dge_, which is the most easterly of those parallel
ridges.

Now, so far as mountains are in the original constitution of a country,
the ridges of those mountains must have been a directing cause to the
rivers. But so far as rivers, in their course from the higher to the
lower country, move bodies with the force of their rolling waters, and
wear away the solid strata of the earth, we must consider rivers as also
forming mountains, at least as forming the valleys which are co-relative
in what is termed _mountain_. Nothing is more evident than the operation
of those two causes in this mountainous country of Virginia; the
original ridges of mountains, or indurated and elevated land, have
directed the courses of the rivers, and the running of those rivers have
modified the mountains from whence their origin is taken. I have
often admired, in the map, that wonderful regularity with which those
mountains are laid down, and I have much wished for a sight of that
gap, through which the rivers, gathered in the long valleys of those
mountains, break through the ridge and find a passage to the sea.
A description of this gap we have by Mr Jefferson, in his notes on
Virginia.

"The passage of the Potomac, through the Blue Ridge, is perhaps one of
the most stupendous scenes in nature. You stand on a very high point of
land. On your right comes up the Shenandoah, having ranged, along the
foot of the mountains, an hundred miles to seek a vent. On the left
approaches the Potomac, in quest of a passage also. In the moment
of their junction, they rush together against the mountain, rend it
asunder, and pass off to the sea.

"The first glance of this scene hurries our senses into the opinion,
that this earth had been erected in time; that the mountains were formed
first; that the rivers began to flow afterwards; that in this place
particularly they have been dammed up by the Blue Ridge of mountains,
and have formed an ocean which filled the whole valley; that, continuing
to rise, they have at length broken over this spot, and have torn the
mountain down from its summit to its base. The piles of rock on each
hand, but particularly on the Shenandoah, the evident marks of this
disrupture and avulsion from their beds, by the most powerful agents
of nature, corroborate the impression. But the distant finishing which
nature has given to the picture is of a different character. It is a
true contrast to the foreground. It is as placid and deligh