54 



CEXOZOIC MAMMAL HORIZONS 



rMnussLiid Manteoceras indicate equivalence to upper Bridger (C-D). 

 (B) Eohasileus zone. Gray and green beds (250 feet), Haystack 

 Mountain, containing Eohasileus^ (LoxohpJiodon) ; Perissodactyla- 

 Ajnynodontidae : Titanotheriidae, Dolichorhinus comutus; Artiodac- 

 tyla-Elotheriidae. 



The lower (A) bro^^ii beds are very extensively distributed and con- 

 tain many of the same species as the upper Bridger (C-D). The 

 upper (B) gray and green beds, probably composed largely of volcanic 

 ash. are chiefly restricted to the great butte kno\\Ti as Haystack 

 Mountain and its outlying badlands; the fauna is largely new and 

 marks a very distinct progressive stage. 



Uie new fauna of the Eohasileus zone. — The archaic fauna is distin- 

 guished by the final evolution of the Ungulata-Amblypoda into large, 

 specialized Dinocerata. Carnivora-Creodonta certainly include Oxy- 

 jenidae and Mesonycliid^e : the Hyaenodontidfe are represented by 

 Si no pa. 



In regard to the modern fauna the most signal fact is the first 

 appearance among the Perissodactyla-Rhinocerotoidea of the new 

 family (a) Amynodontidae. The (h) H}Tacodontidie continue from the 

 Bridger: among {c)TitsLiiotheTudee,Pal^osyops disappears; (d) Lophio- 

 dontidae-Helaletinae, {e) Tapiridae, and (/'> Equida? persist. Artiodac- 

 tyla are small but more diversified. Rodent ia-Isch^Tom^-id^e. Pro- 

 Carnivora-Miacidae. Large elotheres, AcTisenodon, occur. 



UPPER EOCENE ^EUROPE, ETAGES BARTOXIEX IX PART, LUDIEX 



(LIGURIEX) IX PART . 



7. LATER EOCENE DEPOSITS OF THNTA BASIN: TTINTATHERITrM. EOBASILETJS, AND 



DIPLACODON ZONES. 



(Figs. 1. 2. 8: PI. I. I 

 HOMOTAXIS. 



XortJi America. — 1, Lower 800 feet, UintutJi^rium zone, provision- 

 ally equivalent to upper part of the Bridger formation and equivalent 

 beds in Washakie Basin. 2, Middle 350 feet, Eohasileus zone, equiva- 

 lent to upper zone of Washakie Basin. 3, Tapper 600 feet, Dij^lacodon 

 zone; equals L'inta formation ("true L^inta"),** approaching if not 

 equivalent to the lowermost levels of the White River Ohgocene, i. e., 

 lower TitanotJierium zone or Chadron formation. 



Europe. — Homotaxis is now very difficult owing to the absolute 

 dissunilarity of the European and Xorth American faunae in these 



a The name Loxolophodon. commonly applied by Cope and others to the Dinooerat-a of this stage, is 

 preoccupied for a Wasatch coryphodont. Loxolophodon semicinciu-'i Cope. Tinoceras Marsh is equally 

 inapplicable because first applied to a Bridger uintathere. 



b The Uinta formation as first noticed by Marsh (Introduction and succession of vertebrate life in 

 America: Am. Jour. Sci., 3d ser., vol. 14. 1877, p. 337) included only the highest Eocene deposits, 

 Dipl'irodon zone (horizon C, the '•true or upper Uinta" of King and other writers), to which Ijeds 

 the name is here restricted. 



