route. The Parisian colonel finally returned to Centreville with only 4 officers and 27 men. A few stragglers eventually rejoined the shattered remnants of the regiment. Duffié would never again serve with the Army of the Potomac, although he did command cavalry in other Union armies. The Union casualties on July 17 were reported as 250. Fight on June 19 After the Battle of Aldie, Stuart remained on the defensive, wanting to spoil any Federal attempts to force the passes in the Blue Ridge Mountains. Pleasonton tentatively sent probes towards Ashby's and Snicker's Gaps. On June 18, David McM. Gregg ran into Confederate pickets around Middleburg, and Stuart quickly fell back to a commanding ridge west of town. Fearing a trap, a cautious Pleasonton ordered Gregg to withdraw to Aldie. The next day, Gregg again moved against Middleburg, sending the brigade of his first cousin, Col. J. Irvin Gregg, at the Rebels while John Buford's division swung north towards Pot House (New Lisbon). After a flanking march, Buford eventually occupied the ground around Pot House, pushing back two regiments of William "Grumble" Jones's brigade in a mild skirmish. After a hard fight to clear reinforced pickets from Middleburg, Colonel Gregg was so impressed by the Confederate position on the high ground beyond the town that he asked for support before attacking. Kilpatrick sent two regiments to help extend the Federal line, and Gregg slowly advanced. The temperature hovered around 98 °F throughout the afternoon, sapping men and horses of energy. A series of Union charges finally forced Stuart's horse artillery to withdraw, and then his cavalry. Several Confederate counterattacks failed to regain control of the ridge. Late in the day, Buford sent the U.S. Reserve Brigade back from Pot House, and the 2nd and 6th U.S. Cavalry regiments seized a hotly contested hill south of the tiny village of Millville as darkness fell. Stuart was forced to abandon his position, falling back along the turnpike to stonewalls beyond a ravine along a stream known as Kirk's Branch. A still cautious Pleasonton refused to follow up his success and ordered his men to rest and send out pickets. Union losses in the June 19 fight were reported as 16 killed, 46 wounded, and 37 missing. Stuart lost perhaps 40 men, including his chief of staff and friend, Prussian cavalier Heros von Borcke, who was badly wounded by a bullet in his