Stegosaurus, the state fossil of Colorado, was a strange looking herbivore with an array of distinctive plates along its back and spikes on its tail. Its name, which means “roof lizard,” comes from an early theory that Stegosaurus’s plates laid flat on its back, overlapping each other like shingles on a roof. Today, most paleontologists think of Stegosaurus’s plates as sticking straight up out of the back in two alternating rows. The discovery of the world’s most complete Stegosaurus in 1992 supported this theory, as its plates appear to be in two alternating rows.
As with Camptosaurus, Apatosaurus, and Allosaurus material in this location, the Stegosaurus fossils in the Cope-Lucas Quarries were originally given different names. Bones from what Cope called “Hypsirhophus discurus” and “H. seeleyanus” were probably remains of Stegosaurus. The previously mentioned 1992 Stegosaurus, also found in Garden Park, is a specimen of S. stenops, which in life would have been about 23 feet long (7 meters). (Carpenter, 1998)
This image, created by Matt Martyniuk, shows Stegosaurus stenops, the type species identified by Marsh in 1887, and S. ungulatus, also named by Marsh in 1879.
Dinosaur Depot's website has more information about the incredible discovery of the world's most complete Stegosaurus.
Carpenter, K., 1998, Armor of Stegosaurus stenops, and the taphonomic history of a new specimen from Garden Park Colorado in The Upper Jurassic Morrison Formation: An Interdisciplinary Study, Part 1: Modern Geology, no. 22. p. 127–144.