TMQ is informative!

A Few Cosmic Thoughts: Complex animals, including the first vertebrates, seem to have appeared on Earth around 540 million years ago. This period is known to that paleontologists as the Cambrian Explosion, because animals went from unknown to common in a short time by geological standards. At least that's how it seemed, since no fossils of complex animals older than about 540 million years had been found. Was this because there were no older complex animals, or because they lacked the kind of hard bone structures that leave fossils? Recently a team of researchers at Nanjing University in China found in Precambrian rocks evidence of animals similar to mollusks that lived 600 million years ago. Animals have roamed our world for 600 million years. Every time the tools of astronomy improve, the universe is shown to be larger -- and every time the tools of paleontology improve, life is shown to be older. Meanwhile in Dong Xa in Vietnam, Peter Bellwood and Judith Cameron of Australia National University recently found the ruins of a log boat identical to a distinctive design that dates to Rome during the reign of Caligula. Coins and other artifacts found with the boat date to the same period. Could the Romans have gotten as far as Vietnam? Every time the tools of archeology improve, the human past becomes more tantalizing.