Name:
Archaeocidaris illinoisensis Age: Mississippian Formation: St. Louis Formation Location: St. Louis, Missouri Size: Urchin is about 2 inches across This specimen is not for sale Click here for similar specimens that are for sale
This is an excellent fossil echinoid. It is a fabulous Archaeocidaris illinoisensis from the Mississippian of St. Louis. Fossil echinoids from the St. Louis area are famous around the world and have been extremely sought-after by collectors for decades. This spiny urchin is larger than the Lepidocidaris found in the Mississippian Warsaw Formation, and are OLDER than the Pennsylvanian Archaeocidaris from Texas. This urchin is complete with MANY barbed spines still intact. Most of the types of urchins from this site have smooth spines (there are three species!), and ones with the barbed spines are collectible. The echinoid displays beautifully on the natural plate of matrix. This is a very fine example of a spiny Mississippian echinoid from the St. Louis Formation.