AKNOLD — THE PALEONTOLOGY AND STRATIGRAPHY OF SAN PEDRO. 221 



201. Olivella pedroana Conrad. 



Strepho7ia pedroana Con., Pac. R. R. Rept., Vol. V, p. 327, PI. VI, fig. 51, 1854. 



Olivella bwtica Cpr., Brit. Assn. Rept., 1863, p. 661. Gabb, Pal. Cal., Vol. II, p. 75, 1869. Tryon, 

 Man. Conch., p. 71, PI. XVII, figs. 28, 31, 34, 1883. Cooper, 7th Ann. Rept. Cal. St. 

 Min., 1888, p. 255. Keep, West Coast Shells, p. 42, fig. 21, 1892. Williamson, 

 Proc. U. S. Nat. Mus., Vol. XV, 1892, p. 212, PI. XIX, fig. 7. 



Shell small, elongate; spire elevated; apex acute; whorls five, flat, smooth; suture appressed, 

 very distinct; aperture elongate-triangular; outer lip thin; inner lip callous; lower part of columella 

 incrusted; columellar plication divided by median groove. 



Dimensions. — Long. 12.9 mm.; lat. 5 mm.; body-whorl 9.4 mm.; aperture 7.2 mm.; defl. 

 40 degrees. 



Distinguishable from 0. intorta by double columellar plication, smaller callus, 

 slenderer form, sharper apex and straighter outer lip; distinguishable from 0. hipli- 

 cata by slenderer form, smaller size, and more elevated spire. 



Common in upper San Pedro series of Los Cerritos; rare in upper and lower 

 Ban Pedro series, and Pliocene of San Pedro and vicinity. Found also in the 

 Pleistocene at Spanish Bight and Pacific Beach, San Diego, and at Barlow's ranch, 

 Ventura. 



Living. — Straits of Fuca to San Diego (Cooper). 



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

 San Diego (Arnold). 



Pliocene. — Seven Mile Beach; Twelve Mile House; Kirker's Pass; San Diego 

 well (Cooper). 



Family LV. MARGINELLID.E. 



Genus Marginalia Lamarck. 



Shell ovately oblong to subcylindrical, smooth, polished, sometimes longitudinally ribbed; 

 spire short, conical, or concealed; aperture narrow, elongated, obtuse or truncated in fi'ont; columella 

 plicate; outer lip with a thick marginal varix, its inner margin smooth or crenulated. 



Marginella glohella Linn, is a characteristic species. 



202. Marginella jewettii Carpenter. 



Margi7iella jewetiii Cfk., Proc. Zool. Soc, 1S56, p. 207; Brit. Assn. Rept., 1S63, p. 661. Trvon, 

 Man. Conch., Vol. V, p. 43, PI. XII, fig. 57, 1883. Cooper, 7th Ann. Rept. Cal. St. 

 Min., 1888, p. 249. Dall, Trans. Wagner Inst. Sci., Vol. Ill, Part i, 1890, p. 57. 

 Keep, West Coast Shells, p. 43, fig. 23, 1892. Williamson, Proc. U. S. Nat. Mus., 

 Vol. XV, 1892, p. 212, PL XIX, fig. 6. 



Shell small, smooth, ovate-oblong; spire barely visible; aperture not extending fijll length 

 of shell, narrow, elongated, obliquely truncated in front; outer lip thickened with marginal varix, 

 its inner side smooth; columella with three prominent plications near anterior end, and lesser 

 ones above. 



Dimensions.- — Long. 5 mm.; lat. 3 mm.; aperture 4.7 mm. 



Specimens identified by Dr. Dall. 



