Fossil ammonites

From Yorkshire, England, Jurassic, 206 to 104 million years old

These two fossilized ammonites symbolize the change in thinking about fossils that occurred during the eighteenth century.

At the beginning of the century, fossils were described as 'figured stones', whose presence could be explained through legendary tales. According to one story, St Hilda, the Saxon Abbess of Whitby (614-680) had turned snakes into stones. A version of this tale in Marmion. A Tale of Flodden Field by Sir Walter Scott (1771-1832) tells of
'How of a thousand snakes each one
Was changed into a coil of stone
When holy Hilda prayed.'

Taking advantage of this story, curiosity dealers carved snakes' heads onto the fossils of ammonites, as can be seen on one of these specimens. These became known as Whitby 'snake stones'.

During the eighteenth century, however, natural philosophers began to speculate that fossils were in fact the remains of once living creatures. The presence of distinctive fossils such as ammonites in specific types of rock allowed geologists like William Smith (1769-1839) to recognize that rocks in different locations were of the same age. This was central to the development of Smith's theories of stratigraphy, based upon which he produced the world's first large-scale geological map.

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Fossil ammonites

© 2003 The Natural History Museum
Whitby 'snake stone'

  • Fossil ammonite

    Fossil ammonite


More information


K. Sloan (ed.), Enlightenment. Discovering the (London, The British Museum Press, 2003)

Simon Winchester, The Map that Changed the World (Penguin Books, 2002)

W.N. Edwards, Early History of Palaeontology (London, British Museum (Natural History), 1967)


Diameter: 6.500 cm
Height: 1.500 cm
Diameter: 6.500 cm
Height: 1.500 cm

Museum number

On loan from the Natural History Museum C727;On loan from the Natural History Museum C723/37927


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