196 



adductor impressions are divided above by a rounded ridge, 

 which supports the quadrilobed cardinal process. 



■->-n»f»=*H 





Fig. 99. sfnqiliruilnitta concava. Lateral and ilwisal vit-us Df a complete specimen, 

 showing depth bi pedicle valve and hinge areas of both valves : side and front view of 

 interior of brachial valve, shovs-ing depth, muscular impressions, and cardinal process : 

 also the socket and the crenulations on the hinge area (from HallJ. 



Found in the Encrinal limestone, on the Lake Shore (rare) ; 

 in the Demissa bed, at Section 5 (common); between the 

 Trilobite and Pleurodictyum beds (common). 



Stkopheodoxta (Leptostijophia) pekplaxa. Conrad. 

 (Fig. 100.) (Pal. N. Y., Vol. IV., ]j. 98, Pis., XL, XII., 

 XVIL, XIX.) 



