THE TIME SCALE AND SOME EVOLUTIONARY PRINCIPLES
To most of us, paleontology is the name of a sort of genteel outdoor science concerned with the collection and gross description of old bones and hardened mud blocks containing preserved animal tracks. To the paleontologist and, for that matter, to any novice who has had the good fortune to pass through what might be called the "Darwin-to-Simpson reading stage," no definition could be further from the truth. Just as history, to the historian, is alive and a part of the continuing pageant of human experience, so is the study of the life of the past a living science to its devotees.
The study of fossils cannot tell us a great deal about the natural forces that shape the evolutionary process, but it does furnish us with guidelines for the consideration of information derived from other sciences. As G. S. Carter1 has put it, "The part of paleontology in the study of evolutionary theory resembles that of natural selection in the process of evolution; it serves to remove the inefficient but cannot itself initiate." It is clear that we can, and should, present only the most superficial survey of the fossil record and its interpre-