304 University of California Publications in Geology [Vol. 9 



Locality 785, which is described by R. E. Dickerson as follows: 

 "Vicinity of Lower Lake, Lake County, Tejon Group. NW *4 of 

 SE % of Sec. 6, T 13 N, R 6 W, in a west gully near hill top. Ele- 

 vation 1750 feet." 



Occurrence. — Eocene : Tejon group, Lower Lake and Mount 

 Diablo, California. 



Genus Mulinia Gray, 1837 



Type Mactra typica Gray 



Ligament and resilium not separated, entirely internal; teeth 

 not concentrated ; laterals subequal ; valves not gaping. Pallial sinus 

 small and short. 



MULINIA DENSATA Conrad 

 Plates 29, 30, 31, 32 and 33 



Muli7iia densata Conrad, Proc. Acad. Nat. Sci. Phil., December 1856, 

 p. 313; Pacific R. R. Repts., vol. 6, p. 71, pi. 3, fig. 12, 1857; Gabb, Pal. 

 Cal., vol. 2, p. 19, pi. 5, fig. 35, 1869 (in part); Arnold, U. S. Geol. Surv. 

 Bull. 396, p. 55, pi. 21, fig. 3, 1909. 



Cardium gabbii Remond, Proc. Cal. Acad. Sci., vol. 3, p. 13, 1863. 



Pseudocardium gabbii (Remond), Gabb, Pal. Cal., vol. 2, p. 21, pi. 6, 

 figs. 45a, b and c, 1869. 



Mulinia oregonensis Dall, U. S. Geol. Surv. Prof. Paper 59, p. 132, pi. 9, 

 figs. 2 and 3 and pi. 13, fig. 5, 1909. 



This species was described by Conrad as follows : 



Subovate, ventricose, thick, very inequilateral; posterior side very short 

 comparatively, contracted; extremity subtruncated, much above the line 

 of the base; posterior basal margin very oblique and contracted; anterior 

 end obliquely truncated; anterior basal margin rounded; summits promi- 

 nent, distant; external teeth very robust and prominent; inner margin 

 entire. The length of the type is equivalent to 73 mm. The height as 

 measured on the original figure is 58 mm. 



Conrad's original description of Mulinia densata was supple- 

 mented by a figure which was later criticized by Gabb, who con- 

 tended that the species was based upon a contorted specimen. Gabb 

 redescribed the species, basing his description upon a specimen ob- 

 tained from near San Pablo Bay, California. He appeared to base 

 his conclusions upon the general shape of the shell, for he failed to 

 note that Conrad's species was described as having "very robust 



