Fort Jackson, on the south or left bank of the river, was a casemated pentagon of brick, mounting in the casemates fourteen 24-pounder guns, and ten 24-pounder howitzers, and in barbette in the upper tier two 10-inch columbiads, three 8-inch columbiads, one 7-inch rifle, six 42-pounders, fifteen 32-pounders, and eleven 24-pounders, in all sixty-two guns. The water battery below the main work was armed with one 10-inch columbiad, two 8-inch columbiads, and two rifled 32-pounders. Fifty of these pieces were available against the fleet, but of the whole armament of one hundred and nine guns, fifty-six were old 24-pounder smooth-bores. The passage of the forts had been obstructed by a raft or chain anchored between them. The forts once overcome, no other defence remained to be encountered until English Turn was reached, where earthworks had been thrown up on both banks. Here at Chalmette, on the left bank, it was that, in 1815, Jackson, with his handful of raw levies, so signally defeated Wellington's veterans of the Peninsula, under the leadership of the fearless Pakenham. Fort St. Philip stands about 700 yards higher up the river than Fort Jackson; the river at this point is about 800 yards wide, and the distance between the nearest salients of the main works is about 1,000 yards. A vessel attempting to run the gauntlet of the batteries would be under fire while passing over a distance of three and a half miles. The river was now high, and the banks, everywhere below the river level, and only protected from inundation by the levees, were overflowed. There was no standing room for an investing army; the lower guns were under water, and in the very forts the platforms were awash. When the fleet was ready, Butler embarked eight regiments and three batteries under Phelps and Williams on transports, and, going to the head of the passes, held his troops in readiness to co-operate with the navy. On the 16th of April the fleet took up its position. The mortar-boats, or "bombers," as they began to be called, were anchored between 3,000 and 4,000 yards below Fort Jackson, upon which the attack was mainly to be directed. From the view of those in the fort, the boats that lay under the right bank were covered by trees. Those on the opposite side of the river were screened, after a fashion, by covering their hulls with reeds and willows, cut for the purpose. On the 18th of April the bombardment began. It soon became evident that success was not to be attained in this way, and Farragut determined upon passing the forts with his fleet. Should he fail in reducing them by this movement, Butler was to land in the rear of Fort St. Philip, near Quarantine, and carry the works by storm. Accordingly, he remained with his transports below the forts, and waited for the hour. Shepley occupied Ship Island with the rest of the force.