Everything was white, from the top of Mount Franklin to the coast—forests, prairie, lake, river, beach. The waters of the Mercy ran under a vault of ice, which cracked and broke with a loud noise at every change of tide. Thousands of birds—ducks and wood-peckers—flew over the surface of the lake. The rocks between which the cascade plunged to the borders of the Plateau were blocked up with ice. One would have said that the water leaped out of a huge gargoyle, cut by some fantastic artist of the Renaissance. To calculate the damage done to the forest by this hurricane would be impossible until the snow had entirely disappeared. Spilett, Pencroff, and Herbert took this opportunity to look after their traps and had hard work finding them under their bed of snow. There was danger of their falling in themselves; a humiliating thing to be caught in one’s own trap! They were spared this annoyance, however, and found the traps had been untouched; not an animal had been caught, although there were a great many footprints in the neighborhood, among others, very clearly impressed marks of claws.

Herbert at once classified these carnivora among the cat tribe, a circumstance which justified the engineer’s belief in the existence of dangerous beasts on Lincoln Island. Doubtless these beasts dwelt in the dense forests of the Far West; but driven by hunger, they had ventured as far as Prospect Plateau. Perhaps they scented the inhabitants of Granite House.

In a complete, well-reasoned essay, identify the theme of the excerpt and explain how you determined that theme.