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Introduction
Crail is a small fishing village located in south east Fife (Scotland) and provides a fascinating insight into the Carboniferous period 335 million years ago. What distinguishes Crail from the surrounding localities is the occurrence of several well preserved Arthropleura (giant centipede) trackways, which can be seen in situ in the neighbouring bay. Please note, the trackways are scientifically important and must not be collected or damaged, we ask that all visitors respect this.
(Left) View over Crail harbour from the road leading into the village. (Right) A small coffee shop provides refreshments and views over the bay.
Parking is available throughout the village and a small coffee shop provides refreshments and stunning views across the bay. Access to the beach is made alongside the western edge of the harbour (see photo above-left), this leads into the first of several small bays described below.
The geology of Crail
The rocks at Crail were formed within an expansive delta system during the Carboniferous period (Visean stage / Holkerian sub-stage), approximately 335 million years ago. Much of the rock exposed today was formed by sands and silts carried and deposited by rivers across the region. It's interesting to note that at this time the river system flowed south west, completely opposite to the present situation; the source of the rivers during this time was where the North Sea is today.
This period represents a great change in the earth's history, with land plants evolving into large trees and ferns, and amphibians, reptiles and giant flying insects inhabiting the humid forests. One of the notable inhabitants of the forest floor was Arthropleura, a giant centipede which evolved from crustacean-like ancestors and was able to grow larger than modern Arthopods because of the high percentage of oxygen in Earth's atmosphere at that time and because of the lack of large terrestrial predators.
Where to look for fossils?
Fossils can be found among the pebbles and foreshore exposures within each of the neighbouring bays west of the harbour. Heading along the beach (at low tide) the first fossil you're likely to encounter is a giant tree stump (see below-left); continuing further you'll shortly reach the site of the Arthropleura tracks (see below-right).
(Left) Giant tree stump visible in the bottom-left of the photo. (Right) Horizontal bedding and location of the Arthropleura tracks.
There are several Arthropleura tracks, the most striking of which is located above sea level in the cliff section shown above-right. The first bay ends shortly after the tracks, beyond which several more bays can be found and provide the best opportunity to collect fossils.
For more information about the features and processes controlling coastal fossil collecting locations click here.
What fossils might you find?
Crail is most famous for the occurrence of Arthropleura trackways in the cliffs and on the foreshore boulders; these impressive giant centipedes measured up to 2 meters (over 9 feet) in length and comprised of an armoured exoskeleton and dozens of sharply pointed legs running along its underside.
A model Arthropleura displayed in the Hunterian museum in Glasgow.
The spacing of the tracks at Crail indicate this particular specimen measured over 4 feet. The most impressive pair of tracks occur above the foreshore (described above), each comprising two clear uniform impressions of the creatures many feet. Given the similarity of the two tracks and the unique circumstances that led to their preservation, it's most probable that they were left by the same creature within a short time of each other (possibly the same day).
(Left) Two apparently separate Arthropleura trackways hi-res image (Right) A close-up of the tracks.
During our recent visit we observed a further two separate trackways, as shown below; these particular specimens are being subjected to extensive weathering by the sea, the result of which is apparent and a great shame. We hope that the addition of Crail to the website may serve to amplify the efforts to preserve them.
(Left) A second Arthropleura trackway on a foreshore boulder. Hi-res image (Right) A third trackway.
As well as several trackways the first bay is also host to a range of other fossils, in particular a large tree stump (below-right) and ripple marks formed in the Carboniferous sediment (below-left).
(Left) Ripple marks on the surface of a large foreshore boulder. (Right) A large tree stump on the foreshore.
Hammering is not recommended in this area, as the vast majority of finds are in situ and should be left for others to observe. Among the foreshore boulders it's possible to collect small pebbles containing evidence of trees and other vegetation present at the time; the specimens below show two separate types of tree material.
(Left) A fragment of tree bark - Lepidodendron. (Right) Another fragment of unidentified tree bark.
The most common fossils along this stretch of coast are the trunk and roots of Lepidodendron trees, which appear in situ of the foreshore. The bark is identifiable by its characteristic diamond-shaped leaf cushions, whereas the roots (known commonly as Stigmaria) are covered by a series of small pits (see below-left), from which smaller root appendages grew. Some Lepidodendron species could grow up to 40 metres; the roots spread horizontally, indicating humid environments.
(Left) Stigmaria (Lepidodendron root). (Right) A large section of unidentified tree trunk.
(Left) Stigmaria (Lepidodendron root). (Right) Stigmaria impression (Lepidodendron root)
Leaving the first bay and moving further along the foreshore, the volume of beach pebbles increases and as does the opportunity to collect fossils. If you're equipped with a hammer and chisel (see equipment) you can find a variety of fossils within them. The photo below (top-right) shows a close-up of a split pebble, within which a small bivalve shell can be made out (upper-left) alongside plant debris; the presence of these two fossils indicates the environment was densely vegetated and in immediate proximity to water.
(Left) A split beach pebble containing plant and shell remains. (Right) A close-up of the bivalve and vegetation.
(Left) Section of unidentified tree bark - Lepidodendron?. (Right) Section of tree trunk - Lepidodendron
Please note, the foreshore west of Crail is designated a Site of Special Scientific Interest (SSSI), which makes it illegal to hammer or remove any situ material.
Protecting for finds
It's important to spend some time considering the best way to protect your finds onsite, in transit, on display and in storage. Prior to your visit, consider the equipment and accessories you're likely to need, as these will differ depending on the type of rock, terrain and prevailing weather conditions.
(Left) Fossil wrapped in newspaper, ready for transport. (Right) A small compartment box containing cotton wool is ideal for separating delicate specimens.
When you discover a fossil, examine the surrounding matrix (rock) and consider how best to remove the specimen without breaking it; patience and consideration are key. The aim of extraction is to remove the specimen with some of the matrix attached, as this will provide added protection during transit and future handling; sometimes breaks are unavoidable, but with care you should be able to extract most specimens intact. In the event of breakage, carefully gather all the pieces together, as in most cases repairs can be made at a later time...continued.
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