... us after the loss of Lookout or Wills's Valley, and no longer tenable against such an overwhelming force as General Grant had concentrated around Chattanooga.--Gen. Bragg abandoned also the whole of Chattanooga Valley , and the frenches and breastworks passing along the foot of Missionary Ridge and across the valley to the base of Lookout, and moved his troops up to the top of the ridge. It was found necessary to...