een in a ruined tower in the vicinity
of Fort Wingate, New Mexico. In the typical roof construction
illustrated the second series is covered with small twigs or brush,
laid in close contact and at right angles to the underlying series, or
parallel with the main beams. Pl. XCVI, illustrating an unroofed adobe
house in Zuni, shows several bundles of this material on an adjoining
roof. This series is in turn covered with a layer of grass and small
brush, again at right angles, which prepares the frame for the reception
of the final earth covering, this latter being the fifth application to
the roof. In the example illustrated the entire earth covering of the
roof was finished in a single application of the material. It has been
seen that at Tusayan a layer of moistened earth is applied, followed by
a thicker layer of the dry soil.

In ancient construction, the method of arranging the material varied
somewhat. In some cases series 3 was very carefully constructed of
straight willow wands laid side by side in contact. This gave a very
neat appearance to the ceiling within the room. Examples were seen in
Canyon de Chelly, at Mummy Cave, and at Hungo Pavie and Pueblo Bonito on
the Chaco.

[Illustration: Plate LXXI. Pescado houses.]

Again examples occur where series 2 is composed of 2-inch poles in
contact and the joints are chinked on the upper side with small stones
to prevent the earth from sifting through. This arrangement was seen in
a small cluster on the canyon bottom on the de Chelly.

The small size of available roofing rafters has at Tusayan brought about
a construction of clumsy piers of masonry in a few of the larger rooms,
which support the ends of two sets of main girders, and these in turn
carry series 1, or the main ceiling beams of the roof. The girders are
generally double, an arrangement that has been often employed in ancient
times, as many examples occur among the ruins. The purpose of such
arrangement may have been to admit of the abutment of the ends of series
1, when the members of the latter were laid in contact. In the absence
of squared beams, which seem never to have been used in the old work,
this abutment could only be securely accomplished by the use of double
girders, as suggested in the following diagram, Fig. 38.

[Illustration: Fig. 38. Showing abutment of smaller roof beams over
round girders.]

The final roof covering, composed of clay, is usually laid on very
carefully and fir