Lahren and Papworth will call the shots; the rest of the all-volunteer team, including a geologist, an anthropologist, and some students and friends of Lahren's, will do the grunt work, cleaning away rocks and debris and getting the site ready for further study.

And so we work, hauling rocks away in wheelbarrows and sifting sand through screens, making sure we don't miss anything.

On the evening of the first day, as the sun begins to cast a soft golden glow on the cliff face, we welcome an invited guest: The codiscoverer of the site, Calvin Sarver, now 60, has just arrived from town to tell us about that bizarre day 30 years ago when the cliff seemed to rain Clovis artifacts. He walks to the cliff and points at a spot on the wall six feet higher and 15 feet east of the place where both Taylor and Lahren had previously dug.

"It was right here," Sarver says. "Just about this high."

Lahren is stunned. "You're sure about that?" Sarver seems certain, although he grants that it's been 30 years.

Unlike Taylor, who died in 1991, Lahren now has a chance to set the record straight. "You know, I just assumed Taylor excavated the right place," he says. "I can't believe it. We just sifted through his leavings. Well, I guess we better re-do this grid."

The digging is ploddingly slow, the weather hot. It takes us two more days to clear the site and grid it, using Sarver's information. With our grid in place, we begin removing soil a section at a time, an inch at a time, and screen it through table-size sieves. We save bits of old bone—most likely bison and deer—in one paper bag, and place fragments of rock that look as though they may have been worked by humans into another. On the evening of the fifth day we break our encampment and agree to reconvene in a few weeks for a second round of digging.

Then it's late July, and after another week's work, we're done for this year. At last we have chipped and scrubbed our way down to the bedrock. The shaved and sculpted outcrop now looks the way our Clovis family saw it.