Geographie Character: Central Division. 105 
central mountain groups and intermontane valley'). — The Blue Ridge may 
be regarded as forming the extreme eastern range of the Appalachian Moun- 
tains, carrying the main divide between the Atlantic and Gulf drainage. It 
reaches the greatest height in the southern states in Grandfather Mountain, 
with an altitude of 3964 feet (1817 m). The most striking topographic feature 
of the Blue Ridge is the great difference in slopes on its opposite sides, for 
it is steep on the eastern and gradual on the western slopes. The eastern 
Monadnocks’) in the south form several groups of mountains along the 
extreme eastern border of the mountain belt, which have been more or less 
completely isolated by the erosion of eastward-flowing streams. The Unaka 
range may be divided into a northern and southern division. The northern 
division unites in the region of Grandfather Mountain with the Blue Ridge. 
Compared with the Blue Ridge, the Unaka range reaches a considerably greater 
average altitude. Not only are these mountains higher, but their slopes are 
steeper, and their outlines more angular and rugged. 
From a commanding position somewhere on the Unaka range, there may 
be seen stretching to the east and south a confused aggregation of peaks, 
ridges and domes. The cultivated valleys are generally hidden from view, and 
except for an occassional clearing and the grassy “balds” on a few of the 
higher domes, the whole region is covered by a forest mantle. The: interior 
mountains rise to considerable elevations.. A large number of summits reach 
altitudes between 4000 and 5000 feet (1200 and 1520 m) and a few culminate 
above 6000 feet (1830 m). The Black Mountains contain the highest peaks 
of the Appalachian Mountains, culminating in Mount Mitchell, 6711 feet 
(2045 m), 425 feet (129 m) higher than Mount Washington. Between these 
groups and forming a sort of platform above which they rise are many broad 
valleys, commonest toward the head of the streams. Only the smaller streams 
are flowing at the level of these valleys. Down stream toward the northwest, 
the broad valleys are found to be more and more deeply cut, until they occupy 
deep narrow gorges. 
The history of the Appalachian region, as far as it concerns this book 
begins with the Cretaceous period. At least two great cycles of erosion are 
recorded in the southern Appalachians, in which the surface of an old con- 
tinent was worn down from a considerable altitude nearly to base level. 
Shortly after the close of the Carboniferous period the entire Appalachian 
province was finally lifted above sea level, and its subsequent history is recorded 
in the land forms. Following this uplift was a long period, during which the 
region was subjected to the physiographic processes constituting gradation. 
Finally, toward the close of the Cretaceous period, the whole province was 
reduced to a nearly featureless plain, relieved only by a few groups of hills, 
where the highest mountains now stand. After the processes of base leveling 
ı) Hayes, C. Wırıs: The Southern Appalachians. National Geographic Magazine I: 319. 
2) Monadnocks is a name applied to a peculiar type of rounded hills. 
