SIGNAL OFFICE, July 13, 1863.

General ELZEY:

Dix with his entire army has fallen back to Fort Monroe, with the exception of Getty's division and the usual force at Yorktown and Williamsburg (about a brigade). This "On to Richmond army" has gone up to re-enforce Meade's.

Getty's division numbers about 8, 000, and, from the best information I can gather, is to return to the south side of James River. Also Spear's cavalry.

C. H. CAUSEY,

Captain, C. S. Army.

HDQRS. THIRTY-SECOND BATTALION VIRGINIA CAVALRY,
Bradley's Farm, July 13, 1863.

Captain J. H. PEARCE,

Assistant Adjutant-General:

CAPTAIN: Dispatch 8 p. m. just received. Lieutenant Dorsett, just returned from Wilcox's Wharf, reports two monitors, two mortar gunboats, seven wooden gunboats, and no transports. Two monitors passed a little above Westover this evening about 4 o'clock, and soon after went down the river to the fleet at Wilcox's. On the reconnaissance of the monitors, the signal post, I understand, was left by those in charge of it, but since the boats went down it has been reoccupied. Lieutenant Dorsett reports that no disposition to land was manifested; till this time no landing has been made. I have received no communication from the signal corps since located here. I have a picket as well as scouts watching the enemy at Wilcox's. I will endeavor to render the courier line efficient, and have dispatches forwarded promptly.

Very respectfully, your obedient servant.

J. R. ROBERTSON,

Major, Commanding.

COMMANDANT'S OFFICE,

Drewry's Bluff, Va., July 13, 1863.

Major General ARNOLD ELZEY,

Commanding Defenses, Richmond:

GENERAL: For fear you may not have received my telegrams, I send you copies of those sent you, as they came in this morning. We have now open communication by water line and by the wires, and every dispatch is sent to General Wise and Colonel Maury as soon as received, and, in order that you may not be uneasy about us, I will send you copies also.

Very respectfully, your obedient servant,

S. S. LEE,

Commandant.

[Inclosures]

JULY 13, 1863.

Captain S. S. LEE:

The enemy's fleet has passed up. The advance gunboat is 3 1/2 miles above Lower Brandon. Three monitors in the fleet.

[D. M.] HARKEY,

Lieutenant.