Reconnaissance of the secession works at Yorktown, Va. made by Lieut Abbot, Topl. Eng'rs. and at Gloucester, Va. made by Lieut. Comstock, Eng'rs., May 4, 1862. For Gen. J.G. Barnard ... (with) Sketch exhibiting the position of Yorktown with the approaches from reconnaissance and survey between the 5th and 10th of April 1862. By command of Maj. Gen. Geo. B. McClellan ... A.A. Humphreys ... Reconnaissance of Red Redoubt Group to right of Yorktown made by Lieut. N.G. Hall ... (with) The position of Yorktown with the approaches from reconnaissances and surveys made by command of Maj. Gen. Geo. B. McClellan ..., prepared under the direction of Maj. A.A. Humphreys ... April 21st 1862. Julius Bien & Co., Lith., N.Y. (1891-1895)
