104 TRANSACTIONS OF THE WAGNER FREE 



of the Caloosahatchie leaves no doubt as to the Pliocene age of the 

 latter. 



The exact position in the Pliocene series which the Caloosahatchie 

 deposits occupy, gauged by the standard of classification adopted by 

 European geologists, cannot be readily determined, owing to the very 

 limited number of forms which appear to be common to both sides of the 

 Atlantic. In the percentage of living forms the formation stands nearest 

 to the Antwerp (Black) Crag, the Diestian of the Belgian geologists and 

 to horizon III of the Bolognese Apennines, in which the proportion of 

 living to extinct forms, as determined by Foresti, is somewhat above 43 

 per cent, (vide Fuchs, Die Gtiedenatg ttcr Tertiarbildungen am Nordab- 

 hange der Apenninen von Ancona bis Bologna, Sitzungsb. d. k. Akad. 

 Wissensch., Lxxi, p. 177, Vienna, 1875 ; Heilprin, Contributions to the 

 Tertiary Geology and Paleontology of the United States, p. 64, 1884). 

 This horizon constitutes the base of the Italian Pliocene series (Astian) 

 according to those geologists who, like Capellini, recognize in the lower 

 sub-Apennine deposits a transition formation (Mio-Pliocene ; Messinian, in 

 part, of Meyer) uniting the Miocene with the Pliocene. The relation held 

 by the " Floridian " formation to the deposits of next oldest date occurring 

 in the eastern United States is almost precisely similar to that which 

 obtains in the case of the Bolognese Apennines. Thus, the "Carolinian" 

 formation, which until the discovery of the South Floridian bed just 

 referred to was considered to represent the newest stage of the Atlantic 

 Tertiary series, occupies a position analogous to the Mio-Pliocene of Capel- 

 lini. In its upper member, which comprises the beds occurring in South 

 Carolina, the proportion of living to extinct molluscan forms is, as I have 

 elsewhere shown,* from 35-38 per cent., and I have indicated that while 

 both stratigraphically and faunally this series is more nearly Miocene 

 than Pliocene, it yet might be considered to occupy a position intermedi- 

 ate between the two. In the upper member of Capellini's Mio-Pliocene, 

 Foresti's horizon II, the percentage of living forms is 38.8. The " Flori- 

 dian " formation may thus be safely considered to represent the base of the 

 true Pliocene. The percentage of recent forms in the oldest of the British 

 Crag series, is, according to Lyell, upwards of sixty. 



* Contributions to the Tertiary Geology and Paleontology of the United States, p. 62. 



