Adam Badeau, Military history of Ulysses S. Grant from April 1861 to April 1865. Volume 2

[3] defended by a triple line of fortifications. First of all, at an average distance of a mile and a half from the centre of the city, a series of detached fieldworks was constructed, so placed as to command the principal avenues of approach. These works were twelve in number, five of them complete redoubts, and all arranged for either siege or field artillery, while some were provided with magazines. They had been built by slave labor in the first year of the war, every proprietor in the neighborhood having been compelled to furnish from one-sixth to one-third of his entire slave force for their erection.

Exterior to these was a continuous line completely encircling the town, at a distance of three miles. It consisted of epaulements, arranged generally for field artillery, sometimes in embrasure, sometimes in barbette, and connected by rifletrench. These works were not extended to the southern bank until after Butler's attack on Drury's Bluff in May, 1864, when the rebels, fearing another advance from the same direction, completed the line. It was never attacked except by reconnoitring forces in 1864 and 1865.

The third line, starting from the river above the town, and crossing the country at a general distance of six miles from Richmond, reached to the bluffs overlooking the valley of the Chickahominy, the crests of which it followed for a while, and then took an easterly course, striking the James again, at the strong entrenched position on Chapin's Farm, opposite Drury's Bluff. This was the line occupied by the rebel armies during the last year of the war, and attained a high stage of development. It consisted of a series of strong forts, with ditches and