An extinct order of large herbivorous mammals, often called uintatheres, from early Cenozoic deposits of North America and northern Asia. Members of this group have semigraviportal limbs, that is, adapted to bearing considerable weights, with hoofed, five-toed feet. The dentition is somewhat reduced in all forms, later ones losing all the upper incisors and in one case (Gobiatherium, from the late Eocene of Mongolia) even the upper canine. The cusps of the upper molars and premolars form V-shaped patterns. The lower molars and premolars possess V-shaped crests, followed by a low shelf. A saberlike canine tooth and protective lower jaw flange are present in all forms except the aberrant Gobiatherium, which must have relied on other means for defense. Horns are absent or very small on the most primitive forms, but by early Eocene time North American genera had begun to develop them. Middle and late Eocene uintatheres in North America developed an imposing array of six horns. One pair was on the tips of the nasal bones, another was above the root of the saberlike canine tooth, and a third pair above the ear region.