EXPLANATION OF PLATE CIV. 



MORTONICERAS DELAWARENSIS (Morton), p. 837 



1-3. Lateral, ventral and dorsal views of an incomplete internal 

 cast. 



Merchantville clay-marl; Lenola, (163). 

 4-5. Lateral and dorsal views of the type specimen. 

 Merchantville clay-marl. 



PLACENTICERAS PLACENTA (DeKay ) , p. 830 



6. Lateral view of an incomplete internal cast of an immature 

 specimen. 



Merchantville clay-marl; Lenola, (163). 



PLACENTICERAS TELIFER (Morton) , , p. 832 



7-8. Views of two fragments used by Morton in his descrip- 

 tion of the species. 



Locality not known. 



1092 



