HDQRS. ARMY OF THE POTOMAC, ENGINEER DEPT.,
November 7, 1864.

COLONEL: The following report for the week ending on the 5th instant, exhibiting the engineering operations of the Army of the Potomac, during that period, is respectfully submitted for the information of the lieutenant-general commanding the Armies of the United States:

Captain Harwood, in command of the battalion of the U. S. Engineers, was ordered early in the week to make an examination of the line between the Weldon railroad and the Appomattox River, and report upon the progress of the alterations and additions previously determined upon. The nature of these improvements will appear in the extracts made from Lieutenant-Colonel Spaulding's report, this officer having been directed to furnish the engineer troops to execute them. Lieutenant Benyaurd, assisted by Lieutenant Lydecker, superintended the construction of the redoubts near the Avery house and the Friend house, and the former also directed the countermining at Fort Stedman. The redoubts have both been completed and the listening galleries driven forty feet. Lieutenant Howell has had charge of the construction of Fort Conahey. The parapet and stockade are finished and the interior works are being pushed rapidly forward. Lieutenants Phillips and Heap have been engaged upon the construction of new magazines in Fort Howard and Battery 26.

The following extracts are made from Colonel Spaulding's weekly report, setting forth the operations he was directed to take charge of, and the condition of the works constructed by the troops of his command:

During the week Lieutenant Taylor, with one company of this regiment, has been engaged in cutting and hauling material and building fraise around Battery Numbers 5, countermining at Fort McGilvery, and fitting the redoubts at the Jordan and Avery houses for temporary use. Three hundred and fifty feet of fraise has been built and thirty-one feet of gallery mined. The material is so loose in this gallery that it is necessary to support it for the whole distance, and but few inches can be cut at a time without supporting the roof. The earth has to be shoveled about 400 feet from the entrance to the mine, and consequently on Thursday, I sent wheelbarrows from the entrance to the mine, and consequently, on Thursday, I sent wheelbarrows from Fort Stevenson to Fort McGilvery. The extent of the countermining that may be required at this point is yet uncertain.

On the afternoon of Tuesday, the 1st instant, I sent Captain Hine with five companies of this command to complete the redoubts at the Jordan and Avery houses, and to strengthen the rear line of the forts from Fort McGilvery to Fort Sedgwick. Ramps and platforms have been built in the rear faces of these forts for barbette guns as follows: Four in Fort Stedman, two in Fort Haskell, three in Fort Morton, two in Fort Rice, one in Fort Meikel, three in Fort Sedgwick. Battery 10 has been rivetted. The redoubt at the Jordan house was completed last evening. The redoubt at the Avery house is in fighting condition and will be completed to-morrow. I directed Captain McGrath (Captain Hine having obtained leave of absence) to putt three companies of this regiment at work upon this unfinished redoubt this morning and dispense with infantry details. On Monday afternoon I sent Captain Van Brocklin with his company to resume work on Fort Stevenson. The detail furnished during the week for this work has been small and not very efficient. The rainy weather has also caused some delay in the progress of the work. The fort is now ready for seven barbette and eighteen embrasure guns; also 650 feet of infantry baguette ready for use. This work has so far progressed that not more than 200 men at a time can be employed to advantage, and Captain Van Brocklin estimates that with this detail the work, including the abatis, may be completed in five days.

In the topographical department a map of the country west of the Weldon railroad is being prepared to correspond to the one extending north to the Appomattox River-scale, eight inches to one mile. One has also been prepared (scale, two inches to the mile) of the field of operations of this army during the late movement. Copies are being made of the additional section of the map captured from the enemy. The Richmond sheet of the series of campaign maps has been finished