 In 1877, a number of fossils were discovered by Oramel William Lucas in rock outcrops in Colorado close to Canyon City.These bones, including some named "Laelaps trihedrodon", "Camarasaurus supremus" and "Caulodon", were assumed to be from the Cretaceous Dakota Formation by paleontologist Edward Drinker Cope, from the same age as other "Laelaps" fossils.Among the assortment of fossils discovered, a specimen including multiple dorsal vertebrae, a pubis, and a femur was found by Aaron Ripley, Lucas' brother-in-law, in Quarry XII.