Folklore of fossil molluscs

The final article of this series on fossil folklore focuses on molluscs, excluding the ammonites, which were covered earlier (see Fossil folklore: ammonites in Deposits, Issue 46, pp. 20–23). Molluscs are second only to arthropods in the number of species living today and the resistant calcareous skeletons possessed by the majority of species accounts for their extremely rich fossil record. Most fossil molluscs belong to one of three major groups – bivalves (oysters, clams and so on), gastropods (snails and slugs) and cephalopods (ammonites, belemnites and so on). Added to these are a few minor groups, such as the monoplacophorans and scaphopods (tusk shells).

Fossil molluscs are usually recognisable instantly as belonging to this phylum because of their close similarities with the shells of familiar species of modern molluscs. Some, however, are not quite so straightforward. These are more likely to have been the sources of fanciful stories about their origins and significance. Among the more obscure ancient molluscs are those dubbed ‘difficult fossils’ by Martin Rudwick in the context of the early history of palaeontology and doubts over the origin of fossils. They include the solid internal casts (steinkerns) formed by lithification of sediment enclosed by the shell and subsequent loss of the defining shell itself. In addition, there are some mollusc fossils – notably belemnite guards – that bear little resemblance to any living species, adding to their enigmatic nature.

Fig. 1. Five belemnite guards oriented as though they are projectiles flung down from the sky in the manner of ‘thunderbolts’. Belemnitella minor from the Cretaceous Paramoudra Chalk of Norfolk.

Belemnites: thunderbolts and Devil’s Fingers

The first fossils I ever came across were belemnites from the Jurassic Kellaways Rock, collected while on a boyhood adventure following the course of the disused Hull and Barnsley Railway that ran at one point alongside South Cave Station Quarry. I took them home not knowing what they were and was told by my father that they were ‘thunderbolts’. Like many of his generation who had not been educated about fossils, he believed that belemnites were hurled to the ground from the sky during thunderstorms. The streamlined, missile-shape of belemnite guards seems consistent with this idea (Fig. 1). And to add credence to this notion, the heavy rain associated with thunderstorms does occasionally wash away the topsoil and bring fossils such as belemnites to the surface, almost as though they had come from the sky, as recounted by Oakley (1974). Indeed, the name belemnite is derived from the Greek Belemnon, meaning dart or javelin. According to an East Anglian horseman, “As the sun draws up water so the clouds draw up substance from the earth – sulphur and so on. When there’s a clap o’thunder, down all this comes as thunderbolts” (Evans, 1966, p. 131).

The striking shapes of belemnite guards, coupled with their robustness that imparts a high fossilisation potential, has led to a plethora of folkloric names in addition to thunderbolts. In some regions of England, they are known as Fairies’ Fingers, Devil’s Fingers or Saint Peter’s Fingers (Bassett, 1982; Duffin and Davidson, 2011). The earliest mention of belemnites in Scotland dates from 1703, in which they are referred to as botstones (Martin, 1703). Belemnites are known by numerous different names in German folklore, including Alpschoß (nightmare shot), Fingerstein (finger stone), Gespensterkerze (ghostly candle) and Katzenkegel (cat’s skittle) (Hegele, 1997). Scandinavian folklore envisages belemnites as candles belonging to elves, gnomes and pixies, hence the Swedish name Vetteljus (Gnomes’ Lights). They were believed to protect unchristened children from being transformed into changelings by trolls (Duffin, 2008). In Chinese folklore, belemnites are known as Jien-shih (sword stones).

Fig. 2. Longitudinal section of the Early Jurassic belemnite, Acrocoelites, showing the chambered phragmocone (slightly crushed and displaced to the right) above the guard.

There are several records of belemnites recovered from archaeological sites. Oakley (1974) described a Bronze Age burial site in Yorkshire where a belemnite was found with a female skeleton, seemingly a testament to the cult status of these fossils. Fragments of altered amber-coloured belemnites with fine perforations, which may have been used as charms, were found at a 20,000-year-old archaeological site known as Kostenki 17 on the Don River in Russia (Boriskovskii, 1956). Objects resembling belemnites appear in ancient Egyptian hieroglyphic inscriptions symbolising the god Min. According to Newberry (1910), fossil belemnites and certain arrowheads were cult-objects in the Egyptian Middle Kingdom, representing thunderbolts and, by association, Min.

Belemnites were once believed to have medicinal qualities, and were used as cures for both rheumatism and sore eyes in humans and horses. The treatment for horses involved crushing the fossils into a dust that would then be blown into the eyes of the animal. In Scotland, they were steeped in water and employed to cure horses of the worms that caused distemper (Oakley, 1974). They were also used to keep a person from being struck by lightning or bewitched by demons from the sky (Kennedy, 1976).

Belemnites are in fact the internal shells of an extinct group of cephalopods resembling modern squid, but differing in having hooks rather suckers on their arms. Their true affinity is unclear from the bullet-shaped guard alone – the coarse, radiating calcite crystals forming the belemnite guard could be taken to suggest an inorganic origin like the crystals in a geode. More complete specimens preserve the phragmocone (Fig. 2). This chambered shell, which is constructed of the readily dissolved mineral aragonite, fits into a conical depression in the blunt end of the guard and closely resembles the chambered shells of such cephalopods as the living nautilus, providing crucial evidence for the true affinities of these Jurassic and Cretaceous animals.

Fig. 3. ‘Pagoda Stone’, a longitudinally sectioned orthoconic nautiloid from the Ordovician of China.

Pagoda stones

Longitudinal sections through Palaeozoic orthoconic nautiloids are known in China as Pagoda Stones (bao-ta-shih), because of their vague resemblance to the tiered towers found in many temples (Fig. 3). The abundance of these fossils explains the origin of the name Pagoda Formation for an Ordovician deposit in South China.

Devil’s toenails

‘Devil’s toenails’, shells of the Jurassic oyster Gryphaea, are among the most abundant fossils found in the British Jurassic (Fig. 4). The calcite shell of Gryphaea is thick and survives weathering and erosion of the sediments in which it is fossilised. It is also sufficiently resilient to have endured transportation by rivers and Pleistocene glaciers – eroded specimens of Gryphaea are often found in river gravels and glacially deposited boulder clays in regions of England, such as Suffolk and Gloucestershire.

The robust, curved left valve of Gryphaea, marked with prominent growth bands, superficially resembles a thick toenail. It is unclear whether Gryphaea shells were once believed to be the actual toenails of devils or just that they corresponded with the popular conception of what a devil’s toenail ought to look like.

Devil’s toenails are particularly common in the Lower Jurassic rocks around Scunthorpe, formerly quarried intensively for the iron ore that was economically important for this Lincolnshire town. They feature in the town’s coat of arms, adopted in 1936 (Fig. 5). Knell (1988) quoted a passage from a diary written on 10 April 1696 by a local man, Abraham de la Pryne, which says that powdered Gryphaea was used to cure ‘… a horse’s sore back …’.

Fig. 4. A devil’s toenail oyster, Gryphaea, from the Early Jurassic of Gloucestershire.

In Scotland, fossil Gryphaea shells are known in Old Gallic as clach crubain, translated as ‘crouching shell’ (Oakley, 1974). They were apparently used in the seventeenth and eighteenth centuries to cure pain in the joints. Oakley made the interesting point that their contorted appearance is suggestive of painful joints, an example of sympathetic medicine (‘like cures like’).

Stone cores

The fossil moulds of bivalves were puzzling objects to early naturalists and common people alike. This preservational style is particularly characteristic of species of bivalves that had aragonitic shells. Unlike the more stable calcite shells found, for example, in Gryphaea, aragonite is routinely dissolved by pore waters passing through the rock, leaving spaces where the shell was formerly located surrounding a hardened sediment core. This core is an internal mould, often known by the German name ‘steinkern’. Steinkerns are solid objects that may fall out of the rock cleanly when it is broken open. The often bizarre and vexing appearance of bivalve steinkerns led to misconceptions about their origins, and spawned the names ‘Osses ‘Eds and Bulls’ hearts by which they are known in folklore. Glørstad et al. (2004) described a remarkable steinkern of the Ordovician bivalve Cyrtodonta from a Mesolithic site in south-eastern Norway that had been deliberately collected and subsequently sculpted to emphasize its female human ‘attributes’.

‘Osses ‘Eds

Steinkerns of a group of bivalves common in the Jurassic of southern England when viewed in a particular orientation vaguely resemble the heads of miniature horses (Fig. 6). The ‘eyes’ of the horse are actually moulds of scars left by the muscles that originally closed the valves together, and the ‘ears’ are the pointed beaks of the two valves. The Oxford naturalist Robert Plot (1677) referred to examples of these fossils from Headington near Oxford as ‘Hippocephaloides’ alluding to their horse head-like shape (Fig. 7). They are now known by the scientific name Myophorella hudlestoni.

Steinkerns of a related trigoniid bivalve (Myophorella incurva) are conspicuous in the Portland Stone of Dorset, particularly in a level called the ‘Roach’, which is frequently used decoratively as a facing stone on buildings, for example, the Economist Buildings in the City of Westminster. Quarrymen on the Isle of Portland speaking in local dialect knew them as ‘Osses ‘Eds.

Fig. 5. The coat-of-arms of Scunthorpe, depicting two shells of Gryphaea over the chain in the shield.

Bulls’ hearts

Another type of bivalve steinkern from the British Jurassic has been called a Bull’s heart (Fig. 8). Like ‘Osses ‘Eds, these were found by Robert Plot at Headington, who referred to them as ‘Bucardites’. They are now known by the scientific name Protocardia. Their resemblance to a heart becomes apparent when the fossils are viewed from the side, with the mould of the left valve on one side and that of the right valve on the other.

Evidence that fossils of the same type have long been known to humankind comes from the discovery of a Protocardia steinkern in a Bronze Age barrow (burial mound) at Aldbourne in Wiltshire (Oakley, 1974). This barrow was built on the Chalk and yet the fossil comes from the underlying Upper Greensand, and must have been collected and taken to the site of the barrow.

Fig. 6. Example of an ‘Osses ‘Ed of folklore – the internal mould (steinkern) of the bivalve Myophorella incurva from the Late Jurassic of Portland, Dorset.
Fig. 7. Robert Plot’s figure of an ‘Osses ‘Ed, emphasising the resemblance to a miniature horse’s head with the apparent eyes, mane and ears clearly drawn.


Bassett, M.G. 1982. Formed stones, folklore and fossils. National Museum of Wales, Cardiff, 32 pp.

Boriskovskij, P I. 1963. Essays on the Paleolithic of the Don Basin (in Russian) Mater. Issled. Arkheol. SSSR, 121: 80-124.

Duffin, C. 2008. Fossils and folklore. Ethical Record 113: 17–21.

Duffin, C.J. & Davidson, J.P. 2011. Geology and the dark side. Proceedings of the Geologists’ Association 122: 7–15.

Evans, G.E. 1966. Patterns under the Plough. Aspects of the Folk-Life of East Anglia. Faber and Faber, London.

Glørstad, H., Nakrem, H.A. & Tørhaug, V. 2004. Nature in Society: Reflections over a Mesolithic Sculpture of a Fossilised Shell. Norwegian Archaeological Review 37: 95–110.

Hegele, A. 1997. Donnerkeil und Teufeflsfinger: Belemniten in Voldsglauben und Volksmedizin. Fossilien 1/97: 21–26.

Kennedy, C. B. 1976. A fossil for what ails you. The remarkable history of fossil medicine. Fossil Magazine 1: 42–57.

Knell, S. J. 1988. The Natural History of the Frodingham Ironstone. Scunthorpe Borough Museum and Art Gallery, Scunthorpe.

Martin, M. 1703. A Description of the Western Isles of Scotland. Andrew Bell, London.

Newberry, P. E. 1910. The Egyptian cult-object and the ‘thunderbolt.’ Annals of Archaeology and Anthropology 3: 50–52.

Oakley, K. P. 1974. Folklore of fossils. Part I. New York Paleontological Society Notes 5 (1-2): 9–17.

Plot, R. 1677. The Natural History of Oxfordshire: being an essay towards the Natural History of England. Oxford.

Fig. 8. ‘Bull’s heart’, the internal mould of the Jurassic bivalve, Protocardia, as illustrated by Robert Plot.

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