Thanks, Lt. Mayne was assigned to duty at HQ in St. Louis MO while carried on the roster of the 3rd Iowa Cavalry (His father Capt. Emanuel Mayne commanded Co. G and was KIA at Kirksville MO 6 Aug 1862) after which he stayed on working under Col (Genl) Bonneville, commander of Benton Barracks. It was Bonneville who appointed Lt. Mayne to the roster of the Marine Brigade as Adj early in Feb. 1863 and it was the Lincoln signed confirm of his promotion to 1st Lt. which Lt. McCune was carrying with him when they met as planned at Island 26. I have confirmation that McCune went overboard with over 200 enlistment/promotion orders as they were meeting (confirmed in a letter sent by the McCune family attorney in support of a pension claim after the war). Lot of the dates you noted were entered incorrectly into the system and I have found the morning reports of the units, as well as St. Louis archives to be more accurate. The actual roster of the MMB lists as of March 5, 1863 that 2nd Lt. Mayne was third in command of a Cavalry Company assigned to the BALTIC(Capt Oscar Brown, 1st Lt. Samuel Carlisle, 2nd Lt. Mayne) as well as on the roster as 1st Lt. Lee Roy Mayne, Adj of the Cavalry Btn. I also have their orig enlistment records which have varied other dates misfiled in Missouri Inf and Cav records with even McCunes records incorrectly listed as McClure W. Thompson of Missouri Infantry although correctly was a Federal Vol unit directly under Secy of War Stanton and Pres. Lincoln. Thanks for the response