Scientists say they've determined the age of Neanderthal remains found in a Spanish cave, an important clue in the transition from Neanderthal to Homo sapiens. Previous estimates putting the age of the remains in the El Sidron cave, one of the westernmost Neanderthal sites on the Iberian Peninsula, at only 10,000 years was the result of inexact measurements, researchers at the University of Oviedo in Spain reported Tuesday. "Some previous datings that stated the remains were only 10,000 years old are inconsistent and cannot be considered credible," researcher Marco de la Rasilla said. "They would be highly disputed in the discussion about when Homo neanderthalensis became extinct." In order to adjust the age of these Neanderthals, De La Rasilla and his team analyzed new results from laboratories in France and Britain, confirming that the Neanderthals from the El Sidron cave lived some 49,000 years ago. "The previous measurement of 10,000 years for this episode was due to a contamination issue," De La Rasilla said, noting the Carbon-14 dating of samples had become contaminated with modern carbon, making them appear younger than they actually were.