...a small boat. She was loaded with oysters, shad, cedar posts, carpet-bags, containing a quantity of clothes for the rebels, with a lot of letters, from which we learn that the rebels are evacuating Fredericksburgh , and talk of burning the town, to keep it from falling into our hands. At nine o'clock we got underway, and proceeded down the river to Corbin's Creek, to cut out some schooners which are in there,...