Abattis or Abatis (Fr.) --
felled trees,
arranged in the form of a hedge with trunks aligned and anchored
in a
shallow ditch. Branches were sharpened and interlaced pointing
toward
the enemy. Its purpose was to prevent surprise and to delay an
attacking
force within range of defensive weapons. Sometimes called a
slashing.
Active Defense -- strategy of defending a
line by maneuver
and counterattack.
Advanced Works -- fortifications in advance
of
but still within firing range of the main works.
Angle -- where two faces of a fortification
meet. See
Salient and Reentering Angles.
Apex -- foremost salient angle of a
fortification,
that which protrudes farthest toward the enemy.
Approach -- a trench dug to get closer to the
enemy line,
called a sap in siege operations.
Artillery Strong Point -- a battery,
redoubt,
or bastion that served to anchor a larger system of
fortifications.
Artillery Works -- earthworks designed to
protect artillery
and to provide an effective field of fire.
Back-ditch or Interior Ditch
-- ditch
dug behind a parapet. See Ditch.
Banquette (Fr.) or Firing
Step -- a
shelf dug behind a parapet that allowed a defender to step up
from the
ground to fire over the parapet, then step back down under cover
to reload.
A banquette was only necessary when the parapet was higher than a
man's
armpits. It was a common feature associated with prepared
fortifications,
curtains, and detached works, such as redoubts. If
a banquette
survives, it is often blurred by soil eroding from the
parapet.
Balk -- a narrow barrier of earth within the
ditch of
an earthwork that was purposely left unexcavated. Balks
sometimes marked
divisions between units in the line. A balk might also serve as
the base
for a traverse made of logs.
Barbette (Fr.) -- artillery positioned to
fire over the
parapet rather than through an opening in it. See
Embrasure.
A cannon firing en barbette had an unrestricted
(180-degree) field
of fire, but its gunners were more exposed to fire than one
firing en
embrasure. A barbette gun was raised to fire over the
parapet by
means of a large carriage or by a gun platform built up to the
appropriate
height. See Gun Platform.
Bastion (Fr.) -- an angular work that
projected outward
from the main faces of a fortification. Its purpose was to
eliminate
defilade by directing fire along the front of an adjacent
curtain
wall. Like a lunette, a bastion consisted of four parts: two
faces
forming a salient angle oriented towards the enemy, and
two reentering
flanks that directed fire sideways across the faces of
adjacent
bastions. A curtain (or curtain wall) connected two or
more bastions.
See Lunette.
Bastion Line -- a series of bastions joined
by short
curtains.
Bastioned Fort -- an enclosed earthwork with
bastions
in the angles to provide fire along the fronts of the connecting
curtains.
Battery -- an artillery unit or a
fortification designed
to defend an artillery unit.
Berm or Berme (Fr.) --
narrow ledge
or shelf left at grade to separate the scarp of the ditch
and the
exterior slope of the parapet. When constructing
high-relief defenses,
workers stood on the berm to relay earth from the ditch up onto
the parapet.
The berm was sometimes left to retard slumping of the parapet,
but many
engineers felt that it assisted attackers in scaling the parapet
and had
it pared down after construction. Soil eroding from the parapet
will
typically blur a berm's outline.
Blockhouse -- building constructed of heavy
logs in
the shape of a square, rectangle, or cross, to serve as a strong
point
for infantry or artillery. A ditch was often excavated around the
exterior
with the spoil thrown up against the wooden structure as a
protection
against fire and gunfire. Often part of the first floor of a
blockhouse
was below ground, while the upper floor, pierced with loopholes
and embrasures,
was built with an overhang so that defenders could fire down
around the
base of the structure. Blockhouses were used to defend railroad
trestles,
bridges, and depots, or served as a "keep" or place of final
refuge in
a larger fortress or stockade. The excavations associated with
many blockhouses
survive, although timbers were often scavenged for other uses.
Some had
brick or stone flooring and fireplaces.
Bombproof -- a log or plank room or bunker
covered over
with earth to protect troops from artillery fire. A surviving
bombproof
appears as a large mound of earth, sometimes with an elongated
depression
in the top where underlying timbers have collapsed or in the side
where
the entrance used to be. See Magazine.
Bottom of the Ditch -- flat space at the base
of the
ditch that separated the scarp and
counterscarp.
Boyau (Fr.) -- a communication trench,
a sap pushed
forward toward the enemy. Typically constructed in a zigzag
pattern to
prevent exposure to direct fire from the front.
Breaching Battery -- a battery constructed
during siege
operations to enfilade a portion of the enemy's defenses or
to batter
down the enemy's walls or parapets.
Breastwork -- a linear earthwork that was
tall enough
to cover the chest of a man standing behind it. A breastwork
could also
be constructed of ad hoc materials, such as logs, stones,
barrels, or
cotton bales. The term is used very generically.
Bulwark -- See Rampart.
Capital -- the imaginary line that bisects an
earthwork's
salient angle.
Casemate -- enclosed and roofed-over
artillery position.
The gun fired through an opening called an embrasure.
Casemates
vaulted with stone were a basic component of permanent masonry
fortifications.
Casemates were constructed only rarely in the field with logs and
earth.
Cavalier -- See Keep.
Cheek -- side of an embrasure, often
reinforced
by gabions or sandbags.
Caponière (Fr.) -- projection from the
front
of a curtain
wall that enabled infantry or artillery to fire into an exterior
ditch.
Cheeks -- sides of an embrasure, often
reinforced
with gabions, sandbags, or logs.
Chemise -- a revetment for an earth
embankment.
Chevaux-de-frises (Fr.) -- portable obstacles
built of
logs with projecting sharpened stakes, joined together by chains;
called
"horses of Friesland" where the device was invented in the
mid-1600s.
Circumvallation -- siege lines built to
"invest," or
enclose, the enemy's defenses. See Countervallation.
Citadel -- See Keep.
Column of Fire -- a volume of fire directed
perpendicular
to the parapet. Entrenched soldiers tended to fire directly to
their
front when under attack, rather than side to side. To deliver
fire where
it was most needed, engineers changed the orientation and
relationships
of a fortification's faces and flanks. Each
segment of
parapet had a specific column of fire that swept the front or
interlocked
with fire from an adjacent segment.
Command -- height of an earthwork above
grade.
Communication Trench -- a ditch and parapet
that connected
one part of an entrenchment with another to move troops and
supplies.
These were sometimes simple shelter trenches, serving as arteries
to direct
reserves to some portion of the line. Called a covered
way if
deep enough to conceal movement.
Continuous Line -- a line of fortifications
presenting
a solid front to the enemy. Parapets, or Curtains, connected all
of the
artillery strong points on the line. See Lines at
Intervals.
Corbeil or Corbeille (Fr.)
-- a form
of gabion; a small wicker hamper wider at the top, placed
in a
row along the parapet and filled with earth. The tapered shape
left a
musketry loop-hole between corbeils.
Corduroy Road -- logs laid side-by-side in a
roadbed
to make it passable in wet weather. The same technique was often
applied
to gun platforms to support artillery pieces.
Counterbattery Fire -- artillery fire
directed at the
enemy's artillery in an attempt to silence or disable the guns.
Because
of the threat of counterbattery fire, artillery positions were
typically
built stronger and more massive than adjacent infantry
entrenchments.
Countermining -- See Mine.
Counterscarp -- outer or exterior slope of a
ditch.
See Scarp.
Countervallation -- siege lines built in
conjunction
with lines of circumvallation to protect the rear of the
besieging
force from assault by a relief force or from raids.
Covered or Covert Way -- in
permanent
fortifications, a walkway extending around the outside of the
moat or
ditch of the main line; in fieldworks, a ditch and parapet
designed to
protect and conceal the movement of troops and supplies to the
front lines
from camps or supply caches in the rear. A covered way was not
"covered,"
in the sense of being roofed over; it provided cover from
gunfire.
Cremaillière (Fr.) or Indented Line --
a
stepped or
saw-toothed line of fortifications, designed to generate
crossing fires
all across the front of the line.
Crest -- See Superior
Slope.
Crossing or Interlocking
Fire -- fire
that converged on the same target from two different points.
When laying
out a line of defense, engineers sought to generate interlocking
fire
whenever possible. See Column of Fire.
Crownwork -- a detached earthwork open at the
gorge,
formed of a central bastion and two flanking
demilunes with
two long flanks extending to the rear and inclining toward
the
gorge.
Cunette (Fr.) -- a narrow drainage ditch
running along the bottom of a trench. Drainage was a continual
concern
whenever an earthwork was occupied for any length of time.
Drainage ditches
have been observed to survive, typically within semi-permanent
forts,
siegeworks, and larger batteries.
Curtain or Curtain Wall -- a
straight
line of parapet that connected two bastions or artillery
strong
points, technically with an exterior ditch.
Dam -- often used in conjunction with
military earthworks to flood an
area for defensive purposes.
Déblai -- the earth removed from an
excavation that provided the bulk of the material used to
construct a rampart or parapet. See Spoil.
Dead Angle -- See Sector without
Fire.
Defilade or Dead Ground -- a
ravine, gully, or depression within range
of an earthwork's weapons that could not be seen or fired into
from the
defenders' position.
Deliberate Entrenchments -- defenses
constructed in anticipation of need,
to defend a town, depot, or bridge, for example, typically
constructed
with a front or exterior ditch. If defending an important
position and
occupied for a long period of time, deliberate earthworks might
be improved
to a semi-permanent condition. Magazines and bombproofs were
built.
The parapets might be sodded with grass, revetments faced with
sawn planks
or stone, roads and ramps paved with flagstones, a well dug, and
a more
complete drainage system installed. Frame barracks and
storehouses might
be constructed within or adjacent to the earthworks for the
garrison.
Deliberate Fieldworks -- improvements made to
an existing line of rapid
entrenchments, typically the addition of detached works
for artillery.
Also siegeworks.
Demi-bastion (Fr.) -- an angular work that
projected outward from the
corner of an enclosed or detached earthwork. A demi-bastion
consisted
of one face and one flank forming a salient angle.
The
flank directed fire across the front of an adjacent face or
curtain.
Demilune (Fr.) -- a crescent shaped parapet
protecting a single cannon,
typically ditched in front. Also called an epaulement; in
permanent fortifications,
a component of the bastion. The term was often used
interchangeably with
lunette, but this is imprecise.
Dentate -- zigzag or saw-toothed parapet
designed to direct fire obliquely
left and right across the front, designed to create interlocking
fields
of fire. See Cremaillière Line.
Detached Works -- fortifications constructed
in advance of the main line
to delay an enemy's approach or built as components of a line
of intervals,
generally redans, ravelins, lunettes, or redoubts. Other
variations included
swallow's tails, hornworks, crownworks, and priest
caps.
Direct Fire -- incoming fire striking
perpendicular to the parapet or
line of battle. Incoming fire could be direct, enfilading,
plunging,
reversed, and ricochet.
Discontinuous Line -- See Line of
Intervals.
Ditch -- excavation providing soil to
construct a parapet. A ditch could
be in front of the parapet (front-ditch or
exterior), behind
it (back-ditch or interior), or on both sides
(double-ditch).
Engineers preferred front-ditch construction whenever time and
labor permitted,
as it created a stronger profile. Batteries, redans,
lunettes,
and redoubts were consistently constructed with a front-ditch.
Back-ditch
construction was the fastest way to entrench, and therefore was
used most
often for rapid infantry entrenchments. A double-ditch resulted
from
digging in front to widen an existing back-ditch parapet, from
constructing
a covered way behind a front-ditched line, or from capture
and
refacing. Some evidence of the ditch-a shallow
trough-often survives
even if its parapet has eroded away. The scarp and
counterscarp
are the inner and outer slopes of the ditch.
Double-ditch -- parapet with both an interior
and exterior ditch. Double-ditching
was used to widen an existing back-ditch parapet or to provide a
covered
way behind a front-ditch parapet. An earthwork that was captured
and
turned (refaced) would have a double ditch. See
Ditch.
Drainage Ditch -- See Cunette.
Dugouts and Bunkers -- rectangular
excavations, usually 5-10 feet on a
side, associated with the principal defenses of an earthworks
complex.
These typically served a command or logistical function. On rare
occasions
in the field or during siege operations, dugouts might be roofed
or partially
roofed with logs and earth.
Earthworks -- any earthen structure excavated
for military purposes.
In simplest form, a defensive earthwork was composed of a parapet
or mound
of earth and a ditch from which the earth was excavated.
Earthworks Complex -- consists of the Main
Line of Defense, a Zone
of Occupation behind the main line, a Zone of Fire in
front
of it, and a Zone of Contention (No Man's Land) separating
advanced
positions of the combatants. The entire fortified front, taking
in both
combatants, might be a mile ore more deep with each zone
identified by
a specific grouping of features and artifacts.
Embrasure (Fr.) -- a wedge-shaped opening cut
to allow artillery to fire
through the parapet. A cannon firing en embrasure had a
restricted (45-degree)
field of fire but the parapet protected the gunners. The sides,
or cheeks,
of an embrasure often were reinforced by logs, planks, stones,
sandbags,
or gabions. Embrasures were common features of artillery
fortifications
and often survive as an indentation in the otherwise uniform
parapet crest.
Not all indentations are embrasures. Typically, there is other
evidence
of the presence of artillery-a gun platform and gun ramp, for
example.
A single gun might have had multiple embrasures. See
Barbette.
Enceinte (Fr.) -- "body of the place," area
of a fort or redoubt enclosed
by the parapet.
Enclosed Work -- an earthwork designed to be
defended from all sides.
See Redoubt.
Enfilade or Enfilading Fire
-- fire from the flank that swept along the
length of a parapet or line of battle. Enfilading fire could be
particularly
destructive as incoming rounds might strike multiple targets and
no return
fire could be brought to bear. Traverses were often constructed
behind
a parapet to limit casualties caused by enfilade. Incoming fire
could
be direct, enfilading, oblique, plunging, reversed, or
ricochet.
Entanglement -- obstacles placed in front of
an earthwork to trip up and
delay attackers, sometimes used to refer to an abattis.
During
the Civil War, telegraph wire was strung from stump to stump at
shin level
to form a "wire entanglement." Most wire was retrieved or
scavenged during
or after the war, so little would be expected to survive
archaeologically.
Entrenchment or Intrenchment
-- generic term for any form of earthen fortification.
In common usage, terms like breastwork, trench, entrenchment
(intrenchment),
curtain, and fieldworks were applied with little precision.
Epaulement (Fr.) -- See Demilune.
Escarp, Escarpment (Fr.), or
Scarp -- rear or inner slope of a ditch.
In a front-ditch earthwork, a continuation below grade of the
exterior
slope of the parapet. See Counterscarp.
Exterior Ditch -- See Front-ditch.
Exterior Slope -- outer side of the parapet
that faced the enemy and intercepted
incoming fire. The exterior slope typically inclined 45 degrees,
the natural
angle of repose for most soils. The interior slope was
more vertical
to enable defenders to stand directly behind it. Nearly all
extant earthworks
in original condition will display some difference in angle
between the
exterior and interior slopes. See Interior and
Superior
Slope.
Face -- a straight segment of parapet making
up a larger earthwork that
delivered direct or oblique fire to the front.
Facing -- covering or treatment of a slope
with sod, sandbags, stone,
or other materials. See Revetment.
Fascine -- tightly bound bundle of saplings
used to reinforce a parapet
or in revetment. Evidence of the use of fascines might appear as
a darker
stratum of soil in an excavated cross-section. See
Revetment.
Field of Fire -- area within weapons range
that can be seen and swept
by fire. Fields of fire were often improved by slashing
(cutting
down) all of the trees or pulling down buildings in front of the
line.
Fieldworks -- earthworks constructed by
armies while actively campaigning,
whether on the battlefield or in camp. Often hasty or
rapid
entrenchments.
Fill -- logs, rails, stones, or other
available materials used to add
bulk to the parapet; typically gathered and placed along the
intended
line before digging begins.
Fire -- organized and directed discharge of
weapons.
Fire Pits or Mess Holes --
See Holes and Pits.
Flank -- left or right end of a line of
battle or position; side; a segment
of parapet thrown back to protect the side of a position or to
allow defenders
to deliver fire across the front of an adjacent face.
Flanking Fire -- fire directed from one
segment of parapet to sweep the
front of an adjacent segment.
Flêche (Fr.) -- a small redan
with a central, bisecting traverse giving it the
appearance of an arrow.
Fort -- an enclosed fortification defended by
artillery; a complex, multi-component
earthwork; a wooden stockade with corner blockhouses, often with
ditching
or other earthen components; generically, a military base.
Fortification -- earthen works or other
structures erected to defend a
place or position.
Fortress -- a system of defenses designed to
work together as a whole
to defend a fixed position. Often a permanent
fortification.
Fossé (Fr.) -- an exterior ditch
fronting a
rampart or curtain.
Foxhole -- an individual shelter hole. See
Holes and Pits.
Fraise (Fr.) -- row of pointed logs set close
together and inclined toward
the enemy, often erected in the exterior ditch of a
redoubt to
prevent attackers from scaling the parapets. Sometimes called a
palisade.
Front -- exterior, toward the enemy.
Fronting -- orientation of an earthwork
vis-à-vis the enemy.
Front-ditch or Exterior
Ditch -- ditch on the outside of a parapet designed
as an additional obstacle to assault. A front-ditch allowed the
parapet
to have greater bulk and a stronger profile than rear-ditch
construction.
This was the engineers' preferred method and was consistently
applied
to prepared fortifications, to detached works, and artillery
fieldworks.
It is common to find a mix of front-, rear-, and double-ditch
entrenchments
in a single continuous line. See Ditch.
Fully Stocked Forest Stand --
This refers to a full overstory canopy capable of replenishing
the forest floor. Foresters typically use basal area to
measure stocking in a forest.
A rule of thumb is that the lower limit of full stocking is
around 60 square feet of basal area per acre. In pine and
pine-hardwood forests, it is 80 square feet per acre. Basal area
(BA) = 0. 005454d 2 BA is basal area in square feet and d = tree
diameter in inches. Summing the basal area from all trees over an
acre provides basal area per acre which is a measure of stocking.
Basal area for mature deciduous forests in the eastern United
States generally range from 100 to 150 square feet per acre.
Gabion -- a large basket of interwoven vines
and saplings used to strengthen
or shape an earthwork. The gabion was set into position, then
filled
with earth on site. When gabions deteriorated, the fill
collapsed into
shapeless mounds that can sometimes be identified in the
field.
Glacis (Fr.) -- outer edge of the ditch, or,
by extension, the field
of fire of a fortification. In permanent fortifications, the
glacis
was shaped so that the ground rose gently as it approached the
ditch to
protect and conceal the masonry revetment of the scarp.
In fieldworks,
time permitting, the glacis was sloped as a continuation of the
angle
of the superior slope of the parapet. Some surviving
artillery
works have a shaped glacis, though it is fairly rare.
Gorge -- entrance to a detached work, or
simply the rear of the work, as in, a lunette is open "at the
gorge." Leaving the rear of a work open allowed defenders in
a secondary line to fire into it in case it were captured. A
wooden stockade was sometimes built to close off the
gorge.
Grade -- original ground level. Ditch
is below grade; parapet
is above grade.
Greater or Major Fieldworks
-- earthworks constructed with an exterior
or front-ditch.
Gun Pit -- an entrenched artillery position,
a platform, demilune
or epaulement.
Gun Platform -- a flat, usually rectangular,
area behind a parapet on
which an artillery piece was positioned. The platform surface
was usually
floored with planks or split logs or corduroyed with logs
placed
side by side. A platform might be excavated or elevated relative
to grade,
depending on whether it was firing through an embrasure or
over
the parapet (en barbette). The size of the platform is
indicative
of the size of cannon it was intended to service (average 10 x 14
ft.
for a standard field piece). Sometimes, a platform was edged by
a narrow
drainage ditch or flanked by traverses.
Gun Ramp -- a ramp constructed to move a
cannon into firing position on
its platform; the ramp may ascend or descend to the platform from
ground
level. A gun ramp is a common surviving feature of artillery
works.
Hasty Entrenchments -- See Rapid
Entrenchments.
Holes and Pits -- foxholes and other
personal defenses. Single-man
skirmish pits or picket holes (foxholes) were typically about
four feet
in diameter and 2-3 feet deep with the dirt thrown forward to
form a low
parapet. These holes were sometimes enlarged to hold two- or
three-man
firing teams. Pickets and skirmishers were deployed from 50-300
yards
in advance of the main line of defense at intervals of 5-15
yards. This
regularity of placement is one of the principal indicators used
in the
field to differentiate a picket or skirmish line from random
holes caused
by tree-throw. Interspersed along the skirmish line might be
slit trenches,
which were short, discontinuous segments of parapet dug to cover
3-5 men.
Fire pits or mess holes might be dug out of the ditch behind the
main
lines for cooking and sleeping. "Officer holes" sometimes appear
at regular
intervals from 5-10 yards behind the main lines, where file
closers, usually
non-commissioned officers, were stationed to keep the rank and
file in
line. See Dugouts and Bunkers.
Hornwork -- detached earthwork formed of two
adjacent demi-bastions
and two long flanks extending to the rear and inclining
toward
the open gorge.
Hurdle -- revetment formed by
interlacing vines or saplings through
a series of posts set upright against the interior slope
of the
parapet.
Impoundment or Inundation --
flooded ground in front of or within a fortification
for defensive purposes.
Improving -- continuing to strengthen a
system of rapid entrenchments
over time. A simple rifle trench could be improved by widening
the parapet,
adding traverses, excavating dug outs or fire pits behind the
line, or
adding supply caches and a covered way to the rear. Soldiers
tended to
work on their entrenchments more or less continuously for as long
as they
occupied them to make them safer, more comfortable, and more
defensible.
Indented Line -- See Cremaillière
Line.
Infantry Works -- earthworks designed for
defense by infantrymen.
Interior Slope -- rear slope of the parapet,
usually nearly vertical to
enable the defender to stand against it to fire over the parapet;
often
faced by a revetment of logs, rails, planks, sod,
wickerwork (called
hurdles), stones, sandbags, or other available materials.
Internal Works -- structures built within a
larger earthwork, such as
magazines, bombproofs, and traverses.
Irregular Works -- See Regular and
Irregular Works.
Keep -- a blockhouse or redoubt built within
a larger fort for use as
a place of final refuge or last-resort defense. Also called a
citadel
or cavalier.
Lesser or Minor Fieldworks -- earthworks
constructed with an interior
or rear-ditch. Because soldiers stood in the ditch to fire over
the parapet,
the total relief rarely exceeded five feet.
Line of Battle -- a tactical, linear
formation of troops in which the
front ranks stood nearly shoulder to shoulder and the rear ranks
stood
behind them in the intervals. Eighteenth- and nineteenth-century
armies
deployed in such dense lines in order to concentrate their
musketry in
a single direction. Since effective fire could be delivered only
to the
front, the entire line of battle needed to shift position to
change the
direction of fire. Military earthworks reflected these linear
tactics.
Lines at Intervals -- a line of mutually
supporting detached works, typically
redans, lunettes, or redoubts that were not
connected
by infantry parapets, also called a discontinuous line. In
theory, lines
at intervals allowed defenders greater mobility to conduct an
active
defense.
Listening Well -- a shaft sunk during siege
operations to detect an enemy's
attempt to tunnel under an entrenched position. See
Mine.
Loop-hole -- a narrow slit through which a
weapon could fire.
Lunette (Fr.) -- a detached earthwork, open
to the rear, composed of two
faces forming a salient angle and two
flanks, flanks
and faces being of nearly equal length. Called a
bastion
when connected to another lunette by a curtain wall.
Imprecisely
applied to a demilune or epaulement.
Magazine -- a secure, water-tight place to
store ordnance supplies; in
prepared works or fieldworks, a log or plank room or bunker
covered over
with a thick layer of earth to protect ammunition from accidental
discharge
or incoming artillery fire. Most artillery fortifications
occupied for
any length of time had at least one magazine, depending on the
number
and types of guns. A surviving magazine typically appears as a
large
mound of earth, sometimes with a depression in the top where
underlying
timbers have collapsed or in the side where the entrance used to
be.
The entrance was to the rear, opposite any incoming fire.
Communication
trenches or at least unobstructed paths for runners lead from the
entrance
to the gun platforms. From visible remains, it is difficult to
tell if
a mound was a magazine or a bombproof. A single mound
within an
artillery fortification is likely to have been a magazine,
because engineers
generally protected ordnance before men.
Maham Tower -- platform of logs, earth, and
gabions constructed
during siege operations to allow besiegers to fire over
the defenders'
parapets.
Main Line of Defense -- line along which the
principal strength and effort
of the defenders was concentrated.
Merlon -- section of parapet between two
embrasures.
Military Crest -- shoulder of a hill or ridge
rather than its actual crest.
The military crest is the highest contour of elevation from which
the
base of its slope can be seen without defilade. When
surveying
an area for surviving earthworks, it is often useful to search
along the
military crest.
Mine -- tunnel dug beneath an enemy
fortification, either to undermine
its foundations or to set off an explosion. Mine tunnels are
occasionally
discovered today in association with siegeworks, usually when a
portion
of it collapses. The best defense against enemy mining was
counter-mining,
digging tunnels to intercept the enemy's mine.
Moat -- ditch in front of an earthwork that
was purposely filled with
water.
Mutual Support -- two artillery or infantry
strong points, each within
the other's range and field of fire and able to assist the
other
if attacked. Engineers typically designed a fortification so
that its
parts were mutually supporting.
No Man's Land -- See Zone of
Contention.
Oblique Fire -- incoming fire that strikes
the parapet or line of battle
at an acute angle from left or right. Incoming fire could be
direct,
enfilading, oblique, plunging, reversed, or
ricochet.
Palisade (Fr.) -- a phalanx of sharpened logs
or fraise, anchored
in a shallow ditch and slanted to the front as an obstacle to
advancing
infantry. Also a wall of logs or stockade.
Pan Coupé (Fr.) -- a short straight
stretch
of parapet constructed across
the capital of a salient angle, having the effect of reducing the
angle's
sector without fire.
Parade or Parade Ground --
flat assembly area within a larger permanent
or semi-permanent fortification; often adjacent to barracks or
other garrison
buildings; sometimes improved by leveling and draining.
Parallel -- a parapet thrown up to confront
defenses when conducting a
siege by regular approaches. The First Parallel
was constructed
out of range of the enemy's guns. Saps were pushed
forward fifty
or a hundred yards to construct a Second Parallel, and so on,
until reaching
the ditch of the enemy fortification. Imprecisely applied to
describe
a curtain wall.
Parallel Fire -- fire directed across the
front of an entrenched line
or line of battle.
Parapet (It. parapetto, shield the
chest) --
a linear mound of earth
built to defend against incoming fire. The thickness of a
parapet was
determined by the armament that it was expected to withstand-for
musketry,
5-7 feet; field artillery, 8-16 feet; for siege or naval guns, up
to 35
feet. The parapet consisted of an interior slope, usually
revetted
with logs, planks, rails, stones, sandbags, or fascines, so as to
be nearly
vertical, the superior slope or crest, which
inclined slightly
downward toward the enemy, and the exterior slope or outer
face,
which took the brunt of enemy fire. The exterior slope typically
inclined
45 degrees, the natural angle of repose for most soils.
Passive Defense -- strategy of holding an
entrenched position and awaiting
the enemy's attack.
Peneplein (Fr.) -- flat interior of an
enclosed earthwork, synonymous
in usage with terreplein.
Permanent Fortifications -- defenses
constructed to defend towns, garrisons,
depots or other fixed positions that were intended to last for a
long
time with minimal repair. A fort's ramparts could be constructed
entirely
of stone and brick or, if built largely of earth, would have
masonry revetments
within and without to deter erosion.
Picket -- a guard or vidette.
Picket Holes or Skirmish
Pits -- See Holes and Pits.
Picket Line -- a row of guards, or videttes,
spread out in intervals and
formed in advance of the main line to provide warning of an
attack; a
row of individual foxholes entrenched by the pickets. Picket
lines were
advanced anywhere from 50-300 yards in front of the main lines,
depending
on the terrain and proximity of the enemy.
Platform -- See Gun Platform.
Plunging Fire -- fire directed from higher to
lower ground.
Postern -- See Sally Port.
Prepared or Provisional
Entrenchments -- See Deliberate Entrenchments.
Priest Cap -- a detached earthwork consisting
of two faces joined
in a reentrant and two long flanks extending toward
the
rear and inclining away from the open gorge. The design served
to converge
the fire of the two faces on a specific target to the front. The
severity
of the re-entering angle determined the distance to the point of
convergence.
Profile -- cross-section of an earthwork.
The higher and wider the parapet,
the wider and deeper the ditch, the "stronger" the profile. A
simple
rear-ditched rifle trench had a "weak" profile.
Ramp -- an incline leading up to the
banquette
or allowing access to a gun platform.
Rampart -- a broad embankment of earth that
supported
the functioning elements of a permanent or semi-permanent
fortification.
The parapet and banquette were built at the front of the rampart;
ramps
moved troops from the interior of the work onto the
terreplein
of the rampart. In early forts, a rampart was often improvised
by constructing
double parallel revetments of logs and filling the intervening
space with
stones and hard-packed earth. Ramparts typically were not a
component
of field fortifications but appeared occasionally in simpler form
in some
artillery works. Sometimes called a bulwark.
Rapid Entrenchments -- fieldworks constructed
in the
presence of the enemy, usually with a rear or interior ditch and
often
with ad hoc materials for fill and revetment, also called hasty
or temporary
entrenchments. Although built "hastily, " these were rarely
built "carelessly,"
as the modern use of the word might imply. Experienced soldiers
could
throw up a shelter trench sufficient to absorb small arms fire in
less
than an hour with only rudimentary tools.
Ravelin -- a detached earthwork open to the
rear with
two long faces forming a salient angle and two
short flanks.
See Detached Works.
Rear -- interior, away from the enemy.
Rear-ditch or Interior Ditch
-- ditch
in which soldiers stood to fire over the parapet; most commonly
used in
rapid infantry entrenchments. Rear-ditch was the fastest way to
entrench
because each shovel of earth lowered the ditch and at the same
time raised
the parapet. See Ditch.
Redan (Fr.) -- a detached fortification with
two faces
forming a salient angle, often built as an outer work to
cover
an advanced position. The work was open at the rear. A redan
was a common
form of all military eras. When bisected by a traverse down its
center
(along the capital line), it was called a flêche, or
"arrow."
When connected to adjacent strong points by curtain walls, it
served as
a caponière.
Redan Line -- a series of redans
connected by
curtains.
Redoubt -- an enclosed fortification designed
to be defended
from all sides. The trace of a redoubt could be square,
polygonal,
or occasionally circular. A redoubt could stand alone as a
detached
work, serve as a place of refuge within a larger
fortification, or
be incorporated into a continuous line of entrenchments as an
artillery
or infantry strong point. Redoubts were a common feature
of all
military eras.
Reentering Angle or Reentrant -- angle in an
earthwork
or line of earthworks that points toward the rear and away from
the enemy.
Systems of earthworks were purposely designed with both
reentering and
salient angles.
Reface -- to "turn" or change the
facing of an
earthwork.
Relief -- distance from the crest of the
parapet to the
bottom of the ditch; relief is a component of the
profile.
Regular Approaches -- siege operations
conducted by building
saps, parallels, and breaching batteries, based largely on a
system devised
for the French armies by Sebastien le Prestre de Vauban
(1633-1707).
Regular and Irregular Works -- enclosed
earthworks.
Regular works were based on classic models-square or six-sided
redoubts,
and bastioned forts-and generally appeared balanced in proportion
and
symmetrical in trace. Irregular works were adapted to the
peculiarities
of the terrain and took a variety of shapes and traces. Although
less
"elegant" in terms of geometry, irregular works were often
measurably
stronger than the more rigid, classical prototypes.
Remblai -- the material used to construct a
rampart or parapet, the bulk of this material provided from earth
removed by excavation. See Spoil.
Retrenchment -- a secondary line of
earthworks built
to seal off a gap in the main line or to prevent a
breakthrough.
Reversed Fire -- incoming fire that strikes
the rear
of a parapet or line of battle. Incoming fire could be direct,
enfilading,
oblique, plunging, reversed, and ricochet.
Revetment -- retaining wall constructed to
support the
interior slope of a parapet. Made of logs, wood planks, fence
rails,
fascines, gabions, hurdles, sods, or stones, the revetment
provided additional
protection from enemy fire, and, most importantly, kept the
interior slope
nearly vertical. Stone revetments commonly survive. A few log
revetments
have been preserved due to high resin pine or cypress and porous
sandy
soils. After an entrenchment was abandoned, many log or rail
revetments
were scavenged for other uses, causing the interior slope to
slump more
quickly. An interior slope will appear more vertical if the
parapet eroded
with the revetment still in place.
Ricochet Fire -- fire that strikes the ground
first then
bounds into the air, used primarily by artillery firing a round,
solid
shot. The glacis was shaped to deflect ricochet rounds up
and
over the parapet rather than into it.
Rifle Pits -- generically, any grouping of
light, rapid
entrenchments, usually discontinuous, with a rear-ditch and low
parapet.
See Holes and Pits.
Rifle Trench -- a parapet for infantry,
typically thrown
up rapidly with a rear-ditch. Also called a shelter trench.
Salient -- a portion of a system of
earthworks that protruded
or bulged outward toward the enemy.
Salient Angle -- an angle in a work or line
of earthworks
that pointed toward the enemy. See Reentering Angle.
Systems
of earthworks were designed purposely with both reentering and
salient
angles.
Sally Port -- opening left in the parapet as
an entrance
to an enclosed earthwork. All enclosed earthworks had a sally
port; called
a postern when vaulted or roofed to form a tunnel.
Sandbags -- used to strengthen prepared
entrenchments
and siegeworks, often filled off-site and transported to the work
under
construction. A stratum of sand overlying a different base soil,
particularly
in an artillery work, might indicate the use of sandbags.
Sap -- a trench built to connect one parallel
to the
next in order to advance siegeworks, sometimes built as a zigzag
approach
or straight with internal traverses. See Regular
Approaches.
Sap Roller -- a large wickerwork cylinder
rolled ahead
of a crew to absorb incoming fire as it worked on a
sap.
Sapper -- a pioneer or engineer engaged in
digging field
or siegeworks.
Scarp, Escarp, or Escarpment -- inner slope
of the ditch,
as opposed to counterscarp, the outer slope of a ditch.
Both scarp
and counterscarp are below grade and are visible components of
all ditches.
Sector Without Fire -- area in front of a
salient
angle into which the defenders cannot fire. A sector without
fire
was extremely vulnerable unless defended by fire directed from
another
part of the fortification.
Shelter Trench -- a simple rifle trench for
infantry,
typically with a rear-ditch.
Siege Operations -- systematic entrenching to
approach
an enemy's defenses, using classic engineering techniques. See
Regular
Approaches.
Siegeworks -- earthworks built to advance or
retard siege
operations.
Skirmish Line -- soldiers deployed at
intervals in front
of the main line of battle to harass the enemy and delay any
enemy advance;
a row of individual foxholes entrenched by the skirmishers.
Skirmish
lines were advanced anywhere from 50-300 yards in front of the
main lines,
depending on the terrain and proximity of the enemy.
Sharpshooters often
manned the skirmish line.
Skirmish Pits or Picket
Holes -- See
Holes and Pits.
Slashing -- cutting down all trees in front
of a line
to create a clear field of fire. Trees were felled in the same
direction
with branches toward the enemy, serving as an obstacle to
attack. Downed
trees might then be trimmed and arranged more formally into an
abattis.
Slit Trench -- slang for a short trench,
similar to a
rifle pit, constructed for 3-5 men. Often found in a picket line
interspersed
with foxholes or as shelter in the rear of a main line.
Spoil -- earth removed from an excavation,
termed in French the déblai. The spoil provided the
bulk of the remblai, that is, the material used to
construct a rampart or parapet.
Star Fort -- an enclosed work with
alternating salient
and reentering angles. A star fort might have from
four
to eight salient angles projecting toward the enemy. This was a
popular
form until the middle of the Civil War, but many engineers
considered
it to require more work than needed for a strong defense.
Examples of
star forts survive from various time periods.
Stockade -- generically, a log fort; when
used as an
adjunct to earthworks, a vertical wall of logs tied or nailed
together
to protect the flank or gorge of a battery,
lunette, or
redoubt. Loopholes were cut in the logs to allow for rifle
fire. The
exterior of the stockade wall might be ditched with the earth
thrown up
against the logs. Archeological excavation might reveal evidence
of the
postholes or remains of the post in the ground.
Strong Point -- a dominating position,
usually high ground,
defended by entrenched artillery or a concentration of
infantrymen; an
artillery work within a continuous line of entrenchments.
Superior Slope -- crest of the parapet on
which soldiers
rested their
weapons to fire. The interior slope was nearly
vertical
so that a man could stand comfortably against it. The superior
slope
inclined slightly toward the enemy. The exterior slope,
which
intercepted most incoming fire, inclined more abruptly. See
Parapet.
Supply Cache -- a rectangular excavation,
usually 5-10
feet on a side and three feet deep, found in rear of the Main
Line of
Defense. See Earthworks Complex. These served as
temporary storage
for boxes of food or ammunition and are found in sheltered
terrain adjacent
to a road or a covered way. On rare occasions in the field or
during
siege operations, a supply cached might be roofed or partially
roofed
with logs and earth.
Swallow's Tail -- a detached earthwork
consisting of
two faces joined in a reentrant and two long flanks
extending
toward the rear and inclining toward the open gorge.
Tenaille (Fr.) Line -- a series of adjacent
redans,
of equal or differing sizes, joined at the flanks with no
connecting curtains.
Terreplein (Fr.) -- ground level, grade;
generically
a level area inside an enclosed fortification; in permanent
fortifications,
the flat surface of the rampart behind the parapet.
Tête-de-pont (Fr.) -- an entrenched
bridgehead with both flanks anchored on a river, designed to hold
a river crossing.
Throw Up Works -- to entrench. Earthworks
were described
as being "thrown up."
Trace -- outline of a fortification as drawn
on a plan
or "traced" upon the ground. In terms of engineering, the trace
of an
earthwork was its most important characteristic. To be
effective, the
trace should take advantage of the military strengths of the
terrain and
mitigate its weaknesses; its design should accomplish its purpose
in the
overall plan of defense; its length should be adjusted to the
number of
soldiers designated to hold the position.
Traverse -- a short segment of parapet used
to prevent
incoming enfilade fire from sweeping the length of a line,
to protect
the rear wall of an enclosed work from a plunging fire
from the
front, to cover a sally port, or to provide extra protection for
a magazine
or supply cache. Traverses were sometimes built of or reinforced
by gabions
and were usually constructed perpendicular to incoming fire,
rather than
perpendicular to the defensive parapet. In rapid entrenchments,
traverses
might be constructed entirely of logs.
Trench -- usually short for entrenchment,
sometimes referring
to the ditch of an entrenchment or to an auxiliary entrenchment
in rear
of a rampart.
Trous de loup (Fr.) -- rows of pitfalls, 4-6
feet deep,
dug in checkerboard fashion in front of an earthwork to obstruct
to an
attacking force. Each cone-shaped pitfall concealed a sharpened
stake.
Turned Works -- an entrenchment captured by
the enemy
and refaced, resulting in ditching on both sides of the
parapet.
Work -- any discrete component of a system of
fortifications,
applied most often to detached defenses, to forts, or artillery
strong
points.
Zigzag Trench -- See Boyau.
Zone of Contention -- No Man's Land, the area
separating
the deployed skirmishers of the combatants, often defined by the
foxholes
of the opposing skirmish lines. Because skirmishers tended to
advance
or withdraw according to nuances of the terrain and localized
pressure,
the width of this zone fluctuated. See Earthworks
Complex.
Zone of Fire or Kill Zone --
area between
the Main Line of Defense and the advanced skirmish or
picket line,
typically no wider than the effective ranges of standard infantry
weapons.
In this zone, soldiers cut down trees to clear a field of fire
and often
erected obstacles, such as an abattis or entanglements, to
slow
down and break up an attack. Nothing would remain from such
obstructions
unless it was the shallow ditch that anchored the abattis. One
might
find larger dugouts that held reserve pickets that could be fed
out to
the skirmish line as needed. See Earthworks Complex.
Zone of Occupation -- area behind the Main
Line of Defense.
This zone might extend 200 yards or more behind the front,
depending on
the terrain. In this zone were activities of logistics and
support,
which sometimes left evidence in the form of support trenches,
dug-out
supply caches, bunkers for officers and non-combatants, or
covered ways
through which troops and supplies could move unseen from the rear
to the
front line. In some cases, artillery positions were constructed
to fire
over the front lines at distant targets. See Earthworks
Complex.