I immediately, on arriving at Mankato, went to St. Peter, to inform Colonel Sibley of the condition of things in the Indian country. I found him, on the night of August 26th, in camp about six miles out of St. Peter, and put him in possession of everything that had happened to the westward. His mounted men arrived at Fort Ridgely on the 27th of August, and were the first relief that reached that fort after its long siege. Sibley reached the fort on the 28th of August. Intrenchments were thrown up about the fort, cannon properly placed, and a strong guard maintained. All but ninety men of the Cullen Guard, under Captain Anderson, returned home as soon as they found the fort was safe. The garrison was soon increased by the arrival of forty-seven men under Captain Sterritt, and on the 1st of September, Lieut. Col. William R. Marshall of the Seventh Regiment arrived, with a portion of his command. This force could not make a forward movement on account of a lack of ammunition and provisions, which were long delayed. BATTLE OF BIRCH COULIE. On the 31st of August a detail of Captain Grant's company of infantry, seventy men of the Cullen Guard, under Captain Anderson, and some citizens and other soldiers, in all about 150 men, under command of Major Joseph R. Brown, with seventeen teams and teamsters, were sent from Fort Ridgely to the Lower Agency, to feel the enemy, bury the dead, and perform any other service that might arise. They went as far as Little Crow's village, but not finding any signs of Indians, they returned; and on the 1st of September they reached Birch Coulie, and encamped at the head of it. Birch Coulie is a ravine extending from the upper plateau to the river bottom, nearly opposite the ferry where Captain Marsh's company was ambushed.