I think Armstrong's Mississippi brigade opposed the advance by Long's 2nd Division. Don't know if the prisoners captured by the 4th Michigan belonged to that brigade. Here are some accounts:

Lt. Col. Pritchard, 4th Michigan cavalry, 2nd brigade, 2nd division: "I received a second order from General Wilson to move up the main road dismounted to charge the enemy's second line of works, from which a portion of our line had suffered a repulse. The regiment was formed for the charge about 60 rods in front of the rebel line, with its right resting on the road, with the 3rd Ohio cavalry on our right. The order to advance was given and most splendidly executed, the whole line moving with the precision of a parade, and the sturdy bravery thus displayed proved too much for the weak-kneed Johnnies, for before we reached the breast-works they broke and fled in the wildest confusion, leaving naught of the chivalrous garrison save a lame and decrepit chaplain to reward our efforts. I immediately broke the regiment in column and pushed forward at double-quick until we reached the heart of the city, where we succeeded in capturing 152 prisoners, and met the advance of the 4th division just entering the town from the other side" OR: Vol. 49, Part 1, Pg. 464

Lt. Col. White, 17th Indiana, 1st brigade, 2nd division: "We took during the fight about 300 prisoners, including most of the 1st Mississippi regiment and a large portion of the 10th Mississippi regiment, with the colonel, lieutenant colonel, major, and adjutant of the former regiment, Colonel White, of the 8th (9th) Mississippi, and a number of officers of inferior rank. The prisoners were sent to the rear, and were turned over to and picked up by various officers having charge of prisoners. We also captured the ordnance wagons of Armstrong's brigade (2 in number), destroyed the ammunition, and retained the wagons. We took into action 17 commissioned officers and 404 enlisted men." OR: Vol. 49, Part 1, Pg. 456