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).

Cambrian Trilobites of Utah

A Modocia typicalis trilobite fossil of the Cambrian Period (570-500 million years ago). Fossil was found in Utah.

Picture below of a Tricrepicephalus corri Cambrian Period trilobite fossil found in Utah.

Both fossils were on display at the Smithsonian National Museum of Natural History (August 2010).