In the book called VIRGINIA MILITIA IN REVOLUTIONARY WAR by J. T. McAllister:
"1779 under Col. John Bannister to form a guard of 13 men to guard munitions of war at Petersburg."
"Capt. Robert Bolling - early in 1780 raised troop south of the James River, Col. Bannister, of Dinwiddie, commanding the militia. Marched troops into actual service under Col. Parker, of General Mullenberg's Brigade. Held position for some time of Norfolk and Portsmouth. Early next Spring resumed duty.
If all else fails I use Google. I find so much there it amazes me.