OF WESTERN NORTH AMERICA. 



75 



As analyzed by Matthew'^ it is to be noted that: (1) The Rosebud 

 fauna contains no new immigrants, but is mainly a further develop- 

 ment of the John Day fauna; all the animals exhibit slightly or 

 decidedly more progressive stages. For example, the camels of the 

 Monroe Creek, Harrison, and Rosebud are decidedly more advanced 

 than anything from the upper part of the John Day, as are also the- 

 horses, carnivores, rodents, and oreodonts. (2) This fauna was dis- 

 tributed farther out in the Plains Region, a circumstance that may 

 have differentiated it locally from the more westerly fauna of the 

 Monroe Creek and Harrison formations, which was presumably near 

 the sources of the water supply, forests, etc. This fact of local dis- 

 tribution may account for some differences in comparison with the 

 Monroe Creek and Harrison lists above. These differences may be 

 reduced or increased by further exploration. 



A. LOWER PART OF ROSEBUD. 



Homotaxis. — 1, Lower part of Rosebud of Matthew; 2, Gering 

 of Darton, Hatcher, and Peterson; 3, Monroe Creek of Hatcher; 

 4, Harrison of Hatcher; 5, Middle portion of ' 'Martin Canyon 

 beds" of Matthew, Colorado. 



Fauna. ^ — Among Carnivora, Nothocyon, Mesocyon, Enhydrocyon, 

 Nimravus; among Rodentia, Entoptychus, Steneofiher, Euhapsis, 

 Meniscomys, Lepus; among Perissodactyla, Parahippus, lAnchi- 

 therium, Dicer atJierium; among Artiodactyla, Elotherium, Eporeodon, 

 Mesoreodon, Promerycoclmrus (very abundant and characteristic), 

 LeptaucJienia, and Hypertragulus. 



B. UPPER PART OP ROSEBUD. 



Homotaxis. — 1, Upper part of Rosebud of Matthew. 2, Deposits 

 near Laramie Peak, Wyoming. 3, Upper part of Harrison of Peter- 

 son, western Nebraska. 4, Summit of '^Martin Canyon beds" of 

 Matthew, Colorado. 



Fauna. — (1) Few species pass from the lower part of the Rosebud 

 into the upper part. (2) The Elotheriidse, Hypertragulidse, and 

 Pr ornery cocJioerus have probably disappeared. (3) The Diceratheriinae 

 continue. Among Carnivora, Vynodesmus, Megalictis, Oligohunis. 

 Among Insectivora, Arctoryctes (a supposed member of the Chryso- 

 chloridae). Among Rodentia-Geomyidse, Entoptychus, Lepus, and a 

 heteromyid. Among Perissodactyla, 2 families: Parahippus, other 

 Equidse, Dicer atherium. Among Artiodactyla, 4 families: (a) Dico- 

 tylidse, DesmatJiyus; (6) among Oreodontidse, Merychyus is ex- 

 tremely abundant and characteristic; Merycochoerus also appears 

 for the first time; (c) Camelidse, Protomeryx; (d) Cervidse, Blastomeryx. 



a A lower Miocene fauna from South Dakota: Bull. Am. Mus. Nat. Hist., vol. 23, 1907, pp. 169-219. 

 See Appendix, p. 91. 



