EXPLANATION OF PLATE VII. 



rage. 

 RlIYNCIIONELLA M YKINA 284 



V Figs. 1-4. Dorsal, ventral, profile, aud front views of a characteristic specimen. 

 5. Ventral valve, showing a variation of form in thp sinus. 1.0/ 'i- ' 



VliUYNCIIONELLA GNATIIOPHORA ? 284 



Fig. 6. View of the ventral Valve referred with doubt to this species. / 2 5 5 * 



/Tekebkatula Augusta 285 



Fig. 7. View of a ventral valVe of the usual form and size. 



8-10. Dorsal, ventral, and profile views of a specimen, enlarged to two diameters. - 



vGkypii^a? Calceola van Nebrascensis ? 286 



Fig. 11. Interior of the larger valve, showing the prevailing form which occurs in the 

 localities mentioned under the description. /;^$ 4 '-- 



vdsTHEA Engelmanni? 285 



Fig. 12. View of an impression of the interior of the attached valve. /X.5-*'^ 



Camptonectes bellistriatus 289 



Fig. 13. View of an imperfect right valve of the size most common among those in the collec- 

 tion. 



AVICULOPECTEN ? (EOMICROTIS) AUGUSTENSIS - 288 



Fig. 14. View of a right or flat valve. 



15. A loft valve from the same specimen of rock. 



16. Enlargement of striie from another individual, preserving the surface. 



^AMPTONECTES PERTENUISTRIATUS 291 



Fig. 17. View of a right valve of the species, enlarged to twice the natural size ; the posterior 

 wing restored in outline. , P52S> 



^/Camptonectes extenuatus ' 290 



Fig. 18. A right valve, natural size. | ;2. 55 2- 



Natica? Lelia , 298 



Figs. 19-21. Three views of an individual of the ordinary size eularged. The lino near i\g. 20 

 shows the natural height. 



Triggnia quadrangularis 293 



Fig. 22. View of an imperfect right valve, enlarged to twice the natural size. The outline 

 would seem to have been considerably extended posteriorly./ ^5 3 7 



' Lima (Plagiostoma) occidentalis 292 



Fig. 23. View of a left valve, slightly restored at the beak aud hinge, as also on the umbono 



) 



^^UMICROTIS curta ? 289 



Fig. 24. View of a left valve, enlarged, showing the alternate size of the radii. '^ f ' 

 SEProcAnDiA Carditoidea " 296 



V Fig. 25. View of the posterior end of the specimen described. / - 



Septocardia typica 295 



\ 



Fig. 20. Enlarged view of the exterior of a right valve, showing the general form and the 



oruameutatious on the ribs. ' ?-5 3 W 



27. View of the interior of the same valves, showing the hinge-character? as described. 



28. Eularged hinge-line of the left valve. 



29. Cast of a large right valve, enlarged to twice the natural size, to show the posterior 



muscular scar. 



