mediate vicinity also is a strong commanding ridge on the line of approach from Petersburg to Richmond.

In regard to the line of the Chickahominy, I can as yet make no definite report, although an officer is on duty in its examination. the recent calls for engineers by General Johnston and others have left me but limited professional resources. I have heard, however, that Colonel Talcott, Chief of the Virginia Engineer Corps, examined this line, but did not think very favorably of it. It may, however, be possible to erect, in a reasonable time, a series of dams, with properly-constructed covering works, which would add greatly to the strength of the Richmond defenses on the north. As soon as the surveys are completed a full report will be promptly made.

The James River defenses, which are rapidly improving, afford already a good protection against wooden fleets, but not against iron-clad vessels. From recent developments it is evident that nothing but the very heaviest ordnance, and that in connection with obstructions and perhaps torpedoes, can contend successfully with this latter class. it is to such means we are resorting on the James River. In positions similar to those of Fort Huger, Yorktown, and Mulberry Island Point the only course left to pursue seems to be to mount the guns on the bluffs, where they are not liable to be struck, or in well-constructed casemates, to contend with wooden ships, keeping sand bags ready filled to protect them against iron-clad vessels. This class is so excessively expensive and confined as to be ill-adapted to the transportation of troops in large numbers. The effect, however, of passing our lower batteries by preventing the safe navigation of our rivers above them will probably to be force us at no distant day to rely in great measure on land transportation.

A mistaken impression on my part that this report was called for on the termination of the surveys has led to this delay, for which it is the only excuse.

With great respect, your obedient servant,

ALFRED L. RIVES,

Acting Chief Engineer Bureau.

ENGINEER BUREAU,

Richmond, March 12, 1862.

General J. BANKHEAD MAGRUDER,

Commanding Army of the Peninsula:

GENERAL: Colonel Carter, who will hand you this, submitted to me Captain Dimmock's report, approved by himself and addressed to you. From the experience derived in the recent contest between the Virginia and Monitor it is evident to me that water batteries in the immediate vicinity of deep water should be abandoned at once - those at both Yorktown and Gloucester Point. I unhesitatingly recommend such a step, only leaving a masked battery of the smallest pieces to protect the beach and communicating with the works on the bluffs by a covered way.