by the road from Alexandria to Richmond, there to be joined by the whole movable force form northeast of the river, having landed from the Potomac, just below the mouth of the Occoquan, moved by land up the south side of that stream to the crossing point named, then the whole move together by the road thence to Brentsville and beyond to the railroad just south of its crossing of Broad Run, a strong detachment of cavalry having gone rapidly ahead to destroy the railroad bridges south and north of the points.

If the crossing of the Occoquan by those from above be resisted, those landing from the Potomac below to take the resisting force of the enemy in rear, or, if the landing from the Potomac be resisted, those crossing the OCCoquan from above to take that resisting force in the rear. Both points will probably not be successfully resisted at the same time.

The force in front of centreville, if pressed too hardly, should fight back lowly into the intrenchments behind them.

Armed vessels and transportation should remain at the Potomac landing to cover a possible retreat.

[Indorsement.]

Memoranda of the President on campaign of Potomac without date, but about December 1, 1861 ; and letter of General McClellan dated December 10, 1861.

WASHINGTON, March 3, 19862.

Major General H. W. HALLECK,

Saint Louis:

MY DEAR HALLECK:Yours of the 24th* arrived while I was up the river. I went there to superintend the passage of the river and decide as to the ulterior movements of the troops. The passage was a difficult one, but the Engineer troops under Duane did wonders. I found it impossible to supply a large body of troops without first establishing depots on the Virginia side, which we are rapidly doing. So I contented myself for the present with occupying Charlestown, &c., in order to cover the reopening of the Baltimore and Ohio Railroad. I have also occupied Martinsburg, and will to-morrow throw out a strong force to Bunker Hill. We are thus in position to attack Winchester as soon as our supplies are collected.

I hope to open the Potomac this week, provided the weather permits. It will require a movement of the whole army in order to keep Manassas off my back. I cannot count upon any effective co-operation on the part of the Navy. As soon as I have cleared the Potomac I shall bring here the water transportation now ready (at least it will be in four or five days), and then move by detachments of about 55,000 men for the asked for 50,000 men from here, my dear fellow, you have made one of two mistakes-either you have much overrated my force or you have thought that I intended to remain inactive here.

I expect to fight a desperate battle somewhere near Richmond, the most desperate of the war, for I am well assured that the Army of Manassas remains intact, and that it is composed of the best armed and best disciplined that the rebels have, with the prestige of Bull Run in their favor. I have or expect to have one great advantage over you,

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*Not found.

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