By John Pint

“We want to show you some petroglyphs located not far from Arandas. We’ve never seen anything like them before.” This email message immediately grabbed my attention because it had been sent by two archaeologists, Rodrigo and Cyntia Esparza.  If the Esparzas considered this rock art extraordinary, I told myself, it must be extraordinary indeed. So, I made an extra effort to try to set up an expedition to Arandas, which is located about 100 kilometers east of Guadalajara, Mexico's second-largest city. Getting there was not exactly easy because the site was at the end of “un camino feo” (literally, an ugly road) and only high-clearance vehicles would be suitable for reaching the place.

A few weeks later, in a Jeep borrowed from a friend of a friend, we found ourselves driving through Arandas. A short while later we arrived at a farm under the care of 79-year-old Don José Flores, who led us toward the edge of a nice-looking lake just below the farmhouse. Two minutes later, we found ourselves surrounded by petroglyphs. These were not on a rock or a canyon wall but spread all over the ground beneath our feet, something I had never seen before. The “ground,” in this case, was a wide expanse of rather smooth, relatively soft volcanic rock from which a thin layer of topsoil had been removed very recently when someone pointed out part of a petroglyph to the owner. To everyone’s surprise, the more dirt they removed, the more petroglyphs were found.

Presa de la Luz, Jalisco, Mexico

Only a few of the engravings suggested something recognizable, like an animal. Some were truly elaborate and bizarre (to modern eyes) and a great many of the glyphs had at least one spiral worked into the design or attached to one end of it.

Don José then said we should take a look at other engravings he had spotted “just 15 minutes away.” Well, the minutes soon turned into hours as we examined more and more rock art on both sides of the lake. In several places we found Pecked Crosses in which the lines of the cross were perfectly oriented with the four cardinal directions, inside two concentric circles or squares made up of a great many tiny pits (“pocitos” the archaelogists called them) which, in some cases total up to 260, exactly the number of days in a Mesoamerican, PreHispanic year. Some of the most famous Pecked Crosses were found long ago at Teotihuacán and were thought to have a calendric purpose. In addition, the four ends of the cross always point north, south, east and west.

It's possible that a small red bean called a patolli may have been moved from pit to pit to keep track of “today” on this simple calendar.

Near the end of the day, a member of our group, Andrew Taylor, spotted one or two of these tiny pits in a little patch of exposed rock and we all drew together to watch him brush away the earth, revealing a very big Pecked Cross—at least one meter in diameter—which Don José had not known about.
How old are the engravings? “They were made about 1100 years ago,” said Cyntia Esparza. “And they are already being destroyed,” added her husband Rodrigo, “by people walking on them.” Indeed, we even found one elaborate representation of a bird (or so we thought) underneath the ashes of a fire someone had recently built exactly there.

El Planchón Principal, the biggest single display of petroglyphs at Presa de la Luz

“This project began in 2012,” Rodrigo Esparza told me. “In our first field-work session, we hired 52 people to clean around the perimeter of the lake. This resulted in welcome work for the local people and exposed a great many petrograbados we hadn't seen before. Once the area had been cleaned up, we got started registering each petroglyph. That year we found about 105 along the lake shore. Many of them were Pecked Crosses.”

“In 2013,” continued Esparza, “we had a second field-work session registering rock art a little farther from the dam, in an area covering about 40 hectares. Here we found many more petroglyphs, which brought the total number up to 600. It was impressive! During this season, we organized another clean-up and a reforestation project in which more than 5,000 trees of various species were planted.”

Susy and I, along with geologist Chris Lloyd, had been invited along to help hunt for new petroglyphs not yet registered. Guided by Don José, we drove to a gently sloping hillside where we found lots of barbed-wire fences and plenty of rock art.

   
The very first example didn't look much like art at all. It was just a hole about ten centimeters wide and 7 deep, nicely rounded. Carving a hole like this, according to archaeologist Joseph Mountjoy, was a very simple way of asking the gods for rain and is probably the most common petrograbado of all. “We found a cave not far from here with hundreds of pocitos like this one,” commented Esparza.

The next most common symbol we saw was the spiral, another prayer for rain. By the end of the day, we had seen a good cross-section of the petroglyphs at Presa de la Luz and I noticed one characteristic many of them had in common: each image has been drawn with a single line. If you challenge someone to draw a mouse or a bird without once lifting their pencil from the paper, they could do it, but this certainly is not the easiest way to draw. The result of such a drawing is something like a maze with one beginning and one end.

Why did these ancient people use this style? Well, it seems to me the “line” is a channel, along which you could move a pebble, as if in a board game or in which you could pour water (or some other liquid). You could even place beetles in the channel, at each extreme and then bet on which will make it all the way to the opposite end. These things are possible only with horizontally situated petroglyphs. Exactly what the engravings at Presa de la Luz mean--and how they were used--is a mystery at the moment.

The rock in which they are sculpted is also mysterious. “This rock is lithic ignimbrite,” Chris Lloyd told me. “This means it flowed here from a volcanic source no more than ten or twelve kilometers away.” Finding the source may represent an interesting challenge for geologists.

Newly discovered petroglyphs at Presa de la Luz