_ A. Guyot on the Appalachian Mountain System. 177 
above, or very near the surface of the ocean. The shallowness 
of the ocean for a considerable distance from the coast of New 
Jersey also indicates a prolongation of the continental plains 
under the sea, and the limit of the deep waters is there found 
at a distance nearly double that which is observed off the coast 
of the Carolinas. Moreover the parallelism which exists be- 
tween the line of coasts and all the great general inflections of 
the Appalachian system, a parallelism which is well marked 
from Nova Scotia to Florida, here undergoes a modification 
which is well explained only by a local depression of this part 
of the system. ‘The fact that all New Jersey is now undergoing 
gradual submergence from Cape May to the Bay of New York, 
which is proved by the numerous facts gathered by Prof. G. H. 
Cook in the Geological Survey of the State of New Jersey, is 
ere not without signification. : 
he disposition of the relief indicated above would be readi- 
ly accounted for by supposing that it is the result of a tilting 
motion from the north to the south, which, while depressing the 
northern portion below the mean altitude, elevated the south- 
ern region in the same proportion, the centre or axis of the tilt 
being in the vicinity of Christiansburg, near the Great Bend of 
the New River. As the movement affected more particularly 
the eastern, or mountainous belt, and not that of the plateaus of 
the west, the result of it was a twisting, the effect of which was to 
raise,,in the southern part, the mass of the land on the extreme 
eastern border and thus to produce an inclined plane towards the 
northwest; while in the northern part, the general depression of 
the land along the Atlantic, a depression not participated in 
the plateaus of the northwest, left to these latter all their alti- 
tude and produced an inclined plane from the extreme western 
border towards the southeast. It is then this particular disposi- 
tion of these two general slopes which gives us the key of the 
hydrographic system of the central and southern divisions of 
the Appalachian mountains, which at the first glance appears 
soabnormal. In the central section, as has been remarked above, 
north of New River, the water-shed is situated along the edge of 
the plateaus in the Alleghany mountain proper in Virginia and 
Pennsylvania, from which descend the James River and the Po- 
tomac; and still further to the west in the plateaus of New York 
from which flow the Susquehanna and the Delaware, traversin 
all the chains of the méuntainous region to the Atlantic. In the 
southern division, south of New River, the water-shed between 
the Atlantic and the Mississippi basin is situated upon the 
mit of the Blue River at the extreme eastern edge, and the nu- 
oe oe of the Tennessee which descend from sta 
raverse the whole mountainous region, but in an inverse direc- 
Yon, from the southeast to the northwest, and, united in the 
