Correspondence from the O.R.'s, Series 1 - Volume 49 (Part II), page 226:

[...] A refugee from Mobile, March 22 [1865], who was clerk at General Maury’s headquarters, states that French’s division is commanded by General Cockrell, and is composed of Cockrell’s old brigade, Sears’ and Gibson’s brigades, number not known. Thomas’ brigade consists of the First and Second Alabama State Reserves (old men). The regiments are quite full. McCulloch’s brigade rejoined Forrest’s command some time since. Colonel Fuller commands a brigade of heavy artillery, the First Louisiana Heavy Artillery, the Twenty-second Louisiana Infantry, Colonel Patton; the Twenty-first Alabama, Lieutenant Colonel Williams, and the batteries from Hood’s army, including Tobin’s, Garrity’s, and Cul-
peper’s. General Liddell commands a division of his own, Baker’s and Holtzclaw’s brigades. Holtzclaw’s brigade consists of the Thirty-second, Thirty-sixth, Thirty-eighth, and Eighteenth Alabama Infantry. The Twenty-first Alabama occupy part of the water defenses and the Twenty- second Louisiana the rest.

I have the honor to be, very respectfully, your obedient servant,
A.M. JACKSON, Major, Tenth U. S. Colored Heavy Artillery.
(In absence of Capt. S. M. Eaton, chief signal officer, Military Division of West Mississippi.)

[Enclosure.] French’s old division, commanded by General Cockrell, composed of Cockrell’s old brigade, Sears’ and Gibson’s brigades. Gibson’s brigade, 2,000; Sears’ brigade (this may possibly be Cockrell’s), unknown; Cockrell’s brigade (smaller), unknown. General D. H. Maury (old command), comprising militia, State reserves, British guards, Pelham Cadets, French guards, consular guards, regiment of employes, and garrison of fortifications, in all 6,000. Of this force General Liddell commands a division of his own, Holtzclaw’s and Baker’s brigades. Holtzclaw’s brigade has the Thirty-second, Thirty-sixth, Thirty-eighth, and Eighteenth Alabama Infantry. Fuller’s brigade consists of the First Louisiana Heavy Artillery, the Twenty second Louisiana Infantry, Colonel Patton; the Twenty-first Alabama Infantry, Lieutenant-Colonel Williams, and detached batteries from Hood’s army serving as heavy artillery. Garrity’s State artillery, two guns, sixty men; Todd’s battery, fifty-five men; Charpentier’s battery, six guns; Tobin’s battery; Culpeper’s battery. Thomas’ brigade, of the First and Second State Reserves, full regiments. Clanton’s brigade, the Sixth and Eighth Alabama Cavalry, Fifteenth Confederate Cavalry.

Note: I have seen somewhere in the O.R.'s, but can't find it right now, that Thomas' Brigade was moved out of the Spanish Fort/Mobile area before attacks began.

I would also draw attention to Series 4 - Volume 3, Beginning with page 1059 for indepth discussion of enlistment of 17 year olds and those younger. This is pertinent to this discussion and previous discussions that we've had here about the reserves. This can be read online at http://library5.library.cornell.edu/moa/moa_browse.html