214 TRANS. OF THE ACAD. OF SCIENCE. 
Length of cardinal line, 0.60; greatest breadth of shell, 1.56; 
height from beak to base, 1.58. 
jor Hawn’s collection, sg the Coal Measures in the 
valley of the Verdigris, K 
PINNA PERACUTA, Shumard. 
Of op sig the Asai: Ee contains nothing more ha 
"the shell is very thin, conic o-ring ST gradually 
lines of growth) i ae is song rounded ; the beak in is acute a 
tapering ; or t° prominent t above the middle, gently 
roormegna above the preter and flattened below to the pal- 
- Geol. Pos. and Loc.—Occurs in the Upper Coal Measures of 
the Missouri River, near Iowa Point, where it was. found by 
Prof. ee waa Major Hawn also found it in the same a 
gical pc pin localities in Kansas Ter. oe 
a tik RETIFERA, Shumard. 
ses ell ral, rather small, cheeks. oblique, some- 
wh: comme convex, ea ee greater than the width; 
whi sty biftcets ne : i : 
sie umbonial Set oly e ribs are } in- 
