e 20th they forced their way into Etrepilly and
Chateau-Thierry.

[Sidenote: The terrain beyond is less rugged.]

Immediately beyond, the terrain is not so difficult. The Clignon valley
becomes less rugged and gradually blends with the plateau. Toward
Bezu-St.-Germain and Epieds lies a comparatively open plain with
extensive stretches of fallow land. In this more open region the
progress was more rapid; on July 22 the American troops took possession
of Epieds, twelve kilometres from Bouresches, their starting point.

[Sidenote: Along the valley of the Ourcq.]

But the difficulties are more serious farther to the north, along the
hills which form the southern boundary of the valley of the Ourcq.
Although the depression made by the Ru d'Alland, being broad and level,
is not a considerable obstacle, it is not the same beyond. The relief
map shows a line of heights running from west to east, and rising higher
and higher in that direction. From these heights a multitude of valleys
descend to the Ourcq, from south to north, cutting the crest into hills
separated by depressions. Thus the terrain is broken up in every
direction and well adapted to meet an attack from the west as well as
one from the south.

[Sidenote: The French carry ridges and valleys in succession.]

It was necessary to deal with all these obstacles one by one. Starting
from the west, the French had to carry successively these lines of
crests and depressions with their fortified villages: ridge of Monnes,
July 19; ravine of Neuilly-St-Front the same evening; the hill of
Latilly and its wood the 20th; La Croix and Grisolles the 21st, with
their thickets and dense plantations of osiers. On the 23d the Allied
troops took Rocourt and the wood of Le Chatelet; on the 24th the deep
ravine of Brecy; and, finally, on the 25th, French and Americans
together attacked the hill of the forest of Fere, which is 228 metres
high, completely covered with woods, cut by ravines, and flanked by
fortified villages. On the 27th the whole position was taken, and the
Allies were on the verge of the deep valley of the Ourcq, which they
were next to cross.

[Sidenote: Caves in the cliffs.]

[Sidenote: Allies turn the line of the Ourcq.]

This line was a by no means inconsiderable obstacle. Imagine, if you
please, a deep depression, twisting and turning in all directions, and
from 200 to 400 metres wide, extending at least as far as
Fere-en-Tardenois. It is bounded on either