HEADQUARTERS NORTHWESTERN INDIAN EXPEDITION,
Camp Numbers 24, Fort Rice, Dak. Ter., July 17, 1864.

ASSISTANT ADJUTANT-GENERAL,

Department of the Northwest:

SIR: To-morrow I shall take up my line of march westward. A large body of emigrant wagons with ox teams and with women and children have followed the Minnesota troops to this point. I wish they were away from here. I can't send them back. I can't leave them here, for I can't feed them, and they even have come to me for permission to purchase rations, which I cannot do, for there is danger of my not getting enough rations up here to supply the post on account of low water, and the river is falling very rapidly. Therefore I am forced to take them with me. Their ox teams cannot keep up with my mules. I shall therefore detail 400 men to march with them. This will leave me about 2,000 men for fighting; enough if they were worth anything. This force may appear small comparing it with my returns (near 4,000), but after a long march over the prairie many men not used to the life get sick, and I have had to leave them here and at posts on the river, and also the force to build this post and guard cattle and horses. My boats have left some days ago, some up and some down, for supplies, but the appearance of the river alarms me. Sand-bars are showing themselves in all directions. If the boats I sent below can't get up with supplies I will be obliged to hire teams to haul the supplies here from Farm Island (172 miles) at a great expense. I wish I could have had my own way in the matter of transportation. I know I could have done better than the chief of transportation at Saint Louis, for I am better acquainted with the river. I find quite a quantity of my stores are damaged, particularly the flour, which, having been kept so long in the hold of the steamers and in sacks, has become heated. In exploring around the country quite a large amount of coal has been found. At one place, about three miles from here, a large mine has been found that has every indication of being of great consequence; about one-half mile of a ledge, about sixteen inches wide, cropping out the side of a hill, has been found. I have not time to dig and find the extent, but do not doubt it is of sufficient size to be of great importance, at least to supply fuel to the post, if not for other purposes. If it turns out to be what I have every reason to believe it will, it will be very valuable. I am told it is to be found in many places. I have included it in the military reservation.

With much respect, your obedient servant,

ALF. SULLY,

Brigadier-General.

HDQRS. MILITARY DIVISION OF WEST MISSISSIPPI,
New Orleans, La., July 18, 1864.

Rear-Admiral D. G. FARRAGUT,

Commanding W. G. B. Squadron, off Mobile, Ala.:

ADMIRAL: I have the honor to state that in consequence of the changes resulting from the transfer of troops to the Army of the Potomac there will be more delay in collecting the force to be sent to you than I expected when I saw you. They will be ready, I think, before repairs to the monitors now here are completed. I design sending about 4,000 men. I send over to-day Colonel Myer and Captain McAl-