1922] Fauna from the Eocene of Washington 21 



impressed and bound by an incised line; escutcheon very narrow; surface orna- 

 mented with numerous, lamellar, concentric ribs with interspaces about three 

 times the width of the ribs. 



This shell is like that figured by Dr. Dickerson in the Prod. Cal. Acad. Sci., 

 vol. V, no. 3, pi. 3, figs. 2a, b, to which he gave the new name Meretrix 

 tejonensis to replace Meretrix uvasana Gabb. Pitaria eocenica n. sp. differs from 

 Meretrix uvasana Gabb in smaller size, a more ovate shape and the posterior end 

 more rounded and less attenuated. 



Dimensions. Length 25 mm. ; height 22 mm. ; thickness 16 mm. 



Occurrence. At locality 329 (University of Washington Palaeontological 

 Collection) west bank of the Cowlitz River, near Vader, Lewis County, Section 

 28, Township 11 North, Range 2 West. 



PITARIA STOCKI n. sp. 

 Plate X, Figure 6 



Description. Shell medium in size and ovate in outline ; very convex ; beaks 

 small ; anterior end short, slightly curved, extending from the beaks at an angle 

 of 55; ventral margin arcuate, rounding into the anterior and posterior ends; 

 surface ornamented with numerous flat, concentric ribs with interspaces about 

 half the width of the ribs ; concentric ribbing more pronounced on the anterior 

 and posterior slopes and on the lower part of the shell; a very large lunule, 

 extending nearly the length of the anterior end ; lunule bounded by an impressed 

 line; teeth normal. 



Named in honor of Dr. Chester Stock of the Paleontology Department, Uni- 

 versity of California. 



Dimensions. Length 24 mm. ; height 22 mm. ; thickness 14 mm. 



Occurrence. At locality 320 (University of Washington Palaeontological 

 Collection) south bank of Stillwater Creek below the graveyard, about one and 

 one-fourth miles from Vader, Lewis County, .Section 30, Township 11 North, 

 Range 2 West. 



GENUS MACROCALLISTA MEEK 



MACROCALUSTA WIUJAMSONI n. sp. 



Plate X, Figures 1, 11 



Description, Shell large, oval-elongate in outine ; inequilateral, breaks situ- 

 ated about one-fourth of the distance from the anterior end; beaks moderate in 



