Masonry adjuncts, advantageous to all retaining walls, but especially to those which, like the escarps of fortresses, are liable to be battered. They are attached at regular intervals to the hinder face of the wall, and perpendicular to it; having various proportions, but generally the same height as the wall; they hold it from being thrust forward from behind, and, even when it is battered away, retain the earth at the back at such a steep slope that the formation of a practicable breach remains very difficult. When arches are turned between the counterforts, the strength of the whole structure is much increased: it is then called a counter-arched revêtement.