Dizygocrinus montgomeryensis

Dizygocrinus montgomeryensis crinoid fossil found in Iowa.  This creatured lived in the Carboniferous Period (345-280 million years ago).  Fossil displayed at the Smithsonian Museum of Natural History (August 2010).

Halysites catenulatus

Halysites catenulatus of the Silurian Period found in Kentucky.  Fossil displayed at Smithsonian Museum on Natural History (August 2010).  My guess is this fossil was found in the Louisville Limestone.  Every museum with a Paleozoic fossil exhibit should have a piece of chain coral on display to represent the Silurian Period (in my opinion).

Phacops rana of Ohio

Phacops rana (Green, 1832) trilobite fossil found in Ohio.  Animal existed during the Devonian Period.  Fossil on display at Smithsonian Museum of Natural History (August 2010).

Genus named by Emmrich in 1839. The fossil genus has been renamed to Eldredgeops (Struve, 1990).