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The fossilised remains of ammonites were given the name snakestones in England because they resemble coiled snakes turned to stone. The myth about snakestones came mainly from two places where ammonites are very common and easy to find: Whitby in Yorkshire and Keynsham in Somerset

William Camden, an early cartographer (map maker)  mentioned what we now call ammonites in his 1586 book Britannia,’If you break them you find within stony serpents, wreathed up in circles, but eternally without heads.’ 

During the Victorian era some collectors and dealers played on this legend by carving snake heads on ammonite fossils and selling them for a premium.

Saint Hilda’s spell

Whitby has a strong link with fossils especially ammonites and jet. This link extends back to the 7th CE and the story of the Saxon Abbess, Saint Hilda (614-680). The legend states that St Hilda was ordered to build an Abbey in Whitby. However, the ground was infested with snakes. In the early Christian times, preaching always referred to snakes as being of the Devil (e.g. Adam and Eve and the apple). Naturally, before the Abbey could be built the ground had be cleared and sanctified.

Oddly for a Saint she cast a spell (not a prayer!) that turned all the snakes to stone and she threw them off the cliff tops.

St hilda monument
St Hilda with snakes at her feet

Named in honour of St Hilda, Hildoceras bifrons is one of the most common ammonites present at Whitby. This example has a carved snake’s head.

St Hilda’s miraculous work was immortalised in the poem Marmion, by Sir Walter Scott:

When Whitby’s nuns exalting told,
Of thousand snakes, each one
Was changed into a coil of stone,
When Holy Hilda pray’d:
Themselves, without their holy ground,
Their stony folds had often found.

St Cuthbert’s Curse

Whitby’s snakestones sometimes involve St Cuthbert who was a monk in the 7th century CE. Allegedly his rosary was made of fossil crinoids (St Cuthbert’s beads).
St Cuthbert curse is an alternative to St Hilda as ‘He is said to have cast a powerful beheading curse on all of the snakes.’

St Keyna’s prayers and fossil fairies

According to legend, Saint Ceyna (Keyne) one of the daughters of King Brychan of Brycheiniog (Brecon) having decided to become the equivalent of a modern nun and live the life of celibacy, she wanted to find a deserted place to follow her lifestyle and dedicate her time her religion. She travelled across the Severn to a wooded place and asked the local Prince for permission to stay and practice her religion. The Prince gave her permission but warned her that the area was so infested with snakes that nothing could life there. She said that with her beliefs it would be resolved and lay down dedicating the ground to the Holy Virgin. The serpents and vipers were then turned into stones. The place mentioned is Camden, near Keynsham, Bristol .

Horns of Ammon

The Ancient Greeks saw ammonites as sacred symbols associated with their horned god, Jupiter Ammon. They called them Cornu Ammonis (horns of Ammon). This is naturally the stem of the name “ammonite”
They believed Ammonites provided protection from snakebites and cures for blindness, barrenness and impotence.

The Ancient Romans believed that sleeping with a golden (pyritised) ammonite from Ethiopia under their pillow could help the dreamer predict the future.

Vishnu’s chakra

In Hindu culture, black limestone containing ammonites are known as saligrams (or shaligrams or salagramas) and considered extremely precious for their resemblance to the disc (chakra) held by the god Vishnu.

The stones are kept in temples, monasteries and households as natural symbols of the god Vishnu and are used during marriages, funerals and housewarmings.

Vishnu’s chakra is a Hindu symbol of absolute completeness. The eight spokes are believed to represent the eightfold path of deliverance. The radial chakra markings in saligrams are formed by the ribs of the ammonites.

Saligrams are mentioned in Sanskrit texts dating back to just over 2,200 years ago. Some Sanskrit poetical works identify them as fossils created by a kind of worm. True saligrams are found only in the valley of the Gandaki River in Nepal and northern India. Typically spherical, they contain black-coloured ammonite fossils from the Jurassic and Cretaceous periods. Light coloured, broken or sharp specimens are regarded as unlucky.

Horn Stones

In Chinese folklore, ammonites were called Jiaoshih or horn stones, as they resemble coiled rams’ horns. Eleventh-century Chinese scientist and stateman Su Sung wrote in Pen Tshao Thu Ching:
‘The stone-serpent appears in rocks which are found beside the rivers flowing into the southern seas. Its shape is like a coiled snake with no head or tail-tip. Inside it is empty. Its colour is reddish-purple. The best ones are those which coil to the left. It also looks like the spiral shell of a conch. We do not know what animal it was which was thus changed into stone.’

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Ammonites are perhaps the most widely known fossil, possessing the typically ribbed spiral-form shell.

These creatures lived in the seas between 240 – 65 million years ago, when along with the dinosaurs they became extinct.

Ammonites take their name from the Egyptian god Amun, known to the Greeks as Zeus Ammon known for having curved horns like a ram.

Ammonites are cephalopods. The group Cephalopoda is divided into three subgroups: coleoids (including squids, octopuses and cuttlefishes), nautiloids (the nautiluses) and ammonites. Ammonites’ shells make the animals look most like nautiluses, but they are more closely related to coleoids.

Ammonites were not always curved they were small, straight shelled creature, known as Bacrites. They quickly evolved into a variety of shapes and sizes including some shaped like hairpins or paper clips. Ammonites quickly assumed a strong protective outer shell to shield their soft interior from damage and predators. Some genera of ammonites had shells that were coiled in more bizarre ways than the usual spiral. These are known as heteromorphs, from the Greek heteros meaning ‘different’ and morphe meaning ‘form or shape’.  One of the most unusual is the Nipponites mirabilis which is U shaped like a “slinky”.

The closest living lookalike to the ammonite is the Nautilus. Both have a similar structure with a solid shell comprised of many chambers in a spial. The body of the ammonite was contained within the large final, open-ended section called the living or head chamber. As they grew, they built new chambers onto it. They would move their entire body into a new chamber and seal off their old and too small living space with walls known as septa.

New chambers were added at a rate of one every four weeks, roughly 13 each year. Using this as a guide we can tell approximately how old an ammonite is by looking inside its shell. A shell containing 26 chambers could be assumed to have housed the creature for two years. Ammonites kept their original shell for all their life.

The chambered interior of the shell is referred to as the phragmocone. This contained gasses which enabled the ammonite to regulate its buoyancy allowing it to rise and fall in the sea much like a submarine.

Each complete 360° coil is called a whorl. Except for the innermost whorl, the shell is made up of three layers. The thin innermost and outermost layers are composed of prisms of aragonite (a form of calcium carbonate). The thicker middle layer is nacreous (mother-of-pearl), formed of tiny tabular crystals of aragonite

Some ammonite fossils bear intricate patterned details on their outer surface called Sutures. These patterns mark where the walls of the chambers, Septum, meet the outer wall of the ammonite shell. Suture patterns are extremely useful for distinguishing distinct species of ammonite. It is estimated that over 10,000 to 20,000 species of ammonite have been discovered.

Ammonites vary enormously in size the Nannocardioceras is small with complete adults rarely more than 20 mm in diameter. However, a part fossil of a Parapuzosia seppenradensis (Late Cretaceous) was discovered which has a diameter of 1.95 m in. If complete, it would have had a diameter of about 2.55 m. .Evidence suggests that they rapidly gained in size, especially females which grew 400% bigger than the males.

Whilst they look quite harmless, ammonites were predators feeding eating molluscs, fish and even other cephalopods. They stalked their prey, then once close enough rapidly extending their eight arms to grasp their prey. Ammonites have powerful jaws located at the base of the tentacles between the eyes these could crack other creature’s shells before eating the meat inside. Ammonites may have supplemented their diet with small plankton or vegetation growing on the sea floor. Ammonites were also prey, there is evidence of mosasaurs and ichthyosaurs having eaten them.

Early historians and naturalists compared the coiled shape of the ammonite to that of a snake and ammonites became widely known as snakestones. To cash in on the legend, many collectors and dealers in fossils frequently carved heads on ammonites. The coat-of-arms of Whitby in North Yorkshire, includes three ‘snakestones.’

Ammonites were thought to be a protection against serpents and a cure for baldness and infertility.