On the backside of his March 18, March 20 letter, Chatfield sketched the map shown above. His drawing shows the Louisiana and Mississippi locations of his regiment, the railroad, the canal, landings, gunboats, levees, mortar batteries on DeSoto Point, batteries on Warrenton, and his December position on the Chickasaw Bayou delta below Walnut Hills. Although drawn without the benefit of surveyor's equipment or formal cartographer's training, Chatfield's sketch is remarkably similar to strategic military maps of the time. As he put it humbly, "This is a rough representation of the positions of the country around here and how we are situated."