Crinoids are an extremely important group in the fossil record. Stalked sea-lilies formerly inhabited shallow seas in great abundance, the calcareous segments of their bodies sometimes present in sufficient numbers to build limestones, as in the Carboniferous of Britain.
The disc-shaped columnals that make up the stem are particularly numerous. Given their abundance and characteristic shape, it is not surprising that these fossils have folklore connections. Circular crinoid columnals are called St. Cuthbert's Beads or Fairy Money in some parts of Britain, while pentagonal columnals are known as star stones.