We turned onto a washboard gravel road and 12 minutes later came to a small parking area, 49 road miles inside the base’s main gate at the edge of Ridgecrest. On this November day the thermometer read 43 degrees, but the air was still and the sun felt warm. We shouldered our lunches and camera gear and walked out along a path made of interlocking plastic tiles laid down in recent years so that Shoshone tribal elders could reach the site without having to struggle in the soft sand. Almost immediately we were in what is known as Little Petroglyph Canyon.

Everywhere we looked, for a mile or so down canyon, there were images pecked or scratched into the rock faces: stylized human figures in a variety of headgear, stick figures with bows and arrows, dogs or coyotes, bear paws with extra digits, all manner of abstract geometric patterns, zigzags and circles and dots, and hundreds upon hundreds of what looked like bighorn sheep, some small, some larger than life size.

Image Credit... Bill Becher for The New York Times The New York Times

Theories abound as to what the images might mean  all but the most recent, that is  or why they were put there. Some archaeologists believe that the images are evidence of simple hunting rituals. Mr. Whitley sees in them nothing less than the origins of human creativity and religion.

He theorizes, based on his research, that the petroglyphs are the work of generations of shamans, or medicine men, who traveled here (from all over what is now the southwestern United States) to fast and smoke native tobacco, to hallucinate or have visions, and to render their hallucinations on the rock. Perhaps the goal was to make rain. Perhaps it was to impress upon their followers a sense of the supernatural. Either way, where some might see a dearth of material wealth and technology, Mr. Whitley sees evidence of cognitive sophistication.

“We think of intelligence as expressed in iPods and the latest iPhone,” he said. But technology is often a poor substitute for knowledge: “Drop any of us in Death Valley and unless we had an RV fully stocked with all sorts of supplies we’d be dead in a week,” he said. The people who came before us, on the other hand, were adapted to this environment, so they could survive with nothing but what they could find or make, in a way that, he said, “runs counter to our technological materialistic view, is probably more admirable, and certainly more sustainable.”

For a time, after 9/11, civilian visits to the petroglyphs were suspended. “There’s always a risk when you let civilians into a secured area,” Ms. Shoaf said. But she said she felt the place was too precious for the public not to have access. So she rewrote the protocol to show the commanding officer how it might be possible to allow tours and still protect the base’s security. He agreed. More than 1,100 civilians visit the site every year, either on tours available to the public or as part of private tours with command-approved escorts arranged through Ms. Shoaf’s office.