KANSAS CITY, MO., August 5, 1863.

Colonel McFERRAN,

Commanding Lexington, Mo.:

Quantrill's band will assemble on Friday, the 7th, about 10 a.m., in the vicinity of Texas Prairie; exact locality not known. Our forces will press him from the west. Send all your available force to Texas Prairie, near the Peacock place,where the Boyins family live, 3 miles southeast of Lick Skillet. One company should be sent to road leading from Round Prairie to Chapel Hill, near the old Canada place. The balance of your force,taking care to keep your communications perfect and you forces within supporting distance, should be so employed in making reconnaissances as to be certain that no enemy passes to your rear. Do not come farther west than Lone Jack.

By order of Brigadier-General Ewing:

P. B. PLUMB,

Major and Chief of Staff.

HEADQUARTERS DEPARTMENT OF THE NORTHWEST, Milwaukee, August 5, 1863.

Brigadier General ALFRED SULLY,
Commanding Indian Expedition:

GENERAL: I have just received your letter of 27th instant, and I assure you it both surprised and disappointed me. I never had the slightest idea you could delay thus along the river,nor dot I realize the necessity of such delay. You have 100 wagons, &c., sent from Saint Louis and about 20 with the Sixth Regiment from Iowa. I supposed, of course, that knowing,as my letters both to you,and General Cook (your predecessor)have time and again informed you, how necessary it was that you should be in position on the Upper Missouri, or between that river and Devil's Lake, to co-operate with General Sibley, you would have unloaded any heavy baggage you have, and have loaded your wagons with subsistence stores and have pushed on without delay. I never dreamed you would consider yourself tied to the boats if they were obstacles in going up the river. As matters stand, it seems to me impossible to understand how you have staid about the river, delaying from day to day,when time of all things was important, and when you had wagons enough to carry at least two months' subsistence for your command.

If you have adopted this course before this letter reaches you, please do so at once, and move rapidly up the river. Leave all your baggage, and load your wagons with subsistence. Such a failure as you anticipate must not happen, as it will be impossible for you to explain it satisfactorily.

Sibley has had equal difficulties with yourself, but he reached Devil's Lake about the 22nd, and I should not be surprised to hear of him on the Missouri above you.

If the Indians are driven into the British possessions, where we cannot follow them, we will have done all in our power, and no one can be dissatisfied; but this much must be done. I trust that you will realize the important of what I here say to you, and will act upon it promptly and fully. Your forces consist entirely of cavalry, and there can be no reason why you should not be able to execute the object of your expedition.

Respectfully, general, your obedient servant,

JNO. POPE,

Major-General, Commanding.