Crinoid Limestone
“Stone built from sea lily stems”
Crinoid limestone is a variety of limestone packed with the fossilized stem segments (columnals) of crinoids — graceful marine animals also called sea lilies, related to starfish and sea urchins. Their disc-shaped stem pieces often resemble stacked coins or buttons scattered through the rock.
calcite (crinoid ossicles), calcite cement, micrite, brachiopod and bryozoan fragments (minor)
Peak District (England), Indiana (USA), Burlington (Iowa, USA), Gotland (Sweden), Mississippian limestones worldwide
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In medieval England, fossil crinoid stems were called 'St. Cuthbert's beads' and strung as rosaries — legend held they were made by the ghost of St. Cuthbert on Holy Island during his nightly vigils.
Test Your Knowledge
What medieval English legend explained the origin of fossil crinoid columnals?
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