204 



NEW YORK STATE MUSEUM 



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. 1 1 :367,. 



pi. 22) 



Distinguishing characters. Ventricose,, 

 elongate; well marked sinus in both valves; 

 lines of growth and prominent wrinkles 



Fig. 128 Whitfieldella sulcata x 1>^ , , .... . . 



and changes m 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 Fig. 129 wmtfleideiia 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. BuL 

 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 

 county (N. Y.) 



Pig. 130 Whitfieldella laevis x 1^ 



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. 23); A t r y p a. 

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



