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Assessment of the Principal Earthworks:

The Federal "Fish Hook" Line, Petersburg, VA


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Abatis or Abattis (ah-bah-tee'): a barricade constructed of small trees, felled, and aligned with branches pointing toward the enemy. Trunks were often secured in a shallow trench, the branches sharpened and interlaced to present a formidable hedge to an attacking force.
Angle: where two faces of a work meet

Apex: foremost angle of a work

Balk: a narrow barrier of earth within the ditch of an earthwork that was purposely left undug.

Barbette or en barbette (ahn bar-bet'): placing an artillery piece so that it fires over the top of a parapet as opposed to through a slit in the parapet called an embrasure. Barbette fire allowed the gun more flexibility, up to a 90-degree field of fire, but provided less protection for gunners than embrasures.

Bastion: an earthwork configuration with two faces and two flanks, forming three salient angles; typically connected to another bastion by a parapet or curtain wall.

Bastioned fort: an enclosed earthwork with bastions in the angles to provide fire along the fronts of the connecting curtain walls.

Battery: 1) an Artillery unit
2) earthwork designed to defend an Artillery unit

Baulk: A strip of ground left un-dug in the trench, to serve as a divider or for protection

Caponière: redan that protrudes from the front of a curtain wall to enable infantry or artillery to provide enfilade fire into the ditch

Casemate: an enclosed and roofed over gun position

Counterscarp: the outer slope of the ditch

Covered Way: an entrenchment in which the ditch serves as a road or pathway while the parapet protects from incoming fire. This allows access to a position from the rear without exposure to fire.

Curtain Wall: a parapet connecting bastions or batteries in a line of entrenchments

Dead ground: a depression within an earthwork's field of fire that cannot be seen

Débouchés: Outlets for moving troops

Detached Work: a work to the front of the main line of fortifications

Ditch: excavation associated with the parapet, can be in front or rear of parapet, often called a moat when in front of the parapet

Dentate: zigzag or toothed appearance

Ditch: excavation from which earth or "spoil" is removed to form a parapet. If filled with water, the ditch might be referred to as a moat. All entrenchments consist of a ditch and parapet. The parapet is a mound built up from the excavated earth.

Ditch-in-front, ditch-in-rear, ditch both sides: three forms of parapet construction. Ditch-in-front places both the ditch and parapet between the enemy and the earthwork's defenders. Excavated Earth is thrown towards the rear against a revetment constructed of logs, wicker, stones, sod, or other materials to form a parapet. Ditch-in-front is the strongest form of entrenchment and was favored by engineers when time allowed. Ditch-in-rear is the fastest form of entrenchment. Spoil is thrown to the front, often upon a fill of logs, stones, or other materials, to create a parapet. Because the defender stands in the ditch with the parapet covering his body, only half as much earth needs to be excavated. Ditch-both-sides was used to widen a parapet as defense against artillery fire, to create a covered way behind the parapet, or simply to provide enough protection in areas where there was shallow topsoil.

Earthworks, earthwork: an earthen structure built for military purposes

Embrasure or en embrasure: 1) placing an artillery piece to fire through a slit made in the parapet. 2) break or depression allowing artillery to fire through the parapet. Embrasure fire provided more protection for gunners but restricted a gun's field of fire to about 45 degrees.

En Barbette: artillery positioned to fire over a parapet rather than through an embrasure in the parapet

Enceinte (en-saint'): area of a fort or redoubt enclosed by the parapet

Enfilade Fire: fire to or from the side or flank of a position

Entrenchment: any type of earthen fortification

Epaulement: semi-circular parapet protecting a single cannon, typically ditched in front

Face: a straight section of parapet making up a larger earthwork that delivers direct or oblique fire to the front

Fascine (fa'-sheen): saplings tied into long bundles often used in earthworks construction

Field of Fire: area in front of an earthwork that can be covered by weapons

Flank: 1) the right or left of a formation; the side (e.g. left flank, right flank)
2) a straight section of parapet making up a larger earthwork that delivers enfilading fire

Fort: generically applied to all enclosed earthworks; technically an earthwork with bastions

Fraise (frez): a row of pointed logs placed close together and inclined toward the enemy

Front: toward the enemy

Gabion: a wicker basket filled with earth often used in earthwork construction

Glacis (glah-see'): the area adjacent to the outer perimeter of the ditch, often graded to deflect incoming rounds up and over the parapet of the earthwork.

Gorge: the rear of an unclosed earthwork; a palisade was often constructed across the gorge to protect the rear

Grade: original ground level; ditch is below grade, parapet above grade

Gun Pit: parapet thrown up to protect a cannon, often enclosed by traverses

Gun Platform: a leveled area, typically rectangular and surfaced with planks or logs to support the weight of a cannon

Gun ramp: a ramp constructed to move an artillery piece onto its gun platform

Keep: redoubt behind a main line which can be used for a last-resort defense, sometimes called a citadel

Line of Works: system of fortifications

Lunette: work with four faces and three salient angles, ditched in front and open in the rear, called a bastion when connected to other redans or lunettes by a curtain wall

Magazine: a watertight planked room covered over with earth, built to store ordnance

Military Crest: contour of slope from which the bottom of the valley or ravine can be seen

Moat: ditch in front of a parapet

Ordnance: military supplies including weapons, ammunition, combat vehicles, and maintenance tools and equipment

Palisade: a stockade

Parapet: mound of earth thrown up as a protective barricade, made up of spoil removed from the ditch; often called a breastwork

Picket Hole: fox hole

Priest Cap: type of work shaped like a letter M, two adjacent redans

Profile: the cross section of an earthwork

Rampart: an earthen platform constructed to raise the height of a gun platform or a surmounting parapet; rarely seen in late war earthworks.

Rear: away from the enemy

Redan: an earthwork having two faces that form an angle pointing toward the enemy

Redoubt: an enclosed earthwork, typically without reentering angles

Reentrant Angle or reentrant:: an angle in an earthwork that points away from the enemy

Refused: turned back at a sharp angle to cover the flank

Relief: height from bottom of the ditch to the top of the parapet

Revetment: a framework supporting the interior slope of the parapet, constructed from logs, fence rails, wicker work, sand bags, gabions, sod, stone, or other materials.

Rifle Trench: simple parapet with ditch in rear

Rifle Pit: fox hole, shelter hole

Salient: longer section of line that protrudes to the front, often held by a specific unit

Salient Angle: an angle in an earthwork that protrudes toward the enemy

Sally Port: opening left in a parapet left as an entrance into an enclosed earthwork

Sap Trench: trench dug by the besieger to get close to the enemy's line

Scarp: inner slope of the ditch

Slit Trench: short trench for 4-5 men often found in association with rifle pits

Spoil: earth removed from the ditch

Stockade: a line of stout posts set firmly to form a defense; an enclosure or pen made with posts and stakes; an enclosure in which prisoners are kept

Sump: a hole to collect run-off

Trace: the basic outline of an earthwork

Traverse: a segment of parapet built to protect from enfilading fire

Trench: earthwork formed by digging a ditch and piling earth into a parapet

Wire entanglement: telegraph wire strung from post to post at shin height to impede the progress of an attacker


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