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the brown-coal deposits of Savoy. Leidy many years ago 

 <i escribed the first American species under the name Hyopotamus 

 americanas. This consisted of only a fragment of a jaw with 

 some teeth and until recent years little information of American 

 material has been available. Five species, all from the Oligo- 

 cene, are now recognized from the badland formations of the 

 Black Hills region. They are as follows : 

 Lower Oligocene. 



Hyopotamus {Ancodon) americanus Leidy 

 Middle Oligocene. 



Anthrac other ium cur turn Marsh 

 Hyopotamus {Ancodon) ro stratus Scott. 

 Upper Oligocene. 



Anthrac otherium karense Osborn and Wormian. 

 Hyopotamus {Ancodon) brachyrhynchus Osborn and 

 Wormian. 

 Of the two genera the Hyopotami are generally of lighter 

 build. For a restoration of Hyopotamus (Ancodon) brachyrh- 

 ynchus see Figure 15. For additional details of desccription the 



Figure 15 — Restored skeleton of Hyopotamus {Ancodo?i) brachyrhyn- 

 chus. After Scott, 1895. 



reader will find the following papers of value: Scott, W. B. 

 The Stucture and Relationships of Ancodus. Journ. Phila. 

 Acad. Nat, Sci., vol. 9, 1894, pp. 461-497 and p. 536. Osborn 

 H. F., and Wormian, J. L., Fossils of the Lower Miocene White 

 River Beds. Collection of 1S92. Bull. Am. Mus. Nat. Hist, 

 vol. 6., 1894, pp. 199-228. Family Anthracotheriidae pp. 219- 

 223. Matthew. W. D. Observations upon the Genus Ancodon. 

 Bull. Am. Mus. Nat. Hist., vol. 26, 1909, pp. 1-7. 



