General Sarrail was well aware that if the great howitzers of the Germans were once permitted to come within range of the forts they would succumb as speedily as those of Liége, Namur, and Maubeuge. He therefore pushed out his circle of defences for twenty miles from the city. By means of earthworks and trenches he made a great fortified zone, which encircled the forts at such a distance that the German howitzers were kept out of range. Every height and valley was seamed with defences, and some of the hillsides became a maze of barbed wire. The heavy guns of the forts were moved out to the advanced trenches, and rails were laid down so that as soon as they were "spotted" they could be moved on to another position. Thus, instead of fixed forts, each, say, mounted with ten heavy guns, these same ten heavy guns were "dotted here and there in trenches rapidly established in one place and another, along perhaps half a mile of wooded vale, and free to operate when they moved over perhaps double that front." The result was that the army of the Crown Prince found itself held up in the form of a semicircle, as shown in this diagram. Against these outer lines of defence seven German army corps were launched, but with no success. [Illustration] In the third week of September the Bavarian army made a determined attack on the little town of St. Mihiel,[139] which stands on the Meuse, midway between Toul and Verdun. North to Verdun and south to Toul, between the Meuse and the Moselle, is the district known as "the Plain of the Woëvre."[140] It is crossed by the Heights of the Meuse, which form a plateau about three hundred feet above the river, and fall steeply towards the east in deep ravines and wooded knolls. On 20th September the Bavarians pushed through the Woëvre and drew near to the Meuse. Two forts blocked their way, one of them being on the site of an old earthwork known as the Camp of the Romans. The Bavarians got their heavy guns into position, and by the evening of 22nd September the Camp of the Romans was in ruins. The garrison, however, made such a gallant resistance in the outer works that the German general permitted it to retire with the honours of war. As the French marched out of the fort the Germans cheered them, presented arms, and dipped their flags. Shortly afterwards the Bavarians seized St. Mihiel and its bridgehead,[141] on the western side of the water. A French cavalry detachment prevented them from advancing any further, and they were forced to entrench themselves on the edge of the river. [Illustration]