In the 1820s and 1830s, Georgetown was an important shipping center. Tobacco and other goods were transferred between the canal and shipping on the Potomac River. As well, salt was imported from Europe, and sugar and molasses were imported from the West Indies.[8] These shipping industries were later superseded by coal and flour industries, which flourished with the C & O Canal providing cheap power for mills and other industry.[12] In 1862, the Washington and Georgetown Railroad Company began a horsecar line running along M Street in Georgetown and Pennsylvania Avenue in Washington, easing travel between the two cities.