sanrls, or "between the Ohipola and the ITioeene" (1). later (£) 

 the faima was given a similar position - hetv/een the Ohipola. 

 Oak '^'-rove. 



(1). Dall, \'i. H., Trans. ,;agner Free Inst. Sci., Philadelphia, 

 ■vol. 3, pt. 5, p. 1582, 19 05. 



(2). DaJl, '. U., Bull. U. 3. Tat. ::us., no. 90, p. 8, 1915. 



Almost 7C per rent of the 3ov;den pelecypods are pec- 

 uli<'ir and 18 wpec'ec, 9 oerjcer-t, persist to the l-'iecent. -he 

 largest assemblage of forms fomid elsewhere is the group of 54 

 species that are known to occur in Santo Domingo; the largest 

 nurnher in common v;ith any horizon in the Floridian succecsion 

 i' --he 15 Ohipolan species, followed hj: 9 '.vith the Oaloosahatchie 

 and 7 with the Temps, and also the Oak Grove. The actiial num- 

 bers are of little significance, since a slight chaiige in the 

 definition of specific lines would have a decidec! effect; uij^e- 

 over^ as the distribiitional list indicates,, much is contingent 

 u"Don the facie s of a fauna at a certa'n horizon, especially as 

 to whether it is tropicsl, s^fotropical or temperate, tixi'.'i al;jo llo- 

 on the extent to which a fauna has been studied. 



The ^lorid ian Tertiary succession, which must be con- 

 sidered the ;jja--aard for the determination of the age of an 

 .'mtillean fauiia, i; ;'nLfortUi:ately incomplete. The Upper Oligo- 



