thing, that never shrunk, and shivered and shook, and groaned, and tilted up and down, then these layers of mud and sand would have remained flat on the floor of the ocean, and there would be no ledge for us to observe and discuss. But quite otherwise is the truth.
A very shaky affair is our old planet. It is cracked and mended in millions of places ; wherever a quartz vein exists there was once a rent. The rocky crests of the loftiest mountains are often gleaming with imbedded fossil shells, that were ocean-born. Deep down in the great mines one hears the groaning of the nighty strata of rocks. This is a cooling planet, and as it cools it shrinks, and the hard crust rises in great crumples of mountain ranges. On a small scale, a baked apple is wrinkled; the inside has become smaller, while the skin has not shrunken. During this shrinkage our infant ledge was, with all the adjoining rocks, pushed sidewise into waves or crumples, thus forcing what was once a flat surface of rock into various slants or angles, and at the same time pushing them out of water. Through many million years the agencies of air and atmosphere, and heat and cold, and ice, and mighty glaciers and running waters, have worn away the highest parts of the ridges, and left ..the hardest portions tipped on edge by the