Mt Alvernia. Late one afternoon, as the sun slanted into Exuma Sound, I threw a mask and fins into a kayak and headed up Fernandez Bay's Bonefish Creek toward the Boiling Hole, a bluewater cavern that, through some alchemy of ocean, current, and creek, churns like a pot at high tide. I paddled for an hour, keeping the markers, tied to the mangrove branches, on my left. I passed the last one; no hole. I kept going. I got a feeling in my stomach that the water was sliding downhill, that I was being sucked into a drain. Spooked, I started to follow my wake back out, but the water had begun to percolate. Beneath the kayak the silt bottom opened into a limestone cavern, its recesses reaching farther than I could see. The idea had been to hop out and go snorkeling. You'd see great fish down there—snapper, grouper, barracuda.