326 BRANSON AND GREGER AMSDEN FORMATION OF WYOMING 



Plate 19. — Fossils p'oni the Amsden Formation 



Pustula gene vieven sis (Weller) 



Figures 1-2. Ventral and side views of a pedicle valve. 



Orthotetes kaskashiensis (McChesney) 



Figure 3. Posterior view of an imperfect specimen. 

 Figure 4. Exterior view of a brachial valve. 



Diaphragmus pliilUpsi (Norwood and Pratten) 

 Figures 5-6. Brachial and pedicle valves. 



OrMculoidea wyomingensis n. sp. 



Figures 7-8. Pedicle and brachial valves of imperfect specimens. 



Bucanopsis or Bellerophon 



Figures 9-10. Two views of an interior cast. 



Microdon cf. oMongus (Hall) 



Figure 11. Internal cast of a specimen referred to this species with some 



doubt. 

 Figure 25. Specimen doubtfully referred to this species. 



Schizophoria swallovi Hall 



Figures 12-13. Anterior and pedicle views of an immature specimen. 



Cleiothyridina hirsuta (Hall) 



Figure 14. Brachial view of conjoined valves of a perfect specimen. 



BuUmorpha canaliculata Hall 



Figure 15. Side view of a specimen with the apical coil missing. 



Phillipsia sp.? 



Figure 16. Dorsal view of an imperfect pygidium. 



Martinia n. sp. 



Figures 17-18. Brachial and lateral views of conjoined valves of a perfect 

 specimen. 



Zaphrentis amsdenensis n. sp. 



Figure 19. Side view of a specimen of average size. 

 Figure 20. View of the calyx (X2). 



Chobtetes'i 



Figures 21-22. Two views of a silicified specimen. 



Paleoneilo amsdeneyisis n. sp. 



Figure 23. Lateral view of a nearly perfect internal mould. 

 Figure 24. Dorsal view of the same specimen. 



Myalina sancti-ludovici Worthen 



Figure 26. Lateral view of a perfect specimen. 



