This was the end:  the horizon expanded.  From the heights conquered in fourteen days of fighting the Allies went down to the plateau of the Soissonnais; soon they would reach the Vesle and join hands with the troops who had retaken Soissons.  Among the numberless heroes of this second battle of the Marne, they who stormed the heights of the Orxois and either outflanked or crossed the valley of the Ourcq were the bravest of the brave and are entitled to the largest share of our gratitude.  The third act of the battle was played upon a terrain quite different from those preceding it.  The relief is considerably simplified.  The great plateau of the Ile de France, which is buried, as it were, under the accumulations of recent deposits, where erosion has worn gaps in the ridges of the Orxois, and hollowed out the deep ravines of the Tardenois, is reduced here to the substratum of hard limestone, almost entirely free from superimposed layers.  So that, instead of being an uneven, swampy district, the Soissonnais is a dry level table-land, where the streams flow underground through the layers of limestone.  A fertile district, too, for the surface is covered with a thin coating of loam, in which sugar-beets and cereals vie with one another in profusion of growth.

[Sidenote:  Valleys of the Vesle and the Aisne.]

[Sidenote:  Fertile slopes and valleys.]

However, the plateau is intersected by occasional valleys, generally broad and deep.  The two most considerable are those of the Vesle and the Aisne which come together above Soissons, at Conde, and isolate the famous Chemin-des-Dames to the north.  Two tributaries, Ambleny brook and the Crise, flowing down to the Aisne, subdivide the southern portion of the Soissonnais, where the battle was fought.  With respect to the plateau, these valleys are little worlds apart.  Below the hard limestone, they have hollowed out a path through very soft rocks, sands, and clays; in these the streams have inevitably made large inroads, sapping the limestone cliffs which overhang them.  Thus the valley bottoms are abnormally wide—­from two to three kilometres near Soissons.  The presence of the clayey soils makes them very moist, and we find there fields of beets and grain side by side with extensive tracts of grassland.  On the lower slopes are many small fields given over to the less hardy products—­beans, orchards, and sometimes grape-vines.  Here are most of the villages, at the level where the water-courses, seeping through the limestone of the plateau, reappear in the shape of springs, on the impervious stratum.  For the most part the villages lie along the hillsides, surrounded by trees, embellished by chateaux and parks.  They are well-built and attractive, boasting churches of graceful architecture, thanks to the lovely decorative stone taken from the quarries in the limestone cliffs above, which are called boves, or croutes.  A fascinating, fertile country, diversified and pleasant to the eye, before the war it might well have been taken as a sample of rural opulence.