PALEONTOLOGY:
Earliest Signs of Life Just Oddly Shaped Crud?
Richard A. Kerr
A claim for the oldest known fossils-fossils that have entered textbooks as the oldest ever found-is under attack as a misinterpretation of intriguingly shaped but purely lifeless minerals. A paper in this week's issue of Nature argues that the microscopic squiggles in a 3.5-billion-year-old Australian chert are not fossilized bacteria, as was claimed in a 1993 Science paper, but the curiously formed dregs of ancient hot-spring chemistry.