Ammonites are easy to find on Whitby Beach, so fossil and curiosity dealers would try to attract customers by carving snake heads on the stones. It was a particularly tempting ploy in the Victorian age, when fossil collections and curiosity cabinets were all the rage.
The carvers were inspired by the legend of St Hilda, an abbess who lived in Whitby in the 7th century. The area was infested with snakes until she turned them all into “coils of stone”. Her work was completed by St Cuthbert of Lindesfarne, whose curse left the snakes headless.
Before fossils were understood, this provided a likely explanation for their proliferation in the area. The snakestones could be sold to the gullible as one of the few who escaped decapitation. The scientific name of one of the local ammonites is Hildoceras.
The Whitby snake stone in the photograph is on exhibition in the British Museum