This is a Gilbertsocrinus Crinoid Calyx from the Silica Shale of Ohio. This crinoid was collected years ago. All of the Sylvania quarries have been closed and off limits to collectors due to liability issues.
Here is a detailed calyx crown and stem from a classic site in Ohio. You can look down inside the calyx and the arms as well. But the arms have fallen apart.
The Gilbertsocrinus Crinoid Calyx from this site is preserved in spectacular detail. Because of the wide variety and number of these crinoids it is also believed they lived in large groups.
Crinoids look like plants and are also called “sea lilies,” but crinoids are actually animals related to modern day starfish. They have modern relatives living in the deep oceans today however then they lived in shallow salt water seas and lagoons. They lived during the Paleozoic and were most common during the Mississippian Period, which is sometimes known as the “Age of Crinoids.” This Gilbertsocrinus Crinoid Calyx is one of them.
Because there were many species of crinoids, they shared a basic body styles consisting of a stem by which it anchored to the sea floor with a “holdfast”. And they had a calyx or cup which enclosed soft body tissues, and arms and pinnules which filtered food from the water.
Crinoids thrived in the warm inland sea that covered the area during the Devonian Period some 380 million years ago. But crinoids living near what is now Sylvania were established near a delta system that periodically buried the colonies in silt. This silt eventually hardened into stone that preserved the Sylvania crinoids in glorious detail.
This Crinoid has exceptional detail that is evident becasue it has been meticulously prepared using air abrasive technology.
Silica Shale Formation