IRONTON, MO., August 27, 1861.

ASSISTANT ADJUTANT-GENERAL,

Department of the West, Saint Louis, Mo.:

SIR: Brigadier General B. M. Prentiss left here this forenoon in pursuance of your ordered, taking all the troops here except my regiment, the First Nebraska, and the Twenty-first Illinois, and a few companies now occupied in guarding the bridges of the Iron Mountain Railroad.

The Twenty-first Illinois is at Marble Creek, some 12 miles southward on the Greenville road. This regiment is without transportation. I shall send all the teams I can procure for it to return with in the morning.

For the present, several companies of the two regiments now here having been detached for railroad guard duty, the command is in a state of great weakness. We are far too much extended for our numbers. but the importance of holding all the positions now occupied, coupled wither the certain expectation of being re-enforced before morning, together with the want of transportation, has induced me to remain as we are. If the two promised regimens fail to reach me by morning, I shall deem it my duty to contract our limits, taking care to remove the guns back within the lines.

I am under no apprehension of an attack to-night, because, though the rebels are quickly informed of our movements and condition, it is impossible for them to have received intelligence at Boliger's and Greenville in time, after General Prentiss left, for them to reach us to-night.

A well-known Union man from Cedar Creek, Mr. Edward Settle, came in this evening. He says the reels are encamped at Blinger's Mill, in command of Jeff. Thompson, who proposes, in conjunction with Hardee, to take this place. It is believed here among the more intelligent southern sympathizers that McCulloch is also advancing on this point, and that we will here have to oppose a large force. I am satisfied it is the settled opinion of those men that there will be a most formidable attack here before many days. The importance of this opinion arises from the fact that they have means of knowing, while we are in ignorance of the enemy's movements.

The squadron of 150 horse arrived this afternoon and will be sent forward to-morrow to General Prentiss. Could they be retained, the position and probable numbers of the enemy might soon be ascertained with some degree of certainty. There is much in the drift of circumstances, taken in connection with the fact that they subsist by taking everything in the country, to indicate the concentration in and around here of an army many times larger than had been deemed possible for them.

I am not aware that any inquiry has been ordered in the case of Colonel Hecker, nor what, if anything, has been done in the premises. There are no papers left me touching the matter.

I am, sir, respectfully,

P. E. BLAND,

Colonel, Commanding.

P. S.-August 28.-No troops having come down, I shall apply all our energies to the contracting of our limits within reasonable dimensions. It will be difficult to do this before night, having only eight disposable teams and one regiment to move some 10 or 12 miles. Last night the fact of our exposed situation gave me greater uneasiness than I had yet ever experienced.

Respectfully,

P. E. BLAND.