One hundred and twenty eight million years ago, a killer stalked eastern Utah. Known as Utahraptor, this distant relative of Velociraptor of Jurassic Park fame was also equipped with a sickle-claw on its hind feet. The name means “Utah’s raptor” with “raptor” being the informal name commonly (but incorrectly) used for the sickle-clawed dromaeosaurid theropods. Utahraptor was named in 1993 by Dr James Kirkland for bones from the Gaston Quarry (also known as Yellow Cat Quarry), north of Arches National Park. The Gaston Quarry occurs in the lower part of the Yellow Cat Member of the Cedar Mountain Formation. The presence of an ankylosaur related to Polacanthus at the Gaston Quarry suggests that the Yellow Cat Member is the same age as the Wealden Formation on the Isle of Wight, in other words, it lived 125 to 130mya. A radiometric date of 126 +2.5mya was obtained from the Yellow Cat Member which supports the dinosaur evidence for the age. Utahraptor has been found at several other sites in the Yellow Cat Member, so must have been relatively widespread in the region. Nevertheless, most of this material remains undescribed.