Clearance Lot: Illinois Blastoid Fossils on Shale - 24 Pieces

Clearance Lot: Illinois Blastoid Fossils on Shale - Pieces #215289

This is a wholesale lot of 24 Pentremites blastoid fossils. These blastoids are Upper Mississipian (Carboniferous) in age and were collected in St. Clair County, Illinois. They are all meticulously prepared using air abrasives to exposed them from the shale. Some of these specimens are completely free of shale or have been mounted back to the shale following prep.

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.