7.6" Multiple Blastoid (Pentremites) Plate - Illinois

Multiple Blastoid (Pentremites) Plate - Illinois #135621

This is a 7.6" wide plate with 17 Blastoid (Pentremites sp.) fossils collected from St. Clair County, Illinois. The fossils are Upper Mississipian in age or approximately 325 million years old. The blastoids have been cleaned using air abrasives. Most are in their natural position on the rock though some may have been remounted.

The rock also includes various bryozoan fossils, brachiopods and coral. It comes with an acrylic display stand.

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.

SPECIES

Pentremites sp.

AGE

Upper Mississipian (~325 Million Years)