Science Marches On: A "volcanic upheaval" could not bring part of the ocean floor to the surface as is described here- this was written before the theories of continental drift and later plate tectonics were fully accepted by scientists. On the other hand, while we have yet to find anything quite like in the story, Lovecraft was correct in assuming that the ocean would be a real-life Eldritch Location full of bizarre creatures. Of course, the narrator himself is not quite sure it happened, and no one can find any signs of the island. It is vaguely suggested that, as Lovecraft was wont, it is a mixture of dream and reality. "Volcanic upheaval" is, perhaps not unreasonable for the time, just the only explanation that the narrator can come up with.
Film:
Development Gag: The Cambarro family (Marsh in the original novel) is named after Combarro, the town where the film was shot in.
