ARNOLD — THE PALEONTOLOGY AND STRATIGRAPHY OF SAN PEDRO. 271 



portion of the whorls, but fuse anteriorly before reaching suture; the ribs are bent slightly forvvaid 

 near their posterior extremity; intercostal spaces deep, narrow; spiral sculpture fine but conspicu- 

 ous; the sutures are deeply impressed, with smooth sides, caused by the fusion of the ribs before 

 reaching the sutures; body-whorl rounded, smooth below, except for minute incremental lines and 

 spiral ornamentation. Aperture subquadrate; the outer lip joins the straight, somewhat revolute 

 columella at a right angle. 



Dimensions. — Long. 5 mm ; hit. i.i mm.: altitude of hody-wiiorl 1.4 mm. 



Tliis species; soinowliat losenibles T. sledrmfii, but is distiiiguislial)le from tliat 

 species by tiie less miiubef and greater prominence of the ribs, which in some cases 

 bend slightly forward near their posterior extremity. T. sbniUs was identified by 

 Dr. Dall; but the species was omitted from the te.xt prepared by Dall and Bartsch. 



Rare in the lower San Pedro series at Deadman Island and San Pedro; 

 common in the upper San Pedro series at San Pedro and Los Cerritos. 



Living. — Gulf of California to Panama (Carpenter). 



Pleistocene. — San Pedro (Arnold). 



286. Turbonilla (Strioturbonilla) stearnsii D. I- B., s\>. uov. 



Plate II, Figs. 5 and 5a. 



Shell milk-white, rather stout; nuclear whcfrls two, small, helicoid, their axis being at right 

 angles to the axis of the po.st-nuclear whorls; post-nuclear whorls very sligiitiy convex, almost 

 tiattened, somewhat contracted at the base, and strongly shouldered at the summit, traversed by 

 eighteen to twenty-six oblique, flexuose, axial ribs, which render the summits of the wnorls wavy; 

 intercostal spaces deep, terminating a little above the periphery, thus leaving a narrow, plain band 

 above the suture, as in T. iorquata stylina; the entire surface of the whorls is marked by numerous 

 faint, wavy, spiral striations, which also ornament the otherwise plain basal portion of the last whorl; 

 suture well defined, slightly channeled; aperture subovate, anterior angle obtuse; outer lip thin, 

 joining the short, somewhat revolute columella in a gentle curve. 



Dimensimis. — Long. 9.2 mm.; diam. 2.3 mm. 



The type, which has eleven anci one-half post-nuclear whorls, is from the post- 

 Pliocene of San Diego. 



This species in a general way resembles T. torquata dylina, but differs from it 

 in being much more robust, of greater diameter throughout, and in having the fine, 

 wavy sculpture characteristic of the section. 



Tnrhondln ( SirioturbonillnJ stearnsii occurs quite abundantly in the post- 

 Pliocene deposits at San Diego and San Pedro. It also occurs recent in the Gulf of 

 California. The name is proposed in honor of Dr. R. E. C. Stearns of Los Angeles, 

 who collected many specimens of this group. 



287. Turbonilla (Strioturbonilla) torquata Gould. 



Pl.ATK II, Flli.S. 4 A.NI) 4«. 



Chemnilzia Iorquata Gi.D., Bost. Jour. Nat. Hist., Vol. IV, 1853, p. 384, PI. XIV, fig. 16. 



Shell slender, solid, milk-white, entire surface marked by faint, wavy, spiral striations; 

 nuclear whorls three, helicoid, their axis being at right angles to and to one side of the post-nuclear 



