I have been unable to find any listings of the following companies in the Order of Battle of the Army of the Potomac which, to my knowledge, they were assigned. If anyone has any information on these companies please leave your comments.
Prince William Cavalry – Independent Virginian cavalry company believed to be assigned to the extreme right guarding Davis' ford. No records or documentation of brigade assignment has been found. The company was assigned as Company A, 4th Virginia Cavalry, during September 1861.
Madison Cavalry – Independent Virginian cavalry company with no record or documentation of brigade assignment found. The company was assigned as Company C, 4th Virginia Cavalry, during September 1861.
Schaeffer's Virginia Battalion Infantry – The battalion was temporarily organized on July 21, 1861 and attached to the Fifth Brigade, Army of the Potomac. Companies attached are believed to be the Beauregard Rifles, the Crescent Blues Company B and the 1st Company Foot Rifles. There is very little record or documentation of these companies.