Grant’s plan of battle was for Sherman with his four divisions to cross the Tennessee River at Brown’s Ferry and march behind Stringer’s Ridge, concealed from the eyes of the Confederates, and take a position near the North Chickamauga Creek. He was to recross the river by pontoon bridge at the mouth of the South Chickamauga Creek, strike the north end of Missionary Ridge and capture it as far as the railroad tunnel. Thomas was to move his Army of the Cumberland to the left, and connect with Sherman. This united force was to sweep the Confederates southward off Missionary Ridge and away from their base of supplies at Chickamauga Station. Howard’s Corps was to act as a general reserve for this force. Hooker, with the Twelfth Corps and Brig. Gen. Charles Cruft’s Division (Fourth Corps), was to hold Lookout Valley. Col. Eli Long’s Cavalry was to cover Sherman’s left and when no longer needed for this task was to strike Bragg’s communications. This original plan, however, was changed several times to fit the situation. The rains that hampered movement of Union supplies also delayed Sherman’s movement across the Tennessee. High water broke the bridge at Brown’s Ferry and Osterhaus’ Division could not cross the river. Subsequently it received orders to join Hooker in Lookout Valley. On November 22, Grant received word that Bragg was withdrawing his army; actually the movement reported was Buckner leaving to reinforce Longstreet. To “test the truth” of the report, Grant changed his plans and ordered Thomas to make a demonstration to his front on the 23rd. This began the battles of Chattanooga. ORCHARD KNOB. The Union Army of the Cumberland had made its positions very strong during the time it was besieged by Bragg’s army. One of its strong points was Fort Wood on an elevated point east of the town. Thomas, according to instructions, sent Maj. Gen. Philip H. Sheridan’s and Brig. Gen. T. J. Wood’s divisions to level ground at Fort Wood and there formed them in line—Wood on the left, Sheridan on the right, with Brig. Gen. Absalom Baird supporting Sheridan. Brig. Gen. R. W. Johnson’s troops held the trenches, and Maj. Gen. O. O. Howard’s Corps, which had crossed from the north bank of the river, acted as the reserve. Table 3.—_Union Army at Chattanooga_ Maj. Gen. Ulysses S. Grant