As detached works to this line, it was intended to hold those on New Market Heights and Camp Holly, which would have given us the command of New Market, Kingsland, and Darbytown roads. The necessity for this line never occurring, it was never occupied by troops.

After the occupation of Fort Harrison and the rebel captured lines, the enemy began the construction of a new line of defense joining their water batteries on the river at Chaffin's farm with Fort Gilmer, and running thence easterly to join on to that portion of the captured line which we could not occupy at the Charles City road, and so on to New Bridge on the Chickahominy.

The line that our forces occupied was made as strong as possible, and possessed the advantage of having but a short part exposed to an attack of the enemy, which part was strongly manned and guarded.

On the 27th a movement was made on the Darbytown and Williamsburg roads with no other result than to keep the enemy form sending re-enforcements to the right of their army at Petersburg, which was then being attacked by the Army of the Potomac. During this movement General Weitzel's troops fought on the same ground in advance of Seven Pines on which the Army of the Potomac fought in 1862.

November.-Details of both engineers and infantry were constantly employed during this month in repairing the works of defense and perfecting and completing those alluded to. During this season the roads used by the supply trains from the wharves and bridges became much cut up, and corduroying was commenced. Wharves for the quartermaster, ordnance, commissary, and medical departments were built at suitable places on the river. Frequent rumors arriving at Fort Harrison that the enemy were mining the work, in order to allay the fears of the garrison well holes were dug on the glaces to serve for listening galleries. As the nearest approach of the rebel works was 800 yards and a valley twenty feet deep had to be crossed before reaching the work, but little attention was paid to these rumors.

While attention was paid to the defensive operations we also found time to collect, repair, and put in working order three saw-mills, which were located in a splendid forest in the Bermuda woods. By these mills from 7,000 to 10,000 feet of lumber were sawed per day, the greater portion of which was used in the construction of a permanent hospital at Point of Rocks. Sufficient was obtained, however, to stock the engineer depot and built platforms and magazines in all the batteries, wharves, and bridges on the river.

Below is a report of the engineer force of the army, and how employed, which may be taken as a fair standard of each day's detail during the period of quiet:

Two officers, 80 men, building redoubts and corduroying roads; 2 officers, 66 men, repairing Tenth Army Corps front; 2 officers, 90 men, repairing Eighteenth Army Corps front; 1 officer, 30 men, bomb-proof to dredge Dutch Gap and Fort Brady; 1 officer, 50 men, corduroying roads; 2 officers, 30 men, engineer depots at Bermuda and Fortress Monroe; 2 officers, 143 men, various small details, $c.-12 officers, 489 men. First New York Volunteer Engineers-four officers, 105 men, on duty at saw-mills, building wharf, pontoon bridges, repairing wagons, &c.

December.-This month's labor was a continuation of the last, and the principal roads of supply were ready for winter use quite early in the month. Whatever damages had been done to the defenses were