The last of Lee's forces to cross the Potomac was his rearguard. This was a force of about 3,000 men commanded by Major General Henry Heth. They took their positions on the ridge behind Falling Waters after marching all night. On the morning of July 14, Meade was surprised to learn Lee had withdrawn most of his army across the Potomac. He immediately ordered two companies of Michigan cavalry under the command of a newly promoted General George Armstrong Custer to attack. The cavalry charged up the ridge to attack Heth's Confederates but were cut to pieces. Custer dismounted his cavalry and proceeded to fight on foot. At first the Confederate casualties were light. But in heavy fighting Confederate General J. Johnston Pettigrew, who commanded a North Carolina brigade under Heth, was mortally wounded. Additional Union forces arrived and in over two hours of fighting, over 500 Confederates were captured. Heth's men, carrying the wounded Pettigrew, withdrew over the river ending the battle. The Battle of Falling Waters was the last battle in the Gettysburg Campaign.