Snakestone specimen in the Cockburn

Dactilyoceras commune is a Lower Jurassic ammonoid often found in the sea cliffs of the Yorkshire Coast. Around Whitby they are common enough to feature on the coat of arms of the town in triplicate. However, these ammonoids have heads and the forked tongues of snakes, not what you expect of a cephalopod! This reflects a much older tradition in the town, whereby some Jurassic ammonoids have been altered into chimeras of mollusc and snake by craftspeople, often with incredible skill and flair. The Cockburn Museum is fortunate to have a particularly fine example in its collection, which enthused me enough to write a short post about this particular specimen.

Snakestone with scale bar and box

Oblique photograph showing the use of the septum to form the mouth and snout

Throughout medieval Europe, ammonoid fossils were regarded as the petrified remains of snakes . Even today palaeontologists use the terms serpentiform or serpenticonic to describe spiral ammonoid shell forms that resemble a Catherine wheel firework. St Hilda, or Hild, a 7th century Saxon princess who became the founding abbess of Whitby, is the saint most commonly associated with the myth of a devout Christian turning a plague of snakes to stone. Hilda was commemorated in the name given to another Jurassic ammonoid genus by Alpheus Hyatt, a 19th century ammonoid worker; Hildoceras is named after Hild.

Unsurprisingly, ammonoid fossils lack the head of a viper. This inconvenient point was explained away by further cursing from another saint with connections to northern England; St. Cuthbert. Cuthbert has his own associations with the natural world that are considerably less fantastical. Eider ducks are known as ‘Cuddy ducks’, due to claims that Cuthbert tamed the ones on the Farne Islands. Crinoid ossicles, which are plentiful in the Carboniferous rocks of northern England, are known as St. Cuthbert’s beads and were fashioned into rosaries. Both of these tales seem to appear in the 12th century AD and the beads became more popular when a limestone quarry opened in the 14th century and helped to supply the pilgrims with mementoes of their journey.

An example of crinoid (sea lily) ossicles strung to make a bracelet. From a collection donated to University of Glasgow

A similar opportunity seems to have arisen in Victorian times as Whitby became a popular destination as the railways opened up the possibility of mass tourism. Although earlier examples of ammonoids with snake heads carved on them are known from the 16th and 17th centuries, the artisan production of snakestones peaked during the Victorian era. Some examples of snakestones are executed in quite a rudimentary fashion but the example in the Cockburn Museum is more elaborate. One of the fluted and vaulted septa, the internal divisions of the shell that anticipate the interior of a Gothic cathedral, has been used to form the mouth and snout of the ‘snake’.

Artists continue to draw on the wave-swept rocks and the ammonoid fossil motif to produce contemporary artworks that provide a living link to the tradition. This JustBod Blog article about an inspirational visit to Whitby gives some insight the relationship between landscape, fossils and art.

About Al McGowan

I am a palaeobiologist in my early 40's carrying out research work. I am based in Scotland.