Dazed and frightened, yet not without a certain thrill of the scientist’s or archaeologist’s delight, I examined my surroundings more closely. The moon, now near the zenith, shone weirdly and vividly above the towering steeps that hemmed in the chasm, and revealed the fact that a far-flung body of water flowed at the bottom, winding out of sight in both directions, and almost lapping my feet as I stood on the slope.