Thomas launched a surprise amphibious landing at Brown's Ferry on October 27 that opened the Tennessee River by linking up his Army of the Cumberland with Hooker's relief column southwest of the city, thus allowing supplies and reinforcements to flow into Chattanooga over what was called the "Cracker Line". In response, Bragg ordered Lt. Gen. James Longstreet to force the Federals out of Lookout Valley. The ensuing Battle of Wauhatchie (October 28–29) was one of the war's few battles fought exclusively at night.