Before the general attack which took place on that _dies irae_, September 29, the Americans had a brisk fight of their own, which deserves some special mention as it was the first large operation of an American force acting as part of a British Army. The Second American Army Corps (General Read) had been specially selected to lead the attack on September 29, and as a preparation for this great effort they were ordered to make some advance along their whole front in order to gain an advantageous point from which to start. They lay roughly along {151} the front of the Hindenburg outpost line, but they needed to draw up closer to the main line before the day of battle. On the night of September 24, General O'Ryan's Twenty-seventh American Division from New York on the left relieved the Eighteenth and Seventy-fourth British Divisions, taking over a front of 4500 yards opposite to Gouy. The defences immediately before them were particularly strong, including the notorious danger points, the Knoll, Quinnemont Farm, and Guillemont Farm. The 53rd American Brigade (Pierce) took over the line, with the 106th Infantry Regiment in front and the 105th in support. The entire American front was from near Vandhuile in the north to Bellicourt in the south. The tunnel, which formed a special feature in the next great battle, deserves some description, as it was a remarkable feature dating back to the First Empire, and still bearing upon its arches the laconic N of the great Corsican. It is 6000 yards long and averages 50 feet below the surface, with a breadth of about 70 feet. The Germans had converted it into an extraordinary military work, for it was stuffed with barges in which a whole division could take absolute refuge from the heaviest barrage ever launched. There were all sorts of bolt-holes in every direction for getting in or out, and there were powerful machine-gun emplacements along the top. Altogether it was as awkward a nut to crack as any military engineer could conceive. The main Hindenburg Line lay a couple of hundred yards west of the tunnel, a heavily-wired system of trenches. About a mile farther east was a strong support line joining the villages of Nauroy and Le Catelet, while {152} two or three miles farther on was yet another strong position, known as the Beaurevoir line. The way in which Americans, Australians, and British combined with equal valour to hunt the Germans out of this terrific series of positions is a story which will go down in the common traditions of the English-speaking race.