The necessity of the continual detachment of bodies of troops to watch the enemy on the left being obviated, we could throw a greater force on the more prominent points of attack. The opening of the Baltimore and Ohio Railway, the protection of a Union sentiment wherever manifested, and the importance of guarding the base of our operations alike point to the apparent necessity of the measure indicated, which, I trust, will appear a sufficient excuse from presenting it to your attention.

I am, very respectfully, your obedient servant,

GEO. B. McCLELLAN,

Major-General.

HAGERSTOWN, MD., June 29, 1861.

Colonel E. D. TOWNSEND,

Asst. Adjt. General, Washington City:

COLONEL; I inclose, for the information of the General-in-Chief, Captain Newton's report of his examination of the Maryland Heights. The report is not as full as I desired it to be, due to its being rapidly made, in consequence of having to send him of suddenly. From conversation with him and information I gain from residents, I am convinced the occupation of the heights would be attended with great labor, and unless a strong force be placed in Pleasant Valley to keep open communications with water, it cannot be held at this season by any command opposed.

I inclose also a communication from Captain Newton, relating to the reoccupation of these heights. I do not think the information reliable. Considerable force had been seen in the vicinity of Shepherdstown.

I arranged to-day to advance into Virginia on Monday. This is the earliest I can move with artillery, without which I deem it very imprudent to cross the river, with information of a large opposing force close at hand. I expect to drive the enemy from our vicinity, and, should it appear advisable, will push to Winchester. If the enemy have retired (which his demonstrations may have prepared for), you will next hear of my approach to you.

I am, sir, very respectfully, your obedient servant,

R. PATTERSON,

Major-General, Commanding.

[Inclosures.]

HAGERSTOWN, MD., June 25, 1861.

Major F. J. PORTER,

Assistant Adjutant-General:

SIR: I have the honor to report the result of my examination of Maryland-Heights (Elk Ridge).

I ascended first the western slope by the country road leading to Solomon's Gap; thence I proceeded on the summit four miles to the southern extremity of the ridge. This road requires extensive repairs for heavy hauling for a distance of about four miles.

The top of the ridge is covered with a small growth of timber and brushwood, and is difficult of penetration. An easy defense could be made by cutting down the timber and brush across the summit for about two hundred yards in width, and forming behind this obstruction a light parapet, having the interior slope stockaded, the stockade to be height enough to protect the heads of the men when standing on the banquette, and to beloop-holed. Other stockaded parapets amy be erected whenever a more minute examination may render it necessary and at