Isotelus maximus Trilobite Fossil

These trilobite fossils are called Isotelus maximus.  The fossil dates to the late Ordovician Period. It is Ohio's state fossil. It was found in the Cincinnatian Series of Cincinnati, Ohio, USA. The genus Isotelus was named by Dekay in 1824.

On display at Cincinnati Museum Center as of August 2013. The enrolled specimen (below) is labeled with accession number IP70253.

Below is a drawing of what the bottom of this creature looked like by Dr. Elvira Wood in 1920.

Source:

https://www.gutenberg.org/files/41695/41695-h/41695-h.htm