The website Civil War Soldiers and Sailors System http://www.itd.nps.gov/cwss/ contains the following information: HJG Smith, Private, Co C, Woods Regiment. here is a brief synopsis on that unit.

Wood's Regiment, Missouri Cavalry

14th Cavalry Battalion was organized during the spring of 1864 with six companies, later increased to eight. Serving unattached, then in General Shelby's Brigade, it was active in various conflicts in Arkansas and later took part in Price's Missouri Expedition. The unit was included in the surrender of the Trans-Mississippi Department but was probably disbanded in mid-May, 1865. Major Robert C. Wood was in command.

Maybe this will be of some help, good luck.