HIPPARION. 



187 



Horizon and locality. (Cope) Type locality, Palo Duro Canon, Crosby County, Texas; paratype locality Mulberry 

 Canon near Goodnight, Texas, Clarendon formation ("Goodnight beds"), Upper Miocene. Type collected by F. W. 

 Cummins. 



Type. — Univ. Texas Coll. (cast Am. Mus. 14391). (Cope) A broken lower molar. Measurements: (Cope, 

 p. 44) a. p. diameter of crown at middle .020, transverse width of crown restored .011, a.p. diameter of metaconid- 

 metastylid column .013. Paratypes: four inferior molars (molars and premolars) from Mulberry Canon near Goodnight 

 Ranch, Texas, represented in Plate XII, Figs. 8, 8a, 8b. 



Type figure. — Text Figs. 149 of this Memoir. 



Characters. (Cope) (1) Of small size. (2) Relative great width of the metaconid-metastylid column; (3) close 

 appression of this column to the protoconid and hypoconid. (For further description see Cope, op. cit.) 



Gidley observes (1907, p. 918) that the type tooth is so fragmentary as to show no particularly distinctive features. 



The type is, in fact, indeterminate. The characters derived from the paratypes are invalid because certain of them 

 (such as the teeth represented in Cope, plate XII, 7, 7a, 8, 8a) certainly belong to other species. 



The type teeth may be identified with the genus Hipparion; the species is wholly indeterminate. 



Fig. 150. Original figures of the type of Hipparion gidleyi Merriam, Univ. Cal. Pal. Coll. 21382, m 3 . External and 

 crown views. Natural size. After Merriam, 1915, fig. 1, p. 2. 



Hipparion gidleyi Merriam 1915. 

 Text Fig. 150. 



Ncohipparion gidleyi, n. sp., Merriam, John C. "New Species of the Hipparion Group from the Pacific Coast and Great Basin 

 Provinces of North America," Univ. Cal. Publ. Bull. Dept. Geol. Vol. 9, No. 1, June 29, 1915, pp. 1-2, fig. 1. 



Horizon and locality. — (Merriam) "Probably from a stratum just below the coal seam at a mine on the Lawler 

 Ranch, six miles east of Petaluma, California. The formation has been doubtfully referred to the San Pablo Miocene, 

 but may represent a later period." No horses are certainly known in the San Pablo. Type collected by Mr. Lawler. 



Type. — Univ. Cal. Pal. Coll. 21382. A third upper molar, m 3 , of the left side. Measurements: (Merriam, 1915) 

 m 3 a.p. .0267, tr. .0200; a.p. of protocone .01S7, height of worn crown .0555. 



