sentences:  It is perhaps the earliest novel dealing with the afterwards popular theme of humanity being replaced by intelligent apes in the future, later epitomized by Pierre Boulle's "Planet of the Apes".A bus is trapped in the cave-in of a tunnel, and its passengers are preserved for millennia in a state of suspended animation.When their vehicle is ultimately uncovered they awaken to a future in which humankind has vanished from the face of the earth, and gorillas have evolved to intelligence and become the dominant species.