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Devil's toenails (fossil oysters), Oxford University Museum of Natural History

The fossils are Gryphaea arcuata from the Lower Lias at Broadford, Skye. They are known colloquially as devil's toenails. They were put out as a temporary exhibit for a visit by a group from a conference "A history of geology and medicine" run by the History of Geology Group at the Geological Society in London.

In Scotland, fossil Gryphaea shells are known 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. (Information from Natural History Museum Link ).