Geological Papers. 181 



Superfamily Veneracea; Family XXVII Venerid^. 

 Subfamily VENERlNiE; Genus Venus Linne. 



"Shell thick, ovate, smooth, sulcated, or cancellated; margins 

 minutely, crenulated; cardinal teeth, three in each valve; pallial 

 sinu8 small, angular; ligament prominent; lunule distinct." 



Subgenus Chione Megerle. 



"Shell oval, triangular or subcordiform; margins finely crenu- 

 lated; hinge narrow, solid, with three teeth in the right valve and 

 two in the left, the interior tooth longest; ligament narrow; pallial 

 .sinus shallow. Venus gnidia Brod. is a characteristic species."'"* 



8. Venus {Chione) vespertina, Conrad. Plate I, fig. 8; times, one-half. 

 Cytherea vespertina Con., Am. Jour. Sci., 1848, p. 432, fig. 9. 



Dione vespertina Con., Jour. Conch., 1865, p. 152. 



Conrad's description:*^ "Acutely ovate, ventricose, very inequi- 

 lateral; summits prominent; surface with concentric lines which 

 are not very smooth and regular; posterior side somewhat cunei- 

 form ; anterior extremity acutely rounded ; basal margin rounded." 



The cast of a single specimen was obtained from the lower shalet- 

 near Gettysburg. 



Miocene : Oregon ( Conrad ). 



Oligocene-Miocene : Gettysburg, Wash. (Reagan). 



9. Venus (Chione) angustifrons Conrad. Plate I, fig. 9; times one- half. 



Venus angustifrons Con.,' Wilkes's Expl. Exped., vol. X, p. 724, pi. 17, 



fig. II. 

 Dione angustifrons Con., Jour. Conch., 1865, p. 152. 



Conrad's description:*^ "Subtrigonal, ventricose; ligament' 

 margin very oblique and slightly curved; long posterior margin di- 

 rect, truncate; basal margin arcuate; latter surf ace everywhere con- 

 vex, and having thin, concentric, elevated lamellse." 



Specimen figured is a cast from the lower shales at Gettysburg, 

 Wash., the only specimen obtained, except one which was found 

 in the lower series at East Clallam. 



Miocene: Astoria, Ore. (Conrad). 



Oligocene-Miocene: Snohomish, Wash. (Arnold); East Clal- 

 lam, Gettysburg (Reagan). 



10. Venus {Chione) mathewsonii Gabb. 



Chione mathewsonii Gabb., Pal. Cal., vol. //, p. 23, 1869. Plate I, fig. 10; 

 times, one-half. 



Shell large, very thick, subcordiform to subtriangular and ob- 

 liquely cordate ; beaks small, pointed forward and placed well an- 



40. Arnold, loc. cit., pp. 146, 147. 



41. Am. Jour. Sci. above. 



42. Wilkes's exped. above. 



