Most of the states in the United States of America have an official state fossil. Usually, the state fossil is one best known (or only known) from that state. State fossils range from petrified wood of a conifer tree (Arizona) to a trilobite (Pennsylvania), sea scorpion (New York) to mammoth (Washington). Designated by State Legislatures, most of the state fossils were legislated during the 1980s.
During the early 1980s, as part of the effort to build a natural history museum in New Mexico, museum supporters campaigned to have the New Mexico State Legislature designate an official state fossil to add to the other state emblems, which then included an official state flower (yucca), state animal (black bear), state bird (roadrunner) and others. The Triassic dinosaur Coelophysis is world famous because thousands of skeletons of this early dinosaur were found in a fossil bone bed at Ghost Ranch in Rio Arriba County, New Mexico. Known only from New Mexico, Coelophysis is a uniquely New Mexican dinosaur. On March 17, 1981, the New Mexico State Legislature designated Coelophysis as the Official State Fossil of New Mexico.