"Hutton published a landmark treatise, Theory of the Earth, in which he set forth the principle of uniformitarianism: the present is the key to the past. He proposed the same processes of erosion, weathering, uplift and sedimentation that are sculpting the land today have been at work throughout the eons. ...In Hutton's day, uniformitarianism was a refutation of theories that called upon catastrophic events like the biblical flood to explain the way the world looked. But even as these deux ex machina theories fell to the wayside, Hutton's ideas continued to hold sway..."