Here are a number of possibles. You can visit the NPS Soldiers and Sailors System at: http://www.itd.nps.gov/cwss/, where you can obtain thumbnail sketches of each of these units histories, which might narrow your search.

George Martin

George W. Walker, age 26, born in England, enlisted in Company D, Griffin's Regiment Texas Infantry November 29, 1862 at Houston, discharged and transferred to C. S. Navy steamer C.S. Harriett, Lane February 16, 1863, recorded as a Seaman, age 27, on board C. S. Diana October 23, 1863,

Griffin's Battalion (also known as the 21st Regiment, of Battalion,and as Griffin's Regiment) Texas Infantry .

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George W. Walker, enlisted as a Private in Company E, 25th Texas Cavalry March 15, 1862 at Millican, served as Forage Master, captured at Arkansas Post January 11, 1863, arrived Camp Butler, Illinois January 31, 1863, died of disease, Variola (Smallpox) April 30. 1863 at Petersburg

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George W. Walker, enlisted October 2, 1861 at Camp Reeves, Texas in Company E, 11th Texas Cavalry, served on extra duty as a Teamster, under arrest at Ashville, North Carolina February 29, 1864, no further records

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There also the following G. W. Walkers who served in Texas units:

"A" Co. TX 2nd State Troops Cavalry

"I" Co. TX 4th Cavalry

"H" Co. TX 6th Cavalry

"I" Co. TX 26th Cavalry

"C" Co. TX 2nd Infantry

"B" Co. TX 4th Infantry

"H" Co. TX Waul's Legion Cavalry

"A" Co. TX 13th Infantry

"Currie's" Co. TX Currie's Infantry

And then these George Walkers:

"H" Co. TX 7th Cavalry

"B" Co. TX 1st Infantry

TX 11th Light Artillery