CHATTANOOGA: SIGNIFICANCE OF GEOLOGY DURING THE AMERICAN CIVIL WAR

Geology significantly influenced the importance of Chattanooga, Tennessee and the military campaigns waged for it during the Civil War. It lies on a bend of the Tennessee River, at the boundary between the Cumberland Plateau and the Valley and Ridge Province of the Appalachian Mountains. Chattanooga was an extremely important military objective due to its manufacturing capacity and railroads. Furnaces supplied with nearby deposits of Silurian iron ore and Upper Carboniferous coal contributed to its industrial base. Because of its geographic position, it was the major rail hub of the South, with connections to all points within the Confederacy and theaters of war.

The Union attempt to occupy Chattanooga began in December of 1862, when it was stopped at the Battle of Stones River. The next attempt to wrest control of the city from the Confederates came in the summer of 1863. After a successful flanking maneuver by Federal forces, the Confederate Army of Tennessee evacuated the city. Subsequently, the Union Army of the Cumberland was defeated at the Battle of Chickamauga in September, forcing a retreat to Chattanooga. As the Federal forces were besieged in Chattanooga, a plan was put into effect to break the siege. The bend of the Tennessee River around Moccasin Point was the key element of this plan. The supply line was over sixty miles long and subject to attack. Crossing the neck of the meander and capturing Brown’s Ferry opened a new eight-mile supply line. This lifted the siege and set the stage for the Union breakout of Chattanooga.

Lookout Mountain, capped by Upper Carboniferous coarse clastics, and Missionary Ridge, capped by Ordovician chert, surround Chattanooga. Confederate forces occupied this high ground. In late November of 1863 the Union army attacked Confederate positions on Lookout Mountain and Missionary Ridge. A natural bench on the slope of Lookout Mountain was the route taken by Federal forces to isolate the Confederate position on the top, forcing its withdrawal to Missionary Ridge. The Union army also took Missionary Ridge. These actions set the stage for Sherman’s Atlanta Campaign, begun in May of 1864.