PLATE XXX. 



PAGB 



Fig. 1. Cyrtoceras curtum, M. and W 388 



1 a. Side view of specimen with the smaller extremity broken away, show- 



ing the arching of the surface striae and lip, as well as the position 

 of the siphuncle at 5. 



Fig. 2. GrONIATITES GLOBULOSUS, M. and W 390 



2 a. Dorsal side, of an internal cast, showing the septa. 

 2 b. Lateral view. 



2 c. Diagram of one of the septa. 



Fig. 3. GrONIATITES iowensis, M. and W 392 



?> a. Side view of an internal cast, showing the septa. 



3 b. Profile outline of same. 



3 c. Diagram of the lobes and saddles of a septum, near natural size. 



