104 ALASKA GEOLOGY 



MOLLUSCA 

 PELECYPODA 



Leda sp. 



Locality. Upper beds, 3373. 



A species of Leda is represented by a single crushed valve 23 mm. 

 long and 12 mm. high, rather convex, with nearly central beaks, 

 rounded in front and somewhat recurved behind. The surface appears 

 to have been concentrically somewhat irregularly, finely striated. The 

 hinge is inaccessible, and the form recalls Leda acala of the Woods 

 Bluff, Alabama, Eocene, but it is wider behind and more recurved. 



Yoldia palachei sp. nov. 



Pl. IX, fig. 4. 



Locality. Upper beds, 3373. 



Shell large, plump, smooth, rounded in front and behind, the beaks 

 somewhat nearer the anterior end; anterior dorsal slope convexly 

 arcuate, base evenly arcuate, posterior end slightly recurved, posterior 

 dorsal slope slightly concave ; hinge teeth small, about two to a milli- 

 meter; hinge largely inaccessible. Length of shell 29, height 15, 

 diameter about 8 mm. 



The form of this species recalls T. montereyensis Dall of the recent 

 fauna, but it is more slender, especially behind, and proportionately 

 more elongated. It is named in honor of Dr. Charles Palache, of 

 Harvard University, one of the geologists of the Harriman party. 



Yoldia emersonii sp. nov. 

 pi. ix, fig. 8. 



Shell of moderate size, the beaks at the anterior third, bluntly 

 rounded in front, produced, compressed, rounded and recurved behind ; 

 the base evenly arcuate, the anterior and middle parts of the shell 

 moderately convex ; the teeth small, the line of teeth rather short ; the 

 posterior dorsal slope somewhat concave. Length 18.5, height u, 

 diameter about 5 mm. 



Locality. Upper beds, 3373. 



The surface appears to have been smooth. The species is named in 

 honor of Prof. B. K. Emerson, of Amherst College, one of the geol- 

 ogists of the Harriman party. 



