Triassic microvertebrate locality, Chinle Formation, east-central New Mexico
— Spencer G. Lucas, Wayne Oakes, and Jeffery W. Froehlich

Fossil vertebrates from the Upper Triassic strata of east-central New Mexico have been known for nearly a century. One of the longest known Triassic vertebrate collecting areas in east-central New Mexico is Bull Canyon (Fig. 1) where more than 85 m of fossiliferous strata of the upper shale member of the Chinle Formation are exposed (Lucas et al., 1984). First mentioned as a Triassic vertebrate collecting area by Case (1914), Bull Canyon has produced the holotype skull of the phytosaur  Machaeroprosopus (=Rutiodon) andersoni Mehl, 1922, and the remains of fishes, amphibians ("Buettneria") and other phytosaurs (Gregory, 1972). Since 1983, field parties from the University of New Mexico (UNM) have amassed an extensive collection of vertebrate, invertebrate and plant fossils from the upper shale member of the Chinle in Bull Canyon. This paper describes in a preliminary way the vertebrate fossils from one UNM microvertebrate locality in Bull Canyon.