 Its supporting forces on the right and left both gone, the 151st Pennsylvania was soon entirely alone on McPherson's Ridge.The regiment had sustained heavy casualties from its front and its exposed left from Pettigrew's North Carolina troops.Seeing the regiment's vulnerable position, Lt. Col. McFarland ordered his remaining men to conduct a steady retreat back across the hollow to the Seminary, where other I Corps regiments were rallying and digging in for the next wave of Confederate attacks.