Ancient ax helps date early Greeks.

In the sediment of an ancient lake bed, Boston University archaeologists have found a flint hand-ax that provides new clues to the prehistoric settling of Europe. The ax, assigned a preliminary age of between 200,000 and 400,000 years, confirms that early Stone Age human ancestors lived in Greece.

"This is the most significant discovery for the early prehistory of Greece in some 30 years," asserts James R. Wiseman, director of the expedition known as the Nikopolis Project. He and his colleagues announced the find last week at a press conference in Boston.

In May, the scientific team began fieldwork in the region of Nikopolis, a site on the western peninsula of Greece founded by the Roman emperor Augustus in commemoration of a 31 B.C. war victory. On June 3, expedition member Curtis Runnels noticed the ax sticking out of undisturbed sediment in an eroded gully running through the lake bed, about 120 miles north of Nikopolis.

The researchers say the 9-inch-long specimen is an Acheulean hand-ax, named for a French site where similar implements turned up in the early 1800s. In western Europe and Africa, archaeologists have found numerous Acheulean hand-axes at sites spanning the period from 1.6 million to 200,000 years ago. Scientists do not know exactly how human ancestors used these pieces of flaked stone, which feature two sharp edges converging to a point at one end. Studies suggest the hand-axes may have served as cutting tools for tasks such as butchering large animals and digging up tubers.

Investigators generally agree that direct ancestors of modern humans - principally Homo erectus, but also a more recent group known as archaic Homo sapiens - fashioned Acheulean artifacts. Runnels suspects that archaic H. sapiens produced the Greek hand-ax, since it dates to around the time when H. erectus disappears from the fossil record.

If additional Acheulean finds emerge during fieldwork at several nearby lake beds of a similar age, Runnels says, the archaeological evidence will support the theory that archaic H. sapiens - rather than H. erectus - first settled Europe.

Researchers have found several skulls of human ancestors at central European sites dating to about the time of the Greek hand-ax, but the classification of the fossils remains controversial, Runnels says. Moreover, the skulls came from sediment lacking any stone tools or other distinctive artifacts.

Although the new find helps to close a gaping hole in knowledge about human ancestors in central Europe during the early Stone Age, scientists cannot conclusively peg the flaked stone to either H. erectus or archaic. H. sapiens, contends archaeologist Ofer Bar-Yosef of Harvard University. "We need skeletal material from the Greek site to confirm who made the hand-ax," he argues.

Bar-Yosef supports a theory that several waves of H. erectus first entered Europe sometime between 1 million and 500,000 years ago, migrating from Africa through the Middle East and then westward along the Mediterranean coast.

Next year, the Boston team plans to excavate the Greek site more thoroughly. Runnels points out that the soil contains clay that hinders the preservation of fossilized bones. "But before this year," he adds, "I wouldn't have given myself much of a chance of finding an Acheulean hand-ax at the site either."