HEADQUARTERS ARMY OF THE POTOMAC,
Camp near Alexander, Ny. June 21, 1863.

SIR:

I have the honor to submit the following report of operations of the First Section, Department of New York Signal Corps, of the Army of the Potomac, Captain Mark C. Williams commanding, as in relation to the recent movements and battles in New York on the 18th of June through the 20th of June 1863.

On Friday, 18th day of June, 1863, the First Section, Department of New York Signal Corps, of this army had, after some delays in transportation, arrived at Alexander from the Buffalo area camp. That evening, reports of southern troop movements by the 155th NY Vol. Inf. pickets, were reported on the high ground to the west of our position.

On the night of 18th June, two signal parties were reported for duty at Alexander. Dark skies with no moonlight afforded close observance from the most southern valleys of amassed confederate troops along the western ridge. Observed entrenchments extending from the southern ridge, as far as could be seen, to the west were reported by immediately, confirming the reports from the 155th, utilizing lantern night signals under the command of Captain Mark C. Williams, First Section, Department of New York Signal Corps.

No confederate artillery pieces were observed; breaks within the trench lines could be seen and noted as possible areas of confederate battery positions not yet deployed.

Union command was notified of the activities, reinforcements from both the 140th, and the 44th Inf., stationed to the East, and the Artillery and Calvary forces to the north were ordered to converge to our position at daybreak by courier should an attack be deemed necessary.

Further confederate entrenchment work continued throughout the night hours observed from within telescopic range, from the positions previously reported. Signalmen were deployed on rotating duty to provide an opportunity for rest and re-equipment of the signal parties for daylight deployment.

At daybreak, on Saturday, 19 June, the massive entrenchment could be seen, without telescopic assistance, a confederate signal tower was observed to the south center of the high ground crest.

Arriving reinforcement from the East and North were ordered by General command to set-up encampment within the wooded area, out of view of any confederate observance, and held in reserve incase of confederate movement.

Throughout the morning, the confederate signal tower was left unmanned. Skirmishers from the 155th were deployed to the entrenchment with one artillery battery for support. The entrenchment line was observed from vantage points to the north and south of the line for areas of weakness. Returning artillery fire, and strong inf. support, showed strong numbers, and no noticeable vulnerability.

Heavy Union artillery fire to the center of the line continued for several hours. The 155th was again deployed at just after noon for a direct line center attack on the entrenchments. Strong resistance from the confederate flanks held off any advancement. Our signal position on the north end was compromised by a small group of confederate skirmishers.

Advancement was held off by gunfire from our signal party and picket line from the 140th to the north. No casualties were reported. Five confederate Skirmishers were taken prisoner and questioned.

The southern end of the line suffered strongly. A confederate cavalry unit charged the union artillery line, 10 men and one gun were reported lost. The confederate suffered even greater losses. Captain Williams was last seen to send a message announcing the near approach of the enemy, and to then furl his flags as if to leave the station. There is unofficial information that he left the flank of the mountain, encountered and captured when near its base a courier with dispatches, by the enemy's cavalry. It seems probable that the first official information of the enemy's cavalry at that place. The enemy at once occupied the mountain with infantry and artillery, and held it.

Union retreat to the west, out of confederate artillery range, then proceeded without further incident. From the captured dispatches, it had become evident to the generals commanding, that the enemy reinforcements were passing the village of Darien from the east crossing eastward with additional provisions, telegraphic communications, confederate signals, and additional artillery.

On the evening of 19, June, additional supplies arrived along with the Union Calvary equipped with Henry repeating rifles. Orders for an assault on the confederate entrenchment for the morning of Sunday 20th June, prior to confederate reinforcement arrival, expected on the 22nd, were planned throughout the evening. All signaling that evening were ordered suspended, and further withdraw of the 155th was ordered to the wooded area south of the entrenchments.

On Sunday, 20th June, the signal parties of the First Section, Department of New York, Signal Corps, under the immediate charge of Captain M. C. Williams, with his aid Signal Lieut. Mark C. Hageman under whose supervision the stations of observation had been established, were issued. It was the plan of

the signal stations ordered this day that the general commanding the army should be enabled to receive on the field reports from the valley by the stations at Points on flanks by a station established on some commanding eminence in that valley.

The first objective to be to weaken the enemy center with artillery fire and destroy the confederate signal tower positioned there. Confederate troop movements to each flank were to be reported by each flanking station and held back by the 140th and 44th Inf. with Calvary support on both flanks after another frontal assault by the 155th through the center. Field Inf. movements were to be coordinated by bugle calls of the 44th, under the commander's direction, upon receipt of signal field reports.

Heavy Union artillery fire began precisely at 11:00 on 20, June. The third volley hit the confederate signal tower, it could be seen burning and shortly afterwards collapsed. No confederate communications were ever observed nor evidence that any confederate signals were present on any day from the 18th to the 20th of June.

As the 155th again made a charge to the confederate center, a confederate flanking attack was observed and reported from both sides of the entrenchment. Both sides were held by union Inf. and Calvary, now armed with Henry repeating rifles. Orders issued were to conserve fire with the Henry's, and utilize company fire, in conjunction with Inf. musket fire only, unless under heavy confederate fire.

Upon the forth volley of Union company musket fire, both confederate flanks charged, only to be held fast by the surprise continuous repeating rifles of the Calvary. Three surges by the 155th finally took the breast works of the confederate entrenchment and all enemy artillery fire upon Union forces was halted.

By 3:00 on 20, June the entrenchment was all but destroyed, the flag of the Union was seen fling from every vantage from the mountaintop.

On Monday, 21 June, following the retreat of the enemy commenced the advance of the army through the pass in the East and toward South. Early in the morning the course of the enemy's retreat and the positions they would select were uncertain. Officers were sent to the summit of the Genesee Ridge with instructions to select stations, and also to examine and report their observations of the country upon all sides. A careful examination was made from the high peaks of the gaps, which overlooks all the valleys between the North and South Mountains.

As a summary of the operations of the corps as connected with this campaign, I have to report that these operations have extended throughout Western New York. From before the departure of this army from Washington to the present time, the country in which it was to operate, or through which it was to pass, has been always under observation from some of these positions. The duties of the signal officers require that their watchfulness and reports should embrace occurrences in the night equally with those in the day. In each of the engagements of the campaign, officers of the corps have taken some part. They claim to have announced the entry of the enemy into New York, and of his retreat southward.

Of the value to this army of the watchfulness of these officers, of their observation, and the consequent reports made by them, and of their transmission of intelligence, the general who commands the army can best judge. Of the zeal with which the officers have tried to aid have undergone hardships few officers are required to meet, it is my duty to make mention.

I am, very respectfully, your obedient servant,
MARK C. HAGEMAN, Signal Officer, and Lieutenant
First Section, US Signal Corps Department of New York