ELIZABETH CITY, N.C. The morning began with a brief but vigorous argument - call it a discussion - in the hotel lobby. The breakfast table was loaded with road maps, Google Earth printouts and colorful elevation images intended to help the three researchers locate a curious landscape feature. They were hunting for slight depressions in the earth, dimples almost invisible at ground level but so striking from the air that, for a number of years, they captivated the entire country. Scientists in the mid-1900s devoted careers to their study, debated furiously in print, were celebrated, vilified, laughed at and honored,...