southeastern point is a promontory, connected by a narrow neck of land with the main body of the island. This promontory is about forty feet above the water at its highest point, and diminishes in altitude to the neck, which in the lowest point is from fifteen to twenty feet above its bluff banks. The soil is of clay and easily excavated. THis point would be admirably adapted to give a cross- fire with Alcatraz, a fire in the direction of the Golden Gate, and of the entrance to Raccoon Straits, but it is too small to admit of a work of any size. Not more than six or ten guns could be advantageously placed there, protected bay a suitabnle parapet. On the main portion of the island, just back of the promontory, the ground gradually rises for a little distance, and then more rapidly until it attains an altitude of several hundred feet. On the slope o this ascent any desired number of guns can be placed in battery. I have been unable to find as yet any map of the island that gives more than its outline. Perhaps a detailed map or a survey would modify the views I have expressed as to the extent of the promontory, &c. The open ground on and near the neck of land being open and but of gentle acclivity, would aford good ground for a camp of one company or for a military post.

OLike al the islands in the bay, this one is of a rugged character with steep bluffs rising from the water. In most parts the water is deep near the shore, but int he little bays that indent the shore the water is shallow. At the neck of land so often referred to is a good location for a wharf, which would probably require not more than a lengtyh of 150 feet to give 10 feet of water at low tide. There are several houses on the island, but the land has ben acknowledged indisputabley to be a Government reserve. In consequence of a very high wind and thick fog I did not visit the western side of the island, but from information obtained from one of the residents I learned that the southwest point, at the entrance to Raccoon Straits, is an excellent place for a battery. THis andthe southeast point are fully one mile and half apart in a straight line, and the rugged nature of the island sould make a good road between them expensive. This and the distance would probably make it necessary to have two separate and distinct posts with separate landing places, &c., if a battery is to be erected on both points. Yout 21 directs the rection of one battery on Angel Island, but does not indicatewhere. I respectfully request instructions as to which extreminty of the island the battery should be rected. The general informed me that he intneded to send a compamy of artillery this week to occupy the island. Will they be furnished with tents, or is the quartemaster to build barracks for tehm!

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

R. S. WILLIAMSON,

Captain, U. S. Engineers.

[Indorsement.]

Respectfully referred to Colonel De Russy.

As soon as the position is determined upon a company will be sent to Angel Island to assist in erecting the work, tools, &c., being furnished by the Engineer Deaprtment.

By order of Brigadier-General Wright:

R. C. DRUM,

Assistant Adjutant-General.