Monday, January 10, 2011

The Ruins at Casa Grande

This is not really a performing arts event, or if it is, it is one that occurred at least six hundred years ago. The Hohokam Indians of southern Arizona had a prosperous civilization between Phoenix and Tucson between A.D. 1200 and 1450, at which time they disappeared. I took an archaeological tour of the remains of their civilization, sponsored by The Archaeological Conservancy, a nonprofit organization that acquires and preserves endangered archeological sites across America ( The guide for our group of eight was Allen Dart, M.A., a professional archaeologist and Executive Director of the Old Pueblo Archaeology Center in Tucson (

We began with the ruins of the “Great House” at Casa Grande, AZ. “Casa Grande” means “great house.” The town is named after the ruins. The great house was four-story public building, probably a meeting place and a center of government, built around 1300. It is made of adobe-like bricks, which essentially “melt” in the rains, so it is badly decayed. It has survived seven centuries mainly because the bricks are cut from the rock-hard caliche soil of southern Arizona. That is soil saturated with calcium compounds, the bane of gardeners today. There isn’t much rain in southern Arizona (only about 12 inches a year today – no telling what it was 700 years ago), so the building has stood up surprisingly well, considering the technology. The Park Service put a protective roof over the ruins in 1932, to slow down its rate of decay. Since the 1800’s, the Park Service has also added several structural supports to keep the remaining walls from collapsing.

The great house is interesting architecturally. Its exterior walls are not straight on the vertical dimension, but curved inward toward the top, giving the whole structure a graceful look, like a piece of pottery. This design supposedly added greater strength to the overall structure when the wooden roof beams tied the top of the walls together. At least that is what our archaeologist said, but that doesn’t fit with my intuition of how the forces would work. In any case, it would have been a beautiful building when new in 1300 or so.

The interior rooms are small. Even the large ones are only about 10 x 14, although ceilings are 20 feet high. Interior doorways are so low that you would have to be about five feet tall to use them, or bow to pass through. They are so narrow that you have to turn sideways to use most of them. I don’t know the average height of the Hohokams, but I suspect that the shape of the openings in the structure are due to a combination of temperature management and structural necessity (there are no arches or non-adobe lintels).

The rooms are now derelict, full of bird droppings and rodent holes, with the walls sporting carved graffiti from the 1800’s. The graffiti is itself interesting sometimes. Travelers apparently stopped here for shelter in the 19th century. “Carlos 1889,” carved his name about 12 feet up a wall, so there might have been a wooden floor part way up at one time, or else Carlos stood on some wooden structure, now lost, or else Carlos was a giant. Thanks, Carlos. You could have left us a little more detail.

There is some speculation that the great house was used for astronomical observations. There are a couple of interesting holes in the south fa├žade that archaeologists say provide a line of sight with the sun at summer and winter solstices. That seems plausible, but I doubt that the entire compound would have been devoted to that single purpose.

Around the great house, on a flat site about four acres, there are low adobe walls, remnants of outbuildings, which are thought to have been used for storage of grains, or possibly as animal pens. There is no archeological evidence that anyone ever lived at the great house or its outbuildings (i.e., no fireplaces found), so it was probably strictly a government compound and a general meeting place. If the outbuildings were indeed used for food storage, that implies that they had a system of taxation, and if so, you wonder what public services the taxes supported. Probably religious ceremonies, but who knows. I guess we still have the same question today about how our taxes are used!

The Hohokams had no written language so we don’t know much about them, or even why they disappeared. One prominent theory, endorsed by archaeologist Dart, is that a long period of drought dropped the water level of the nearby Gila River so low that it could not fill the irrigation canals any more. So the crops died and the civilization collapsed. Another theory is that there was some sort of a political revolution when the rulers became tyrannical (as rulers are wont to do), leading to destruction of the social order. The revolution theory and the drought theory are not incompatible. My favorite speculation is that the Hohokam people did not disappear, but just dispersed. Their descendants are, by Native American oral tradition, the Tohono O’odham Indians around Tucson today.

One more interesting feature of the ruins site is the ancient ball court near the great house. The court is much smaller than I had imagined, only an oval depression in the soil about fifty yards long. There is some archaeological evidence that such structures were used for a kind of team ballgame, and there is some documentary evidence associated with similar sites in Central America. The speculation is that the Hohokam would have used a stone ball wrapped in leather, or possibly a ball made of a hard, plastic-like substance composed of hardened tree resin and an unidentified waxy material. What the game was like or how it was played, or why, is unknown. Was it just for fun? Was there betting? Or were they not really “games” at all, but deadly serious theater symbolically representing cosmic forces, or even contests among competing tribes? Archaeologist Dart suggested that the ballgames were discontinued in the 1300’s, so the culture must have evolved. The so-called ball courts could have been used also for theater or for speeches, as the acoustics are very good around the rim, for someone speaking in the center, as Mr. Dart demonstrated. Normally, the public is not allowed into the environmentally and archaeologically sensitive area where the ball court is found, but we were special because we had a card-carrying archaeologist with us. (The whole group was closely shadowed by a Park Service ranger the whole time anyway).

After a picnic lunch, the group drove off to visit several other archaeological sites in the area, including the “Grewe” site to the north, where the Hohokam first settled. For reasons unknown, the center of their civilization gradually migrated south to the Casa Grande site. The Grewe site is largely unexcavated, so there is nothing to see but some large, fenced-off, open fields of brush and cactus, and a large Wal-Mart. Dart told us that ancient artifacts were discovered when they dug up the area for the construction of the Wal-Mart, and to their credit, the Wal-Mart people stopped, and changed the whole plan of the store and its parking, to leave the ancient underground artifacts as little disturbed as possible.

We visited a few other sites in the area that only an archaeologist would be able to recognize as ancient ruins, and saw some building foundations and some depressions in the ground that were clearly ball courts, if you knew what you were looking at. It was interesting to realize that all around these small towns like Florence and Coolidge were ancient Indian ruins. You would have to have a trained eye to see it though.

Finally we visited a site called the Poston Butte Ruin, which I think was actually private property for which Dart had been granted access. There we walked over a featureless desert of rolling hills. Except Dart told us they were not “natural” rolling hills but ancient Indian garbage mounds. Once we knew what to look for, it was easy to see five and six-hundred year old pottery shards everywhere, some of them quite beautiful. As the rains fall, the dirt of the trash piles gradually erodes, exposing the piles of broken pots and other artifacts. I found a six-hundred year-old stone scraper tool. It was a thrill to hold it in my hand and wonder about the person who had made it so many centuries ago. Mr. Dart, with his special “archaeologist’s eyes” found a tiny bone carving of a coyote, only an inch long. I could have looked right at that fragment a dozen times and never seen it, but after it was identified, we could see it was a beautiful and detailed work of art. I don’t see how such a carving could have been made with stone-age technology, but there it was.

Naturally, we put all artifacts back on the ground exactly where we had found them. It is pointless to collect such artifacts, and illegal at most sites (i.e, in National Parks), and an anti-scientific vandalism, and a cultural desecration. As we were told. Repeatedly. See for the full speech/sermon.

After a long day of hiking, I got accustomed to walking with my eyes on the ground, alert to the many artifacts that are in this area. I started to develop “archaeologist’s eyes,” maybe a little, and at least, got a good feel for what archaeologists do and what ancient Indian archaeology is like in this part of Arizona.

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