Fossil monoplacophorans displayed at the Smithsonian Museum of Natural History in Washington D.C.  These fossils are from the Cambrian Pe...

The fish fossil Priscacara clivosa found in Wyoming (probably Green River Formation).  It lived in the Early Eocene (50 million years ag...

This crinoid calyx with a long stem piece attached is the Forbesiocrinus multibrachiatus .  Existing in the early Mississippian Period (34...