"No source. The brigade was composed of four regiments composed largely of conscripts from East Tennessee. This is the brigade that broke at first contact at Big Black River."

Tony, I believe Vaughn's brigade was composed of three regiments as:
John C.Vaughn's Bgde
79th Tn [60th Tn]
80th Tn [61st Tn]
81st Tn [62nd Tn]

A W Reynolds commanded an East Tn brigade in Stevenson’s Division as:
Col. Alexander W. Reynolds
3d Tennessee Infantry (P. A.), Col. N. J. Lillard
31st Tennessee Infantry, Col. W. M. Bradford
43d Tennessee Infantry, Col. J. W. Gillespie
59th Tennessee Infantry, Col. W. L. Eakin

Coincidentally, General J. C. Vaughn was formerly Colonel of the 3rd Tn [P.A.] in Reynold’s Brigade