chunk: The main story of the novel is the narrative of the adventures of Adam More, a British sailor shipwrecked on a homeward voyage from Tasmania. After passing through a subterranean tunnel of volcanic origin, he finds himself in a "lost world" of prehistoric animals, plants and people sustained by volcanic heat despite the long Antarctic night.
  A secondary plot of four yachtsmen who find the manuscript written by Adam More and sealed in a copper cylinder forms a frame for the central narrative. They comment on More's report, and one identifies the Kosekin language as a Semitic language, possibly derived from Hebrew.