1922] Fauna from the Eocene of Washington 19 



GENUS VENERICARDIA I.AMARCK 



VENERICARDIA CLARKI n. sp. 

 Plate IX, figures 4, 5 ; Plate X, Figure 8 



Description. Shell small and ovate ; umbones small ; anterior end slightly 

 produced, sloping from the beaks at an angle of 20, rounding into the ventral 

 margin ; ventral margin regularly rounded ; posterior end rounded, passing from 

 the ventral margin at about the same degree of convexity as the anterior end ; 

 posterior dorsal margin nearly straight or slightly curving to the posterior end ; 

 surface ornamented with 18 to 20 very well developed radiating ribs with rounded 

 interspaces about half the width of the rib ; the median portion of the ribs is 

 raised and rounded, the base forming a lower ridge on each side of the ribs, 

 giving them a tripartite character; the median, raised portion of the ribs is 

 ornamented by fine nodes or pustules which occur on all the ribs on very young 

 shells, and on the umbonal region and the anterior end of most of the shells ; the 

 ribs on the posterior end of the older specimens become broader and the pustulate 

 condition obliterated; inner margin fluted. 



Dimensions. Length 17 mm.; height 15 mm.; thickness 11 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. 



VENERICARDIA CRESCENTENSIS n. sp. 

 Plate X, Figure 9 



Description. Shell small and subquadrate in outline ; posterior dorsal line 

 straight, slightly oblique; posterior margin straight, extending almost at a right 

 angle to the dorsal margin and abruptly passing into the ventral margin which 

 curves slightly to the anterior end ; anterior moderately produced ; surface orna- 

 mented with 22 wide, flat-topped, radiating ribs with interspaces about one-third 

 of the width of the ribs ; on the posterior dorsal region the ribs become narrower 

 and the interspaces wider; an umbonal ridge extends from the beaks to the 

 posterior ventral point. 



Dimensions. Length 15 mm. ; height 12 mm.; thickness 10 mm. 



Occurrence. At locality 358 (University of Washington Palaeontological 

 Collection) at Joice station, one-fourth of a mile east of Tongue Point railroad, 

 Port Crescent, Clallam County, Section 22, Township 31 North, Range 8 West. 



