George Wright to Lorenzo Thomas, March 18, 1862

Brig. Gen. L. THOMAS, Adjutant-General U. S. Army, Washington, D. C.:

GENERAL: On the 14th instant I had the honor to acknowledge (by telegraph) the receipt of your dispatch of the 12th* relieving MajorGeneral McClellan from the command of the military departments, excepting that of the Potomac, and directing that hereafter reports be made direct to the Secretary of War. A company of marines having been landed at the navy-yard, Mare Island, from the U. S. flag-ship Lancaster, the presence there of the thirty soldiers of the Third Artillery, as a guard, was no longer required. The detachment has accordingly been withdrawn to its proper station on Alcatraz Island. With the view of placing the city and harbor of San Francisco in the best possible state of defense in case of a foreign war, I have, as you are already advised, caused reconnaissance to be made and sites selected for the erection of field-works. 1 found that our greatest embarrassment was likely to proceed from the want of heavy guns, and I accordingly addressed a communication to Capt. W. H. Gardner, U.S. Navy, commanding the navy-yard at Mare Island, on the subject. My ietter to Captain Gardner and his reply are both herewith inclosed.+ The eighty-nine guns which are placed at my disposal will materially aid us in making up the armament for the batteries. I propose to use every heavy gun I can command for the defense of this city and harbor. Although there are several points on the Pacific Coast that are exposed to capture by a hostile fleet, yet, in case of a war, San Francisco would first attract the enemy’s attention. The loss of San Francisco and harbor involves also the loss of our navy-yard and our military arsenal at Benicia. In fact, it destroys for the time all our commerce on the Pacific. Hence this place should be made impregnable.

Very respectfully, your obedient servast,