William A. Jackson, Private in Holmes' Company B, Clardy's Battalion, Missouri Volunteers, appears on a Muster and Descriptive Roll surrendered with the Army of the Northern Sub-District of Arkansas on May 11, 1865 by BGen. M. Jeff Thompson, paroled at Wittsburg, Arkansas May 25, age 40, Blue eyes, Dark hair, Fair complexion, 6' 1", resident of Wayne County, Missouri, born in Arkansas, another card lists him as swearing to the Oath of Allegiance to the US at Memphis on May 30, 1865
M322: Compiled Service Records of Confederate Soldiers Who Served in Organizations from the State of Missouri, Roll 64

Note: There are only 3 cards found in his CSR file, no information on his enlistment date other than he enrolled in Missouri

There is listed in the American Civil War Research Database, a Private William A. Jackson, Company K, Missouri Home Guard Infantry, However, I can find no records in the Compiled Service Records for this unit.