50 ' [ Senatk 



Strophomena radiata. 



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

 Strophomena radiata, Vanuxem, Report Third District N.T., 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 

 striffi, which increase by implantation and bifurcation, crossed 

 by fine concentric strise : interior indistinctly granulose. 



Geological positioii and locality. Shaly limestone of the Lower Hel- 

 derherg, Albany and Schoharie counties. 



Strophomena eadiata. 



Strophomena ( Strophodonta) PUNCTULIFERA. 

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



Strophomena punctulifera, Conead : Vanuxem'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 ; sides somewhat 



