lives 3 miles below Budd's Ferry, and who has a brother in the rebel camp opposite. The two brothers are in constant communication.

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

R. S. WILLIAMSON

Captain, U. S. Topographical Engineers.

Brigadier General S. WILLIAMS,

Asst. Adjt. General, Div. of the Potomac, Washington, D. C.

CAMP, FIVE MILES ABOVE BUDD'S FERRY,

October 29, 1861.

GENERAL: General Hooker has informed me that he has had a conference with the commanding officer of the naval forces on the Potomac, and that it has been deemed expedient to throw up some earthworks in the vicinity of Indian Head to prevent the rebels from erecting batteries on the opposite shore. I was directed to examine the locality by General Hooker, which I did yesterday. I found that at the mouth of Mattawoman Creek the land is low and swampy, but that at some little distance above it rises, forming a bluff some 2 miles in length and from 60 to 120 feet high. The bluff or cliff has very steep sides, and abuts directly upon the water. The land on the opposite side of the river is much lower, being, according to my estimate, from 20 to 40 feet high. The Coast Survey map makes the river in this vicinity 2 1/2 miles wide, but I can scarcely believe it to be more than 1 1/2 miles, and this is the estimate of the commodore.

At the first high land above Mattawoman Creek a battery can be erected, some of the guns from which will give a fire down the river, while others will fire across it. Just above this the bluff is broken by a ravine, and a road now runs through it to the river. Above the ravine the bluff continues as described (but with increased altitude) without interruption for 1 1/2 or 2 miles, when it terminates, and where there are two wharves within 100 yards of each other, where vessels drawing 10 feet of water can land. This is about the place marked Glymont on the Coast Survey map of the river. The deep water is near the left of this bank of the river. The land is higher above the ravine than below it, and at about a quarter of a mile above it the edge of the bluff is higher than farther inland, forming a gentle slope in that direction. There is there space enough on good ground for the camp of a regiment of infantry, with water from the ravine near by. At this place I would break ground. If the works to be erected do not require protection from the rear, a simple parapet can be built along the edge of the cliff, where as many guns can be place as may be required. The fire from them will be across the river, though, as some parts of the cliff are higher than others, it will be possible at some few points to command a fire up or down the stream. Subsequently a detached work can be erected below the ravine. This description will, I hope, give you the general character of the ground, and enable you to decide upon the nature of the erection. There is no known rebel battery near.

This letter is submitted to General Hooker before forwarding it.

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

R. S. WILLIAMSON,

Captain, U. S. Topographical Engineers,

Brigadier General S. WILLIAMS,

Asst. Adjt. General, Division of the Potomac, Washington, D. C.