Dinosaur geology: Sedimentary sequence at Ghost Ranch, New Mexico. Triassic Chinle Formation (red, foreground); Jurassic Entrada Formation (red/white cliffs); Jurassic Morrison Formation (slopes); Cretaceous Dakota Sandstone (upper cliffs). Aside for having been the residence of the artist Georgia O'Keeffe, Ghost Ranch, near Abiquiu, New Mexico, is also famous for the discovery of a mass mortality site of the dinosaur 'Coelophysis'. An expedition of the American Museum of Natural History led by Edwin Colbert found the site in 1947. Coelophysis was a small carnivorous dinosaur of the late Triassic.