Pantodonts, known also as _amblypods_, were primitive, hoofed, herbivorous animals. They were distinguished by a heavy skeleton, short stout limbs, and blunt spreading feet. The pantodonts appeared first during Paleocene time and had become extinct by the end of the Oligocene. Order Dinocerata.— The members of this order are an extinct group of gigantic mammals commonly called _uintatheres_. _Uintatherium_ (Pl. 48), which is typical of the group, had three pairs of blunt horns, and the males had dagger-like upper tusks. Some of the uintatheres were as large as a small elephant and stood as much as 7 feet tall at the shoulders. The size of the brain in relation to the size of the body suggests that these animals were not as intelligent as most mammals. Uintatheres are known from rocks ranging from Paleocene to Eocene in age. Uintathere remains have been reported from Big Bend National Park in Trans-Pecos Texas. Order Proboscidea.— The earliest proboscideans, the elephants and their relatives, first appeared in the late Eocene of Africa and were about the size of a small modern elephant but had larger heads and shorter trunks. Proboscidean development is marked by an increase in size, change in skull and tooth structure, and elongation of the trunk. Two well-known fossil proboscideans are the _mammoth_ and the _mastodon_, both of which inhabited Texas during Pleistocene time. The mastodons resembled the elephants, but the structure of their teeth was quite different (fig. 25). Moreover, the mastodon skull was lower than that of the elephant and the tusks were exceptionally large—some reaching a length of 9 feet. [Illustration: Plate 47 CENOZOIC MAMMALS] DINOBASTIS × ¹/₂₀ CANIS DIRUS × ¹/₁₅ HYRACOTHERIUM × ¹/₁₀ PLIOHIPPUS × ¹/₂₀ There were several types of mammoths, and the _woolly mammoth_ is probably the best known. This animal lived until the end of the Pleistocene and, like the woolly rhinoceros discussed below, is known from ancient cave paintings and frozen remains. Information gathered from these sources indicates that this great beast had a long coat of black hair with a woolly undercoat (Pl. 49). [Illustration: Fig. 25. Sketches of Pleistocene (a) mastodon tooth (×⅙) and (b) mammoth tooth (×⅙).] During the Pleistocene, mammoths were widespread over the United States, and their remains are abundant in many stream deposits of this age. Proboscidean bones have been reported from Pleistocene rocks in many parts of Texas, where they are commonly found in sand and gravel pits. Order Perissodactyla.—