elevations. The Blue Ridge borders the county on the west, its course
being about south southwest, or nearly parallel with the Atlantic
Coast-line, and divides Loudoun from Clarke County, Virginia, and
Jefferson County, West Virginia, the line running along the summit.

Of nearly equal height and similar features are the Short Hills,
another range commencing at the Potomac River about four miles below
Harpers Ferry and extending parallel to the Blue Ridge, at a distance
of nearly four miles from summit to summit, for about twelve miles
into the County, where it is broken by a branch of Catoctin Creek.
Beyond this stream it immediately rises again and extends about three
miles further, at which point it abruptly terminates.

A third range, called "Catoctin Mountain," has its inception in
Pennsylvania, traverses Maryland, is interrupted by the Potomac,
reappears in Virginia at the river margin, opposite Point of Rocks,
and extends through Loudoun County for a distance of twenty or more
miles, when it is again interrupted.

Elevations on Catoctin Mountain progressively diminish southward from
the Potomac River to Aldie, although the rocks remain the same, and
the Tertiary drainage, which might be supposed to determine their
elevations, becomes less effective in that direction.

Probably this mountain does not exceed an average of more than 300
feet above the surrounding country, though at some stages it may
attain an altitude of 700 feet. Rising near the Potomac into one of
its highest peaks, in the same range it becomes alternately depressed
and elevated, until reaching the point of its divergence in the
neighborhood of Waterford. There it assumes the appearance of an