Vol. VII] WARINGSTRATIGRAPHIC AND FAUNAL RELATIONS 87 



flattened ; body-whorl oblique, ornamented by numerous band- 

 like, revolving ribs, with linear interspaces ; surface also marked 

 by sinuous lines of growth which give the revolving ribs a wavy 

 appearance ; umbilicus imperforate ; umbilical margin acutely 

 rounded ; aperture distended, subelliptical ; outer lip acute, inner 

 lip slightly thickened. Locality 4, L. S. J. U. Pal. Coll. 



This species differs from Natica lincata Dickerson^** by hav- 

 ing an imperforate umbilicus. 



Named for Dr. Roy E. Dickerson, Curator of Paleontology, 

 Cal. Acad. Sci. 



Trachytriton titan, new species 



PI. 14, Fig. 18 



Shell very large, fusiform, thick; spire elevated, whorls five, 

 subangulated, nodose ; aperture broad, anterior end narrowing 

 into the canal ; posterior rounded ; whorls slightly convex 

 above, concave below ; body whorl below ornamented by coarse 

 spiral ribs; about 15 tubercles ornament the angle of the body- 

 whorl. Locality 4, L. S. J. U. Pal. Coll. 



This species is very similar to T. tcjoncnsis Gabb,^^ but is 

 larger, has thickened shell, more numerous tubercles, and the 

 whorls are more angular. 



Turritella maccreadyi Waring 



PI. 12, Fig. 10 



T. maccreadyi Waring, Jour. Geol., vol. 22, no. 8, p. 783, 

 Nov.-Dec, 1914. 



Shell robust, apical angle broad; whorls 11, rounded, with 

 six or seven strong, nearly equally spaced, spiral ribs ; first five 

 or six whorls angulated as in T. martiuccciisis Gabb ;^" surface 

 below body-whorl also ornamented by spiral lines, and whole 

 surface marked by lines of growth ; aperture broad, outer lip 



»»Bull. Dept. of Gcol., Univ. Calif., vol. 8, no. 6, p. 141, pi. 13, fig. 3a. 

 " Pal. Cal., vol. 2, p. 154, pi. 26, fig. 34. 

 o-Pa\. Cal., vol. 2. p. 169, pi. 28, fig. 51. 



