Grant's armies converged on Chattanooga and planned to attack Bragg's army. Getting into place required the XI and XII Corps to cross the Tennessee River at Bridgeport, Alabama, and march rapidly for Lookout Valley, opening the supply line to Chattanooga. They did so, to the surprise of the Confederate forces there, which had not expected an attack from that quarter. On October 28, Hooker's two corps were attacked by a part of Bragg's army, which had by now been joined by Longstreet and some units from the Army of Northern Virginia. Bragg ordered Longstreet to drive the federals back and he attacked. In the ensuing Battle of Wauhatchie, the XII Corps took the brunt of the initial assault. Hooker bypassed Howard and ordered Schurz to bring up the XI Corps to join the fight. The engagement was confused on both sides, but the Union forces were victorious, driving off the rebels and inflicting twice the casualties they received. With the supply lines now reopened to Chattanooga, Grant planned to dislodge Bragg's army. At the Battle of Lookout Mountain, the 68th was held in reserve on the first day, November 24. The battle continued the next day and a part of Howard's XI Corps, including the 68th, was shifted to the far left of the Union lines to reinforce Sherman's attack on Missionary Ridge. There, the 68th skirmished with the enemy, but was unable to advance. The Confederates were forced to retreat, however, as Maj. Gen. George Thomas's troops' assault on their center sent Bragg's army into retreat from the ridge.