 With this force, numbering about 7,200, Cornwallis first chased after the army of the Marquis de Lafayette, a much smaller force of Continental Army and local militiamen that had provided some resistance to the movements of Phillips and Arnold.Cornwallis was eventually ordered by General Clinton to establish a fortified deep-water port at either Yorktown or Portsmouth.Cornwallis chose Yorktown, and began constructing fortifications there and Gloucester Point, just across the York River from Yorktown, in August 1781.