There were actually two separate units that used the designation 13th TX Cavalry. One was a cavalry unit; the one in which you were looking. The other was referenced as the 13th TX Volunteers. They consisted of cavalry, artillery, and infantry. You'll find your ancestor there. However, this unit was reorganized numerous times, and your ancestor was a part of those modifications. He was transferred to the 12th TX Cavalry Battalion that later became the nucleus of the 35th TX Cavalry. You'll find him listed with each unit.

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