It should have read "First Brigade, Army of Western Virginia" which is a confederate force.
This date range would place the actions most likely in about August 1863 in the actions around White Sulpher Springs.... whereas this force opposed Federals as part of one of the segments of Averills Raid's. Colonel Corn of the 8th Va Cav was not captured. Lieut E.C. Gordon was the brigade ordnance officer, and possibly serving/assisting the quartermaster as well.

In this action assorted goods such as weapons and saddles were captured from or abandoned by the enemy, and usual habit to turn in anything of value not immediately needed to QM or Ord that can be repaired/reused/reissued.

Frederick