ABNOLD — THE PALEONTOLOaV AND STRATIGRAPHY OP SAN PEDRO. 291 



The specimen figured was obtained from llio lower San Pedro series at San 

 Pedro, and is now in tlic private collection of Delos Arnold. 



Living. — Monterey to Panama (Cooper): Catalina Island, 20 fathoms 

 (Arnold, 1901). 



Pleistocene. — San Pedro (Oldroyd; Arnold): San Diego (Cooper). 



Family LXIX. CERlTHIIDaE. 



Genus Bittium Leach. 



Shell elevated, with numerous granular whorls and irregular varices; anterior canal short, 

 not recurved; inner lip simple; outer lip not reflected, usually with an exterior rib. 



Bittium reticulatum Da Costa is a characteristic species, 



315. Bittium asperum Gabb. 



Turbonilla aspera Gabb, Proc. Phil. Acad. Nat. Sci., 1861, p. 368. 



Bitlium asperum Gabb, Cpr., Ann. & Mag. Nat. Hist., 3rd Ser., Vol. XVII, 1866, p. 276. Gabb, 

 Pal. Cal., Vol. II, p. 72, PI. II, fig. 20, i86g. Trvon, Man. Conch., Vol. IX, p. 153, 

 PI. XXX, fig. 7, [887. Cooper, 7th Ann. Rept. Cal. St. Min., 1888, p. 230. 



Bittium asp eru7n Cpr., Williamson, Proc. U. S. Nat. Mus., Vol. XV, 1892, p. 205. 



Shell small, slender, turreted; apex elevated, acute; whorls nine to ten, nearly flat on 

 posterior portion, with prominent angulation anteriorly; sculpture consists of three spiral ridges, 

 crossed by sixteen to eighteen much more prominent ridges; suture deep, distinct; aperture semi- 

 eHiptical, with prominent basal emargination instead of a canal; lip thin, inner side crenulated; body- 

 whorl angulated, base slightly sculptured spirally. 



Dimetuiotis. — Long. 10.5 mm.; lat. 31 mm.; aperture 2.5 mm. x 1.5 mm.; defl. 22 degrees. 



This species may be distinguished by the relative prominence of its trans- 

 verse sculpture. Specimens identified by Dr. Dall 



Common in the Pliocene at Deadman Island and Timm's Point; rare in the 

 lower San Pedro series of Deadman Island, and found only occasionally in the upper 

 San Pedro series of Crawfish George's and San Pedro. Found in the Pleistocene at 

 bath-house, Santa Barbara; at Barlow's ranch, Ventura; and at Pacific Beach, 

 San Diego. 



Living. — Santa Barbara to Catalina Island (Cooper). 



Pleistocene. — Santa Barbara to San Diego (Cooper): San Pedro; Ventura; 

 Santa Barbara; San Diego (Arnold). 



Pliocene. — San Diego well (Dall): San Pedro (Arnold). 



316. .Bittium californicum Dull d: Barisch. 



Plate IV, Fio. 4. 



Bittium (^Elachista) californicum Dall & Bartsch, Nautilus, Sept., 1901, p. 58. 



Shell, small, thin, white, turreted; spire elevated, mammilliform apex; whorls eight, convex, 

 slightly more angular on anterior portion of whorl; whorls crossed by twelve or thirteen prominent. 



