A STUDY OF THE TERTIARY FLORAS OF THE 

 ATLANTIC AND GULF COASTAL PLAIN.^ 



By EDWARD W. BERRY. 



(Read April si, IQII.) 



Introductory. 



The observations recorded in the following pages may be said 

 to represent a preliminary sketch of a small chapter in the study of 

 the South Atlantic and Gulf Coastal plain undertaken by the United 

 States Geological Survey in cooperation with the various state sur- 

 veys under the direction of Dr. T. W. \^aughan. 



Neither geologist nor biologist fully appreciates the magnitude, 

 complexity or uniqueness of the coastal plain of the southeastern 

 United States. The present coast line, a boundary first recognized 

 by the aborigines and early explorers and so emphasized by geog- 

 raphers, is from the standpoint of the student of geologic history a 

 continually shifting demarcation which does not, nor perhaps never, 

 marked the seaward limit of the physiographic unit known as the 

 Coastal Plain Province, for the gently sloping land surface continues 

 seaward beneath the waves of the present Atlantic and Gulf waters 

 varying distances up to lOO miles or more and then precipitately de- 

 scends several thousand feet in a few miles, forming the majestic 

 escarpment which is regarded as the continental boundary. In the 

 past the coast line has advanced inland over the present emerged 

 portion of the coastal plain and receded seaward over the present 

 submerged margin, many times. At one time the waves of the Gulf 

 of ]\Iexico broke in southern Illinois, at another they were confined 

 lOO miles south of the present sites of ]\Iobile and New Orleans, 

 600 miles to the southward. 



On the whole, the history of events in Tertiary times has been a 

 progressive adding to the land area of the continent, the most im- 



^ Published with the permission of the director of the United States 

 Geological Survey. 



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