At this point the palisade was interrupted for an artillery redan, an earth structure designed to protect two cannons, with lower sections in its wall showing where each gun muzzle would protrude. Of the roughly three dozen redans that once existed along the River Line, this is the only one that remains. The most common cannon used by both sides was a 12-pounder Napoleon, a smoothbore gun that lacked the range and accuracy of a rifled gun but could fire many types of ordnance, including shot, shell, grape, and canister, and could duel opposing artillery, shell enemy troops at a distance, or blast attacking infantry. A photograph taken by George N. Barnard shows a Napoleon in Atlanta's defenses while Federal troops occupied the city in September 1864, and that same cannon is now displayed in the Kennesaw Mountain National Battlefield Park Visitors Center, about ten miles northwest. Although the specific artillery unit that occupied this redan is not known for certain, all batteries assigned to this section of the River Line were equipped with 12-pounder Napoleons or 3-inch ordnance rifles.