Incredible Plate of St. Louis Urchins - Two Types!

Name: Archaeocidaris wortheni, Archaeocidaris illinoisensis
Age:  Mississippian
Formation:  St. Louis Formation
Location:  St. Louis, Missouri
Size: Plate is over 15 inches across!

Specimen SSA808

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This is simply an incredible fossil. It is an amazing plate with TWO HUGE Archaeocidaris wortheni and at least THIRTEEN 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. These spiny urchins are larger than the Lepidocidaris found in the Mississippian Warsaw Formation, and are OLDER than the Pennsylvanian Archaeocidaris from Texas. The two large, extremely rare Archaeocidaris wortheni urchins are complete with MANY long spines still intact. The huge echinoids display well on the hugee, semi-rectangular plate of matrix that also has THIRTEEN(!) fabulous examples of the smaller Archaeocidaris illinoisensis. This is a very special and extremely collectible fossil, a unique multiple example of two ultra-rare species of Archaeocidaris from the St. Louis Formation.


A Certificate of Authenticity from EXTINCTIONS is included with this specimen.

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