This is an Arthroacantha Carpenteri Calyx from the Silica Shale of Ohio. These crinoids were collected decades ago. All of the Sylvania quarries have been closed and off limits to collectors due to liability issues.
Here is a Super detailed calyx crown from a classic site in Ohio. The anal tube is also present.
Fossils from this site are preserved in SPECTACULAR detail. Because of the wide variety and number of these crinoids it is also assumed they lived in dense communities.
Arthroacantha Carpenteri Calyx. They 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. These animals lived during the Paleozoic and were most prevalent during the Mississippian Period, which is sometimes known as the “Age of Crinoids.”
Although there were many species of crinoids, they shared a basic body styles consisting of a stem and a holdfast by which it held on to the sea floor. It had a body that enclosed soft body tissues, and arms 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. The 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. It has been meticulously prepared using air abrasive technology.
It comes in this 4 1/4 by 4 1/4 “Floating Frame” so it can easily be seen from all angles. The calyx itself in 1/2 inch
Silica Shale Formation