Guotong Ji

The Transition Period is the novel’s name for an ancient stage in the history of the Earth, encountered not as an abstract date but as a change in the rocks and fossil record beneath the surface. It gives the underground journey a scale beyond human history: strata become evidence of successive forms of life, and a geological classification becomes a landscape through which the explorers travel.

Geological Setting and Signs in the Rock

As the explorers pass from shining lava into living rock, the narrator identifies their surroundings as a state of transition, marked by Silurian stones. The classification is tied to rocks common in parts of England once inhabited by the Silures. The shift in the gallery’s walls gives the period a physical presence: the journey is no longer simply through a volcanic passage, but through formations that the narrator reads as evidence of Earth’s earlier history.

The narrator interprets the sedimentary schists and calcareous rocks as deposits formed when waters covered the Earth, and contrasts them with the granite they have left behind. Later, the rock walls display marble marked by the remains of primitive animals. Their changing fossil record makes the passage seem to disclose successive stages of creation rather than a uniform underground world.

Fossils and the Ascent of Life

Among the fossils, the narrator notices forms more developed than the trilobites seen earlier, including fish whose anatomy he understands as an early form of the reptile. He associates such animals with the Devonian seas, where, in his account, they were deposited in vast numbers in newly formed rock. The sequence encourages him to read the strata as an ascent in animal life, with humanity at its summit.

The geological evidence does not have the same force for every member of the expedition. The narrator treats the fossils as warnings about the direction and significance of their journey, but Professor Hardwigg presses on. The contrast makes the period both a scientific record and a test of interpretation: the rocks offer clues, yet those clues do not by themselves determine how the explorers will act.

An Ancient Flora Made Visible

At the subterranean shore, the Transition Period returns as a living-looking botanical world. Professor Hardwigg identifies the vegetation as the flora of this second, transitional age: plants that are humble in the modern world appear as enormous trees, including hundred-foot lycopods, pine-height flowering ferns, and gigantic grasses. His enthusiasm answers the narrator’s earlier reading of the fossil-bearing rocks with a spectacle of scale and growth.

The narrator regards the preserved plants as evidence that learned naturalists had reconstructed ancient forms with remarkable skill. The underground landscape thus joins direct observation to scientific inference: what had been pictured from geological evidence now stands before the explorers in magnified form. The period is not presented only as a vanished chapter; within the novel’s subterranean world, its vegetation seems to have survived as an overwhelming environment.

Deep Time and the Novel’s Geological Imagination

The narrator’s vision of the prehistoric world extends the sequence of life into an immense chronology. In his reverie, mammals disappear first, followed by great birds, reptiles, fish, crustaceans, mollusks, vertebrates, and finally the zoophytes associated with the Transition Period. The panorama makes human presence seem radically belated: the narrator imagines himself as the only human heart beating in an unpeopled world, amid exaggerated vegetation and a climate without seasons.

That imaginative sequence belongs to the novel’s nineteenth-century engagement with paleontology, not to a timeless scientific consensus. The narrative also describes the contemporary dispute over evidence for human antiquity: the Moulin-Quignon jawbone, found in 1863 fourteen feet underground with stone implements, was defended as evidence of Quaternary humanity, while Elie de Beaumont disputed the age of its stratum. Further discoveries and alleged traces of human handiwork were then used by some scholars to place humanity much earlier, even before the mastodon and in the Pliocene. Against that background, the Transition Period’s fossil and plant worlds turn disputed geological time into a dramatic sequence that the expedition can traverse and the narrator can imagine.