The Cirroceras nebrascense ammonite fossil displayed at the Carnegie Museum of Natural History in Pittsburgh, Pennsylvania (July 2011). This fossil was probably found in South Dakota. The creature swam the Western Interior seas of the Upper Cretaceous (Mesozoic Era). Its Carnegie museum accession number is CM 29908.
Visit the Carnegie museum web site: http://www.carnegiemnh.org/
View another specimen at the U.S. National Museum of Natural History: CLICK HERE