FREE INSTITUTE OF SCIENCE 



39 



THE LIFE FEATURES OF THE COASTAL PLAIN AND THE PIEDMONT 



mous area of the old continent (the Mississippi-Missouri-Ohio drainage basins) 

 was probably not less than two million years, and the rivers on the eastern 

 slope of Appalachia were wearing down their basins at the same time and 

 adding to the formation of the Atlantic Coastal Plain. Professor Edward W. 

 Berry has shown that during the Lower Eocene time the shores of the "Miss- 

 issippi Gulf" were covered by a luxuriant vegetation of tropical forms allied 

 to those of existing families, and even genera, in other parts of the world.* 



With the gradual lowering of the temperature, due to secular changes in 

 climate and the appearance of glacial conditions in the north, a warm temperate 

 flora must have gradually taken the place of the earlier tropical types, spreading 

 over the lands of recently emerged lagoon bottoms. It is with this later forest 

 that our interest chiefly is concerned. 



The northern hardwood forest is more or less typical of the so-caUed 

 "transition zone" of Merriam, and is the characteristic woodland of Appalachia, 

 extending over New England, the greater portion of the' Alleghany Plateau, 

 and the Piedmont of the middle Atlantic slope. It probably originated in 

 post-Pleistocene time, after the recession of the glacial ice and under existing 

 climatic conditions. Among conifers the white pine and the hemlock cover 

 wide areas, the former prevailing especially in sandy soils, while among the 

 chief deciduous types are the beech, the birches, several species of maple, the 

 elms, and the hnden or basswood. To the north this forest gradually gives way 

 to the great boreal coniferous zone of spruce, fir, and tamarack, mingled with 

 birches and aspens. From the lower Delaware southward, the Piedmont and 

 the contiguous border of the Coastal Plain are covered by a woodland of very 

 different character. This forest reaches its maximum development in the 

 central region west of the AUeghanies and extends in a narrow belt around the 

 southern end of the highland country. It is essentially a forest of rich and deep 

 alluvial soils and is remarkable for the great variety of trees. Among these 

 are many different kinds of oaks, several species of hickory, the buckeyes and 

 the tuhp tree, besides numerous other forms, as the chestnut, ash, and a variety 

 of underwoods. Along its southern and eastern borders these tree types are 

 mingled with others of decidedly Coastal Plain distribution, notably the liquid- 

 ambar or sweet-gum and the black gums or tupelos. On Sargent's map this 

 woodland appears as the Interior Hardwood Forest. The wide stretches of 

 Tertiary sands that form the seaward border of the Atlantic and Gulf coastal 



* Berry, Edw. W.: "The Mississippi Gulf Three Million Years Ago." Scientific Monthly, 

 1917, 4. 274. 



