SEPTEMBER 25-OCTOBER 13, 1864.-Expedition from Little Rock to Fort Smith, Ark., with skirmishes at Clarksville (September 28), at White Oak Creek (September 29), and at Clarksville (October 9).

Report of Major Thomas Derry, Third Wisconsin Cavalry.

LITTLE ROCK, ARK., October 14, 1864.

SIR: I have the honor to report that, in compliance with Special Orders, Numbers 2, paragraphs II and IV, headquarters Cavalry Division, Seventh Army Corps, I marched from Little Rock, September 25, with the following detachments under my command, to wit: Third Wisconsin Cavalry 141 men, 1 captain, 2 lieutenants, and 1 surgeon, with ambulance and medical supplies; Third Arkansas Cavalry, 1 captain and 50 men; First Iowa Cavalry, 1 lieutenant and 63 men; Third Missouri Cavalry, 1 captain and 64 men; Third U. S. Cavalry, 1 lieutenant and 50 men, with 9 men from the Fourth Arkansas Cavalry; in all, 7 officers, 377 men, 1 surgeon, 2 ambulances, and 2 wagons, but no surgeon with supplies from Second Brigade, as ordered. Having crossed the Cadron with much difficulty, the ferry-boats being destroyed, the command obtained the first forage since starting, forty miles distant, at Colonel Howard's, on September 26. Proceeding thence through Lewisburg I ascertained that the various parties f the enemy, scattered along the route, had been informed of the numbers of the command and the object of the march. Encamped on Illinois Bayou, where we found plenty of wood and water but scarcely any forage. On the 27th we camped six miles this side of Piney, where I learned that the commands of Colonels Hill, Stirman, and Brooks were at various points along the route with headquarters at Clarksville, at which place they intended to oppose me. The next day, 28th, soon after crossing the river, which I was obliged to do by making a long circuit, the ferries being all destroyed, the advance, under Captain Herring, Third Arkansas Cavalry, began to fall in with parties of the enemy and pursued them with much spirit. Approaching Clarksville about 3 p. m., Captain H. fell upon their pickets, who, after some resistance, fell back upon the main force in the town. The advance followed on rapidly, deployed through town, the enemy taking refuge behind fences and houses, the main column closely supporting them. The enemy fled in every direction, leaving 7 dead. Independent companies and rebel conscripting officers are very numerous and active in this vicinity, having Clarksville for a rendezvous. So long had they been advised of our coming that the citizens had letters written for us to carry to Fort Smith and Little Rock. We were not expected so soon by a day; our rapid marching took them by surprise, so their resistance was not so vigorous as it might otherwise have been. Camped three miles beyond Clarksville. We had scarcely halted when we were bushwhacked on all sides. skirmishers being sent out drove them off until dark. Attempts were being made all night, under cover of a severe storm, upon the pickets, but their alertness frustrated every attempt, though at daylight 1 man from the Third Wisconsin Cavalry was killed on his post. On the 29th skirmishing began with the march upon the front, both flanks, and rear. Having thrown out skirmishers on flanks these attacks were checked. Still firing was continuous without doing us much damage, the enemy suffering somewhat in wounded. Camped on White Oak Creek. While the sergeants were posting their