The dwellings were pithouses, partially above and partially below the ground. The underground portion consisted of a shallow pit two or three feet in depth and ten to twenty feet in diameter. Sometimes the earthen walls were plastered with clay, or if the walls had a tendency to cave they were lined with stone slabs. In the floor, forming a large square, four holes were dug and a forked post slightly higher than a man’s head was set upright in each. Four slender logs were placed in the forks of these posts forming a square framework, the main support of the roof. Slender poles were slanted from the edge of the pit to this framework at twelve or fifteen inch intervals, entirely around the room. Other poles were placed across the flat, top portion to complete the skeleton of the roof. To this framework was lashed a solid covering of reeds, brush, bark or coarse grass and the entire roof was covered with a layer of earth several inches thick. A small hatchway was left in the center of the roof. This served as a smoke hole and it was often equipped with a ladder and used as an entrance. The firepit was in the center of the room below the smoke hole. Since the pithouse needed ventilation a tunnel was dug through the south wall and brought to the surface a few feet south of the house. Sometimes this tunnel served merely as a ventilator and crawl entrance but usually the end was enlarged into a room. This second room was always smaller than the main room but it was roofed in much the same manner. In reality a house of this type consisted of the large main room and a smaller antechamber, the two being connected by a tunnel. The location of the antechamber door is uncertain. Probably there was a hatchway in the roof or there may have been a door in one of the side walls. It is certain that the fire in the main room drew fresh air from the antechamber for just in front of the tunnel entrance was placed a large stone slab which served as a deflector. This slab kept the current of fresh air from blowing across the fire and, in the winter, prevented cold air from sweeping across the floor where people were sleeping. The sipapu, a small hole in the floor near the firepit, made its appearance at this time. This feature has continued in use to the present day for some of the modern Pueblo Indians have similar holes in the floors of their kivas. It serves as a symbolic entrance to the Mother Earth and its importance is indicated by the fact that it has persisted for so many centuries.