NIAGARA FALLS AND VICINITY 1 93 



median septum in the brachial valve, which divides posteriorly, so 

 far as to form an elongate cavity, which does not extend to the bot- 

 tom of the valve. No cardinal process. In the pedicle valve slen- 

 der vertical lamellae support the teeth. 



Camarotoeehia obtusiplicata Hall (Fig. 106). Atrypa ob- 

 tusiplicata Hall (1852. Pal. N. Y. 2:279, P 1 - 58, fig- 2a-h) 



Distinguishing characters. Gibbous, subspheroidal form; strongly 

 convex brachial, and flatter pedicle valve; deep sinus of pedicle 



Fig. 106 Camarotoeehia obtusiplicata 



A-alve with three plications (rarely four) ; depressed incurved beak of 

 pedicle valve; simple, obtusely rounded or flattened plications; faint 

 •concentric striae; strongly emarginate front. 



Found in the lower part of the lower Rochester shales at Niagara. 

 Also in the shales and limestones at Lockport (Hall). 



Camarotoeehia ( ?) neglecta Hall (Fig. 107). Atrypa 

 neglecta Hall (1852. Pal. N. Y. 2:70, 274, pi. 23 and 57) 



Distinguishing characters. Convex 

 valves, brachial valve deepest, sides ^jm$&& 

 sloping abruptly to the beak; strongly *<\.v,'< -' 

 defined sinus and fold, in adult individ- , |N 



ual, the former with three, the latter V,- 



with four plications; profound frontal 

 •emargination; plications rounded. •:.- 1 |k $ ' '• ' , 



Found in the lower Clinton limestone 



. _- . , . Fig. 107 Camarotoeehia (?) neglecta 



in the Clinton lenses and in the upper 



part of the lower and the middle Rochester shales at Niagara. 

 Also more rarely in the upper shales. Found also at Lockport and 

 elsewhere (Hall). 



Camarotoeehia acinus Hall (Fig. 108). Rhynchonella 

 acinus Hall (N. Y. state mus. not. hist. 28th an. reft, p. 163, 

 pi. 26) 



Distinguishing characters. Small size; longitudinally ovate form, 

 narrowing toward beak, truncate in front; subequally convex valves; 



