From Science News On-Line
From Science News On-Line
Early New World Settlers Rise in East
Archaeologist Joseph McAvoy (right) and Lynn McAvoy work at Cactus Hill. (Kenneth Garrett/National Geographic Society)
Virginia, a state perhaps best known for its links to colonial America, contains some of the earliest known remains of prehistoric Americans, according to data presented in Philadelphia last week at the annual meeting of the Society for American Archaeology.
Analyses of soil, plant, and animal remains and stone artifacts that researchers found in layers of a sand dune known as Cactus Hill suggest that people lived there at least 15,000 years ago. That's well before the appearance of the Clovis culture, long regarded as the first in the New World.
Sites from Florida to Alaska have yielded distinctive Clovis stone points. Such finds date at earliest to 11,500 years ago.
"We think people went to Cactus Hill, on and off, beginning at least 15,000 years ago," says Joseph M. McAvoy of Nottoway River Survey-Archaeological Research in Sandstone, Va., who directs research at the site.
Clovis culture may have flourished first in the southeastern United States and then spread westward, McAvoy proposes. However, many archaeologists have assumed that Clovis people crossed into North America from Siberia about 12,000 years ago and then moved eastward.
Excavations at Cactus Hill, which lies along the Nottoway River 45 miles south of Richmond, began in 1993. Wind has carved out this dune and others in the area over the past 25,000 years, McAvoy says. The dune contains enough silt and clay to hold its deposits together.
McAvoy's team identified two sediment layers containing signs of human occupation. The upper level, radiocarbon dated to 10,920 years ago, contained Clovis-style spear points. The lower level, radiocarbon dated to 15,070 years ago, yielded stone points and other implements without Clovis features.
These stone points and blades exhibit microscopic wear marks typical of butchery and hide scraping, reports Larry R. Kimball of Appalachian State University in Boone, N.C. He calls the points "logical precursors" of Clovis points.
Charcoal from the dune's lowest level dates to as early as 19,700 years ago, says McAvoy. That material may have resulted from either human activity or forest fires.
Several lines of evidence lend credence to these dates, McAvoy says. Optically stimulated luminescence dating, a technique for estimating the last exposure of buried soil to sunlight, confirms the site's radiocarbon dates, holds James K. Feathers of the University of Washington in Seattle.
Soil samples from Cactus Hill indicate that no major geological disturbances affected the two archaeological deposits, according to analyses by James C. Baker of Virginia Polytechnic Institute and State University in Blacksburg.
Moreover, artifact-bearing soil at the site contains high concentrations of microscopic plant remains, another sign that the human-occupation levels have remained undisturbed, says Lucinda J. McWeeney of Yale University.
Microscopic studies of soil structure at Cactus Hill, however, suggest that geological forces may have affected the artifact layers, assert Carole A. Mandryk and J. Taylor Perron of Harvard University. "I don't think it's been proved that these artifacts come from undisturbed locations," Mandryk says.
Vance Haynes of the University of Arizona in Tucson also views Cactus Hill cautiously. He awaits further radiocarbon tests before accepting the site's age estimates. Haynes says that it's "most unusual" that only 6 inches of soil separate the two occupation levels and so must cover a span of about 5,000 years.
Still, "Cactus Hill is the best candidate for a pre-Clovis site in a long time," Haynes remarks.
Dennis Stanford of the Smithsonian Institution in Washington, D.C., argues that pre-Clovis artifacts at Cactus Hill resemble western European specimens from about the same time. He raises the controversial possibility that seagoing Europeans settled eastern North America and founded the pre-Clovis culture.
Whatever the case, the existence of pre-Clovis folk at Cactus Hill looks convincing, says Michael Johnson, an archaeologist at Fairfax County Park Authority in Falls Church, Va., who's conducting a separate excavation at Cactus Hill.