.27" Fossil Blastoid (Pentremoblastus) - Illinois

Fossil Blastoid (Pentremoblastus) - Illinois #216496

This is a .27" long, fossil blastoid (Pentremoblastus conicus) from the McCraney Limestone of Adams County, Illinois. The blastoid was meticulously prepped using air abrasives under stereo microscope and has been mounted back to the rock it was found in.

The specimen has been mounted to an acrylic display base.

Blastoids are an extinct type of filter feeding, stemmed echinoderm that resembles a small hickory nut. They thrived during the Mississippian period before going extinct during the great Permian extinction. While not as diverse as their crinoid relatives, they were equally as common in rocks around the world. Blastoids were protected by a set of interlocking plates that formed the main body, or theca. In life, a typical blastoid's theca was attached to a stalk or column made up of stacked disc-shaped plates.

About Crinoids