PLATE XVII. 



Page. 

 PLATYSCHISMA McdOYi 188 



Figs. I, ia, 1 b. Summit, lateral, and basal view of a small specimen. Natural size. 

 Ic. Longitudinal section of a larger shell. 



METOPTOMA ? DEVONICA 195 



Figs. 2, 2 a. Lateral and anterior view of the type specimen. 



PLATYSCHISMA ? AMBIGUUM 



Figs. 3, 3 a. Lateral and summit view of a silicified specimen. 



BEYRICHIA (P) OCCIDENTALIS JU 1 



Fig. 4. Large size left valve, enlarged to four diameters 



4a. Enlargement of a young specimen (l mm ) in length, to show the unisulcate char- 

 acter at this stage of growth, x 12. 



DALMANITES MEEKI 



Fig. 5. View of the glabella of a medium size specimen. 



5 a, 5ft. Dorsal and lateral views of a medium-size and large pygidium. 

 5c. Enlargement of a portion of the surface of 56, to show the punctate chara- 

 of the test. 



BELLEROPHON PERPLEXA 193 



Fig. 6. Transverse section, showing the deep, open umbilicus and flattened whorls. 

 Qa. Dorsal view, showing the,dorsal ridge and the direction of the strhe. 

 G 1). Longitudinal section, showing the closely coiled whorls. 



C YRTOCERAS NfiVADENSIS 20'.\ 



Fig. 7. Lateral view, showing the depth of the chambers and the curvature of the tube. 

 7 a. Ventral view of the same, with the surface stria3 preserved. 



GOMPHOCERAS SUBOVIFORME -Ji i-j 



Fig. 8. Ventral view, showing the chamber of habitation, air-chambers, and a portion of 



the siphuncle exposed by the weathering of the specimen. 

 8 a. Lateral view of the Fame. 



BELLEROPHON COMBBI 193 



Figs. 9, 9a. Lateral and front view, to show the form of the species. 



GOMAIITES DESIDERATUS -J03 



Fig. 10. Lateral view of a specimen preserving a portion of the surface striro on the inner 

 volution. 







