UC" 
H. F. OSBORN — MAMMALIAN PALÆONTOLOGY 103 
The chief geological result is the separation of the fluviatile or 
channel beds, with chiefly lowland or bottom fauna, from æolian or 
backwater sediments, chiefly with a plains and cursorial fauna. The three 
subdivisions originally observed by Haypex and Leiy are thus divided as 
follows : 
L Fluviatile or Channel Beds. II. Æolian or Backwater Sediments. 
Upper, Protoceras beds.......... Leptauchenia beds. 
Middle, Metamynodon beds....... Oreodon beds. 
Lower, Titanotherium beds. 
This separation was chiefly brought about by MarrHew’s careful ana- 
lysis of the animals coming from these respective beds, the former (1) in- 
cluding lowland, forest and river-bottom, and aquatic animals, the 
latter (I) the animals of the plains and uplands. The John Day beds of 
Oregon apparently contain an overlapping fauna partly equivalent to the 
Upper Oligocene and partly to the Lower Miocene. 
The already well known (Core, Fizxor,) and close zoogeographical rela- 
tionships during the Oligocene of North America and Europe are streng- 
thened by the discovery of European Anthracotheriidæ, Mustelidæ (Bu- 
nælurus') and Erinaceidæ (Proterix, Marrnew ?) in America, and of the 
American Titanotheriidæ in Europe*. This leaves as the chief families in 
Europe still unknown in America the Palæotheriidæ, Anoplotheriidæ, 
Tragulidæ. 
Our faunal knowledge has been especially enriched by the discovery and 
description of the hitherto unknown microfauna of the Titanotherium 
beds (Doucras, Marrnew ‘), which includes archaïc, Centetes-like forms, 
as well as Zrinaceus-like forms. 
The main phylogenetic results are the following. The Creodonta have 
been definitely traced to their extinction in the Hyænodontidæ (Table IT). 
Among the Canidæ the ancestral line of Cyon (Dnores) has almost cer- 
tainly been recognized in this period in the genus T'emnocyon (WorTMAN 
and Marraew*) (Fig. 6). No trace of Edentata has been found, the forms 
formerly described as such now being known to be the peculiar Chalico- 
? Marraew, W. D. On the Skull of Bunælurus. Bull. Amer. Mus. Nat. Hist., 
xvi, 1902, pp. 137-140. 
? A Fossil Hedgehog from the American Oligocene. Bull. Amer. Mus. Nat. Hist., 
Vol. xix, 1903, pp. 227-229. 
$ TouLa. Ueber neue Wirbelthierreste aus dem Tertiär Œsterreichs und Rumeliens. 
Zeïtschr. d. Deutsch. geolog. Ges., Jahrg. 1896, pp. 922-924. 
# Foss. Mamm. White River. Trans. Amer. Philos. Soc., n.s., Vol. xx, 1901, p. 1-42. 
® The F'auna of the Titanotherium beds. Bull. Amer. Mus. Nat. Hist., Vol. xix, 
1903, pp. 197-296. 
5 Bull. Amer. Mus. Nat. Hist. Vol. XII, 1899, pp. 139-148. 
