The sketch below gives the idea roughly:

(MAP*)

I will send plans promptly, but in case my occupations, which are now very heavy, should prevent, I feel assured the engineers in your command can arrange the details. By keeping sand bags filled, on hand, your guns can in a few minutes be protected against iron-clad boats. These bags could be thrown off rapidly should a wooden fleet attempt to pass with troops, and I believe in that case the bluff batteries fully equal to the water batteries.

You will readily infer from what I have written that I think your water communication with West Point in great danger. I shall exert myself to have the Gloucester Point guns mounted promptly and properly.

Colonel Carter can communicate more fully the result we have arrived at.

With great respect, your obedient servant,

ALFRED L. RIVES,

Acting Chief Engineer Bureau.

HEADQUARTERS,
Young's Mill, March 12, 1862.

General S. COOPER,

Adjutant and Inspector General, Richmond:

SIR: I have the honor to report that I send Sergeant Tabb, a most intelligent man, who is on signal service in this department and was a volunteer on board of the Virginia in the late action, to reconnoiter Newport News in a boat yesterday afternoon, and he has just returned, stating that whilst in front of Newport News the Ericsson came up from Fort Monroe with some troops on board and landed them at Newport News; that a very large force was at that place and increasing. Their pickets have advanced some mile and a half up the river, and I am satisfied that they mean to march up on the left bank of James River, sending the Ericsson to silence the guns in the river batteries, and thus freeing the river of the passage of transports with other troops and forcing us to fall back by ascending the river. It may require some little time to do this, but they will succeed in the end, unless the Virginia can leave the dock and prevent the Ericsson from coming up. The latter vessel draws, I am informed, much less water than the Virginia, and if she once gets up the Virginia could not follow her, as there is a bar below Day's Neck, I am told by James River pilots, on which there is not more than 18 feet water, and the Virginia draws 22 feet.