At the time of Wilson's Raid, a substantial number of men belonging to Ferguson's Cavalry Brigade were in dismounted camp at Carthage AL. That's present-day Moundville. Can't cite a source for this, but it appears that as many as three hundred and possibly more were available for defense of Selma on April 2nd. These men fought the day before (April 1, 1865) at Ebenezer Church AL. Harrison could have been with this detachment in Alabama and just wasn't paroled, and he may have been detailed to some assignment apart from the dismounted camp or the main body which disbanded at Forsyth GA.