ALASKA GEOLOGY 
IO4 
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. 
pi. 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 Dali 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 11, 
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. 
