Another of my 2nd great-grandfathers, Hiram George Shoemaker, died in July of 1864, near Atlanta, while serving in the 28th AL Infantry. "Those Gallant Men of the Twenty-Eighth Alabama Confederate Infantry Regiment" by James H. Walker and Robert Curren is a great book with lots of information about the men in that regiment. Your Mark is referred to in the book.
The book "Theophilus" --A story depicting the lives and history of: THE SOD-BUSTIN', TOBACCO-CROPPIN', COTTON-PICKIN' SOUTHERN GOODWINS by Ron Goodwin is "(A somewhat fictitious autobiography of Theophilus Goodwin and his descendants)" About half the book is devoted to the genealogical lines of Theophilus Goodwin.
I would like to recommend Alan Pitts, he was able to find quite a few military service records on my Jefferson County AL ancestors who fought for the Confederacy. The pension applications were very informative and give insight into their lives. I think Alan found service records on 7 for me in the Jefferson County AL area.