The casualty list of the Marine Corps amounted to about 6,000, of whom only 57 were captured by the enemy. They lost approximately half of their numbers who entered battle. But they took more prisoners than they lost, all told, of their own men, and they inflicted more casualties than they received. The big guns sent by the Navy to France for land warfare played an important part in the decisive battles of the last few weeks of the war. These huge, 14-inch guns, 66 feet long, had been intended originally for the new battle cruisers, but a change of ship design had made them available for other uses and the Navy Bureau of Ordnance suggested that they be put on railway mounts and used on land. They were first offered to the British authorities for use behind their lines, but they doubted the effectiveness of the guns and delayed final answer until General Pershing asked for them. At the end of December, 1917, not a drawing for the mounts had been started. Four months later one of the guns was rolling on the wheels of a completed mount for long range tests at the Sandy Hook Proving Ground. At the end of hostilities forty-four guns and mounts had been sent over in various steps of preparation for the front and six of the monsters had been in action, throwing their destructive shells far behind the German lines. The railway mounts, designed for this particular purpose, were built and covered with armor plate by the Navy according to plans and designs prepared by its Ordnance Bureau, while the locomotives and the twelve cars for the operating forces of each gun, including berth and kitchen cars, armored ammunition cars, machine shop cars containing everything from a forge and anvil to a handsaw, crane and wireless cars, were all built and equipped especially for the purposes of these land batteries of naval guns. Intensive training was given to the men, all of them taken from naval forces, who would operate the huge batteries in France and serve the guns in action. The whole battery was so mobile that even if it were in action when the order came to move, the gun, personnel and entire train of cars could be put under way in an hour. The first gun to be sent landed in France in the latter part of June but did not go into action against the enemy until mid-September, when, placed near Soissons, it fired on the railroads entering Laon. It had been intended for use against the German “Big Bertha” that had been dropping shells upon Paris from a distance of over seventy miles, but on the day in August when the American gun was ready to begin action “Big Bertha” retired and was heard of no more.