Geological Papers. 187 



Genus Metis H, & A. Adams. 



Shell slightly inequivalve, suborbicular, compressed ; valve sil- 

 lonated; posterior flexuosity submedian; no lateral teeth. A char- 

 acteristic species is lellina meyeri Phil. 



18^. Metis alta Conrad. 



Only the impression of the shallower valve with the angular 

 groove was obtained, but enough to determine the species. 



Specimen obtained from the middle series at East Clallam. 



Super,family Mactracea; Family XXXV MACTRiDiE. 

 Subfamily Mactrin.e; Genus Mactra Linne. 



Shell nearly equilateral; anterior hinge tooth A-shaped; lateral 

 tooth doubled in right valve; ligament and resilum separated by a 

 shelly partition; cardinals generally coa.lescent above; laterals gen- 

 erally smooth, occasionally granular. 



Type, Mactra stultorum Linne. 



19. Mactra gibbsana Meek. Plate II, figs. 19a, 196. 



Matra gibbsana Meek, 1861, Proc. Acad. Nat. Sci. Phil., vol. XIII, p. 315; 

 Bull. U. S. Geol. & Geogr. Surv. Terr., vol. II, No. 4, p. 374, pi. 2, figs. 

 8, 8a-b, 1876. 



Meek's description (see Geol. & Geogr. Terr, above): "Shell 

 transversely oval, or subtrigonal, moderately convex, rather thin; 

 anterior side narrowly rounded; base forming a regular semi-ellip- 

 tical curve; posterior side slightly truncated at the immediate ex- 

 tremity, abruptly rounded or subangular at its connection with the 

 base below; dorsal outline sloping from beaks in front and behind 

 at an angle of about 120 degrees; beaks central, rather elevated? 

 but small and not projecting much above the hinge margin; sur- 

 face marked only by moderately distinct lines of growth; posterior 

 muscular impression oval, well defined; pallial line distinct and 

 provided with a rather deep, horizontal sinus which is about one- 

 third longer than wide." 



This species is very abundant in all the series of the Clallam 

 formation exposed along the Strait of Fuca, but most abundant in 

 the lower series at East Clallam. 



Dimensions: Length, 55; alt., 41; diam., 24. 



Cretaceous or Tertiary(?): Float in Strait of Juan de Fuca 

 (Meek). 



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



Superfamily Myacea ; Family XXXVIII, Saxicavid.e, 

 Genus Paopea Menard. 



Shell large, thick, equivalve, oblong, gaping widely behind and 

 slightly in front; ligament external, on prominent ridges; an ob- 



