Earthworks

Defensive positions were formerly protected by means of permanent works having masonry scarps and counterscarps, requiring regular siege operations to reduce them. Positions of temporary military importance may be made more secure by fortifications constructed entirely of earthen parapets with revetments also temporary, as gabions, fascines, and hurdles. The principal cla es are lines with intervals, continuous lines. redoubts, redans, and bridgeheads. The profile of these works consists usually of the exterior slope, generally the natural slope of earth; the superior slope, or that of the most depre ed line of fire required for exterior defense; the interior slope, or that inclination best suited for delivering musketry fire; the banquette, and the banquette slope which unites the tread with the interior surface of the work. Other earthworks for the protection of field and siege batteries receive such a thickne of para parapet as will secure them from through penetration by the art iller artillery projectiles of the enemy. Shallow trenches for the rapid covering of infantry when brought into action upon ground that is to be held for a short time belong also to earthen fortification. Earthworm. See TERRICOLÆ.