Grove Wharf. That there is much Union feeling among the poorer classes on the York and Rappahannock Rivers, especially among the oysterman and fisherman.

All of which is respectfully submitted by your obedient servant,

E. J. ALLEN [ALLEN PINKERTON].

Major General GEORGE B. McCLELLAN,

Commanding U. S. Army.

HEADQUARTERS ARMY OF THE POTOMAC,
Camp at Yorktown, May 3, 1862.

GENERAL: I have the honor to report the following information relative to the forces and defenses of the rebel Army of the Potomac and also of the rebel Army of the Peninsula, obtained to date, which has been extracted from current statements made at these headquarters by spies, contrabands, deserters, refugees, and prisoners of war, in the order of time as hereinafter indicated, and which at the time of reception were made the subject of special reports to you; that portion of this report having reference to the rebel Army of Potomac as included in the summaries relative thereto being also derived in part from previous reports made to you in reference to the rebel Army of the Potomac. I have also appended to this report a varied summary of those forces and defenses, showing by different combinations about the probable number of these forces and the locality and strength of their defenses.

The summary of general estimates of the rebel army at Yorktown shows their forces to date of latest information to be 100,000 to 120,000, such being the medium estimates, and taken from statements deemed most reliable, the information upon which they are based having been derived from officers of their army and from persons connected with their commissary department at Yorktown, the latter of whom stated the daily rations issued there to be 119,000. The summary also shows that specific information has been received of twenty-two different known brigades, forty-five regiments, and three battalions infantry, two regiments cavalry, one legion of 2,500 men, and ten companies artillery, which specific information, though forming but a small portion of the rebel army, is all that it has been possible to obtain, owing to want of time and the very rapid and continued accumulation of troops at this point re-enforcing their army. It may, however, safely be assumed that the medium estimates stated (100,000 to 120,000) are under rather than over the mark of the real strength of rebel forces at Yorktown.

It is also shown by statements in the report that rebel re-enforcements at Yorktown commenced to arrive on the 25th March in considerable numbers, and have continued arriving ever since to date of latest information, one brigade having landed at King's Mill, James River, on the 1st instant.

All of which, general, is respectfully, submitted, by your obedient servant,

E. J. ALLEN.

Major General GEORGE B. McCLELLAN,

Commanding Army of the Potomac.