1 899-] Matthew, Fresh-Water Tertiary of the West. 25, 



Procameltis Beds. Cyclopidius Beds. 



Fliohippus. f Pliohippus. 



Protohippus. I Protohippus. 



Hipparion. j Hipparion. 



? Mesohippus. ' ^ Desmatippus. 



I Anchippus. 



Anchitherium. 



, -r,,. •, . I Mesohippus. 



\ Phauchenia. >- ^^ 



Procamelus. ( Procamelus. 



Protolabis. 



Miolabis. 



Cyclopidius. 

 Teleoceras. Aceratherium. 



Cosoryx. Blastomeryx. 



That is to say, Horses with short-crowned teeth and Camels 

 with split metapodials persisted into the lower horizon, as 

 did also the aquatic Oreodonts and more primitive Aceratheres.^ 

 Blastomeryx characterized the lower, as Cosoryx did the upper 

 horizon. The large Teleoceras {Aphelops) fossiger, unknown irt 

 the older horizon, is the most abundant fossil of the later one. 



King ^ applied the names ' Sioux Lake ' and ' Cheyenne Lake '' 

 to the supposed lakes of the Oligocene and Upper Miocene of the 

 Plains (Miocene and Pliocene of older writers) ; and Marsh ' has 

 called the latter the Niobrara basin. The deposits cover to a 

 great extent the same area, and a single geographical name may 

 conveniently be used, as is done in the other Tertiary basins. 



The White River sediments are usually considered as lacustrine, 

 A similar origin has been assigned to all the later sediments, but 

 recent studies of Gilbert in Arkansas, Williston and others in 

 Kansas, and Darton in South Dakota, tend toward the view that 

 the Loup Fork is chiefly flood-plain sediment while the Pleisto- 

 cene is flood-plain and aeolian deposit. ■* With this view the obser- 

 vations made by the writer in Colorado in 1898 entirely coincide. 



y^ohn Day Basin. — In central Oregon. Two or three more or 

 less separate basins in the valley of the John Day River. The, 

 Cottonwood basin, containing a higher fauna, equivalent to the' 



' Two lower molars referred to Mesohippus are described by Scott and Osborn as coming 

 from the true Loup Fork of Nebraska. This is the only occurrence in the Procamelus Beds, 

 as far as I am aware. 



° 40th Parallel Survey Rep. 



^ Am. Ass. Adv. Sci., Ann. Address, 1872. 



* Gilbert, 17th Ann. Rep. U. S. Geol. Survey, 1895-6, part II, 575. Williston, Kansas 

 Univ. Geol. Survey, Rep. 1896. 



