Vol. VII] DICKERSON— CLIMATE AND OLIGOCENE FAUNAS 169 



Dimensions: — Length, 6 mm. ; height, 4 mm. ; convexity, 2 

 mm. 



Type:—^o. 391, cotype 392, Cal. Acad. Sci. LocaHty 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. 



Pitaria clarki, new species 

 PI. 28, Figs. 4a, 4b and 4c 



Shell ovate, solid, concentrically sulcate ; pallial sinus ample, 

 deep, reaching the middle of shell, but slightly ascending; hinge 

 with strong lateral in left valve, weak lateral in right; lunule 

 not deeply impressed, bounded by an incised line, equally di- 

 vided between the two valves ; escutcheon elongate, poorly de- 

 fined. 



This species differs from Pitaria dalli Weaver in having a 

 less quadrate and less elongate form, in having acute — not 

 rounded — ribs, and in being less inflated. 



Dimensions: — Length of left valve, 41 mm. ; height of left 

 valve, 36.5 mm. ; convexity of left valve, 7 mm. 



Type:—]^o. 393, cotype 394, Cal. Acad. Sci. Locality 181, 

 near Vader, Lewis County, Washington, on the east bank of 

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

 four miles east of Vader. 



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

 versity of California. 



Spisula packardi, new species 



PI. 28, Figs. 5a and 5b 



Shell large trigonal, equivalve, nearly equilateral, ventricose, 

 ornamented by numerous fine concentric ridges which are more 

 pronounced and more numerous on the anterior dorsal area 

 than upon other portions of the shell ; beaks moderately prom- 

 inent; anterior dorsal area limited by a distinct ridge extending 

 from the umbo to the anterior extremity; the margin of this 

 area slightly curved ; posterior dorsal slope slightly convex, 

 limited by an indistinct ridge which extends from the beak to 

 the base of the shell ; anterior extremity more sharply pointed 



