I can't add much to what Alan has posted. Would like to say that the following is what I have on your ancestor, and would like more information if you have it [or corrections].

SUMMERVILLE [SOMERVILLE], W.H., 2nd Sgt., promoted to 1st Lt. commanding company at surrender. [Buried at Oak Grove Cemetery in Pickens Co.]

Note that there was also a Private William D. Somerville serving in the 7th Alabama Cavalry, Co. I [which was also primarily raised in Pickens County]. Cousins?

We have discussed this company quite a bit on this board. Use both search features to find the discussions.