ux
and Trilport, although one or two Divisions were still north of that
river and west of the Ourcq. From the fact that the rearguards of both
my 1st and 2nd Corps in their retirement on the day previous were
slightly engaged, whilst a few outpost affairs were reported as having
occurred in the night, I judged the enemy to have got some distance
south of the Grand Morin River. The appearance of hostile cavalry
detachments on the previous evening indicated the presence of that
arm.

Whilst it appeared to me that our dispositions promised great things,
I also realised fully that the situation demanded the utmost care and
watchfulness, as everything depended on the timing of our movements,
the utmost measure of mutual support, and the most vigorous
and continuous attacks.

The area in which the British Army operated in the Battle of the Marne
may be described as the country enclosed between the tributaries of
the Marne, the Ourcq on the north and the Grand Morin on the south,
between which boundaries it is intersected by the Marne itself, and a
third tributary, the Petit Morin.

This area forms the western portion of the Plateau de la Brie, which
rises to a height of 400 to 500 feet above the plain of Champagne. The
general slope of the ground is from east to west. The plateau is of
rock formation, and the rivers, which were formerly of greater volume
than at present, have worn away deep channels, with the result that
the ground falls very steeply to the river-beds. A certain amount of
alluvial deposit has been brought down by the rivers and streams, in
the immediate vicinity of which are to be found marshy pools and
swamps. With the exception of the Foret de Crecy, to the south-west of
the area under consideration, there are no extensive woods, the higher
ground being covered with small copses of thick undergrowth with a
sprinkling of oak.

The country generally is open, and presents no obstacles to the
passage of troops of all arms. The steep cliffs rising abruptly from
the river-beds afford good defensive positions suitable for rearguard
actions, obliging an advancing force to concentrate at defiles.

The roads and railways follow generally the course of the rivers.

The chief roads are--

(_a_) Paris--Meaux--La Ferte-sous-Jouarre, where one branch continues
through Montmirail to Chalons, and the other bends slightly
north through Chateau-Thierry and Dormans to Rheims and Epernay.

(_b_) Paris--Lagny--Coulomm