Numbers 4. Report of Captain George H. Thompson, Third Indiana Cavalry.

CAMP THIRD INDIANA CAVALRY, May 24, 1863.

LIEUTENANT: In compliance with instructions from headquarters First Cavalry Division, I left Aquia Creek with my squadron, on board the steamers Manhattan and Tallaca, on the evening of the 20th instant, and was landed at Moon's Landing, on the Potomac, near the mouth of the Wicomico River, at 11.30 a.m. of the 22nd, and proceeded immediately toward my destination, passing through Heathsville and Lancaster Court-House to Chowning's Ferry, where I bivouacked my command. The distance being much greater than I had anticipated (37 miles), the ferry was not reached until the night of the 22nd, and, in consequence, was compelled to wait until the morning of the 23rd ere I attempted to cross the Rappahannock, which at this point is 4 miles wide. The boats I found to be in a leaky condition, and, in order to render my crossing practicable, I was forced to repair them. I embarked 20 men in two boats, and proceeded to cross. During the passage, a boat containing 4 men was observed crossing to this side of the river, who, upon seeing us, turned their boat, endeavoring to escape. Pursuit was immediately made, and the boat reached the opposite shore; but we succeeded in capturing the only white man of the party, who, with his wife and four children, we brought with us. These persons were a portion of the party of the expedition expected to intercept. One hundred and thirty-two dollars in Confederate money was taken from possession of the man, which is herewith forwarded, together with the person. The prisoner claimed to be a refugee from the Confederacy.

About 11 a.m. I landed at Urbana, and immediately took the proper steps to capture the party expected, together with the mail. Owing to the grounding of the transports and their slow passage down the Potomac, and the distance which we were force to travel, I found myself too late to be successful, the travelers having left Urbana the day previous. While upon the opposite side of the Rappahannock, Lieutenant Shannon came suddenly upon and captured Lieutenant Hardy, of the rebel artillery. Having destroyed all the boats that could be found, and burned the bridge leading south from Urgana, we returned to the transports en route for Aquia Creek, arriving at 12 p.m. of the 23rd instant, and disembarking at daybreak the morning of the 24th. Upon arriving at the boats on our return, I found 3 men claiming to be deserters from the rebel army, and 1 man who claimed to be a refugee from Richmond. These, together with the others before mentioned, I brought with me and delivered at division headquarters.

I have the honor to report the capture of 15 horses by my command one of which has been turned over to General Pleasonton by virtue of order from corps headquarters, signed by Lieutenant G. A. Custer, aide-de-camp, and also that some of my own horses were broken down and abandoned during the march. To supply the places of these abandoned horses it was necessary to take horses found along the line of march. I also report the capture of 2 horses by Lieutenant G. A. Custer, aide-de-camp, who accompanied the expedition.

Very respectfully, your obedient servant,

GEO. H. THOMPSON,

Captain Company E, Commanding Squadron Third Indiana Cavalry.

Lieutenant G. S. TAYLOR, Adjutant Third Indiana Cavalry.