In giving these orders of march for the 4th and 5th, it was expected that there would be no serious opposition at Big Bethel, and that the advance of the 3d corps beyond that point would force the enemy to evacuate the works at Young's mills, while our possession of the latter would make it necessary for him to abandon those at Howard's bridge, and the advance thence on Yorktown would place Ship point in our possession, together with its garrison, unless they abandoned it promptly. The result answered the expectation.

During the afternoon of the 4th, General Keyes obtained information of the presence of some 5,000 to 8,000 of the enemy in a strong position at Lee's mills. The nature of that position in relation to the Warwick not being at that time understood, I instructed General Keyes to attack and carry this position upon coming in front of it.

Early in the afternoon of the 5th the advance of each column was brought to a halt, that of Heintzelman (Porter's division) in front of Yorktown, after overcoming some resistance at Big Bethel and Howard's bridge; that of Keyes (Smith's division) unexpectedly before the enemy's works at Lee's mills, where the road from Newport News to Williamsburg crosses Warwick river.

The progress of each column had been retarded by heavy rains on that day, which had made the roads almost impassable to the infantry of Keyes's column, and impassable to all but a small portion of the artillery, while the ammunition, provisions and forage could not be brought up at all.

When General Keyes approached Lee's mills his left flank was exposed to a sharp artillery fire from the further bank of the Warwick, and upon reaching the vicinity of the mill he found it altogether stronger than was expected, unapproachable by reason of the Warwick river, and incapable of being carried by assault.

The troops composing the advance of each column were, during the afternoon, under a warm artillery fire, the sharpshooters even of the right column being engaged when covering reconnoissances.

It was at this stage and moment of the campaign that the following telegram was sent to me:

"By direction of the President, General McDowell's army corps has been detached from the force under your immediate command, and the general is ordered to report to the Secretary of War. Letter by mail.

"General McCLELLAN."

"L. THOMAS, Adjutant General.

The President having promised, in an interview following his order of March 31, withdrawing Blenker's division of 10,000 men from my command, that nothing of the sort should be repeated-that I might rest assured that the campaign should proceed, with no further deductions from the force upon which its operations had been planned-I may confess to having been. shocked at this order, which, with that of the 31st ultimo and that of the 3d, removed nearly 60,000 men from my command, and reduced my force by more than one-third, after its task had been assigned; its operations planned; its fighting begun. To me the blow was most discouraging. It frustrated all my plans for impending operations. It fell when I was too deeply committed to withdraw. It left me incapable of continuing operations which had been begun. It compelled the adoption of another, a different and a less effective plan of campaign. It made rapid and brilliant operations impossible. It was a fatal error.

It was now, of course, out of my power to turn Yorktown by West Point. I had, therefore, no choice left but to attack it directly in front, as I best could with the force at my command.

Reconnoissances made under fire on that and the following day determined that the sources of the Warwick river were near Yorktown, commanded by its guns, while that stream, for some distance from its mouth on the James river, was controlled by the confederate gunboats; that the fords had been destroyed by dams, the approaches to which were generally through dense forests and deep swamps, and defended by extensive and formidable works; that timber felled for defensive purposes and the flooding of the roads, caused by the dams, had made these works apparently inaccessible and impossible to turn; that Yorktown was strongly fortified, armed and garrisoned, and connected with the defences of the Warwick by forts and intrenchments, the ground in front of which was swept by the guns of Yorktown. It was also ascertained that the garrisons had been, and were daily being re-enforced by troops from Norfolk and the army under General J. E. Johnston. Heavy rains made the roads to Fort Monroe impassable, and delayed the arrival of troops, ammunition and supplies, while storms prevented for several days the sailing of transports from Hampton roads, and the establishment of depots on the creeks of York river, near the army.

The ground bordering the Warwick river is covered by very dense and extensive forests, the clearings being small and few. This, with the comparative flatness of the country, and the alertness of the enemy, everywhere in force, rendered thorough reconnoissances slow, dangerous and difficult, yet it was impossible otherwise to determine whether an assault was anywhere practicable, or whether the more tedious but sure operations of a siege must be resorted to.

I made, on the 6th and 7th, close personal reconnoissances of the right and left of the enemy's positions, which, with information acquired already, convinced me that it was best to prepare for an assault by the preliminary employment of heavy guns, and some siege operations. Instant assault would have been simple folly. On the 7th I telegraphed to the President as follows:

"HEADQUARTERS ARMY OF THE POTOMAC,

"April 7, 1862.

"Your telegram of yesterday is received. In reply, I have the honor to state that my entire force for duty amounts to only about (85,000) eightyfive thousand men. General Wool's command, as you will observe from the accompanying order, has been taken out of my control, although he has most cheerfully co-operated with me. The only use that can be made of his command is to protect my communications in rear of this point. At this time only fifty-three thousand men have joined me, but they are coming up as rapidly as my means of transportation will permit.

"Please refer to my despatch to the Secretary of War to-night, for the details of our present situation.

"To the PRESIDENT, Washington, D. C."

On the same day I sent the following:

"GEO. B. McCLELLAN,

"Major General

"Your telegram of yesterday arrived here while I was absent, examining

the enemy's right, which I did pretty closely.

"The whole line of the Warwick, which really heads within a mile of Yorktown, is strongly defended by detached redoubts and other fortifications, armed with heavy and light guns. The approaches, except at Yorktown, are covered by the Warwick, over which there is but one, or, at most, two passages, both of which are covered by strong batteries. It will be necessary to resort to the use of heavy guns, and some siege operations, before we assault. All the prisoners state that General J. E. Johnston arrived at Yorktown yesterday with strong re-enforcements. It seems clear that I shall have the whole force of the enemy on my hands-probably not less than (100,000) one hundred thousand men, and probably more. In consequence of the loss of Blenker's division and the 1st corps, my force is possibly less than that of the enemy, while they have all the advantage of position.

"I am under great obligations to you for the offer that the whole force and material of the government will be as fully and as speedily under my command as heretofore, or as if the new departments had not been created.

"Since my arrangements were made for this campaign, at least (50,000) fifty thousand men have been taken from my command. Since my despatch of the 5th inst., five divisions have been in close observation of the enemy, and frequently exchanging shots. When my present command all joins, I shall have about (85,000) eighty-five thousand men for duty, from which a large force must be taken for guards, scouts, &c. With this army, I could assault the enemy's works, and perhaps carry them; but were I in possession of their intrenchments, and assailed by double my numbers, I should have no fears as to the result.

"Under the circumstances that have been developed since we arrived here, I feel fully impressed with the conviction that here is to be fought the great battle that is to decide the existing contest. I shall, of course, commence the attack as soon as I can get up my siege train, and shall do all in my power to carry the enemy's works, but to do this with a reasonable degree of certainty requires, in my judgment, that I should, if possible, have at least the whole of the 1st corps to land upon the Severn river and attack Gloucester in the rear.

"My present strength will not admit of a detachment sufficient for this purpose, without materially impairing the efficiency of this column. FlagOfficer Goldsborough thinks the works too strong for his available vessels, unless I can turn Gloucester. I send, by mail, copies of his letter and one of the commander of the gunboats here.

"Hon. E. M. STANTON,

"Secretary of War."

"GEO. B. MCCLELLAN,
"Major General.

I had provided a small siege train and moderate supplies of intrenching tools for such a contingency as the present. Immediate steps were taken to secure the necessary additions. While the engineer officers were engaged in ascertaining the character and strength of all the defences, and the configuration of the ground in front of Yorktown, in order to determine the point of attack and to develop the approaches, the troops were occupied in opening roads to the depots established at the nearest available points, on branches of York river. Troops were brought to the front as rapidly as possible, and on the 10th of April the army was posted as follows :

Heintzelman's corps, composed of Porter's, Hooker's, and Hamilton's divisions, in front of Yorktown, extending in the order named, from the mouth of Wormley's creek to the Warwick road, opposite Winn's mills. Sumner's corps-Sedgwick's division only having arrived-on the left of Hamilton,

extending down to Warwick and opposite to Winn's mills works. Keyes's corps (Smith's, Couch's, and Casey's divisions,) on the left of Sedgwick, facing the works at the one-gun battery, Lee's mills, &c., on the west bank of the Warwick. Sumner, after the 6th of April, commanded the left wing, composed of his own and Keyes's corps.

Throughout the preparations for, and during the siege of Yorktown, I kept the corps under General Keyes, and afterwards the left wing, under General Sumner, engaged in ascertaining the character of the obstacles presented by the Warwick, and the enemy intrenched upon the right bank, with the intention, if possible, of overcoming them and breaking that line of defence, so as to gain possession of the road to Williamsburg, and cut off Yorktown from its supports and supplies. The forces under General Heintzelman were engaged in similar efforts upon the works between Winn's mills and Yorktown. General Keyes's report of the 16th of April, enclosing reports of brigade commanders engaged in reconnoissances up to that day, said, "that no part of his (the enemy's line opposite his own) line, so far as discovered, can be taken by assault without an enormous waste of life.”

Reconnoissances on the right flank demonstrated the fact that the Warwick was not passable in that direction, except over a narrow dam, the approaches to which were swept by several batteries, and intrenchments which could be filled quickly with supports sheltered by the timber immediately in rear.

General Barnard, chief engineer of the army of the Potomac, whose position entitled his opinions to the highest consideration, expressed the judg ment that those formidable works could not, with any reasonable degree of certainty, be carried by assault. General Keyes, commanding 4th army corps, after the examination of the enemy's defences on the left, before alluded to, addressed the following letter to the Hon. Ira Harris, United States Senate, and gave me a copy. Although not strictly official, it describes the situation at that time in some respects so well, that I have taken the liberty of introducing it here:

"HEADQUARTERS 4TH CORPS,

"Warwick Court House, Va., April 7, 1862. "MY DEAR SENATOR: The plan of campaign on this line was made with the distinct understanding that four army corps should be employed, and that the navy should co-operate in the taking of Yorktown, and also (as I understood it) support us on our left by moving gunboats up James river.

'To-day I have learned that the 1st corps, which by the President's order was to embrace four divisions, and one division (Blenker's) of the 2d corps, have been withdrawn altogether from this line of operations, and from the army of the Potomac. At the same time, as I am informed, the navy has not the means to attack Yorktown, and is afraid to send gunboats up James river, for fear of the Merrimack.

"The above plan of campaign was adopted unanimously by Major General McDowell and Brigadier Generals Sumner, Heintzelman, and Keyes, and was concurred in by Major General McClellan, who first proposed Urbana as our base.

"This army being reduced by forty-five thousand troops, some of them among the best in the service, and without the support of the navy, the plan to which we are reduced bears scarcely any resemblance to the one voted for.

I

"I command the James river column, and I left my camp near Newport News the morning of the 4th instant. I only succeeded in getting my artillery ashore the afternoon of the day before, and one of my divisions had 1 ot all arrived in camp the day I left, and for the want of transportation

has not yet joined me. So you will observe that not a day was lost in the advance, and in fact we marched so quickly, and so rapidly, that many of our animals were twenty-four and forty-eight hours without a ration of forage. But notwithstanding the rapidity of our advance, we were stopped by a line of defence nine or ten miles long, strongly fortified by breastworks, erected nearly the whole distance behind a stream, or succession of ponds, nowhere fordable, one terminus being Yorktown, and the other ending in the James river, which is commanded by the enemy's gunboats. Yorktown is fortified all around with bastioned works, and on the water side it and Gloucester are so strong that the navy are afraid to attack either.

"The approaches on one side are generally through low, swampy, or thickly wooded ground, over roads which we are obliged to repair or to make before we can get forward our carriages. The enemy is in great force, and is constantly receiving re-enforcements from the two rivers. The line in front of us is therefore one of the strongest ever opposed to an invading force in any country.

"You will, then, ask why I advocated such a line for our operations? My reasons are few, but I think good.

"With proper assistance from the navy we could take Yorktown, and then with gunboats on both rivers we could beat any force opposed to us on Warwick river, because the shot and shell from the gunboats would nearly overlap across the Peninsula; so that if the enemy should retreatand retreat he must-he would have a long way to go without rail or steam transportation, and every soul of his army must fall into our hands or be destroyed.

"Another reason for my supporting the new base and plan was, that this line, it was expected, would furnish water transportation nearly to Richmond.

"Now, supposing we succeed in breaking through the line in front of us, what can we do next? The roads are very bad, and if the enemy retains command of James river, and we do not first reduce Yorktown, it would be impossible for us to subsist this army three marches beyond where it is now. As the roads are at present, it is with the utmost difficulty that we can subsist it in the position it now occupies.

"You will see, therefore, by what I have said, that the force originally intended for the capture of Richmond should be all sent forward. If I thought the four army corps necessary when I supposed the navy would co-operate, and when I judged of the obstacles to be encountered by what I learned from maps and the opinions of officers long stationed at Fort Monroe, and from all other sources, how much more should I think the full complement of troops requisite now that the navy cannot co-operate, and now that the strength of the enemy's lines and the number of his guns and men prove to be almost immeasurably greater than I had been led to expect. The line in front of us, in the opinion of all the military men here, who are at all competent to judge, is one of the strongest in the world, and the force of the enemy capable of being increased beyond the numbers we now have to oppose to him. Independently of the strength of the lines in front of us, and of the force of the enemy behind them, we cannot advance until we get command of either York river or James river. The efficient co-operation of the navy is, therefore, absolutely essential, and so I considered it when I voted to change our base from the Potomac to Fort Monroe.

"An iron-clad boat must attack Yorktown; and if several strong gunboats could be sent up James river also, our success will be certain and complete, and the rebellion will soon be put down.

"On the other hand, we must butt against the enemy's works with heavy artillery, and a great waste of time, life, and material.

H. Ex. Doc. 15- -6