standpoint, was a highly useful general survey of topographic features
and was widely used by officers and others.

GEOLOGY AT THE FRONT[63]

Perhaps the most spectacular and the best known use of geology in the
war was at and near the front. This use reached its earliest and highest
development in the German army, but later was applied effectively by the
British and British Colonial armies, and by the American Expeditionary
Force.

One of the first intimations to the American public of the use of
geology at the front appeared in the publication of German censorship
rules in 1918,--when, among the prohibitions, there was one forbidding
public reference to the use of earth sciences in military operations. A
leading American paper noted this item and speculated at some length
editorially as to what it meant.

It was discovered that geologists to the number of perhaps a hundred and
fifty were used by the Germans to prepare and interpret maps of the
front for the use of officers. Features represented on these maps
included topography; the kinds of rocks and their distribution; their
usefulness as road and cement materials; their adaptability for trench
digging, and the kinds and shapes of trenches possible in the different
rocks; the manner in which material thrown out in trenching would lie
under weathering; the ground-water conditions, and particularly the
depth below the surface of the water table at different times of the
year and in different rocks and soils; the relation of the ground-water
to possibilities of trench digging; water supplies for drinking
purposes; the behavior of the rocks under explosives, and the resistance
of the ground to shell-penetration; the underground geological
conditions bearing on tunnelling and underground mines; and the
electrical conductivity of rocks of different types, presumably in
connection with sound-detection devices and groundings of electric
circuits. Some of the captured German maps were models of applied
geology. They contained condensed summaries of most of the features
above named, together with appropriate sketches and sections. During the
Argonne offensive by the American army the captured German lines
disclosed geologic stations at frequent intervals, each with a full
equipment of maps relating to that part of the front. From these
stations schools of instruction had been conducted for the officers in
the adjacent parts of the front.

The British efforts were alo