I'm not sure if this could be the unit but it's the only thing I could find. I found it here: http://www.angelfire.com/ga2/PhillipsLegion/jjohnson.html

"When war broke out in 1861 Governor Brown went to work to build a State Army for Georgia and the 4th State Brigade was organized at Camp McDonald in May 1861. One of the two heavy infantry regiments included in this brigade was commanded by State Colonel William T Wofford. In Company #1 of the regiment (The McDonald Guards), J M Johnson is listed as it's Captain on a roll dated May 12th 1861. Governor Brown addressed the brigade in June and when he indicated that he planned to retain the brigade in Georgia to defend the state, a number of companies, anxious to fight Yankees, disbanded and left the brigade to enlist in other units that were headed for Virginia. James was apparently one of these men since he next turns up as a Sgt in Co E of the 14th Georgia Infantry."