Lucretia,

According to the official records , the only Texas units at Gettysburg were the 1st,4th and 5th Texas Infantry Regiments which were part of Brig Gen J.B.Robertson's Brigade , Hood's Division , Longstreet's Corps. Once again, according to the official order of battle records,there were no Texas Cavalry Units nor Texas Artillery Units at Gettysburg. Those three regiments certainly had a famous reputation that started back at Gaines' Mill when they broke through the Union lines , giving Lee his first victory as Commander of the Army of Northern Virginia.
Regards, Craig