But neither ship nor land appeared, and I began to despair in my solitude upon the heaving vastness of unbroken blue. The change happened while I slept. Its details I shall never know; for my slumber, though troubled and dream-infested, was continuous. When at last I awakened, it was to discover myself half sucked into a slimy expanse of hellish black mire which extended about me in monotonous undulations as far as I could see, and in which my boat lay grounded some distance away.