Doc. 201.-Gen. McClellan's staff.
Headquarters army of the Potomac, Washington, Aug. 20, 1861.In compliance with General Order No. 15, of August 17, 1861, from the Headquarters of the army, I hereby assume command of the Army of the Potomac, comprising the troops serving in the former departments of Washington and Northeastern Virginia, in the Valley of the Shenandoah, and in the States of Maryland and Delaware. The organization of the command into divisions and brigades will be announced hereafter. The following-named officers are attached to the staff of the Army of the Potomac: Major S. Williams, assistant adjutant-general; Captain Alex. V. Colburn, assistant adjutant-general; Col. R. B. Marcy, inspector-general; Col. T. M. Key, aide-de-camp; Capt. N. B. Swetzer, First Cavalry, aide-de-camp; Captain Edward McK. Hudson, Fourteenth infantry, aide-de-camp; Captain L. A. Williams, Tenth infantry, aide-de-camp; Major A. J. Myers, signal officer; Major Stewart Van Vleit, chief quartermaster; Captain H. F. Clarke, chief commissary; Surgeon C. S. Tripler, medical director; Major J. G. Barnard, chief engineer; Major J. M. Macomb, chief topographical engineer; Captain Charles P. Kingsbury, chief  of Ordnance; Brig.-Gen. George Stoneham, Volunteer service, chief of Cavalry; Brig.-Gen. W. S. Barry, Volunteer service, chief of Artillery.