But the Union army was repulsed at Lynchburg. The late afternoon of June 17, Hunter's forces began retreating. At about 3:00 A.M., they reached the Big Otter River. Hunter had ordered the pontoon bridge destroyed so that Confederate forces could not attack him from the rear. But now, needing another bridge built, Meigs could not be found. With the entire Army of the Shenandoah imperiled by Meigs' absence, Hunter fired him as engineer and appointed Captain Frank Martindale of the First New York Cavalry as engineer in his place. His supply lines long and under attack and supporting armies stymied in their attempt to reach him, Hunter retreated back to West Virginia. In his after-action reports, Hunter had nothing but scorn for Meigs. Meigs learned of his replacement only when Powell's cavalry rejoined the Army of the Shenandoah about June 20.