54 Pelecypods of the Bowden Fauna [252 



fauna indicates distinctly sub-tropical conditions. Berry 13 

 has shown that the Alum Bluff flora is sub-tropical or very 

 warm temperate and according to Dall 14 the Oak Grove fauna 

 indicates a slight lowering of temperature. Above the Alum 

 Bluff formation is a sharp break that has been seized upon as 

 a convenient location for the division between the Oliocene 

 and Miocene. Though the succeeding Miocene faunas of 

 Florida are imperfectly known they unquestionably indicate 

 a more temperate f acies 15 and occupy a position near the 

 middle of the Miocene series of Virginia and the Carolinas. 

 The Pliocene Caloosahatchie formation of Florida has yielded 

 a rich sub-tropical fauna. 



The profound hiatus in the Floridian succession is par- 

 tially bridged by the Miocene deposits of Virginia and the 

 Carolinas. According to Berry 16 the Calvert formation, 

 which is the oldest, is middle Miocene, probably Tortonian. 

 The only faunas of this region that present a warm-water 

 f acies are those of the late Miocene Duplin and the succeeding 

 Pliocene Waccamaw, both of which are warm temperate rather 

 than sub-tropical. It is apparent that an attempt to compare 

 a mid-Tertiary Antillean fauna with the faunas of Florida is 

 seriously hampered by the absence of any tropical or sub- 

 tropical Miocene faunas on the mainland. Furthermore, in 

 order to make comparisons with any warm-water Miocene 

 fauna of the Atlantic Coast it is necessary to resort to the 

 geographically distant warm temperate Duplin fauna. In 

 Florida the only post- Alum Bluff marine assemblage that 

 flourished under conditions in any manner comparable to 

 those of an Antillean fauna is the sub-tropical Pliocene 

 Caloosahatchie fauna, which is appreciably younger than the 

 slightly more temperate Waccamaw fauna. 



"Berry, E. W., U. S. Geol. Survey Prof., Paper 98-E, pp. 43-44, 

 1916. 



"Ball, W. H., loo. tit., pp. 1549, 1581, 1588-1589, 1903. 

 15 Dall, W. H., loc. tit., pp. 1549, 1589, 1594, 1903. 

 "Berry, E. W., U. S. Geol. Survey Prof., Paper 98-F, p. 66, 1916. 



