James K. Hogue, "Wood, Thomas John," American National Biography Online, February 2000, http://www.anb.org/articles/05/05-00853.html.
In 1863 Wood's role in the battle of Chickamauga provoked fierce controversy in the Union high command. In October 1862 Abraham Lincoln had relieved Buell and replaced him with Major General William S. Rosecrans. On the second day of the battle, 20 September 1863, Rosecrans personally and vehemently ordered Wood to move his division, which Wood promptly did, even though it left more than a quarter-mile gap in the Union line. Confederate general James Longstreet's corps, on loan from the Army of Northern Virginia, attacked into this gap, cutting Rosecrans's army in two and threatening to destroy the entire army. Rosecrans was furious with Wood and blamed him for the blunder. General Ulysses S. Grant, however, saw the incident in a different light and chose, with the advice of Major General George H. Thomas, to keep Wood but relieve Rosecrans.