Species: halli CAMP, 1936
Etymology: In honor of Ansel Franklin Hall, Chief of the Division of Education and Forestry, National Park Service, and General Director of the Rainbow Bridge-Monument Valley Expeditions of 1933-1934.

Holotype: UCMP 32101

Locality: UCMP locality V3308, about 1 mile north of Keet Seel Ruion on west side of Keet Seel Canyon, the north branch of Segi Canyon (=To' wan'-aho'che Creek), about 14 miles by trail northwest of Marsh Pass on the Kayenta-Tuba City road, at about 36°46'50"N, 110°31'30"E, Navajo Indian reservation, Arizona.

Horizon: Navajo Sandstone, approximately 154 m above its base.

Biostratigraphy:

Age: ?Sinemurian-Pliensbachian Stage, Lias Epoch, Early Jurassic.

Material: Shoulder girdle, two anterior dorsal vertebrae, anterior caudal vertebrae, left humerus, parts of left radius and ulna, ends of two digits of left foot, ribs on left side, parasternum, sacrum, pelvis, left hind limb and foot, and parts of right hind limb and foot.
Note: Furcula has been found with specimen.