106 The Badland) Formations of the Black Hills Region 



Concerning all of the above forms, it may be said that they 

 with the Suidae were apparently derived from a common Eocene 

 ancestry. The Dicotyline group is first clearly distinguished 

 from the others in the Oligocene Perchoerus. According to 

 Matthew and Gidley the peccaries originated in the new world 

 and have always remained here, while the true pigs (suinae) 

 originated in the old w T orld and never of their own accord 

 reached the new world, their presence here now of the latter 

 being due solely to introduction by man since the discovery of 

 America by Columbus. 



LEPTOCHOERIDAE. 



Three species of Leptochoeridae are recorded from the 

 Middle Oligocene of the Black Hills region. Two are from the 

 Big Badlands and one from northwestern Nebraska. Leidy in 

 .1:856 described certain teeth which he designated as Leptoch- 

 cerus spectabilis and later additional teeth and a fragmentary 

 jaw were considered as referable to the same species. Marsh 

 in 1894 described another species Leptochoerus gracilis, his ma- 

 terial consisting of an adult skull and much of the skeleton in 

 fine state of preservation, the animal being "about as large as a 

 labbit." Still later Hatcher, 1901, described Stibarus quadri- 

 cuspis from fragmentary material. . Leidy in his early work 

 stated that the teeth indicate an animal of a somewhat suilline 

 nature and Marsh's studies on more complete material affirm 

 Leidy' s suggestion. 



ANTHRACOTHERIIDAE 



The Anthracotheriidae include species of an extinct family 

 of stoutly built, generalized, primitive animals, with teeth ap- 

 proaching the selenodont shape, and evidently resembling to 

 some extent the present day pig but having some characters 

 possessed by the hippopotamus. Their nearest important rela- 

 tives of the time were apparently the Oreodontidae. These they 

 resembled very closely. Scott states that the likeness as shown 

 in the skull, teeth, vertebrae, limbs, and feet, is fundamental 

 and indicates a common pentadactyl ancestry of perhaps middle 

 fiocene time. 



Fossils representing various species of the -family are 

 widely distributed over the earth, more particularly in the old 

 world. The name Anthracotherium (Coal-beast) arises from the 

 fact that their remains were first discovered in coal deposits, 



