The various classes and groups of animals, both in the order of development from the simple to the complex and in the time of their arrival, are in the order named: first the small, one-celled animals (many species of which are found today) then more complex organisms of the invertebrate division, later the fishes, amphibians, reptiles, and mammals, including man. The story told by the geologist is in perfect agreement with those laws of development which we call evolution. The lowest, simplest forms of life are the oldest as is shown by their fossil remains (bones, shells, etc.) found in stratified or water-laid rock. These fossils were deposited in sediment as it formed in sea and lake thousands and millions of years ago. In the movements of the earth’s crust the sediment of ancient sea and lake bottoms was raised above the water and became land, the sediment hardening into rock. All sediment is formed on a level, but in its up-heaval--generally slow, sometimes violent--it is often tilted at various angles exposing its edges. It is from this out-cropping, stratified rock (the sum of which is often several miles in depth) that forms the outer part of the earth’s crust that the geologist reads the story of creation. The oldest or lowest water-laid rock is the archaean in which there are no fossils. Above this, in the stratum formed in a later period are found evidences of the beginnings of life. After millions of years of growth and development the shell fish, at the top of the invertebrate group, is produced. Then comes a period of uncounted millions of years in which the fishes, the lowest of the vertebrates, are being developed--millions of years to bridge the chasm between the two main divisions of the animal kingdom; millions of years to produce a backbone! Other long periods of time, filled with change and development, come and go--the age of the coal plant and of the frogs, succeeded by the age of reptiles, giant monsters, cold-blooded and of small brain, swarming sea and land. Long ages pass; the reptilian monsters have become extinct, leaving as their representatives only a few dwarfed species--the crocodile, the lizard, the snake, the turtle. Of mammals the lowest orders arrive first, followed by the more highly developed until finally man appears.