50 [ Senate 



Strophomena radiata. 



Pal. N.Y. Vol.iii, pi. 21, f. 8 & 9. 

 Strophomaia radiata, Yanuxem, Report Third District N.Y. , p. 122, f. 6. 



Shell nearly semicircular, about three-fourths as long as wide : 

 ventral valve flat or subconcave, except near the umbo, where 

 it is depressed-convex ; beak rising a little above the line of the 

 cardinal margin : dorsal valve flat, or slightly concave near the 

 beak and towards the extremities, very gibbous in the middle 

 and towards the front ; beak not elevated above the cardinal 

 margin; hinge-line equalling the greatest width of the shell, 

 apparently not crenulated. Surface marked by distinct radiating 

 strise, which increase by implantation and bifurcation, crossed 

 by fine concentric strisB : interior indistinctly granulose. 



Geological position and. locality. Slialy limestone of the Lower Hel- 

 derLerg, Albany and Schoharie counties. 



Strophomena kadiata. 



Strophomena ( Strophodonta) punctulifera. 



Pal. N.Y. Yol.iii, pi . 21, f. 4. 



Strophomena punctulifera, Conrad : Yanuxem's Report on the Third Geological 

 District N.Y. , p. 122, f. 5. 



Shell subsemicircular, about four-fifths as long as wide : ventral 

 valve concave ; beak not projecting beyond the hinge : dorsal 

 valve concave near the umbo, very convex near the middle ; 

 beak not elevated above the cardinal margin j sides somewhat 



