HEADQUARTERS SAN ANTONIO, TEX.,
April 17, 1861.

Honorable L. P. WALKER,

Secretary of War, Confederate States of America:

SIR: The news by main this morning indicates clearly that war exists between our Government and that of the United States. the commissioners of Texas agree with General Twiggs that the United States troops then in Texas might pass out of the State with their arms. At that time war did not exist. Things have changed. There are seven companies of troops still in Texas, and some of them may be now on their way from El Paso to this point. Is it proper and right now to permit them to pass through this portion of the territory of the Confederate States with their arms, embodied as United States troops, when their Government is at war with ours? In a few days more I will have six companies of troops here ready for the field, anxious to render service to their country, and with your permission-yes, without I receive orders to the contrary from your Department-with the lights now before me, think I shall require them to surrender their arms and disperse. It will e several days before they will be able to reach this place, and it would gratify me much to receive the information by telegraph through New Orleans that I have the consent of the Government to pursue the course I have indicated.

Most respectfully, your obedient servant,

H. E. MCCULLOCH,

Colonel, Commanding.

MONTGOMERY, ALA., April 20, 1861.

The Honorable SECRETARY OF WAR:

SIR: The frontier defenses of Texas geographically divide themselves into the line of the Rio Grande and the line of the western frontier-the first, from the mouth of the Rio Grande to Fort Duncan, some there hundred and fifty miles; the second, from the Rio Grande to Red River, some five hundred miles. Brownsville, Ringgold Barracks, Forts McIntosh and Duncan, commanding the lines of communication with Monterey and Victoria, and would be the base of operations for an enemy operating from Mexico. Fort Duncan, within a radius of forty miles, includes some flourishing Mexican towns, a good corn-producing region, and is on the direct line of communication from Chihuahua to San Antonio.

The line of the Rio Grande is alone exposed to Indian depredations from its upper or norther extremity. The absence of grass renders the subsistence of cavalry on this line extremely difficult, and should the supply of corn from Mexico be intercepted, almost impossible.

The points indicated on the line of the Rio Grande should, therefore, be occupied by infantry and artillery. Regulars or well-disciplined troops should alone be employed, that amicable relations may be maintained with Mexico.

If the lien of the Lower Rio Grenade is to be maintained, Fort Brown should be fortified and batteries thrown up at Brazos Santiago and the mouth of the Rio Grande. These works can be of a temporary nature-field works. Besides the artillery companies for the works at Fort Brown and the mouth of the river one regiment of infantry, distributed as follows, should be sufficient for the defense of the line of the Rio Grande: