Fossil fish (Gasterosteus doryssus or Nevada stickleback) in diatomite (a silica-rich rock composed of skeletal remains of diatoms, single-celled plants) from a Miocene freshwater lake, approximately 7 to 8 million years old, Hazen Pit, Churchill County, Nevada. Fossils of the Nevada killifish or top minnow (Fundulus nevadensis) are also common at this locality. Collectors must get permission from the owner, Eagle-Picher Minerals, Inc. (343-1818), to visit this mine.