We cannot disprove the postulate that the universe was created one second ago, complete with all our apparent memories of our own earlier days, or that it was not created in 4004 B.C., with all the apparent record of earlier billions of years. But that would not make sense, and we must pretend, at least, that both we and the universe are sane. George Wald, Scientific American , vol. 191, Aug. 1954, p. 48.
Time is in fact the hero of the plot.
The time with which we have to deal is of the order of two billion years. What we regard as impossible on the basis of human experience is meaningless here. Inasmuch as life has evolved gradually, changing from age to age, the rocks of each geologic age bear distinctive types of fossils unlike those of any other age. Fossils thus make it possible to recognize rocks of the same age in different parts of the Earth and in this way to correlate events and work out the history of the Earth as a whole. The geologist utilizes knowledge of organic evolution as preserved in the fossil record, to identify and correlate the lithic records of ancient times.