(Potomac River Route 2401) Potomac Steamboat Sep 7, red cds on folded cover docketed "New York 6 Sept / 50" to New Orleans La. bearing 10¢ black (2), large margins to barely touched, tied by manuscript "X" for the rate over 300 miles, sender endorsed "Paid" at lower left, docketed as received Sep. 16th, Fine. Towle No. G-21-a  Estimate $3,000 - 4,000. THIS IS THE ONLY RECORDED USE OF THE 10¢ 1847 ISSUE LEGITIMATELY USED ON THE POTOMAC RIVER ROUTE. There is a 10¢ 1847 issue bisect use recorded but was marked by the post office as "illegal stamp". $0 (Image)