Vol. IV] ANDERSON AND MARTIN— NEOCENE RECORD 59 



This species is related to Chione securis Shumard, but differs 

 from it in having fainter crenulations, finer radial lines, curved 

 dorsal border, and narrower escutcheon. It is also much less 

 subtriangular in outline than the latter species. It differs from 

 Chione temblorensis Anderson, in not having the angulated 

 posterior ridge nor the prominent concentric ridges. 



Type: — No. 115, and cotype No. 116, Cal. Acad. Sci., San 

 Luis Obispo County, California, in a small creek about ^ of a 

 mile southwest of Lewis House, near the center of the S. E. 

 % of Sec. 22, T. 29 S., R. 16 E., Mt. D. B. L. and M. Coh., 

 Bruce Martin. 



Chione margaritana, new species 

 Plate 2, figure 1 



Shell large, su-belliptical, very inequilateral ; valves equal, 

 convex, inflated ; beaks near the anterior margin, not elevated, 

 turned forward; umbones full, narrow; liinule very large, 

 sunken, concentrically striated, bordered by narrow groove; 

 escutcheon broad and long, concentrically striated ; posterior 

 dorsal margin long, slightly arcuate ; anterior margin strongly 

 excavated in front of the beaks, rather sharply rounded near 

 the base; basal margin broadly arcuate, crenulated within; pos- 

 terior extremity evenly rounded; surface sculptured with 

 numerous coarse, nearly equally spaced, radiating ribs and fine 

 concentric striations which are irregularly raised, forming 

 concentric ruffles; the radiating ribs absent on the posterior 

 dorsal area ; interior inaccessible. 



Dimensions: — Length of the figured specimen, 108 mm.; 

 altitude, 83 mm. ; thickness of the right valve, 38 mm. 



Type: — No. 117, Cal. Acad. Sci., from the top of the Santa 

 Margarita beds in the N. E. Yi of sec. 25, T. 21 S., R. 14 E. 

 Uncommon in the Santa Margarita beds of the Coalinga region. 



Chione (Lirophora) latilaminosa, new species 

 Plate 1, figures 2a, 2b and 2c 



Shell small, trigonal, convex, depressed, very strongly char- 

 acterized by prominent lamellse ; valves equal, inequilateral ; 

 beaks prominent, turned forward, near the anterior margin of 

 the shell ; basal margin semicircular, crenulated within ; cardinal 



