Lying in the angle of the Rhine between Lake Constance and Strasburg is a mountainous region known as the Black Forest, which takes its name from the dark foliage of its pine timber. The general shape of the Black Forest is that of a triangle; its base resting on the Rhine between Lake Constance and Bâle, and its apex pointing north. Its total length is ninety-three miles; its breadth varies from forty-six to thirteen miles, and its average elevation is about three thousand feet. On the south and west sides the mountains are rugged and steep, but on the east side they descend gradually to the lower level of the adjacent country. Within its limits the Black Forest presents an almost impassable barrier to an army attempting to enter Germany from France. A few roads lead through it; but they lie in the fissures of the mountains, and are therefore difficult for the passage of troops. Extending into the Black Forest opposite Strasburg is the Kinzig Valley, and opposite Brisach are the Höllenthal (valley of Hell) and the valley of Waldkirch. At Bâle the valley of the Rhine is narrow, but at a short distance below that point it begins to widen till it reaches a breadth of fifteen miles. Good roads extend along the Rhine on both sides, and bridges span the river at Bâle, Strasburg, and Mayence. The opposing armies were thus stationed: Moreau's right wing, twenty-nine thousand strong, commanded by General Lecourbe, was in Switzerland along the Rhine from Lauffenberg to Lake Constance. Next on the left was the reserve of twenty-six thousand, commanded by Moreau in person; it occupied the intrenched camp at Bâle and extended some distance along the Rhine both above and below the city. The centre, consisting of thirty thousand soldiers, under General St. Cyr, joined the left of the reserve near Brisach, and stretched north almost to Strasburg. The left wing, nineteen thousand strong, under General Ste. Suzanne, occupied Strasburg and the bridge-head of Kehl on the opposite shore. Besides these forces, about twenty-six thousand were occupying Switzerland and the frontier fortresses of France along the Rhine as far north as Mayence.