Is there a name associated with this battery? What kind of microfilm are you reading?
Here's Gen. Maury's report on the surrender of Fort Gaines:
Fort Gaines was garrisoned by six companies Twenty-first Alabama Regiment, two companies First Alabama Battalion, 40 Pelham Cadets, 120 reserves, and about 40 marines; in all, about 600 good troops. The fort was well supplied for six months. The three 10-inch guns were dismounted during the bombardment. Twenty guns remained in good order. The fort was uninjured, and could have long withstood attack.
There were no officers named Martin in the 1st Alabama Artillery Battalion. In fact, the only commissioned officer I can find in the garrison might have been Lieut. Ransom H. Martin, Co. "G", 21st Alabama Regiment.
The Official Records do not associate the name 'Martin' with a battery in this area. My best guess is there may have been a Marine Battery at Fort Gaines.