he rivers of Southwestern Belgium on the other. On the
southern face of this watershed, the general trend of which is from
east-southeast to west-northwest, the ground falls in a series of long
irregular spurs and deep depressions to the valley of the Somme. Well
down the forward slopes of this face the enemy's first system of
defense, starting from the Somme near Curlu, ran at first northward for
3,000 yards, then westward for 7,000 yards to near Fricourt, where it
turned nearly due north, forming a great salient angle in the enemy's
lines.

Some 10,000 yards north of Fricourt the trenches crossed the River
Ancre, a tributary of the Somme, and, still running northward, passed
over the summit of the watershed, about Hebuterne and Gommecourt, and
then down its northern spurs to Arras.

On the 20,000-yard front between the Somme and the Ancre the enemy had a
strong second system of defense, sited generally on or near the southern
crest of the highest part of the watershed, at an average distance of
from 3,000 to 5,000 yards behind his first system of trenches.

[Sidenote: German methods of making position impregnable.]

During nearly two years' preparation he had spared no pains to render
these defenses impregnable. The first and second systems each consisted
of several lines of deep trenches, well provided with bomb-proof
shelters and with numerous communication trenches connecting them. The
front of the trenches in each system was protected by wire
entanglements, many of them in two belts forty yards broad, built of
iron stakes interlaced with barbed wire, often almost as thick as a
man's finger.

[Sidenote: Veritable fortresses.]

[Sidenote: Machine-gun emplacements.]

The numerous woods and villages in and between these systems of defense
had been turned into veritable fortresses. The deep cellars, usually to
be found in the villages, and the numerous pits and quarries common to a
chalk country were used to provide cover for machine guns and trench
mortars. The existing cellars were supplemented by elaborate dugouts,
sometimes in two stories, and these were connected up by passages as
much as thirty feet below the surface of the ground. The salients in the
enemy's lines, from which he could bring enfilade fire across his front,
were made into self-contained forts, and often protected by mine fields,
while strong redoubts and concrete machine-gun emplacements had been
constructed in positions from which he coul