Late in the afternoon, during an attempt to make a coordinated attack on the Rebel line, several Federal units under the command of Col. William S. Smith were ordered deep into the ravine known as Pierson Hollow. The plan was called off because of the fading daylight. Confused, tired, and traveling in darkness in the thick woods, members of the 13th and 23rd Ohio mistakenly fired upon the 28th Ohio, killing two soldiers and wounding some 30 men.