1914-] SOUTHEASTERN NORTH AMERICA. 131 



of fruits and seeds, and in some few cases even flowers are pre- 

 served. 



While the oscillations of the embayment area have been numerous 

 they have been, as I have just mentioned, inconsiderable in amount, 

 only a few hundred feet at most, and the coastal region has tmiformly 

 been one of slight relief. The various floras show an almost com- 

 plete absence of upland types. This is in striking contrast to the 

 European older Tertiary floras. The only large area of the globe 

 which has been thoroughly studied — Europe — was far less stable 

 than this region in Tertiary times and lying much farther toward the 

 pole was subsequently subjected to the rigors of Pleistocene condi- 

 tions whose influence never reached our southern states. 



The paleobotanical record of the Atlantic and Gulf Coastal Plain 

 furnishes a history which extends back as I have just mentioned be- 

 yond the oldest known angiosperms to a time (Lower Cretaceous) 

 when the flora was made up almost entirely of tree-ferns, conifers 

 and those interesting cycadophytes (Cycadeoidea) whose trunks are 

 sometimes preserved with such marvelous perfection that the outlines 

 of the embryos in the ovules can often be made out in detail. Coming 

 a step nearer my present theme, a step of some millions of years 

 from the Lower into the Upper Cretaceous, we find the first great 

 modernization of the floras of the world due to the seemingly sudden 

 evolution of the main types of angiosperms. These Upper Creta- 

 ceous floras are well represented in the Coastal Plain from ^Marthas 

 Vineyard to Texas. They extend northward to Greenland and south- 

 ward to Argentina in South America, and are found to indicate very 

 different physical conditions from those which prevail at the present 

 time. I do not intend, however, to dwell upon the Upper Cretaceous 

 floras in this connection but pass to a consideration of the succeeding 

 Eocene epoch of plant evolution. 



The Eocene as defined by Lyell was marked by the dawn of the 

 recent species of marine mollusca. It is equally well marked by the 

 sudden expansion and evolution of modern types of plants after a 

 long antecedent Cretaceous development. The floras become thor- 

 oughly modernized as compared with those which preceded them, 

 although they are still very different in their general facies and dis- 

 tribution from those of the present. 



