Giant arthropod trackways and fossil trees preserved where they grew make the Carboniferous shore southwest of Crail harbour a remarkable place to explore. The sandstone ledges record ancient land surfaces, while intervening marine beds reveal repeated incursions of the sea.
FIND FREQUENCY: ♦♦♦ – A rewarding shore for observing fossil roots, trunks and trackways; visibility varies with sand, seaweed, erosion and tide.
CHILDREN: ♦♦♦♦ – The harbour beach offers an easier introduction, but the fossil ledges require careful supervision and are unsuitable for pushchairs.
ACCESS: ♦♦♦ – A short approach from the village leads to uneven sandstone platforms and boulders.
TYPE: Foreshore bedding planes and low coastal exposures; plan a visit for observation and photography.
DIRECTIONS
♦ Approach Crail harbour from the village, using lawful parking and following the signs and restrictions displayed locally. Keep harbour operations and residential access clear.
♦ Walk towards the harbour beach, then follow the shore southwest towards the first sandstone ledges. This guide concerns the fossil shore southwest of the harbour, not Roome Bay or Fife Ness to the northeast.
♦ Keep to the near-harbour fossil ledges for the visit described here. The geological account uses the published section between Crail Harbour Fault and Pans Fault; it is not a through-walk to Anstruther or permission to continue over damaged ground.
♦ Original harbour approach reference: 56.25748°N, 2.62758°W. Check the tide, current coastal-path notices and signs before setting out; turn back if the shore route is unsafe.
FOSSIL HUNTING
Crail is particularly valuable for fossils that retain their relationship to the rock around them. Rather than searching for a bagful of specimens, look across the sandstone bedding planes for the outlines of roots and trunks, and for the paired trails of a large walking animal. An overview photograph followed by close-ups with a scale records much more useful information than a detached fragment. Leave the trees and trackways intact.
The plant remains include the rooting structures of tree-sized lycopsids, commonly described as Stigmaria. Broad branching roots and the smaller marks left by their rootlets can be traced across exposed surfaces. The old guide used the name Stigmaria ficoides; isolated marks are best recorded more cautiously unless their diagnostic features are clear. These are names for fossil rooting organs, rather than a secure identification of the entire tree. Some trunks stand in their original growth position, providing a striking contrast with broken plant fragments transported into younger sediment.
The published geological section places large upright tree stumps in sandstone above the Westland Skelly Marine Band. The original visit described a conspicuous stump beyond the harbour’s sandy beach and roots on several sandstone ledges. Use that description as an introduction to the kind of feature to look for, rather than a guarantee that one numbered ledge or every photographed surface will be exposed on a later visit. Sand, seaweed and coastal erosion continually alter what can be seen.
The broad paired trackways are trace fossils: impressions of the animal’s movements, rather than its body. A scientifically illustrated Crail example is assigned to Diplichnites cuithensis, with an outer width of 47 cm and an inner width of 33 cm. Those measurements belong to that particular trackway. Its likely maker was Arthropleura, an enormous extinct relative of millipedes. Look for repeated sets of small impressions arranged in two bands; a random crack or isolated hollow is not enough to establish a trackway. Low-angle natural light can make shallow relief easier to distinguish without touching the rock.
Marine fossils tell a different part of the story. At the Pans Marine Band, the geological survey recorded fossils in lenses at the top of a sandstone, including bivalves, gastropods, bryozoans and crinoid fragments. Historical identifications include Sanguinolites plicatus, Sanguinolites tricostatus and Wilkingia elliptica. These are documented records from the horizon, not a promise of abundant exposed specimens today. The fossiliferous shale described by early workers was already obscured when the later survey account was compiled.
The Crail Harbour Marine Band contains a richer marine association in mudstone and limestone. Shell outlines and fragments may represent brachiopods or bivalves, while small discs and short jointed pieces are crinoid stems. Bryozoans, gastropods and an orthocone cephalopod were also recorded. The basal crinoidal limestone is especially useful for recognising the marine character of the bed. Examine naturally exposed surfaces with a hand lens and photograph the enclosing bed as well as the fossil; do not excavate the cliff or split blocks to search for the historical fauna. The detailed section below distinguishes these marine horizons from the plant-bearing sandstones.
A chronological record of geological research and fossil observations on the shore southwest of Crail harbour.
1861 – An early marine-band correlation
Brown described a fossiliferous horizon south of Crail during his study of the Fife coast. Later geological work considered that he had probably encountered the Pans Marine Band, although he correlated it with a younger crinoid-rich horizon. The record illustrates both the early recognition of marine incursions and the difficulty of tracing similar beds along the coast.
1902 – The Pans horizon placed in its wider succession
Geikie recorded the marine bed near the base of the southwest Crail section and correlated it with the horizon now known as the Cuniger Rock Marine Band. That correlation was supported by later examination of the local fauna, helping establish the position of the Pittenweem succession at Crail.
1977 – A detailed account of the fault-bounded shore
Forsyth and Chisholm described the approximately 180 m section between Pans Fault and Crail Harbour Fault, distinguishing the Pans, Westland Skelly and Crail Harbour marine bands. Their account documented upright tree stumps above Westland Skelly and the rich fauna of the harbour marine bed, providing a framework for interpreting the fossil ledges.
2017 – Trees and trackways illustrated for visitors
An illustrated account brought together photographs and descriptions of the southwest Crail trees, rooting structures and giant arthropod trackways. It provides a dated record of the exposed features rather than evidence that they were first discovered that year.
2021–2022 – A Crail trackway included in modern arthropod research
Research first published online in 2021 and issued in a 2022 journal volume illustrated a Crail Diplichnites cuithensis trackway with outer and inner widths of 47 cm and 33 cm. Its comparison with other giant arthropod traces supported Arthropleura as the likely maker. The publication date does not establish the date the trackway was discovered.
GEOLOGY
The shore southwest of Crail harbour exposes sedimentary rocks of the Strathclyde Group, chiefly the Pittenweem Formation of Early Carboniferous, Viséan age. The formal formation is assigned to the Asbian. The published Crail section lies between the Pans Fault and Crail Harbour Fault and contains about 180 m of strata. That figure is the stratigraphic thickness of the fault-bounded section, not the height of the cliffs or the length of the walk. Almost all of it lies above the Pans Marine Band and belongs to the Pittenweem succession; the lowest approximately 7 m lies below that boundary.
Sandstone, siltstone and mudstone alternate with thinner carbonate beds and occasional coal. The plant-bearing and rooted surfaces record episodes when sediment supported vegetation, while the shelly marine bands mark incursions of the sea. The contrast is central to understanding the shore: a tree in growth position, an animal’s trail and a crinoid-bearing limestone need not represent the same environment or the same moment. Repeated environmental changes produced a layered record rather than a single fossil assemblage spread uniformly through every rock.
The strata dip eastwards and northeastwards, bringing different levels to the present foreshore. Resistant sandstones form prominent platforms, whereas softer muddy beds are more easily eroded or concealed. Three named marine horizons help correlate the section: Pans, Westland Skelly and Crail Harbour. Correlation of the middle band remains tentative, and lateral variation means the sandstone and carbonate beds should not be matched one-for-one with a neighbouring locality’s log. The Crail sequence is notably sandier and contains more bedded dolomite than the equivalent interval farther southwest near Anstruther.
Some strata are reddened, and the survey described partial replacement of certain coal seams by limestone. These features add to the history of alteration after deposition, but do not turn the shore into a uniform limestone succession. The faults also limit the section: rocks northeast of the harbour and more distant fossil localities require separate descriptions. The chart and expanded account below refer specifically to the southwest Crail section, retaining the distinction between measured geological relationships and changing present-day exposure.
A closer look at the rocks and fossil-bearing beds at Crail, from Pans Fault to Crail Harbour Fault.
Scope and structure
The published southwest Crail section extends between Pans Fault [NO 6065 0654] and Crail Harbour Fault [NO 6135 0742]. About 180 m of strata dip eastwards and northeastwards. These are the limits of a geological section, not a statement that every bed is continuously visible or safely accessible today. The named marine bands below provide the principal stratigraphic controls; the shore northeast of the harbour, including Roome Bay, is outside this account.
STRATHCLYDE GROUP
The Early Carboniferous succession combines sandstone, siltstone and mudstone with thinner limestone and dolomite beds and occasional coal. Rooted horizons and upright trees record vegetated surfaces; marine bands contain a contrasting shelly fauna. These changing environments recur through the section. Historical accounts called the wider succession the Calciferous Sandstone Measures and used “Pittenweem Beds” for the interval now treated within the modern Pittenweem Formation framework.
Lowest beds below the Pans Marine Band — approximately 7 m
The lowest approximately 7 m of the fault-bounded section lies beneath the Pans Marine Band and is excluded from the Pittenweem interval in the published correlation. It forms part of, rather than an addition to, the approximately 180 m total. The local description does not warrant assigning a complete neighbouring Anstruther succession, or invented member subdivisions, to these few metres.
Pittenweem Formation
The modern formation is assigned to the Asbian part of the Viséan. Regionally, its base is defined at the Cuniger Rock Marine Band and its top at the St Andrews Castle Marine Band. Those formal boundaries are not identical to the limits of this fault-bounded walk. At Crail, correlation of the Pans Marine Band with the Cuniger Rock horizon places nearly all the measured section in the Pittenweem succession. No formal member is required to describe the local named horizons.
Pans Marine Band [NO 6077 0666]
This horizon lies about 7 m above the base of the Crail section. Geikie described it in shale in 1902, but that shale was no longer exposed when the later geological survey account was compiled. Marine fossils were instead obtained from lenses at the top of the underlying sandstone. The fauna supports Geikie’s correlation with the Cuniger Rock Marine Band. Brown’s 1861 description probably included this horizon, although he correlated it with the younger marine bed then known as the “line of lower encrinites”. Neither historical account guarantees that the same fossiliferous surface is visible now.
The survey’s historical records from the Pans horizon include bryozoans, crinoid columnals, gastropods and bivalves. Examples include Euphemites sp., Retispira?, Aviculopecten subconoideus?, Edmondia cf. unioniformis, Naiadites cf. crassus, Sanguinolites plicatus, Sanguinolites tricostatus, Schizodus, Streblochondria and Wilkingia elliptica. The question marks and comparative identifications belong to the published records; this is not a newly revised modern species checklist.
Intervening sandstone, muddy beds and carbonates
The strata between the principal marine markers are not a uniform block of sandstone. They include the alternating sandy and muddy sediment, bedded dolomite and occasional coal characteristic of this section. Compared with the equivalent interval near Anstruther–Pathhead, Crail has more sandstone and more bedded dolomite, despite a broadly comparable spacing of the major marine horizons. Some beds are reddened and a few coal seams are partly replaced by limestone. The published correlations should therefore not be used to copy every bed or thickness from the neighbouring section.
Westland Skelly Marine Band [NO 6109 0718]
The band lies about 93 m above the base of the section; this is its stratigraphic position, not its thickness. It contains a sparse molluscan fauna. The geological survey considered it probably equivalent to the Kirklatch Marine Band, but retained that correlation as tentative. A precise thickness or a richer site-specific species assemblage should not be inferred from the better-known marine bands above and below it.
Tree-bearing sandstone above Westland Skelly
Large tree stumps are preserved in growth position in the sandstone overlying the band. These are particularly informative because the upright remains retain evidence of the vegetated surface and its burial. Rooting structures described as Stigmaria occur on the sandstone bedding planes, while other plant fragments may have been transported. A rooting-organ name does not by itself identify the biological species of the whole tree.
Crail Harbour Marine Band [NO 6105 0739] — approximately 3 m
Near the top of the section, the band consists of about 3 m of mudstone containing bands of ironstone and decalcified limestone. A crinoidal limestone approximately 0.30 m thick forms its base. It has a rich marine fauna including brachiopods, molluscs and crinoids, resembling the Pittenweem and Witch Lake marine-band assemblages. The survey noted that this bed was absent from Geikie’s 1902 description and suggested it had then been concealed by a grassy slope; that is an explanation of changing exposure, not a secure date for its discovery.
Historical records include Composita cf. ambigua, Lingula mytilloides, Orbiculoidea, an orthotetoid brachiopod, Productus cf. redesdalensis, bryozoans, gastropods, diverse bivalves, an orthocone cephalopod, crinoids and the echinoid Archaeocidaris urii. These occurrences establish the marine character of the horizon. Their historical nomenclature and qualifiers are retained; no claim is made that all names have undergone a modern revision or that every fossil remains readily visible.
Trackway-bearing surfaces: documented occurrence without an invented bed correlation
A Crail trackway illustrated in modern research is assigned to Diplichnites cuithensis in the Pittenweem Formation. That figured example has a 47 cm outer width and 33 cm inner width. Arthropleura is the inferred maker, not a co-occurring body fossil or a biological species established by the footprints. The available exact-locality evidence does not place every photographed Crail trackway at a numbered bed or demonstrate that all tracks occur on a single surface, so no such correlation is imposed here.
References
Forsyth, I. H. & Chisholm, J. I. (1977). The geology of east Fife, Crail section, Figure 4, palaeontology and Appendix 1.
Dean, M. T., Browne, M. A. E., Waters, C. N. & Powell, J. H. (2011). Pittenweem Formation: Carboniferous lithostratigraphical framework.
Davies, N. S., Garwood, R. J., McMahon, W. J., Schneider, J. W. & Shillito, A. P. (2022; first published online 2021). The largest arthropod in Earth history, especially the Crail trackway in Figure 12B.
SAFETY
Visit in calm weather with a suitable falling tide and allow time to return before the water rises. Sloping sandstone, loose boulders and seaweed can be extremely slippery. Wear footwear with good grip and avoid scrambling onto wet outer ledges or approaching the water’s edge in a swell.
Low cliffs and a path above the shore do not guarantee a safe escape everywhere. Coastal erosion can change both the foreshore and the path; check current Fife Coast and Countryside Trust notices, follow barriers and never cross a damaged section. Keep away from unstable cliff edges and the foot of loose faces. Children need close supervision on the platforms.
EQUIPMENT
Sturdy footwear, weatherproof clothing, a charged phone, tide information and a hand lens are the most useful equipment. Bring a camera and a small scale for photographs. A notebook helps record the bed, location and direction of a trackway; do not chalk, paint or scratch the surface to make it stand out.
This is an observation-led visit. Hammers, chisels and tools for clearing or excavating the rock are unnecessary for viewing the exposed roots, trees and trackways.
CLEANING AND TREATING
Leave in-situ fossils untouched. Do not brush, scrub, wash, coat or make moulds of the trackways and trees: shallow impressions and weathered surfaces can be damaged. Use natural light and photographs to study them, and seek specialist advice if an important surface appears at risk.
If a separate specimen has been obtained with the necessary permission, keep its locality and bed information with it and favour minimal preparation. Fragile mudstone can split or crumble when wetted; avoid soaking, acids, bleach and varnish. Leave potentially important specimens unprepared for specialist assessment.
IDENTIFY YOUR FINDS
Need help identifying a fossil? Share clear photos, where you found it and its size with the community.
FURTHER READING
Arthropleura: a prehistoric bug hunt at Crail (Deposits Magazine)
The geology of east Fife: Crail section and fossil records (BGS)
Pittenweem Formation: modern stratigraphic framework (BGS)
Arthropleura and its trackways: Davies and colleagues (2022)
Scottish Fossil Code (NatureScot)
ACCESS RIGHTS
The exposed trees and trackways are best appreciated in place. Photograph them without damage and do not remove them. Permission to walk on the coast does not itself give permission to take fossils; obtain the relevant rights-holder’s permission before any removal.
Protected-site boundaries change along this coastline. The near-harbour southwest ledges described here lie in the mapped gap between the Firth of Forth SSSI to the northeast and Barnsmuir Coast SSSI farther southwest. Do not extend this description to every shore called Crail, or treat the gap as collecting permission. Check the exact location and any applicable protected-site requirements if continuing beyond the immediate fossil ledges.
Follow the Scottish Fossil Code. Respect wildlife, land management and other visitors, and report scientifically important discoveries with photographs and their precise geological context rather than attempting to extract them.
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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