164 



osborn: oligocene, Miocene, pliocene eqtjidje. 



Pliohippus fairbanksi Merriam 1915. 

 Text Fig. 131. 



Pliohippus fairbanksi, n. sp., Merriam, John C. "New Horses from the Miocene and Pliocene of California," Univ. Cal. Piibl. 

 Bull. Dept. Geol. Vol. 9, No. 4, Nov. 22, 1915, pp. 55-56, figs. 8a-8c. 



Horizon and locality. — "... .from the Rieardo Pliocene, near Ricardo Postoffice; California." Mohave Desert. 

 Type collected by the expedition of the University of California. 



Type. — Univ. Cal. Pal. Coll. 19789. (Merriam) a large unworn upper cheek-tooth p 4 ?." Measurements: 



p 4 , height of crown on outer side .055, a. p. .025, tr. .0264. 



Type figure. — Text Fig. 131 of this Memoir. 



8b 



Fig. 131. Original figures of the type of Pliohippus fairbanksi Merriam, Univ. Cal. Pal. Coll. 19789, p 4 (?). (8a) 

 Crown view, (86) section taken across upper third of crown, (8c) posterior view. Natural size. After Merriam, 1915, 

 p. 55. 



Characters. — (Merriam, 1915, p. 55) (1) A protohippine form differing considerably from Pliohippus tantalus of the 

 Ricardo Pliocene. (2) Crown a little more strongly curved; (3) para-, meso-, and metastyles heavier, fossettes narrower 

 and of a different form; (4) protocones small, round, united with protoconule after wear; (5) protoconule remaining 

 separate from metaconule almost to the base of the tooth; (6) no indication of pli caballin; (7) single fold projecting from 

 metaloph into prefossette and postfossette. 



PLIAUCHENIA-PLIOHIPPUS SPECTANS ZONE. 15. MIDDLE PLIOCENE. 



The typical exposures are the Rattlesnake, Oregon, containing the typical type Pliohippus spectans 

 Cope. 



Pliohippus spectans Cope 1880. 

 Plate 28.2. Text Fig. 132. 



//. spectans, Cope, E. D. "A New Hippidium," Amer. Naturalist, Vol. XIV, No. 3, Mar., 1880, p. 223, no figure. "The Perisso- 

 dactyla," Amer. Naturalist, Vol. XXI, No. 12, Dec, 1887, p. 1072, fig. 41, a, b. 



Horizon and locality. — "Loup Fork" beds, Cottonwood Creek, Oregon, "almost certainly Rattlesnake formation." 

 (J. C. Merriam, Jan. 3, 1917) Middle Pliocene. Type collected by Professor Thomas Condon. 



