PLATE XXXVII. 
Pliocene Arcas. 
Fig. 1. Area camuloensis Osmont. California State Mining Bureau. Type. Right 
valve; altitude 89 mm. Fernando formation, lower Pliocene or upper 
Miocene, 1 mile north of Camulos, Ventura County. So far as known this 
species is characteristic of the lower horizon of the Fernando formation. 
Also reported from the Puente Hills. 
Fig. la. End view of same specimen as fig. 1. 
Fig. 16. Portion of surface of same specimen as fig. 1, enlarged, showing nodose ribs. 
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