June 19. Crinoids

Actinocrinites gibsoni, Montgomery Co., Indiana

Crinoids really thrived in the warm shallow Mississippian carbonate seas of central North America. At Crawfordsville, Indiana, there’s a lagerstatten – an assemblage of fossils that is remarkable in the completeness and preservation of the fossils. It has lots of crinoids, with the fine details of their arms and other structures remarkably well preserved. They lived about 340 million years ago, a time called the “Age of Crinoids,” at least in Indiana and much of the rest of the region covered by those seas. Crawfordsville crinoids are found in museums of paleontology around the world.  

A picture is worth a thousand words - check the links below. 

—Richard I. Gibson

Photo galleries:
Virtual Fossil Museum 

Indiana Fossils website