[Illustration: The position of the Allied Armies immediately before their advance.] On 5th September 1914 the Allied armies were in the position in which General Joffre wished them to be. Let us look at the line which they then held. The 3rd Army (A) stretched from the Upper Meuse, south of Verdun, westwards to Bar-le-Duc, and facing it was the army of the Crown Prince. The 4th Army (B) was on its left, astride of the Upper Marne, looking north across the plain towards Châlons. Westwards to Sézanne[99] was the 9th Army (C), and facing it was von Buelow's army. Still farther to the west were the 5th French Army (D) and the British (E); while north of the Marne, moving towards the Ourcq, was the 6th French Army (F), which, all unknown to the Germans, had been organized in Paris, where it was safe from the prying eyes of their airmen. Later on we shall study the position of the Allied armies on the left wing (D, E, F) more closely. Before we do so, however, I will try to give you some idea of the kind of country in front of the French line. Let us imagine that you are travelling westwards from Verdun in early September. Leaving behind you the narrow vale of the Upper Meuse, you traverse an upland country of many ravines and much undergrowth, with here and there small woods and pastures. Then you cross a small stream, and, looking southwards, see the deep woods that stretch towards Bar-le-Duc. The road now rises, and to the northward is the plateau of the Argonne,[100] a long, low ridge of clay, which forms the natural bulwark of north-east France; west of it runs the Aisne and east of it the Aire, a tributary of the Aisne. A small river cuts its way through it in a deep furrow. A French writer says that if we leave out of account the lengthwise furrow through which the river runs, the plateau may be compared with a wave just when it curls and is about to break on the shore. The summits of the plateau range in height from about 450 feet to 1,000 feet. An extensive forest is always a bar to an invader. In the days when the English were conquering Britain, a very dense and trackless forest, 130 miles long by 30 miles broad, covered that part of South England between the North Downs and the South Downs which we call the Weald. For many years this forest prevented the South Saxons, who had occupied the coast, from pushing their conquests northwards to the Thames. In the same way the Forest of the Argonne checked early invaders of France from the east. No other part of France is so thickly wooded, and in its deep recesses wolves are still found. Two roads and one railway cross it from west to east; but otherwise there are only a few forest paths, which lead nowhere. This difficult region was the scene of desperate fighting during many months of the war.