180 CALIFORNIA ACADEMY OF SCIENCES [Proc. 4th See. 



scure spiral threads on fourth and fifth whorls ; aperture sub- 

 quadrate ; outer lip thin. 



Dimensions: — Length, 4 mm. ; width of body-whorl, 1 mm. 



Type: — No. 433, Cal. Acad. Sci. Locality 181, near Vader, 

 Lewis County, Washington, on east bank of Cowlitz River, 

 just back of the Greeco ranch house, about four miles east of 

 Vader. Colls., F. M. Anderson and Bruce Martin. 



Named for Dr. B. L. Clark, Instructor in Paleontology, Uni- 

 versity of California, whose recognition of the Agasoma gravi- 

 duni zone as Oligocene has been of great service to the strati- 

 grapher and paleontologist. 



Seraphs andersoni, new species 

 PI. 31, Figs. 9a and 9b 



Shell, smooth, spindle form, with five whorls; the body- 

 whorl swollen and five times as long as spire; spire whorls 

 nearly flat-sided; suture linear; outer lip, thin, sharp; aper- 

 ture elongate, narrow; canal short, slightly twisted toward the 

 rear. 



This form is less elongate than Seraphs erraticus (Cooper) 

 from the Tejon Eocene of California and the body-whorl is 

 much wider. 



Dimensions: — Length, 38 mm.; width of body-whorl, 11 

 mm. 



Type: — No. 434, and cotype No. 435, Cal. Acad. Sci. Local- 

 ity 181, near Vader, Lewis County, Washington, on east bank 

 of the Cowlitz River, just back of the Greeco ranch house, 

 about four miles east of Vader. Colls., F. M. Anderson and 

 Bruce Martin. 



Named for Mr. F. M. Anderson, who collected this species 

 at its type locality. 



Hipponyx arnoldi, new species 



PI. 31, Figs. 10a, 10b, 10c and lOd 



Shell oval, low with anterior meeting dorsal surface at an 

 acute angle at apex; growth stages very prominently marked 

 by shingle-like edges of the successive margins ; a great number 



