SWALLOW—DESCRIPTION OF FOSSILS. 655 
the anterior extremity. Surface marked with fine concentric 
strie and obsolete plications. 
Length, 1.95; height, 1.41; thickness, 1.31. 
Rare in the Chouteau Limestone of Cooper county. 
CARDIOMORPHA (?) TRIANGULATA, Nl. Sp. 
Also found in the Chouteau Limestone of Cooper county, 
CARDINIA OCCIDENTALIS, 0. Sp. 
Shell gibbous, subovate, plicate. Valves very convex, sub- 
flattened towards the posterior cardinal border; anterior ex- 
tremity wide and regularly rounded ; ventral margin convex, 
beaks to the anterior cardinal border, straight from the beaks 
to the posterior cardinal border. Surface marked by numer- 
gularly convex ; car- 
dinal border nearly straight back of the beaks; anterior pli 
Sh aM a 
