As advancing Federal troops climbed out of the hollow to the front, Confederate defenders crowded a fence line in concealment, some having stuffed leaves between the bottom rails and lying flat with their guns in the crack of the fence while the unaware Germans advanced in a beautiful two-rank line. A few members of the 15th Alabama fired too soon, but the Federals kept coming until they were at point-blank range before the 21st Georgia, when Colonel John Mercer gave the order to fire and a devastating volley erupted. Many of the defenders used smoothbore muzzle-loading muskets loaded with buck and ball, and some used cartridges with even more buckshot, making the fire especially destructive at close range. The Germans fell in heaps, the firing lasted only a few rounds through the smoke, and within little more than a minute the survivors were fleeing toward the far woods as the Union attack collapsed in disaster, though General Isaac Trimble was not yet finished.