Crinoid fossils are most commonly found in limestone deposits that were once ancient seabeds. These fossils often consist of the stalk or column, the most durable part of the crinoid’s anatomy.

Limestone consists mainly of calcium carbonate ... like tentacles extend out and filter food particles from the water. Multiple cross-sections of crinoid stems, also known as "Indian beads," are ...

discovered a limestone containing fragmentary organic remains. The fossils were thought to be nummulites, but afterwards they were shown to be crinoid ossicles of uncertain age. Fifty years later ...