1(1 



osborn : 



OLIGOCENE, MIOCENE, PLIOCENE EQUID.E. 



4. Deep River (Smith Creek), Montana, Cope 1879, Scott 1S93-1894, Douglass, 1899. 



5. Pawnee Creek beds, northeastern Colorado, Matthew, 1901. 



? 6. Flint Creek beds, Montana, Douglass, 1903. More probably Lower Pliocene. 



7. "Loup Fork" beds in part, Colorado and Oregon, Cope. 



8. Panhandle beds, northwestern Texas, Gidley, 1903. 



9. Sheep Creek beds, western Nebraska, Matthew, 1909. 



10. "Temblor" (Anderson, 1908), North Coalinga region, California, Merriam, 1915. 



11. Alum Bluff, Liberty County, Florida, Sellards, 1916. 



Alum Bluff, Apalachicola River, Liberty County, Fla. Sellards, 1916. 



To this newly described life zone are attributed Parahippus leoncnsis Sellards, Mcrychippus ?sp. Mesocyon, also 

 remains referred to the camel Oxydactylus ?sp. and to Leptomeryx. The Mcrychippus is regarded by Merriam as close to 

 the Phillips Ranch type of southern California (Merriam, letter Sept. 15, 1917). 



Type of Parahippus leoncnsis Sellards, 1916. Type of Mcrychippus ?sp. Sellards, 1916. 



Mascall, Oregon. 



The equine and other mammalian stages of the Mascall, Ore., are slightly earlier than those of the Deep River, Mon- 

 tana. Merriam (Trans. Am. Philos. Soc, 1915, p. 216) observes that the Mascall and Virgin Valley formations of the 

 Great Basin region are approximately of the same age as or older than the "Temblor." 



Type of Parahippus avus Marsh, 1874. Type of Mcrychippus scversus Cope, 1878. 



" " Archa-ohippus ultimas Cope, 1886. " " " rclictus Cope, 1889.1. 



" " Parahippus brevidens Marsh, 1874.4. " " " isonesus Cope, 1889.3. 

 " " Kalobatippus gracilis Marsh, 1892. 



Deep River, Montana. 

 This is regarded as slightly more recent than the Mascall. 



Type of Parahippus crenidens Scott, 1893. Type of Hypohippus equinus Scott, 1894. 



Sheep Creek, Western Nebraska. 



The Sheep Creek deposits doubtless extend over a considerable period of time. They have yielded referred specimens 

 of Parahippus aims, also a series of primitive types of Mcrychippus (M. isonesus primus Osborn) which lead into more 

 progressive types (ilf. isonesus quintus Osborn). The geologic distribution of these ascending mutations which lead up 

 into Mcrychippus scversus or M. isonesus is indicated in the accompanying diagram. This series of Mcrychippus are less 

 primitive than the Parahippus brevidens Marsh of the Mascall. 



A referred specimen, M. isonesus primus Osborn (Amer. Mus. 14179a), was found about a half a mile away, appar- 

 ently at a lower geologic level than the type of this species, Amer. Mus. 14187. A referred specimen of Parahippus avus 

 (Amer. Mus. 14182) came from the same locality as 14179-85. 



Relations of the Phillips Ranch and Cache Peak Faunas, Tehachapi, Southern California. 



" A comparison of the Phillips Ranch and Cache Peak faunas must at present be based largely upon the horses repre- 

 sented in the two collections. Moropus occurs only in the former fauna, while Mcrycochwrus (?) and Dromomeryx are 

 found only in the latter, but the collections are not sufficiently large to make the absence of a form from one fauna and 

 its presence in the other significant. Merycodus is present in the collections from both localities, but the material is too 

 scanty to allow an accurate comparison." (p. 81.) "The faunas, consisting as they do in large part of horses, camels, 



