PLATE VII. 



Page. 



Figs. 1 to lb. Semixul.\ .subtilita 40.3 



A slightly unsymmetrical specimen from the lowest Upper Carboniferous horizon of the 



San Juan region. Eepresented by the figures as somewhat enlarged. 

 Fig. 1. Dorsal view, 

 la. Side view, 

 lb. Anterior view. 

 Hermosa formation: Bear Creek, Durango quadrangle (station 2214). 



Figs. 2 and 2a. Seminula subtilita 40.3 



A small and presumably immature specimen from the same locality and horizon as the 



foregoing. 

 Fig. 2. Dorsal view. 

 2a. Front view. 

 Hermosa formation: Bear Creek, Durango quadrangle (station 2214). 



Figs. 3 .\nd 3a. Seminula subtilita 403 



A large and characteristic specimen. 

 Fig. 3. Dorsal view. 

 3a. Side view. 

 Hermosa formation: Hermosa Creek, Durango quadrangle (station 2239). 



Fig. 4. Seminula subtilita 403 



A small and somewhat peculiar specimen belonging to this species. 



Dorsal ^dew. 



Hermosa formation: Cliff south of Carson Creek, Durango quadrangle (station 2211). 



Fig. 5. Seminula subtilita 403 



A slightly unsymmetrical specimen of smaller size than the original of fig. 3. 



Dorsal view. 



Hermosa formation: Hermosa Creek, Durango quadrangle (station 2239). 



Fig. 6. Seminula subtilita 403 



A specimen somewhat similar to the original of fig. 4, but a trifle larger. 



Dorsal view. 



Hermosa formation: Animas River, Durango quadrangle (station 2246). 



Figs. 7 and 7a. Seminula subtilita. 403 



kn unusually gibbous specimen. 

 Fig. 7. Dorsal view. 

 7a. Side view. 

 Hermosa formation: Lower end of Animas Park ( station 2243) . 

 .504 



