fired upon last evening between the pike and the railroad by a party of about ten men, and two of the patrol captured; the other two brought word to Annandale, and Colonel Leazelle sent out a party of forty men, under command of Lieutenant Tuck, Sixteenth New York Cavalry, in search of the attacking party. After having scouted through the country directed Lieutenant Tuck halted his party about one and a half miles beyond Centreville to feed. While the horses were feeding a party of rebels, reported to number about sixty, dashed in upon them. Our party made no stand, and Lieutenant Tuck reports his men as appearing demoralized and panic stricken, scattering in all directions. Lieutenant Tuck is the only one of the party who has as yet (6 p. m.) reached camp, the remainder being either wounded, prisoners, or straggling.

After Lieutenant Tuck had been sent out a citizen reported to Colonel Lazelle that he had been stopped by Mosby last evening near Centreville, and detained under a small guard till morning, and that small parties had been by him along the roadside for a miles or more, appearing to number in all about 100 men. On receipt of this intelligence Colonel Lazelle sent out 150 men, under Major Nicholson, to support Lieutenant Tuck. This party started at 8 a. m., at 2 p. m. Lieutenant Tuck himself returned, reporting attack as above at 11 a. m. He was at once started out by Colonel Lanzelle with a party of fifteen men to overtake the party of 150, and put them on the trail and follow them as far as Aldie. Major Nicholson is still out. A party of 100 men, under Major Forbes, with ambulances, has been sent out from here this evening to the place of the surprise, to pick up stragglers and horses and any wounded men that may be there, and to support Major Nicholson if Mosby is reported by the citizens of Centreville to have had more than the sixty men. Some of our men will probably straggle in during the night.

I have considered it useless to start in direct pursuit Mosby, who had fourteen miles and at least six hours start of any party from here. The roads are so dusty that a pursuing party would be seen for miles and miles, and time given to hide or to escape.

Lieutenant Tuck's written report of the affair will be forwarded as soon as received.

Very respectfully, your obedient servant,

C. R. LOWELL, JR.,

Colonel Second Massachusetts Cavalry, Commanding Brigadier

Lieutenant Colonel J. H. TAYLOR,

Assistant Adjutant-General, Department of Washington.

HEADQUARTERS CAVALRY BRIGADE,
Near Falls Church, Va., June 25, 1864-11 a. m.

COLONEL Major Forbes has just returned from Centreville, and I am able to sent a clearer account of Lieutenant Tuck;s affair. It seems that Mosby came down on Thursday evening to near Union Mills with about 200 men and an iron gun drawn by six horses. Thursday p. m. a small squad of Kincheloe's men took two of Colonel Lazelle's patrol, as reported last night. When Mosby with a few men came down to spy out the land, he learned this, and concluded that there would be too much stir for him to carry out his plan, whatever it was. He returned, therefore, to Union Mills Friday