although their line was visible from the signal station at Fort Reno, the long-range guns of the fort could not be brought to bear upon them without endangering our own men. Colonel Lowell transmitted from time to time accurate and reliable information of the enemy's numbers and movements. About 11 a. m. the infantry pickets between the Rockville and River roads were driven in, but were promptly strengthened and advanced. About the same time the enemy showed signs of shifting to our right, and during the entire afternoon could be seen of shifting to our right, and during the entire afternoon could be seen (by the aid of a glass) moving in large force toward the Seventh-street road. Their intention was so apparent that orders were at once issued to mass troops rapidly on the right, and at 2p. m. when skirmishing commenced at Forts Stevens and De Russy, the movement was accomplished. For a detailed account of the operations in that vicinity, I respectfully refer you to the accompanying report of Colonel John M. C. Marble, One hundred and fifty-first Regiment Ohio National Guard, who was assigned to command at this point.

On Tuesday, the 12th instant, Colonel Lowell was sent out on the River road with two squadrons of his own regiment, while Lieutenant-Colonel Crowninshield with about the same force operated in the enemy's front on the Rockville road. By a preconcerted arrangement, Colonel Lowell attacked the enemy's right, while Lieutenant-Colonel Crowninshield attacked in front, forcing them back about a mile and a half, the enemy throwing away arms, equipments, and retiring in great confusion. Major Fry relieved Lieutenant-Colonel Crowninshield on the Rockville road about dark, and strong cavalry pickets were placed on the Rockville, River, and Aqueduct roads. On the same night from information given by Colonel Lowell, and reports of Colonel John M. C. Marble, commanding at Fort De Russy, the troops were transferred to our extreme left and massed at Forts Simmons and Sumner.

On Wednesday morning, the 13th, Colonel Lowell's cavalry force, about 900 strong, was pushed out as far as Rockville. Here a sharp encounter occurred, in which we were driven back with some loss, but held a position at night about a mile and a half this side of the town.

On the following morning, the 14th, the enemy had entirely disappeared from our front. During the entire period in which these events transpired, I am greatly indebted to Colonel C. R. Lowell, jr., commanding cavalry, who early succeeded in developing the enemy's force, which proved to be General McCausland's brigade, composed of the Tenth, Fifteenth, Nineteenth, and Twenty-second Regiments of West Virginia Cavalry and two regiments of Jackson's old brigade; in all about 1,500 strong, with two pieces of artillery. Colonel John M. C. Marble, commanding at Fort De Russy, and Captain L. A. Dillingham, One hundred and twenty-second Regiment New York Volunteers, signal officer, contributed valuable information. Colonel Gile's brigade of Veterans were conspicuous for conduct in the skirmish of 12th instant.

I inclose herewith a report of casualties,* a record of artillery practice, also Colonel Marble's report, to all of which your attention is respectfully called.

J. M. WARNER,

Colonel First Vermont Artillery, Commanding.

Captain R. CHANDLER, Assistant Adjutant-General.

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*Nominal list (omitted) shows 11 wounded.

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