Multiple Blastoid (Pentremites) Plate - Illinois

 
This is a plate with multiple Blastoid fossils collected from St. Clair County, Illinois. The fossils are Upper Mississipian in age or approximately 325 million years old. The blastoid fossils have been cleaned using air abrasives and remounted on a slab of matrix from the locality to create a beautiful display.

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 relative the crinoid, they were equally as common in rocks around the world. Blastoids were protected by a set of interlocking plates, which formed the main body, or theca. In life, the theca of a typical blastoid was attached to a stalk or column made up of stacked disc-shaped plates.
DETAILS
SPECIES
Pentremites
LOCATION
St. Clair County, Illinois
FORMATION
Ridenhower Formation
SIZE
Blastoids .75" Long, Plate 3" wide
CATEGORY
SUB CATEGORY
ITEM
#68961
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