Confederate earthworks such as General Joseph E. Johnston had caused to be thrown up by the Negro laborers all along his line of possible retreat. McPherson, sent by Sherman to strike the railroad in Johnston's rear, got his head of column through Snake Creek Gap on May 9th, and drove off a Confederate cavalry Brigade which retreated toward Dalton, bringing to Johnston the first news that a heavy force of Federals was already in his rear. McPherson, within a mile and a half of Resaca, could have walked into the town with his twenty-three thousand men, but concluded that the Confederate entrenchments were too strongly held to assault. When Sherman arrived he found that Johnston, having the shorter route, was there ahead of him with his entire army strongly posted. On May 15th, “without attempting to assault the fortified works,” says Sherman, “we pressed at all points, and the sound of cannon and musketry rose all day to the dignity of a battle.” Its havoc is seen in the shattered trees and torn ground in the lower picture.