APPALACHIAN AND WHITE MOUNTAIN WATERSHEDS. 19 



usually impracticable. If sluiced out of the highest reservoir, it 



fathers iti the next below, and so on tlu-ough whatever system may 

 ave been developed. If, perchance, it should pass the last reservoir, 

 the silt is then free for deposit in the navigable stretches of the stream. 

 Regardless of whether there are reservoirs, the ultimate deposit of 

 the detritus is in the navigable sections, whence its removal can be 

 accomplished only by a steam dredge at the expense of the Govern- 

 ment. 



In the degree that the forests are damaged on the high watersheds, 

 then, inevitable damage results to water power and navigation 

 through increased extremes of high and low water and through vast 

 deposits of gravel, sand, and silt in the stream channels and in any 

 rersevoir wmch may have been constructed. 



CONDITIONS IN THE SOUTHERN APPALACHIAN MOUNTAINS. 



The Southern Appalachian Mountains contain approximately 

 9,900,000 acres, having an elevation above 2,500 feet. 



The Blue Ridge and Great Smoky Mountains consist of an elevated 

 plateau walled in on its western margin by a higher mountain range 

 and with numerous short ranges projecting above its general surface. 

 In one of these, the Black ^fountains. Mount Mitchell rises to 6,711 

 feet, the highest altitude east of the Rocky Mountains. The eastern 

 edge of the plateau is formed partly by peaks rising above the general 

 surface and partly by an abrupt descent that forms an escarpment 

 overlooking the Piedmont Plateau. Over 40 peaks, including approx- 

 imately 6,400 acres, have an altitude of over 6,000 feet, and 54,000 

 acres are above 5,000 feet. The ridges of these mountains are 

 rounded, the slopes precipitous, and the valleys deep cut and narrow. 

 In Virginia the Blue Ridge narrows to a single range of a few miles 

 width, but retains its characteristic topography. It crosses the 

 Potomac River at Harpers Ferry, extends through the State of 

 Maryland, and merges mto the Allegheny Mountains in southern 

 Pennsylvania. 



The Allegheny Mountains extend southward from Pennsylvania 

 and form the mountainous part of West Virginia and that portion of 

 Virginia Ijring near the West Virginia boundary. The highest peak 

 of the Alleghenies is Spruce Knob, in Pendleton County, W. Va., 4,860 

 feet. 



The Cumberland Mountains are simply the extension of the 

 Alleghenies and are considered to begin at the northeast boundary of 

 Kentucky. From this line they extend southwest through Ken- 

 tucky, extreme western Virginia, Tennessee, and into northern 

 Alabama. The Cumberlands are of less elevation than the Alle- 

 ghenies. Their highest peak is Big Black Mountain, in Harlan County, 

 Ky., which has a height of 4,100 reet. 



EBOSION. 



The greater part of the Southern Appalachian region is underlain 

 by rocks that weather into soils which are easity eroded when exposed 

 on deforested slopes. Erosion varies in character on account of the 

 diiferent kinds of soil. In some places the entire surface rapidly 

 wears away, each freshet removing a thin layer, so that the fertile 

 soil is soon exhausted. The field is at last worn out and abandoned. 



