The movement began on our side only with the resources of the army which
had held the left of our front during the battle of the Marne,
reinforced on Sept. 15 by one army corps.
This reinforcement, not being sufficient to hold the enemy's offensive,
(district of Vaudelincourt-Mouchy-Uaugy,) a fresh army was transported
more to the left, with the task "of acting against the German right wing
in order to disengage its neighbor, ... while preserving a flanking
direction in its march in relation to the fresh units that the enemy
might be able to put into line."
To cover the detrainments of this fresh army in the district
Clermont-Beauvais-Boix a cavalry corps and four territorial divisions
were ordered to establish themselves on both banks of the Somme. In the
wooded hills, however, which extend between the Oise and Lassigny the
enemy displayed increasing activity. Nevertheless, the order still
further to broaden the movement toward the left was maintained, while
the territorial divisions were to move toward Bethune and Aubigny. The
march to the sea went on.
From the 21st to the 26th all our forces were engaged in the district
Lassigny-Roye-Peronne, with alternations of reverse and success. It was
the first act of the great struggle which was to spread as it went on.
On the 26th the whole of the Sixth German Army was deployed against us.
We retained all our positions, but we could do no more; consequently
there was still the risk that the enemy, by means of a fresh afflux of
forces, might succeed in turning us.
Once more reinforcements, two army corps, were directed no longer on
Beauvais, but toward Amiens. The front was then again to extend. A fresh
army was constituted more to the north.