Geological Papers. 211 



Living: Alaska to San Diego (Cooper); Quillayute Bay, Wash- 

 ington (Reagan). 



Pleistocene: San Pedro, Cal. (Arnold); San Diego to Monterey 

 (Cooper). 



Pliocene : San Fernando, Twelve Mile House, California 

 (Cooper); Quillayute, Wash. (Reagan). 



Family XXXII Psammobiid.e; Genus Tagelus Gray. 



40. Tagelus californianus Cont. Plate IV, fig. 40; times, one-half. 

 Only a fragment of a specimen of this species was obtained. 



It was found among the Maotra shells of the Quillayute forma- 

 tion from the old mouth of Maxfield creek. 



Superfamily Mactracea; family ^XXV Mactrid^. 

 Subfamily Mactrin^; Genus Mactra Linne. 



"Shell nearly equilateral; anterior hinge tooth A-shaped, with 

 sometimes a small laminar tooth close to it; lateral tooth doubled 

 in right valve; ligament set off by a shelly lamina rising between 

 chondrophore and ligament; cardinals generally coalescent above; 

 laterals smooth or finely granular." '^'^ 



Type, Mactra stultorum Linne. 



41. Mactra californica Conrad. Plate IV, fig. 41; times, one-half. 



Mactra californica Con., Jour. Phil. Acad. Sci., vol. VII, 18.37, p. 240, pi; 



XVIII, fig. 12; Williamson, Proc. U. S. Nat. Mus., vol, XV, 1892, p. 187; 



Dall, Trans. Wagner Inst. Sci., vol. Ill, part 4. 1898, p. 876; Arnold, 



Mem. Cal. Acad. Sci., vol. Ill, pp. 174-176, pi. XIX, fig. 2, 1903. 

 Standella californica Con., Carpenter, Brit. Assn. Rept., 1863, p. 640; Cooper, 



7th Ann. Rept. Cal. St. Min., 1888, p. 265. 5» 



"Shell of medium size, subtrigonal, subequilateral, compressed,, 

 thick; umbones subcentral, turned anteriorly, margin only slightly 

 arcuate; posterior side with a narrow, submarginal fold; posterior 

 extremity quite sharply rounded; ventral margin evenly arcuate; 

 surface sculptured with fine concentric lines;" interior of shell not 

 seen.''" 



A single specimen of this species was obtained from the Quilla- 

 yute formation, Middle Pliocene, at the old mouth of Maxfield creek, 

 near Quillayute, Wash. 



Living: San Diego to San Francisco (Carpenter). 



Pleistocene: San Diego, San Pedro, Cal. (Arnold). 



Pliocene: Quillayute, Wash. (Reagan). 



58. Arnold (in part). 



■59. Arnold (in part) . See above. 



