PLATE III. 



PAGE. 



Figs. 1-2. Orthoceras nuntium Hall 425 



1. View of a lar<re individual of this species from the white cherty layers of the for- 

 mation near Dublin, Ohio, showing the general features of the shell, the figure 

 being cut to accommodate the length of the plate. The lower portion of the 

 short section represents the form of the septum at about that position, the 

 shell having been broken near that point. 



'2. Enlargement of the surface from the lower part of the shell. 



Figs. 3-4. Macrocheilus priscus Whitf. ; 424 



3 and 4. View of the aperture showing the straight columella, slightly imperfect 

 at the lower end, and a back view of the same specimen, both enlarged to two 

 diameters. 



Fig. 5. Loxonema parvulum Whitf 424 



5. View of a very perfect specimen enlarged four times. 



Figs. 6-8. Platyceras soualodens Whitf 423 



6-S. Lateral and vertical views of the specimen described, the latter showing the 

 form of t e base. 



Fig. 9. Gomphoceras amphora Whitf 428 



9. View of the upper part of a specimen showing the deep sinus of the aperture 

 and the crowding of the septa in the upper part. 



Fig. 10. Dentalium Martini Whitf 423 



10. View of a specimen retaining the shell and preserving nearly the entire length. 



