PLATE XIV. 



Page. 



PRODUCTUS SHUMARDIANUS.... 129 



Fig. 1. View of the dorsal valve. Natural size. 



PRODUCTUS TRUNCATUS 



Fig. 2. View to show the truncated apex of the ventral valve. Natural size. 



RHYNCHONELLA HORSFORDI 152 



Fig. 3. Ventral view of an average size specimen. See plate xv, fig. 6. 



ATRYPA DESQUAMATA 150 



Fig. 4. View of the ventral valve. 



4 a. Cardinal view to show the small area. Natural size. 



RHYNCHONELLA (L.) SINUATA 158 



Fig. 5. Dorsal view of a characteristic specimen. Natural size. 



ATRYPA RETICULARIS l- r >0 



Figs. 6, 6 a, 6 ft. Ventral, lateral, and dorsal views of the small variety mentioned in the text 

 as characteristic of the Niagara formation. 



RHYNCHONELLA PUGNUS 155 



Figs. 7,7 a. Lateral and ventral views of an average size specimen. 



RHYNCHONELLA DUPLICATA 155 



Fig. 8. Dorsal view of a very striking example of the species. 



RHYNCHONELLA (L.) NEVADENSIS 157 



Figs. 9,9 a, 9fc. Ventral, lateral, and dorsal views of the ordinary type of the species. 



SPIRIFERA PARRYANA 137 



Fig. 10. Ventral view of the only specimen obtained, showing the costse and fine radiating 

 striae. 



SPIRIFERA (M.) UNDIFERA 143 



Figs. 11, 11 a, ft. Dorsal, lateral, and ventral views of a specimen from which most of the 



outer surface is removed. 

 136. Ventral valve with a portion broken away, showing the cast of the muscular 



impression. 

 13 c. Ventral valve of a broad variety of the species, showing the area and small del- 



tidium in place. See plate iii, figs. 3, 3 a, b, 6, 6 a. 



SPIRIFERA (M.) RARICOSTA 135 



Fig. 12. View of the partial cast of the dorsal valve of a small shell. See plate iv, figs. 2, 2 a. 



SPIRIFERA(M.)MAIA 141 



Figs. 13, 13 a. Dorsal and lateral views of an average specimen of the species. See plate 

 iii, figs. 1, 1 a-e. 



SPIRIFERA (M. ) GLABRA, var. NEVADENSIS 139 



Figs. 14, 14 a, 6. Dorsal, lateral, and front views of the largest and most transverse speci- 

 men in the collection. See plate iii, fig. 5. 



PKNTAMERUS (M.) COMIS 159 



Figs. 15, 5 a, 1). Dorsal, lateral, and ventral views of a transverse, smooth specimen. See 

 plate iii, figs. 4, 7, and plate xv, figs. 5, 5o, c. 



