as sent forward from Piedmont to
Aldie, via Middleburg, to anticipate our troops in holding the Gap
there; it being considered important to occupy the Bull Run range
of mountains as a screen for Lee's further operations. Fitz Lee's
brigade was supported by that of Robertson which was moved to
Rectortown, where it was also available as a reserve to W. H. F.
Lee's brigade which had gone forward to occupy Thoroughfare Gap.
No opposition was anticipated in the latter place, Pleasonton having
moved to Centreville, with his main body. Stuart made his headquarters
at Middleburg on the 17th.

Fitz Lee halted near Dover to close up his command, and sent his
pickets on to Aldie Gap. Pleasonton, who was scouting in the
vicinity, had no orders to go through the pass, but felt prompted
to do so by one of those presentiments which rarely deceive. He
pushed on, therefore, with Gregg's division until about 2.30 P.M.,
when he came upon the rebel pickets, who fell back on the main
body. The latter had made a march of forty miles to reach the Gap,
and Fitz Lee chose a strong position on a hill directly west of
Aldie, in which to fight a defensive battle. His line covered the
road to Snicker's Gap, but could be turned by the road to Middleburg
and Ashby's Gap.

A sanguinary contest ensued, which, including the pursuit, lasted
until 9 P.M. The rebel front was strengthened by a ditch and a
line of hay-stacks. After fighting for three hours the battle was
finally decided by a gallant charge of the 1st Maine Cavalry, who,
after our line had been broken and driven back, were led by Kilpatrick
in person, against a regiment of mounted infantry on the Ashby's
Gap road, capturing four guns. The Harris Light Cavalry had been
in disfavor for having failed in an attack at Brandy Station, but
on the present occasion they redeemed themselves, made several
brilliant charges, and greatly contributed to the success of the
day.

The rebels claim to have taken 134 prisoners, and some flags in
this affair, and state that they only fell back to Middleburg in
obedience to Stuart's orders. Ascertaining that Colonel Duffie
was advancing on that place with his division, Stuart thought, by
concentrating his entire force there, he could overwhelm him. This
may account for the retreat, but it is very certain that the loss
of the pass at Aldie was a serious blow to the rebel cause. This,
supplemented by Colonel Duffie's operations, which will be descr