Debbie,

There was a 2nd Tennessee Cavalry (Union) and a 2nd Tennessee Cavalry (Conf) and both had companies with the letter designation "A".

Confusing isn't it?

Your ancestor, Elijah K. Tomas, was in the 2nd Tennessee Cavalry (Union).

Did you see my earlier response to your posting at:

http://history-sites.com/mb/cw/tncwmb/index.cgi?read=1336

Jim Martin