This appears to be Pvt William H. Zumwalt, who enlisted in Co F, 8th MO Inf Regt, at Thomasville, MO, on Aug 7, 1862. He was 25 years of age, 5' 8" tall, blue eyes, light hair. He was left sick at Yellville, Ark on Nov 6, 1862. Thereafter went absent without leave. Captured at date and place not definitely known, although he is likely the person captured in Pulaski County, MO, on Feb 23, 1863. He was eventually exchanged at City Point, VA. Appears as sick at Richmond at the small pox hospital Jul 11, 1863. Returned to duty. Enlisted in Woodson's Co. in July, 1863.

Although Woodson's Company is usually listed as Company A, 1st MO Cav Regt, it in fact had no association with that regiment at all. Woodson's men were all exchanged Missouri prisoners of war that emanated from a good many MO regts.

I hope this helps.