The most striking feature of this structure [ruin] is the round room, which occurs about the middle of the ruin and inside of a large rectangular apartment.... Its walls are not high and not entirely regular, and the inside is curiously fashioned with offsets and box-like projections. It is plastered smoothly and bears considerable evidence of having been used, although I observed no traces of tire. The entrance to this chamber is rather extraordinary, and further attests the peculiar importance attached to it by the builders and their evident desire to secure it from all possibility of intrusion. A walled and covered passageway of solid masonry, 10 feet of which is still intact, leads from an outer chamber through the small intervening apartments into the circular one. It is possible that this originally extended to the outer wall and was entered from the outside. If so, the person desiring to visit the estufa [kiva] would have to enter an aperture about 22 inches high by 30 wide and crawl in the most abject manner possible through a tube-like passageway nearly 20 feet in length. My first impression was that this peculiarly constructed doorway was a precaution against enemies and that it was probably the only means of entrance to the interior of the house, but I am now inclined to think this hardly probable, and conclude that it was rather designed to render a sacred chamber as free as possible from profane intrusion.[23]
In this example the tunnel was much larger than usual and the vertical shaft, if there were one, has been so much broken down that it is no longer distinguishable. Nordenskiöld mentions a considerable number of kivas with this attachment, and one which is described and figured is said to be a type of all the kivas in that region, but an inspection of his ground plans shows more kivas without this feature than with it. In his description of a small ruin in Cliff canyon he speaks of—
... a circular room still in a fair state of preservation. The wall that lies nearest the precipice is for the most part in ruins; the rest of the room is well preserved. After about half a meter of dust and rubbish had been removed, we were able to ascertain that the walls formed a cylinder 4.3 meters in diameter. The thickness of the wall is throughout considerable, and varies, the spaces between the points where the cylinder touches the walls of adjoining rooms[24] having been filled up with masonry. The height of the room is 2 meters. The roof has long since fallen in, and only one or two beams are left among the rubbish. To a height of 1.2 meters from the floor the wall is perfectly even and has the form of a cylinder, or rather of a truncate cone, as it leans slightly inward. The upper portion, on the other hand, is divided by six deep niches into the same number of pillars. The floor is of clay, hard, and perfectly even. Near the center is a round depression or hole, five-tenths of a meter deep and eight-tenths of a meter in diameter. This hole was entirely full of white ashes. It was undoubtedly the hearth. Between the hearth and the outer wall stands a narrow, curved wall, eight-tenths of a meter high. Behind this wall, in the same plane as the floor, a rectangular opening, 1 meter high and six-tenths of a meter broad, has been constructed in the outer wall. This opening forms the mouth of a narrow passage or tunnel of rectangular shape, which runs 1.8 meters in a horizontal direction and then goes straight upward, out into the open air. The tunnel lies under one of the six niches, which is somewhat deeper than the others. The walls are built of carefully hewn blocks of sandstone, the inner surface being perfectly smooth and lined with a thin, yellowish plaster. On closer examination of this plaster it is found to consist of several thin layers, each of them black with soot. The plaster has evidently been repeatedly restored as the walls became blackened with smoke. A few smaller niches and holes in the walls, irregularly scattered here and there, have presumably served as places of deposit for different articles; a bundle of pieces of hide, tied with a string, was found in one of them. The lower part of the wall, to a height of four-tenths of a meter, is painted dark red around the whole room. This red paint projects upward in triangular points, arranged in threes, and above them is a row of small round dots of red.... Circular rooms, built and arranged on exactly the same plan as that described above, reappear with exceedingly slight variations in size and structure in every cliff dwelling except the very smallest ones.... The number of estufas [kivas] varies in proportion to the size of the buildings and the number of rooms, ... [The ruin described contained two kivas.] ... The description of the first estufa applies in every respect to the second, with the single exception that the whole wall is coated with yellow plaster without any red painting. The wall between the hearth and the singular passage or tunnel described above is replaced by a large slab of stone set on end. It is difficult to say for what purpose this tunnel has been constructed and the slab of stone or the wall erected in front of it. As I have mentioned above, this arrangement is found in all the estufas.[25]
The general similarity between the kivas of De Chelly and those of the Mesa Verde region will be apparent from the above description. It should be added that in the section which accompanies it the roof of the tunnel appears to be supported by a series of small cross sticks, although no information on this point is afforded by the test. The examples which occur in De Chelly are apparently much ruder and more primitive than those of the Mancos, and only one of them approaches the latter in finish and elaboration.
In another place[26] Nordenskiöld mentions an example in which two small sticks were incorporated in the masonry of the upper part of the tunnel in a diagonal position. From this he rejects Holmes' explanation that the passageway was used as an entrance to the kiva, nor does he find the chimney hypothesis satisfactory. He states, further, that the use of this feature as a ventilator seems highly improbable. In one place he found the curtain or screen constructed not of masonry, but—
... of thick stakes, driven into the ground close to each other, and fastened together at the top with osiers. On the side nearest to the hearth this wooden screen was covered with a thick layer of mortar, probably to protect the timber from the heat.[27]
As stated elsewhere, the first hypothesis formed in the field as to the purpose of these chimney-like structures was that they were abortive chimneys, but this was found untenable. The next hypothesis, formed also in the field, was that they were ceremonial in origin and use, but why they should connect with the open air is not clear. If we could assume that they were ventilators, the problem would be solved, but it is a far cry from pueblo architecture to ventilation; a stride, as it were, over many centuries. Ventilation according to this method—the introduction of fresh air on a low level, striking on a screen a little distance from the inlet and being thereby evenly distributed over the whole chamber—is a development in house architecture reached only by our own civilization within the last few decades.
If the shaft and tunnel were in place, however, the screen might follow as a matter of necessity. Entrance to the kivas is always through the roof, a ceremonial requirement quite as rigidly adhered to today among the Pueblos as it was formerly among their ancestors. The same opening which gives access also provides an exit to the smoke from the fire, which is invariably placed in the center of the kiva below it. This fire is a ceremonial rather than a necessary feature, for in the coldest weather the presence of a dozen men in a small chamber, air-tight except for a small opening in the roof, very soon raises the temperature to an uncomfortable degree, and the air becomes so fetid that a white man, not accustomed to it, is nauseated in half an hour or less. Such are the conditions in the modern kivas of Tusayan. In the smaller structures of De Chelly they must have been worse. The fire is, therefore, made very small and always of very dry wood, so as to diminish as far as possible the output of smoke. Frank H. Cushing states that in certain ceremonials which occur in the kivas it is considered very necessary that the fire should burn brightly and that the flame should rise straight from it. If this requirement prevailed in De Chelly, a screen of some sort would surely follow the construction of a shaft and tunnel.
More or less smoke is generally present in the kivas when a fire is burning, notwithstanding the care taken to prevent it. That a similar condition prevailed in the kivas of De Chelly is shown by the smoke-blackened plaster of the interiors. In some cases there was a room over the kivas which must have increased the difficulty very much. There can be little doubt that the chimney-like structures were not chimneys, and no doubt at all that they did provide an efficient means of ventilation, no matter what the intention of the builders may have been. When we know more of the ceremonials of the Pueblo Indians, and when extensive excavations have developed the various types and varieties of these structures in the ruins, we may be able to determine their object and use.