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

Ames now brought up Bell's brigade, and moved it between the work and the river. On this side there was no regular parapet, but the rebels found abundance of cover in the cavities from which sand had been taken for the construction of the fort, the ruins of barracks and storehouses, and the large magazines, behind which they stubbornly resisted the national advance.

It was not until the work was absolutely entered that its formidable character became fully apparent. The heaviest fortifications extended from the gateway which Curtis had forced to the ocean beach, and thence along the sea front a mile away. Twenty-one guns and three mortars had been mounted on the land face, twenty feet above the ditch. The stockade outside was twenty feet high, and the guns were placed to play over it. Between each pair of guns and its neighbor, or sometimes between two guns, a traverse crossed the embankment, rising twenty feet higher. The distance from the glacis to the top of the traverse was thus forty feet. These traverses were made of sand, twelve feet thick at the top, entirely filling the spaces between the guns, and extending nearly across the parapet. There were seventeen of them between the sally-port and the bastion at the north-east corner. Each traverse covered a bomb-proof, and was a fort in itself. From the north-east bastion an enfilading fire could be obtained in either direction, and the guns along the parapet could be trained to work against the interior of the fort as well as outwards.

And now began such a system of fighting as has seldom been equalled in modern battle. The rebels had fallen back, but it was only to rally. Fort Fisher