The film JURASSIC PARK may have brought dinosaurs back to life, but scientists are still not sure what caused their extinction 65 million years ago at the end of the Cretaceous geological period. Was it a series of massive volcanic eruptions? Or was it the result of a giant meteor striking the Earth? Now a group of French scientists may finally have solved the riddle. They have studied the thin layer of rock that forms the boundary between the Cretaceous and Tertiary periods - the "KT boundary layer" - and have found fragments of magnetite, a magnetic rock. Their findings are powerful and perhaps conclusive evidence that the dinosaurs were killed off by not just one meteor impact, but quite possibly by at least two and maybe more meteors striking different parts of the Earth at about the same time.