92 



TITANOTHERES OF ANCIENT WYOMING, DAKOTA, AND NEBRASKA 



discovered 150 fossil mammals in the lower series, I by the subsequent explorations and publications of 

 which were first correlated by Osborn (1895.98, p. 72) 1 Douglass (1909.1) and Eiggs (1912.1). The strati- 



N. 



Mesatirhirvus superior, type 

 Metarhinus ripartus , •■ 



r Sthenodectes 



Anvynodon.CF>inte^-medzzts A 



Figure 64. — Section of the Uinta formation (No. 10, fig. 35) from Kennedy's Basin to White River 



Canyon, Utah 



This section includes Uinta A, the barren sandstones; Uinta B 1, the Metarhinus zone capped by prominent bluffs of "Metarhinus sand- 

 stone"; above this Uinta B 2, the Eobasileus-Dolichorhinus zone, capped by the "Amynodon sandstone." After E. S. Eiggs (1912.1); see 

 also F- B. Weeks (1907.1). 



with the typical "upper Washakie," now known as 

 Washakie B. The determination of the stratigraphy 

 as well as the faunistic succession has been modified 



graphic order of the later Eocene deposits of the Uinta 

 Basin and the correlated fauna may be presented as 

 follows : 



Later Eocene deposits and fauna in the Uinta Basin, Utah 



Formation and nature of deposits 



Geographic conditions and mammalian fauna 



Uinta of King, Marsh, and White: Diplacodon elatus beds of 

 Marsh; horizon C of Peterson, Douglass, and Riggs. Dacite 

 tuffs and sandstones, grayish and greenish. Ferruginous. 

 Thickness, about 600 feet. 



Uinta B 2 of Peterson and Osborn: Doliehorhinus cornutus 

 zone of Osborn (1895.98). Amynodon beds of Riggs (1912. 1, 

 p. 22). Coarse brownish dacite tuffs and sandstones, 

 capped at the summit by the "Amynodon sandstone," 

 immediately underlying Uinta C. Thickness, 285 feet. 



Uinta A of Peterson and Osborn, in part [Telmatotherium 

 megarhinum beds of Osborn = Metarhinus fluviatilis zone, 

 Osborn, upper Metarhinus zone of Riggs]: Capped by the 

 "Metarhinus sandstones" of Riggs, with underlying coarse- 

 grained brownish dacite tuffs and sandstone ledges; channel 

 beds, varying in thickness from 5 to 30 feet, containing 

 abundant remains of Metarhinus. Thickness, 266 feet. 



Uinta A of Peterson and Osborn, lower levels (lower Metarhi- 

 nus zone of Riggs) : Capping of columnar sandstones, under- 

 lain by friable sandy shales, interspersed with ledges. 

 Thickness, 585 feet (Douglass, 1913). Unfossiliferous. 

 Underlain by Green Ri\'or formation. 



Meadow, forest, and river fauna. Large titanotheres: Diplacodon 

 elatus, Protitanotherium emarginatum, etc. Artiodactyla: 

 Protoreodon, Leptotragulus, primitive camels. Small equines 

 (Epihippus uintensis). Other large and small members of the 

 true Uinta fauna. No traces of Amblypoda. 



Fauna chiefly stream border and fluviatile and some small 

 forms. Last uintathere (Eobasileus). Aquatic rhinoceros 

 (Amynodon intermedius) abundant. Entelodonts (Protelothe- 

 rium uintense). Rare cameloids (Protylopus) . Rare eden- 

 tates (Stylinodon). Numerous long-headed titanotheres (Doh- 

 chorhinus cornutus, D. fluminalis, Sthenodectes). In the 

 upper levels, first long-horned titanothere (Eotitanotherium of 

 Peterson) ; ancestral Symborodon-like titanotheres (Rhadinorhi- 

 nus). Titanotheres e.xtinct at this level or not recorded from 

 it are Mesatirhinus and Metarhinus. 



Abundant fluviatile and forest fauna, of small variety. Tita- 

 notheres: SmaU lowland varieties of Metarhinus very abund- 

 ant, including several distinct specific forms; also the long- 

 headed Doliehorhinus superior, the short-headed Sphenocoelus, 

 Metarhinus earlei, M. riparius, M. fluviatihs, Rhadinorhinus, 

 Doliehorhinus longiceps, an ancestral form of Dohchorhinus 

 cornutus. The amblypods Eobasileus or Uintatherium. The 

 large creodont Mesonyx obtusidens. 



No fossil mammals certainly recorded by Peterson, Douglass, or 

 Riggs from this level. 



