Pl. XLV, an illustration of a Mormon mill building at Moen-kopi, already referred to in the description of that village, is introduced for the purpose of comparing the methods adopted by the natives and by the whites in the treatment of the same class of material. Perhaps the most noteworthy contrast is seen in the sills and lintels of the openings. ROOFS AND FLOORS. In the pueblo system of building, roof and floor is one; for all the floors, except such as are formed immediately on the surface of the ground, are at the same time the roofs and ceilings of lower rooms. The pueblo plan of to-day readily admits of additions at any time and almost at any point of the basal construction. The addition of rooms above converts a roof into the floor of the new room, so that there can be no distinction in method of construction between floors and roofs, except the floors are occasionally covered with a complete paving of thin stone slabs, a device that in external roofs is confined to the copings that cap the walls and enframe openings. [Illustration: Plate LXX. Court view of Pescado, showing corrals.] [Illustration: Fig. 37. Diagram of Zuñi roof construction.] The methods of roofing their houses practiced by the pueblo builders varied but little, and followed the general order of construction that has been outlined in describing Tusayan house building. The diagram, shown in Fig. 37, an isometric projection illustrating roof construction, is taken from a Zuñi example, the building of which was observed by the writer. The roof is built by first a series of principal beams or rafters. These are usually straight, round poles of 6 or 8 inches in diameter, with all bark and projecting knots removed. Squared beams are of very rare occurrence; the only ones seen were those of the Tusayan kivas, of Spanish manufacture. In recently constructed houses the principal beams are often of large size and are very neatly squared off at the ends. Similar square ended beams of large size are met with in the ancient work of the Chaco pueblos, but there the enormous labor involved in producing the result with only the aid of stone implements is in keeping with the highly finished character of the masonry and the general massiveness of the construction. The same treatment was adopted in Kin-tiel, as may be seen in Pl. XCV, which illustrates a beam resting upon a ledge or offset of the inner walls. The recent introduction of improved mechanical aids has exerted a strong influence on the character of the construction in greatly facilitating execution. The use of the American ax made it a much easier task to cut large timbers, and the introduction of the “burro” and ox greatly facilitated their transportation. In the case of the modern pueblos, such as Zuñi, the dwelling rooms that were built by families so poor as not to have these aids would to some extent indicate the fact by their more primitive