NIAGARA FALLS AND VICINITY l8l 



Stropheodonta corrugata (Conrad) (Fig. 85) (Hall. 1852. 

 Pal. N. 7.2:59, pi. 21) 



Distinzuishin(: characters. Semioval, nearly flat; small, acute 



lateral extensions of hinge; fine, prominent striae sometimes bifur- 





Fig. 85 Stropheodonta coiTugata; with surface enlarged 



eating or alternating with finer ones; oblique folds on hinge 

 margin. 



Found in the Clinton limestone (?) and the Clinton lenses at Ni- 

 agara. Rare. 



Stropheodonta profunda Hall (Fig. 86) (1852. Pal. N. Y. 

 2:61, pi 21) 



Distinguishing characters. Large, semioval, much wider than 

 high; auriculate hinge; profoundly concave brachial valve; abruptly 



Fig. 86 Stropheodonta profunda with enlargement of striae 



'deflected margins; fine, unequal surface striae; papillose or punctate 

 interior. 



Found in the lower and upper Clinton limestone at Niagara. Also 

 in the latter bed at Lockport (Hall). 



