School of Rock

'A really beautiful point [triangular stone] made out of chert was found in Mission Gorge," says Cindy Stankowski, director for the San Diego Archaeological Center. "There isn't any of this kind of chert [hard sedimentary rock] here. The archaeologists think it came all the way from Palos Verdes. If a stone was of really great quality and people liked to work with it, it could be traded up to 500 miles." Like most artifacts found in Mission Gorge, this three-inch-long point uncovered in 2003 is estimated to be from the late Holocene era, or within the past 1000 years. "It's hard to tell the exact age in San Diego sometimes because the strata is quite jumbled," says Stankowski. This is the result of farming, construction, or, most commonly, gophers and squirrels churning up the thin top layers.

As a result of a steady increase in real estate development, artifacts have been discovered with increasing frequency. There are currently more than 20,000 recorded archaeological sites in the county. One of the oldest is the C.W. Harris site near Rancho Santa Fe. "There's a distinct occupation there that's nine or ten thousand years old," says Timothy Gross, principal archaeologist for the cultural resource management firm Affinis. "It also winds up being one of the earliest excavated sites; the first one was conducted there in 1938."

On Saturday, April 14, Gross will lead a flintknapping workshop at the center. "Knapping is the process of banging two rocks together," says Stankowski. "The term comes from England; there's no flint here in San Diego. Felsite is the common stone [here], also quartz." Arrow points have been found as small as three quarters of an inch. According to Stankowski, making such a fine point is not easy. "Most people, if they lived back then, would have been starving."

The process of learning about a culture through the construction and use of replicated artifacts is known as experimental archaeology. "One of the coolest human inventions is when, two and a half million years ago, our ancestors figured out that inside a round rock, you could find a sharp edge by hitting it with another rock in such a way that it breaks and use the broken edge as a platform to break off another flake," says Gross. Stankowski cites a case in Africa in which archaeologists used reproduction stone tools to dismember an elephant to discover whether "early man" could have done the same. "It turns out they can," she says.

"By making stone tools and looking at debris, we learn what the debris means," says Gross. "Some kinds of flakes often thought of as waste are related to one technology, making arrowheads or knives, and others are related to making steep-edged scraping tools." Gross explains that quartz, a crystalline material, is difficult to work with. "It has internal crystal planes and fissures, and it was not until the past thousand years or so that people actually used it in any great quantity."

The oldest points that have been recovered were created by hammer percussion using hard rocks or softer, less-dense material like an antler or sandstone. The progression from hard hammers to soft was a major advance in technology, as a soft hammer will diffuse the force of the impact, giving one better control for breaking off flakes. Within the past thousand years, pressure flaking replaced soft-hammer percussion as the predominant technology used for knapping. "Instead of bashing a rock, you're using a piece of antler or bone and actually putting it on the edge that you want to flake and applying pressure to the edge as opposed to beating the edge. You're flaking it lightly to get the right angle set up -- flintknapping is all about how force is applied and at what angle," Gross says.

It takes Gross around 20 minutes to knap an arrowhead, 40 minutes to an hour if he adds a serrated edge. "Most people who [flintknap] today are either into it because they're really interested in the technology or they're into it for the art," he says. "I was in New Orleans a decade ago, at a shop in the French Quarter that sold Indian arts, like modern pottery and basketry. Up on the wall was a spear with a beautiful obsidian point. The flaking was exquisite; I knew it was done by hand." -- Barbarella

Flintknapping Workshop Saturday, April 14 10 a.m. to 2 p.m. San Diego Archaeological Center 16666 San Pasqual Valley Road Escondido Event is sold out Info: 760-291-0370 or www.sandiegoarchaeology.org