76 The Badland Formations of the Black Hills Region 



ally plantigrade (walking upon the sole of the foot), the snout 

 is often prolonged into a short proboscis, and their chief food 

 is insects. The Carnivores include animals whose chief food 

 is flesh. They may be terrestrial, arboreal, or aquatic. They 

 have a simple stomach, a well developed brain, toes provided 

 usually with long, sharp claws, and generally they have a body 

 capable of much agility in the capture of prey. They walk 

 either upon the entire sole of the foot or upon the under surface 

 of the toes but never upon the tips of the toes as do the Ungu- 

 lata. The carnivorous structure is common to all of the class 

 but the carnivorous habit, though general is not universal. 

 Laving representatives vary in size from the little active ermine 

 to the powerful grizzly bear. The Rodents include a group 

 xf small to moderately large animals the most prominent 

 and universal character of which is their dentition. Canine 

 teeth are absent. The deeply set incisors, separated by 

 a considerable vacant interval from the molars, are long and 

 flat edged and are of paramount importance. Since they 

 lengthen by persistent growth they serve admirably for vigorous 

 chisel-like cutting of hard materials, hence the name "gnawers". 

 The animals are usually plantigrade, often burrowing not in- 

 frequently arboreal, and occasionally aquatic. They are today 

 represented by the squirrels, prairie-dogs, rabbits, rats, mice, 

 beavers, porcupines, and a host of others. The Ungulates (Her- 

 bivores) are plant- feeding animals with hoofs rather than claws 

 or nails, and with limbs perfected for running and not for climb- 

 ing and grasping. Viewed from the point of usefulness to man 

 they are the most important of all animals in that they furnish 

 him with food, clothing and working assistance. 



CARNIVORA. 



The Carnivora may be conveniently divided into three sub- 

 divisions (sub-orders) namely, tthe Creodonta, the Fissipedia, 

 and Pinnipedia. Of these the Creodonts, primitive carnivores, 

 are found only in the fossil state; the Fissipedes include our 

 common carnivorous animals, true carnivores, and are both 

 fossil and living. The Pinnipedes include the aberrant water- 

 loving animals, the seals and walruses. The Creodonts are 

 represented in our badland formation by but one family, the 

 Hyaenodonts. The Fissipedes have many important represen- 

 tatives. The Pinnipedes are not represented hence need no 

 further comments in this paper. 



