NARRAGANSETT, R.I. - In 1994, archaeologist Fredrik Hiebert rode around northern Turkey in a dirty white Toyota van looking for evidence of ancient civilizations around the Black Sea. Every time he and his team would ask locals for the whereabouts of centuries-old ruins, they'd get the same response. "Everyone kept pointing us to the sea," Hiebert recalled. Hiebert knows now why they did. After some preliminary trips, the University of Pennsylvania professor and other scientists will go on a first-ever effort to excavate ancient ships and a possible human settlement left mummified in the Black Sea's oxygen-free waters. Scientists hope...