It is certain that the whole of Longstreet's grand corps, comprising the entire division of Pickett, Hood, and French, were engaged in the first advance on Suffolk, well as Jenkins' division, of the Blackwater, troops, who took position on the Edenton road on the fourth day of the siege.

The disposition of rebel force during the first two weeks of the siege was, in my opinion, as follows: Jenkins' (probably 4,000 strong) mainly in position on the Edenton road near Darden's Mill; Pickett's division (of four brigades) on the Somerton road, his right meeting Jenkins' left in the woods between the Edenton and Somerton; Hood's division on the South Quay, connecting with Pickett opposite Fort Nansemond; French on the Providence Church road and river line.

During the pursuit of the enemy, on the morning of their retreat (May 4), we ascertained beyond the possibility of a doubt that on May 1 or 2 two brigades of North Carolina troops (Garnett's and another) joined Pickett, and encamped with him on the Somerton. During that pursuit nearly 300 prisoners were captured from forty different regiments, all of which had been encamped on the Edenton and Somerton roads, and were from Jenkins' and Pickett's division and the two North Carolina brigades exclusively.

These prisoners rather increased than diminished the previous estimates of the enemy's strength and confirmed fully the statements of deserters and people residing in the vicinity.

The vast and formidable lines of the enemy's works could not have been constructed in twenty-three days by lees than 35,000 troops, considering the constant state of activity in which they were kept by the movements of our forces. Our own troops were incessantly engaged in fatigue duty, and certainly performed less than one-fourth of the labor done by the enemy.

I am convinced by the foregoing facts the enemy under command of Longstreet during the investment of Suffolk was not less than 34,000 men, exclusive of Hill's re-enforcements.

I am, major, yours, very respectfully,

MICHAEL CORCORAN,

Brigadier-General.

Major B. B. FOSTER,

Assistant Adjutant-General.

Numbers 7. Report of Major Alexander G. Patton, First New York Mounted Rifles, of skirmish on the Edenton road, April 15.

CAMP FIRST MOUNTED RIFLES,

Suffolk, va., April 18, 1863.

GENERAL: I have the honor to report that at 3 o'clock on the morning of the 15th instant I left this camp to make a reconnaissance on the Edenton road, to attack the enemy, and, if possible, to ascertain his force. My command consisted of Company E, Captain Gregory; Company M, Captain Masten, and one howitzer, in charge of Corporal McConnoll, of Company D, all of this regiment. At Fort Dix I was joined by Colonel McMahon with two companies of infantry.

We proceeded cautiously for some 2 1/2 miles, when having approached near to the enemy's pickets, I directed one shot to be fired from the