Page:The Music of the Spheres.djvu/306

 Red clay is composed of iron and silica and represents all that is left of the minute shells which cover the tiny sea-animals which flourish in such countless multitudes throughout the ocean. These shells, after the animal dies, drift downward in ceaseless showers and the lime, of which they are largely composed, is dissolved during the long journey to the bottom. "Ooze" is found in water less deep and is formed by the accumulation of minute shells of different species. Minute shells of the same species have formed great thicknesses of limestone or of chalk even as grains of sand build in time their banks of sandstone. Such information as this is, of course, disclosed by the penetrating eye of the microscope. Chalk cliffs, now dry land, form thousands of miles of habitable land in Europe, while coral sand pressed into rock forms the unique foundation of the Bahama Islands, the Bermudas, many islands of the Pacific, and the Great Barrier Reef extending for a thousand miles along the shores of northern Australia!

Looking again about our own country on the land that lies cradled between the eastern and the western mountains of the United States, one cannot help but regard with awe the magnificent stretches of time it must have taken for this great area to have been formed beneath the sea. This alone proves the great age of the earth. Because it was raised slowly, the strata lie there little disturbed, one over the other, "like the leaves of a great stone book," containing the history of the earth. A good view of the river strata may be obtained in the canyon of the Colorado river, for this mighty river has carved a bed through the stratified deposits to a depth of from 3000 to 6000 feet.