1913] Dickerson: Fauna of Eocene at Marysville Buttes 275 



two much smaller cusps on either side of the median one. They 

 are both convex on the inner and outer sides. 

 University of California Locality 1853. 



Dimensions : Greatest length of middle cusp, 9mm ; greatest 

 transverse diameter of base, 11mm. 



TURRIS MONOLIFERA (Cooper) 

 Plate 11, figure 1 



Surcula monolifera Cooper. — Cooper, J. G., Catalogue of California 

 Fossils, Bull. 4, Cal. State Mining Bureau, p. 39, 1894. 



"Fusiform; nuclear whorls three, smooth, conical; the next crossed 

 by twelve or more strong, oblique riblets, which change on fourth or 

 fifth into a row of beaded knobs, forming an angle along middle of 

 whorls, increasing to thirty-five on ninth or body-whorl. Above this angle 

 are nine or ten fine revolving riblets, and three or four below it, the two 

 posterior being longest, and imperfectly beaded at the suture. On the 

 anterior whorls the medial knobs are sometimes doubled, and on the body- 

 whorl the revolving riblets are alternately large and small. Canal straight, 

 equaling the sub-oval mouth in length. Sinus deep, situated at the angle. 

 Length, 0.60 inch ; breadth, 0.08 ; mouth and canal, 0.34 long. 



Five specimens obtained, agreeing well in characters, at Marysville 

 Buttes, by Mr. Watts. This is quite near to Gabb 's " Turris claytonensis, " 

 from near the Mt. Diablo coal mines, but a comparison with his description 

 shows marked differences. Figures three times the natural size. 



The occurrence of seven new Pleurotomidae without many other univalve 

 shells, and especially the absence of the many forms of genera allied to 

 Fusus described by Gabb, is a condition of distribution indicating prob- 

 ably that a warmer sea existed where they are found, than at most localities 

 of similar age in California. ' ' 



Abundant at University of California Localities 1853 and 

 1856. 



Dimensions : Length, 9mm ; width of body whorl, 4mm. 



TURRIS ANDERSONI, n.sp. 

 Plate 11, figure 2 



Shell fusiform with rather short spire and a long body-whorl. 

 Whorls, about seven (two upper whorls missing), rounded, nodose. 

 The whorls are marked by eight rounded vertical nodes which 

 extend from a well marked suture over the entire whorl. The 

 lines of growth indicate a moderately deep sinus at the angle. 

 Mouth, oval, narrowing abruptly at a point about two-fifths of 

 the distance below the suture into a long narrow canal. Inner 

 lip, smooth. 



