Confederate guns through having longer range and better ammunition. The Union 1st United States Sharpshooters took up positions along the Chesapeake and Ohio Canal and harassed the Confederate gunners with fire, but Armistead and Lawton's men at the ford had been ordered to only fire if the Union made a major attempt at crossing. The order was given to preserve ammunition. Pendleton dispatched 200 of the infantrymen to support some of the batteries, and a further sixty were sent to support the Confederate cavalry at the southern ford, likely without Pendleton's knowledge. The infantry defenses at the ford were soon stripped to just 300 men. Pendleton did not coordinate between his artillery and infantry units, and later claimed a lack of knowledge of how many men he had available. At dusk, a 60-man raiding party from the 1st United States Sharpshooters crossed the ford under covering fire from the 4th Michigan Infantry Regiment. The raiding party lost four men during the crossing. Lawton and Armistead's men, who were in poor condition and had low morale after suffering heavy losses at Antietam, quickly fled. Pendleton's staff was not present, and in the dark and with essentially no knowledge of what was happening at the ford, Pendleton left the field. Part of Colonel James Barnes's brigade moved across the river as well. While a Union force of about 2,000 men in total only advanced a short distance from the ford before withdrawing with four captured guns and some prisoners, Pendleton's line routed. The Union forces had been delayed by the high cliffs until the Confederate artillery had almost entirely withdrawn. During the retreat, Pendleton met the infantry force of the incompetent Roger A. Pryor, and asked Pryor to advance and rescue his cannons, but Pryor would not. Pendleton eventually found Lee and inaccurately told him that all of his cannons had been taken. Lee spent the night vainly trying to ascertain knowledge about the situation while Pendleton slept. Lee decided to postpone any counterattack until morning. Lawton's command had lost seven men wounded, while Armistead's losses were unknown but light. September 20 On the morning of September 20, Porter sent three brigades across the river. Charles S. Lovell's brigade led the way, followed by Barnes's and Gouverneur K. Warren's. Confederate general Stonewall Jackson decided to attack and drive the Union forces back into Maryland. Selecting A. P. Hill's Light Division, Jackson ordered