30 
AMERICAN GEOLOGY. 
southern rivers, viz: the Rappahannock at Fredericksburg, 
James river at Richmond, the Roanoke at Weldon, the Tau at 
Rocky Mount, the Neuse six miles east of Raleigh, the Cape 
Fear near Haywood in Chatham county, or at the falls of the 
Buckhorn. Above the falls the rivers are more rapid, but their 
ascent to the base of the Blue ridge is still gentle, though 
rapid at many places. At the base of the crest of the Blue 
ridge their height above the ocean rarely exceeds 500 feet. 
From this point up the ascent on the east side is exceeding 
rapid for five miles. On the west side the slope is again gen¬ 
tle. It appears, therefore, that the slope is on the west side 
towards the Mississippi valley, while the counter slope is on 
the east, and contrary to that which prevails in Pennsylvania 
and New York. 
A remarkable feature in the Atlantic plain, forming part of 
the eastern slope of the Appalachian range, is the country of 
the Pine barrens. These are sandy plains, undulating like a 
sea bottom, and clothed with the long-leaved pine. Although 
of considerable extent, and traversed by rivers and streams, the 
sand, though a marine formation, furnishes no fossils, except 
silicified wood, which is derived from the triassic beds of Deep 
and Dan rivers. These monotonous barrens are analogous to 
the prairie lands of the west. Towards the north the Atlantic 
slope becomes less sandy, and its vegetation is in accordance 
with a gradual change in climate and soil. To the south this 
plain extends westward and southward, and connects itself with 
the Mississippian, by turning around the southern points of the 
Appalachian chain in the north parts of Georgia and Alabama. 
§ 27. The Mississippi flows upon a low ridge or anticlinal 
axis. The country westward swells and rises gently, and 
finally attains, at the base of the Rocky mountains, an eleva¬ 
tion of about 5000 feet at the South pass. A pass lower by 
2000 feet has been discovered by Governor Stephens. The 
culminating points of the Rocky mountains are near Fremont’s 
peak and the three Tetons, as here the Colorado, the Missouri, 
and the Columbia take their origin. The Rocky mountains 
