ARNOLD — TUK PALEONTOLOGY AND STIIATIGKAPHY OF SAN PEDKO. 291 



The specimen filmed was (il)taiiu(I fioni the lower San Pedro series at San 

 l\'(lr(i, and is now in tlir |)rivalc collecliiHi of Delos Arnold. 



Liriiuj. — Monterey to I'anaina (("ooper): ("atalina Island, '10 fathoms 

 (ArnoKl, I'JOl). 



Pleistocene. — !^an i'cdro (Oldruyd; Arn(jld): San Diego (Cooper). 



Family LXIX. CERITIIIID.E. 



Genus Bittium Leach. 



Shell elevatt-'il, with luiinerous granular whorls and irregular varices; anterior canal short, 

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



Bittium rdiculatum Da Costa is a eliaracteristic species. 



315. Bittium asperum Gabb. 



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



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

 Pal. Cal., Vol. II, p. 72, PI. II, fig. 20, 1869. Trvon, Man. Conch., Vol. IX, p. 153, 

 PI. XXX, fig. 7, 1887. Cooper, 7th Ann. Kept. Cal. St. Min., 1888, p. 230. 



Bittium asperum 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 si.xteen to eighteen much more prominent ridges; suture deep, distinct; aperture semi- 

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

 whorl angulated, base slightly sculptured spirally. 



Dimensions. — 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 rehitive prominence of its trans- 

 verse scnl[)tiire. 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 upi)er 

 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). 



Pkidocene. — 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 Dall d; Bartsch. 



Plate IV, Fio. 4. 

 Bittium {Elachistd) caii/ornicum 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. 



