INTRODUCTION 



in Nordamerika so stark vertretenen Vorlaufern der Camelina (Oreodon, Pro- 

 camelus, Leptauchenia, etc.), hinzudeuten und denjenigen von Tragulina und 



Cervina sehr fern zu stehen Nach jeder Richtung scheint mir also 



Leptomeryx den hornlosen Wiederkauern des europaischen Miocens sehr fern 

 zu stehen." ('83, pp. 98-9.) 



The Uinta beds are confined to the comparatively small basin in North- 

 western Colorado and Northeastern Utah which lies to the south of the 

 Uinta Mountains. They directly overlie the strata of the upper Bridger 

 (Washakie substage), and according to Peterson are divisible into two horizons, 

 which he calls B and C. (See Osborn, '95, pp. 72—76.) The lower horizon, 

 B, is transitional from the Bridger, while the upper beds, C, constitute the 

 typical Uinta. Peterson says of them : " We now reach the true Uinta, or 

 Brown's Park, beds of a fine-grained, soft material, much the same in appear- 

 ance as the characteristic Bad Lands of South Dakota, with the exception of 

 the color, which is a brick red ; in fact, the reddish tinge holds good through- 

 out the Uinta sediment These uppermost strata of the Uinta basin 



have hitherto been reported (by C. A. White) as resting unconformably upon 

 the underlying Bridger sediment, but no observable breaks were found to dis- 

 tinguish the true Uinta from the underlying Bridger sediment." (Loc. cit., p. 74.) 



On the other hand, Hatcher believes that there is a distinct angular un- 

 conformity between the horizons B and C. In favor of this opinion is the 

 unquestioned fact that the upper beds (C) overlap the lower (B) towards the 

 north, extending over upon the upturned Cretaceous and older rocks, which 

 form the flanks of the Uinta Mountains. 



The north to south extension of the beds is not great at present, but, 

 doubtless, has been very much reduced by denudation along the southern edge. 



The position of the Uinta formation in the geological column is perfectly 

 clear, both upon stratigraphical and palaeontological grounds; it succeeds the 

 Bridger and precedes the White River in time. It has been customary to call 

 the Uinta beds Upper Eocene, but much may be said in favor of regarding 

 them as Lower Oligocene. The Uinta, White River, and John Day form three 

 successive stages, whose mammalian faunas are most closely connected, and 

 were the American time-scale constructed without reference to that of Europe, 

 no student of these horizons would think of distributing them among different 

 periods. Clearly, the natural arrangement is to make them three stages of 

 one period or system. In the intere.sts of palaeontology it is fortunate that 



