...sippi, which was strongly fortified and held by a force of not less than eighteen thousand (18,000) men. On the Atchafalaya, the water communications toward Red River were defended by strong works at Butte à la Rose, and on Bayou Teche by strong land fortifications near Pattersonville, called Fort Bisland, extending from Grand Lake on the right to impassable swamps on the left of the Teche Bayou...