Samuel's grave stone states he was a private in the 27th Brig Texas Militia CSA

I have the following information from a muster roll - I believe he died during the war. I also have a number of other Allison relatives that probably joined the same unit - Green, James, Simeon - any info would be appreciated.

Name and Rank: Allison, E. C., Pvt.
Comm. Off. Berry, A. J., Capt.
Organ: Co. A, 2nd Regt., 27th Brig. H.P. Hale, Brig. Gen., TST (Vol. CSA)
Enlist: Aug 7-63 at willow Springs, Bell Co. for 6 months unless sooner dischgd.
Descrip: Age 33
Remarks: R&F 75, H.P. Hale, Mus. Off., Constant Hardeman & Jasper McKinney,
Appraiser; 20 ms to rendez; Value of: horse $200; horse equip. $25; arms $50. Election certificate with roll and Samuel A. Easly was elected Major of Battalion; called into service of Confederate States by Gov. Lubbock.

I found a cemetery marker for J Shirley in Lowndes Co, MS. The marker only has his name (as listed) stating he served in the 27 Tex Inf Co A. Trying to find more info for J Shirley.