As usual,or always, Alan is correct. Thomas Reid wrote a fascinating book about the 13th Texas (dismounted)Cavalry, not to be confused with the 13th TX Infantry.
This cavalry unit was dismounted in Arkansas after high command" figured out that there was no logistical support to provide forage for the horses and the CSA needed infantry far more than cavalry. Hell, there was not enough forage for the soldiers in Arkansas!
It was not Waul's Brigade, but Walker's Greyhound Division that brought these heroes to prominence at Mansfield, Pleasant Hill and Jenkins Ferry.
God bless the 13th TX Cavalry and be forever Texas Proud.