Digging up debate in a French cave.

More than 50 years ago, Henri Delporte excavated a French cave known as Grotte des Fees at Chatelperron. He unearthed many large stone tools characteristic of Neandertals as well as a surprise: small, sharpened points seemingly made by the species toward the end of its evolutionary run. Archaeologists have attributed the finds, now known from several western European sites, to a final phase of Neandertal culture called the Chatelperronian.

Delporte's work has now sparked a heated row over interactions between Neandertals and modern humans. Paul Mellars of Cambridge (England) University says that other tools in the cave indicate that modern humans with a distinctive toolmaking style known as Aurignacian inhabited Grotte des Fees between occupations by Neandertals bearing Chatelperronian tools. In Mellars' view, modern humans spread into western Europe around 40,000 years ago and coexisted with Neandertals for 10,000 years, until the latter species died out.

Mellars and his coworkers identified artifact-containing soil layers at Grotte des Fees using Delporte's published reports and unpublished excavation records held in a French museum. Radiocarbon measurements of animal bones from each layer indicated that an initial Chatelperronian occupation was from 40,000 to 39,000 years ago. Between roughly 39,000 and 36,000 years ago, Aurignacian material predominates, followed by a Chatelperronian return from about 36,000 to 34,500 years ago, Mellars holds.

Critics of Mellars' research, which was published in the Nov. 3, 2005 Nature, assert that Chatelperronian culture preceded Aurignacian culture by a few thousand years or more at Grotte des Fees and other sites, and that the two populations eventually met. Delporte, an inexperienced archaeologist at the time of his discoveries, inadvertently disturbed the positions of the few Aurignacian artifacts in the cave and left them scattered in deeper, older soil layers, contends Francesco d'Errico of the National Center for Scientific Research in Talence, France.

Delporte's accounts reveal that the original locations of artifacts and animal bones at the site weren't recorded. Also, because workers dug up mounds of soil and then dumped them back, sediment and artifacts from different layers are now mixed together. On closer inspection, even sediment identified as Aurignacian by Mellars' team contains mostly Chatelperronian tools, d'Errico says.