304 BERRY— TERTIARY FLORAS OF THE [April 21, 



It is the chronologic and ecologic aspects upon which I wish to 

 dwell in the present connection. 



The paleobotanical record of the Atlantic and Gulf coastal plain 

 furnishes a history which extends back as I have just mentioned 

 beyond the oldest known angiosperm to a time (Lower Cretaceous) 

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

 and those interesting cycadophytes (Cycadcoidca) whose trunks are 

 sometimes preserved with such marvelous perfection that the out- 

 lines 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 upptM* 

 Cretaceous floras are well represented in the coastal plain from 

 Marthas Vineyard to Texas. They extended northward to Green- 

 land and southward 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 con- 

 sideration of the succeeding Eocene stage of plant evolution. In 

 this as in subsequent times the chief emphasis will be laid upon that 

 section known as the embayment or old Mississippi Gulf, although 

 where the record is more complete in other parts of the coastal plain 

 I will not hesitate to use it. 



Basal Eocene. 



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

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

 sudden expansion and evolution of modern types of mammals and 

 plants after a long antecedent Cretaceous development. The floras 

 become thoroughly modernized as compared with those which pre- 

 ceded them, although they are still very different in their general 

 facies and distribution from those of the present. 



In the earliest stage of the Eocene known as the Midway, the 

 relations of sea and land in the Gulf area differed in only minor par- 

 ticulars from that of the late Cretaceous. The waters of the Missis- 



