I think that the company that you are looking for is as follows:

Army of Northern Virginia Army of Tennessee

Butler's Cavalry Brigade

4th South Carolina Cavalry Regiment
COL. B.H RUTLEDGE
LT. COLONELS: WM. STOKES and W.P. EMANUEL

The "Catawba Rangers" were Company H of the 4th S.C. Cavalry Regt. serving under Captains James D. and W.J. McIlwain