These are two fossil crinoids (Aorocrinus parvus and Dichocrinus multiplex) from the Gilmore City Formation of Gilmore City, Iowa. They are .7" (Aorocrinus parvus) and .55" (Dichocrinus multiplex) respectively and show a small portion of the stem, calyx (body) and pinnules (feeding arms) of both individuals. The rock has been meticulously removed using air abrasives to reveal the beautiful structure of this crinoid.
Crinoids, sometimes commonly referred to as sea lilies, are animals, not plants. They are echinoderms related to starfish, sea urchins, and brittle stars. Many crinoid traits are like other members of their phylum; such traits include tube feet, radial symmetry, a water vascular system, and appendages in multiples of five (pentameral). They first appeared in the Ordovician (488 million years ago) and some species are still alive today.