﻿3,6 Bulletin 20 114 



Explanation of Plates 



PLATE I. 



Page. 



Spirorbis sp 2 4 



Fig. 1. View of a specimen with much of the shell broken away. 

 Logan, Utah, (x 10) 



Favosites cf . limitaris 2 4 



Fig. 2. View of weathered specimen. Princeton, Mont, (x 1) 



Productella cf . spinulicosta 2 5 



Fig. 3. View of ventral valve. Princeton, Mont, (x 1) 



3a. Exterior of dorsal valve of small individual. Princeton, 

 Mont, (x 2) 



Atrypa hystrix var. occidentalis (H) 2 9 



Fig. 4. A fragmentary ventral valve. Princeton, Mont, (x 1*) . 



Atrypa spinosa var. montanensis , n. var 2 § 



Fig. 5. Dorsal view. Livingston, Mont, (x 1) 



5a. Ventral view of same individual; shell partially exfoliated. • 

 5b. Side view of another specimen. Livingston, Mont, (x 1) 

 5c. View of a fragmentarv dorsal valve. Princeton, Mont, 

 (xi) 



Atrypa reticularis 2 § 



Fig. 6. A front view. Flat Iron Mountain, Lewis and Clark 

 Forest Reserve, Mont. (4803) (x 1) 



Atrypa missouriensis 2 9 



Fig. 7. Dorsal view. Princeton, Mont, (x 2) 

 7a. A profile view of the same individual. 



7b. A dorsal view of an exfoliated shell. Livingston, Mont, 

 (xi) 



Schuchertella extensus, n. sp 2 6 



Fig. 8. Dorsal view of the type specimen. Sixteen P. 0., Mont. 

 (xi) 

 8a. Ventral view of the same individual. 

 8b. A side profile view of 8a. 



Hypothyris (?) globularis n. sp 2 7 



Fig. 9. Dorsal view, Princeton, Mont., 16 C. (x 2) 

 9a. Front view of the same individual. 

 9b. Side view of 9a. 



