1920] 



Stock: An Early Tertiary Vertebrate Fauna 



269 



On the east or southeast side of Tecuja Canon, where mammalian 

 remains were first found, the Monterey has suffered greater defor- 

 mation than in the region farther to the west. 



Mammalian fossils occur nowhere abundantly in the so-called red 

 beds. The lack of large collections of vertebrates may be ascribed in 

 part to the position of the strata and in part to the fragile nature of 

 the osseous material. It is possible also that peculiar environmental 

 conditions may have been factors unfavorable to burial and preserva- 

 tion of remains, a possibility which would also account for the paucity 

 of types. The collection consists of relatively numerous individuals of 

 the genus Hypertragulus — a form related to the early camels or deer, 

 a rhinoceros, and a squirrel-like rodent. At several localities a .snail 

 of the Helix type occurs. The fossil remains were collected between 

 Salt Creek and Tecuja Cailon and to the southeast of the latter canon, 

 but from red colored deposits occurring to the west of Salt Creek no 

 material was obtained. The productive zone may be designated the 

 Tecuja beds. 



Description op Material 

 HYPEETEAGULUS, sp. 



Material representing this genus consists principally of fragmentary 

 jaws and parts of the dentition. A few skeletal structures were also 

 obtained, but no specimen was sufficiently well preserved to give the 

 essential structures of the skull. Comparison has been made par- 

 ticularly with materials referred to Hypertragulus from the John 

 Day Oligocene deposits of eastern Oregon. Judging from the remains 

 available, the California species seems to be somewhat smaller than 

 the John Day form. 



In the Tecuja Canon specimens the upper molars are preserved 

 often in series, and in several P- remains intact. P- has much the 

 shape and development of the corresponding tooth in ^lohn Day speci- 

 mens. In the molar teeth the mesostyle is absent, while the median 

 internal style is present between anterior and posterior crescents. A 

 narrow cingulum is often developed along the anterior face of the 

 molars. The degree of hypsodonty exhibited by the upper molars of 

 the Tecuja form does not appear to differ from that possessed by 

 molars from the John Day beds showing comparable stages of wear. 



In the most nearly complete lower jaw, no. 23600, figure 3, from the 

 red beds of the Tecuja Canon region, P^ is separated from Pg by a 



