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1gtol BERRY—EOCENE FLORA IN GEORGIA 205 
Certain rather definite climatic deductions appear to be justi- 
fiable from the foregoing facts. None of the modern representa- 
tives of this eocene strand flora flourish north of the winter iso- 
therm of about 50° F., and the majority do not occur north of the 
winter isotherm of 60° F. None of the fossil forms, except possibly 
the Potamogeton, the modern species of which range over a great 
many degrees of latitude, or the Castanea, which likewise has a wide 
range, would be expected to occur outside of the areas where the 
modern subtropical rain forests are developed. We would expect 
the Claiborne climate in the area under discussion, at least at low 
elevations along the coast and in proximity to the eocene gulf 
stream, to have been uniformly humid with an abundant and 
evenly distributed rainfall. The temperature would have been 
uniform, not necessarily extremely hot, and any degree of winter 
cold would have been fatal. 
These considerations are in a large measure corroborated by 
what we find to have been the conditions in Europe at this time. 
It is well known that the middle eocene floras of Europe show 
many tropical characters absent in the earlier Eocene. These 
first become marked in the fruits from the London clays and the 
_ leaves from Alum Bay and in homotaxial deposits on the continent, 
and while it was once the fashion to see Australian -affinities in 
these floras, they show closer affinities with the modern floras of 
Malaysia and tropical America. The accompanying sketch map 
(fig. 1) will bring this out very well. It shows the area of distribu- 
tion of the modern genus Nipa and the eocene genus Nipadites, 
which is indistinguishable from the modern Nipa. The latter has 
a single species inhabiting the tidal waters of the Indian Ocean, 
ranging from India through the Malay Archipelago to the Philip- 
pines, and vying with the mangroves for possession of the tidal flats. 
It produces clusters of large floating fruits, and it is exactly similar 
in both form and structure to the fossil fruits which form the basis 
for the genus Nipadites. As the map shows, these tropical or 
subtropical floras ranged northward in Europe at this time to 
southern England, or to about the latitude of Newfoundland on 
this continent, and these eocene Nipa swamps furnished a congenial 
__ habitat for one or more species of Acrostichum closely allied to that 
