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677 



TERTIARY FAUNA OK FLORIDA 



case that this habit (as in 0. percrassa Conr.) has attained a constancy entitling 

 it to systematic significance. 



Having thus pointed out some of the features which are liable to mislead 

 the student in estimating specific values, we may proceed to consider the 

 species of our Tertiary. 



Ostrea crenulimarginata Gabb. 

 (>. i-i-cnitliinarifiiiata Gabb, Journ. Acad. Nat. Sci. Phila., 2d Sen, iv., p. 398, pi. 68, figs. 



40, 41, 1860. 

 .' (>. licnticiilifcra Conr., Journ. Acad. Nat. Sci. Phila., 2d Ser., iii., p. 330, pi. 34, fig. 18, 



1858. 



(>. prtecompressirostra Harris, Rep. Ark. Geol. Surv., ii., p. 39, 1894. 

 (). tiimidnla Aldr., Rep. Geol. Surv. Ala., p. 242, pi. 14, figs. I, 2, pi. 15, figs. I, 2, 



1894. 



Midway stage of the southern Eocene, from the well at Little Rock, 

 Arkansas; Prairie Creek, Wilcox County, Alabama; and the Chattahoochie 

 River, near the mouth of Pataula Creek, Alabama. 



Conrad's species is described from a specimen too young to show its 

 specific characters ; otherwise it is probably identical with that of Gabb. 



Ostrea pulaskensis Harris. 

 0. pulaskensis Harris, Rep. Ark. Geol. Surv., ii., p. 40, pi. I, fig. 3, 1894. 



Midway horizon, at various points in Arkansas. 



This species is represented in the collection by rather poorly preserved 

 and young material which leaves a suspicion that it is extremely closely allied 

 to 0. tliirsic Gabb, though not sufficient to show their identity. The valves 

 recall the lower valve of 0. subevcrsa, but have no auriculation. 



Ostrea sellseformis Conrad. 



O. scllicfonnis Conr., Fos. Tert. Form., p. 27, pi. 13, fig. 2, 1832 (upper valve). 

 O. radians Conr., loc. fit., fig. I (lower valve). 

 O. divaricata Lea, Contr. Geol., p. 91, pi. 3, fig. 70, 1833. 

 0. si-Hii/ittiii/a Lea, op. cit., p. 90, pi. 3, fig. 69, fide Conrad. 

 O./it/fij'dnnis Conr., Am. Journ. Conch., i., p. 140, pi. xi., fig. I, 1865 ; Proc. Acad. Nat. 



Sci. Phila. for 1863, p. 291. 



('. tini;na-fftis \Vhitficld, Lam. Kar. Clays, p. 223, pi. 29, fig. I, 1885. 

 (). i/itiif<>iii>i<i,-s \Vhitf., loc. cit., fig. 2. 

 O. stfllceformis Conr., Am. Journ. Conch., i., p. 15. 1865 (err. typogr.). 



Eocene of Claiborne, Alabama ; Coffeeville, Alabama ; Coggins Point 

 and City Point, James River, Virginia. 



