trace fossils record animal behaviour. BGS records horseshoe-crab, or xiphosurid, tracks in flaggy sandstone and siltstone at SS2015 0751, a few metres below the Saturday’s Pit Shale. This is a separate horizon from the Tom’s Cove concretion band. A repeated track pattern across a bedding surface is more informative than one ambiguous mark; photograph the whole visible surface and its orientation. Burrow-like markings also occur in material reported by the original guide, but do not give a species name to a partial trace without sufficient detail.
Ripple marks, grooves, load casts and upward-pointing flames of mud are important geological observations, but many were formed by moving water or soft sediment rather than animals. Sand injected into overlying mud can resemble branches. Record these structures in place and compare their relationship to bedding before deciding that they are fossils. Keep both part and counterpart of any legitimately collected loose fossil, wrap them separately, and label beach material as loose unless its original bed can be established.
A chronological record of fossil discoveries, geological research and site history at Maer Cliff.
1979 – Maer shale and track horizons documented
The Geological Survey memoir by E. C. Freshney and colleagues described the 7.5 m Tom’s Cove Shale section near Maer High Cliff, including its separate nodule, concretion and pellet levels. It also recorded xiphosurid tracks below Saturday’s Pit Shale farther south, establishing their distinct stratigraphic positions.
2013 – Repeated sediment packages logged at Maer
Nicholas P. J. Harper published a detailed Maer Cliff log showing laminated, rippled and cross-stratified sediment, black shale and contorted sandstone. Bedding-parallel faults and thrusts repeat parts of the section, making this a useful example of why visible thickness cannot simply be equated with an uninterrupted depositional succession.
GEOLOGY
The bedrock belongs to the late Carboniferous Bude Formation of the Holsworthy Group. Its resistant sandstone beds stand out between softer siltstone, mudstone and shale. The formation is assigned a Langsettian–Bolsovian age range in the BGS Lexicon, but that formation-wide range is not a precise date for every Maer bed. Older accounts use terms such as Upper Carboniferous, Silesian, Westphalian and Bude Sandstones; they should not be read as additional formations stacked above or below the rocks exposed here.
The succession records repeated changes in sediment supply and water movement. Sand arrived in substantial pulses, while quieter intervals allowed fine mud to settle. Mud-draped ripples, trough cross-stratification and hummocky structures preserve evidence of currents and wave influence. Black shale with only sparse sand or silt stringers records a very different balance of sediment supply. Lake, brackish-basin and submarine-fan interpretations have all been discussed for the wider formation. The local evidence is best explained without treating every sandstone as proof of one unchanging environment.
The Tom’s Cove Shale provides a useful marker near Maer High Cliff. Its local 7.5 m section contains ironstone nodules, a carbonate-concretion band, coprolitic pellets and a thin sandstone near the top. These features occur at different heights within the shale. The horseshoe-crab tracks farther south lie below the younger Saturday’s Pit Shale, so the two fossil records must not be combined into a single nodule-and-track bed. Neither the size of a concretion nor the height of the modern cliff measures the thickness of a fossil horizon.
Deformation gives the coast another layer of complexity. Some sand and mud moved while still soft, producing injection, flames and contorted beds; later folding, fracturing and fault movement changed the arrangement further. Many beds are now very steep or vertical; the original guide reported a local dip of about 80°, which is a historical observation rather than a uniform dip along the whole cliff. Harper’s Maer log records repeated sediment packages separated by bedding-parallel faults and thrusts. Walking across successive outcrops therefore does not necessarily mean passing once through an uninterrupted time sequence, and similar-looking shale bands need careful correlation.
Detailed geology and stratigraphy of Maer Cliff, including the limits of local correlation.
Scope and order. This account concerns the Maer shore south of Northcott Mouth. It distinguishes the BGS section near Maer High Cliff from Harper’s Log 17 farther north at Maer. The two records are described independently and are not added together as a complete local thickness. The full Northcott and Bude Sea Pool tables belong to adjoining sections and are not reproduced as a continuous Maer log.
HOLSWORTHY GROUP
The Bude Formation belongs to the Holsworthy Group, within the Culm Supergroup. Holsworthy is the preferred group name; Upper Culm Group and Upper Culm occur in older nomenclature. The group includes a much broader regional succession than the small windows exposed and described here.
Bude Formation
Sandstone alternates with siltstone, mudstone and distinctive darker shale packages. The current BGS formation age range is Langsettian to Bolsovian. Neither its regional calculated thickness of at least 1,290 m nor the full type-coast succession is exposed as one undeformed Maer cliff section. Tom’s Cove Shale and Saturday’s Pit Shale are named marker horizons within the formation; no formal member rank is imposed here.
Historical nomenclature and age limits
Bude Sandstones is an older name for the formation, while Silesian and Westphalian belong to older regional Carboniferous terminology. A suggested correlation of Tom’s Cove Shale with the Vanderbeckei Marine Band was not supported by diagnostic biostratigraphical evidence in the GCR review. It should not be converted into a secure exact-age assignment for the Maer fish-bearing horizon.
BGS section, SS2010 0780–SS2013 0772. The exposure runs from an anticline core towards Maer High Cliff. Its beds are steeply dipping to vertical. The following features belong to that window, rather than to the entire formation or to the separate Northcott measured table.
Medium-bedded sandstone background
Most of this interval consists of medium-bedded sandstone, interrupted by dark grey to black shale packages. Folding controls the present exposure; a shore distance across these beds is not automatically a true stratigraphic thickness.
Two major massive sandstone units
BGS distinguishes major massive sandstones at SS2009 0777 and SS2009 0773. They are separate mapped units in the section, without an individually stated thickness in this description. Their massive character contrasts with the finer bedding of the intervening rock.
Dark shale packages, locally up to 4.25 m
Several shale bands occur between the sandstones. The memoir records thicknesses reaching 4.25 m within this local succession; that maximum is not a uniform thickness for every dark band or for Tom’s Cove Shale itself.
Lowest described shale and injected sandstone
At SS2011 0779, an approximately 4 m shale package contains a 1 m sandstone. Irregular protrusions extend from this sandstone into the shale above. Their relationship to the parent sandstone identifies sediment deformation or injection, rather than fossil stems branching through the mud.
BGS local section at SS2013 0772. Black shale and mudstone form a 7.5 m package. The following positions are measured upwards from its base; they describe features within one shale horizon and must not be added as separate bed thicknesses.
Basal black shale and mudstone
The measured shale begins with dark fine-grained sediment beneath the first recorded ironstone nodules. The memoir does not define an independently named basal bed or a precise boundary for a separate basal subunit.
Ironstone nodules, about 1 m above the base
Ironstone nodules occur roughly 1 m above the base of the local shale. This is their stratigraphic position, not a 1 m-thick nodule bed, and they are distinguished from the carbonate concretions recorded higher in the section.
Carbonate concretions, about 1.5 m above the base
A concretion band lies about 1.5 m above the base. Individual concretions reach 0.4 m across in the BGS description. That measurement is concretion diameter, not the thickness of the band. Nodule sizes vary, and the original guide’s report of smaller examples does not establish a separate stratigraphic unit.
Coprolitic pellets, 3–3.7 m above the base
Pellets interpreted as coprolitic occur through the interval 3–3.7 m above the base. This is a fossil-bearing part of the shale, separated in the record from the lower concretion band. The objects are generally interpreted as faecal material, but identification of an individual weathered pellet requires more than its outline.
Upper shale and near-top sandstone
Shale and mudstone continue above the recorded pellet interval, with a thin sandstone near the top of the 7.5 m package. Its precise thickness and height are not given, so no numerical top-sandstone interval is created here.
Clay mineralogy and the overlying grey shale
The BGS mineralogical account records vertical Tom’s Cove Shale at SS2010 0772 containing chlorite and kaolinite, rarely together in one sample, within a predominantly illitic shale suite. It places a non-marine grey shale 0.5 m above the marker shale and reports more kaolinite in it. The suggested connection between clay mineral variation and changing salinity is an interpretation; 0.5 m is the stated separation, not the thickness of that grey shale.
Other correlated Tom’s Cove exposures
BGS records a laminated concretion at Curtis’s Rock, SS2019 0859, and folded occurrences in cliff-top synclines at SS2018 0826 and SS2018 0816. These positions help correlate the marker but are not directions to climb the cliffs. The separate pyritised-fish occurrence at SS2013 0654 is on the Bude Haven foreshore and is not relabelled as a Maer discovery.
Log 17, Maer Cliff, SS200082. Figure 3.4 shows about 6.4 m of exposed rock below Tom’s Cove Shale, with repetitions bounded by bedding-parallel faults. The descriptions below follow the graphic upwards, including all its principal sedimentary and structural observations. They are descriptive intervals, not twelve newly named beds, and the exposure thickness includes repeated rock. No individual thickness is inferred from the size of a symbol or comment box.
Log 17: basal planar lamination and ripples
Faint planar lamination is interbedded with sand-and-silt ripples draped by mud. Harper considered tidal or minor wave influence, with a turbidite alternative, rather than treating the ripple fabric as a unique environmental indicator.
Log 17: lower trough cross-stratification
Mud-draped trough cross-stratification succeeds the basal laminated and rippled material. Mud rip-up clasts occur towards the top, recording erosion and incorporation of already deposited mud during sand movement.
Log 17: lower bedding-parallel fault
A bedding-parallel fault truncates the lower beds near the first metre of the plotted log. It is a structural break, not a shale bed or a depositional hiatus of measured duration.
Log 17: thicker trough-cross-stratified package
Above the lower fault is a thicker sand-and-silt package with mud-draped trough cross-stratification. Hummocky cross-stratification occurs near its top. Quartz veins cut across the sedimentary structures; these later mineral-filled fractures are not extra beds within the original depositional sequence.
Log 17: repeated planar lamination and ripples
Faint planar lamination and mud-draped sand-and-silt ripples recur above the thicker package. The graphic explicitly identifies this as part of a repeated succession, so it cannot be counted as an independent repetition of depositional conditions without first allowing for fault movement.
Log 17: repeated trough beds and thrust
Another mud-draped, trough-cross-stratified interval has hummocky structures at bed tops and a bedding-parallel thrust. Together with the repeated laminated and rippled material below, it preserves the structural duplication shown in the figure.
Log 17: thin rippled and planar-laminated package
A further thin interval combines faint mud-draped sand-and-silt ripples with planar lamination. It is retained separately because the source distinguishes it above the repeated trough-cross-stratified package and below the main black shale.
Log 17: planar black shale and sample 64382
Planar-laminated black shale contains very little coarse sediment. Harper interpreted this as an almost complete reduction in incoming sand and silt, and located rock sample 64382 within this interval. The sample number is an identifier, not a fossil species, bed number or additional horizon.
Log 17: black shale with sand and silt stringers
The next black-shale interval includes thin sandstone and siltstone stringers. The source considers a possible turbiditic origin for these minor coarser inputs, but does not establish a separate named marine band or a fossil correlation.
Log 17: contorted sandstone and sample 64383
More massive sandstone contains injected mud and flame structures at its base. The sandstone is also contorted; Harper suggested incomplete dewatering as a possible cause and considered a turbidite interpretation. Rock sample 64383 belongs to this sandstone. These early sediment-deformation features must be distinguished from the faults which repeat the succession.
Log 17: upper stringer-bearing black shale
Above the contorted sandstone, planar-laminated black shale again contains sandstone and siltstone stringers. Its separate position in the logged section is retained without treating similar lithology as proof of a unique coast-wide bed.
Log 17: upper bedding-parallel thrust repetition
At the top of the graphic, black shale and contorted sandstone are repeated above another bedding-parallel thrust. The section therefore contains structural duplication at more than one level. Its approximately 6.4 m plotted extent is neither a fault-corrected depositional thickness nor an extra 6.4 m to add to the separate BGS 7.5 m Tom’s Cove section.
Other observed sedimentary structures
The original Maer account also describes graded beds, pseudo-nodules, water-escape structures and slumped sediment. Grading records changes in grain size through a deposit; pseudo-nodules and flames can form as denser sand sinks into wetter mud, while escaping pore water can disrupt the layering. These observations complement the measured logs but do not establish additional named beds, exact thicknesses or fossil horizons.
Historical sideritic and septarian nodules
The original guide described sideritic septarian nodules within shale, about 15 cm thick, with reported burrows, plant remains and fish. This is a historical description of the nodules, not a measured 15 cm shale-bed thickness. Its exact position is not securely correlated with the separate BGS ironstone and carbonate-concretion levels above. The 15 cm observation must also remain distinct from the BGS maximum concretion diameter of 0.4 m.
Below and within Saturday’s Pit Shale. These are separate local observations farther south, not subdivisions of the Tom’s Cove Shale or extensions of Harper’s numbered log.
Xiphosurid-track-bearing flaggy beds
At SS2015 0751, flaggy sandstone and siltstone bear xiphosurid tracks a few metres below Saturday’s Pit Shale. The fossils record locomotion across sediment. The memoir does not provide an exact thickness for the track-bearing surface, and it must not be moved down into the Tom’s Cove concretion band.
Southern Saturday’s Pit Shale exposures
BGS records 3.66 m of shale at SS2015 0750 and 3 m at SS2015 0730, with concretions approximately 1 m above the respective bases. Folding repeats the shale at SS2015 0742. These are separate local measurements and outcrops, not three successive shale beds. The more detailed Saturday’s Pit fish-bearing section at the swimming pool belongs to the adjoining Bude locality.
Depositional and structural interpretation
The local ripple, cross-stratified and laminated facies preserve changing water movement and sediment input. Wider Bude Formation interpretations include a large fresh-to-brackish lake with marine incursions and a submarine-fan setting. Harper retained alternative explanations for several Maer structures. Early deformation of wet sediment and later tectonic folding or fault repetition both matter; neither a single environmental label nor a simple upright stack captures all the evidence.
References
Freshney, Edmonds, Taylor & Williams (1979), Geology of the country around Bude and Bradworthy, BGS sheets 307 and 308; Maer High Cliff and southern Northcott sections
Harper (2013), Assessing the mechanical state of sediment and rock during deformation: the example of the Bude Formation, South-west England, University of Leeds thesis; Figure 3.4, Log 17, p. 57
BGS Lexicon: Holsworthy Group
BGS Lexicon: Bude Formation
Cleal & Thomas (1996), Bude Coast, British Upper Carboniferous Stratigraphy, Geological Conservation Review 11; broader coastal context
UK Fossils: original Maer Cliff guide; original observations and navigation
Craven & Lloyd (2023), structural and stratigraphic research on the Bude coast; regional context
SAFETY
The rocky shore narrows beneath cliffs and around projecting ribs of sandstone. Tide height, swell and weather affect access, so there is no reliable fixed number of hours either side of low tide. Check the forecast before setting out, work with a generous return margin, and turn back before waves threaten a narrowing. Do not expect to climb a cliff if the shore route closes.
Keep clear of cliff bases, overhangs and fresh falls. A block or apparently firm face does not prove that the rock above is stable. Wet shale, seaweed and steep sandstone ribs are slippery, while broken rock can be sharp. Avoid crossing deep gaps or jumping between blocks.
Northcott Mouth’s seasonal RNLI cover is for the beach in peak summer; it does not make remote Maer exposures supervised or safe. Phone reception can be patchy. Tell someone your route and expected return, carry a charged phone, and keep children away from cliffs and exposed rocky margins.
EQUIPMENT
Wear sturdy footwear with reliable grip and carry current tide and weather information. A hand lens, camera, scale and notebook suit an observation visit. A small rigid box and individual wrapping protect any fragile loose material whose collection is permitted. Do not assume that a hammer or chisel may be used simply because shale and concretions contain fossils.
CLEANING AND TREATING
Support thin shale on a rigid base and keep any part and counterpart together under one label, with the exact locality and whether it was found loose. Photograph delicate fish remains, plant films and trace surfaces before handling further. Use a soft dry brush first; avoid soaking laminated or crumbly shale, and allow wet specimens to dry gradually rather than heating them.
Do not use acid on carbonate concretions, polish away their surfaces, or varnish delicate fossil films. A promising fish-bearing concretion is better retained in matrix for specialist assessment than forced open along a new break. Material showing pyrite deterioration or unstable clay needs individual conservation advice; the same drying or coating treatment is not suitable for every Maer specimen.
IDENTIFY YOUR FINDS
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FURTHER READING
Jens Lehmann (2020), Fabulous folds: Variscan tectonics in southwest England, Deposits Magazine; regional background
Freshney, Edmonds, Taylor & Williams (1979), Geology of the country around Bude and Bradworthy, BGS sheets 307 and 308; Maer High Cliff and southern Northcott sections
BGS Lexicon: Bude Formation
Harper (2013), Assessing the mechanical state of sediment and rock during deformation: the example of the Bude Formation, South-west England, University of Leeds thesis; Figure 3.4, Log 17, p. 57
Cleal & Thomas (1996), Bude Coast, British Upper Carboniferous Stratigraphy, Geological Conservation Review 11; broader coastal context
Craven & Lloyd (2023), structural and stratigraphic research on the Bude coast; regional context
National Trust: Northcott Mouth visitor access, parking and facilities
Museums, Libraries and Archives Council (2004), Standards in the Museum Care of Geological Collections
ACCESS RIGHTS
Approach through the established Northcott Mouth visitor access and follow current landowner and Coast Path notices. Public access to the shore does not itself authorise fossil removal, excavation or hammering. Check the current rules before taking loose material, and leave the cliff and in-situ concretions undamaged.
This coast includes the officially designated Bude Coast SSSI and Duckpool to Furzey Cove SSSI. Check the actual mapped boundary at the part of the shore you intend to examine. A place-name or a single guide coordinate is not enough to establish the designation or collecting conditions of every Maer exposure.
Original guide’s designation document (historical copy; check current notices and the official site record above): SSSI Information – Maer Cliff
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