Freshwater Fish Zoogeography 
Fig. 4. Early Pliocene high-sea stand in Florida, Georgia and South Carolina 
(ca. 30 m above present mean sea level). Heavy solid line bordering continental 
landmass indicates Cody Scarp. Open area separating mainland from offshore 
islands indicates position of Suwannee Straits. From Swift et al. (1986). 
<5 13 C records, respectively (Cavelier et al. 1981, Prothero 1985). These 
events apparently resulted from movement of the Antarctic plate and 
the concomitant increased isolation of the Antarctic continent, which in 
turn would have caused increased development of the circum-Antarctic 
current and resulting refrigeration of the continent (Kennett et al. 1972, 
Prothero 1985). Lowered sea levels also tended to accelerate the ero- 
sion 1 processes of the overlying clastic deposits and of the underlying 
limestone substrate in Florida by increasing the speed of percolation of 
surface water through the strata. This is thought to have reduced the 
density of the carbonate rocks exposed near the surface, thus causing 
