PHYSICAL CONDITIONS. 15 



PHYSICAL DESCRIPTION OF THE REGIONS. 



From a geological standpoint, Virginia and the South Atlantic States 

 are divided into several regions. The natural physical divisions result 

 from the geological formations, and hence conform closely to the 

 geological regions in their extent. There are no sharply defined lines 

 of demarcation between these different regions, each one extending 

 by almost imperceptible gradations into the adjoining ones. The 

 general direction in which they extend is parallel to the coast line. 



What may be termed the ''pomological regions" of these States 

 are nearly coincident with the physical regions, and hence they may 

 properly be referred to in the present connection. 



The points wherein the physical and pomological regions do not 

 correspond in location coincide mainly with differences in elevation. 

 The map shown as Plate V indicates the location and extent of the 

 pomological regions as nearly as it is possible to outline them from 

 available data. By studying the contour lines, the approximate 

 elevation and topography of any section within the boundaries of 

 each region can be determined without difficulty. The relief map 

 shown in Plate IV may also be of assistance in studying the topog- 

 raphy of the territory under consideration. 



The three most important divisions or regions which are common 

 to all the States under consideration are called by various terms, 

 but most frequently they are spoken of as the Coastal Plain, the 

 Piedmont, and the Blue Ridge regions. These divisions are variously 

 subdivided by different authors, but it is not necessary to consider 

 them in detail in the present connection. It may be well, however, 

 to note that in the Virginia section the eastern portion of the Pied- 

 mont region is frequently referred to as middle Virginia, thus restrict- 

 ing the Piedmont region to a relatively narrow strip of country 

 adjacent to the Blue Ridge Mountains. There are also two other 

 natural divisions which should be mentioned, one of wmich is known 

 as the Appalachian Valley, while the other includes the Allegheny 

 and Cumberland plateaus. 



The Coastal Plain extends the entire length of the coast line of 

 these States and varies in width from a few miles to 150 or 200 miles 

 at some points. It is generally level, and the greater portion of its 

 surface is but a comparatively few feet above sea level, except along 

 its western limits, where it grades into the Piedmont region; here it 

 reaches an elevation of about 500 feet at some points. 



The section of the map (PL V) indicated by the lighter horizontal 

 hatching (see legend on map) comprises the Coastal Plain and that 

 portion of the Piedmont region which is below 500 feet elevation. In 

 Virginia this includes a considerable section that belongs geologic- 



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