OFFICE OF THE CHIEF ENGINEER, DEPT. OF THE GULF,

New Orleans, La., January 22, 1864.

Major-General BANKS,

Commanding Department of the Gulf:

GENERAL: I have the honor to submit the following information concerning the routes from the Mississippi River to the interior o Texas: Brashear City to Alexandria, 174 miles; Brashear City to Shreveport, 344 miles; Simsport to Alexandria, 70 miles; Natchez to Alexandria, via Harrisonburg, 80 miles; Natchez to Natchitoches, 120 miles; Vicksburg to Shreveport, 148 miles; Little Rock to Shreveport,225 miles; Fort Smith to Shreveport, 300 miles; Alexandria to Shreveport, 170 miles; Alexandria to Houston, 270 miles; Shreveport to Houston, 295 miles.

The water via Red River commences falling about the 1st of May, and the navigation of the river for the most of our gun-boats and transports is not reliable after that time. The months of March and April are unfavorable for operations in Northern and Eastern Texas, owing to the high stage of water in the Sabine, Neches, and Trinity Rivers, and their tributaries, and the overflows to which their banks are subject. The concentration of all the forces available for operations west of the Mississippi in the vicinity of Shreveport requires that the line of supply with the Mississippi be kept you. It would not be practicable to abandon the base with so large a force, with a line of operations of 300 miles, through a country occupied by the enemy, to be overcome before communication could possibly be effected with points held by us on the coast.

The water communication to Alexandria cannot be depended on after the 1st of May, and it would be necessary to depend on the road from Natchez, a distance of 80 miles, or possibly from Harrisonburg, a distance of 50 miles. Boats of very light draught, say 3 or 3 1/2 feet of water, may go to Alexandria during low water at ordinary seasons, but the large majority of our boats and gun-boats are of greater draught than this. The most reliable routes would be by the railroad from Vicksburg to Shreveport. The track is now laid from Vicksburg to Monroe. The road is graded from Monroe to Shreveport, and mostly bridged; the distance is 96 miles. There is a good wagon road from Monroe to Shreveport, crossing the Washita River and other streams.

It would require at least three months to rebuild this railroad, which is indispensable to the supply of an army in Northeastern Texas. To insure success and permanent results to the operations of a force to operate against Texas, or, rather, against the rebel forces west of the Mississippi, it is essential that the forces available for this purpose, viz, those now west of the Mississippi, and any additional forces that may be assigned, should be placed under the command of a single general. The rebel forces west of the Mississippi have a single head, and so should the forces operating against them. Preparations should be made to establish a line of supply, independent of he water-courses; otherwise, by the time the forces are concentrated and ready to move forward, they, will be compelled to halt until a new line of supply is established thus giving the enemy a breathing spell and an opportunity to harass our communication with their mounted troops.

It is of vital importance, in operation of this kind, where the distances traversed are so great, that there should be no delays, for our