Friday, July 3, 1863
The Twentieth Massachusetts suffered heavy casualties at Gettysburg, particularly during the hand-to-hand combat to seal the Union line at the Angle near the copse of trees. Private Oliver Stanton Bates was most likely wounded during this hand-to-hand fighting. His service records state that he received a head wound, but no other details concerning his wounding were listed. Apparently his wounding was severe, as he did not report again for military duty until January 1864. This six-month interlude after Gettysburg was the only time during his entire military service that he did not report for duty.1
1Compiled service record, Oliver S. Bates, Pvt., Co. A, 20th Massachusetts Infantry; Carded Records, Volunteer Organizations, Civil War; Records of the Adjutant General's Office, 1780s-1917, Record Group 94; National Archives, Washington, D.C.