nature of the country, hence I did not arrive here before the infantry. I have no information as to the rebel force here except what I see. Some men seen on the route say the rebels in very small parties are in the habit of visiting this side every night. Others say (and those here) that they have been here but once, when they destroyed a vessel in the creek near by. People here are said to be generally secessionists, but they say nothing.

As soon as I make the measurement of the river and gain any other information I will report.

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

R. S. WILLIAMSON,

Captain, U. S. Topographical Engineers.

Brigadier General R. B. MARCY,

Chief of Staff of General McClellan, Washington, D. C.

CAMP NEAR MATTAWOMAN CREEK,

Five miles north of Budd's Ferry, October 25, 1861.

GENERAL: I have the honor to report that I started early yesterday morning from a camp near this place, and with a small escort returned to Budd's Ferry, and succeeded in completing the measurement of a base line and triangulating across the river. The line measured was 7,800 feet long, and no part of it distant from the river more than 150 yards.

I find that the batteries at Evansport, at the mouth of Quantico Creek, are nearer to this shore than the one at Shipping Point by 100 yards, and that the former are 7,800 feet from the nearest point of this shore, or a short 1 1/2 miles (1,48 miles). The two batteries are 1,400 feet apart. I find also that directly opposite the nearest battery there is a point which sightly projects farther than the general line of the shore, and there the ground is a little higher than above or below, being about 15 feet above the water. If a battery is to be placed opposite those of the rebels, this point should be selected. There is a thin line of trees at that point, but not enough to produce an efficient cover.

I mentioned in a former letter that the general character of the shore for 1 1/2 miles opposite the rebel batteries is a slightly elevated bank, extends from three-quarters of a mile to a mile from the river, where there is a bluff from 50 to 100 feet high, affording good sites for mortar batteries. They can be constructed in timber to afford shelter, and the timber subsequently cleared away.

The two batteries opposite Budd's Ferry are said to be the most important ones on the river, but there are many others. There is a battery at the mouth of Chopawamsic Creek, the size of which I could not ascertain with my glass, but I saw a flag flying there yesterday and about 100 men in its vicinity.

I have found a man by the name of Anderson, who knows every road and lane about here, and the name and character of each inhabitant, and I have engaged him as a guide,at $1.50 per day. I hope this will be approved of. He says the rebels knew of our arrival near Budd's Ferry on the day we reached there. He says also it is the intention of the rebels to go from Richmond to the mouth of Aquia Creek by railroad, and then cross over to Smith's Point. This is to be done in a week or two. Mr. Anderson learned this yesterday from a friend who