[The H.P. Lovecraft Omnibus 02] • The Complete Fiction of H. P. Lovecraft · at the Mountains of Madness, the Call of Cthulhu, the Case of Charles Dexter Ward, the Shadow Over Innsmouth, ... Witch House, the Silver Key, the Temple…

Wiki: The story is the testament of a tortured, morphine-addicted man who plans to commit suicide over an incident that occurred early on in World War I when he was a merchant marine officer.

In the unnamed narrator's account, his cargo ship is captured by a German sea-raider in "one of the most open and least frequented parts of the broad Pacific". He escapes on a lifeboat and drifts aimlessly across the sea "somewhat south of the equator" until he eventually finds himself inexplicably stranded on "a slimy expanse of hellish black mire which extended about me in monotonous undulations as far as I could see.... The region was putrid with the carcasses of decaying fish, and of other less describable things which I saw protruding from the nasty mud of the unending plain." He theorizes that this area was formerly "a portion of the ocean floor... thrown to the surface" by a volcanic upheaval, "exposing regions which for innumerable millions of years had lain hidden under unfathomable watery depths."

This is the 4th story featured in "The Complete Fiction of H.P. Lovecraft" published by Race Point Publishing.