367 



Costa Rica Miocene — Olsson 



195 



Gatun Stage: Hill z, la, Banajia River, typical and va7\ 



suberversa 



Coll. 7, Pumbric Creek {^typical) 

 Coll. 6, Red Cliff Creek {typical) 

 Betey {subreversa) 

 Zone G, Saury {subreversa) 



Genus PTERIA, Scopoli 



Pteria inoniata Gabb Plate 28, figure 9 



Avicula ino-ynata Gabb, 1873, Trans. Amer. Phil. Soc, vol., 15, p. 

 253- 



Pteria inornata Dall, 1898, Trans, Wagner Free Inst, Sci., vol. 3, pt. 

 4, p. 669. 



Pteria ifwrnata Maury, 1817, Bull. Amer. Pal,, vol, 5, p. 345, pi. 26, 

 fig. 14. 



This species is locally common in Costa Rica, but generally 

 difficult to collect because of its thin and fragile shell. Its 

 valves are as high as long, strongly convex and smooth. The 

 anterior ear is of medium size, the posterior much larger and 

 produced. 



It was described as a Miocene fossil from Santo Domingo, 

 but has also been collected at Bowden. 



Uscari formatio7i. Old Harbor. 

 Gatun Stage: Zone j; Red Cliff Creek. 



Genus OSTREA, Linnaeus 



Ostrea megodon Hanley Plate 18, figure I 



Ostrea megodon Hanley, 1845, Proc. Zool. Soc. London, p. 106. 

 cf. Ostrea cerrosensis Gabb, 1869, Geol. Surv. Calif., vol, 2, p. 35, pi, 

 II, fig, 61. 



Ostrea megodon Dall, 1897, Trans. Wagner Free Inst., vol. 3, pt. 4, p. 

 685. 



Ostrea megodon Maury, 1917, Bull. Amer. Pal., vol. 5, p, 347, pi. 34, 

 H- 3- 



