NIAGARA FALLS AND VICINITY 



203 



Whitfieldella oblata Hall (Fig. 125). Atrypa oblata Hall 

 {1852. Pal. N. Y. 2:9, pi. 4) 



Distinguishing characters. Oblate form, nearly as broad as high; 

 broadest anteriorly; sloping abruptly to the beak; small, well 





Fig. 125 Whitfleldella oblata 



defined beak; nearly equally convex valves; central groove on 

 pedicle valve and slight elevation on brachial valve; surface marked 

 only by lines of growth. 



Found in the upper Medina sandstone at Niagara. Also at 

 Lockport (Hall). 



Whitfieldella intermedia Hall (Fig. 

 126). Atrypa intermedia Hall 

 (1852. Pal. X. Y. 2:77, P 1 - 2 4) 



Distinguishing characters. Obovate; 

 rapidly expanding to front, which is 

 abruptly rounded; length and width 

 nearly equal; convex near beak, flatter 

 toward front; slight frontal sinuosity; 

 faint growth lines. 



Found in the Clinton lenses and 

 lowest Clinton shales at Niagara. Also in the upper Clinton lime- 

 stone at Lockport (Hall). 



Whitfieldella cylindrica Hall (Fig. 127). Atrypa cylin- 

 drica Hall (1852. Pal. N. Y. 2:76, pi. 24) 



Fig. 120 Whitfieldella intermedia 



w 



Fig. 127 Whitfieldella cj lindrica 



Distinguishing characters. Elongate cylindric; strongly convex; 

 nearly as wide as thick; strongly overarching beak of pedicle valve; 



