DESCRIPTION OF PLATE VII CONTINUED. 505 



Page. 

 Fig. 8. Seminula subtilita 403 



A specimen from the highest known Carboniferous horizon in the San Juan region some- 

 what distorted by pressure. 



Dorsal view. 



Rico formation: Scotch Creek, Eico quadrangle (station 2342). 

 Fig. 9. Seminula subtilita 403 



A small specimen of this species. 



Dorsal view. 



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

 Fig. 10. Seminula subtilita 403 



A rotund specimen with fold and sinus less strongly marked than usual. 



Dorsal view. 



Hermosa formation: Sandstone Mountain, Rico quadrangle (station 2216). 

 Figs. 11 and 11a. Dielasma bovidens ? 409 



An immature or not very characteristic representative of the species to which it is doubt- 

 fully referred. 



Fig. 11. Dorsal view. 

 11a. Side view. 



Formation (?): Rock Creek, Elk Mountains. 

 Figs. 12 AND 12a. Hustedia mormoni 411 



A characteristic specimen. 



Fig. 12. Side view. 



12a. Ventral view. 



Maroon formation: Southeast of Italian Peak, Elk Mountain region (station 2280). 

 Fig. 13. Hustedia mormoni 411 



A somewhat smaller specimen than the preceding, slightly distorted by pressure. 



Dorsal view. 



Maroon formation: Southeast of Italian Peak, Elk Mountain region (station 2280). 

 Figs. 14 to 14b. Pugnax utah 412 



A characteristic specimen. 



Fig. 14. Ventral view. 

 14a. Anterior view. 

 14b. Side view. 



Maroon formation: Southeast of Italian Peak, Elk Mountain region (station 2280). 



