Of all the mountains upon the earth, so far as we are informed by our maps, none seem to be so regularly disposed as are the ridges of the Virginian mountains.  There is in that country a rectilinear continuity of mountains, and a parallelism among the ridges, no where else to be observed, at least not in such a great degree.

At neither end of those parallel ridges is there a direct conveyance for the waters to the sea.  At the south end, the Allegany ridge runs across the other parallel ridges, and shuts up the passage of the water in that direction.  On the north, again, the parallel ridges terminate in great irregularity.  The water therefore, that is collected from the parallel valley, is gathered into two great rivers, which break through those ridges, no doubt at the most convenient places, forming two great gapes in the blue ridge, 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