Fossil group

Crinoid stem fragments

Echinoderms · Ordovician – Recent

Stalked, flower-like echinoderms ("sea lilies") that filter food with feathery arms atop a stem of stacked calcite discs. Their broken stem ossicles are so common they form whole Palaeozoic limestones; stalkless relatives (feather stars) live today.

A broad fossil group rather than a single taxon — the units below record it among their fauna or flora.