CREATION BY EVOLUTION
ing up of the continental blocks and a sinking of the sea-levels, and a new pulse beat of the earth takes place.
When the continents are extensive and high the climates are zonal—that is, there are zones of different climates in different regions. The climate is cold at the poles, warm at the equator, arid in central regions, and moist along coasts. When the continents are contracted and worn down low the climate is non-zonal and equable, the conditions of life are easy, and evolution is relatively slow. The rocky strata of earth’s crust show clearly that there have been several great continental pulse beats. A section of the walls of the Grand Canyon, for example, affords an opportunity to read the book of geology at a place where the earth has herself turned back the pages. To one who has learned to read the language in which it is written, nothing could be more certain than the story thus revealed. It is a true story, unspoiled and unedited by the hand of man. Those who have become experts in reading the record of the rocks agree in the interpretation of its pages, at least as to its main plot. About some minor details different versions are offered. It is clear, however, that since the earth reached its present diameter, at least a billion years ago, there have been no less than half a dozen major pulse beats of the earth; and numerous minor rhythmic changes have been superimposed upon the major rhythm. It is also certain, as shown by fossils, that the earth has been the abode of life during numerous physical and climatic changes of far-reaching extent and of great severity.
Leaving now the exceedingly large units of the universe, let us put on our shrinking caps and magically pass to the exceedingly small world of the atom. Modern physicists have revealed to us that the atom, once thought to be the smallest thing in existence, is really much like a miniature
[ 358 ]
