The Photographic History of The Civil War: in ten volumes, Thousands of Scenes Photographed 1861-65, with Text by many Special Authorities, Volume 1: The Opening Battles.
Francis Trevelyan Miller, Ed.

Formidable fieldworks: new necessities of warfare.

The increased deadliness of firearms taught the commanders in the Civil War the habit of greatly strengthening every new position occupied with earthworks as formidable as possible. The works in the first picture were thrown up in a night by the Federals near North Anna River, Virginia, in 1864. It is apparent how they would strengthen the resistance of a small force to larger numbers who might advance across the open upon the position. In the second picture we see the salient of “Fort Hell,” with its ditch and abattis and breastworks constructed of gabions, the result of many days' work of the soldiers in anticipation of attack. This was one of the fortifications about Petersburg, where the construction of fieldworks was developed to the highest point of efficiency.

Formidable fieldworks in an advance: works thrown up in a night by the Federals near North Anna River, Virginia, in 186

Salient of “Fort Hell”