[Inclosure R.] GENERAL ORDERS,
HEADQUARTERS DISTRICT OF ARIZONA, Numbers 20.
Las Cruses, N. Mex., September 5, 1862.

I. Major Theodore A. Coult, Fifth California Volunteer Infantry, will proceed without delay to Tucson, and relieve Major David Fergusson, First California Volunteer Cavalry, in the command of the District of Western Arizona.

II. Major David Fergusson, First California Volunteer Cavalry is hereby relieved from duty as chief commissary of the Column from California, and will immediately transfer all funds, property, records, &c., pertaining to the subsistence department to Captain Nicholas S. Davis, First California Volunteer Infantry, who is hereby appointed acting chief commissary of the Column from California. Having done this, Major Fergusson will proceed, via Arivaca and Altar or Cubero, without delay, to a point at or near Lobos Bay, on the Gulf of California, known as Libertad, and examine the intermediate country, with a view to the transportation of supplies. He will ascertain the resources of the country on this route; also the availability of Lobos Bay as a port where the military supplies destined for Arizona may be landed. Major Fergusson will then repair in person to the headquarters District of Arizona, and make a report of his examination of the Port Lobos route to the general commanding the Column from California. As soon thereafter as practicable Major Fergusson will assume command of his regiment, the First California Volunteer Cavalry.

III. Captain Nicholas S. Davis, chief of transportation of the Column from California, will discharge all mechanics from Government employment at Tucson, except such as may be necessary to keep the train that plies to Fort Yuma in repairs. This train and any other quartermaster's property in Western Arizona for which he us responsible may, if the exigencies of the service so require it, be transferred by Captain Davis to the depot quartermaster as Tucson. Captain Davis and Lieutenant Lysander E. Hanson, First California Volunteer Infantry, with Mr. George C. Alexander, clerk to the chief commisary of the Column from Caliort by the first opportunity to the commander of the District of Arizona.

IV. Surg. John H. Prentiss, First California Volunteer Cavalry, will relieve Surgeon McNulty as medical purveyor of the District of Arizona, and will receipt for the medical supplies appertaining to the same.

V. Estimates for medical supplies and ammunition required at For Bowie and Tucson will be made upon the proper officers at the headquarters of the District of Arizona.

VI. Brigadier-General Carleton having been ordered to Santa Fe, to relieve Brigadier-General Canby, in the command of the Department of New Mexico, he hereby reinquishes the command of the District of Arizona to Colonel Joseph R. West, First California Volunteer Infantry. Brigadier-General Carleton still retains the command of the Column from California, and his staff - Actg. Asst. Adjt. General Benjamin C. Cutler, Surg. James M. McNulty, Lieutenant-Colonel Eyre, chief quartermaster, and Lieutenant Joseph F. Bennett, acting assistant adjutant-general - will accompany him to Santa Fe, starting to-day.

VII. The District of Arizona comprises the Territory of Arizona and that portion of New Mexico which lies south of an east and west line drawn through Fort Thorn and also Northwestern Texas. The executive powers assumed by Brigadier-General Carleton in his proclamation,