PLATE XXVIII. 



PAGE. 

 Fig. 1. Orthoceras "Winchellti 5L2 



Fig. 2. PHRAGMOCERAS WaLCHU. - 511 



2 a. Side view of an imperfect internal cast, distorted by accidental pressure ; reduced to 



half the Datural diameter. 

 2 b. Another view of same. 



Fig. 3. A.VICULOPECTEN UmONEN'SIS 511 



View of a left valve, natural size. 



