Substantial trade towns and cities - Cahawba, Claiborne, Selma, Camden, and Demopolis - sprang up along the riverbanks to facilitate the shipping of Black Belt cotton through the port city of Mobile to supply the increasingly wealthy planters with incoming goods and services. During the early years, flat bottom boats, each carrying up to 100 bales of cotton, plied the waterways, but upstream travel was very difficult. Often after a downstream trip, these boats were dismantled and the lumber sold in Mobile, leaving the crew to walk home.