The Stegosaurus was designated as the official state fossil on April 28, 1982 by executive order of Governor Richard D. Lamm. The Stegosaurus lived in the area we now know as Colorado one hundred and fifty million years ago during the Mesozoic era in the Jurassic period. It is believed that a typical Stegosaurus weighed ten tons though its brain weighed only two and one-half ounces. There are only 6 skeletons of the Stegosaurus on public display in the United States, one of which may be viewed at the Museum of Natural History in Denver. This skeleton was discovered by a teacher and students from Canon City High School.