Divers hunt prehistoric man in Florida river
By Diane Hirth - Tallahassee Bureau, Ft. Lauderdale Sun-Sentinel
AUCILLA RIVER -- In a place so steamy that shoe leather gets moldy almost overnight, an ancient river of tea-black water laps over perfectly preserved bones more than 12,000 years old.
The Aucilla River follows a quixotic path in north Florida, plunging underground several times before flowing into the Gulf of Mexico.
For geologist and zoologist David Webb, it has become a river of prehistoric dreams, revealing clues to when and how man and mastodon met 500 to 600 human generations ago.
Snaking along the mostly wild edges of Jefferson, Madison and Taylor counties, the Aucilla has produced what may be the oldest evidence of human culture in North America: a 12,200-year-old, seven-foot mastodon tusk butchered with deep cuts that pushes back previous estimates of the advance of Paleoindians into the New World; an incised and beveled spear-shaped piece of ivory; a fish hook made from a large animal bone.
"We're starting to span the interval when the big extinctions occurred. Maybe we'll tease out the answer of whether man was causing these extinctions," says Webb, a University of Florida professor and curator of fossil vertebrates at the Florida Museum of Natural History.
"Did they hunt to death the big animals in a few centuries? I think that's the big question laid at our feet.
"This is a quiet, wet place that preserves a lot of stuff."
The mystery that might be unmasked by fragments found in the Aucilla mud is what occurred between 10,000 and 12,000 years ago. In the middle of that time, mastodons, mammoths, giant Sloths, horses and camels disappeared from this hemisphere after grazing here for millions of years.
Until Webb's research, the generally acknowledged oldest artifacts confirming man's presence and his hunting of large game were 11,200 to 11,500 years old, from the Clovis site in New Mexico.
But this chapter of prehistory remains faint. Elsewhere in the eastern United States, for instance, the artifacts of long ago generally have been plowed over or eroded away.
"I go about it as a geologic prospector would," Webb says of his attempt to dissect a distant time. "It's just like a good murder mystery"
Other scientists have dismissed Webb's style of river archeology, unable to see beyond the swamprot setting and the jumbled juxtaposition of beer can and mastodon bone at the river's bottom.
Sure, one might find a handsome spear point or the remains of an extinct beast, but hasn't the river churned everything together into an indecipherable thousands-of-years-old stew?
"The old bugaboo that professors started was 'There is no good science in the bottom of a river.' Pottery and beer cans. and ivory together are a meaningless jumble to an archaeologist," Webb says.
"So the professors basically walked away from it because they said it was not impeccable, not dateable."
It took time for Webb to become a believer in the scientific worth of this river's relics. But he was fascinated by the amateur divers and collectors and their amazing finds: "They had guts. They were like old pioneers. They'd go down in the darkest waters where you couldn't see anything. They led us to the right places.
"It was like coming awake slowly," he says. Finally, Webb flashed on the notion that careful dissection of Aucilla riverbed could work. That's because he remembered collecting skeletons of mastodon and mammoth from river as far back as 1970, "our mammals were in place, in sediment. They hadn't moved for 12,000 years."
Webb is careful to employ much of the same plodding techniques used at archaeological sites on land.
Ten years ago, he and an ever changing band of volunteers and students began carefully digging, trowel by trowel, into meticulously laid-out grids on the river bottom.
Each spring and fall, they come for about a month -- swatting at biting deer flies and scratching rashes left by lush poison ivy that crowds the riverbanks.
To pierce the black shroud of water, the divers use 1,000-watt lights.
And much of their gear is improvised to fit the watery conditions. The dredge sucking up river silt is modified gold-mining equipment.
"Everyone thinks about the romance and adventure of Indiana Jones," says Webb, a lean and tan 59-year-old. "But all of this is work, incredibly tedious work, to make it stick. It's like a lawyer preparing a case. If anything, we've been too slow and cautious.
"And for every 10 hours spent on the river doing excavations, there are 90 hours spent back in the museum cataloging the specimens and preserving them so they don't crack or break."
At the river site, sediment layers and their contents are meticulously documented. A grape seed, a gourd seed, a nut, chunks of wood -- all have been found preserved in the layers and all are useful for accurate carbon dating.
Working in up to 40 feet of water, Webb and the other divers dig as deep as 15 feet into the river bottom.
At one key site, each millimeter of sediment below the water equals about a year. One meter? One millennium. And so on. Five is about 5,000 years. One area of the river that's mapped is 37,000 years old at its base.
For a visitor, there's little to see besides bubbles on dark water, marking where the divers are. A volunteer is out on the "screendeck," a floating barge where the silt is sifted and doublechecked for anything missed down below.
Occasionally, though, Webb's crew rigs up an underwater TV camera, and one can see a murky picture of excavations as they occur.
Webb's obsession has a name, the Aucilla River Prehistory Project, and a newsletter. It receives money from both National Geographic Society and the Florida Secretary of State's division of historical resources.
But aside from the formality of the scientific quest, there is a cockeyed enthusiasm here that reminds one of a little boy digging rocks out of the mud.
It is what lures the volunteers who have kept this operation alive.
"Yes, there is a good science going on", says Joe Latvis, who was a volunteer diver for years before becoming project operations manager.
"But there's some kind of magical spark, too. Just to know these were deposited in a world much different than today is a transcendental experience. I don't mean to be too nutty about it, but you realize you are the first person to look at something that may have been from just after the Ice Age peaked ... That's the fire that burns in the belly of folks like myself."
What today is a flowing river was once a series of isolated sinkholes lined with rocks, peat and mud. That's a key reason why much of the critical evidence here wasn't washed away.
Webb scribbles on a yellow pad with professorial enthusiasm and gestures excitedly with his hands as he goes through some questions that the Aucilla may answer about the hunters who wandered across the Bering Strait and down a narrow ice-free corridor about 15,000 years ago.
Were human migrations first to the east or west? How early were men, women and children definitely in what is now known as Florida? How sophisticated were their weapons? Did they use spear throwers? Was there a human caused "prehistoric blitzkrieg" that caused the big mammal extinctions?
"We used to think the earliest people were much more tied into nature and less technically sophisticated. But things were going along quietly without much change, and suddenly, boom!
"If humans show up and 200 years later everything is wiped out, it shows you a ferocious people. There are theories that human overkill wiped out the mastodons. We think we've got evidence in this river that will help sort this out."