Its top was flat, and large flags of stone formed a rough staircase leading to its roof.

In the centre, a square opening appeared, out of which a tall beam, notched at regular intervals like a primitive ladder, protruded, and down which also the beam disappeared as if extended into the bowels of the earth.

This edifice, half underground, half above the soil, was what to-day is called in New Mexico an _estufa_.[2] This Spanish word has become a technical term, and we shall hereafter use it in the course of the story as well as the designations _tshikia_ and _kaaptsh_ of the Queres Indians.
The estufas were more numerous in a single pueblo formerly than they are now.

Nor are they always sunken.

At the Rito there were at least ten, five of which were circular chambers in the rock of the cliffs.