PLATE IV. 



Page 



Figs. 1 to lb. Prodiitus ior.\ 364 



A latge dov.sal \alve from the Rico formation. 

 Fig. I. Specimen seen from above, 

 la. Posterior view, 

 lb. Side view. 

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



Figs. 2 and 2a. Productus cor a 364 



A large dorsal valve from the Hermosa formation. A specimen in which a number of 

 conformable shelly layers are seen, possibly representing parts of several superposed 

 individuals. 

 Fig. 2. Specimen seen from above. The stria? are represented as somewhat too coarse 

 in this figure. 

 2a. Side view. The stria' in this figure are shown in their natural relation to the 

 size of the shell. 

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



Figs. 3 and 3a. Productus cora 364 



Another ventral valve from the Hermosa formation, more coarsely and regularly striated 



than the last. It is somewhat crushed by pressure. 

 Fig. 3. Specimen seen from above. The figure shows the anterior end of the specimen 

 tilted too far downward. 

 .Sa. Side view of the same. 

 Hermosa formation: Bear Creek, Durango quadrangle (station 2213). 



Figs. 4 and 41i. Productus cora 364 



A \entral valve of a small, finely striated variety, probably considerably broken in its 



anterior portion. 

 Fig. 4. Specimen seen from above. 

 4a. Posterior view. 

 4b. Side view. 

 Hermosa formation: Big Percent Creek, Durango quadrangle (station 2300). 

 494 



