270 University of California Fuhlications in Geology [Vol. 12 



diastema the length of which equals that in the John Day specimen, 

 no. 1343, Univ. Calif. Col., described by Sinclair.^ The degree of com- 

 plication of enamel jiattern in Pj is a.s great as in the corresponding 

 tooth of the John Day species. The length of the inferior tooth series, 

 Pg to Mg, inclusive, is, however, distinctly shorter than in no. 1343 

 from the John Day beds. The California specimens show closer 

 resemblance to the John Day species than to Hypertragulus ordinatiis 

 in which, according to W. D. IMatthew, Pj to M3 constitute a series 

 without diastema. //. ordinal us occurs in the Lower Rosebud (Lower 

 Miocene) of South Dakota. 



2 3 



Figs. 2 and 3. Hypertragulus, sp. Superior and inferior dentition, natural 

 size. Fig. 2, to M- inclusive, no. 23598, occlusal and lateral views; fig. 3, 

 to M5 inclusive, no. 23600, lateral and occlusal views. Eed beds, Tecuja Caiion, 

 California. 



The genus Hypertragulus is well represented in faunas of the John 

 Day deposits, where it occurs in the middle or Diceratherium beds, 

 and in the upper or Promerycochoerus beds. Dr. Matthew, who has 

 kindly furnished information regarding Hypertragulus and its geologic 

 range in the Great Plains region, states- that the genus is found in 

 the Oligocene, its vertical distribution extending upward from the 

 Lower Titanotherium beds to the Miocene. He notes further the occur- 

 rence of a species in the lower Rosebud (Lower Miocene) of South 

 Dakota; the apparent absence of the genus in the Lower Harrison 

 (upper division of the Lower Miocene) ; and the certain absence of 

 Hypertragulus in formations later in age than the Lower Harrison. 



Measurements of No. 23600 



Length of dental series, P3 to M3 inclusive 29.8 mm. 



Length of diastema behind Pj 3.6 



Depth of ramus below middle of Pj 8 



1 Sinclair, W. J., New and imperfectly known rodents and ungulates from the 

 John Day series, Univ. Calif. Publ. Bull. Dept. Geol., vol. 4, pp. 128-129, 1905. 



2 Letter addressed to writer, dated November 11, 1918. 



