THE PIEDMONT REGION. 127 



The elevation of thirty-one points in the Piedmont region, varying 

 from a minimum of 179.5 feet on the granite rocks at the Congaree bridge, 

 below Columbia, to a maximum of 880 feet at Belton, on the Greenville 

 railroad, give a mean elevation above the sea of 590 feet. The mean 

 elevation of the Columbia and Augusta railroad, where it passes along 

 the southern border of the region, is 575 feet. That of the Air Line rail- 

 road in South Carolina, lying to the north of it and almost wholly within 

 the Alpine region, is 910 feet. Between these two lines, therefore, a dis- 

 tance of some ninety miles, there is a general rise of the surface of three 

 hundred and thirty-five feet, or less than four feet to the mile. This is a 

 gentler slope than that of the tertiary plain or low country. The distance 

 from the sea to its northern border being about one hundred miles, and 

 the difference in elevation something more than five hundred feet, or over 

 five feet to the mile. 



The face of the countr}' presents a gently undulating plain, which be- 

 comes more rolling as it approaches the rivers and larger streams, and is 

 finally hilly and broken above the bottoms and narrow, low grounds, 

 through which the numerous water courses find their passage. 



While the general rise in the surface is less than that in the low country, 

 the rise in the beds of the streams, owing to the resistance of the under- 

 lying rocks, which prevent the water from deepening their channels, is 

 much greater. Thus, the elevation above the sea of the lower falls of 

 these rivers is, for the Savannah, 133 feet ; for the Congaree, 135.3 feet; 

 for the Wateree, 133 feet; but where they enter this region from the 

 north, the surface of the water has an elevation above the sea level of 

 403 feet for the Savannah, of 552 feet for the Broad river, and of 514 feet 

 for the Catawba. This gives an average difference of 3G0 feet in about 

 83 miles, or a fall per mile in the Piedmont region of 4| feet, against an 

 average fall in the lower course of these rivers of about 1.2 feet per mile. 

 While this renders the navigation of the upper portions of these rivers 

 difficult, it adds largely to their availability as water powers for moving 

 stationar}^ machinery. 



The Savannah river, on the western boundary of the State, passes 

 through the metamorphic rocks for more than one hundred miles, and 

 although it receives many affluents, and some of them quite large, on its 

 eastern bank, they join at such an acute angle as to make its eastern 

 water shed very narrow — scarcely anywhere exceeding twenty miles 

 in width. To the east, Lynch's river passes through this region for about 

 twelve miles, its western water shed not exceeding five miles. Between 

 these two narrow water sheds in the east and west there is an interval of 

 about one hundred miles. The numerous streams traversing this inter- 

 val belong to one river system, and unite shortly after entering the ter- 



