GEOLOGY AND THE BATTLE OF PERRYVILLE

During the American Civil War, Confederate forces invaded the border state of Kentucky, and the campaign culminated in the Battle of Perryville on October 8, 1862. Although poor intelligence, leadership mistakes, and sheer luck contributed to the outcome of the campaign, geological factors played key roles in the campaign for Kentucky.

One of the most significant factors in the campaign was a desperate shortage of water for the troops. The area was suffering a severe drought at the time. Only major streams and selected epikarst-fed minor streams, such as those at Perryville, could supply adequate water for a large army. The precious pools of water along the Chaplin River and Doctors Fork attracted the troops of both armies.

Terrain, strongly controlled by the underlying bedrock, also played a key role in the campaign and subsequent battle. A steep escarpment, known formally as the Knobs, surrounds Kentucky's Bluegrass Region and served as a barrier to efficient transportation. As the Federal army advanced from Louisville searching for the Confederate forces, they kept one flank anchored on or near the Knobs during their advance. They thus used the forbidding terrain to protect that flank and help deter Confederate threats to Union supply lines.

The terrain of the battlefield itself also played a role in the savagery of the fighting. The rolling topography limited visibility, enabling attacking units to get within close range before coming into view, making small arms and cannon fire particularly effective. Some units lost up to half of their men as casualties. Walkers Bend, a prominent meander of the Chaplin River, was a notable place of concealment for Confederate forces before they attacked. Stone fences constructed of bedrock quarried from local creek beds provided defensive shelter for defending troops and obstacles for attacking units to surmount.

Another facet of the Perryville battle was an "acoustic shadow"--Union headquarters did not hear the sounds of the battle until late in the afternoon. Wind direction and distance from the fighting played a role in the "shadow," but the shape of the fluvially carved landscape sheltered the headquarters area from the sounds of the battle, while people as far away as Louisville (>50 airline miles) heard the cannonade.