Earth lodges were generally used for large gatherings, such as feasts, councils, or dances. Occasionally there was a depression in the center of the lodge which was used as a fireplace; but it was not over 6 inches deep. Each earth lodge had a ladder, made by cutting a series of deep notches along one side of a log. On a bluff near the Omaha agency I found the remains of several ancient earth lodges, with entrances on the southern sides. Two of these were 75 feet and one was 100 feet in diameter. In the center of the largest there was a hollow about 3 feet deep and nearly 4 feet below the surface outside the lodge. Lodges of Bark or Mats. The Omaha sometimes make bark lodges for summer occupancy, as did the Iowa and Sak. [T]iu′¢ipu jiñ′ga, or low lodges covered with mats, were used by the Omaha in former days. Such lodges are still common among the Winnebago, the Osage, and other tribes. The ground plan of such a lodge forms an ellipse. The height is hardly over 7 feet from the ground. The tent poles are arranged thus: Each pole has one end planted in the ground, the other end being bent down and fastened to the pole immediately opposite; a number of poles thus arranged in pairs formed both wall posts and rafters. [Illustration: Fig. 307.--Ground plan of Osage lodge.] Generally there was one fireplace and one smokehole in such a lodge; but when I visited the Osage in 1883, I entered a low lodge with two fireplaces, each equidistant from its end of the lodge and the entrance, each fireplace having its smokehole. Skin Lodges or Tents. The tent was used when the people were migrating, and also when they were traveling in search of the buffalo. It was also the favorite abode of a household during the winter season, as the earth lodge was generally erected in an exposed situation, selected on account of comfort in the summer. The tent could be pitched in the timber or brush, or down in wooded ravines, where the cold winds never had full sweep. Hence, many Indians abandoned their houses in winter and went into their tents, even when they were of canvas. [Illustration: Fig. 308.--Omaha tent (from a photograph by W. H. Jackson).]