204 



NEW YORK STATE MUSEUM 



fc'ig. 128 Whitfieldella sulcata x 1]4 



faint mesial depression in pedicle valve; slight frontal sinuosity; fine 

 radiating striae near the front. 



Found in the upper Clinton limestone at 



Lockport (Hall). Probably also at Niagara. 



Whitfieldella sulcata (Vanuxem) (Fig. 



128) (Grabau. Geol. soc. Am. Bui. 11:367, 



pi. 22) 



Distinguishing characters. Ventricose, 

 elongate; well marked sinus in both valves; 

 lines of growth and prominent wrinkles 

 and changes in direction of growth. 

 Found in the Manlius limestone of North Buffalo, etc. 

 Whitfieldella rotundata (Whitfield) (Fig. 

 129) (Grabau. Geol. soc. Am. Bui. 11:368, 

 pi. 22) 



Distinguishing characters. Small, subcir- 

 cular; moderately convex; beak curved at Fi g . 129 wmtneideiia rotundata 

 right angles to plane of contact of valves. 



Found in the Manlius limestone of Erie county (N. Y.) 



Whitfieldella laevis (Whitfield) (Fig. 

 130) (Grabau. Geol. soc. Am. Bui. 

 11:369, pi. 22) 



Distinguishing characters. Small; broad- 

 ly ovoid; moderately gibbous, greatest 

 gibbosity in posterior third; faint mesial 

 depression. 



Found in the Manlius limestone of Erie 



Pig. 130 Whitfieldella laevis x \\& coun f v ("M V ") 



Genus hyattella Hall & Clarke 



[Ety.: proper name] 



(1893. Pal. N. Y. v. 8, pt 2, p. 61) 



Shell similar to Whitfieldella, but compactly subpenta- 

 hedral, and without the median septum in the brachial valve. 



Hyattella congesta (Conrad) (Fig. 131 and 131a). Atrypa 

 congesta Hall (1852. Pal. N. Y. 2:67, pi. 2^); Atrypa 

 quadricostata Hall (Pal. N. Y. 2 :68, pi. 23) 



