ns difficult.]

What is the nature of the terrain above those steep cliffs which enclose
the valley of the Marne? Does it become more favorable to military
operations than the deep depression through which the river flows? Not
by any means. The surface of the table-land is broken by so many ravines
and narrow valleys which descend steeply to the Marne, that it is cut
into a multitude of ridges and hillocks amid which it is no longer
possible to recognize the original horizontal aspect of the plateau.

[Sidenote: Heavy impermeable soil.]

[Sidenote: Hills that are fortresses.]

On the other hand, the strata which lie on the surface--loam, sandstone,
and clayey sand--make a heavy, impermeable soil, quite infertile, in
which it is hard to raise anything, and which is largely given over to
woods. Thus, freedom of movement is impeded by deep ravines, ridges
running in all directions, and more or less dense forests; an offensive
is difficult, and the defensive easy. This is true in the immediate
neighborhood of Chateau-Thierry, where the ravines of Vaux, Brasles,
Charteves, Jaulgonne, and Treloup, and the valley of the Surmelin, slash
the plateau on either side of the Marne into fragments--into
forest-topped hillocks which are genuine fortresses, where the struggle
was terrific and where the Allies were able to advance only one step at
a time: on Hill 204, west of Chateau-Thierry, in the Bois de Mont
St-Pere, the forest of Feze above Jaulgonne, and especially on the spur
of the forest of Riz; and south of the Marne, at the broad, wooded
bastion of Saint-Agnan and at La Chapelle-Monthodon, where the fighting
was so intense from the 15th to the 20th of July.

[Sidenote: The villages and forests of the table-land.]

[Sidenote: Genuine mountain battles.]

This strip of broken table-land becomes broader again farther upstream,
above Dormans and Chatillon-sur-Marne. In that direction the plateau of
the Ile de France ascends until it is more than 260 metres above the
stream. Erosion has been even more active there, and in that part of the
Tardenois the plateau is dissected into narrow strips separated by deep
valleys, broad and moist, the largest of which is the valley of the
Ardre. In the valley bottoms the streams are bordered by bands of
tillage land; above, on the lower slopes, amid the vineyards and
orchards which monopolize all the favorable exposures, is a multitude of
small villages, some of which have become famous--