...river and prepared to hold its passes. On the 24th of August, General McDowell's corps was at or near Warrenton. On the morning of the 27th of August, he was directed to move forward rapidly on Gainesville , by the Warrenton Turnpike. And the required position was reached before the next day. On the next evening a brisk engagement took place at Thoroughfare Gap between the advance of the Rebel force u...