OMAHA, NEBR. TER., August 20, 1864.

Brigadier General ROBERT B. MITCHELL:

Lieutenants Schenck and Williams leave this morning. First Nebraska arrived at columbus at 9 p. m. last night.

JNO. PRATT,

Assistant Adjutant-General.

OMAHA, August 20, 1864.

Colonel R. R. LIVINGSTON,

Columbus (or next telegraph station):

McClellan left 19th; Ribble and Curran 18th. Weatherwax, retained here by Major Blacker, goes to-day with detachment of twenty men. Communicate at telegraph stations with General Mitchell, at Kearny.

JNO. PRATT,

Assistant Adjutant-General.

FORT LEAVENWORTH, August 20, 1864.

Colonel J. M. CHIVINGTON,

Denver City:

Your dispatch of yesterday received and forwarded to General Curtis. Ammunition train (nine wagons) for Denver loaded on the 12th instant; probably by this time somewhere in the vicinity of Marysville.

C. S. CHARLOT,

Major and Assistant Adjutant-General.

MILWAUKEE, August 20, 1864.

Brigadier-General SIBLEY,

Saint Paul:

Please keep me advised frequently of the condition of affairs on the frontier. I trust you have already written. A full regiment is on its way to this department. If necessary, I will send some of them to Minnesota.

JNO. POPE,

Major-General, Commanding.

HDQRS. DIST. OF MINNESOTA, DEPT. OF THE NORTHWEST,
Saint Paul, Minn., August 20, 1864.

Major General JOHN POPE,

Commanding Department of the Northwest, Milwaukee, Wis.:

GENERAL: I have the honor to state that no further information has been received relative to Indian outrages, although there is no reason to doubt that a body of warriors more or less formidable in numbers is on this side of the Big Sioux River, waiting an opportunity to strike at some unguarded point. The available force I have has been distributed so as to protect as many points as possible, but I have so large a portion of my cavalry engaged in escort duty between Forts Ridgely and