There are several kinds of fossil sea-urchin that are the subject of folklore, the commonest in the south of England being casts in flint, derived from the Chalk, of the heart-urchin Micraster, and of the helmet-urchin Echinocorys. Both of these, but more commonly the latter, are known to the country people as shepherd's crowns or fairy loaves (PL. xxib). Formerly at least, the Essex labourer believed that so long as one of these fossil sea-urchins was kept in the house, his family would never go short of bread (Johnson 1908, 149). At a number of localities in southern England fossil echinoids are traditionally placed on dairy shelves to keep milk from going sour. This practice is clearly linked with the ancient idea that these fossils are thunderstones.
The earliest known case of fossil echinoids being used in a ceremonial burial is in the Early Bronze Age tumulus on the Dunstable Downs, where nearly IOO shepherd’s crowns, mainly Micraster, had been arranged to encircle the bodies of a woman and child (Worthington Smith 1894, frontispiece, 337-8). H. S. Toms collected evidence that up to the middle of the last century fossil sea-urchins were called thunderstones throughout Sussex, whereas they are now simply regarded as ‘lucky’ (PL. XXIIb), and if seen in the soil and not brought home, at least one should spit on the shepherd’s crown and throw it over the left shoulder. Even the idea of luck being attached to sea-urchins found on the fields has disappeared latterly from many villages. As there were still scattered traces of the thunderstone belief in Sussex in 1930, it is probable that more than a century ago the thunderstone aspect was dominant there. This idea survived longer in West Sussex than in East Sussex, and oral tradition can be traced back to 1860.