1913] Dickerson: Fauna of Eocene at Mary sville Buttes 279 



some of the following to the sub-genus ClathureUa, though according to 

 those who classify by the soft parts, such divisions are of little value. 

 They must be taken for all they are worth in fossil species, as necessary 

 divisions, in the absence of better ones. 



Quite common at Marysville Buttes, where Mr. Watts and Mr. Ullrey 

 obtained 35 specimens. A very similar species inhabits the West Coast 

 of Mexico at present (S. olivacea Sby.) " 



Dimensions: Length, 37mm; width of body-whorl, 12m. 



SURCULA HOLWAYI, n.sp. 

 Plate 11, figure 9 



Fusiform, with high spire; whorls number about eight (the 

 three (?) upper whorls are missing). The fourth, fifth, sixth, 

 seventh, and eighth whorls are marked by about twelve oblique 

 nodes which extend from the angle to the suture below but do not 

 appear on the space above the angle. These nodes are crossed by 

 two prominent revolving lines. The whorls are angular with 

 vertex of the angle about two-fifths of the distance above a 

 sharply impressed suture. The space above the angle is marked 

 by minute revolving lines and by sinuous lines indicating a deep 

 sinus above the angle. 



Only one specimen was found at University of California 

 Locality 1853. Named in honor of Professor R. S. Holway, 

 University of California. 



Dimensions : Length of broken specimen, 18mm. 



SURCULA DAVISIANA (Cooper) 

 Plate 12, figures 6a and 6b 



Potamides davisiana Cooper. — Cooper, J. G., Catalogue of California 

 Fossils, Bull. 4, California State Mining Bureau, p. 44. 1894. 



"First three whorls convex, turbinate, smooth; the next six turreted, 

 increasing rapidly by wide, flattened expansions of the upper surface 

 of whorls, with a sharp raised carina half-way between the sutures, 

 from which the surfaces above and below diverge at a right angle. 

 Fourth whorl ornamented with about forty fine sharp riblets, strongly 

 curved to the left, above the carina, and giving it a serrate edge, then 

 passing down to the next suture. On the sixth whorl they are crossed 

 by two revolving riblets below the carina, and on the seventh or body- 

 whorl these increase to fifteen or more, with many intermediate smaller 

 ones, which finally entirely efface the vertical lines. Mouth triangular, 

 simple, inner edge of outer lip crenately notched, thin; (columella and 

 canal lost). Length, 1.16 inch (or more); breadth, 0.70; mouth, 0.50 



