RADFORD – Radford University geology professor emeritus Bob Whisonant has examined the 25 bloodiest battles of the Civil War and found that the number of casualties suffered at some of those battles may have been determined as much by the ground beneath the soldiers’ boots as the bullets flying in the air.

Whisonant and former U.S. Army terrain specialist Judy Ehlen, now a geology research associate at RU, studied the geomorphology of several battlefields and compared the terrain to known casualties for each fighting day. The two researchers discovered that soldiers were indeed at greater risk at some battle locations because of the geological formations underneath the battlefields.

Whisonant notes that Gettysburg is a prime example of where the Union had the advantage of the high ground, but also had some disadvantages caused by the geology. The Union soldiers were positioned on the hard rock that forms the high ground, and the rock was so close to the surface that the soldiers couldn’t dig trenches.

“The Union soldiers were open targets for artillery assault by the Confederates,” Whisonant said. “But the disadvantage didn’t just go one way. The Confederate soldiers had to go up an open slope formed on more erodible rock with nothing to get behind when they finally had to attack."

Whisonant and Ehlen also studied the terrain at Antietam, the site of the bloodiest battle in the Civil War, where on September 17, 1862, up to 23,100 soldiers were killed, wounded, or declared missing.

"What’s so striking at Antietam is that two geologic units underlie that area,” Whisonant said. “One is a very, very pure limestone that, as it erodes, it literally melts. Mostly what you get with that is a very even, level, open surface -- there just aren’t a lot of deep holes and high hills that give soldiers a place to hide." On one area of this flat surface, known as Miller's Cornfield, "armies just shot each other to pieces until absolute exhaustion set in."

Whisonant and Ehlen presented their research in October at a meeting for The Geological Society of America.