An iron, 6.4-inch US Navy Parrott rifled cannon. Markings on the breech of the cannon identify it as "R.P.P. No. 331" (possibly a reference to the initials of Robert Parker Parrott, the inventor of the cannon) with a weight of 9,747 lbs. A plaque in the cement sidewalk below the back of the cannon describes it as a "Civil War Artillery 6.4-inch (100 pounder) Navy Parrott Rifle. Donated in 1897 by the Grand Army of the Republic." The cannon mouth points south and pivots on a trunnion marked "1864 100 Pdr". The cannon muzzle is engraved with the words "Water Core".