Within the Morrison Formation, "Ceratosaurus" fossils are frequently found in association with those of other large theropods, including the megalosaurid "Torvosaurus" and the allosaurid "Allosaurus". The Garden Park locality in Colorado contained, besides "Ceratosaurus", fossils attributed to "Allosaurus". The Dry Mesa Quarry in Colorado, as well as the Cleveland-Lloyd Quarry and the Dinosaur National Monument in Utah, feature, respectively, the remains of at least three large theropods: "Ceratosaurus", "Allosaurus", and "Torvosaurus". Likewise, Como Bluff and nearby localities in Wyoming contained remains of "Ceratosaurus", "Allosaurus", and at least one large megalosaurid. "Ceratosaurus" was a rare element of the theropod fauna; it is outnumbered by "Allosaurus" at an average rate of 7.5 to 1 in sites where they co-occur.