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TERTIARY FAUNA OF FLORIDA ^ 



the surface of the Vicksburg limestone from which the Upper OUgocene marl 

 has been dissolved away. It is the " leit fossil" of the Grand Gulf beds, 

 though not confined to them, and occurs in the single meagerly fossiliferous 

 bed below the Altamaha grits. The specimens are usually in poor condition 

 superficially, having the exterior and often the interior vermiculately eroded. 

 It occurs but rarely in the true Miocene, where it seems to become modified 

 into the early t\'pe of 0. I'irgimca, which is not improbably its direct de- 

 scendant. In old Post-Pliocene beds or oyster reefs it is not uncommon to 

 find enormously thickened senile specimens of 0. virgiiiica which present 

 many of the features of the Oligocene 0. georgiana. 



Ostrea haitensis Sowerby. 



O. haitensis Sby., Quart. Joiirn. Geol. Soc, vi., p. 53, 1850. 



O. //(n'A7;.«i' Gabb, Trans. Am. Phil. Soc, 1873, p. 257. 



O. /'(V?/!//// Gabb, Pal. Gal., ii., p. 34, pi. 11, fig. 59, pi. 17, fig. 21, 1869. 



O. Heermanni Conr., Proc. Acad. Nat. Sci. Phila., v., p. 267, 1853 ; Pac. R. R. Rep., 



v., p. 326, 1855. 

 O. vespertina Conr., Pac. R. R. Rep., v., p. 325, pi. 5, figs. 36-8, 1855 ; Gabb, Pal. 



Gal., ii., p. 107, 1869. (Young shell.) 

 O. iiirginica Guppy, Quart. Journ. Geol. Soc, xxii., p. 577 ; not of Gmelin. 

 O. %ii}-ginica var. californica Marcou, Geol. N. Am., 185S. 



Oligocene of Haiti, of the Bowden marl of Jamaica, of the Chipola 

 beds of Calhoun County, Florida, and of the Oak Grove marl, Santa Rosa 

 County, Florida. 



Miocene (?) of Carrizo Creek, Colorado Desert, California, and of various 

 other localities in California. 



Gabb recognized the identity of his 0. VeatcJiii with the St. Domingo 

 species, and a comparison of Carrizo Creek specimens adds the unfigured O. 

 Heermanni to the list of synonyms. The 0. vespertina was described from 

 young shells from the types in the National Museum, and there can be no 

 question of their identity. It is to be discriminated from its associated 0: 

 Attivoodi, which has a smooth upper valve, by the fact that both valves are 

 similarly plicated. 



Ostrea megodon Hanley. 

 O. megodon Hanley, P. Z. S., 1845, P- '06 ; Reeve, Conch. Icon., Ostrea, pi. .xii., fig. 



24 a-b, 1 87 1. 

 O. galliis Val., Plates of the Voy. Venus, Coq., pi. 21 (no text), 1846. 

 O. eerroscnsis Q-dhh, Pal. Cal., ii., p. 35, pi. 11, fig. 6i, 1869. 



