FREE INSTITUTE OF SCIENCE 



1589 



TERTIARY FAUNA OF FLORIDA 



when the species appear to be undescribed and the whole name when it has been 

 practicable to identify it. In this way the census of the fauna is more com- 

 parable with those of adjacent beds above or below. 



The relation of this fauna to the Chipola is marked, nearly one-third of the 

 species being identical ; and there is also a fair number of species common to 

 Oak Grove, the Tampa silex beds, and Bowden ; but with the immediately 

 succeeding Alum Bluf¥ Miocene the proportion drops sharply to less than one 

 per cent. This sharp change is accompanied by a diminution in the number 

 of species constituting the fauna, in harmony with the theory of a diminished 

 temperature. The exiled fauna, however, regained its lost ground to some 

 extent later on, and pushed a representation of its species as far north as the 

 southern part of New Jersey and to a more marked extent to the Carolinas, 

 where we see that the fauna of the upper or Duplin Miocene, even at the dis- 

 tance of more than five hundred miles to the northward, is more intimately 

 related to the Oak Grove fauna than Oak Grove is to the Alum Blufif Miocene 

 deposited with continuous sedimentation on the same spot. 



LIST OF SPECIES FROM THE OAK GROVE SANDS. 



The great majority of these species come from the typical locality at Oak Grove, 

 Santa Rosa County, Florida, on the Yellow River about six miles south of the Alabama 

 State line. A few have been added from the greenish clayey marl at Rock Bluff, a few 

 miles above Alum Bluff, which is believed to be of the same age as the Oak Grove bed. 

 A letter following the authority for the name indicates that the species is also known 

 from Bowden (B), the Tampa silex bed (S), or the Chipola marl (C). Two or three 

 species are also cited from a depth of about fifteen hundred feet in the Bascom well, near 

 Mobile, Alabama (M), and a few others from the White Beach Oligocene, near Osprey, 

 Florida. 



The gastropods of this list, having been received too late to be included in the body of 

 the text, are only approximately identified, but for the most part seem specifically distinct 

 from the analogous species in the Chipola marl. 



Vaginella sp. (not the Chipola sp.). *Cylichnella bidentata Orbigny?. 



Action sp. (cf. cubensis Gabb). Retusa (cf. sulcata Orbigny). 



Actseon sp. ' Retusa (Cylichnina) quercinensis Dall. 



Ringicula semilimata Dall, C. Volvula (cf. acuta Orbigny). 



Tornatina incisula Dall, C. Atys sp. 



Tornatina persimilis Dall, C. -Terebra (cf. indenta Conrad, Duplin). 



Tornatina crassiplica Dall n. sp. Terebra psilis Dall. 



Tornatina (Coleophysis) chipolana Dall, C. Terebra tantula Conrad, S. 



