Banks advanced again on April 16, surprising Ashby's cavalry by fording Stony Creek at a place they had neglected to picket, capturing 60 of the horsemen, while the remainder of Ashby's command fought their way back to Jackson's position on Rude's Hill. Jackson assumed that Banks had been reinforced, so he abandoned his position and marched quickly up the Valley to Harrisonburg on April 18. On April 19, his men marched 20 miles east out of the Shenandoah valley to Swift Run Gap. Banks occupied New Market and crossed Massanutten Mountain to seize the bridges across the South Fork in the Luray Valley, once again besting Ashby's cavalry, who failed to destroy the bridges in time. Banks now controlled the valley as far south as Harrisonburg.