196 



adductor impressions are divided above by a rounded ridge, 

 which supports the quadrilobed cardinal process. 



ft 



m 

 ( t 



*i 



Fit;. 99. Stropheodonta concava. Lateral and dorsal views of a complete specimen. 

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



interim' of brachial valve, showing depth, muscular impressions, and cardinal process : 

 also the socket and the rreimlations 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). 



Stropheodonta ( Leptostrophia | perplana. Conrad. 

 (Fig. 100.) (Pal. X. Y., Vol. IV., p. 98, Pis., XI., XII., 

 XVII., XIX.) 



