Numbers 6. One map of Dutch Gap, showing survey of ground with contour lines.

Numbers 7. One map of Dutch Gap and entrenchments.

Numbers 8. One section of signal tower, with bill of lumber and material.

Very respectfully, your obedient servant,

PETER S. MICHIE,

First Lieutenant, U. S. Engineers,

Acting Chief Engineer, Dept. of Virginia and North Carolina.

Bvt. Major General J. G. BARNARD,

Chief Engineer, Armies in the Field, City Point, Va.

HDQRS. DEPT OF VIRGINIA AND NORTH CAROLINA,
CHIEF ENGINEER'S OFFICE,

September 18, 1864.

GENERAL: I have the honor to submit the following report of engineering operations of this department for the week ending September 17:

The excavation at Dutch Gap has progressed very well for the small number of men at work there during the week. The labor is a little more than half finished-a rough estimate. The enemy's mortar batteries have been very active of late, and having moved to within 300 yards of the gap, have been more troublesome than ever. As far as cam be learned, there are four Coehorn mortars in position. The casualties on our side have been very few, considering the number of men and animals engaged. A part of my force has been engaged in repairing and putting in running order a saw-mill found in the woods. It will be ready for use in two weeks. A force of 200 infantry and fifteen engineers has been at work on the line of defenses on our front. A new line has been laid out, joining Numbers 3 and Numbers 5 batteries, as shown by the accompanying tracing.* By this arrangement Battery Numbers 4 will be isolated from the line of works and form a part of the advanced line of works. This shortens the infantry line of defense about 100 yards and is better adapted to the movement of the troops behind the lines. The work at Harrison's Landing has progressed well. The main work, or redoubt, is now completed, its gorge closed with stockade, and the whole surrounded with abatis. From the right and left flanks an infantry parapet, four feet six inches high, runs half way to the river shore. The remainder will be completed within eight days, when a full description and plan of the works will be submitted.

I have the honor to be, general, very respectfully, your obedient servant,

PETER S. MICHIE,

First Lieutenant, U. S. Engineers,

Acting Chief Engineer, Dept. of Virginia and North Carolina.

Byt. Major General J. G. BARNAR,

Chief Engineer, Armies in the Field.

I have the honor to transmit with this the tracings+ of Dutch Gap, which should accompany last month's report, together with a section of the signal tower lately erected on the James River.

Very respectfully, your obedient servant,

PETER S. MICHIE,

Lieutenant and Acting Chief Engineer.

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*Not found.

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+See Michie's report, September 10, 1864.