SIMSPORT, May 19, 1864.

 Maj. C. T. CHRISTENSEN,
Asst. Adjt. Gen., Division of West Mississippi:

MAJOR: In compliance with letter from headquarters Division of West Mississippi to Major-General Banks, of 18th instant, referred to me, I have the honor to submit the following report: The troops available for engineer operations in this department are one company of pontoniers (white) and five regiments (colored). The pontonier company, Capt. J. J. Smith, has been enlisted about two months. It has its own train, with tools and wagons and 180 feet of bateau bridge complete. It is under the orders of the chief engineer of the department. It is now with the army in the field. The five regiments are the Ninety-fifth, Ninety-sixth, Ninety-seventh, Ninety-eighth, and Ninety-ninth U.S. Infantry (colored). They have habitually been under the orders of the chief engineer of the department, except when temporarily assigned by the major-general commanding to some general in the field. Each has its own regimental train only, and when put in the field is furnished also with intrenching and some mechanics' tools.

These regiments are now disposed as follows: The Ninety-fifth constructing and repairing field-works at and near Brownsville, Tex., on plans furnished by its own officers. It is now under the orders of the chief engineer. The Ninety-sixth is similarly employed at and near Pass Cavallo. I understand this part of Texas has been evacuated, and infer, without knowledge, that this regiment is now awaiting orders near New Orleans, in which case I shall recommend that it be sent to Port Hudson. The Ninety-seventh and Ninety-ninth U.S. Infantry (colored) constitute the Engineer Brigade in the field, under command of Col. G. D. Robinson, of the Ninety-seventh. They have 28 wagons and 270 spades, 245 picks, 790 shovels, and 425 axes and 4 chests carpenter tools. I inclose the last orders received concerning them (Field Orders, Nos. 4 and 30), by which they appear to be under command of Colonel Bailey, chief  engineer Nineteenth Army Corps. The Ninety-eighth U.S. Infantry is constructing field-works at Berwick City,  on plans furnished by the chief engineer, under whose orders it is. After this work is completed, it is intended to send the regiment to Port Hudson to finish the work there.

In New Orleans is a new canvas advance-guard boat train, about 600 feet long, with its wagons and equipage complete. With the Ninety-fifth U. S. Infantry (colored), at Brownsville, is about 80 feet of an old India-rubber pontoon bridge, so worn as to be nearly useless, and quite unfit to be sent into the field. Other remains of the same bridge are in New Orleans. With the Ninety-sixth U.S. Infantry (colored), at Pass Cavallo, are 200 feet, and with the Ninety-eighth U.S. Infantry (colored), at Berwick City, are 100 feet of the same wooden bateau bridge, of which the 180 feet with Captain Smith's pontoniers have been already mentioned. These are all the bridge trains in the department. A captain and acting assistant quartermaster assigned to the engineer department procures from the chief quartermaster of the department such tools and materials as he can, and keeps them on hand in New Orleans, or expends them on the field-works, and attends to their transportation. Others are paid for by myself, with funds furnished me by the U.S. Treasurer at Washington, on my estimates and requisitions, approved by the Chief Engineer of the U.S. Army at Washington Such funds can only be expended for the works for which they are remitted, and are not available for the wants and uses of an army in the field. The colored troops have had some experience in bridge building and construction of earth-works, but are ignorant of all sapping and mining, and could only be useful as laborers in the operations of a siege with their present instruction.

Respectfully submitted.

 JOHN C. PALFREY,