Chaco Canyon National Monument was established by presidential
proclamation in 1907, owing largely to the efforts of Edgar L. Hewett,
Director of the Museum of New Mexico and the School of American
Research, whose first of many expeditions into the canyon was in 1902.
Pueblo Bonito, "the pretty village," has been known by that name since
at least as far back as 1840, and was probably named by Spanish or
Mexican soldiers or traders.
Excavation of Pueblo Bonito was begun in 1896 by Richard Wetherill who
homesteaded in the canyon, and by George H. Pepper of the American
Museum of Natural History. The work was financed by two wealthy young
brothers from New York, Frederick and Talbot Hyde, who formed the Hyde
Exploring Expedition for the purpose. In four seasons 190 rooms were
cleaned out. Research was resumed by a joint National Geographic
Society--U.S. National Museum expedition in 1921 under the direction of
Neil M. Judd, who in seven summers completed the excavation of 600 or
more rooms and 33 kivas, and made extensive tests in the large trash
mound, and in the plaza.
The Bonito Trail is about one-third of a mile long.[1] Along it you will
find numbered markers corresponding to numbered paragraphs in this
booklet. Please keep off all ruin walls.
[1]_For metric conversion see table in back._
1
Pueblo Bonito, probably the largest single prehistoric Indian building
in the Southwest at the time it was constructed, represents the highest
development of Anasazi architecture. Most of the construction was
between the years A.D. 1030 and 1079. The bulk of the wall's thickness
was made up of rough, unshaped random stones laid in mud mortar. Then
the walls were veneered, inside and out, with the carefully fitted stone
you see here. The stone used for the facing, a hard, dense sandstone,
was quarried from a narrow band of rock at the top of the cliff behind
the pueblo. So much of this stone was used to build the great houses of
the canyon that most of it has been removed for a mile east and west of
Pueblo Bonito, but in other places the signs of ancient quarrying are
still evident.
[Illustration: _West end of Pueblo Bonito during excavation by
Wetherill and Pepper in the 1890's_]
The small, rectangular openings in this wall were vents for air and
light in the lower rooms. The round holes are sockets for vigas, ceiling
beams.
2
The large, broken stones here and to your left are what remain of
Threatening Rock, a large vertical slab of native rock which once stood
separated from the cliff by a wide crack. The people of Pueblo Bonito
felt the threat of its fall, for using posts, mud, and stone masonry,
they attempted to shore up the rock, or to prevent erosion of its base.
Here you can see a remnant of that early attempt. The Navajos, who were
not here until long after the last of the Anasazi departed, call Pueblo
Bonito "the place where the cliff is propped up", and they relate a tale
about their predecessors pouring baskets of turquoise and white shell
behind the rock as an offering to the spirits to prevent its fall. When
the huge slab finally came down in January 1941, no turquoise was found,
but it was discovered that the Anasazi had placed prayer sticks behind
the rock. These are peeled and carved willow wands, painted and
decorated with feathers, which are still used by Pueblo people somewhat
in the way altar candles are used.
[Illustration: _Prehistoric masonry at base of Threatening Rock
before it fell--photo 1896_]
[Illustration: Feathered wand.]
3
The rock around you is sandstone of the Cliff House formation, a member
of the Mesaverde group of sedimentary rocks laid down in Cretaceous
times--70 to 80 million years ago--near the edge of a shallow sea. When
the shoreline retreated and the waters became shallower, and fresh or
brackish, the sediments were in the form of carbonaceous shale and coal
which are exposed across the canyon. The Indians made no use of the coal
as fuel, but jet and shale from that formation were made into figurines,
beads, and pendants, and decomposed shales were used for pottery clay
and for mortar.
[Illustration: Clay figurine.]
4
Here is an overall view of Pueblo Bonito and the more than three acres
it covers. The panels in front of you describe the construction
sequences. An existing southeast-facing pueblo was used as the nucleus
for the grander multi-storied Pueblo Bonito. The symmetry of the ground
plan indicates that a well-conceived basic plan was adhered to
throughout three generations of remodeling and enlarging.
We don't know the exact number of rooms the pueblo contained because
many of the upper walls had fallen during the centuries it stood empty
and abandoned, but sections of the rear wall were known to be five
stories high, and some estimates run to 800 rooms. However, many of the
rooms in the older section were trash-filled to serve as footings for
the rooms above, and other rooms were destroyed to clear space for
kivas, and it is probable that no more than 600 rooms were usable at any
one time. The excavator, Judd, estimated a population of 1,000.
From here, too, you can see the pueblo in relation to its canyon setting
and to some of its sister communities. The deep arroyo in the middle of
the floodplain was probably a shallow streambed bordered by sedges,
willows, and cottonwoods. Otherwise the environment was not much
different from what we know today. Garden plots, irrigated both from the
arroyo and by runoff water from the cliffs, covered much of the canyon
bottom.
A relatively smaller population of Anasazi had inhabited the canyon for
at least 500 years when, with the building of Pueblo Bonito and other
large communal houses, the population was greatly swelled. The increased
demands for wood and water, more intensive cultivation, and the heavy
foot traffic on friable soil undoubtedly placed a strain on the
environment, but the deterioration of resources alone doesn't explain
the total abandonment of the area at about A.D. 1300. It is likely that
there were political, or other social factors involved whose traces are
hard to find in the archeological remains.
[Illustration: Map of Chaco Canyon.]
5
This broken section of wall shows its construction of a core of rough
stone faced with smaller, selected stones, each having at least three
plane surfaces. Note that the wall is thick at the bottom where the
entire weight was carried, but is narrower at the top where less
strength was needed. The tapering is evidence of prior planning--the
builders knew when they started that they were going to build four to
five stories--but the wall was not erected as a single operation. As the
height for each story was reached, beams were built into the wall, and
the ceiling was covered to provide a platform from which to work while
raising the walls another stage.
6
You are standing near the ceiling level of the ground floor rooms. Rock
debris and silting from the canyon wall has buried the lower part of the
house. By referring to the ground plan at the front of the booklet you
can see that this section of the wall is a "curtain wall" with a narrow,
triangular space behind it. Visible in the masonry are the butts of
small poles used as tie rods that bridge the opening behind the wall.
The space was not a room, but was filled to lend strength to the
juncture of the older western section and a new arc of outside wall
running east. At the top of the wall to your right you can see timbers
built into masonry like reinforcing rods.
[Illustration: Construction detail.]
At the foot of the cliff behind the ruin are the remains of a kiva and a
one-room house built against the rock. There is an interesting
petroglyph cut into the sandstone.
7
You may walk into this small ground floor storeroom to inspect the
original ceiling. The doorway was once plugged with masonry, but it was
opened by an early explorer. This section of the pueblo is part of the
first construction of Pueblo Bonito behind the older pueblo of the A.D.
900's. Tree-ring dates from the Ponderosa pine vigas indicate that the
room was built in A.D. 1038. Peeled willow sticks were laid across the
beams and covered with juniper bark, and finally about six inches of
packed soil to make a floor for the room above. The room to the left has
not been excavated.
The next doorway you pass on your way to Station 8 is now closed with a
modern gate. The room behind it was used for a storeroom by Richard
Wetherill whose first camp was pitched outside the wall of the pueblo in
this vicinity. When Pueblo Bonito was built there were 18 doorways in
the rear wall, but all were plugged up by the Indians at some later date
so that the only entry into the house was at the south wall of the
plaza.
8
The rooms surrounding you are part of the old, southeast-facing pueblo,
built between 919 and about 936, over and around which the grander
Pueblo Bonito was built 100 years later. Note the cruder masonry and
thinner walls. The vertical poles incorporated into the wall in front of
you represent an earlier method of construction. Often the poles
supported a matting or wattle of small branches which served as lath to
hold a thin wall of mud plaster. Later the people used small posts as a
frame for stacking hand-molded adobe bricks or stones, and still later
began to lay ashlar courses in which the strength was gained by lapping
stones across the joints between stones in the course below. When Pueblo
Bonito was built, the eastern end of the old pueblo was leveled to make
way for new rooms, and some rooms at the southwest end were torn out
when kivas were put in.
[Illustration: _Hyde Expedition camped behind Pueblo Bonito,
1890's_]
Many of the old rooms were filled with trash and it is possible that the
smaller pueblo was not occupied when the new builders started to work on
the later structure. Eight or more of the rooms (including the one you
are standing in) had been used as burial chambers for more than 90
individuals.
The burials that have been found in Chaco have been of the people who
preceded the builders of Bonito and the other great pueblos, or of
contemporaries of theirs from the many smaller pueblos in the canyon, or
of members of a small group that moved into the canyon from the north
after Pueblo Bonito was largely, if not entirely, abandoned. So far
archeologists have not discovered how, or where, the considerable
population that lived in Pueblo Bonito, Chetro Ketl and other large
houses disposed of their dead.
The modern roofs in this area protect remains of original ceilings.
9
This open area is the plaza or courtyard. It served much the same
function as a town square where ceremonial dances and other group
activities took place. Also, when weather permitted, much of the daily
domestic work was done here--shelling corn, twisting cordage, scraping
hides, firing pottery, and fashioning tools of stone, bone and wood.
[Illustration: Shelling corn.]
The plaza was divided by a single row of rooms into two courts. Many
grinding stones were found in these rooms which served as one of two
community centers for mealing corn into flour. Corn was ground on a
large troughed stone, the metate (meh-TAH-tay), with a smaller,
loaf-shaped stone, the mano. The metates were arranged in a line of bins
where several women could work together. Another milling center was in
four adjacent rooms in the east wing.
10
The round underground room, a bit over 45 feet in diameter at the floor,
is a great kiva which served as a religious center. Its roof, supported
by four rubble-filled masonry columns, was 9 feet 7 inches above the
floor. Thirty-four niches around the wall above the upper bench may once
have held offerings of jewelry and other valued materials, but were open
and empty at the time of excavation. The chamber was entered at the
north end by a series of stone steps. You may enter and examine in
detail a great kiva across the canyon at Casa Rinconada.
Another great kiva in the west court, and the division of the plaza,
suggests to some students that the people were divided into two groups,
each group responsible for certain ceremonies at different times of the
year--summer people and winter people--as is true of many of the Rio
Grande pueblos today.
[Illustration: _National Geographic painting by Peter V. Bianchi,
February 1964_]
11
The ordinary kivas let down into this raised terrace served smaller
groups than the great kiva. In today's Pueblo villages kivas are used as
meeting places by both male and female members of curing societies, as
workshops for making ritual equipment, for dance rehearsal, and as
sleeping places for boys while they are receiving religious instruction.
Kivas were more numerous than great kivas--37 have been identified in
Pueblo Bonito--though not all were usable at one time. The kiva on the
left was razed. All the timbers were removed and the open pit was used
as a refuse dump by people in nearby rooms.
An architectural trait peculiar to Chacoan kivas is the low bench with
from four to ten pilasters made of juniper logs buried in the wall and
extending horizontally onto the bench. The pilasters supported the butts
of log stringers which encircled the kiva. The stringers held the weight
of another, but smaller, circle of stringers, and that circle still
another, until 12 to 14 layers of poles in ever-decreasing circles made
a dome-like ceiling of cribbing. A nearly intact roof in a nearby kiva
was found to have used 350 timbers in its construction.
Close to the wall the ceiling was only about three feet above the floor,
but at the center of the room there was an eight to ten foot clearance.
The space between the outside of the roof-dome and the wall of the kiva
was filled with earth and rubble to level off a flat court even with the
level you are standing on. When these kivas were all in use their
presence was indicated only by ladders protruding from rectangular
openings which served both as entryways and smoke holes.
[Illustration: sub-floor vent]
The trench in the floor, once covered with slabs of stone, was an air
duct. Rising heat from the fire in the round pit pulled fresh air
through the duct and down a vertical shaft just outside the kiva wall to
provide ventilation.
The smaller kiva on your right, as you proceed along the trail, is
unusual in having four tall masonry pilasters. Rather than a cribbed
roof, it probably had a flat roof of horizontal timbers to give it an
even seven-foot clearance over the entire space.
12
These ground floor rooms were used for storage and were reached from the
living rooms above them by means of ladders through open hatchways in
the ceiling.
Doorways were closed by leaning large, flat slabs of ground sandstone
against sloping collars of masonry in the jambs, or by suspending
matting from small sticks in the lintel.
13
The fire-reddened walls in this room resulted from a fire that destroyed
the ceiling. The unburned area near the floor shows that the fire
occurred after abandonment of the rooms. The earthen floors of the rooms
above had leaked through and piled up against these walls. Tree-ring
dates from charred beams fallen to the floor indicate construction at
about A.D. 1100--one of the last additions to be built. The room had
been left empty except for three scrapers made from deer bone. Each was
beautifully inlaid with turquoise, jet and shell.
[Illustration: Scrapers made from deer bone.]
Note the diagonal doorway in the southeast corner of the room above.
14
The three doorways in this room have been successively modified by
adding new sills, lintels, and secondary jambs, sloped to accommodate
door slabs.
The doors may seem small but they were not made for ease of passage, but
rather for reduced heat-loss and to make them easier to close off. In
fact, the doors of the great Chacoan pueblos were unusually large for
Anasazi houses. Typical doorways for the period were narrower and with
high sills.
The mud plaster on the south wall is original.
15
The doorway in the east wall was plugged with masonry. Such sealed-off
doors were common and probably for a variety of reasons as the use of
rooms changed and apartments were rearranged. Sometimes grain-storage
rooms were temporarily closed with quickly-laid, crude masonry and
mortar to render them rodent-proof.
[Illustration: _Series of doorways_ [photo by Hal Malde]]
Almost ten feet below this floor is the floor of a kiva which was part
of an earlier version of Bonito's town plan. It was filled and buried by
this later construction.
16
The T-shaped doorway, though not common, is found from Colorado and Utah
south into the mountains of northern Mexico. We can only speculate about
its purpose. Of the 32 T-doors remaining in Pueblo Bonito, most are
exterior doors facing kiva courts.
17
This well-preserved ceiling is the original one. The fresh-looking sawed
ends and notches in the beams is where sections were removed for
tree-ring dating. The small round holes, less destructive of the timber,
are made with a hollow auger bit which removed a core--the preferred
method of taking samples. Seven dates were obtained from the cores and
sections in this room. Three of them were cutting dates, indicating the
last year of the growth of the trees: A.D. 1077, 1078, and 1079. The
construction date was probably 1079 or 1080.
Though this section of the pueblo was three stories high, some of the
ground floor rooms were used as living quarters equipped with firepits.
Relatively few firepits were found in the ruin, most of them in one
story sections, in the open on the edges of the plaza, or next to an
outer wall in a kiva courtyard, but there was evidence in the fill of
the rooms that others had existed on the upper floors and on the
terraced roofs.
18
Above and to the left of the rooms you have just left is another corner
window. On the morning of the winter solstice in December the rays of
the rising sun shine through this window and strike the opposite corner
of the room behind it, a fact that is probably more than coincidental.
We know that in the 11th century Indians in Mexico were making solar and
lunar observations and calculations that were in some respects more
sophisticated than were possible in most of Europe.
The long low ridge in front of the pueblo was the trash dump. It was
built up of ashes from the firepits, floor sweepings, construction
debris, bones, food refuse, human waste, scraps from craftwork, broken
pottery--everything that was no longer of any use. With only a little
imagination one can picture the mound with a band of small, naked
children playing "king of the hill", and with foraging turkeys, and dogs
burying or digging up bones.
[Illustration: _Four story wall_ [photo by Hal Malde]]