[3] He escapes on a lifeboat and drifts aimlessly, south of the equator, until he eventually finds himself stranded on "a slimy expanse of hellish black mire which extended about [him] in monotonous undulations as far as [he] could see....

He theorizes that this area was formerly a portion of the ocean floor thrown to the surface by volcanic activity, "exposing regions which for innumerable millions of years had lain hidden under unfathomable watery depths.

[5] Descending the slope, he sees a gigantic white stone object that he soon perceives to be a "well-shaped monolith whose massive bulk had known the workmanship and perhaps the worship of living and thinking creatures.

"[6] The monolith, situated next to a channel of water in the bottom of the chasm, is covered in unfamiliar hieroglyphs "consisting for the most part of conventionalized aquatic symbols such as fishes, eels, octopuses, crustaceans, mollusks, whales, and the like.

"[6] There are also "crude sculptures" depicting: men—at least, a certain sort of men; though the creatures were shewn disporting like fishes in the waters of some marine grotto, or paying homage at some monolithic shrine which appeared to be under the waves as well... [T]hey were damnably human in general outline despite webbed hands and feet, shockingly wide and flabby lips, glassy, bulging eyes, and other features less pleasant to recall.

Vast, Polyphemus-like, and loathsome, it darted like a stupendous monster of nightmares to the monolith, about which it flung its gigantic scaly arms, the while it bowed its hideous head and gave vent to certain measured sounds.

He mentions one abortive attempt to gain understanding of his experience: Once I sought out a celebrated ethnologist, and amused him with peculiar questions regarding the ancient Philistine legend of Dagon, the Fish-God; but soon perceiving that he was hopelessly conventional, I did not press my inquiries.

[8]Haunted by visions of the creature, "especially when the moon is gibbous and waning", he describes his fears for the future of humanity: I cannot think of the deep sea without shuddering at the nameless things that may at this very moment be crawling and floundering on its slimy bed, worshipping their ancient stone idols and carving their own detestable likenesses on submarine obelisks of water-soaked granite.

[17] In "The Call of Cthulhu", one of the newspaper clippings collected by the late Professor Angell mentions a suicide from a window that may correspond to the death of the narrator of "Dagon".