I was told by an ancestor of Thomas A. Hall, that he served in the 42nd Ms. Cavalry, but apparently they were wrong. I could not find him anywhere. I did notice that the 2nd Cavalry (also called 4th and 42nd Regiment) was organized during the spring of 1863. It was formerly the 4th Ms. Infantry Reg., which never completed its organization. I found this information on the 2nd. Reg. Ms. Cavalry. Thanks for your help.