Australia's new ocean-going research vessel Investigator has discovered extinct volcanoes likely to be 50 million years old about 250 kilometers off the coast of Sydney. They were discovered in 4,900 meters of water during an expedition searching for nursery grounds of larval lobsters. At the same time the ship was also routinely mapping the seafloor. The largest of the four volcanoes is 1.5 kilometers across the rim and rises 700 meters from the sea floor....