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Fossil type

Where to find crinoids

Crinoids — 'sea lilies' — are stalked echinoderms still living today, but at their Carboniferous peak they covered shallow sea floors in dense meadows. Their preserved stem segments are among the most common Carboniferous fossils. Mineral Wells Fossil Park (Texas) is the canonical North American site.

51 fossil sites

Frequently asked questions

What do crinoid fossils look like?
Complete crinoid fossils are uncommon. Most crinoid material you will find consists of isolated stem ossicles — the disc-shaped segments that made up the long stalk anchoring the animal to the seafloor. These range from 3 to 15 mm across and typically have a five-petalled star pattern on their faces and a central hole (the lumen) where the stalk nerves and water-vascular tissue ran. Ossicles are so common in Carboniferous limestone that they are sometimes called 'St Cuthbert's beads' in the UK. Complete crowns — the feeding arms and calyx (head) — are far rarer because they disarticulate rapidly after death. The best-preserved complete crinoids come from Carboniferous sites in Crawfordsville, Indiana, and from Jurassic limestone quarries in Germany.
Where can I find crinoid fossils?
Crinoid stem ossicles are among the most common fossils in any Carboniferous limestone. Mineral Wells Fossil Park in Palo Pinto County, Texas (Pennsylvanian, free) produces abundant crinoid stems alongside brachiopods and corals. Caesar Creek State Park in Ohio (Ordovician, Army Corps spillway) yields crinoid material alongside trilobites and brachiopods. In the UK, Carboniferous limestone exposures in the Peak District, the Mendips, and South Wales regularly produce crinoid ossicles. Complete or near-complete crinoid crowns, which require exceptional preservation, are commercial rarities sold by specialist fossil dealers — they are not realistic field finds at most accessible public sites.
Are crinoids extinct?
No — crinoids are still alive today. Approximately 600 living species exist, divided between stalked sea lilies (which anchor to the seafloor) and free-moving feather stars (comatulids). Living stalked crinoids were long thought to be restricted to deep water, but they have since been documented in shallow tropical settings in Papua New Guinea and other locations. The fossil record for crinoids extends from the Ordovician (approximately 480 Ma) to the present, with peak diversity in the Carboniferous when dense meadows of crinoids covered shallow sea floors globally. The end-Permian mass extinction severely reduced crinoid diversity, and the modern fauna represents a recovery from that event over the subsequent 250 million years.